COAGULATION ACTIVITY AND EMBOLI COUNTS IN PATIENTS WITH PROSTHETIC CARDIAC VALVES

Background and Purpose The underlying embolic material detected by tra nscranial Doppler ultrasound in patients with prosthetic heart Valves remains unknown. We undertook this study to evaluate the relation betw een the number of Doppler emboli signals and the activity of the coagu lation system. Methods Patients with various types of prosthetic valve s (n=120) and patients in atrial fibrillation (n=20) were monitored fo r 30 minutes using transcranial Doppler with a 2-MHz probe. The plasma concentrations of cross-linked D-dimer, antithrombin-III, and thrombi n-antithrombin III complex were measured. Results No correlation betwe en the levels of any of the hematologic parameters and the number of e mboli was demonstrated in the studied groups. The D-dimer levels were significantly higher in patients with mechanical prosthetic valves wit h an international normalized ratio under 2.0 com-pared with those wit h an international normalized ratio between 2 and 3.5 or above 3.5, an d in patients with Medtronic-Hall versus Bjork-Shiley or Carpentier-Ed wards valve prostheses. Conclusions The lack of correlation between th e activity of the coagulation system and the number of Doppler emboli in patients with prosthetic valves suggests that the underlying emboli c material in these patients is not thrombotic. Our results also sugge st that an increase of the anticoagulation intensity to an internation al normalized ratio above 3.5 does not result in a further decrease of the activity of the unstimulated coagulation system in patients with mechanical prosthetic valves.