Perioperative evaluation of primary hemostasis in patients undergoing mitral valve repair

Introduction: no data exist on the prevalence of primary hemostatic defects and acquired von Willebrand disease in mitral valve prolapse with severe regurgitation. Methods: Primary hemostasis was evaluated by PFA-100, von Willebrand factor Antigen (vWf: Ag) and Ristocetin cofactor (vWF: RiCof) assays in a prospective observational trial. Sixty-five consecutive patients with mitral regurgitation (study group) or aortic stenosis (control group) who were operated for mitral valve repair or aortic valve replacement were enrolled in the study. Results: There were no differences in Closure Time in the two groups at all time points. The concentration of plasma vWf: Ag was within normal limits in all patients preoperatively; after surgery, a significant increase was observed in both groups from baseline (199 +/- 144 mcg/dL vs. 295 +/- 141 mcg/dL in the study group, p=0.002; 243 +/- 141 mcg/dLl vs 338 +/- 154 mcg/dL in the control group, p=0.009). The ratio of vWF: RiCof to vWF: Ag was slightly decreased preoperatively in both groups (ratio=0.91) and showed a marked increase in the postoperative period (ratio=0.22) as, probably, new hemostatically effective large multimeric forms of vWF were released. Conclusions: Patients who present for surgery with a valvular pathology with high shear stress have some degree of primary hemostasis defect; nevertheless, the potent stimulus of surgery and the correction of the underlying disease allow quick restoration of vWF activity and normalization of PFA-100.