Review Question - QID 100609

Angiotensin-convertting enzyme (ACE) inhibitors such as lisinopril are considered first-line treatment for hypertension in patients with a history of myocardial infarction (MI).

ACE inhibitors work to not only lower blood pressure, but they also inhibit myocardial remodeling that can result in a decrease in contractile function. Thus, for patients with chronic ischemic cardiac failure, ACE inhibitors are considered first-line treatment since they are cardio-protective in nature. For patients with uncomplicated hypertension, thiazide diuretics are first-line treatment. ACE inhibitors function by stopping the conversion of angiotensin I to angiotensin II, thereby lowering blood pressure. A beta-blocker would also be a first-line agent in patients with history of MI.

Guirguis-Blake discusses the use of adding ACE inhibitors and angiotensin-receptor blockers (ARBs) to the therapy for patients with ischemic heart disease. By adding an ACE inhibitor to standard therapy, there has been a proven reduction in total mortality and cardiovascular events in this patient population. Additionally, combination treatment with an ACE inhibitor and an ARB in patients with ischemic heart disease, but without heart failure, was found to cause more harm with no added effectiveness and should therefore not be encouraged.

Kirkpatrick et al. report on ventricular remodeling in heart failure patients. They note that ventricular remodeling is progressive and has the potential to portend a poor prognosis due to the structural and functional changes that take place. The Survival And Ventricular Enlargement (SAVE) trial found that ACE inhibitors undoubtedly reduced total and cardiovascular mortality, recurrent myocardial infarction, and the incidence of heart failure in post-MI patients.

Illustrations A is a flow chart of the renin angiotensin system and where ACE inhibitors work in that system. Illustration B depicts a generalized schematic of changes that occur after an MI.

Incorrect Answers:
Answer 1: Amlodipine is a calcium channel blocker that is considered a first or second-line treatment for hypertension, but not first-line in patients with history of MI.
Answer 2: Hydrochlorothiazide is a first-line choice for uncomplicated hypertension.
Answer 4: Prazosin has antihypertensive characteristics (alpha 1 blocking) that make it a second-line choice for the treatment of hypertension.
Answer 5: Isoproterenol is a beta agonist that treats bradycardia and heart block, but not hypertension.