Cardiopulmonary exercise testing and elective open abdominal aortic aneurysm surgery over a 6-year period in a UK teaching hospital

Abstract

Introduction A reduced oxygen uptake at anaerobic threshold (AT) and an elevated ventilatory equivalent for carbon dioxide (VE/VCO2) have been shown to be predictors of outcome after major surgery [1]. We report the demographic and outcome data of patients undergoing elective open abdominal aortic aneurysm (AAA) surgery who underwent cardiopulmonary exercise testing (CPET) testing within our unit and examine the relationship between age, AT and VE/VCO2 on survival outcomes. Methods A retrospective observational analysis of our unit's CPET Excel database was conducted to identify patients who underwent CPET testing for elective open AAA repair over a 6-year period. Demographic data and survival at 30 days, 90 days and 1 year were extracted. Logistic regression analysis was undertaken using STATA statistical software to determine if age, AT or VE/VCO2 were predictors of survival at 30 days, 90 days or 1 year. Results CPET was performed in 259 patients who subsequently underwent an elective open AAA repair. Outcome data were available for 185 patients from a potential 222 in whom 1-year follow-up was available (83%). Baseline demographics included AT 10.9 ml/kg/minute in 61% of patients with respective median ages in these groups being 73 and 72. Regression analysis demonstrated that AT was the only predictor of survival at 30 days, 90 days and 1 year. Age and AT remained independent predictors of survival at 90 days and 1 year following multivariate analysis. Of note, 87 patients underwent elective endovascular aneurysm repair and CPET, median age 76, during the period analysed. In particular, 26.4% were older than 80 years old, versus 14.7% in the AAA group. See Figure 1. Conclusion Our data support existing evidence that AT can be used as a predictor of survival in open elective AAA surgery. In addition, age at (Figure presented) CPET also predicted 90-day and 1-year survival; however, VE/VCO2 was not a predictor of survival in this cohort.