Contemporary Incidence, Outcomes and Survival Associated with EVAR Conversion to Open Repair Among Medicare Beneficiaries
Abstract
OBJECTIVE: The widespread application of endovascular abdominal aortic aneurysm repair (EVAR) has ushered in an era of requisite post-operative surveillance and the potential need for re-intervention. The national prevalence and results of EVAR conversion to open repair however, remain poorly defined. The purpose of this analysis was to define the incidence of open conversion and its associated outcomes. METHODS: The SVS VQI EVAR registry linked to Medicare claims via Vascular Implants Surveillance and Interventional Outcomes Network (VISION) was queried for open conversions after initial EVAR procedures from 2003-2016. Cumulative conversion incidence within up to five years following EVAR and outcomes following open intervention were determined. Multivariable logistic regressions were used to identify independent predictors of conversion and mortality. RESULTS: Among 15,937 EVAR patients, 309 (1.9%) underwent an open conversion: 43% (n=132) early (<30-days) and 57% (n=177) late (>30-days). The longitudinally observed rate of conversion was constant over time, as well as by geographic region. Independent predictors of conversion included female sex (HR 1.49, p<.001), aneurysm diameter >6.0 cm at the time of index EVAR (HR 1.74, p<.001), non-elective repair (compared to elective presentation: HR 1.72, p<.001), and aorto-uni-iliac repairs (HR 2.19, p<.001). In contrast, adjunctive operative procedures such as endo-anchors or cuff extensions (HR 0.62, p=.06) were protective against long-term conversion. Both early (HR 1.6, p<.001) and late (HR 1.26, p=.07) open conversions were associated with significant 30-day (total cohort-15%) and 1-year mortality (total cohort-25%). Patients undergoing open conversion experienced high rates of 30-day readmission (42%), cardiac (45%), renal (32%) and pulmonary (30%) complications. CONCLUSIONS: This large registry based analysis is among the first to document the incidence and outcomes for open conversion after EVAR in a national cohort with long-term follow-up. Importantly, women, patients with large aneurysms, and complex anatomy, as well as urgent/emergent EVARs are at increased risk for open conversion. It appears that more conversions are performed in the early post-operative period, despite perceptions that conversion is a delayed phenomenon. In all instances, conversion is associated with significant morbidity and mortality and highlights the importance of appropriate patient selection at the time of index EVAR.
