Review of medical prevention of vasospasm after aneurysmal subarachnoid hemorrhage: A problem of neurointensive care

CEREBRAL VASOSPASM REMAINS a devastating medical complication of aneurysmal subarachnoid hemorrhage (SAH). It is associated with high morbidity and mo rtality rates, even after the aneurysm has been secured surgically or radio logically. A great deal of experimental and clinical research has been cond ucted in an effort to find ways to prevent this complication. The literatur e includes extensive coverage of in vivo animal model studies of SAH and va sospasm. These experimental studies have contributed to tremendous advances in the understanding of the mechanisms leading to cerebral vasospasm. Most of the experimental settings, however, have demonstrated varying levels of ability to predict accurately what occurs in human SAH. Therefore, althoug h animal models have been developed to test new therapies, most of the trea tment effects have been shown to be less compelling when trials have been c onducted in clinical settings. The interpretation of current literature is complicated further by the imprecise estimation of the incidence of cerebra l vasospasm, which is due to various degrees of clinical expression, rangin g from the absence of symptoms in the presence of increased blood flow velo cities at transcranial Doppler or vessel diameter reduction at angiography to neurological manifestations of severe ischemic deficits. In addition, a change over time in the incidence pattern of human SAH and vasospasm, possi bly related to improved surgical techniques and overall patient management, may have occurred. This topic review collects the relevant literature on c linical trials investigating prophylactic therapies for cerebral vasospasm in patients with aneurysmal SAH and emphasizes the need for large clinical trials to confirm the results derived from clinical experience. In addition , it points out some experimental therapies that may hold promise in future clinical trials to prevent the occurrence of vasospasm.