Multivariate analysis for operative mortality in obstructive prosthetic valve dysfunction due to pannus and thrombus formation.

The objective of the present study was to investigate the risk factors for early hospital mortality in reoperations performed for obstructive prosthetic valve dysfunction. Between January 1994 and April 2005, 63 patients underwent reoperation for obstructive prosthetic valve dysfunction. The mean age of the patients was 40.3 +/- 12.8 years. The mitral valve was replaced in 47 (74.6%) patients, the aortic valve in 6 (9.5%) patients, and both valves in 10 (15.9%) patients. Forty-three (68.2%) patients underwent emergency reoperations. Early hospital mortality occurred in 13 (20.6%) patients. The ethiology of the valve dysfunction was pannus formation in 45 (71.4%) patients and thrombus formation in 18 (28.6%). Pannus and thrombus were localized at the atrial side of the prosthetic valve in 15 (23.9%) patients, at the ventricular side in 13 (20.6%), and at both sides in 35 (55.5%). Inadequate anticoagulation was diagnosed in 28 of 63 (44.4%) patients. The mean INR level in these 28 patients was 1.43 +/- 0.24. In multivariate analysis, the only risk factor for early hospital mortality was left ventricular ejection fraction (P = 0.015; Odds: 0.000, 95% CI: 0.000-0.043). It is concluded reoperations for prosthetic valve dysfunction have a high mortality rate. This study revealed that left ventricular dysfunction is the major determinant of surgical mortality in patients requiring reoperation for valve dysfunction due to pannus or thrombus.