Cardiopulmonary exercise testing in endovascular repair of abdominal aortic aneurysm

Abstract

Cardiopulmonary exercise testing (CPET) has been shown to predict in-hospital and mid-term mortality following elective open abdominal aortic aneurysm (AAA) repair [1] but its role in endovascular repair (EVAR) has not been fully examined. This retrospective study sought to determine the relationship between individual CPET variables, Lee's revised cardiac risk index (RCRI), modified customised probability index (MCPI) and in-hospital mortality in patients undergoing elective EVAR in a single tertiary centre. received patient controlled analgesia postoperatively. The median (range) aortic clamp time was 95 (40-160) min with an operative time of 361 (250-455) min. Twenty patients' tracheas were extubated in theatre and 10 in the ICU. The median (range) postoperative epidural requirement was 1 (0-3) days; time to return to solid diet was 1 (1-5) days and time to mobilisation was 1 (1-4) days; the postoperative hospital stay was 4 (2-98) days. There were three early postoperative complications: one patient had bleeding from a splenic capsule tear; one developed an ischaemic left colon; and one had an anastomotic leak. There were no myocardial infarctions. One patient died after anastomotic leak whilst on dialysis, having developed acute renal failure due to rhabdomyolysis from pressure to the right thigh. Discussion: Laparoscopic aortic surgery requires careful consideration of positioning, pressure point protection and an anaesthetic technique that facilitates both surgical exposure and an accelerated recovery. Despite longer operative and clamp times, early extubation, early feeding and early mobilisation were possible with acceptable morbidity and mortality rates. Epidural requirements were reduced and hospital stay shortened. (Table presented) Methods: One hundred and eighty-five patients underwent EVAR from September 2005 to June 2009, of whom 100 had pre-operative CPET. Pre-operative variables were examined for an association with in-hospital mortality. Univariate analyses included Mann-Whitney U, chi-square, Fisher exact tests, correlation and logistic regression. Significant (p < 0.05) variables were entered into a multiple logistic regression model to identity significant independent predictors for mortality. Results: One hundred patients were studied. There were five deaths (5%), three within 30 days of surgery and two at 33 and 49 days in-hospital. Results are shown in Table 1. Initial ROC curve analysis suggests a cut-off point for VE/VCO 2 of 44, at and above which in-hospital survival may be decreased, though this is not yet of statistical significance (p = 0.08). Discussion: Ventilatory equivalents for CO 2 (VE/VCO 2) and diabetes were identified to be significant independent predictors of mortality in these patients. There is a need for robust pre-operative assessment in patients presenting for EVAR, particularly as many of these patients are deemed high risk for open repair and may not benefit from intervention [2]. Pre-operative CPET data such as VE/VCO 2 are useful in identifying patients at greatest risk of in-hospital mortality.