Frailty Increases the Risk of 30-day Mortality and Morbidity after Elective Abdominal Aortic Aneurysm Repair Independent of Age and Comorbidities Open Access

Kim, Sung In (2015)

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Background: Frailty, defined as a biologic syndrome of increased vulnerability to stressors, has been linked to adverse outcomes after surgery. We evaluated the effect of frailty on 30-day mortality, morbidity, and failure to rescue (FTR) in patients undergoing elective abdominal aortic aneurysm (AAA) repair.

Methods: Patients undergoing elective endovascular AAA repair (EVAR) or open AAA repair (OAR) were identified in the National Surgical Quality Improvement Program database for the years 2005 to 2012. Frailty was assessed using the modified frailty index (mFI) derived from the Canadian Study of Health and Aging (CSHA), which was categorized into tertiles (low, middle, and high). The primary outcome was 30-day mortality. In addition, post-operative morbidity and the contribution of FTR on mortality were evaluated. The effect of frailty on outcomes was assessed by multivariate regression analysis, which was adjusted for age, American Society of Anesthesiology (ASA) class, and co-morbidities.

Results: Of 23,207 patients, 339 (1.5% overall; 1.0% EVAR and 3.0% OAR) died within 30 days of repair. One or more complications occurred in 2,567 patients (11.2% overall; 7.8% EVAR and 22.1% OAR). Odds ratios (ORs) for mortality adjusted for age, ASA class, and other comorbidities in the group with the highest v. lowest frailty tertiles were 1.9 [95% confidence interval (CI), 1.2-3.0] and OAR (OR, 1.8; 95% CI, 1.5-2.1). There was also a higher FTR rate when post-operative complications occurred, with 1.7-fold higher odds of mortality (95% CI, 1.2-2.5) in the highest tertile of frailty compared with the lowest.

Conclusions: Higher mFI, independent of other risk factors, is associated with higher mortality and morbidity in patients undergoing elective EVAR and OAR. The mortality in frail patients is further driven by FTR from post-operative complications. Frailty evaluation may serve as a useful adjunct for pre-operative risk assessment.

Table of Contents

Background. 1

Methods. 4

Results. 8

Discussion. 12

Summary. 15

Public Health Implications. 16

Future Directions. 17

References. 18

Tables. 21

Figures. 26

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