Impact of introducing endovascular aneurysm repair on treatment strategy for repair of abdominal aortic aneurysm - National hospital organization network study in Japan

Background: The objective of the present study was to assess the hypothesis that the introduction of endovascular aneurysm repair (EVAR) into Japan has expanded the indication of abdominal aortic aneurysm (AAA) repair without increasing surgical mortality. Methods and Results: From 10 national hospitals, we registered a total of 2,154 consecutive patients (Open surgery [OS]: n=1,577, EVAR: n=577) over 8 years, divided into 4 time periods: Group I (2005-2006: n=522), Group II (2007-2008: n=475), Group III (2009-2010: n=551), Group IV, (2011-2012: n=606). Mean age increased over the 4 time periods (P<0.0001). The incidences of COPD, smoking history, history of abdominal surgery and concomitant malignancy significantly increased as well, while the numbers of patients with preoperative shock or high ASA status reduced over time. The proportion of EVAR in AAA repair increased from: 0% in Group I, 11.6% in Group II, 41.0% in Group III, to 48.8% in Group IV (P<0.0001). Early mortality was 0.8% in the EVAR and 3.4% in the OS (P<0.001) groups. Survival rates among the 4 groups free of all-cause death and aneurysm-related death at 1 year were 92.1-96.3% (P=0.1555) and 95.5-96.8% (P=0.9891), respectively. Multiple logistic regression analysis for surgical death failed to demonstrate survival advantage of EVAR over OS. Conclusions: Introduction of EVAR expanded the indication of AAA repair without increasing mortality, while high risk for anesthesia and emergency cases reduced over time.