Long-term outcomes with the On-X bileaflet mitral valve: clinical events up to 17 years in 661 patients.

OBJECTIVES

This study reports long-term clinical outcomes-up to 17 years-among patients undergoing mitral valve replacement with the On-X bileaflet mechanical valve. Prior data regarding long-term outcomes with the On-X mitral valve have been limited.

METHODS

This retrospective observational study included all patients who underwent mitral valve replacement with the On-X (Standard or Conform-X) valve at 2 major Spanish cardiac surgery centres between 2001 and 2018. The primary study end point was freedom from death. The secondary study end points included surgical mortality and freedom from any valve-related events. Data were obtained from an institutional database, medical records review, direct telephone interviews or the Spanish population registry. Statistical and Kaplan-Meier analyses were performed.

RESULTS

A total of 661 patients (mean age 63.1 ± 10.9 years, 63% female) were followed for a mean of 5.6 years (range, 0-17.4 years). Survival at 5, 10 and 15 years was 85%, 71% and 63%, respectively. Surgical mortality was 7.3% (48/661). The linearized rate of global mortality was 1.3% patient-year. Freedom from reoperation was 97%, 95% and 92% at 5, 10 and 15 years, respectively; freedom from anticoagulation-related events was 94%, 89% and 89%, respectively. Multivariable analysis showed that mortality increased with total length of stay, age, smoking history, severe pulmonary hypertension and a permanent pacemaker. Patients who received the On-X 25 -mm valve had decreased long-term survival relative to patients who received other On-X valve sizes, possibly due to underlying risk factors.

CONCLUSIONS

Patients in this study showed good long-term survival and freedom from valve-related events.