How should hypertension be managed in a patient who has had a myocardial infarction?

Management of Hypertension Post-Myocardial Infarction

Beta-blockers and ACE inhibitors (or ARBs if intolerant) form the cornerstone of hypertension management after MI, with a target blood pressure of <130/80 mmHg in most patients, while carefully avoiding diastolic pressures below 60 mmHg to preserve coronary perfusion. 1, 2

Immediate Post-MI Management (First 24 Hours)

• Initiate oral beta-blockers within 24 hours in all hemodynamically stable patients without contraindications (Class I, Level A). 1, 3
• Preferred beta-blockers include carvedilol, metoprolol succinate, or bisoprolol, which have proven mortality benefits (23% reduction in all-cause mortality). 1, 2
• Do not start beta-blockers if the patient has acute heart failure, cardiogenic shock, heart block (second or third-degree AV block), severe bradycardia, hemodynamic instability, or severe COPD. 1
• Add ACE inhibitor early (within 24 hours), particularly for anterior MI, persistent hypertension, left ventricular dysfunction (LVEF <40%), heart failure, or diabetes. 4, 5
• For ACE inhibitors, start lisinopril 5 mg orally, followed by 5 mg after 24 hours, 10 mg after 48 hours, then 10 mg daily for at least 6 weeks. 5
• If systolic BP is ≤120 mmHg but >100 mmHg during the first 3 days, initiate ACE inhibitor at 2.5 mg. 5

Blood Pressure Targets

• Target BP <130/80 mmHg for most post-MI patients, which reduces cardiovascular events by 25% and all-cause mortality by 27%. 1, 2, 4
• **Target BP <140/90 mmHg** is acceptable in elderly patients (>80 years). 1
• For patients with diabetes or chronic kidney disease, maintain target <130/80 mmHg. 3
• Critical caveat: Avoid lowering diastolic BP below 60 mmHg, especially in patients with diabetes or age ≥60 years, as this compromises coronary perfusion and increases risk of recurrent ischemic events. 3, 2, 4

Medication Algorithm

First-Line Therapy (All Post-MI Patients)

1. Beta-blocker + ACE inhibitor (or ARB if ACE inhibitor intolerant). 1, 2, 4
2. ACE inhibitors reduce cardiovascular mortality by 20-22% in post-MI patients. 2
3. For ACE inhibitor intolerance, use ARBs (particularly valsartan), which have comparable efficacy (Class I, Level A). 2
4. Never combine ACE inhibitor with ARB, as this increases adverse events without survival benefit. 2, 4

Second-Line Therapy (If BP Goal Not Met)

• Add thiazide diuretic (e.g., hydrochlorothiazide 12.5 mg) if BP remains ≥130/80 mmHg on beta-blocker and ACE inhibitor. 3, 1, 2, 4
• Thiazide diuretics are effective for achieving BP control and are appropriate for long-term management (Level A). 2
• Avoid combining thiazide diuretics with beta-blockers in patients with metabolic syndrome or high diabetes risk; consider vasodilating beta-blockers (carvedilol, nebivolol) instead. 2

Third-Line Therapy (For Persistent Angina or Uncontrolled BP)

• Add long-acting dihydropyridine calcium channel blocker (e.g., amlodipine) if angina persists despite beta-blocker therapy and BP remains uncontrolled (Class I). 1, 4
• Dihydropyridine CCBs are effective antianginal agents that lower BP when added to beta-blockers. 1
• Never use short-acting dihydropyridine CCBs (e.g., immediate-release nifedipine) post-MI due to increased mortality risk (Class III, Level B). 3, 4
• Non-dihydropyridine CCBs (verapamil, diltiazem) are not preferred for secondary cardiac protection as they do not prevent ventricular dilatation or heart failure. 3

Special Populations

Patients with LVEF ≤40% and Heart Failure or Diabetes:

• Add aldosterone antagonist (eplerenone or spironolactone), which reduces total mortality by 15% at 16 months (Class I, Level A). 3, 1, 2
• Ensure creatinine <2.5 mg/dL (men) or <2.0 mg/dL (women) and potassium <5.0 mEq/L before initiating. 3
• Monitor serum potassium routinely, especially when combining with ACE inhibitors or ARBs. 3, 4

Patients with Renal Impairment:

• For creatinine clearance 10-30 mL/min, reduce initial ACE inhibitor dose by 50% (e.g., lisinopril 5 mg for hypertension, 2.5 mg for heart failure or acute MI). 5
• For hemodialysis or creatinine clearance <10 mL/min, start lisinopril at 2.5 mg once daily. 5

Long-Term Management

• Continue beta-blocker indefinitely unless contraindications develop, with proven benefit extending beyond 3 years post-MI. 1, 2
• Continue ACE inhibitor (or ARB) indefinitely, particularly if LVEF <40%, hypertension, diabetes, or chronic kidney disease. 1, 2
• Most patients require 2 or more antihypertensive medications to achieve target BP. 3, 4
• When BP is >20/10 mmHg above goal, initiate 2 drugs simultaneously. 3

Lifestyle Modifications

• Sodium restriction to <2 g/day, DASH or Mediterranean diet pattern, weight reduction to BMI 18.5-24.9 kg/m², aerobic exercise 30-60 minutes daily, alcohol moderation, and smoking cessation for all patients with BP ≥120/80 mmHg. 4

Monitoring Strategy

• Home BP monitoring improves control and patient engagement. 4
• Monitor serum creatinine/eGFR and potassium when using ACE inhibitors, ARBs, or diuretics. 4
• Assess for symptoms of worsening ischemia, especially if diastolic BP <60 mmHg. 4

Critical Pitfalls to Avoid

• Do not lower BP too aggressively in acute MI, as excessive reduction compromises coronary perfusion in diseased vessels. 4
• Avoid short-acting dihydropyridine CCBs in post-MI patients due to increased mortality. 3, 4
• Do not initiate beta-blockers in hemodynamically unstable patients. 4
• Uncontrolled hypertension is a contraindication to fibrinolytic therapy due to intracranial hemorrhage risk. 4
• Avoid excessive diastolic BP lowering (<60 mmHg), particularly in older patients and those with diabetes, as this increases coronary event risk. 3, 2