Prospective evaluation of hemostatic predictors of subacute stent thrombosis after coronary Palmaz-Schatz stenting

Objectives. This study sought to investigate hemostatic predictors of subacute occlusive coronary stent thrombosis. Background. Better hemostatic monitoring may improve anti-thrombotic therapy after stenting. Methods. In 140 consecutive patients undergoing Palmaz-Schatz stent implantation for suboptimal angioplasty results, we obtained serial blood samples immediately before and daily for 12 days after stenting. We prospectively tested the hypothesis that subacute stent thrombosis was more frequent if the surface expression of the inducible fibrinogen receptor on platelets (flow cytometry) or the concentration of plasma fibrinogen or that of the prothrombin fragments F₁₊₂ before stent implantation exceeded the 75th percentile of the entire study cohort. Results. All five stent occlusions encountered during the study occurred in patients with platelet fibrinogen receptor expression above the 75th percentile. Thus, the rate of stent occlusion differed significantly between the groups defined by platelet fibrinogen receptor expression (14.3% vs. 0%, p = 0.0008). In both the group with fibrinogen concentration and that with F₁₊₂ concentration above the 75th percentile, three stent occlusions occurred. Between the groups defined by these variables, the rate of stent occlusion did not differ significantly (8.6% vs. 1.9%, p = 0.10). Logistic regression analysis, including angiographic and hemostatic variables, confirmed platelet fibrinogen receptor expression as an independent predictor of stent occlusion (p = 0.020). Stent occlusion could not be predicted by the time course of any of the hemostatic variables. Conclusions. Platelet fibrinogen receptor expression is an independent predictor of subacute stent occlusion. However, fibrinogen and F₁₊₂ concentrations do not show a strong relation to the risk of stent occlusion.