Anesthetic considerations

Significant progress has been made during recent years in the surgical treatment of aortic aneurysm. Surgical techniques have been developed and improved for successful treatment regardless of the type, location, and extent of the disease, thus, operative mortality has steadily declined.1 The management of patients undergoing such procedures represents a major challenge for the anesthetist. The typical victim of aortic disorders is advanced in years and has generalized arteriosclerotic vascular disease including coronary artery and/or cerebral vascular insufficiency, as well as hypertension, diabetes, and renal dysfunction. The surgical procedure can be strenuous for these patients for it may last many hours and there may be significant blood loss, volume shifts and electrolyte and temperature changes. Aortic cross-clamping and declamping are particularly hazardous for the patient. Hypertension, myocardial ischemia, and arrhythmias have occurred after application of the cross clamp, while unclamping often results in severe hypotension with myocardial, cerebral or renal ischemia. 2 Pathogenesis of aneurysms The etiology of aneurysms is diverse. Syphilis, once a major cause of arterial disease, has declined in importance but it is the basis of about 5-10% of aneurysms, especially in the ascending aorta. Trauma; Marfan's syndrome, a hereditary disease characterized by arachnodactyly, deformities of the thoracic cage, dislocated lens, and often thoracic aneurysms; Takayasu's syndrome, also known as pulseless disease, a bizarre connective tissue disease characterized by stenosis or occlusion of vessels arising from the aortic arch; and other rare degenerative vascular diseases constitute another 10%, especially in younger patients. Congenital aneurysms are rare. The large "residue" resulting from arterial disease accounts for more morbidity and mortality in the sixth and seventh decades of life than all other diseases combined. This residue refers to arterioand athero-sclerosis, still thought to be an inevitable accompaniment to aging. Genetic factors are strong determinants of at least three factors predisposing to atherosclerosis: serum lipids, blood pressure, and blood sugar. About 10% of the world population has, or will have, hypertension. Whether essential or secondary to other disease:s, notably renovascular disease, hypertension raises the incidence of cerebrovascular accidents (CVA) and myocardial infarction (MI). Twenty percent of vascular patients have diabetes mellitus, and arteriosclerosis is the most common complication of diabetes.