Predicted shortfall in open aneurysm experience for vascular surgery trainees

Abstract

Objective: Since the introduction of endovascular aneurysm repair (EVAR), the volume of open aneurysm repair (OAR) has steadily declined since 2000. The introduction of next-generation devices and branched and fenestrated endograft technology continues to increase the anatomic applicability of EVAR, further decreasing the need for OAR. This study models the decline in OAR and uses historical trends to forecast future decline in volume and its potential effect on vascular surgery training.

Methods: An S-curve modified logistic function was used to model the effect of introducing a new technology (EVAR) on the standard management of abdominal aortic aneurysm (AAA) with OAR starting in the year 2000, when an International Classification of Diseases, Ninth Revision, code was first introduced for EVAR. Patients who underwent EVAR and OAR for AAA were determined using the Nationwide Inpatient Sample from 1998 to 2011. Weighted samples and data from the United States Census Bureau were used to extrapolate these numbers to estimate population statistics. The number of cases completed at teaching hospitals was calculated using the Nationwide Inpatient Sample, and Accreditation Council for Graduate Medical Education case logs were used to forecast the number of cases completed by vascular surgery trainees.

Results: The highest number of OAR cases in this study was 42,872 in 2000 compared with just 10,039 in 2011. This was mirrored by a rise in EVAR from 2358 cases in 2000 (5.2%) to 35,028 in 2011 (76.5% by volume). Of the OAR volume in 2011, 6055 cases (60.3%) were completed at teaching institutions. An S-curve model with a correlation coefficient of R2 = 0.982 predicted 3809 open AAA cases at teaching hospitals by 2015, 2162 by 2020, and 1231 by 2025. When compared with the 2011 Accreditation Council for Graduate Medical Education National Resident Report, vascular surgery residents had 44.4% utilization with regard to OAR (2690 cases covered of 6055 total). When combined with the increase in vascular surgery trainees and lower number of open repairs, vascular fellows will complete about 10 OAR cases in 2015 and five OAR cases in 2020.

Conclusions: The decreasing number of OAR cases will limit exposure for vascular trainees, who may be ill equipped to treat patients who require open repair beyond 2015. Additional methods for providing OAR training should be explored.