EVIDENCE-BASED ANSWER
PATIENTS SHOULD BE PLACED ON THE FOLLOWING MEDICATIONS :
- antiplatelet agents (strength of recommendation [SOR]: A, meta-analysis for aspirin; A, multiple randomized controlled trials [RCTs] for aspirin plus clopidogrel)
- a statin; atorvastatin has the best evidence (SOR: B, a single RCT)
- a beta-blocker (SOR: A, meta-analysis)
- renin-angiotensin-aldosterone system blockers, whether or not the ejection fraction is diminished after myocardial infarction (MI) (SOR: A, meta-analysis for angiotensin-converting enzyme [ACE] inhibitor; B, single RCT for ACE inhibitor plus aldosterone blocker). ( TABLE )
Evidence summary
A systematic review of 9 RCTs demonstrated that aspirin (75-325 mg) started soon after the onset of acute MI significantly reduced mortality, reinfarction, and stroke at 1 month compared with placebo (absolute risk reduction [ARR]=3.8%; number needed to treat [NNT]=26; 95% confidence interval [CI], 23-30).1
One large RCT involving 17,187 patients with suspected acute MI showed that 162 mg aspirin given on the day of the MI resulted in a 2.6% ARR (NNT=38; 95% CI, 29-63) in vascular deaths at 35 days compared with placebo.2 The survival benefit persisted for as long as 10 years. The RCT also found no significant difference between aspirin and placebo in rates of cerebral hemorrhage or bleeding requiring transfusions.
Patients who have had an MI without ST segment elevation should take clopidogrel (75 mg/d) and aspirin (81 mg/d) for 12 months. The combination has been shown to result in a 2.1% ARR (NNT=48) in deaths, recurrent MI, and stroke compared with aspirin alone.3 Patients who have had an ST segment elevation MI should take clopidogrel in combination with aspirin for at least 2 weeks.4
TABLE
Recommended drugs for post-MI patients
| Drug type | Examples | Precautions | Contraindications |
|---|---|---|---|
| Antiplatelet agents | Aspirin 81 mg/d; clopidogrel 75 mg/d | Risk for bleeding; use caution in patients taking warfarin | Active bleeding; hypersensitivity |
| RAAS blockers | Lisinopril 20 mg/d; losartan 50 mg/d; eplerenone 50 mg/d | Hypotension, hyperkalemia, renal failure Use eplerenone only with decreased ejection fraction | Hypersensitivity; systolic blood pressure <90 mm Hg |
| Beta-blockers | Metoprolol 100 mg bid | Hypotension, bradycardia, reactive airways | Systolic blood pressure <90 mm Hg; pulse rate <50 bpm |
| Statins | Atorvastatin 80 mg/d | Elevated AST/ALT, myositis | Active liver disease; pregnancy/nursing |
| ALT, alanine aminotransferase; AST, aspartate aminotransferase; BPM, beats per minute; RAAS, renin-angiotensin-aldosterone system. | |||
Intensive atorvastatin therapy lowers risk of death
The PROVE IT-TIMI 22 trial showed the benefit of early intensive therapy with the hydroxymethyl glutaryl coenzyme A reductase inhibitor atorvastatin to lower low-density lipoprotein <70 mg/dL post-MI.5 At 30 days after the event, atorvastatin 80 mg daily resulted in a 1.2% ARR in death and recurrent acute coronary syndrome (NNT=83; hazard ratio [HR]=0.72; 95% CI, 0.52-0.99). From 6 months to 24 months after the event, the ARR was 2.6% (NNT=38; HR=0.82; 95% CI, 0.69-0.99).
Beta-blockers significantly decrease late mortality
One systematic review of 63 RCTs showed that, in long-term trials, use of a beta-blocker significantly reduced the late mortality rate (NNT=48; odds ratio [OR]=0.77; 95% CI, 0.70-0.85).6 In another review of 82 RCTs, the mortality rate between 6 months and 4 years after MI decreased markedly in patients receiving a beta-blocker (OR=0.77; 95% CI, 0.69-0.85).7
ACE inhibitors decrease overall mortality, sudden cardiac death
An ACE inhibitor should be started regardless of the ejection fraction or the presence or absence of left ventricular systolic dysfunction. One systematic review that compared long-term mortality rates of patients started on an ACE inhibitor within 14 days of acute MI versus placebo found that ACE inhibitors significantly decreased overall mortality and sudden cardiac deaths between 2 and 42 months after the MI (NNT=42; OR=0.83; 95% CI, 0.71-0.97).8