Antithrombotic Therapy for Cerebrovascular Disorders: Idiopathic Hypertrophic Subaortic Stenosis
Idiopathic Hypertrophic Subaortic Stenosis (IHSS)
IHSS is associated with a low incidence of stroke (0.6%/year) unless AF coexists. Patients with stroke and IHSS should be monitored for intermittent AF, particularly if the left atrium is enlarged, and other causes of stroke (infective endocarditis) sought.
Nonbacterial Thrombotic Endocarditis
Brain embolism occurs in about 30% (range, 9-42%) of patients with nonbacterial thrombotic endocarditis (NBTE). NBTE occurs in about 1% (range, 0.4-2.2%) of consecutive autopsies. Bland, platelet-fibrin thrombi form on the atrial surface of the mitral valve and ventricular surface of the aortic valve, usually along the lines of valve closure, Vegetations are usually multiple and smaller than 5 mm but may be as large as 1.5 cm. The diagnosis of NBTE-associated embolism should be considered when multiple brain and/ or systemic emboli occur in patients with malignancy or wasting illness, especially if coagulation abnormalities or thrombophlebitis coexists. Embolism may antedate recognition of malignancy. Cardiac murmurs are present in only a minority of patients. Echocardiography sometimes demonstrates larger vegetations. Treatment has not been systemically studied; it is not known whether platelet antiaggregating agents or anticoagulants effectively reduce embolism. fully
Calcific Aortic Stenosis
Before attributing brain embolism to calcific aortic stenosis, one should carefully exclude atherosclerotic vascular disease, AF, coexistent mitral valve disease, and infective endocarditis as the cause. However fibrin-platelet deposits have been demonstrated on disrupted valvular endothelium, and calcific retinal emboli have been observed in patients with calcific aortic stenosis. The optimal treatment is unknown, although platelet-antiaggregating agents have been advocated.
Some 27-55% of patients with left atrial myxoma experience embolism, primarily to the brain. Myxomas are the only cardiac tumors that regularly embo-lize, owing to their intracavitary location and friability. Atrial myxomas are readily detected by echocardiography or cardiac CT. Surgical therapy is usually curative, and there appears to be no role for antithrombotic therapy for this uncommon source of brain emboli.
Category: Antithrombotic Therapy
Tags: antithrombotic therapy, cardioembolic source, cerebrovascular disorders