Increased platelet activation and endothelial dysfunction in patients with atrial fibrillation immediately following percutaneous balloon mitral valvuloplasty.

BACKGROUND: Immediately following percutaneous balloon mitral valvuloplasty (PBMVP), patients have a 3% risk of systemic thromboembolism. HYPOTHESIS: We hypothesized that this may in part be due to an increase in hypercoagulability (as indicated by abnormal coagulation, platelet activation, and endothelial dysfunction) in such patients. METHODS: We measured indices of platelet activation [soluble P-selectin (sPsel), ELISA], endothelial dysfunction [von Willebrand factor (vWf), ELISA], and coagulation (fibrinogen, modified Clauss) in 16 patients (15 women, mean age 59 +/- 10 years) with chronic atrial fibrillation admitted for PBMVP, and 16 healthy age- and gender-matched controls. Blood samples were obtained as follows: (1) peripheral venous samples prior to PBMVP, immediately following PBMVP, and 24 h after PBMVP; and (2) arterial samples prior to and immediately following PBMVP. RESULTS: Patients with mitral stenosis and chronic atrial fibrillation demonstrated significantly higher mean levels of vWf [148 (SD 24) vs. 102 (SD 37); t-test, p < 0.001] and plasma fibrinogen [4.2 (SD 0.8) vs. 3.3 (SD 0.8); p = 0.003] at baseline than matched healthy controls. There was a nonsignificant trend toward lower median sP-sel levels in patients with mitral stenosis [64 (inter quartile range 47-91) vs. 109 (46-128); Mann-Whitney test, p = 0.08]. Following PBMVP, there was a significant increase in venous sP-sel levels immediately post procedure (paired Wilcoxon test, p = 0.03) and at 24 h afterward (p = 0.01). Arterial s-Psel levels correspondingly increased immediately post procedure (p = 0.008). There was a significant increase in mean venous (at 24 h) but not arterial vWf levels post PBMVP. There were no significant changes in mean venous or arterial plasma fibrinogen levels following PBMVP. CONCLUSION: Patients with mitral stenosis and chronic atrial fibrillation have increased plasma levels of vWf and fibrinogen levels compared with healthy controls, suggesting increased endothelial dysfunction and coagulation at baseline in these patients. The increased levels of sP-sel immediately post procedure and at 24 h, in association with increased vWf levels at 24 h after PBMVP, are in keeping with an increase in platelet activation and endothelial dysfunction following PBMVP. These changes may contribute to the increased risk of thromboembolism following PBMVP and suggest the need for adequate antithrombotic therapy following PBMVP.