REST AND EXERCISE HEMODYNAMICS OF AN EXTENDED STENTLESS AORTIC BIOPROSTHESIS

Background and aims of the study: Aortic valve surgery in patients wit h a narrow aortic root remains a clinical problem. The Extended Biocor (R) Stentless porcine bioprosthesis was specifically designed to allow widening of the aortic annulus in patients with narrow aortic roots. The aim of this prospective study was to evaluate the hemodynamic perf ormance of this prosthesis. Methods: Serial Doppler echocardiography w as used in 50 patients (mean age 77 years, range: 60 to 87 years) duri ng a 15-month follow up after aortic valve replacement. Valve hemodyna mics were also assessed in 30 patients at 15 months after surgery, dur ing increased flow rates induced by a supine bicycle exercise test. Re sults: Of these patients, 60% received valves sized 23 mm or smaller. The mean pressure difference before hospital discharge was 13.8 +/- 5. 8 mmHg and this decreased by 40% during the first six months. During t he same period there was a significant increase in effective orifice a rea and a decrease in left ventricular mass. Symptom-limited supine ex ercise increased cardiac output by 65% while the mean pressure differe nce increased only slightly (from 8.1 +/- 3.2 to 11.9 +/- 3.6 mmHg). T rivial aortic regurgitation (grade 1+) was detected in 12% of patients at 15 months follow up. All patients who were in NYHA functional clas s III or IV before surgery were in class I or II after surgery. Conclu sions: We conclude that the Extended Biocor(R) Stentless prosthesis sh ows low Doppler-derived transvalvular pressure gradients both at rest and during exercise, and also when small-sized valves are employed. Do ppler echocardiography, showing low incidence of aortic regurgitation and early regression of left ventricular hypertrophy, demonstrate the beneficial hemodynamic performance of this valve.