Re-operation for bioprosthetic aortic structural failure – risk assessment

OBJECTIVE: The predominant complication of bioprostheses is structural valve deterioration and the consequences of re-operation. Prosthesis choice for aortic valve replacement surgery (bioprostheses and mechanical prostheses), is influenced by valve-related complications (mortality and morbidity) of the prosthesis type chosen. The purpose of the study is to determine the mortality and risk assessment of that mortality for aortic bioprosthetic failure. METHODS: From 1975 to 1999, 3356 patients received a heterograft bioprosthesis in 3530 operations. The procedures were performed with concomitant coronary artery bypass (CAB) in 1388 procedures and without in 2142 procedures. Three hundred twenty-two re-operations for structural valve deterioration were performed in 312 patients with 22 fatalities (6.8%). Of the 322 re-replacements, 36 had CAB and 286 had isolated replacement; the mortality was 8.3% (3) and 6.6% (19), respectively. Eleven predictive factors inclusive of age, concomitant CAB, urgency status, New York Heart Association (NYHA) at Re-op and year of Re-op (year periods) were considered. RESULTS: The mortality for 1979-1986 was 6.1% (2/33); 1987-1992, 7.7% (8/104); and 1993-2000, 6.5% (12/185) (pNS). The mortality by urgency status for elective/urgent was 6.4% (19/299); and emergent, 13.0% (3/23) (pNS). The mortality for NYHA I/II was 2.0% (1/50), III 4.2% (8/191) and IV 16.0% (13/81) (P=0.00063), for gender was male 4.6% and female 13.3% (P=0.011), for age at implant 'No' (no re-operation) 51.6+/-12.2 years and 'Yes' (yes re-operation) 59.9+/-7.3 years (P=0.00004), for age at explant 'No' 62.6+/-12.7 years and 'Yes' 70.6+/-6.5 years (P=0.00001), and for age at explant 70 years 12.6% (12/95) (P=0.0011). The predictive risk factor assessment by multivariate regression analysis revealed only NYHA III Odds Ratio 1.7 and IV 7.8 P=0.0082. For the period 1993-2000 of re-operations only gender was significant; age at implant, age at explant, CAB pre-Re-op, CAB concomitant with Re-op, urgency at Re-op, ejection fraction, valve lesion and NYHA at Re-op were not significant. CONCLUSIONS: Bioprosthetic aortic re-operative mortality can be lowered by re-operation in low rather than medium to severe NYHA functional class. The routine evaluation of patients can achieve earlier low risk re-operative surgery.