Aortic insufficiency in renal disease


 * Associate Editor-in-Chief: Varun Kumar, M.B.B.S., Lakshmi Gopalakrishnan, M.B.B.S.

Overview
Aortic insufficiency in patients with end stage renal disease can be due to either valvular calcification or infective endocarditis.

Valvular calcification
Valvular/annular thickening, and calcification of heart valves occur commonly in patients undergoing dialysis, thereby leading to valvular regurgitation and/or stenosis. Hyperparathyroidism occurring secondary to renal disease is one of the most significant predisposing factor for valular calcification. Aortic insufficiency is seen less commonly than mitral or tricuspid insufficiency. In a study on 75 patients with end stage renal disease (ESRD) undergoing hemodialysis, 38% of patients were found to have developed aortic insufficiency.

The severity of aortic regurgitation varies with alterations in preload and afterload which are dependent on:
 * 1) The volume status of the patient (this has the most significant effect)
 * 2) Degree of left ventricular function
 * 3) Medications such as antihypertensives

Aortic regurgitation worsens in the setting of elevated systolic blood pressure and increased afterload conditions which are seen in ESRD. Attaining optimal intravascular volume and blood pressure control with aggressive ultrafiltration and antihypertensives should be the therapeutic goals in these patients because, by decreasing afterload, the regurgitant fraction decreases and thereby improves left ventricular systolic function.

Infective Endocarditis
Infective endocarditis is another cause for aortic insufficiency. This may result from either causing perforation in the valves or by causing incomplete closure of the valves due to a vegetation lying between the cusps which prevents their apposition. Patients undergoing dialysis are at increased risk of developing infective endocarditis. The incidence of endocarditis has been described as 2%- 5% in patients regularly undergoing hemodialysis. This could be due to repeated vascular access (through arteriovenous fistulas and indwelling catheters) and immunocompromised state resulting from uremia. Presence of underlying valvular heart disease further increase the risk of endocarditis.

In a 10 year analysis of 16 patients undergoing long term hemodialysis who satisfied Duke's criteria for infective endocarditis, Staphylococcus species was found to be the most common species in 11 patients with aortic valve involved in 4(25%) patients.

In another retrospective study in 123 patients, among 85% of patients with vavlular insufficiency(mitral and aortic valve) secondary to infective endocarditis approximately 40% were undergoing hemodialysis. 23.4% of the patients had pure aortic insufficiency.

Removal of catheters and prompt treatment is recommended when endocarditis is suspected. Click here for detailed treatment of endocarditis. The survival rates among patients with hemodialysis induced infective endocarditis is poor.