Long-term implications of elective evar that is non-compliant with clinical practice guideline diameter thresholds

Abstract

Objective: Compliance with Society for Vascular Surgery (SVS) abdominal aortic aneurysm (AAA) clinical practice guideline (CPG)-diameter thresholds is variable for endovascular aneurysm repair (EVAR). To evaluate the implications and appropriateness of repairs that are noncompliant with current guidelines, we investigated the long-term outcomes, adherence to imaging follow-up, and associated health care costs in patients undergoing EVAR for AAA who do or do not meet recommended diameter thresholds.

Methods: All patients receiving elective EVAR from 2003 to 2016 in the SVS Vascular Quality Initiative with linked Medicare claims were reviewed. Weekend procedures and isolated iliac aneurysms, as well as symptomatic and ruptured presentations, were excluded. Diameter thresholds for noncompliant repairs were defined as: men <55 mm; women <50 mm who did not have an iliac diameter ≥30 mm. We evaluated adherence to postoperative imaging surveillance, reimbursement amounts, reintervention, rupture, and all-cause mortality. We defined an EVAR quality metric as performance of the index procedure with freedom from conversion to open repair, 5-year rupture-free survival, and adherence to minimum imaging surveillance (at least one computed tomography scan documented between 6 and 24 months postoperatively).

Results: Among 19,018 elective EVARs, 35% did not meet CPG diameter thresholds (26% within 5 mm of threshold). The rate of noncompliant repairs increased over time (24% in 2003 vs 36% in 2016; P < .001). Patients undergoing noncompliant repairs were younger, less likely to have multiple comorbidities, and more likely to receive EVAR with adherence to instructions for use criteria (89% vs 79%; P < .001). Patients undergoing noncompliant repairs had greater 5-year freedom from reintervention (86% vs 81%; P < .001), rupture-free survival (94% vs 92%; P = .01), and overall survival rates (71% vs 61%; P < .001) compared with repairs that complied with CPG diameter thresholds. Although noncompliant repairs had higher rates of 1-year imaging surveillance, overall differences were modest (68% vs 65%; P = .003). Importantly, for the entire cohort, follow-up imaging surveillance decreased over time (93% in 2003 vs 63% in 2014; P < .001). Notably, although noncompliant repairs had higher rates of achieving the composite quality metric compared with compliant repairs (43% vs 38%; P < .001), failure occurred with a significant majority of all repairs.

Conclusions: Compliance with SVS-endorsed CPG diameter thresholds for elective EVAR is poor, and rates of noncompliance are increasing. Noncompliant repairs appear to be offered more commonly to patients with fewer comorbidities and favorable anatomy, and these repairs are associated with improved rates of reintervention, rupture, and survival compared with procedures meeting CPG diameter thresholds. Importantly, noncompliant repairs fail to meet minimum quality standards in a majority of cases, which underscores the need for further policies to improve the overall quality and appropriateness of AAA care delivery nationally.

Keywords: Aortic aneurysm; EVAR; Guidelines; Repair threshold.