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INTRODUCTION: The ideal approach for cardiac risk stratification in patients undergoing elective endovascular aortic aneurysm repair (EVAR) remains unresolved. Multiple algorithms are utilized to evaluate patients with significant variability amongst institutions and cardiac stress testing remains a widely used modality. Recent ACC/AHA guidelines suggest clinical risk factors can identify patients at highest risk for adverse events. We compared the clinical efficacy and cost savings of risk factor assessment utilizing the revised cardiac risk index (RCRI) versus cardiac stress testing in predicting peri-operative cardiac complications after EVAR.
METHODS: A single center, retrospective study was conducted to identify patients undergoing EVAR between 2009 and 2011. Two-hundred forty-eight patients were identified of which 42 were excluded due to emergent repair. 206 patients were included in the analysis. The pre-operative assessment was identified and a cost analysis was performed based on CMS reimbursement rates for our geographic area. The RCRI was calculated for each patient and used to stratify them according to predicted risk for a peri-operative cardiac event. 30-day event rates for death or symptomatic cardiac events were calculated.
RESULTS: Of the 206 patients, complete records for pre-operative evaluations were available for 197 patients. Of those, 168 patients (85%) underwent cardiac stress testing of which 26 patients (13%) were positive resulting in further testing. Twenty patients with a positive stress test underwent cardiac catheterization; 3 underwent percutaneous coronary intervention (PCI) and 1 underwent coronary bypass grafting. There were no peri-operative deaths. Six (2.9%) patients had clinical symptoms prompting measurement of serum troponin levels which were elevated. In patients with a negative stress test, five MIs occurred (3%) vs. 1 MI in patients with a positive stress test (3.8%) (p = 0.86). When stratified by the RCRI, patients with fewer than 3 risk factors had an MI rate of 2.5% vs. 16.7% in patients with 3 or more factors (p = 0.04). Including the resultant procedures, the per-patient cost for routine pre-operative was $3500.
CONCLUSIONS: Routine pre-operative cardiac stress testing for patients undergoing elective endovascular aneurysm repair is unwarranted. It results in additional invasive testing and therapy with a concomitant cost increase. The RCRI is a reliable tool for risk stratification and guiding pre-operative work-up in patients scheduled for elective endovascular aneurysm repair. The RCRI should replace qualitative physician determination of fitness for EVAR. This represents a potential area for improved resource utilization strategies.

Stress Test and Perioperative MI by Risk Score

RCRI Risk Score	Stress Test Yes N(%)	Stress Test No N(%)	MI Yes N(%)	MI No N(%)
Less than 3	163(85)	28(15)	5(2.5)	195(97.5)
3 or more	5(83)	1(17)	1(17)	5(83)