Left ventricular architecture after valve replacement due to critical aortic stenosis: an approach to dis-/qualify the myth of valve prosthesis-patient mismatch?

Objectives: Left ventricular hypertrophy in patients with critical aortic s tenosis (AS) is an adaptive process that compensates for high intracavitary pressure and reduces systolic wall stress followed by an increase in myoca rdial masses. In the present prospective clinical trial, we investigated lo ng-term compensatory changes in left ventricular geometry and function afte r aortic valve replacement using mechanical bileaflet prostheses with the m ain emphasis on the small-sized aortic annulus and valve prosthesis-patient mismatch. Methods: A total of 58 patients: with critical AS were assigned to the following groups according to the predictive value of prosthetic val ve area index (VAI): group EXMIS: 29 patients (VAI less than or equal to 0. 99), expected mismatch; group NOMIS: 29 patients (VAI less than or equal to 0.99), no mismatch. At controls T-0 (before operation/operation (OP), T-1 and T-2 (4 and 20 months after OP) the left ventricular geometry was record ed by means of Imatron(R) electron beam tomography and the transprosthetic velocities were measured by echocardiography. Results: Statistical analysis showed a consistent reduction in the absolute (P = 0.04) and indexed (P = 0.04) left ventricular myocardial mass for both cohorts; furthermore, there was a significant difference between EXMIS and NOMIS patients concerning t he factors, time and mass reduction (P = 0.005), because of distinct baseli nes. A logistic regression report revealed preoperative cardiac output, abs olute left ventricular myocardial mass, perfusion, body surface area and th e native valve orifice area as predicting coefficients and factors for a mi nimum mass reduction of 25%. We explain a mathematical formula that turned out to he the most sensitive for correctly classified factors. Conclusions: The left ventricular geometry and transprosthetic Velocities resulted in t he same postoperative recovery for both EXMIS and NOMIS patients. The prese nted data showed that valve prostheses-patient mismatch had no influence in several stepwise logistic regression models. We conclude that modern mecha nical bileaflet prostheses allow both acceptable hemodynamics and recovery of left ventricular hypertrophy, even in small aortic annuli. (C) 2001 Else vier Science B.V. All rights reserved.