Endovascular and open surgical repair of abdominal aortic aneurysms: A comparative analysis of western and chinese studies

Abdominal aortic aneurysms (AAA) are life-threatening serious conditions that require effective and quick management. Although it is generally acknowledged that patients with AAA obtain the greatest benefit from endovascular repair (EVAR) compared to open surgical repair (OSR), there are few comparisons between the surgical approaches in Western versus Chinese patients. We aimed to perform a meta-analysis of studies in which EVAR was compared with OSR in the management of abdominal aortic aneurysms. We searched the Western literature through PubMed, OVID and Web of Science from 1991 until December 2018 and the Chinese-language literature from 1998 until December 2018. We pooled the results in January 2019 based on standardized inclusion and exclusion criteria and analyzed them using a conventional meta-analysis. Forty-five English papers with 31,074 AAA patients and twenty-one Chinese studies with 1,405 patients were included in this study. Chinese subjects were more likely to undergo endovascular repair than Western subjects (44.5% versus 41.5%, P = 0.012). The 30-day post-discharge mortality rate in Western studies was significantly lower for EVAR than for OSR (odds ratio (OR) = 0.481, P < 0.001). However, there was no significant reduction in the 30-day mortality rate following EVAR compared to OSR (OR = 0.733, P = 0.425) for Chinese patients. In Western patients, the postoperative complication rate of respiratory system and cardiac system was lower in the EVAR group than in the OSR group (OR = 0.270, P < 0.001 and OR = 0.411, P < 0.001, respectively), nevertheless, for Chinese patients, limb ischaemia was more common (OR = 1.539, P = 0.049) in the EVAR group. Whether in Western patients with an eight-year follow-up period or Chinese patients with a maximum four-year follow-up period, there was no significant difference between the EVAR and OSR groups in the all-cause death rate (hazard ratio (HR) = 1.026, P = 0.483 and HR = 1.173, P = 0.247, respectively). Chinese patients were more likely to receive EVAR than OSR and the 30-day mortality was significantly lower for EVAR than for OSR in Western patients but not in Chinese patients. Endovascular repair can be applied to Chinese patients with a reasonable safety margin. Further work is needed to explore the causes of these treatment differences.