Minimizing bleeding complications of percutaneous coronary intervention and glycoprotein IIb-IIIa antiplatelet therapy

Evaluation of Bleeding Complications Associated with Glycoprotein IIb/IIIa Inhibitors

BACKGROUND

Platelet glycoprotein IIb/IIIa inhibitors are used with aspirin and heparin to decrease rates of death, myocardial infarction, and urgent revascularization in patients with acute coronary syndromes.

OBJECTIVE

To determine whether bleeding event rates differed among 3 glycoprotein IIb/IIIa inhibitors prescribed in a high-risk, elderly veteran population and identify risk factors for bleeding.

METHODS

A retrospective chart analysis of patients who received abciximab, eptifibatide, or tirofiban was conducted. χ2 Analysis evaluated the incidence of bleeding complications, and stepwise regression analysis was utilized to identify bleeding risk factors. Parameters evaluated as possible risk factors for bleeding included age, renal function, weight, heparin and glycoprotein IIb/IIIa inhibitor dosing and infusion duration, concomitant antiplatelet and/or anticoagulant medications or disease states, and baseline hemoglobin, hematocrit, or platelet counts.

RESULTS

Of 348 patients whose charts were reviewed, 79 patients were included. There were 37.9% who received abciximab (n = 30), 30.3% who received eptifibatide (n = 24), and 31.6% who received tirofiban (n = 25). Twenty-one bleeding events not related to coronary artery bypass grafting occurred: only 1 major bleed (tirofiban) and 20 minor bleeds. Bleeding rates were not significantly different between groups: abciximab 30% (n = 9), eptifibatide 21% (n = 5), and tirofiban 28% (n = 7). Significant risk factors for bleeding included patient weight, infusion duration, and baseline platelet count (p = 0.024). Patients who bled received significantly more transfusions of packed red blood cells and platelets than patients with no bleeding (p = 0.047).

CONCLUSIONS

Although bleeding complications did not differ significantly between the 3 drugs, several risk factors for bleeding events were identified. A considerable rate of bleeding events occurred in this high-risk patient population.

Left ventricular wall hematoma and cardiac tamponade complicating percutaneous coronary intervention using IIb/IIIa receptor antagonists

A case of intramyocardial hematoma and cardiac tamponade after complicated percutaneous coronary intervention is reported. Hemorrhage as a result of the antiplatelet effect of IIb/IIIa receptor antagonists is the considered underlying mechanism.

Percutaneous ulnar artery approach for primary coronary angioplasty: Safety and feasibility

Transradial approach in primary and rescue angioplasty may be advantageous with respect to the femoral access due to the lower incidence of vascular complications. Ulnar cannulation has been proposed for elective procedures in patients not suitable for transradial approach. We here report on 13 patients undergoing primary angioplasty performed using the transulnar approach. Ulnar access was finally obtained in 10 patients, sheath insertion time ranged from 2 to 5 min, time from arterial puncture to vessel recanalization ranged from 21 to 36 min. Primary angioplasty was successful in all patients. At 30-day echo color Doppler, all ulnar arteries were patent and with a physiologic pattern of flow. Subcutaneous hemorrhage of the forearm was observed in two patients, whereas hematoma, pseudoaneurysm, thrombus, and arterovenous fistula were not observed. In conclusion, transulnar access may represent an additional option in patients undergoing primary angioplasty when the radial artery access site is not available.

Reduction in vascular access site bleeding in sequential abciximab coronary intervention trials

We analyzed vascular access site bleeding from the EPIC, EPILOG, and EPISTENT trials to quantify the decrease in vascular bleeding complications in these three trials, especially those attributable to abciximab. The incidence of combined major and minor vascular access site bleeding in nonabciximab (heparin plus placebo) patients progressively decreased from EPIC (8.2%) to EPILOG (2.9%) to EPISTENT (1.7%; P < 0.001). Combined major and minor vascular access site bleeding in abciximab (heparin plus abciximab) patients decreased from EPIC (20%) to EPILOG (5.8%) to EPISTENT (2.2%; P < 0.001). There were more major vascular access site bleeds with abciximab compared to placebo in EPIC (odds ration 3.2; P < 0.001) but not in EPILOG or EPISTENT. Modified abciximab and heparin dosing and improved vascular access site management strategies have decreased the risk of vascular access bleeding during coronary intervention and have essentially eliminated the excess access site bleeding associated with abciximab.

The nonpeptide glycoprotein IIb/IIIa platelet receptor antagonist SM-20302 reduces tissue plasminogen activator-induced intracerebral hemorrhage after thromboembolic stroke

BACKGROUND AND PURPOSE

Platelet activation and deposition in brain microvessels appear to be key events in the pathogenesis of ischemia-induced neuronal degeneration and behavioral deficits. It has been hypothesized that activated platelets in combination with polymorphonuclear leukocytes and fibrin may play a role in vessel reocclusion leading to the "no-reflow" phenomenon after administration of the thrombolytic tissue plasminogen activator (tPA). We studied the effects of the novel glycoprotein IIb/IIIa platelet receptor antagonist SM-20302 when administered in combination with tPA on infarct and hemorrhage rate and volume to determine whether activated platelets are involved in either infarct or hemorrhage generation after a thromboembolic stroke.

METHODS

One hundred thirty-two male New Zealand White rabbits were included in the present study. Rabbits were embolized by injecting a blood clot into the middle cerebral artery via a catheter. Five or 65 minutes after embolization, SM-20302 (5 mg/kg) was infused intravenously. In drug combination studies, tPA was infused intravenously for 30 minutes starting 60 minutes after embolization, and SM-20302 was administered 5 or 65 minutes after embolization. Postmortem analysis included assessment of hemorrhage, infarct size and location, and clot lysis.

RESULTS

In the vehicle control group, the hemorrhage rate after a thromboembolic stroke was 33%. There was a significant increase (109%) in the hemorrhage rate in the group of rabbits treated with the thrombolytic tPA. SM-20302 by itself did not significantly alter the embolism-induced hemorrhage rate when administered either 5 or 65 minutes after embolism. The SM-20302 groups had a 42% and 33% incidence of hemorrhage in the 5- and 65-minute groups, respectively. In groups treated with a combination of drugs, the SM-20302/tPA group had a 31% and 71% incidence of hemorrhage when SM-20302 was administered 5 and 65 minutes after embolization, respectively. SM-20302 in combination with tPA also significantly increased infarct rate, but not hemorrhage or infarct volume.

CONCLUSIONS

This study suggests that treatment of thromboembolic stroke with the combination of a platelet inhibitor and tPA may have a beneficial outcome on the basis of the following: First, acute administration of SM-20302 did not significantly increase hemorrhage rate. Second, SM-20302 in combination with tPA significantly reduced tPA-induced intracerebral hemorrhage. Third, there appears to be a specific window of opportunity when a platelet inhibitor must be administered to produce a beneficial effect. Overall, on the basis of our results, we hypothesize that the increased rate of intracerebral hemorrhage observed after tPA administration may be partly due to increased reocclusion of cerebral vessels following lysis of the emboli and that reocclusion can be controlled by administration of a platelet inhibitor.

Hemorrhagic transformation following ischemic stroke: significance, causes, and relationship to therapy and treatment

Hemorrhagic transformation (HT) is a frequent consequence of ischemic stroke that becomes more prevalent after thrombolytic therapy. Despite concerns about safety parameters, thrombolytic drugs remain the first course of action available to clinicians for stroke management. However, recent efforts in preclinical studies have attempted to discover other drugs that can lessen the risk of hemorrhage associated with thrombolytic administration. This review focuses on three classes of pharmacologic agents that have shown some promise in animal models of stroke, and can thus be considered as possible candidates for coadministration with thrombolytics in the treatment of stroke. These include the following: 1) spin trap agents, such as alpha-phenyl-N-t-butylnitrone (PBN) that scavenge free radicals; 2) matrix metalloproteinase (MMP) inhibitors, such as BB-94, that prevent membrane and vessel remodeling following ischemia; and 3) the novel glycoprotein (GP) IIb/IIIa platelet receptor antagonist SM-20302. Although these drugs affect different mechanisms, the common denominator seemed to be their effectiveness in reducing the incidence of hemorrhage in response to thrombolytic infusion following an embolic stroke.

Pharmacology: antiplatelet and antithrombin therapy in acute coronary syndromes

Coronary artery disease is the leading cause of death in the United States. According to estimates, 1.25 million acute myocardial infarctions (AMI) occur in the United States each year, 500,000 of which result in death (half of those resulting from sudden death within the first hour). Worldwide, the annual death toll from AMI is approximately 4 million. Inhibitors of platelet function have been associated with decreased morbidity in patients with atherosclerotic cardiovascular disease. Reperfusion of occluded coronary arteries via thrombolytic therapy has markedly reduced mortality and morbidity resulting from events of acute myocardial infarction. This article addresses several antiplatelet and antithrombin agents currently in clinical use throughout the United States.