Correlation of location of acute myocardial infarct after noncardiac vascular surgery with preoperative dobutamine echocardiographic findings

Abstract

T aim of this study was to assess the usefulness of preoperative dobutamine stress echocardiography (DSE) for the identification of culprit coronary lesions in patients who died within 30 days of major vascular surgery and underwent autopsy. • • • The records of all 1,065 patients who underwent elective major vascular surgery (abdominal aortic aneurysm resection, aortofemoral bypass, and infrainguinal arterial reconstruction) between 1989 and 2000 at the Eramus Medical Centre, Rotterdam, The Netherlands, were screened. Patients were included in the study if they had undergone preoperative DSE, died within 30 days of elective major vascular surgery, and had available autopsy results. We excluded any patients who underwent myocardial revascularization subsequent to DSE but before vascular surgery. A presumptive diagnosis of perioperative acute myocardial infarction (AMI) was made in patients with a serum creatine kinase-MB fraction of 10%, and new electrocardiographic Q waves lasting 0.03 second. DSE was performed as previously described. The left ventricle was divided into 16 segments, and wall motion was scored on a 5-point scale (1 normal, 2 mild hypokinesia, 3 severe hypokinesia, 4 akinesia, and 5 dyskinesia). The result was considered positive if wall motion in any segment deteriorated by 1 grade during testing new wall motion abnormalities (NWMA). Ischemic segments were grouped into 3 coronary territories: left anterior descending, left circumflex, and right coronary arteries. A cardiac pathologist (MK), unaware of the DSE results, reviewed all postmortem reports and the heart specimen sections and determined the presence and location of recent AMI. Coronary arteries were cut at 5-mm intervals. AMIs were subsequently grouped into the appropriate coronary territories, whether a coronary thrombus was present or not. Established myocardial scars were not included, but recent ischemia adjacent to a scar was. Continuous data are presented as mean value (range); dichotomous data are presented as percentages. Sensitivity and specificity figures, global and region specific, are determined for DSE-induced ischemia to predict AMI as assessed by autopsy. No inferential statistics were obtained. Thirty-two patients met our inclusion criteria of preoperative DSE, elective major vascular surgery, perioperative death, and available autopsy results. The clinical characteristics, DSE results, and autopsy findings of these patients are listed in Table 1. Most patients were elderly, and the clinically suspected cause of death was cardiac in 53%. DSE was positive (i.e., stress-induced NWMA) in 16 patients (50%). In 7 of these patients, ischemia was induced in 1 coronary territory. Stress-induced NWMA was apparent in the left anterior descending (n 11 [69%]), left circumflex (n 9 [56%]), and right coronary artery (6 [38%]) territories. Twenty-one patients (66%) showed evidence of myocardial infarction at autopsy. In 9 of these patients (43%), infarction involved 1 coronary territory. Infarction was localized to the left anterior descending (n 14 [66%]), left circumflex (n 12 [57%]), and right coronary artery (n 7 [33%]) territories. Surgery was performed 41 days (range 5 to 81) after DSE. Autopsy was performed within 2 days after patients’ death. In all of the 16 patients with inducible ischemia during DSE, the clinically suspected cause of death was cardiac and all showed AMI at autopsy. However, 5 patients without preoperative stress-induced ischemia also exhibited evidence of recent myocardial ischemia at autopsy. Of these 5 patients, the suspected cause of death was stroke in 2, sepsis in 1, massive bleeding in 1, and cardiac in 1. The sensitivity and specificity DSE for prediction of a perioperative AMI in this subset of patients were 76% (16 of 21 patients) and 100% (11 of 11 patients), respectively. In 81% of these patients (13 of 16), AMI was located in a coronary artery territory that also exhibited stress-induced ischemia on DSE. However, in 9 of 16 patients (56%), pathologic evidence of infarction was apparent in a coronary artery territory that did not exhibit NWMA during DSE. The sensitivity and specificity of DSE for prediction of infarction in a specific territory were 44% (7 of 16 patients) and 69% (11 of 16 patients), respectively. • • • This study showed that patients who died after major noncardiac vascular surgery frequently had significant coronary pathology. Preoperative DSE is useful in identifying these patients. Inducible ischemia on DSE was noted in 16 of 32 patients and all 16 of these patients had perioperative AMI. Only 5 patients with From the Thoraxcentre and Department of Pathology, Erasmus Medical Centre, Rotterdam, The Netherlands; and The University of Manitoba, Winnipeg, Manitoba, Canada. Dr. Poldermans’ address is: Thoraxcentre, Room H921, Erasmus University, Rotterdam, The Netherlands. E-mail: poldermans@hlkd.azr.nl. Manuscript received May 29, 2001; revised manuscript received and accepted August 24, 2001.