Adverse events after clipping of unruptured intracranial aneurysms: the NSQIP unruptured aneurysm scale

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The complex decision analysis of unruptured intracranial aneurysms entails weighing the benefits of aneurysm repair against operative risk. The goal of the present analysis was to build and validate a predictive scale that identifies patients with the greatest odds of a postsurgical adverse event.


Data on patients who underwent surgical clipping of an unruptured aneurysm were extracted from the prospective National Surgical Quality Improvement Program registry (NSQIP; 2007–2014); NSQIP does not systematically collect data on patients undergoing intracranial endovascular intervention. Multivariable logistic regression evaluated predictors of any 30-day adverse event; variables screened included patient demographics, comorbidities, functional status, preoperative laboratory values, aneurysm location/complexity, and operative time. A predictive scale was constructed based on statistically significant independent predictors, which was validated using both NSQIP (2015–2016) and the Nationwide Inpatient Sample (NIS; 2002–2011).


The NSQIP unruptured aneurysm scale was proposed: 1 point was assigned for a bleeding disorder; 2 points for age 51–60 years, cardiac disease, diabetes mellitus, morbid obesity, anemia (hematocrit < 36%), operative time 240–330 minutes; 3 points for leukocytosis (white blood cell count > 12,000/μL) and operative time > 330 minutes; and 4 points for age > 60 years. An increased score was predictive of postoperative stroke or coma (NSQIP: p = 0.002, C-statistic = 0.70; NIS: p < 0.001, C-statistic = 0.61), a medical complication (NSQIP: p = 0.01, C-statistic = 0.71; NIS: p < 0.001, C-statistic = 0.64), and a nonroutine discharge (NSQIP: p < 0.001, C-statistic = 0.75; NIS: p < 0.001, C-statistic = 0.66) in both validation populations. Greater score was also predictive of increased odds of any adverse event, a major complication, and an extended hospitalization in both validation populations (p ≤ 0.03).


The NSQIP unruptured aneurysm scale may augment the risk stratification of patients undergoing microsurgical clipping of unruptured cerebral aneurysms.

ABBREVIATIONS CPT = Current Procedural Terminology; ICD-9-CM = International Classification of Diseases, 9th Revision, Clinical Modification; ISUIA = International Study of Unruptured Intracranial Aneurysms; NIS = Nationwide Inpatient Sample; NSQIP = National Surgical Quality Improvement Program.

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Article Information

Correspondence Rose Du: Brigham and Women’s Hospital and Harvard Medical School, Boston, MA.

INCLUDE WHEN CITING Published online March 15, 2019; DOI: 10.3171/2018.12.JNS182873.

Disclosures Dr. Gormley: proctor for Codman. Dr. Aziz-Sultan: proctor for Medtronic, Covidien, and Codman.

© AANS, except where prohibited by US copyright law.



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    Variations in the crude rates (and associated standard errors) of adverse events (A), postoperative stroke or coma (B), extended hospitalization (C), and nonroutine hospital discharge (D) by differences in the NSQIP unruptured aneurysm scale divisions.




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