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

The role of magnesium in the endothelial dysfunction caused by global ischemia followed by reperfusion: in vitro study of canine coronary arteries

Objective-To study the role of magnesium in the endothelial dysfunction of canine coronary arteries caused by cardiopulmonary bypass (CPB) global ischemia followed by reperfusion. Design-Segments of canine coronary arteries were suspended in organ chambers to measure isometric contraction by prostaglandin F-2alpha, and relaxed by acetylcholine (ACh), sodium fluoride (NaF), calcium ionophore (A(23187)) and sodium nitroprusside (SNP) in crescent concentrations. The investigation protocol had groups with six dogs: CONTROL group (without CPB), CPB group (105 min of CPB without aortic cross-clamping), ISCH group (45 min of CPB with aortic cross-clamping), ISCH/REP group (45 min of aortic cross-clamping followed by 60 min of reperfusion). The coronary relaxations were evaluated with (phase I), without (phase II) and restored magnesium (phase III) to the organ bath. Results-The presence of magnesium in the organ bath was associated with the greater relaxation in response to agonists of the nitric oxide production. The removal of magnesium from the organ bath was associated with the reduction in the intensity of vessel relaxation. The magnesium restoration to the organ bath was associated with the additional reduction in the intensity of relaxation with the exception of NaF that allowed reacquisition of the relaxation observed in the presence of magnesium. Conclusion-This in vitro study demonstrates that magnesium ion favorably influences the nitric oxide production by the coronary endothelium, attenuating the endothelial dysfunction caused by global ischemia followed by reperfusion.37528829