Reoperation for bioprosthetic mitral structural failure: risk assessment.

BACKGROUND The predominant complication of bioprostheses is structural valve deterioration and the consequences of reoperation. The purpose of the study was to determine the mortality and risk assessment of that mortality for mitral bioprosthetic failure. METHODS AND RESULTS From 1975 to 1999, 1 973 patients received a heterograft bioprosthesis in 2 152 operations. The procedures were performed with concomitant coronary artery bypass (CAB) in 694 operations and without in 1 458 operations. There were 481 reoperations for structural valve deterioration performed in 463 patients with 34 fatalities (7.1%). Of the 481 re-replacements, 67 had CAB and 414 had isolated replacement; the mortality was 11.9% (8) and 6.3% (26), respectively. Eleven predictive factors inclusive of age, concomitant CAB, urgency status, New York Heart Association (NYHA; reoperation), and year of reoperation (year periods) were considered. The mortality from 1975 to 1986 was 9.8% (6/61), from 1987 to 1992 it was 10.8% (20/185), and from 1993 to 2000 it was 3.4% (8/235) (I versus III P=0.0458, II versus III P=0.0047). The mortality by urgency status was elective/urgent 6.0% (26/436) and emergent 17.8% (8/45) (P=0.00879). The mortality was NYHA I/II 0.00% (0/37), III 5.1% (14/273), and IV 11.7% (20/171) (P=0.0069). The predictive risk factors by multivariate regression analysis were age at implant, odds ratio (OR) 0.84 (P=0.0113); age at explant, OR 1.2 (P=0.0089); urgency, OR 2.8 (P=0.0264); NYHA, OR 2.5 (P=0.015); 1975-1986 versus 1993-2000 of reoperations, OR 5.8 (P=0.0062); and 1987-19 92 versus 1993-2000, OR 4.0 (P=0.0023). For the period 1993 to 2000 of reoperations, only age at implant and age at explant were significant; NYHA class, urgency status, and concomitant CAB were not significant. CONCLUSIONS Bioprosthetic mitral reoperative mortality can be lowered by reoperations on an elective/urgent basis in low to medium NYHA functional class. The routine evaluation of patients can achieve earlier low risk reoperative surgery.