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Objectives: The prevalence of significant co-morbidities among patients with abdominal aortic aneurysms (AAA) has contributed to widespread enthusiasm for endovascular AAA repair (EVAR). However, the advantages of EVAR in patients at low risk for open surgical repair (OSR) remain unclear. Our objective is to compare perioperative outcomes of EVAR to OSR in low-risk patients.
Methods: Patients undergoing EVAR and OSR for infrarenal AAA were identified in the 2007-2010 National Surgical Quality Improvement Program datasets. AAA-specific risk stratification, using the Medicare Aneurysm Score (MAS), was used to create matched low-risk (MAS<3) cohorts. Perioperative morbidity and mortality were assessed via crude comparisons of matched groups and regression models.
Results: Of 11753 patients undergoing EVAR, 4339 (37%) were deemed low risk (MAS<3). A matched cohort of 1576 low risk patients was developed from 3804 (41%) undergoing OSR. By definition, the low-risk cohorts included only males aged <75 without significant cardiac, pulmonary, or vascular co-morbidities. Mean age in both low risk groups was 67+/-6 years (P=NS). EVAR patients were more likely to be obese (40.8% vs. 30.4%, P<.001), diabetic (16.2% vs. 13.1%, p=.005), and have a history of cardiac intervention (24.3% vs. 19.2%, P<.001), and/or surgery (22.6% vs. 19.7%, p=.02), steroid use (3.6% vs. 2.0%, p=.002), and bleeding disorders (8.7% vs. 5.9%, p=.001). There were no other differences between the matched cohorts. EVAR was associated with reduced 30-day mortality (0.6% vs. 1.5%, p<0.01), and reduced rates of major complications including: sepsis (0.7% vs. 3.2%, p<0.01), unplanned intubation (1.0 vs. 5.4%, p<.001), pneumonia (0.8% vs. 6.1%, p<.001), acute renal failure (0.4% vs. 2.7%, p<.001), and early reoperation (3.7% vs. 6.0%, p 4 units (2.0% vs. 13.0%, p<.001), cardiac arrest (0.2 vs. 0.8, p=.001), neurological deficits (0.2% vs. 0.5%, p=.032), and urinary tracts infections (1.2% vs. 2%, p=.02).
Conclusion: Our results demonstrate that even among those patients at low risk for OSR, EVAR is associated with reduced perioperative mortality and major complications. While clinical decisions must account for safety and long-term effectiveness, the short-term benefit of EVAR is evident even among patients at the lowest risk for OSR.