Evaluating the Effectiveness and Clinical Outcomes of Endovascular Aneurysm Repair-First Approach for Ruptured Abdominal Aortic Aneurysm in Japan

Abstract

Purpose: To verify the validity of an endovascular aneurysm repair (EVAR)-first strategy for treating patients with ruptured abdominal aortic aneurysm (rAAA) in Japan. Materials and methods: This study was conducted on 2 groups of patients with rAAA who underwent surgical treatment at 3 hospitals in the Kanagawa Prefecture, Japan, between January 2007 and September 2016. The open surgical treatment group comprised patients with rAAA who underwent open surgical treatment before January 2012; their data were retrospectively collected from their medical records. The EVAR-first strategy group comprised patients with rAAA who underwent treatment based on the Shonan rAAA protocol (SRAP; the standard protocol-based EVAR-first strategy) in or after February 2012; their data were collected prospectively. The short- and long-term treatment outcomes of both groups were compared. In addition, a risk score-based sensitivity analysis (one-to-one matching) was conducted on both groups using a caliper with 0.2 standard deviations of the score. Results: Of the 163 patients with rAAA, the open surgical and EVAR-first strategy groups comprised 53 and 110 patients, respectively (EVAR: 91.8%, open repair: 8.2%). The 30-day postoperative mortality rate differed significantly, being 42% for the open surgery group and 25% for the EVAR-first strategy group (odds ratio: 0.44, 95% confidence interval: 0.20–0.97). The postoperative survival rates at 6 months, 1 year, and 3 years were 66%, 48%, and 58% for the EVAR-first group, respectively, and 51%, 66%, and 48% for the open surgery group, respectively (p=0.072). In a matched cohort analysis (n=50), the 30-day postoperative mortality rate was 22% for the EVAR-first group and 44% for the open surgery group (odds ratio: 0.35, 95% confidence interval: 0.14–0.90). The postoperative survival rates at 6 months, 1 year, and 3 years were 76%, 76%, and 63% for the EVAR-first group, respectively, and 48%, 45%, and 45% for the open surgery group, respectively (p=0.003). Conclusion: The SRAP-based EVAR-first strategy for rAAA yielded significantly better treatment outcomes than the open surgical strategy. These findings suggest that EVAR should be considered the primary treatment option for rAAA, given its potential to reduce early mortality rates. Clinical Impact Multicenter retrospective analysis of prospectively collected registry data was done to compare treatment outcomes of two groups of ruptured abdominal aortic aneurysm patients open surgery and endovascular-aneurysm-repair (EVAR)–first strategy (Shonan ruptured abdominal aortic aneurysm protocol). EVAR-first group showed better outcomes: lower 30-day mortality (25% vs. 42%), higher survival rates at 6 months, 1 year, and 3 years. Take home Message: The study supports the use of the EVAR-first strategy with the Shonan Protocol for treating ruptured abdominal aortic aneurysms in Japan, showing improved outcomes, reduced 30-day postoperative mortality, and better long-term survival rates compared to the conventional approach.