SELECTION OF CEREBRAL ANEURYSMS FOR TREATMENT USING GUGLIELMI DETACHABLE COILS - THE PRELIMINARY UNIVERSITY-OF-ILLINOIS AT CHICAGO EXPERIENCE

OBJECTIVE: We present our initial experience with Guglielmi detachable coils (GDCs). The aim of this study was to determine the criteria for aneurysms, ruptured or unruptured, that are suitable for this techniq ue. The importance of aneurysm geometry and its impact on the final re sults are discussed. METHODS: A retrospective analysis of 329 patients with 339 cerebral aneurysms that were treated at the University of Il linois Hospital at Chicago from May 1994 to tune 1997 was conducted. O ne hundred eighty-five patients were treated surgically, and 144 were selected for treatment using GDCs. Of the 144 patients selected for GD C treatment, 55 patients with 55 aneurysms were admitted during the ac ute phase of subarachnoid hemorrhage and 89 patients with 97 aneurysms had nonruptured aneurysms or were treated after clinical recovery of previously ruptured aneurysms. All procedures were performed with the patients under general anesthesia and with systemic heparinization usi ng live simultaneous biplane roadmapping, with the exception of the fi rst four patients. These patients were treated before the installation of the biplane system. The percentage of aneurysm occlusion was deter mined at the end of each procedure. Follow-up angiography was schedule d to be performed at 6 months, 1 year, and 2 years after treatment. PA TIENT SELECTION: For the initial 25 patients (Group 1), selection for coiling was restricted to nonsurgical candidates or patients in whom c oiling was thought to be the best treatment choice, based on medical c ondition and location of the aneurysm. The geometry of the aneurysm wa s not considered to be an important factor in the selection for coilin g. The remaining patients (Group 2) were selected for coiling based on aneurysm geometry, as determined by pretherapeutic angiography. Aneur ysms that were considered to be favorable for coiling included those t hat had a dome-to-neck ratio of at least 2 and an absolute neck diamet er less than 5 mm. RESULTS: The initial 25 patients (Group 1) were tre ated from May 1994 to February 1995. There were high morbidity and mor tality rates, with 56% of the treated aneurysms occluded at 6 months. The remaining patients (Group 2) consisted of 119 patients with 123 an eurysms. There was no mortality directly related to the coiling proced ure, and permanent morbidity was limited to 1.0%. Three patients (2.5% ) developed transient neurological deficits secondary to the procedure , and seven patients (5.8%) experienced periprocedural complications t hat did not result in neurological sequelae. The morphological results were strongly correlated to the geometry of the aneurysms, with a com plete occlusion rate of 72% among the acutely ruptured aneurysms and 8 0% among the nonacute aneurysms, when patients were selected for treat ment based on the geometry of the aneurysms and the dome-to-neck ratio was at least 2. The occlusion rate dropped to 53% when selection was not based on aneurysm geometry and the dome-to-neck ratio was less tha n 2. A summary of the morphological outcomes for the Group 2 patients shows that 86% of the aneurysms that initially underwent coiling using GDCs were completely occluded (78% by coils alone, 3.0% in conjunctio n with surgery, and 5.0% with parent artery occlusion). Residual small neck remnants were present in 11% of the Group 2 aneurysms (3.0% were scheduled for surgical treatment of residual neck remnant growths not amenable to further endovascular treatment, and 8% were scheduled for initial 6-mo follow-up examinations). Death resulting from unrelated causes before initial follow-up occurred in 3.0% of the patients. CONC LUSION: These preliminary results suggest that using GDCs is a safe te chnique resulting in low morbidity and mortality rates for the treatme nt of intracranial aneurysms in appropriately selected patients. The p ercentage of complete aneurysm occlusion is related to the density of coil packing, which is strongly dependent on the geometry of the aneur ysm. Optimal results are obtained when the dome-to-neck ratio is at le ast 2.