Medication Summary
Angiotensin-converting enzyme inhibitors (ACEIs) and diuretics are the mainstay of medical therapy for patients with mitral regurgitation (MR) (mitral valve insufficiency).
Afterload reducers
Class Summary
These agents are used to improve preoperative or postoperative cardiac output. They reduce systemic vascular resistance and increase systemic blood flow resulting from myocardial dysfunction, significant mitral valve insufficiency, or both.
Captopril (Capoten)
Prevents conversion of angiotensin I to angiotensin II, a potent vasoconstrictor, resulting in lower aldosterone secretion.
By decreasing the systemic blood pressure, ACE inhibitors decrease the amount of work placed on the heart. The regurgitant fraction also is decreased because of the lower systemic blood pressure.
Enalapril (Enalaprilat, Epaned, Vasotec)
Enalapril is a prodrug hydrolyzed in vivo to enalaprilat. Enalaprilat prevents conversion of angiotensin I to angiotensin II (a potent vasoconstrictor) through competitive inhibition of angiotensin-converting enzyme (ACE), resulting in decreased plasma angiotensin II concentrations. Blood pressure may be reduced in part through decreased vasoconstriction, increased renin activity, and decreased aldosterone secretion.
Hydralazine (Apresoline)
Decreases systemic resistance through direct vasodilation of arterioles.
Nifedipine (Procardia, Adalat)
Relaxes coronary smooth muscle and produces coronary vasodilation, which in turn improves myocardial oxygen delivery.
Nitroprusside (Nitropress)
Afterload-reducing agent used for acute MR. Produces vasodilation and increases inotropic activity of the heart. At higher doses, may exacerbate myocardial ischemia by increasing the heart rate.
Diuretic agents
Class Summary
These agents promote excretion of water and electrolytes by the kidneys. They are used to treat heart failure or hepatic, renal, or pulmonary disease when sodium and water retention have resulted in edema or ascites.
Furosemide (Lasix)
Increases excretion of water by interfering with chloride-binding cotransport system, which in turn, inhibits sodium and chloride reabsorption in ascending loop of Henle and distal renal tubule. Dose must be individualized. Depending on response, administer at increments of 20-40 mg, no sooner than 6-8 h after the previous dose, until desired diuresis occurs. When treating infants, titrate using increments of 1 mg/kg/dose until a satisfactory effect is achieved.
Spironolactone (Aldactone)
For management of edema resulting from excessive aldosterone excretion. Competes with aldosterone for receptor sites in distal renal tubules, increasing water excretion while retaining potassium and hydrogen ions.
Ethacrynic acid (Edecrin)
Use as a second-line IV diuretic for those with congestive heart failure. Inhibits loop of Henle and proximal and distal convoluted tubule sodium and chloride resorption.
Inotropic Agents
Class Summary
These are effective medications when cardiac function is slightly decreased or compromised by the amount of mitral regurgitation. Positive inotropic agents increase the force of contraction of the myocardium and are used to treat acute and chronic congestive heart failure. Some agents may also increase or decrease the heart rate (ie, positive or negative chronotropic agents), provide vasodilatation, or improve myocardial relaxation. These additional properties influence the choice of drug for specific circumstances. Cardiac glycosides are used predominantly for their inotropic effects.
Digoxin (Lanoxin)
Cardiac glycoside with direct inotropic effects in addition to indirect effects on the cardiovascular system. Acts directly on cardiac muscle, increasing myocardial systolic contractions. Its indirect actions result in increased carotid sinus nerve activity and enhanced sympathetic withdrawal for any given increase in mean arterial pressure.
Milrinone
Bipyridine-positive inotropic agent and vasodilator with little chronotropic activity. Different in mode of action from both digitalis glycosides and catecholamines.
Anticoagulants
Class Summary
These agents prevent recurrent or ongoing thromboembolic occlusion of the vertebrobasilar circulation. Lifelong anticoagulation therapy is needed in patients with mechanical valves.
Warfarin (Coumadin)
Interferes with hepatic synthesis of vitamin K–dependent coagulation factors. Used for prophylaxis and treatment of venous thrombosis, pulmonary embolism, and thromboembolic disorders. Tailor dose to maintain an INR in the range of 2-3.
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Acute stage of mitral regurgitation (MR) (mitral valve insufficiency).
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Chronic compensated stage of mitral regurgitation (MR) (mitral valve insufficiency).
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Chronic decompensated stage of mitral regurgitation (MR) (mitral valve insufficiency).
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Dilated cardiomyopathy with significant mitral regurgitation (MR) (mitral valve insufficiency) by transthoracic echocardiogram (A) and cardiac magnetic resonance imaging (B).
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Cleft mitral valve seen in parasternal short axis view (A) with mild mitral regurgitation (MR) (mitral valve insufficiency) in 4-chamber apical view (B).
