Early and Delayed Myocardial Infarction after Abdominal Aortic Surgery

Background: Although postoperative myocardial infarction (PMI) after vascular surgery has been described to be associated with prolonged ischemia, its exact pathophysiology remains unclear.

Methods: The authors used intense cardiac troponin I (cTnI) surveillance after abdominal aortic surgery in 1,136 consecutive patients to better evaluate the incidence and timing of PMI (cTnI >= 1.5 ng/ml) or myocardial damage (abnormal cTnI < 1.5 ng/ml).

Results: Abnormal cTnI concentrations was noted in 163 patients (14%), of which 106 (9%) had myocardial damage and 57 (5%) had PMI. In 34 patients (3%), PMI was preceded by a prolonged (> 24 h) period of increased cTnI (delayed PMI), and in 21 patients (2%), the increase in cTnI lasted less than 24 h (early PMI). The mean times from end of surgery to PMI were 37 +/- 22 and 74 +/- 39 h in the early PMI and delayed PMI groups, respectively (P < 0.001). The mean time between the first abnormal cTnI and PMI in the delayed PMI group was 54 +/- 35 h, during which the cTnI profiles of the myocardial damage and delayed PMI groups were identical. In-hospital mortality rates were 24, 21, 7, and 3% for the early PMI, delayed PMI, myocardial damage, and normal groups, respectively.