Risk factors for hospital mortality in valve replacement with mechanical prosthesis.

Objective: Identification of risk factors for cardiac surgery can improve surgical results. Our aim is to identify factors related to increased hospital mortality for patients who underwent mechanical cardiac prosthesis implant.

Methods: Prospective study with retrospective data acquirement study including 335 consecutive patients who underwent at least one implant of St. Jude Medical mechanical prosthesis between December 1994 and September 2005 at the Cardiology Institute of RS. Valve implants were 158 (47.1%) in aortic position, 146 (43.6%) in mitral and 31 (9.3%) in aortic and mitral. The following characteristics were analyzed in relation to hospital death: gender, age, body mass index, NYHA functional class, ejection fraction, type of valve lesion, hypertension, diabetes mellitus, serum creatinine, preoperative arrhythmias, prior heart surgery, CABG surgery, concomitant tricuspid valve surgery and operative priority (elective, urgent or emergent). Logistical regression was used to analyze data and odds-ratio was calculated for individual factors.

Results: During the follow-up there were 13 (3.88%) deaths. In-hospital mortality risk was associated with serum creatinine (P<0.05), ejection fraction < 30% (P<0.001), mitral valve lesion (P<0.05), concomitant CABG surgery (P<0.01), prior cardiac surgery (P<0.01) and reoperation (P<0.01). Increased odd-ratio were related to previous cardiac surgery (5.36; IC95% 0.94-30.56), combined revascularization (5.28; IC95% 1.51-18.36), valvar reoperation (4.69; IC95% 0.93-23.57) and concomitant tricuspid annuloplasty (3.72; IC95% 0.75-18.30).

Conclusion: The mortality rate is within the parameters found in the literature, identifying recognized factors which neutralization by changes in surgical indication and medical management may enable risk reduction.