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An important study has emerged from the Vascular Section of the General Surgery Division. In studying data of patients undergoing endovascular aneurysm repair (EVAR) for abdominal aortic aneurysms (AAA), they found that women are at more risk for complications and mortality than men.
The team comprises Drs. Eric Endean, Nick Abedi, Eleftherios Xenos, Ehab Sorial, and David Minion. The sixth author is Daniel Davenport, PhD who was responsible for collecting and analyzing the data.
The data derived from the American College of Surgeons National Surgical Quality Improvement Program (ACS NSQIP). Records from a total of 173 hospitals throughout the United States were analyzed for the calendar years 2005-2007. Dedicated nurse reviewers at each hospital used standardized definitions and systematic samples to collect the data. They used 55 preoperative risk factors, eight procedure and intraoperative variables, and 30-day outcomes. The outcomes examined were mortality, any morbidity as defined by the occurrence of one or more of 21 postoperative events, and length of hospital stay.
There were 3662 patients: 647 women and 3015 men. The data revealed numerous gender differences in preoperative risk variables. Women were more likely to undergo emergent surgery, be functionally dependent, be either underweight or morbidly obese, and have severe chronic obstructive pulmonary disease (COPD). Women required more iliac or brachial artery exposures, femoral crossover grafts, blood transfusions, and had longer operative times. Additionally, women were more likely to undergo tube graft or aorto-uni-iliac/femoral grafts. These intraoperative variables suggest that EVAR repair in women was technically more challenging.
The data revealed that overall morbidity was 11.9% with women at 17.8% and men at 10.6%. The incidence of adverse events in each of six complication subgroups was significantly higher in women. Multivariate analysis demonstrated that female gender was an independent predictor of longer length of hospital stay, infectious complications, wound occurrences, and postoperative transfusion.
WHY SO?
The study cannot identify cause and effect but based on the results, the authors hypothesize why women have poorer outcomes after undergoing EVAR. Aneurysms are more prevalent in men and as such, there may be a delay in diagnosis in women. As seen in the data, women have a higher incidence of emergent repair and are known to be associated with poorer outcomes. As well, women have more co-morbid conditions than men, suggesting that they were not as fit for undergoing surgery. Finally, the data suggest that EVAR was more technically challenging (neck angulation, size of neck, small iliac diameter, associated occlusive disease and tortuosity of the iliac arteries) in women than men, adding to the risk.
While this important study raises a number of questions, it definitively represents an accurate picture of current 30-day outcomes for patients undergoing EVAR in the United States.
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