hirudin and Cerebrovascular-Disorders

Bivalirudin (Angiomax) is a direct thrombin inhibitor used in interventional cardiology due to its several distinct advantages over heparin, most notably a shorter half-life and a potentially superior safety profile. Bivalirudin is also safe to use in patients with active or remote heparin-induced thrombocytopenia. Our objective was to evaluate the safety and tolerability of high-intensity anticoagulation using bivalirudin during neuroendovascular procedures.. The bivalirudin dosing regimens reported in the cardiac literature were modified empirically for two different activated clotting time (ACT) target ranges. The low-dose protocol (ACT of 250 to 300 s) was used for embolization procedures and the high-dose protocol (ACT of 300-350) was employed for angioplasty and stent placement. The bivalirudin treated patients were matched for age, gender, and type of procedure with a random sample of patients who underwent neuroendovascular procedures with the standardized heparin protocol. The thromboembolic and hemorrhagic complications were compared between the two groups and bleeding complications were categorized as major (hemorrhage that was intra-cerebral or resulted in Hb decrease ≥ 5 g/dl), minor, or insignificant.. Bivalirudin was used in 30 patients with high-dose and low-dose bivalirudin protocols used in 26 and 4 patients, respectively. These were compared to the 60 control patients who received heparin. There were no bleeding or thromboembolic complications in the bivalirudin treated patients; however one patient reported a transient headache. In patients treated with heparin, one bleeding complication of a groin hematoma was reported. Also one patient was found to have left-arm weakness following the procedure which was attributed to a new small middle cerebral artery ischemic event.. Our data supports that bivalirudin usage is likely a safe alternative to heparin for high-intensity anticoagulation in neuroendovascular procedures. Further studies are required for more definitive comparisons for efficacy and cost-effectiveness between the two agents.

Topics: Aged; Angioplasty; Antithrombins; Blood Vessel Prosthesis Implantation; Cerebrovascular Disorders; Dose-Response Relationship, Drug; Drug Administration Schedule; Female; Hirudins; Humans; Male; Middle Aged; Peptide Fragments; Recombinant Proteins; Stents; Treatment Outcome

Worldwide, streptokinase continues to be used widely in the treatment of myocardial infarction because it is inexpensive and causes fewer intracranial hemorrhages than other thrombolytic regimens. However, in the Global Use of Strategies to Open Occluded Coronary Arteries (GUSTO-I) trial, the 90-minute angiographic Thrombolysis in Myocardial Infarction (TIMI) trial grade 3 flow rate with streptokinase was 43% lower than that with accelerated tissue plasminogen activator, and there was a higher incidence of death or disabling stroke with streptokinase (7.8% vs 6.9%, p <0.01). In the first Hirulog and Early Reperfusion/Occlusion (HERO-1) trial, 48% of patients given the direct thrombin inhibitor bivalirudin (formerly Hirulog, The Medicines Company) after streptokinase had TIMI 3 patency at 90 minutes, compared with 35% of patients given intravenous heparin (p <0.05). Other angiographic and clinical studies and animal research have shown that early infarct artery blood flow may be increased markedly if a direct thrombin inhibitor is administered before the thrombolytic agent. In the HERO-2 trial, 17,000 patients presenting within 6 hours after the onset of acute myocardial infarction will be given aspirin and randomized to receive either intravenous heparin or bivalirudin before streptokinase is administered. The primary endpoint will be 30-day mortality, and secondary endpoints will include death or myocardial infarction within 30 days, and death or nonfatal disabling stroke. If the thrombin hypothesis is supported by improved clinical outcomes with bivalirudin in the HERO-2 trial, large-scale clinical trials will be needed to evaluate the administration of direct thrombin inhibitors before other thrombolytic regimens.

Topics: Antithrombins; Cerebral Hemorrhage; Cerebrovascular Disorders; Coronary Angiography; Drug Therapy, Combination; Fibrinolytic Agents; Heparin; Hirudin Therapy; Hirudins; Humans; Myocardial Infarction; Peptide Fragments; Recombinant Proteins; Research Design; Streptokinase

Adjunctive therapy for thrombolysis in acute myocardial infarction consists of platelet inhibition with aspirin and thrombin inhibition with heparin. Thrombin inhibition may be improved by the use of hirudin as indicated by experimental and phase II clinical studies. The randomized, double-blind phase III r-Hirudin for Improvement of Thrombolysis study (HIT III) compared a recombinant hirudin (HBW 023) with heparin. The primary end point was the incidence of death or reinfarction.. Seven thousand patients with acute myocardial infarction and a duration of symptoms of less than 6 hours were to be randomized to receive intravenous heparin (70 IU/kg body wt bolus and 15 IU.kg-1.h-1) or hirudin (0.4 mg/kg body wt bolus and 0.15 mg.kg-1.h-1) infused over 48 to 72 hours and adjusted to an activated partial thromboplastin time of 2 to 3.5 times baseline values. In a pilot phase, 1000 patients receiving front-loaded alteplase for thrombolysis were to be recruited by 93 German centers. After enrollment of 302 patients, the trial was stopped after an increased rate of intracranial bleeding was observed in the hirudin group (5 of 148, 3.4%) compared with the heparin group (0 of 154). The overall stroke rate was 3.4% in the hirudin group and 1.3% in the heparin group. Other major bleeding occurred in five versus three patients and ventricular rupture occurred in three versus one patient in the hirudin and heparin groups, respectively. There were 19 in-hospital deaths, with 13 of them from the hirudin group.. Although the number of patients was too small for a definite benefit-risk assessment, at the dosage tested, hirudin in combination with front-loaded alteplase and aspirin may be associated with an increased rate of intracranial hemorrhage. Our findings are consistent with the observations of the GUSTO-II and TIMI-9 trials, where higher doses of another recombinant hirudin were used. Therefore, the therapeutic range of hirudin as an adjunct to thrombolysis may be smaller than previously thought, and reappraisal of dose finding should be considered.

Topics: Adult; Aged; Cerebrovascular Disorders; Double-Blind Method; Female; Hemorrhage; Hirudin Therapy; Hirudins; Humans; Male; Middle Aged; Myocardial Infarction; Partial Thromboplastin Time; Pilot Projects; Prospective Studies; Recombinant Proteins; Survival Analysis; Thrombolytic Therapy

Although intravenous heparin is routinely used in the treatment of patients with acute coronary syndromes, this anticoagulant requires antithrombin III as a cofactor, has no affinity to clot-bound thrombin, and is bound or inactivated by several plasma proteins and platelet factor 4. Recombinant hirudin, the prototypic direct thrombin inhibitor, has been demonstrated in pilot studies to yield improved angiographic and clinical outcomes compared with heparin. We compared these two antithrombins in a large-scale randomized trial.. At 275 participating hospitals in 12 countries, patients within 12 hours from the onset of ischemic chest discomfort with an abnormal ECG were randomly assigned to receive a 72- to 120-hour infusion of heparin (5000-U bolus and 1000- to 1300-U/h infusion, adjusted to activated partial thromboplastin time (APTT) of 60 to 90 seconds or hirudin (0.6-mg/kg bolus and 0.2-mg/kg per hour infusion without aPTT adjustment) on a double-blind basis. Although recruitment of 12,000 patients was planned, the trial was stopped earlier because of an excess of intracerebral hemorrhagic events after 2564 patients were enrolled. The overall incidence of hemorrhagic stroke tended to be higher for patients receiving hirudin (1.3%) compared with heparin (0.7%), P = .11, but the incidence was significantly higher in patients receiving thrombolytic therapy (1264 patients, 1.8%) compared with those who did not (1168 patients, 0.3%), P < .001. The hemorrhagic stroke rate varied by the thrombolytic and antithrombin combination: tissue-type plasminogen activator and heparin, 0.9%; with hirudin, 1.7%; streptokinase with heparin, 2.7%; with hirudin, 3.2%. All these rates are higher than the overall incidence of hemorrhagic stroke in the patients receiving thrombolytic therapy and intravenous heparin in the GUSTO I trial (30,892 patients with rate of 0.7%, 95% CI of 0.6 to 0.8%). Among the 26 patients who had intracerebral hemorrhages, the aPTT was significantly elevated compared with the event-free patients (110 +/- 46 versus 87 +/- 36 seconds at 12 hours of therapy, respectively), P = .03.. At the dose of hirudin tested, there was a trend of an excess of hemorrhagic stroke compared with heparin. Heparin, at a slightly higher dose than previously used in a large-scale trial (approximately 20% increase) was accompanied by a twofold risk of hemorrhagic stroke in patients receiving thrombolytic therapy. With both thrombin inhibitors, the aPTT appears to be a useful index for predicting risk of hemorrhagic stroke in patients receiving thrombolytic therapy.

Topics: Acute Disease; Aged; Cerebral Hemorrhage; Cerebrovascular Disorders; Coronary Disease; Double-Blind Method; Female; Heparin; Hirudin Therapy; Hirudins; Humans; Injections, Intravenous; Male; Middle Aged; Recombinant Proteins; Syndrome; Thrombolytic Therapy

This study sought to investigate the clinical outcomes of patients with and without peripheral artery disease (PAD) in the BRAVO-3 trial with respect to the effect of bivalirudin versus unfractionated heparin (UFH).. PAD is found frequently in patients undergoing transcatheter aortic valve replacement (TAVR) and is reported to confer an increased risk of adverse events. It is unknown whether patients with and without PAD may demonstrate a differential response to bivalirudin versus UFH.. BRAVO-3 was a randomized multicenter trial comparing transfemoral TAVR with bivalirudin versus UFH (31 centers, n = 802). Major adverse cardiovascular events (MACE) were a composite of 30-day death, myocardial infarction, or cerebrovascular accidents (CVA). Net adverse cardiovascular events (NACE) were a composite of major bleeding or MACE.. The total cohort included 119 patients with PAD. Vascular complications occurred significantly more frequently in patients with PAD both in-hospital (25.2 vs. 16.7%; OR 1.68) and at 30 days (29.4 vs. 17.3%; OR 1.99). No significant differences were observed regarding mortality, NACE, MACE, major bleeding or CVA with bivalirudin versus UFH among patients with or without PAD. In patients with PAD, bivalirudin was associated with an increased risk of minor vascular complications at 30 days.. Patients with PAD undergoing transfemoral TAVR did not exhibit an increased risk of any major adverse events, according to the procedural anticoagulant randomization. However, patients treated with Bivalirudin had significantly higher rates of minor vascular complications.

Topics: Aged; Aged, 80 and over; Anticoagulants; Antithrombins; Aortic Valve Stenosis; Catheterization, Peripheral; Cerebrovascular Disorders; Europe; Female; Femoral Artery; Hemorrhage; Heparin; Hirudins; Hospital Mortality; Humans; Male; Myocardial Infarction; North America; Peptide Fragments; Peripheral Arterial Disease; Punctures; Randomized Controlled Trials as Topic; Recombinant Proteins; Retrospective Studies; Risk Assessment; Risk Factors; Time Factors; Transcatheter Aortic Valve Replacement; Treatment Outcome

To evaluate the clinical, angiographic, and cardiac magnetic resonance imaging (cMRI) results in patients with and without diabetes mellitus (DM) undergoing primary percutaneous coronary intervention (PCI) for ST-elevation myocardial infarction (STEMI).. DM has been associated with increased mortality in patients with STEMI, yet the mechanisms underpinning this association have not been completely elucidated.. Overall, 451 patients (51 diabetics) from the INFUSE-AMI trial were studied. They presented with an anterior STEMI due to an occluded left anterior descending artery (LAD) and underwent bivalirudin-supported primary PCI with or without intralesion abciximab and with or without thrombus aspiration. Angiographic baseline and post-procedure parameters, cMRI at 30 days, and clinical follow-up at 30 days and at 1 year were compared between diabetic and nondiabetic patients.. Patients with DM had significantly more comorbidities and more extensive LAD disease than nondiabetics. Primary PCI was equally effective in restoring coronary flow in both groups and the infarct size at 30 days was similar (14.3% [7.1, 24.5] vs. 17.3% [8.1, 23.6], respectively, P = 0.55). Diabetic patients had more major cardiovascular and cerebrovascular events at 1 year (16.5% vs. 8.0%, P = 0.04). Stent thrombosis within 30 days after primary PCI was higher in diabetic than in nondiabetic subjects (4.3% vs. 0.8%, P = 0.03).. Patients with DM presenting with STEMI had a higher baseline risk profile than those without DM. Although reperfusion success and infarct size were similar, diabetic patients experienced more death, reinfarction, stent thrombosis, and revascularization than nondiabetics.

Topics: Abciximab; Aged; Anterior Wall Myocardial Infarction; Antibodies, Monoclonal; Antithrombins; Cerebrovascular Disorders; Coronary Angiography; Coronary Thrombosis; Diabetes Complications; Female; Hirudins; Humans; Immunoglobulin Fab Fragments; Magnetic Resonance Imaging; Male; Middle Aged; Peptide Fragments; Percutaneous Coronary Intervention; Platelet Aggregation Inhibitors; Randomized Controlled Trials as Topic; Recombinant Proteins; Recurrence; Retrospective Studies; Risk Assessment; Risk Factors; Suction; Time Factors; Treatment Outcome

We conducted a study using diffusion-weighted (DWI) and perfusion-weighted (PWI) magnetic resonance imaging (MRI) to evaluate the efficacy of thrombolysis in an embolic stroke model with recombinant tissue plasminogen activator (rt-PA) and hirulog, a novel direct-acting antithrombin. DWI can identify areas of ischemia minutes from stroke onset, while PWI identifies regions of impaired blood flow. Right internal carotid arteries of 36 rabbits were embolized using aged heterologous thrombi. Baseline DWI and PWI scans were obtained to confirm successful embolization. Four animals with no observable DWI lesion on the initial scan were excluded; therefore, a total of 32 animals were randomized to one of three treatment groups: rt-PA (n = 11), rt-PA plus hirulog (n = 11), or placebo (n = 10). Treatment was begun 1 h after stroke induction. Intravenous doses were as follows: rt-PA, 5 mg/kg over 0.5 h with 20% of the total dose given as a bolus; hirulog, 1 mg/kg bolus followed by 5 mg/kg over 1 h. MRI was performed at 2, 3, and 5 h following embolization. Six hours after embolization, brains were harvested, examined for hemorrhage, then prepared for histologic analysis. The rt-PA decreased fibrinogen levels by 73%, and hirulog prolonged the aPTT to four times the control value. Posttreatment areas of diffusion abnormality and perfusion delay were expressed as a ratio of baseline values. Significantly improved perfusion was seen in the rt-PA plus hirulog group compared with placebo (normalized ratios of the perfusion delay areas were as follows: placebo, 1.58, 0.47-3.59; rt-PA, 1.12, 0.04-3.95; rt-PA and hirulog, 0.40, 0.02-1.08; p < 0.05). Comparison of diffusion abnormality ratios measured at 5 h showed trends favoring reduced lesion size in both groups given rt-PA (normalized ratios of diffusion abnormality areas were as follows: placebo, 3.69, 0.39-15.71; rt-PA, 2.57, 0.74-5.00; rt-PA and hirulog, 1.95, 0.33-6.80; p = 0.32). Significant cerebral hemorrhage was observed in one placebo, two rt-PA, and three rt-PA plus hirulog treated animals. One fatal systemic hemorrhage was observed in each of the rt-PA groups. We conclude that rt-PA plus hirulog improves cerebral perfusion but does not necessarily reduce cerebral injury. DWI and PWI are useful methods for monitoring thrombolysis.

Topics: Animals; Anticoagulants; Blood Coagulation; Brain; Cerebral Hemorrhage; Cerebrovascular Circulation; Cerebrovascular Disorders; Hirudins; Intracranial Embolism and Thrombosis; Male; Peptide Fragments; Plasminogen Activators; Rabbits; Recombinant Proteins; Tissue Plasminogen Activator