Predictable chest pain with exertion, relieved by rest or nitroglycerin. Atherosclerotic plaque causing fixed stenosis. Optimize with GDMT before revascularization. Lifestyle modification is foundation.
๐ Overview
Definition
Stable angina = predictable, reproducible chest discomfort triggered by exertion or emotional stress, lasting 2โ10 min, relieved by rest or sublingual nitroglycerin. Caused by fixed coronary stenosis limiting flow during increased demand.
Risk Stratification
Feature
Low Risk
High Risk
Stress test
No ischemia, good exercise capacity
Ischemia at low workload, โ EF with exercise, โฅ 2 mm ST depression
Based on ISCHEMIA, 2020 - no mortality benefit of routine revascularization over GDMT in stable CAD.
PCI - symptom relief only. No mortality benefit in stable CAD (COURAGE, 2007; ORBITA, 2018; REVIVED-BCIS2, 2022).
CABG - survival benefit in left main disease, 3-vessel disease with โ EF, or diabetes with multi-vessel disease (FREEDOM, 2012)
Bottom line: For stable CAD, GDMT is the foundation. Revascularization improves angina symptoms but does NOT reduce death or MI (ISCHEMIA, COURAGE, ORBITA). CABG has survival benefit only in left main, 3-vessel + reduced EF, or diabetes with multivessel disease (FREEDOM).
๐งช Workup
ECG - may be normal at rest. ST depression during pain.
Stress testing - exercise preferred. Pharmacologic if cannot exercise. Nuclear/echo for added anatomic info.
What did the ISCHEMIA trial show about revascularization in stable CAD?
No reduction in death or MI with routine invasive strategy vs conservative management in patients with stable CAD and moderate-severe ischemia. Invasive strategy improved anginal symptoms more. Key takeaway: GDMT is the foundation -revascularization is for symptom control in stable disease, not mortality reduction.
When does CABG provide a survival benefit over PCI?
Left main disease (โฅ 50% stenosis), 3-vessel disease with reduced EF, and diabetes with multi-vessel disease (FREEDOM trial). CABG provides more complete revascularization with better long-term outcomes in these high-risk anatomies.
Why is a nitrate-free interval important?
Continuous nitrate exposure โ nitrate tolerance within 24โ48h via depletion of sulfhydryl groups needed for NO generation. A 10โ14 hour nitrate-free interval (usually overnight) restores sensitivity. This is why isosorbide mononitrate is dosed once daily in the morning.
What is the mechanism of ranolazine?
Late sodium current inhibitor - reduces intracellular calcium overload without hemodynamic effects (no change in HR or BP). MERLIN-TIMI 36, 2007 showed reduced recurrent ischemia but no mortality benefit. Prolongs QTc - avoid with other QT-prolonging drugs.
What did the COURAGE trial show?
PCI + GDMT was not superior to GDMT alone for death or MI in stable CAD. Optimal medical therapy is the foundation of treatment. Revascularization improves symptoms but not hard outcomes. COURAGE, 2007.
Which patients benefit from CABG over PCI in diabetes?
FREEDOM, 2012: CABG superior to PCI for death, MI, and stroke in diabetics with multivessel disease. Lower rates of repeat revascularization with CABG. Drives current guideline recommendation for surgical revascularization in this population.
What is the Canadian Cardiovascular Society (CCS) angina classification?
Class I: ordinary activity doesn't cause angina (e.g., walking, climbing stairs). Class II: slight limitation - angina with rapid walking or climbing > 1 flight. Class III: marked limitation - angina walking 1-2 blocks or 1 flight. Class IV: angina at rest or with any physical activity.
When should you choose pharmacologic vs exercise stress testing?
Pharmacologic if patient cannot exercise (orthopedic limitation, deconditioning, PAD) or has uninterpretable ECG (LBBB, paced rhythm, LVH with repolarization changes, digoxin use). Exercise preferred when possible - provides functional capacity data and is more physiologic.
What is the role of coronary calcium scoring?
CAC = 0 has excellent negative predictive value for obstructive CAD. MESA study validated its use for risk reclassification. Helps reclassify intermediate-risk patients (moves them to low or high risk). Not useful if patient already has known CAD. Obtained via non-contrast CT chest.
Clinical Examples
๐ Case 1, New Diagnosis of Stable Angina
Patient: 64M with HTN, HLD, T2DM. Exertional chest pressure with brisk walking ร 3 months, relieved by rest within 5 min. Normal ECG at rest. EF 60%.
Key findings: Classic stable angina: predictable exertional chest pain, relieved by rest. Intermediate pretest probability for CAD given age, sex, and risk factors.
Management:
Stress test for risk stratification, exercise stress echo (can exercise, interpretable ECG)
If high-risk stress test (large ischemic burden, drop in BP) โ coronary angiography
Teaching point: Beta-blockers are first-line for stable angina, they reduce mortality in post-MI patients and improve anginal symptoms. CCBs (amlodipine, diltiazem) are second-line or added if beta-blockers insufficient.
๐ Case 2, Refractory Angina Despite Medical Therapy
Patient: 72F with known 3-vessel CAD (declined CABG 2 years ago). Angina now occurring with minimal exertion despite metoprolol 100 mg BID, amlodipine 10 mg, isosorbide mononitrate 60 mg daily, ASA, atorvastatin. CCS class III.
Key findings: Refractory angina on maximized triple anti-anginal therapy. Previously documented 3-vessel disease. Progressive limitation despite optimal medical management.
Management:
Add ranolazine 500 mg BID โ titrate to 1000 mg BID (late sodium channel inhibitor, reduces ischemia without hemodynamic effects)
Heart team discussion: CABG vs high-risk PCI for 3-vessel disease ISCHEMIA, 2020
Cardiac rehab referral (improves exercise capacity and anginal threshold)
Ensure nitrate-free interval (10-14h overnight) to prevent tolerance
Teaching point: Ranolazine is the fourth-line anti-anginal agent, it works by a unique mechanism (late Na channel) and can be added to any combination without hemodynamic interactions. No mortality benefit, but improves symptoms.
๐ Case 3, Vasospastic (Prinzmetal) Angina
Patient: 42F non-smoker, no traditional risk factors. Recurrent rest angina at 3-4 AM with transient ST elevation on telemetry that resolves spontaneously. Normal coronary angiogram.
Key findings: Classic vasospastic angina: rest pain, early morning, transient ST elevation, clean coronaries. Often triggered by smoking, cocaine, or cold exposure.
Management:
Long-acting CCB first-line: amlodipine 5-10 mg daily or diltiazem ER 240 mg daily
Teaching point: Beta-blockers are contraindicated in vasospastic angina, they remove beta-2 vasodilation, leaving alpha-mediated constriction unopposed. This is the one form of angina where beta-blockers make things worse.