A 48-year-old woman with hypertension and a history of acute coronary syndrome (ACS) 6 months ago presents for antihypertensive optimization. She is already on aspirin and a statin. Which antihypertensive agent is the preferred first-line choice for secondary prevention of recurrent cardiovascular events?

Explanation

## First-Line Antihypertensive Post-ACS: Beta-Blockers **Key Point:** Beta-blockers are the preferred first-line antihypertensive agents in patients with a history of acute coronary syndrome (ACS) because they reduce mortality, reinfarction risk, and arrhythmias. ### Mechanism of Cardioprotection Post-ACS 1. **Reduced myocardial oxygen demand:** β1-blockade decreases heart rate, contractility, and blood pressure. 2. **Anti-arrhythmic effect:** Reduce ventricular ectopy and sudden cardiac death risk. 3. **Plaque stabilization:** Reduce shear stress on atherosclerotic plaques. 4. **Mortality reduction:** Proven in multiple landmark trials (CIBIS, COPERNICUS, MERIT-HF). ### Comparison of Options in Post-ACS Setting | Agent | Class | Post-ACS Benefit | Mechanism | First-Line? | | --- | --- | --- | --- | --- | | **Carvedilol** | Beta-blocker (with α-blocking) | ✓✓ (proven mortality ↓) | Reduces HR, contractility, afterload | **Yes** | | Diltiazem | Non-dihydropyridine CCB | ✓ (limited, if BB contraindicated) | Rate control, mild negative inotrope | No (2nd-line) | | Nifedipine | Dihydropyridine CCB | ✗ (may increase reflex tachycardia) | Vasodilation, reflex sympathetic activation | No | | Chlorthalidone | Thiazide-like diuretic | ✗ (no mortality benefit post-ACS) | Natriuresis, volume depletion | No | **High-Yield:** Carvedilol (or metoprolol, bisoprolol) is guideline-recommended as first-line post-ACS. Carvedilol has additional alpha-blocking properties, reducing afterload and improving hemodynamics in heart failure (if present). **Clinical Pearl:** Beta-blockers should be initiated early (within 24 hours of ACS if hemodynamically stable) and continued long-term. Target heart rate is typically 50–60 bpm at rest. Avoid abrupt withdrawal (risk of rebound hypertension and ischemia). **Mnemonic:** **ABCDE** of post-ACS therapy: - **A**spirin - **B**eta-blocker - **C**holesterol-lowering (statin) - **D**iuretic (if HF) - **E**ACE inhibitor (if LV dysfunction) ### Why Carvedilol is Superior - Proven reduction in cardiovascular mortality post-ACS - Reduces reinfarction and arrhythmia risk - Combined alpha/beta blockade improves hemodynamics - Guideline-recommended by ACC/AHA and ESC [cite:Harrison 21e Ch 297]