Anatomical and functional changes after aortic valve replacement with different sizes of mechanical valves

To date, there is no consensus on the selection of type and size of prosthetic valve for aortic valve replacement (AVR). The aim of this study was to compare anatomical and functional changes occurring in the left ventricle after AVR with different sizes of mechanical valves.

A total of 92 patients with serious aortic valve stenosis, who underwent AVR between March 2001 and June 2008 using mechanical valves of different sizes, were retrospectively analysed. The sizes of the mechanical valves were 19, 21, 23 and 25 mm. All patients were assessed preoperatively, and at six months and in the first, third and fifth years postoperatively. The left ventricle was assessed with electrocardiography, echocardiography and telecardiography and compared in the four patient groups, constituted according to the mechanical valve size used.

In all groups, left ventricular mass and mass index, transvalvular aortic gradient, thicknesses of the interventricular septum and posterior wall, and left ventricular endsystolic and end-diastolic diameters had decreased significantly post surgery. Left ventricular ejection fraction and exercise capacity had increased significantly (p < 0.001). The most noteworthy anatomical and functional improvements were seen in patients who had received 23- and 25-mm mechanical valves.

Mechanical valve replacement should not be performed with small size valves because of the higher residual gradient.