Test your medicine knowledge with the MKSAP challenge, in partnership with the American College of Physicians.

A 66-year-old man is evaluated in the hospital following ST-elevation myocardial infarction treated with primary percutaneous coronary intervention of the left anterior descending artery 4 days ago. His initial presentation was complicated by the presence of heart failure and pulmonary edema. He is asymptomatic and ambulating, and he is nearly ready for discharge. Medical history is significant for hyperlipidemia, type 2 diabetes mellitus, and hypertension. Medications are aspirin, prasugrel, lisinopril, carvedilol, atorvastatin, and basal and prandial insulin.

On physical examination, vital signs are normal. Oxygen saturation is 99% breathing ambient air. The remainder of the examination is unremarkable.

Laboratory studies are significant for a serum creatinine level of 1.0 mg/dL (88.4 µmol/L) and a serum potassium level of 3.7 mEq/L (3.7 mmol/L).

An echocardiogram shows a left ventricular ejection fraction of 35%.

Which of the following is the most appropriate treatment?

A. Eplerenone
B. Isosorbide mononitrate
C. Valsartan
D. Warfarin

MKSAP Answer and Critique

The correct answer is A. Eplerenone.

The most appropriate treatment is eplerenone. This patient had an anterior ST-elevation myocardial infarction (STEMI) complicated by moderate left ventricular (LV) dysfunction and heart failure. Optimizing this patient’s medical therapy is fundamental to preventing further impairment of LV function and promoting favorable LV remodeling. Although beta-blockers and angiotensin-converting enzyme (ACE) inhibitors (or angiotensin receptor blockers [ARBs]) form the backbone of postinfarction medical therapy aimed at preserving LV function, it is important to recognize when additional agents may be indicated. The EPHESUS trial established the benefits of aldosterone antagonism with eplerenone in patients with acute myocardial infarction and concomitant LV dysfunction, and current guidelines recommend adding an aldosterone antagonist to ACE inhibitor and beta-blocker therapy in STEMI patients with LV ejection fraction of 40% or less and either heart failure symptoms or diabetes mellitus. Because of the potassium-sparing effect of eplerenone, serum potassium levels should be carefully monitored. Eplerenone should be used with caution in those with underlying kidney disease.

Long-acting nitrates, such as isosorbide mononitrate, have no role in the management of patients immediately after STEMI. Nitrates may be used for future angina or may be coupled with hydralazine in those with persistent LV dysfunction despite maximally tolerated doses of a beta-blocker and ACE inhibitor; however, administering isosorbide mononitrate is not the most appropriate next step in this patient’s management.

Although an ARB such as valsartan may be useful as an alternative to ACE inhibitor therapy, adding an ARB to a medication regimen that already includes an ACE inhibitor and beta-blocker has been associated with an excess of adverse events and is therefore not recommended.

Warfarin therapy is recommended to reduce the risk for systemic embolization in patients with LV apical clots following large anterior myocardial infarction, although this recommendation is not based on a large randomized dataset. In this patient, no clots were noted on the echocardiogram, and empiric anticoagulation is not indicated according to current guidelines.

Key Point

• In patients with STEMI, LV ejection fraction of 40% or less, and either heart failure symptoms or diabetes mellitus, an aldosterone antagonist is recommended in addition to ACE inhibitor and beta-blocker therapy.

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