Comparison of Three Methods Evaluating Platelet Survival Time in Patients with Prosthetic Heart Valve

In determining the mean life span in 51Cr platelet survival studies, the survival parameters could be estimated by visual fitting (graphical method). In addition, 3 methods have been recommended for computing the mean survival time (1): the weighted mean of linear estimate or logarithmic estimate, the truncated exponential model and the gamma model. In our study these 2 later models and graphical method were used for evaluating platelet survival time (PST). The study was a randomized controlled clinical trial (2) carried out with patients with aortic or mitral valve replacement, operated by the surgeons of Hopital Cardiologique, Lyon, France.