Aortic valve replacement for aortic stenosis in patients with small aortic root

Patients with aortic stenosis and small aortic ostia are getting more and more common in our practice. They now constitute a third of our aortic valve replacement (AVR) material. The patients are usually elderly women with small heart and body dimensions, sometimes making it difficult to implant sufficiently large valve prostheses.

We describe a non-selected series of 254 patients from a geographically defined area who underwent AVR during a six year period (1989-1995) and who were considered to have small aortic annulus, defined as patients receiving 19 and 21 mm prostheses. Mean age was 71 years, 42% were over the age of 75, 88% were women and 32% underwent concomitant coronary artery bypass grafting (CABG). Fifty-nine (23%) required pericardial patch enlargement of the aortic root to accommodate sufficiently large prostheses. Prostheses used included Björk-Shiley Monostrut (n = 54), CarboMedics (n = 58), St. Jude (n = 74), Sorin Bicarbon (n = 2), Mitroflow pericardial (n = 26) and Carpentier-Edwards pericardial valve (n = 40). Pericardial valves were usually employed in patients 75 years and older.

Operative mortality was 3.1%. There was no mortality in patients undergoing isolated AVR. Late mortality, after a mean observation period of two years, was 4.9%. At Doppler echocardiography one week postoperatively, 95% had a gradient across the prosthesis that was considered to be within acceptable limits (resting mean gradient < 30 mmHg). In the remaining patients higher gradients indicated some degree of prosthesis-patient mismatch.

To avoid this mismatch the surgical considerations include choosing a prosthesis with a large effective orifice area, using an optimal valve implantation technique (partly or completely supra-annular placement of the prosthesis) and, if this is not enough, enlarging the annulus with an outflow patch.