Comparison of elective infrarenal aneurysm surgery with open and endovascular technique, respectively, for subclinical ischemic myocardial injury detectable with troponin T and/or 3-channel Holter ECG with ST analysis

Background: Traditional open surgery for abdominal aortic aneurysm (AAA) is burdened with complication risk from several organ systems, and also mortality figures of 3.5 - 5.5%. Over 50% of early mortality can be attributed to cardiovascular complications. Myocardial infarction is the dominant organ-specific cause of both early and late mortality in patients operated on for AAA. Endovascular surgery (EndoVascular Aortic Repair, EVAR) was developed during the 90's as an alternative method that is considered less invasive and more well-tolerated from a cardiovascular perspective.

Troponin T is a very sensitive and specific marker that predicts mortality in patients with acute symptoms of unstable angina and/or heart attack. Previous studies have also shown a high incidence of elevated troponin levels in patients who underwent major surgical procedures, especially vascular surgery, even in the absence of corresponding clinical or ECG-related symptoms of cardiac muscle injury. Several studies have also demonstrated that elevated troponin levels after surgery predict increased morbidity and mortality both short-term and long-term.

Objective: To prospectively compare elective open and endovascular surgery of AAA with respect to myocardial injury detectable with troponin T. Furthermore, to compare open and endovascular AAA surgery for the total number of periods of oxygen deficiency in cardiac muscle during and at early stages after surgery using a special ECG method (48-hour 3-channel Holter ECG with ST analysis).

Main aim of the study: To assess whether EVAR induce less myocardial injury compared with open repair for AAA.

Significance: Myocardial infarction is the predominant cause of mortality in open surgical procedure for AAA. In several previous studies, troponin T rise has been associated with impaired both short-term and long-term prognosis in elderly patients undergoing major elective surgery. This study may provide information on whether the endovascular technique provides a reduction in myocardial injury, measured as elevated troponin T or myocardial ischemia with 3-channel Holter ECG. In this way, our study can provide improved decision support in the choice of the most appropriate treatment method in the individual case.

Inclusion Criteria:

• Accepted for AAA surgery of either one of the operative techniques

Exclusion Criteria:

• High anesthesiological risk
• Preoperative cardiac condition with EF < 25 or ischemic signs on preoperative evaluation
• Severe renal insufficiency with s-creatinine >200

Consecutive individuals accepted for either open or endovascular aortic repair in two Swedish hospitals