Comparison of low-pressure versus standard-pressure fixation Carpentier-Edwards bioprosthesis. Discussion

Intermediate-phase clinical results of 51 low-pressure (LP) and 234 standard-pressure (SP) fixation porcine Carpentier-Edwards (CE) valves implanted between 1977 and 1991 were compared for valve-related events. Group similarities included New York Heart Association functional class, ejection fraction, and sex. Patients with SP valves were younger (mean age, 58 versus 68 years ; p = 0.0001). There were 20 in-hospital deaths (8.6%) in the SP valve group and 5 (9.8%) in the LP valve group (p = 0.79). Follow-up was 99%, with a mean of 104 months in the SP valve group versus 55 months in the SP valve group (p = 0.0001). The actuarial survival rate was 48.2% and 22.3% at 10 and 15 years, respectively, in the SP valve group and 34.1% at 10 years in the LP valve group (p = 0.42). Freedom from events at 5, 10, and 15 years in the SP valve group and at 5 years in the LP valve group was as follows : for late valve-related events, 86.3%, 51.4%, and 20.2%, respectively, in the SP valve group versus 85% in the LP valve group (p = 0.44) ; for valve-related death, 96.4%, 93.6%, and 87.3% in the SP valve group versus 100% in the LP valve group (p = 0.20) ; for structural valve failure, 96%, 68%, and 35% in the SP valve group versus 100% in the LP valve group (p = 0.09) ; and for reoperation, 95%, 61%, and 30% in the SP valve group versus 92% in the LP valve group (p = 0.82). In conclusion, this study revealed no significant statistical difference between LP and SP valves. In the LP valve group, structural valve failure/valve-related death was not observed, perhaps indicating a more favorable result. Absolute verification of this trend awaits long-term follow-up.