ximelagatran and Cerebral-Hemorrhage

Fibrinolysis is the reference treatment for most myocardial infarctions with ST-segment elevation; alternatives are angioplasty, with or without stent. The earlier fibrinolysis is performed (preferably before hospitalization), the more effective it is. It can be optimized by adjuvant antiplatelet therapy, such as aspirin, and probably by anticoagulant treatment as well. Because fibrinolytic therapy is accompanied by intensive thrombin generation and activation, immediate and continuous adjunctive simultaneous heparin therapy is recommended. The efficacy of subcutaneous low-molecular-weight heparin (LMWH) HBPM) is at least equivalent to that of intravenous unfractionated heparin (UFH), but its risk of severe (but not cerebral) hemorrhage is greater. Bolus LMWH on the other hand is associated with an increased risk of cerebral hemorrhage. Antithrombotic treatment thus appears optimal with bolus UFH at fibrinolysis and for at least 48 hours afterwards. An alternative after this bolus might be subcutaneous enoxaparin until discharge. Because the major drawback of both types of heparin is their rebound activation of thrombosis, oral anticoagulants are recommended thereafter. The combination of anticoagulant treatment + (low-dose) aspirin is not superior to aspirin alone when the target INR is below 2. Adequate anticoagulation with INRs greater than 2.0 consistently improves angiographic and clinical outcome. Bleeding (except intracerebral) is significantly increased whether the INR is greater than or less than 2.0. Other treatments are being investigated. Pentasaccharide (anti-Xa) combined with fibrinolysis seems to reduce reocclusion more effectively than UFH. Oral postinfarction treatment with ximelagatran (a thrombin inhibitor), combined with aspirin, is associated with fewer cardiovascular events than aspirin alone. More studies are needed.

Topics: Anticoagulants; Aspirin; Azetidines; Benzylamines; Cerebral Hemorrhage; Coronary Thrombosis; Drug Therapy, Combination; Factor Xa; Fibrinolytic Agents; Follow-Up Studies; Forecasting; Hemorrhage; Heparin; Heparin, Low-Molecular-Weight; Humans; Injections, Intravenous; Injections, Subcutaneous; Myocardial Infarction; Myocardial Ischemia; Platelet Aggregation Inhibitors; Randomized Controlled Trials as Topic; Risk Factors; Time Factors; Treatment Outcome

Atrial fibrillation (AF) is now regarded as the arrhythmia for which patients are hospitalized the most frequently, an arrhythmia that is responsible for significant morbidity and mortality. Of particular importance is that the arrhythmia is associated with a significant incidence of thromboembolism which may induce disabling and incapacitating strokes, sometimes fatal. In the past, it was thought that in patients with AF restoration and maintenance of sinus rhythm prevent the development of strokes, a presumption that has not been vindicated by controlled clinical trials. On the other hand, over many decades, it has been established that appropriate anticoagulation especially with warfarin can reduce stroke rate in nonvalvular AF by about 70%, and mortality by 26%. Aspirin reduces stroke rate by 26%, mortality by about 10%. Thus, in AF oral anticoagulants have become the focal point of therapy for the prevention of strokes and the safety and efficacy of such a therapy has been established by controlled clinical trials; moreover, the subsets of patients with AF in whom anticoagulation is mandatory have been defined on the basis of defined risk factors. Warfarin is now the anticoagulant of choice although its limitations are considerable in terms of drug-drug interactions, narrow range of therapeutic index requiring strict monitoring of intensity of anticoagulation, among other limitations which influence compliance of therapy with the agent. In this review, the continuing role of warfarin in the prevention of stroke in patients with AF is discussed as a background for the development of newer anticoagulants. The issue is of particular importance in the older patients, in whom the development of safer antithrombotic therapies remain a major challenge. In this context, the potential role of the direct thrombin inhibitors hold promise for the future and the evolving data on leading compounds of this class which may be competitive with warfarin are discussed.

Topics: Aged; Ambulatory Care Facilities; Anticoagulants; Aspirin; Atrial Fibrillation; Azetidines; Benzylamines; Cerebral Hemorrhage; Drug Design; Factor Xa Inhibitors; Fibrinolytic Agents; Humans; Prospective Studies; Randomized Controlled Trials as Topic; Risk Factors; Self Care; Stroke; Thrombin; Warfarin

Warfarin prevents stroke in atrial fibrillation (AF); however, concerns regarding international normalized ratio control and hemorrhage limit its use in the elderly. The oral direct thrombin inhibitors (DTIs) are potential alternatives to warfarin, offering fixed dosing without drug and dietary interactions and the need for international normalized ratio monitoring. Although ximelagatran, a DTI studied in the Stroke Prevention using an ORal Thrombin Inhibitor in atrial Fibrillation trials, has been withdrawn, development of other DTIs continues. We report our experience in elderly high-risk AF patients on ximelagatran compared with warfarin therapy.. Data from patients with AF and stroke risk factors randomized in Stroke Prevention using an ORal Thrombin Inhibitor in atrial Fibrillation III and V trials to ximelagatran or warfarin were analyzed for stroke/systemic emboli, bleeding, and raised alanine aminotransferase levels in those >or=75 (n=2804) and <75 (n=4525) years.. Ximelagatran was as effective as warfarin in reducing stroke/systemic emboli in the elderly (2.23%/y with ximelagatran vs 2.27%/y with warfarin) as in younger patients (1.25%/y vs 1.28%/y). Total bleeds were significantly lower with ximelagatran compared with warfarin in elderly (40% vs 45%, P=0.01) and younger (27% vs 35%, P<0.001) patients. Raised alanine aminotransferase values (>3-fold elevation) among ximelagatran patients were more common in older (7.5% old vs 5.3% young) patients, particularly women (9.5% elderly women vs 6.1% elderly men).. In high-risk elderly AF patients, ximelagatran is as effective as warfarin with less bleeding, but alanine aminotransferase elevations are common, particularly in elderly women. Oral DTIs for stroke prevention show promise in elderly patients.

Topics: Administration, Oral; Age Factors; Aged; Aged, 80 and over; Alanine Transaminase; Anticoagulants; Atrial Fibrillation; Azetidines; Benzylamines; Cerebral Hemorrhage; Double-Blind Method; Embolism; Female; Humans; Intracranial Thrombosis; Male; Middle Aged; Sex Characteristics; Sex Factors; Stroke; Thrombin; Treatment Outcome; Up-Regulation; Warfarin