Prognostic factors in aortic valve replacement associated with narrow aortic roots. An analysis using the proportional hazard model.
In 80 patients who underwent aortic valve replacement with implantation of a small (21 mm) Medtronic-Hall prosthesis over a period of c. 7 1/2 years, beginning in 1977, prognostic factors were evaluated with use of the proportional hazard model. Twelve variables were considered. Four of them entered the regression model in a time-independent mode. These were preoperative NYHA function class, aetiology (endocarditis), diagnosis ("pure" aortic regurgitation) and aortic cross-clamping time. None of the parameters entered the model in time-related mode. Another multifactorial approach to the proportional hazard model, using a stepwise regression analysis, showed the variables with prognostic value to be aortic cross-clamp time and preoperative NYHA class. Based on this model, predicted 3-year survival ranged from 92% to 45% from the most to the least favourable combination of these prognostic variables. A patient-specific prediction of 3-year survival was formulated.
D001021:Aortic Valve / Q000473:pathology / Q000601:surgery*; D005260:Female; D005500:Follow-Up Studies; D006350:Heart Valve Prosthesis / Q000401:mortality; D006352:Heart Ventricles / Q000503:physiopathology; D006801:Humans; D008297:Male; D008875:Middle Aged; D011183:Postoperative Complications / Q000209:etiology*; D011379:Prognosis; D012044:Regression Analysis; D012306:Risk