Evaluation of platelet kinetics following porcine and mechanical valve replacement.
Because thromboembolic pathogenesis in mechanical prosthetic valves (MP) might involve selective MP platelet consumption with consequent reduced platelet survival, it has been suggested that lowered platelet half-life (T 1/2) detection provides identification of postoperative thrombotic risk. Porcine heterografts (PH) possess less thromboembolic hazards than MP; thus, comparative evaluation of PH versus MP platelet T 1/2 is germane to the test's thrombotic predictive value, yet platelet kinetics in PH require elucidation. Accordingly, 51chromium platelet T 1/2 was determined in 16 patients with substituted valves (10 PH and 6 MP). Average platelet T 1/2 in PH (2.9 +/- 0.6 d) was similar (p greater than 0.05) to MP (3.2 +/- 0.6 d), and both were considerably lower (p less than 0.05) than platelet T 1/2 in normal subjects (NL, 5.1 +/- 0.5 d). Furthermore, platelet T 1/2 was below the lowest NL platelet T 1/2 (4.0 d) in seven PH and three MP patients. Thus, frequency and extent of decreased platelet survival in PH are common and equal to MP. These results indicate that platelet half-life does not afford thromboembolic predictability in patients with mechanical valves and, instead, favors prosthetic-induced physical trauma causing abnormal platelet survival.
D000328:Adult; D000368:Aged; D000818:Animals; D001705:Bioprosthesis; D001777:Blood Coagulation; D001792:Blood Platelets / Q000502:physiology*; D002470:Cell Survival; D005260:Female; D006349:Heart Valve Diseases / Q000601:surgery*; D006350:Heart Valve Prosthesis; D006461:Hemolysis; D006801:Humans; D007700:Kinetics; D008297:Male; D008875:Middle Aged; D011183:Postoperative Complications; D013923:Thromboembolism / Q000209:etiology