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KembaraXtra-Medicine- Angina Pectoris
Basic Information
Angina pectoris is a clinical syndrome of discomfort in the chest, jaw, shoulder, back, or arm caused by myocardial ischemia. Most commonly it is related to atherosclerotic (atheromatous) plaque in one or more large epicardial coronary arteries, but ischemia can also occur without obstructive coronary artery disease. Nonobstructive causes include uncontrolled hypertension, microvascular disease, valvular heart disease, hypertrophic cardiomyopathy, coronary spasm, and endothelial dysfunction. In general, any condition that creates an imbalance between myocardial oxygen supply and demand can produce an angina syndrome.
Classification of Angina
Chronic stable angina (also termed stable ischemic heart disease or chronic coronary artery disease) is typically predictable and follows a precipitating event such as climbing stairs, sexual intercourse, a heavy meal, emotional stress, or cold weather. Episodes usually resemble prior attacks in severity and are relieved by rest or the patient’s customary dose of sublingual nitroglycerin. It is usually caused by fixed coronary obstruction from atherosclerosis, commonly with one or more major coronary stenoses, often >70%. Unstable angina includes rest angina, recent-onset angina, and crescendo angina and is addressed under acute coronary syndrome. Rest angina occurs at rest, is usually prolonged (>20 minutes), and occurs within 1 week of presentation. Recent-onset angina is angina of at least Canadian Cardiovascular Society (CCS) Class III severity beginning within the past 2 months. Crescendo angina is previously diagnosed angina that becomes more frequent, lasts longer, or occurs at a lower threshold, defined as worsening by more than one CCS class within 2 months to at least CCS Class III severity.
Prinzmetal (variant) angina occurs at rest, is commonly triggered after cold exposure, and tends to be cyclical. It is associated with episodic ST-segment elevations on ECG and is due to coronary artery spasm with or without superimposed coronary artery disease; these patients are more prone to ventricular arrhythmias. Microvascular angina (syndrome X) refers to patients with angina symptoms, a positive exercise test, normal coronary angiograms, and no coronary spasm. In this condition, defective endothelium-dependent dilation in the coronary microcirculation contributes to abnormal regulation of myocardial perfusion and ischemic symptoms. Patients with chest pain and normal or nonobstructive coronary angiograms are predominantly women, and prognosis may be less benign than often assumed, with about a 2% risk of death or myocardial infarction at 30 days.
Refractory angina describes patients who, despite optimal medical therapy using at least maximal tolerated doses of two antianginal medications (plus aspirin and intensive risk-factor modification such as smoking cessation and tight control of hypertension, diabetes, and hyperlipidemia), continue to have angina along with objective evidence of ischemia. Other causes of angina syndromes include angina due to aortic stenosis, idiopathic hypertrophic subaortic stenosis, and cocaine-induced coronary vasoconstriction.
Functional Classification (Canadian Cardiovascular Society, CCS)
Class I: ordinary physical activity (walking, climbing stairs) does not cause angina; symptoms occur only with strenuous, rapid, or prolonged exertion at work or recreation. Class II: slight limitation of ordinary activity; angina occurs with walking or climbing stairs rapidly, walking uphill, activity after meals, exposure to cold or wind, emotional stress, or during the first few hours after awakening; angina occurs when walking more than two level blocks or climbing more than one flight of ordinary stairs at a normal pace in normal conditions. Class III: marked limitation of ordinary physical activity; angina occurs with walking one to two level blocks or climbing one flight of stairs in normal conditions at a normal pace. Class IV: inability to carry on any physical activity without discomfort; anginal symptoms may be present at rest.
ICD-10-CM Codes
I20.1 Angina pectoris with documented spasm; I20.8 Other forms of angina pectoris; I20.9 Angina pectoris, unspecified. I25.110 Atherosclerotic heart disease of native coronary artery with unstable angina pectoris; I25.111 Atherosclerotic heart disease of native coronary artery with angina pectoris with documented spasm; I25.118 Atherosclerotic heart disease of native coronary artery with other forms of angina pectoris; I25.119 Atherosclerotic heart disease of native coronary artery with unspecified angina pectoris. I25.700 Atherosclerosis of coronary artery bypass graft(s), unspecified, with unstable angina pectoris; I25.790 Atherosclerosis of other coronary artery bypass graft(s) with unstable angina pectoris; I25.791 Atherosclerosis of other coronary artery bypass graft(s) with angina pectoris with documented spasm; I25.798 Atherosclerosis of other coronary artery bypass graft(s) with other forms of angina pectoris; I25.799 Atherosclerosis of other coronary artery bypass graft(s) with unspecified angina pectoris.
Epidemiology and Demographics
Approximately one in three adults in the United States (about 81 million) has some form of cardiovascular disease. Based on NHANES 2007–2010, an estimated 15.4 million people have coronary heart disease, and about 7.8 million have angina. Angina is most common in middle-aged and elderly men. Among persons aged 60–79 years, roughly 25% of men and 16% of women have coronary heart disease; among those older than 80 years, the figures rise to about 37% for men and 23% for women. After menopause, the incidence of coronary heart disease and angina in women becomes similar to that in men. Even with improving survival over time, stable ischemic heart disease remains the leading cause of death in men and women (about 27% of deaths). Angina is the initial manifestation of ischemic heart disease in about 50% of cases, and about half of patients who present with acute coronary syndrome report preceding angina. Older population-based studies (Olmstead County, MN and Framingham, MA) reported an annual myocardial infarction rate of about 3%–3.5% per year among patients with symptomatic angina. Within 12 months of stable angina diagnosis, about 10%–20% progress to myocardial infarction or unstable angina.
Physical Findings and Clinical Presentation
Evaluating chest pain requires attention to quality, location, severity, duration, radiation, associated symptoms, provoking factors, and relieving factors. Anginal pain is often described as squeezing, griplike, suffocating, or heavy; it is rarely sharp or stabbing and typically does not change with position or respiration. The classic Levine sign is a clenched fist placed over the precordium. Many patients describe angina not as “pain” but as tightness, pressure, or discomfort. Atypical presentations are more common in women and older adults and may include nausea, vomiting, midepigastric discomfort, sharp (atypical) chest pain, dizziness, or syncope. Ischemic discomfort lasting longer than 20 minutes should raise concern for acute coronary syndrome. Women are more likely than men to report atypical chest pain or discomfort (reported by 65% in the WISE study). Elderly patients and those with diabetes may present with non–chest pain symptoms such as dyspnea, fatigue, or diaphoresis.
Etiology and Risk Factors
Key risk factors include advanced age, male sex, and genetic predisposition such as a family history of premature coronary artery disease in first-degree relatives (men <55 years, women <65 years). smoking increases the risk of first myocardial infarction nearly threefold. other major risks include hypertension, hyperlipidemia, impaired glucose tolerance or diabetes mellitus, prior stroke peripheral arterial disease, chronic kidney metabolic syndrome, physical inactivity, and obesity (bmi>30% over ideal). Higher childhood BMI is also associated with increased adult coronary heart disease risk.
Several conditions increase myocardial oxygen demand, including hyperthermia (especially with volume contraction), hyperthyroidism, and cocaine or methamphetamine use. Cocaine is used regularly by more than 5 million Americans and leads to over 64,000 emergency department evaluations yearly to rule out myocardial ischemia; it causes sympathomimetic toxicity, increases oxygen demand, induces coronary vasospasm, and can cause infarction in young patients, while long-term use accelerates stable ischemic heart disease. Severe uncontrolled hypertension increases myocardial oxygen demand and reduces subendocardial perfusion by increasing left ventricular wall tension; hypertrophic cardiomyopathy and aortic stenosis can produce even more severe hypertrophy and wall tension. Ventricular or supraventricular tachycardias can also raise oxygen demand and may require ambulatory monitoring for diagnosis.
Reduced oxygen supply can trigger angina as well. Anemia may cause angina when hemoglobin falls below about 9 g/dL, and ST–T changes (depression or inversion) can occur at hemoglobin levels below about 7 g/dL. Hypoxemia from pulmonary disease such as pneumonia, asthma, COPD, pulmonary hypertension, interstitial fibrosis, or obstructive sleep apnea can precipitate angina. Additional associated conditions and exposures include polycythemia, leukemia, thrombocytosis, hypergammaglobulinemia, oral contraceptive or hormone replacement therapy use, coronary artery calcium (linked to higher MI risk), long-term NSAID use, and traffic-related air pollution (dilute diesel exhaust), which promotes ischemia and adverse cardiovascular events. Low serum folate (needed to convert homocysteine to methionine) is associated with increased fatal coronary heart disease risk; hyperhomocysteinemia damages endothelium and promotes arterial smooth muscle proliferation and is an independent risk factor for coronary events, particularly in type 2 diabetes. Elevated high-sensitivity C-reactive protein (cardio-CRP) reflects systemic inflammation and is linked to accelerated atherosclerosis. Other noted associations include depression, vasculitis, elevated lipoprotein-associated phospholipase A2, elevated fibrinogen, low red blood cell glutathione peroxidase-1 activity, and prior radiation therapy.
Diagnosis: Differential Diagnosis
Nonischemic cardiovascular causes include aortic dissection and pericarditis. Pulmonary causes include pulmonary embolism, pneumothorax, pneumonia, and pleuritis. Gastrointestinal causes include esophageal disorders (esophagitis, spasm, reflux), biliary colic, cholecystitis, choledocholithiasis, cholangitis, peptic ulcer disease, pancreatitis, and other upper GI pathology. Chest wall causes include costochondritis, fibrositis, rib fracture, sternoclavicular arthritis, and herpes zoster before rash onset. Psychiatric causes include anxiety disorders, hyperventilation, panic disorder, primary anxiety, affective disorders (including depression), somatoform disorders, and thought disorders such as fixed delusions.
Workup and Clinical Risk Assessment
In patients with chest pain, estimate the probability of coronary artery disease based on age, sex, cardiovascular risk factors, and pain characteristics. History is the most important diagnostic element: exertional chest or left arm discomfort relieved by rest in a patient with risk factors strongly suggests coronary disease. Chest pain is categorized as typical angina, atypical angina, or noncardiac chest pain. Typical (definite) angina includes all three: substernal discomfort with characteristic quality and duration, provoked by exertion or emotional stress, and relieved by rest and/or sublingual nitroglycerin. Atypical (probable) angina has two of these features. Noncardiac chest pain has one or none.
Physical examination may be normal, but findings such as hypertension, arcus senilis, xanthelasma, carotid or peripheral bruits, and a prominent S4 increase suspicion for coronary artery disease. A mitral regurgitation murmur may indicate ischemic cardiomyopathy or transient ischemia, while murmurs of hypertrophic cardiomyopathy or aortic stenosis suggest non-CAD causes of angina. The overall evaluation aims to identify high-risk coronary disease while minimizing resource use. A practical approach considers (1) coronary risk assessment using classic risk factors, (2) functional capacity and stress test results, (3) left and right ventricular function, and (4) coronary anatomy, recognizing not every patient needs every modality. Patients without known coronary artery disease are typically stratified into low, intermediate, or high pretest probability after considering comorbidities and atherosclerotic risk; functional capacity and stress testing (exercise tolerance test, exercise testing with myocardial perfusion imaging, or stress echocardiography) are emphasized for low-to-intermediate probability groups. Exercise testing is preferred when feasible. Stress results help estimate annual mortality risk: <1% low risk, 1%–3% intermediate and>3% high risk.
Laboratory Tests and ECG/Imaging Basics
Screen for hypertension, diabetes, and hyperlipidemia per routine guidelines. Obtain an ECG during pain and when the patient is symptom-free; a normal resting ECG can occur in stable ischemic heart disease, and a small percentage of acute MI patients may have a normal or nondiagnostic ECG. Chest x-ray (PA and lateral) is considered when symptoms suggest heart failure, pericardial disease, or aortic aneurysm/dissection. High-sensitivity CRP (cardio-CRP) is a moderate predictor of coronary disease and adds prognostic value beyond the Framingham risk score.
Exercise Testing and Stress Imaging
Exercise testing is used for diagnosis and prognosis and provides important prognostic information via exercise performance and hemodynamic response. It is most useful in intermediate-likelihood patients because low-likelihood patients can have false positives and high-likelihood patients can have false negatives. The treadmill test is contraindicated when baseline ECG abnormalities make interpretation unreliable, including ST depression >0.5 mm, Wolff-Parkinson-White syndrome, left bundle branch block, or pacemaker rhythm. If baseline ECG abnormalities prevent interpretation, use stress echocardiography or myocardial perfusion imaging. Stress echocardiography tends to have higher specificity and lower cost, whereas radionuclide perfusion imaging has higher sensitivity (notably for single-vessel disease) and higher technical success. If the patient cannot exercise adequately, pharmacologic stress testing (e.g., dobutamine, adenosine, regadenoson) can be paired with these imaging modalities.
Risk Stratification From Noninvasive Testing
High risk (>3% annual risk of death or MI) includes severe resting LV dysfunction (LVEF <35%) not explained by noncoronary causes; resting perfusion abnormalities involving ≥10% of myocardium without prior mi; high-risk stress ecg findings such as ≥2 mm st depression at low workload or persisting into recovery, exercise-induced elevation, ventricular tachycardia />ibrillation; severe stress-induced LV dysfunction (peak exercise LVEF <45% or lvef drop ≥10%); stress-induced perfusion abnormalities involving ≥10% of myocardium multiple vascular territories; lv dilation; inducible wall motion abnormality>2 segments or two coronary beds; wall motion abnormality at low-dose dobutamine (≤10 mg/kg/min) or low heart rate (<120 bpm); and multivessel obstructive cad (≥70%) or left main stenosis (≥50%) on coronary cta.< />pan>
Intermediate risk (1%–3% annual risk) includes mild-to-moderate resting LV dysfunction (LVEF 35%–49%); resting perfusion abnormalities involving 5%–9.9% without prior MI; ≥1 mm ST depression with exertional symptoms; stress perfusion abnormalities involving 5%–9.9% or one vascular territory without LV dilation; small wall motion abnormality involving 1–2 segments and one coronary bed; and single-vessel CAD ≥70% or moderate stenosis (50%–69%) in ≥2 arteries on coronary CTA. Low risk (<1% annual risk) includes a low-risk treadmill score (≥5) or no new st changes exercise-induced chest pain at maximal exercise; normal small perfusion defect involving <5% of myocardium; stress change in limited resting wall motion abnormalities with stress; and coronary stenosis>50% on coronary CTA (noting these “low-risk” findings may not indicate truly low risk if a high-risk treadmill score or severe resting LV dysfunction is present). Coronary artery calcium assessment may also contribute to risk stratification.
A useful predictor in stable angina is the Duke treadmill score, combining exercise time/METS (Bruce protocol), ST-segment depression in millimeters, and an angina index; favorable scores (>5) are associated with >97% five-year survival independent of coronary anatomy and LV function.
Echocardiography, Coronary CTA, Calcium Scoring, Cardiac MRI, and Invasive Angiography
Echocardiography is indicated when murmurs suggest aortic stenosis, hypertrophic cardiomyopathy, mitral regurgitation, or mitral valve prolapse, and in patients with prior MI, pathologic Q waves, complex ventricular arrhythmias, heart failure, hypertension, diabetes, or abnormal ECG. Coronary CT angiography (CCTA) can detect subclinical CAD in asymptomatic patients with intermediate 10-year Framingham risk (10%–20%) and is recommended by 2021 ACC/AHA/ASE chest pain guidelines as a front-line imaging modality for stable angina. Studies comparing CCTA to invasive coronary angiography in stable angina show similar outcomes but fewer procedural complications and fewer invasive angiograms with an initial CCTA strategy. CCTA evaluates coronary calcium, lumen, and vessel wall; it can be first-line for risk assessment when a patient cannot exercise adequately, can clarify indeterminate functional tests, and can assess bypass graft or large stent patency (>3 mm). Cost and radiation limit routine broad use. CCTA has high negative predictive value to rule out severe CAD during ED chest pain evaluation (ROMICAT-II), and the SCOT-HEART trial (2018) showed coronary CTA lowered nonfatal MI risk compared with standard care alone in stable angina. Myocardial perfusion imaging and noninvasive fractional flow reserve can also be derived from cardiac CTA in selected settings.
Coronary artery calcium scoring provides strong predictive value beyond standard risk factors in low-to-intermediate pretest probability patients; a score <100 suggests low risk, while>400 suggests high risk. Cardiac MRI, beyond diagnosing arrhythmogenic right ventricular dysplasia, can assess perfusion, viability, and function in patients unable to exercise, though further cost-effectiveness data are needed in ischemic cardiomyopathy. Invasive coronary angiography remains the gold standard to define clinically significant CAD and is used to map location and extent of disease, especially in patients being considered for revascularization (CABG or angioplasty).
Treatment Overview: Core Strategies
Management involves five overlapping strategies: patient education and shared decision-making; management of comorbid conditions that worsen stable ischemic heart disease; aggressive modification of preventable risk factors (smoking cessation, weight loss in obesity, regular aerobic exercise 30–60 minutes/day for 5 days/week, folate deficiency correction, limiting saturated fat to <7% of calories and trans fats to <1%, low-sodium diet <2 g />ay, and emphasizing medication adherence); evidence-based pharmacologic therapy to improve symptoms and survival; and appropriate revascularization for selected patients to improve survival and long-term outcomes.
Pharmacologic Therapy (Prevention of MI/Death and Symptom Control)
Aspirin reduces cardiovascular mortality and morbidity by about 20%–25% in CAD; the usual dose is 75–162 mg/day if no contraindication. It inhibits cyclooxygenase and thromboxane A2 and reduces adverse cardiovascular events; patients intolerant of aspirin may use clopidogrel or undergo aspirin desensitization. Clopidogrel irreversibly blocks the P2Y12 ADP receptor, reducing platelet activation and aggregation; it can be used alone for aspirin intolerance or combined with aspirin in high-risk stable ischemic heart disease patients with low bleeding risk; dose is 75 mg/day. Ticagrelor (PEGASUS-TIMI 54) reduced death, cardiovascular MI, or stroke in patients after one year post-MI but increases bleeding risk versus placebo. Dipyridamole is not recommended as antiplatelet therapy in stable ischemic heart disease.
Beta-blockers are first-line for stable angina and have proven benefits in preventing MI and death. They reduce myocardial oxygen demand by lowering heart rate, blood pressure, AV nodal conduction, and contractility, raising the ischemic threshold and decreasing angina frequency. Doses are generally adjusted to achieve a resting heart rate of 55–60 bpm. Beta-blockers are recommended for at least 2–3 years after MI and lifelong for patients with LVEF <40% with heart failure or prior mi.< />pan>
Nitrates cause venodilation and vascular smooth muscle relaxation, decreasing preload (and myocardial oxygen consumption) and reducing resistance across obstructed segments, while redistributing coronary flow by augmenting collateral circulation and lowering LV diastolic pressure; they also have antithrombotic and antiplatelet effects. Sublingual nitroglycerin or spray should be prescribed for immediate angina relief in stable ischemic heart disease. Nitrate tolerance can be minimized with a daily nitrate-free interval (e.g., omit bedtime oral isosorbide dinitrate or use a 12-hour on/12-hour off transdermal schedule). Nitrates are relatively contraindicated in hypertrophic obstructive cardiomyopathy and should be avoided in severe aortic stenosis. They must not be used within 24 hours of sildenafil or vardenafil, or within 48 hours of tadalafil because of hypotension risk.
Calcium channel blockers improve oxygen supply by lowering coronary resistance and increasing arterial flow and reduce demand by lowering contractility and systemic vascular resistance; however, they have no proven mortality benefit in stable ischemic heart disease. They are first-line when beta-blockers are contraindicated, are key in coronary spasm, and are effective in microvascular angina. All classes reduce angina episodes, increase exercise duration, and reduce nitroglycerin use in effort-induced angina, but short-acting agents should be avoided. Nondihydropyridine calcium channel blockers should generally be avoided in systolic heart failure due to negative inotropy.
Ranolazine (studied in MARISA, CARISA, RAN080, ERICA; total ~1737 patients) inhibits the late inward sodium current, indirectly reducing sodium-dependent calcium influx during ischemia and improving diastolic tension and oxygen consumption. Its antianginal effects do not depend on heart rate or blood pressure reduction and it is used for chronic angina inadequately controlled by other agents, either as an alternative or in combination. It can prolong the QT interval, and low doses of diltiazem or verapamil should be used if combined.
ACE inhibitors may reduce LV/vascular hypertrophy, slow atherosclerosis progression, reduce plaque rupture/thrombosis risk, and improve hemodynamics and oxygen balance. They reduce cardiovascular death, MI, and stroke in at-risk patients or those with vascular disease, and are indicated in stable ischemic heart disease patients with hypertension, diabetes, LVEF <40%, or chronic kidney disease. arbs are alternatives for ace-intolerant patients who qualify.< />pan>
High-intensity statins are recommended for all patients with CAD. The ACC has recommended an LDL goal <70 mg />L for secondary prevention (no LDL goal for primary prevention). PCSK9 inhibitors (alirocumab, evolocumab) are approved for heterozygous familial hypercholesterolemia and are considered in very-high-risk atherosclerotic cardiovascular disease patients not at LDL goal despite high-intensity statin plus ezetimibe; ezetimibe should generally be tried before PCSK9 inhibitors due to cost. Inclisiran, evinacumab, and bempedoic acid are reasonable nonstatin options for patients unable to tolerate statins or reach LDL targets. Annual influenza vaccination is recommended in stable ischemic heart disease to reduce mortality, morbidity, and hospitalization. In type 2 diabetes, major trials (EMPA-REG OUTCOME, CANVAS, DECLARE-TIMI 58, CREDENCE) show SGLT2 inhibitors reduce cardiovascular events.
Newer and Adjunct Modalities for Chronic Stable Angina
Despite progress with PCI and CABG, some patients need additional therapies for symptom relief and quality of life, especially those with diffuse CAD unsuitable for revascularization, multiple prior PCIs/CABG, lack of bypass conduits, severe LV systolic dysfunction after revascularization, or comorbidities making procedures high risk. Pharmacologic agents explored as adjuncts to standard therapy (nitrates, beta-blockers, calcium channel blockers, ranolazine) include high-dose statins, trimetazidine, perhexiline, nicorandil, allopurinol, ivabradine, fasudil, and testosterone. Experimental nonpharmacologic options include stem cell therapy, therapeutic angiogenesis, and mechanical therapies such as enhanced external counterpulsation, spinal cord stimulation, transmyocardial laser revascularization, and coronary sinus reducing devices.
In TACT, EDTA chelation infusions reduced a composite outcome (including mortality, recurrent MI, stroke, revascularization, or angina hospitalization), leading chelation therapy to be upgraded from Class III (not recommended) to Class IIb in 2014 stable ischemic heart disease guidelines. Allopurinol (xanthine oxidase inhibitor) at 600 mg daily for 6 weeks in a small crossover study of 65 heart failure patients increased median time to ST depression (232 to 393 seconds), but larger studies are needed before recommending it routinely. Testosterone may improve endothelial dysfunction and potentially angina, but safety concerns require more trials. EECP was assessed in MUST-EECP (139 outpatients randomized to 35 hours active EECP), showing it was well tolerated; exercise duration rose in both groups; active EECP increased time to 1-mm ST depression while inactive did not; and more active EECP patients had fewer angina episodes. Professional society updates state EECP may be considered for refractory angina. Treatments not shown to reduce cardiovascular risk or improve outcomes include estrogen therapy; vitamin C, vitamin E, beta-carotene supplementation; folate/B6/B12 therapy solely to lower homocysteine; chelation therapy (outside its limited guideline context); garlic; coenzyme Q10; selenium; and chromium.
Referral and Revascularization
Revascularization strategy is chosen to improve survival and/or symptoms and includes PCI (balloon angioplasty and stenting) or CABG. While PCI is clearly beneficial in acute MI, its role in stable CAD is less clear; PCI use for stable CAD fell substantially from 2007 to 2011, especially in high-volume PCI hospitals.
To improve survival, CABG is recommended for significant left main stenosis (>50%), proximal LAD stenosis >70%, three-vessel disease with >70% stenosis, or two-vessel disease with severe/extensive ischemia, and for patients with mild-to-moderate LV systolic dysfunction (EF 35%–50%) with significant multivessel CAD. A left internal mammary artery graft to the LAD improves survival. CABG is preferred over PCI to improve survival in multivessel CAD with SYNTAX score >22 and in multivessel CAD with diabetes, particularly when LIMA-to-LAD grafting is used. PCI may be a reasonable alternative to CABG in selected stable patients with unprotected left main CAD when SYNTAX is low-to-intermediate and/or surgical risk is high (e.g., STS operative mortality risk >5%), PCI procedural complication risk is low, and likelihood of good long-term outcome is high.
To improve symptoms, CABG or PCI can be beneficial for patients with one or more significant (>70%) stenoses amenable to revascularization who have unacceptable angina despite maximal medical therapy, or when medications cannot be intensified due to contraindications, adverse effects, or patient preference. The ORBITA trial (2017) showed no significant improvement in angina score after PCI in optimally treated stable angina, though most placebo-group patients later underwent PCI. The ISCHEMIA trial (2020) showed no benefit of routine invasive therapy over conservative treatment in moderate-to-severe ischemia, but excluded patients with acute coronary syndrome, severe/frequent symptoms, EF <35%, and left main stenosis. hybrid revascularization (lima-to-lad grafting plus pci to non-lad vessels) may be used when the aorta is unfavorable, cabg targets are poor, conduits unsuitable, or lad anatomy unfavorable for pci. compared with pci, provides more effective angina relief fewer repeat procedures but carries a higher procedural stroke risk; 10-year survival similar.< />pan>
PCI is widely used for symptom relief but is not superior to intensive medical therapy in preventing MI or death in stable patients. Candidates for PCI should also be candidates for CABG. About 80% experience immediate symptom benefit after PCI. Stents are used in the majority of PCI cases and reduce restenosis when used electively in atheromatous lesions. Key limitations of stenting include subacute thrombosis, in-stent restenosis, bleeding risk from antiplatelet therapy, and higher cost. Dual antiplatelet therapy (aspirin plus a P2Y12 inhibitor) prevents stent thrombosis; duration depends on stent type—about 4 weeks for bare metal stents and generally 6–12 months for drug-eluting stents due to delayed endothelialization. Newer drug-eluting stents with thin struts and limus-family drugs from durable polymers reduce stent thrombosis risk compared with early-generation sirolimus- or paclitaxel-eluting stents. Current evidence supports drug-eluting stents in most settings unless dual antiplatelet therapy is contraindicated.
Pearls and Considerations
Although nitrate responsiveness has traditionally been part of the diagnostic approach for stable ischemic heart disease, some evidence suggests that relief after nitroglycerin does not reliably predict active coronary artery disease in general chest pain admissions and should not be used alone to guide acute diagnosis. CABG offers higher long-term survival and fewer repeat revascularizations than PCI in some populations, but many patients prefer stenting because it is less invasive, involves shorter hospitalization, and has lower in-hospital mortality.
Basic Information
Angina pectoris is a clinical syndrome of discomfort in the chest, jaw, shoulder, back, or arm caused by myocardial ischemia. Most commonly it is related to atherosclerotic (atheromatous) plaque in one or more large epicardial coronary arteries, but ischemia can also occur without obstructive coronary artery disease. Nonobstructive causes include uncontrolled hypertension, microvascular disease, valvular heart disease, hypertrophic cardiomyopathy, coronary spasm, and endothelial dysfunction. In general, any condition that creates an imbalance between myocardial oxygen supply and demand can produce an angina syndrome.
Classification of Angina
Chronic stable angina (also termed stable ischemic heart disease or chronic coronary artery disease) is typically predictable and follows a precipitating event such as climbing stairs, sexual intercourse, a heavy meal, emotional stress, or cold weather. Episodes usually resemble prior attacks in severity and are relieved by rest or the patient’s customary dose of sublingual nitroglycerin. It is usually caused by fixed coronary obstruction from atherosclerosis, commonly with one or more major coronary stenoses, often >70%. Unstable angina includes rest angina, recent-onset angina, and crescendo angina and is addressed under acute coronary syndrome. Rest angina occurs at rest, is usually prolonged (>20 minutes), and occurs within 1 week of presentation. Recent-onset angina is angina of at least Canadian Cardiovascular Society (CCS) Class III severity beginning within the past 2 months. Crescendo angina is previously diagnosed angina that becomes more frequent, lasts longer, or occurs at a lower threshold, defined as worsening by more than one CCS class within 2 months to at least CCS Class III severity.
Prinzmetal (variant) angina occurs at rest, is commonly triggered after cold exposure, and tends to be cyclical. It is associated with episodic ST-segment elevations on ECG and is due to coronary artery spasm with or without superimposed coronary artery disease; these patients are more prone to ventricular arrhythmias. Microvascular angina (syndrome X) refers to patients with angina symptoms, a positive exercise test, normal coronary angiograms, and no coronary spasm. In this condition, defective endothelium-dependent dilation in the coronary microcirculation contributes to abnormal regulation of myocardial perfusion and ischemic symptoms. Patients with chest pain and normal or nonobstructive coronary angiograms are predominantly women, and prognosis may be less benign than often assumed, with about a 2% risk of death or myocardial infarction at 30 days.
Refractory angina describes patients who, despite optimal medical therapy using at least maximal tolerated doses of two antianginal medications (plus aspirin and intensive risk-factor modification such as smoking cessation and tight control of hypertension, diabetes, and hyperlipidemia), continue to have angina along with objective evidence of ischemia. Other causes of angina syndromes include angina due to aortic stenosis, idiopathic hypertrophic subaortic stenosis, and cocaine-induced coronary vasoconstriction.
Functional Classification (Canadian Cardiovascular Society, CCS)
Class I: ordinary physical activity (walking, climbing stairs) does not cause angina; symptoms occur only with strenuous, rapid, or prolonged exertion at work or recreation. Class II: slight limitation of ordinary activity; angina occurs with walking or climbing stairs rapidly, walking uphill, activity after meals, exposure to cold or wind, emotional stress, or during the first few hours after awakening; angina occurs when walking more than two level blocks or climbing more than one flight of ordinary stairs at a normal pace in normal conditions. Class III: marked limitation of ordinary physical activity; angina occurs with walking one to two level blocks or climbing one flight of stairs in normal conditions at a normal pace. Class IV: inability to carry on any physical activity without discomfort; anginal symptoms may be present at rest.
ICD-10-CM Codes
I20.1 Angina pectoris with documented spasm; I20.8 Other forms of angina pectoris; I20.9 Angina pectoris, unspecified. I25.110 Atherosclerotic heart disease of native coronary artery with unstable angina pectoris; I25.111 Atherosclerotic heart disease of native coronary artery with angina pectoris with documented spasm; I25.118 Atherosclerotic heart disease of native coronary artery with other forms of angina pectoris; I25.119 Atherosclerotic heart disease of native coronary artery with unspecified angina pectoris. I25.700 Atherosclerosis of coronary artery bypass graft(s), unspecified, with unstable angina pectoris; I25.790 Atherosclerosis of other coronary artery bypass graft(s) with unstable angina pectoris; I25.791 Atherosclerosis of other coronary artery bypass graft(s) with angina pectoris with documented spasm; I25.798 Atherosclerosis of other coronary artery bypass graft(s) with other forms of angina pectoris; I25.799 Atherosclerosis of other coronary artery bypass graft(s) with unspecified angina pectoris.
Epidemiology and Demographics
Approximately one in three adults in the United States (about 81 million) has some form of cardiovascular disease. Based on NHANES 2007–2010, an estimated 15.4 million people have coronary heart disease, and about 7.8 million have angina. Angina is most common in middle-aged and elderly men. Among persons aged 60–79 years, roughly 25% of men and 16% of women have coronary heart disease; among those older than 80 years, the figures rise to about 37% for men and 23% for women. After menopause, the incidence of coronary heart disease and angina in women becomes similar to that in men. Even with improving survival over time, stable ischemic heart disease remains the leading cause of death in men and women (about 27% of deaths). Angina is the initial manifestation of ischemic heart disease in about 50% of cases, and about half of patients who present with acute coronary syndrome report preceding angina. Older population-based studies (Olmstead County, MN and Framingham, MA) reported an annual myocardial infarction rate of about 3%–3.5% per year among patients with symptomatic angina. Within 12 months of stable angina diagnosis, about 10%–20% progress to myocardial infarction or unstable angina.
Physical Findings and Clinical Presentation
Evaluating chest pain requires attention to quality, location, severity, duration, radiation, associated symptoms, provoking factors, and relieving factors. Anginal pain is often described as squeezing, griplike, suffocating, or heavy; it is rarely sharp or stabbing and typically does not change with position or respiration. The classic Levine sign is a clenched fist placed over the precordium. Many patients describe angina not as “pain” but as tightness, pressure, or discomfort. Atypical presentations are more common in women and older adults and may include nausea, vomiting, midepigastric discomfort, sharp (atypical) chest pain, dizziness, or syncope. Ischemic discomfort lasting longer than 20 minutes should raise concern for acute coronary syndrome. Women are more likely than men to report atypical chest pain or discomfort (reported by 65% in the WISE study). Elderly patients and those with diabetes may present with non–chest pain symptoms such as dyspnea, fatigue, or diaphoresis.
Etiology and Risk Factors
Key risk factors include advanced age, male sex, and genetic predisposition such as a family history of premature coronary artery disease in first-degree relatives (men <55 years, women <65 years). smoking increases the risk of first myocardial infarction nearly threefold. other major risks include hypertension, hyperlipidemia, impaired glucose tolerance or diabetes mellitus, prior stroke peripheral arterial disease, chronic kidney metabolic syndrome, physical inactivity, and obesity (bmi>30% over ideal). Higher childhood BMI is also associated with increased adult coronary heart disease risk.
Several conditions increase myocardial oxygen demand, including hyperthermia (especially with volume contraction), hyperthyroidism, and cocaine or methamphetamine use. Cocaine is used regularly by more than 5 million Americans and leads to over 64,000 emergency department evaluations yearly to rule out myocardial ischemia; it causes sympathomimetic toxicity, increases oxygen demand, induces coronary vasospasm, and can cause infarction in young patients, while long-term use accelerates stable ischemic heart disease. Severe uncontrolled hypertension increases myocardial oxygen demand and reduces subendocardial perfusion by increasing left ventricular wall tension; hypertrophic cardiomyopathy and aortic stenosis can produce even more severe hypertrophy and wall tension. Ventricular or supraventricular tachycardias can also raise oxygen demand and may require ambulatory monitoring for diagnosis.
Reduced oxygen supply can trigger angina as well. Anemia may cause angina when hemoglobin falls below about 9 g/dL, and ST–T changes (depression or inversion) can occur at hemoglobin levels below about 7 g/dL. Hypoxemia from pulmonary disease such as pneumonia, asthma, COPD, pulmonary hypertension, interstitial fibrosis, or obstructive sleep apnea can precipitate angina. Additional associated conditions and exposures include polycythemia, leukemia, thrombocytosis, hypergammaglobulinemia, oral contraceptive or hormone replacement therapy use, coronary artery calcium (linked to higher MI risk), long-term NSAID use, and traffic-related air pollution (dilute diesel exhaust), which promotes ischemia and adverse cardiovascular events. Low serum folate (needed to convert homocysteine to methionine) is associated with increased fatal coronary heart disease risk; hyperhomocysteinemia damages endothelium and promotes arterial smooth muscle proliferation and is an independent risk factor for coronary events, particularly in type 2 diabetes. Elevated high-sensitivity C-reactive protein (cardio-CRP) reflects systemic inflammation and is linked to accelerated atherosclerosis. Other noted associations include depression, vasculitis, elevated lipoprotein-associated phospholipase A2, elevated fibrinogen, low red blood cell glutathione peroxidase-1 activity, and prior radiation therapy.
Diagnosis: Differential Diagnosis
Nonischemic cardiovascular causes include aortic dissection and pericarditis. Pulmonary causes include pulmonary embolism, pneumothorax, pneumonia, and pleuritis. Gastrointestinal causes include esophageal disorders (esophagitis, spasm, reflux), biliary colic, cholecystitis, choledocholithiasis, cholangitis, peptic ulcer disease, pancreatitis, and other upper GI pathology. Chest wall causes include costochondritis, fibrositis, rib fracture, sternoclavicular arthritis, and herpes zoster before rash onset. Psychiatric causes include anxiety disorders, hyperventilation, panic disorder, primary anxiety, affective disorders (including depression), somatoform disorders, and thought disorders such as fixed delusions.
Workup and Clinical Risk Assessment
In patients with chest pain, estimate the probability of coronary artery disease based on age, sex, cardiovascular risk factors, and pain characteristics. History is the most important diagnostic element: exertional chest or left arm discomfort relieved by rest in a patient with risk factors strongly suggests coronary disease. Chest pain is categorized as typical angina, atypical angina, or noncardiac chest pain. Typical (definite) angina includes all three: substernal discomfort with characteristic quality and duration, provoked by exertion or emotional stress, and relieved by rest and/or sublingual nitroglycerin. Atypical (probable) angina has two of these features. Noncardiac chest pain has one or none.
Physical examination may be normal, but findings such as hypertension, arcus senilis, xanthelasma, carotid or peripheral bruits, and a prominent S4 increase suspicion for coronary artery disease. A mitral regurgitation murmur may indicate ischemic cardiomyopathy or transient ischemia, while murmurs of hypertrophic cardiomyopathy or aortic stenosis suggest non-CAD causes of angina. The overall evaluation aims to identify high-risk coronary disease while minimizing resource use. A practical approach considers (1) coronary risk assessment using classic risk factors, (2) functional capacity and stress test results, (3) left and right ventricular function, and (4) coronary anatomy, recognizing not every patient needs every modality. Patients without known coronary artery disease are typically stratified into low, intermediate, or high pretest probability after considering comorbidities and atherosclerotic risk; functional capacity and stress testing (exercise tolerance test, exercise testing with myocardial perfusion imaging, or stress echocardiography) are emphasized for low-to-intermediate probability groups. Exercise testing is preferred when feasible. Stress results help estimate annual mortality risk: <1% low risk, 1%–3% intermediate and>3% high risk.
Laboratory Tests and ECG/Imaging Basics
Screen for hypertension, diabetes, and hyperlipidemia per routine guidelines. Obtain an ECG during pain and when the patient is symptom-free; a normal resting ECG can occur in stable ischemic heart disease, and a small percentage of acute MI patients may have a normal or nondiagnostic ECG. Chest x-ray (PA and lateral) is considered when symptoms suggest heart failure, pericardial disease, or aortic aneurysm/dissection. High-sensitivity CRP (cardio-CRP) is a moderate predictor of coronary disease and adds prognostic value beyond the Framingham risk score.
Exercise Testing and Stress Imaging
Exercise testing is used for diagnosis and prognosis and provides important prognostic information via exercise performance and hemodynamic response. It is most useful in intermediate-likelihood patients because low-likelihood patients can have false positives and high-likelihood patients can have false negatives. The treadmill test is contraindicated when baseline ECG abnormalities make interpretation unreliable, including ST depression >0.5 mm, Wolff-Parkinson-White syndrome, left bundle branch block, or pacemaker rhythm. If baseline ECG abnormalities prevent interpretation, use stress echocardiography or myocardial perfusion imaging. Stress echocardiography tends to have higher specificity and lower cost, whereas radionuclide perfusion imaging has higher sensitivity (notably for single-vessel disease) and higher technical success. If the patient cannot exercise adequately, pharmacologic stress testing (e.g., dobutamine, adenosine, regadenoson) can be paired with these imaging modalities.
Risk Stratification From Noninvasive Testing
High risk (>3% annual risk of death or MI) includes severe resting LV dysfunction (LVEF <35%) not explained by noncoronary causes; resting perfusion abnormalities involving ≥10% of myocardium without prior mi; high-risk stress ecg findings such as ≥2 mm st depression at low workload or persisting into recovery, exercise-induced elevation, ventricular tachycardia />ibrillation; severe stress-induced LV dysfunction (peak exercise LVEF <45% or lvef drop ≥10%); stress-induced perfusion abnormalities involving ≥10% of myocardium multiple vascular territories; lv dilation; inducible wall motion abnormality>2 segments or two coronary beds; wall motion abnormality at low-dose dobutamine (≤10 mg/kg/min) or low heart rate (<120 bpm); and multivessel obstructive cad (≥70%) or left main stenosis (≥50%) on coronary cta.< />pan>
Intermediate risk (1%–3% annual risk) includes mild-to-moderate resting LV dysfunction (LVEF 35%–49%); resting perfusion abnormalities involving 5%–9.9% without prior MI; ≥1 mm ST depression with exertional symptoms; stress perfusion abnormalities involving 5%–9.9% or one vascular territory without LV dilation; small wall motion abnormality involving 1–2 segments and one coronary bed; and single-vessel CAD ≥70% or moderate stenosis (50%–69%) in ≥2 arteries on coronary CTA. Low risk (<1% annual risk) includes a low-risk treadmill score (≥5) or no new st changes exercise-induced chest pain at maximal exercise; normal small perfusion defect involving <5% of myocardium; stress change in limited resting wall motion abnormalities with stress; and coronary stenosis>50% on coronary CTA (noting these “low-risk” findings may not indicate truly low risk if a high-risk treadmill score or severe resting LV dysfunction is present). Coronary artery calcium assessment may also contribute to risk stratification.
A useful predictor in stable angina is the Duke treadmill score, combining exercise time/METS (Bruce protocol), ST-segment depression in millimeters, and an angina index; favorable scores (>5) are associated with >97% five-year survival independent of coronary anatomy and LV function.
Echocardiography, Coronary CTA, Calcium Scoring, Cardiac MRI, and Invasive Angiography
Echocardiography is indicated when murmurs suggest aortic stenosis, hypertrophic cardiomyopathy, mitral regurgitation, or mitral valve prolapse, and in patients with prior MI, pathologic Q waves, complex ventricular arrhythmias, heart failure, hypertension, diabetes, or abnormal ECG. Coronary CT angiography (CCTA) can detect subclinical CAD in asymptomatic patients with intermediate 10-year Framingham risk (10%–20%) and is recommended by 2021 ACC/AHA/ASE chest pain guidelines as a front-line imaging modality for stable angina. Studies comparing CCTA to invasive coronary angiography in stable angina show similar outcomes but fewer procedural complications and fewer invasive angiograms with an initial CCTA strategy. CCTA evaluates coronary calcium, lumen, and vessel wall; it can be first-line for risk assessment when a patient cannot exercise adequately, can clarify indeterminate functional tests, and can assess bypass graft or large stent patency (>3 mm). Cost and radiation limit routine broad use. CCTA has high negative predictive value to rule out severe CAD during ED chest pain evaluation (ROMICAT-II), and the SCOT-HEART trial (2018) showed coronary CTA lowered nonfatal MI risk compared with standard care alone in stable angina. Myocardial perfusion imaging and noninvasive fractional flow reserve can also be derived from cardiac CTA in selected settings.
Coronary artery calcium scoring provides strong predictive value beyond standard risk factors in low-to-intermediate pretest probability patients; a score <100 suggests low risk, while>400 suggests high risk. Cardiac MRI, beyond diagnosing arrhythmogenic right ventricular dysplasia, can assess perfusion, viability, and function in patients unable to exercise, though further cost-effectiveness data are needed in ischemic cardiomyopathy. Invasive coronary angiography remains the gold standard to define clinically significant CAD and is used to map location and extent of disease, especially in patients being considered for revascularization (CABG or angioplasty).
Treatment Overview: Core Strategies
Management involves five overlapping strategies: patient education and shared decision-making; management of comorbid conditions that worsen stable ischemic heart disease; aggressive modification of preventable risk factors (smoking cessation, weight loss in obesity, regular aerobic exercise 30–60 minutes/day for 5 days/week, folate deficiency correction, limiting saturated fat to <7% of calories and trans fats to <1%, low-sodium diet <2 g />ay, and emphasizing medication adherence); evidence-based pharmacologic therapy to improve symptoms and survival; and appropriate revascularization for selected patients to improve survival and long-term outcomes.
Pharmacologic Therapy (Prevention of MI/Death and Symptom Control)
Aspirin reduces cardiovascular mortality and morbidity by about 20%–25% in CAD; the usual dose is 75–162 mg/day if no contraindication. It inhibits cyclooxygenase and thromboxane A2 and reduces adverse cardiovascular events; patients intolerant of aspirin may use clopidogrel or undergo aspirin desensitization. Clopidogrel irreversibly blocks the P2Y12 ADP receptor, reducing platelet activation and aggregation; it can be used alone for aspirin intolerance or combined with aspirin in high-risk stable ischemic heart disease patients with low bleeding risk; dose is 75 mg/day. Ticagrelor (PEGASUS-TIMI 54) reduced death, cardiovascular MI, or stroke in patients after one year post-MI but increases bleeding risk versus placebo. Dipyridamole is not recommended as antiplatelet therapy in stable ischemic heart disease.
Beta-blockers are first-line for stable angina and have proven benefits in preventing MI and death. They reduce myocardial oxygen demand by lowering heart rate, blood pressure, AV nodal conduction, and contractility, raising the ischemic threshold and decreasing angina frequency. Doses are generally adjusted to achieve a resting heart rate of 55–60 bpm. Beta-blockers are recommended for at least 2–3 years after MI and lifelong for patients with LVEF <40% with heart failure or prior mi.< />pan>
Nitrates cause venodilation and vascular smooth muscle relaxation, decreasing preload (and myocardial oxygen consumption) and reducing resistance across obstructed segments, while redistributing coronary flow by augmenting collateral circulation and lowering LV diastolic pressure; they also have antithrombotic and antiplatelet effects. Sublingual nitroglycerin or spray should be prescribed for immediate angina relief in stable ischemic heart disease. Nitrate tolerance can be minimized with a daily nitrate-free interval (e.g., omit bedtime oral isosorbide dinitrate or use a 12-hour on/12-hour off transdermal schedule). Nitrates are relatively contraindicated in hypertrophic obstructive cardiomyopathy and should be avoided in severe aortic stenosis. They must not be used within 24 hours of sildenafil or vardenafil, or within 48 hours of tadalafil because of hypotension risk.
Calcium channel blockers improve oxygen supply by lowering coronary resistance and increasing arterial flow and reduce demand by lowering contractility and systemic vascular resistance; however, they have no proven mortality benefit in stable ischemic heart disease. They are first-line when beta-blockers are contraindicated, are key in coronary spasm, and are effective in microvascular angina. All classes reduce angina episodes, increase exercise duration, and reduce nitroglycerin use in effort-induced angina, but short-acting agents should be avoided. Nondihydropyridine calcium channel blockers should generally be avoided in systolic heart failure due to negative inotropy.
Ranolazine (studied in MARISA, CARISA, RAN080, ERICA; total ~1737 patients) inhibits the late inward sodium current, indirectly reducing sodium-dependent calcium influx during ischemia and improving diastolic tension and oxygen consumption. Its antianginal effects do not depend on heart rate or blood pressure reduction and it is used for chronic angina inadequately controlled by other agents, either as an alternative or in combination. It can prolong the QT interval, and low doses of diltiazem or verapamil should be used if combined.
ACE inhibitors may reduce LV/vascular hypertrophy, slow atherosclerosis progression, reduce plaque rupture/thrombosis risk, and improve hemodynamics and oxygen balance. They reduce cardiovascular death, MI, and stroke in at-risk patients or those with vascular disease, and are indicated in stable ischemic heart disease patients with hypertension, diabetes, LVEF <40%, or chronic kidney disease. arbs are alternatives for ace-intolerant patients who qualify.< />pan>
High-intensity statins are recommended for all patients with CAD. The ACC has recommended an LDL goal <70 mg />L for secondary prevention (no LDL goal for primary prevention). PCSK9 inhibitors (alirocumab, evolocumab) are approved for heterozygous familial hypercholesterolemia and are considered in very-high-risk atherosclerotic cardiovascular disease patients not at LDL goal despite high-intensity statin plus ezetimibe; ezetimibe should generally be tried before PCSK9 inhibitors due to cost. Inclisiran, evinacumab, and bempedoic acid are reasonable nonstatin options for patients unable to tolerate statins or reach LDL targets. Annual influenza vaccination is recommended in stable ischemic heart disease to reduce mortality, morbidity, and hospitalization. In type 2 diabetes, major trials (EMPA-REG OUTCOME, CANVAS, DECLARE-TIMI 58, CREDENCE) show SGLT2 inhibitors reduce cardiovascular events.
Newer and Adjunct Modalities for Chronic Stable Angina
Despite progress with PCI and CABG, some patients need additional therapies for symptom relief and quality of life, especially those with diffuse CAD unsuitable for revascularization, multiple prior PCIs/CABG, lack of bypass conduits, severe LV systolic dysfunction after revascularization, or comorbidities making procedures high risk. Pharmacologic agents explored as adjuncts to standard therapy (nitrates, beta-blockers, calcium channel blockers, ranolazine) include high-dose statins, trimetazidine, perhexiline, nicorandil, allopurinol, ivabradine, fasudil, and testosterone. Experimental nonpharmacologic options include stem cell therapy, therapeutic angiogenesis, and mechanical therapies such as enhanced external counterpulsation, spinal cord stimulation, transmyocardial laser revascularization, and coronary sinus reducing devices.
In TACT, EDTA chelation infusions reduced a composite outcome (including mortality, recurrent MI, stroke, revascularization, or angina hospitalization), leading chelation therapy to be upgraded from Class III (not recommended) to Class IIb in 2014 stable ischemic heart disease guidelines. Allopurinol (xanthine oxidase inhibitor) at 600 mg daily for 6 weeks in a small crossover study of 65 heart failure patients increased median time to ST depression (232 to 393 seconds), but larger studies are needed before recommending it routinely. Testosterone may improve endothelial dysfunction and potentially angina, but safety concerns require more trials. EECP was assessed in MUST-EECP (139 outpatients randomized to 35 hours active EECP), showing it was well tolerated; exercise duration rose in both groups; active EECP increased time to 1-mm ST depression while inactive did not; and more active EECP patients had fewer angina episodes. Professional society updates state EECP may be considered for refractory angina. Treatments not shown to reduce cardiovascular risk or improve outcomes include estrogen therapy; vitamin C, vitamin E, beta-carotene supplementation; folate/B6/B12 therapy solely to lower homocysteine; chelation therapy (outside its limited guideline context); garlic; coenzyme Q10; selenium; and chromium.
Referral and Revascularization
Revascularization strategy is chosen to improve survival and/or symptoms and includes PCI (balloon angioplasty and stenting) or CABG. While PCI is clearly beneficial in acute MI, its role in stable CAD is less clear; PCI use for stable CAD fell substantially from 2007 to 2011, especially in high-volume PCI hospitals.
To improve survival, CABG is recommended for significant left main stenosis (>50%), proximal LAD stenosis >70%, three-vessel disease with >70% stenosis, or two-vessel disease with severe/extensive ischemia, and for patients with mild-to-moderate LV systolic dysfunction (EF 35%–50%) with significant multivessel CAD. A left internal mammary artery graft to the LAD improves survival. CABG is preferred over PCI to improve survival in multivessel CAD with SYNTAX score >22 and in multivessel CAD with diabetes, particularly when LIMA-to-LAD grafting is used. PCI may be a reasonable alternative to CABG in selected stable patients with unprotected left main CAD when SYNTAX is low-to-intermediate and/or surgical risk is high (e.g., STS operative mortality risk >5%), PCI procedural complication risk is low, and likelihood of good long-term outcome is high.
To improve symptoms, CABG or PCI can be beneficial for patients with one or more significant (>70%) stenoses amenable to revascularization who have unacceptable angina despite maximal medical therapy, or when medications cannot be intensified due to contraindications, adverse effects, or patient preference. The ORBITA trial (2017) showed no significant improvement in angina score after PCI in optimally treated stable angina, though most placebo-group patients later underwent PCI. The ISCHEMIA trial (2020) showed no benefit of routine invasive therapy over conservative treatment in moderate-to-severe ischemia, but excluded patients with acute coronary syndrome, severe/frequent symptoms, EF <35%, and left main stenosis. hybrid revascularization (lima-to-lad grafting plus pci to non-lad vessels) may be used when the aorta is unfavorable, cabg targets are poor, conduits unsuitable, or lad anatomy unfavorable for pci. compared with pci, provides more effective angina relief fewer repeat procedures but carries a higher procedural stroke risk; 10-year survival similar.< />pan>
PCI is widely used for symptom relief but is not superior to intensive medical therapy in preventing MI or death in stable patients. Candidates for PCI should also be candidates for CABG. About 80% experience immediate symptom benefit after PCI. Stents are used in the majority of PCI cases and reduce restenosis when used electively in atheromatous lesions. Key limitations of stenting include subacute thrombosis, in-stent restenosis, bleeding risk from antiplatelet therapy, and higher cost. Dual antiplatelet therapy (aspirin plus a P2Y12 inhibitor) prevents stent thrombosis; duration depends on stent type—about 4 weeks for bare metal stents and generally 6–12 months for drug-eluting stents due to delayed endothelialization. Newer drug-eluting stents with thin struts and limus-family drugs from durable polymers reduce stent thrombosis risk compared with early-generation sirolimus- or paclitaxel-eluting stents. Current evidence supports drug-eluting stents in most settings unless dual antiplatelet therapy is contraindicated.
Pearls and Considerations
Although nitrate responsiveness has traditionally been part of the diagnostic approach for stable ischemic heart disease, some evidence suggests that relief after nitroglycerin does not reliably predict active coronary artery disease in general chest pain admissions and should not be used alone to guide acute diagnosis. CABG offers higher long-term survival and fewer repeat revascularizations than PCI in some populations, but many patients prefer stenting because it is less invasive, involves shorter hospitalization, and has lower in-hospital mortality.
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