Heart Failure after Aortic Valve Replacement for Aortic Valve Stenosis: Possible Mechanisms

Abstract

Introduction: Aortic valve stenosis imposes a pressure overload on the left ventricle. Congestive heart failure is one of the complications which can appear, even years after the operation. The main questions are: why do patients still develop heart failure? Which types of congestive heart failure can be expected? Which factors related to it are known? Methods: A literature search was performed with the terms "aortic valve disease/replacement AND heart failure". Some secondary references derived from their reference list were also included. The study design of the selected papers differed considerably. Therefore, the analysis is descriptive and concerns factors which can be related to congestive heart failure. Furthermore, surrogate outcomes are ejection fraction, hypertrophy, long axis ventricular function, torsion, left atrial indices, pressures in the left sided heart and in the pulmonary circulation as well as a number of other echocardiographic parameters. Results: It has become clear that decrease in ejection fraction, which is the most commonly used parameter, occurs late in the course of aortic valve stenosis, when damage to the left ventricle has already been inflicted. Several more sensitive imaging and Doppler parameters can demonstrate these changes earlier in the course of aortic valve stenosis. This damage proves to be irreversible, at least in part. This might explain the appearance of heart failure after aortic valve replacement. Although this type of heart failure is mostly "diastolic" in nature, a continuum with the systolic type probably exists, at least in patients with aortic valve stenosis. Conclusions: Damage to the left ventricle in patients with aortic valve stenosis can go unnoticed if ejection fraction is used as sole determinant of left ventricular function, for the timing of operation. Detection of more subtle changes, even in asymptomatic patients with severe aortic valve stenosis should lead to early replacement. This might result in less postoperative heart failure.