Predischarge oxygen uptake efficiency slope has short and long-term value in the prognosis of patients after acute myocardial infarction

Abstract

Background: Patients who survive an acute myocardial infarction (AMI) have a higher risk of having a major cardiovascular event (MACE). Cardiopulmonary exercise testing (CPET) could develop prognostic stratification and prescribing exercise prescription. Patients after AMI frequently terminate CPET early with submaximal testing results. We aimed to look at the characteristics of patients’ predischarge CPET variables after AMI intervention and find potential CPET variables with prognostic value. Methods: Between July 2012 and August 2017, we recruited patients who survived first AMI after primary percutaneous coronary intervention and received predischarge CPET retrospectively in a tertiary medical center of Taiwan. Patients were followed-up on a MACE or administrative censoring occurred (up to 5 years). To identify significant predictors of a MACE, a Cox regression model was used. Results: 113 patients (103 men and 10 women) were studied, with an average age of 58.32 ± 12.49. MACE over three months, two-years, and five-years was 17.70%, 53.10%, and 62.83%, respectively. The oxygen uptake efficiency slope during the whole during of CPET (OUES 100) divided by body surface area (OUES 100/BSA) was found to be a significant event predictor for MACE at three-month, two and five-years. Cox regression analysis revealed that those with OUES 100/BSA<0.722 (p = 0.004), OUES 100/BSA < 0.859 (p = 0.002), and OUES 100/BSA < 0.829 (p = 0.002) had a 7.14-fold, 3.47-fold, and 2.72-fold increased risk of three-month, two-year, and five-year MACE, respectively. Conclusion: It is critical to identify a submaximal predictor during CPET for patients who survive AMI. Our findings suggested that OUES could be a significant prognostic indicator in patients after first AMI in both the short and long term.