The correct answer is D. There is clear and convincing evidence that beta-blockers are indicated in the treatment of patients who have coronary artery disease. Beta blockers provide mortality benefit for patients with known coronary artery disease and heart failure. This is partly because in addition to lowering blood pressure, beta-blockers keep the heart rate slow, which decreases strain on the heart by decreasing myocardial oxygen demand and increases myocardial perfusion. Because this patient has coronary artery disease and hypertension, the best choice for this patient is metoprolol.
Diltiazem (choice A) is a calcium-channel blocker that also has blood pressure lowering properties together with heart rate controlling properties. This class of medications has not been shown clearly to decrease mortality in patients who have coronary artery disease, so they are not used as first-line agents. They can be considered in patients who require heart rate control but who cannot tolerate beta-blockers (e.g., asthmatics, peripheral arterial disease).
Hydrochlorothiazide (choice B) together with beta-blockers can be used as a first-line blood pressure medication in many patients. It helps to potentiate other antihypertensive agents so if it is not the first-line agent chosen, it probably is a good second-line add on medication. Hydrochlorothiazide has synergistic blood pressure lowering effects with many other classes of blood pressure medications. Because of our patient's proven coronary artery disease, a beta-blocker would be a better choice for this patient.
Lisinopril (choice C) is in the class of antihypertensives known as ACE inhibitors. ACE inhibitors are indicated as first-line blood pressure medications in patients who have diabetes, because they have been shown to slow the progression of diabetic nephropathy. They also have been shown to improve survival and are first-line agents in patients who have known congestive heart failure because they act as an after-load reducer. Finally, in postmyocardial infarction patients who have left ventricular damage, ACE inhibitors seem to have a beneficial effect on survival secondary to a lessening of the remodeling effect on the ventricle. ACE inhibitors act as vasodilators in patients who have chronic heart failure, and they are most effective in patients who have the lowest ejection fraction from their left ventricle.
Nifedipine (choice E) is a dihydropyridine calcium-channel blocker that acts to inhibit calcium ion influx into vascular smooth muscle and myocardium. It acts as a predominantly peripherally acting antihypertensive. It acts as a peripheral vasodilator and decreases blood pressure. It is known to have the side effect of reflex tachycardia, so it is not first-line therapy for postmyocardial infarction or angina patients.
PEARL: Beta-blockers have been shown to decrease mortality in patients who have coronary artery disease and in post-myocardial infarction patients. Its effect is to decrease the heart rate and allow increased perfusion of the cardiac tissue. It also decreases the incidence of arrhythmias. There is mortality benefit demonstrated with the use of beta-blockers.
