Reduction of Left Ventricular Hypertrophy after Aortic Valve Replacement for Isolated Aortic Valve Stenosis

Abstract

BACKGROUND Residual left ventricular hypertrophy adversely aRects long-term outcome after aortic valve replacernent. Despite technical advances of increasing prosthesis orifice area, small valves implanted in the unenlarged aortic root may not be significantly less obstructive than the stenotic native valves they replace.

METHOD Forty patients receiving single aortic valve replacement for isolated aotic valve stenosis(without other valvular diseases and coronary artery diseases) were enrolled in this study. The operation was performed from Jan. 1990 to July 1996 in Yonsei Cardiovascular Center. They were implanted with 19, 21, 23, 25mm size valves. Twenty nine were men, and the mean age was 53.3±11.1 years(mean+standard deviation, range 27 to 70 years), and the follow-up duration was 29.5±19.5 months(range 12 to 86 months). Echocardiographic studies were performed before and more than 1 year after the operation. We reviewed the medical histories, clinical symptoms, and echocardiography.

RESULTS 1) The etiology of aotic valve stenosis were congenital bicuspid valve(18 cases, 45%), degenerative(9 cases, 23%), rheurnatic heart disease(8 cases, 20%), and others(5 cases, 13%). Clinical symptoms were dyspnea(39 cases, 98%), angina(19 cases, 45%), and sycope(3 case, 8%). The patients were divided into 19mm group(9 cases, 23%), 21mm group(16 cases, 40%), 23mm group(9 cases, 23%), and 25mm group(6 cases, 15%). The patients replaced with valves of smaller size had significantly smaller surface areas than those replaced with the larger valves. 2) The preoperative LV mass index of smaller valve groups was larger when compared to the larger valve groups. LV mass and mass index decreased in all four groups(albeit significantly in the 19 and 21mrn groups, and without significance in the 23 and 25mm groups). LVEDD, IVST, and PWT were significantly decreased in all four groups. 3) Postoperative peak and mean transvalvular pressure gradients were significantly decreased in all four groups, but were higher in 19mm group than others. Postoperative efFective valve area was significantly smaller in the 19mm group than other groups. 4) No significant differences were observed in left ventricular systolic function parameters both before and after the operation. Clinical symptoms improved in all groups after operation. 5) There was a significant negative correlation between the postoperative valve area index (VAI) and pressure gradients(PG=33.6 17.0xVAI, r=0.71, p<0.001). There was a significant reduction of the LV mass and LV mass index in the patients whose VAI was more than 0.7cm/m.

CONCLUSION In isolated aortic valvular stenosis, aortic valvular replacement produced reduction of left ventricular hypertrophy and clinical improvement. Although 19mm aortic prosthesis continued to create significant obstruction of the left ventricular outflow tract and a smaller effective valvular orifice, nevertheless improvement in LV hypertrophy and clinical symptoms occurred.