Aortic Valve Replacement With 17-mm Mechanical Prostheses: Is Patient–Prosthesis Mismatch a Relevant Phenomenon? (original) (raw)

2011, Annals of Thoracic Surgery

Background. We sought to evaluate the long-term performance of a consecutive cohort of patients implanted with a 17-mm bileaflet mechanical prosthesis. Methods. Between January 1995 and December 2005, 78 patients (74 women, mean age ‫؍‬ 71 ؎ 12 years) underwent aortic valve replacement with a 17-mm mechanical bileaflet prosthesis (Sorin Bicarbon-Slim and St. Jude Medical-HP). Preoperative mean body surface area and New York Heart Association class were 1.6 ؎ 0.2 m 2 and 2.6 ؎ 0.8, respectively. Preoperative mean aortic annulus, indexed aortic valve area, and peak and mean gradients were 18 ؎ 1.6 mm, 0.42 cm 2 /m 2 , 89 ؎ 32 mm Hg, and 56 ؎ 21 mm Hg, respectively. Patients were divided into two groups, according to the presence (group A, 29 patients) or absence of patient-prosthesis mismatch (group B, 49 patients). Patient-prosthesis mismatch was defined by an indexed effective orifice area less than 0.85 cm 2 /m 2. Results. Overall hospital mortality was 8.8%. Follow-up time averaged 86 ؎ 44 months. Actuarial 5-year and 10-year survival rates were 83.7% and 65.3%, respectively. The mean postoperative New York Heart Association class was 1.3 ؎ 0.6 (p < 0.001). Overall indexed left ventricular mass decreased from 163 ؎ 48 to 120 ؎ 42 g/m 2 (p < 0.001), whereas average peak and mean prosthesis gradients were 28 ؎ 9 mm Hg and 15 ؎ 6 mm Hg, respectively (p < 0.001). Early and long-term mortality were similar between the two groups as well as longterm hemodynamic performance (mean peak gradient was 28 mm Hg and 27 mm Hg in group A and B, respectively, not significant); left ventricular mass regression occurred similarly in both groups (indexed left ventricular mass at follow-up was 136 ؎ 48 and 113 ؎ 40 in group A and B, respectively; not significant). Conclusions. Selected patients with aortic stenosis experience satisfactory clinical improvement after aortic valve replacement with modern small-diameter bileaflet prostheses.