Aortic insufficiency medical management

Associate Editor-In-Chief: ; Varun Kumar, M.B.B.S.; Lakshmi Gopalakrishnan, M.B.B.S.

Medical therapy of chronic aortic insufficiency involves the use of vasodilators. Small trials have demonstrated a benefit from the administration of ACE inhibitors, nifedipine, sodium nitroprusside and hydralazine in improving left ventricular wall stress, ejection fraction, and left ventricular mass. The use of these vasodilators is indicated only in those individuals who suffer from hypertension in addition to aortic insufficiency. The goal in using these pharmacologic agents is to decrease the afterload so that the left ventricle is unloaded. This results in reduction in left ventricular end diastolic pressure thereby preserving the left ventricular systolic function and also benefits the patients in left ventricular failure secondary to aortic insufficiency.

Long term therapy with nifedipine and hydralazine have shown to increase left ventricular ejection fraction, reduce left ventricular end diastolic volume and reduction in left ventricular mass thereby delaying the need for valve surgery. While ACE inhibitors such as enalapril and quinapril have shown to decrease left ventricular mass and end diastolic volume but with no influence on ejection fraction

Patients with severe aortic insufficiency with normal left ventricular function are recommended to undergo surgery though there are no sufficient evidences against medical management.

Use of drugs other than vasodilators, such as digoxin, diuretics and other positive inotropic drugs for long term treatment have no supporting data. Beta blockers are relatively contraindicated since they decrease heart rate and prolong diastolic phase. There by increasing the back flow of blood from aorta. However beta blockers can be considered in patients with bicuspid aortic valve with mild aortic insufficiency and aortic root diameter of more than 40mm.

ACC/AHA guidelines for use of Vasodilator therapy in Chronic severe Aortic Insufficiency
Class I Vasodilator therapy is indicated for chronic therapy in patients with severe aortic insufficiency who have symptoms or left ventricular dysfunction when surgery is not recommended because of additional cardiac or noncardiac factors.

Class IIa Vasodilator therapy is reasonable for short-term therapy to improve the hemodynamic proﬁle of patients with severe heart failure symptoms and severe left ventricular dysfunction before proceeding with aortic valve replacement.

Class IIb Vasodilator therapy may be considered for long-term therapy in asymptomatic patients with severe aortic insufficiency who have left ventricular dilatation but normal systolic function.

Class III
 * 1) Vasodilator therapy is not indicated for long-term therapy in asymptomatic patients with mild to moderate aortic insufficiency and normal left ventricular systolic function.
 * 2) Vasodilator therapy is not indicated for long-term therapy in asymptomatic patients with left ventricular systolic dysfunction who are otherwise candidates for aortic valve replacement.
 * 3) Vasodilator therapy is not indicated for long-term therapy in symptomatic patients with either normal left ventricular function or mild to moderate left ventricular systolic dysfunction who are otherwise candidates for aortic valve replacement.

Prophylactic antibiotics prior dental procedures are not recommended for all patients with aortic insufficiency as per 2007 AHA guidelines (for infective endocarditis) unless there are other indications.

Aortic insufficiency in pregnancy
Isolated aortic insufficiency in pregnant patients can be managed with combination of diuretics and vasodilators. ACE inhibitors are contraindicated in pregnancy. Patients with signs and symptoms of left ventricular failure should be monitored throughout labor and delivery with strict attention to volume status and blood pressure.

Risk Stratification

High risk: Aortic insufficiency associated with NYHA class III to IV symptoms, Marfan syndrome or left ventricular ejection fraction of less than 40%. Such patients ideally should undergo definitive surgical therapy before pregnancy. If patient is already pregnant, termination of pregnancy is recommended.

Low risk: Aortic insufficiency associated with NYHA class I to II symptoms. Such women generally tolerate pregnancy without complications and the natural fall in systolic blood pressure during pregnancy may be beneficial in reducing the regurgitant volume.

Aortic root dilatation in pregnant patients with Marfan syndrome are at increased risk of developing aortic dissection or rupture which usually occur in third trimister or near time of delivery. Patients are at high risk if aortic root diameter is greater than 40mm with approximately 10% probability of developing aortic dissection. Women with marfan syndrome should be counseled against pregnancy and should undergo screening transthoracic echocardiogram to assess the aortic root dimensions. However, replacement of aortic root and ascending aorta may be considered if the aortic diameter exceeds 40 mm in women with marfan syndrome who are contemplating pregnancy. Beta blockers can be used prophylactically throughout pregnancy with labetalol or metoprolol being the preferred drugs. As per AHA/ACC 2006 guidelines, serial transthoracic echocardiogram and regular monitoring of blood pressure throughout the pregnancy with providing adequate analgesia during labor are recommended. Shortening of second stage of labor using various obstetric techniques may be beneficial. In patients with an aortic root diameter greater than 40 mm, severe aortic regurgitation, heart failure or aortic dissection, cesarean delivery with general anesthesia is preferred as it allows optimal hemodynamic control.