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Importance of long-duration postoperative ST-segment depression in cardiac morbidity after vascular surgery
G Landesberg1, M H Luria, S Cotev
1Department of Anesthesiology and Critical Care Medicine, Hebrew University-Hadassah Medical Center, Jerusalem, Israel.
Insights
Major vascular surgery patients often experience cardiac ischemia. Long-duration postoperative ischemia, indicated by ST-segment depression, significantly predicts cardiac complications and myocardial injury.
Area of Science:
- Cardiology
- Vascular Surgery
Background:
- Major vascular surgery carries a high risk of cardiac ischemic complications.
- Continuous perioperative electrocardiographic monitoring is crucial for assessing myocardial ischemia.
Observation:
- 151 patients undergoing major vascular surgery were monitored for perioperative myocardial ischemia.
- 342 ischemic episodes (ST-segment depression) were recorded, with 48% occurring postoperatively.
- Postoperative ischemic episodes were significantly longer than preoperative or intraoperative episodes.
Findings:
- 13% of patients experienced postoperative cardiac events, including myocardial infarctions, unstable angina, and congestive heart failure.
- Both Detsky's cardiac risk index and prolonged preoperative ischemia predicted complications.
- Long-duration postoperative ischemia (>2 hours) was the strongest predictor of cardiac morbidity (OR 21.7, p=0.001).
- Prolonged ST-segment depression preceded most postoperative cardiac events, with non-Q-wave infarctions being common.
Implications:
- Long-duration subendocardial ischemia, not acute coronary occlusion, appears to be the primary cause of postoperative myocardial injury.
- These findings highlight the importance of monitoring and managing prolonged postoperative ischemia to reduce cardiac morbidity after vascular surgery.
Abstract:
Major vascular surgery is associated with a high incidence of cardiac ischaemic complications. By means of continuous perioperative electrocardiographic recording, we studied 151 consecutive patients undergoing major vascular surgery to find out the characteristics of any myocardial ischaemia and the relation to outcome. 13 (8.6%) patients had postoperative cardiac events (6 myocardial infarctions, 2 unstable angina, and 5 congestive heart failure). There were 342 perioperative ischaemic episodes shown by ST-segment depression; 164 (48%) occurred postoperatively. Postoperative ischaemic episodes were significantly longer than episodes before or during operations (3.2 vs 1.7 and 1.5 min per h monitored, respectively, p < 0.001). Both Detsky's cardiac risk index and long-duration (> 2 h) preoperative ischaemia were predictive of postoperative cardiac complications (odds ratios in univariate analysis 3.3, p = 0.03, and 7.2, p = 0.009, respectively). However, long-duration (> 2 h) postoperative ischaemia was the only factor significantly associated with cardiac morbidity in multivariate logistic regression analysis (odds ratio 21.7, p = 0.001). Long-duration ST-segment depression preceded most (84.6%) postoperative cardiac events, including myocardial infarctions, and no cardiac event was preceded by ST-segment elevation. 5 of the 6 postoperative myocardial infarctions were non-Q-wave infarctions. We conclude that long-duration subendocardial ischaemia, rather than acute coronary artery occlusion, may bring about postoperative myocardial injury and complications.