PRE-OPerative ECHOcardiograhy for prevention of cardiovascular events after non-cardiac surgery in intermediate- and high-risk patients: protocol for a low-interventional, mixed-cohort prospective study design (PREOP-ECHO)

Background: Cardiac evaluation using transthoracic echocardiography before noncardiac surgery is common in real-world practice. However, evidence supporting preoperative echocardiography is lacking. This study aims to evaluate the additional benefit of preoperative echocardiography in predicting postoperative cardiovascular events (CVE) in noncardiac surgery. Methods: This study is designed as a multicenter, prospective study to assess the utility of preoperative echocardiography in patients undergoing intermediate- or high-risk noncardiac surgery. This trial comprises two studies: (1) a randomized controlled trial (RCT) for patients undergoing intermediate-risk surgery with fewer than three clinical risk factors from the revised cardiac risk index (intermediate-risk group) and (2) a prospective cohort study for patients undergoing intermediate-risk surgery with three or more clinical risk factors, or who undergo high-risk surgery regardless of the number of clinical risk factors (high-risk group). We hypothesize that the use of preoperative echocardiography will reduce postoperative CVEs in patients undergoing intermediate- to high-risk surgery through discovery of and further intervention for unexpected cardiac abnormalities before elective surgery. A total of 2330 and 2184 patients will be enrolled in the two studies. The primary endpoint is a composite of all-cause death; aborted sudden cardiac arrest; type I acute myocardial infarction; clinically diagnosed unstable angina; stress-induced cardiomyopathy; lethal arrhythmia, such as sustained ventricular tachycardia or ventricular fibrillation; and/or newly diagnosed or acutely decompensated heart failure within 30 days after surgery. Discussion: This study will be the first large-scale prospective study examining the benefit of preoperative echocardiography in predicting postoperative CVE. The PREOP-ECHO trial will help doctors identify patients at risk of postoperative CVE using echocardiography and thereby reduce postoperative CVEs. Trial registration: The Clinical Research Information Service KCT0006279 for RCT and KCT0006280 for prospective cohort study. Registered on June 21, 2021.