ROLE OF ANGIOGRAPHY FOLLOWING ANEURYSM SURGERY

The postoperative angiograms in 66 patients who underwent craniotomy f or clipping of 78 cerebral aneurysms were reviewed. Indications for ur gent postoperative angiography included neurological deficit or repeat subarachnoid hemorrhage. Routine postoperative angiograms were carrie d out in the remaining patients. Postoperative angiograms were reviewe d to determine the incidence of unexpected findings such as unclipped aneurysms, residual aneurysms, and unforeseen major vessel occlusions. Logistic regression analysis was used to test if the following were f actors that predicted an unexpected finding on postoperative angiograp hy: aneurysm site or size; the intraoperative impression that residual aneurysm was left or a major vessel was occluded; intraoperative aneu rysm rupture; opening or needle aspiration of the aneurysm after clipp ing; or development of a new neurological deficit after surgery. Kappa values were calculated to assess the agreement between some of these clinical factors and unexpected angiographic findings. Unexpected resi dual aneurysms were seen in three (4%) of the 78 occlusions. In additi on, three aneurysms were completely unclipped (4%); these three patien ts were returned to the operating room and had their aneurysms success fully obliterated. There were nine unexpected major vessel occlusions (12%); six of these resulted in disabling stroke and two patients died . Of six major arteries considered to be occluded intraoperatively and shown to be occluded by postoperative angiography, two were associate d with cerebral infarction. Logistic regression analysis showed that a new postoperative neurological deficit predicted an unforeseen vessel occlusion on postoperative angiography. Factors could not be identifi ed that predicted unexpected residual aneurysm or unclipped aneurysm. The inability to predict accurately the presence of residual or unclip ped aneurysm suggests that all patients should undergo postoperative a ngiography. Since a new postoperative neurological deficit is one fact or predicting unexpected arterial occlusion, intraoperative angiograph y may be necessary to help reduce the incidence of stroke after aneury sm surgery. With study of more patients or of factors not examined in this series, it may be possible to select cases more accurately for in traoperative or postoperative angiography.