Thrombi of Different Pathologies: Implications for Diagnosis and Treatment

Abstract

Stroke is the second leading cause of cardiovascular mortality in the modern world, accounting for 80% of strokes of ischemic origin. There are two main etiologies of ischemic stroke: 70% to 80% are caused by carotid atherosclerotic plaque rupture and superimposed thrombus formation, whereas 30% are caused by systemic embolism of a cardiac thrombus (mainly in atrial fibrillation [AF] patients). Therefore, antithrombotic therapy is the cornerstone of stroke treatment. In AF patients, thrombotic risk should be assessed by means of the CHADS2 score. Patients with a score of 0 should be treated with aspirin; for those with a score of 1, oral anticoagulation (target international normalized ratio, 2–3) or aspirin is recommended. For patients with a CHADS2 score ≥2, oral anticoagulation with warfarin should be initiated (unless contraindicated). If warfarin is contraindicated, antithrombotic treatment should be prescribed (the combination of aspirin and clopidogrel seems to be superior to aspirin alone). For primary prevention in atherosclerotic patients, low-dose aspirin is useful only in women older than 45 years who are not at risk for intracranial hemorrhage and do not have gastrointestinal intolerance (a very small but significant effect). For secondary prevention in atherosclerotic patients, antithrombotic therapy should be administered. It is recommended that patients who do not require anticoagulation receive clopidogrel or a combination of aspirin and dipyridamole. Alternatively, aspirin alone or triflusal may be used. Within 4.5 h of onset of acute stroke, thrombolytic therapy (recombinant tissue plasminogen activator) must be injected urgently (unless contraindicated). Dabigatran is a new oral anticoagulant (competitive thrombin inhibitor) with a promising role in stroke prevention; at low doses, it is noninferior to warfarin for stroke prevention and is safer, whereas at high doses, it is superior to warfarin in stroke prevention with the same incidence of bleeding. Percutaneous left atrial appendage occluders recently were approved for systemic embolism prevention. The use of warfarin after implantation is still under discussion. Dronedarone, a new antiarrhythmic agent, has been shown to decrease cardiovascular mortality and stroke in patients with AF. Carotid endarterectomy surgery is indicated in symptomatic patients with stenosis greater than 70% and in selected patients with 50% to 70% stenosis. Currently, carotid endarterectomy surgery is superior to carotid angioplasty and stenting.