Geographic variation and regional trends in adoption of endovascular techniques for cerebral aneurysms
Authors: Smith Gabriel A. , Dagostino Phillip , Maltenfort Mitchell G. , Dumont Aaron S. , Ratliff John K. 
Published: February 2011

Object
Considerable evolution has occurred in treatment options for cerebral aneurysms. Development of endovascular techniques has produced a significant change in the treatment of ruptured and unruptured intracranial aneurysms. Adoption of endovascular techniques and increasing numbers of patients undergoing endovascular treatment may affect health care expenditures. Geographic assessment of growth in endovascular procedures has not been assessed.

Methods
The National Inpatient Sample (NIS) was queried for ICD-9 codes for clipping and coiling of ruptured and unruptured cerebral aneurysms from 2002 to 2008. Patients with ruptured and unruptured cerebral aneurysms were compared according to in-hospital deaths, hospital length of stay, total hospital cost, and selected procedure. Hospital costs were adjusted to bring all costs to 2008 equivalents. Regional variation over the course of the study was explored.

Results
The NIS recorded 12,588 ruptured cerebral aneurysm cases (7318 clipped and 5270 coiled aneurysms) compared with 11,606 unruptured aneurysm cases (5216 clipped and 6390 coiled aneurysms), representing approximately 121,000 aneurysms treated in the study period. Linear regression analysis found that the number of patients treated endovascularly increased over time, with the total number of endovascular patients increasing from 17.28% to 57.59% for ruptured aneurysms and from 29.70% to 62.73% for unruptured aneurysms (p < 0.00001). Patient age, elective status, and comorbidities increased the likelihood of endovascular treatment (p < 0.00001, p < 0.00004, and p < 0.02, respectively). In patients presenting with subarachnoid hemorrhage (SAH), endovascular treatments were more commonly chosen in urban and academic medical centers (p = 0.009 and p = 0.05, respectively). In-hospital deaths decreased over the study period in patients with both ruptured and unruptured aneurysms (p < 0.00001); presentation with SAH remained the single greatest predictor of death (OR 38.09, p < 0.00001). Geographic analysis showed growth in endovascular techniques concentrated in eastern and western coastal states, with substantial variation in adoption of endovascular techniques (range of percentage of endovascular patients [2008] 0%–92%). There were higher costs in patients treated endovascularly, but these differences were likely secondary to presenting diagnosis and site-of-service variations.

Conclusions
The NIS database reveals a significant increase in the use of endovascular techniques, with the majority of both ruptured and unruptured aneurysms treated endovascularly by 2008. Differences in hospital costs between open and endovascular techniques are likely secondary to patient and site-of-service factors. Presentation with SAH was the primary factor affecting hospital cost and a greater percentage of endovascular procedures completed at urban academic medical centers. There is substantial regional variation in the adoption of endovascular techniques.