What is the gold standard treatment for different types of angina?

Types of Angina and Gold Standard Treatment

Major Types of Angina

Angina is classified into three main types based on underlying pathophysiology: chronic stable angina (caused by obstructive epicardial coronary disease), microvascular angina (caused by coronary microvascular dysfunction), and vasospastic angina (Prinzmetal's angina caused by coronary artery spasm). 1, 2

Chronic Stable Angina

• Results from fixed obstructive atherosclerotic lesions in epicardial coronary arteries that limit oxygen delivery during increased myocardial demand 1
• Characterized by predictable chest pain with exertion that is relieved by rest 3

Microvascular Angina

• Occurs in up to 40% of patients with angina symptoms, particularly women 1, 4
• Previously known as cardiac syndrome X, characterized by normal or near-normal coronary arteries on angiography with evidence of ischemia on stress testing 1
• Explains why myocardial ischemia can persist even after successful complete coronary revascularization 1

Vasospastic Angina (Prinzmetal's Angina)

• Caused by coronary artery vasospasm, often occurring at rest 2
• Requires specific treatment approach distinct from other angina types 2

Gold Standard Treatment Approach

Dual Treatment Goals Framework

Treatment of angina has two fundamentally separate goals that cannot be achieved with the same medications: preventing MI and death (prognostic therapy) versus reducing symptoms and improving quality of life (symptomatic therapy). 1, 4

Prognostic Therapy (Preventing Death and MI)

• Aspirin 75-325 mg daily should be used routinely in all patients with chronic ischemic heart disease 1, 4
• Statins for cardiovascular event prevention 1, 4
• ACE inhibitors for patients with coexisting hypertension, heart failure, LV dysfunction, prior MI, or diabetes 4
• These medications do NOT alleviate angina symptoms 1, 4

Symptomatic Therapy (Reducing Angina)

No antianginal drug has been proven to reduce cardiovascular mortality or myocardial infarction rates 1, 4

First-Line Symptomatic Treatment by Angina Type

For Chronic Stable Angina and Microvascular Angina

β-blockers should be strongly considered as initial symptomatic therapy for chronic stable angina, with target doses of bisoprolol 10 mg once daily, metoprolol 200 mg once daily, or atenolol 100 mg daily. 1, 4

• β-blockers reduce cardiac events when used as secondary prevention in post-infarction patients and reduce mortality in hypertensive patients 1
• Diabetes mellitus is NOT a contraindication to β-blocker use 1

Calcium channel blockers are equally effective as first-line therapy and can be used as alternatives or in combination with β-blockers. 1, 4

Short-acting nitrates (sublingual nitroglycerin) are essential for immediate symptom relief and situational prophylaxis before known triggers. 4

• Patients should sit during first use to prevent hypotension 4
• Long-acting nitrates can be combined synergistically with β-blockers to block reflex tachycardia 1, 4
• Critical caveat: Nitrates have disappointing results in microvascular angina because small arterioles are nitrate-resistant 1

For Vasospastic Angina (Prinzmetal's)

Calcium channel blockers are the gold standard first-line therapy for Prinzmetal's angina, with the following dosing regimens: Verapamil 240-480 mg per day, Diltiazem 180-360 mg per day, or Nifedipine 60-120 mg per day. 2

• Calcium channel blockers directly block coronary artery vasospasm through inhibition of calcium influx into vascular smooth muscle 2
• Long-acting nitrates are also first-line and can be used when calcium channel blockers are not tolerated 2

CRITICAL CONTRAINDICATION: β-blockers are absolutely contraindicated in vasospastic angina because they cause unopposed alpha-mediated vasoconstriction, worsening coronary spasm. 2

• Smoking cessation is mandatory as smoking triggers coronary vasospasm 2

Second-Line Agents

When first-line therapy is inadequate, second-choice medications include ivabradine, nicorandil, ranolazine, and trimetazidine—though no direct comparisons have demonstrated superiority of first-choice over second-choice agents. 1, 4

• Meta-analyses show all antianginal drugs have similar efficacy in reducing symptoms 1
• Newer second-choice drugs actually have more contemporary evidence-based clinical data than traditional first-choice drugs 1

Combination Therapy Strategy

Double or triple therapy with additive or synergistic effects is often needed to control symptoms effectively. 1, 4

• Nitrates combined with β-blockers provide synergistic anti-ischemic effects by blocking reflex tachycardia that nitrates induce 1, 4
• Combinations should be tailored to the specific type of angina and patient comorbidities 1

Revascularization Indications

Percutaneous Coronary Intervention (PCI) is effective for patients with angina not satisfactorily controlled by medical treatment when anatomically suitable lesions are present. 4

Coronary Artery Bypass Grafting (CABG) is indicated for significant artery stenosis (50% left main narrowing or proximal three-vessel disease) and may reduce mortality in specific subgroups: left main stem stenosis, proximal LAD stenosis, or three-vessel disease with impaired LV function. 1, 4

Common Pitfalls to Avoid

• Do not use dipyridamole as an antiplatelet agent in stable angina—it can enhance exercise-induced myocardial ischemia 1
• Do not assume revascularization eliminates need for medical therapy—many patients have persistent angina after successful revascularization due to microvascular dysfunction 1
• Do not use β-blockers in vasospastic angina—this is an absolute contraindication 2
• Do not expect symptomatic antianginal drugs to improve survival—they improve quality of life but not mortality 1, 4