Safety of immediate reversal of anticoagulation by protamine to reduce bleeding complications after infarct artery stenting for acute myocardial infarction and adjunctive abciximab therapy

Infarct artery stenting with adjunctive abciximab therapy is widely used treatment for patients with acute myocardial infarction (AMI). However, bleeding complications have been associated with a worse clinical outcome. Randomized trials in elective patients have shown that postprocedural protamine administration is safe and associated with a significant reduction in bleeding complications. The aim of the current study was to evaluate in STEMI patients undergoing primary percutaneous coronary intervention (PCI) with abciximab and stenting whether immediate reversal of anticoagulation by protamine is safe and associated with a reduction in the occurrence of bleeding complications. From January 2004 to June 2005, 254 patients with STEMI had immediate reversal of anticoagulation by protamine administration after infarct artery stenting and received abciximab therapy without heparin infusion (Group 1). These patients were compared with a control group of 265 patients (June 2002–December 2003) treated with the standard heparin therapy: bolus in order to achieve an activated coagulation time of 250–300 s during PCI plus 12-h infusion (7 UI/kg/h; Group 2). We excluded patients undergoing IABP implantation. The two groups were similar in all baseline characteristics. There were no differences in in-hospital mortality, reinfarction, urgent target vessel revascularization, stroke or acute or subacute stent thrombosis, while Group 1 patients showed a lower incidence of major bleeding complications (ACUITY scale: 1.1 vs. 4.0%, P = 0.035) and a shorter length of hospital stay (3.5 ± 1.7 vs. 4.0 ± 1.6 days, P = 0.002) as compared with heparin treated patients. Among patients undergoing primary stenting with abciximab administration, immediate post-PCI reversal anticoagulation by protamine without associated heparin infusion is safe and associated with a significant reduction in major bleeding complications

Quantitative in vitro comparison of the thrombogenicity of commercial dental implants

BACKGROUND Dental implants often have surface modifications that alter surface topography and chemistry to improve osseointegration and thereby increase treatment predictability. Surface contact-induced blood coagulation is associated with the onset of osseointegration. PURPOSE To quantitatively evaluate the thrombogenicity of two commercially available dental implants that have similar surface roughness but different surface chemistry. MATERIAL AND METHODS Two commercially available dental implants with anodized or sandblasted acid-etched surfaces were evaluated for thrombogenic properties. Thrombogenicity was assessed by incubating implants for 1 hour in fresh, partially heparinized blood followed by hemocyte quantification, microscopic evaluation, and quantification of thrombogenic biomarkers. RESULTS Fibrin coverage was significantly higher on the anodized surface compared with the sandblasted acid-etched surface (P < 0.0001). Platelet and white blood cell attachment followed a similar pattern. The increased thrombogenicity was confirmed based on a significant increase in the levels of the coagulation cascade biomarkers, thrombin antithrombin complex, and β-thromboglobulin (all P < 0.05). CONCLUSION Dental implants with comparable roughness but differing surface chemistry had differing extents of blood contact activation. These data suggest that surface chemistry from anodization augments implant thrombogenicity compared with that from sandblasting and acid-etching, which could have implications for osseointegration