Prolonged ST depression-type ischemia was significantly longer in patients who developed postoperative myocardial infarction compared to those without infarction (226 vs 38 minutes; p=0.0000).
Cohort (n=185)
Prolonged, ST depression-type silent ischemia is strongly associated with the development of postoperative myocardial infarction following vascular surgery.
Absolute Event Rate: 226% vs 38%
p-value: p=0.0000
OBJECTIVES: The goal of this study was to investigate the nature of the association between silent ischemia and postoperative myocardial infarction (PMI). BACKGROUND: Silent ischemia predicts cardiac morbidity and mortality in both ambulatory and postoperative patients. Whether silent stress-induced ischemia is merely a marker of extensive coronary artery disease or has a closer association with infarction has not been determined. METHODS: In 185 consecutive patients undergoing vascular surgery, we correlated ischemia duration, as detected on a continuous 12-lead ST-trend monitoring during the period 48 h to 72 h after surgery, with cardiac troponin-I (cTn-I) measured in the first three postoperative days and with postoperative cardiac outcome. Postoperative myocardial infarction was defined as cTn-I >3.1 ng/ml accompanied by either typical symptoms or new ischemic electrocardiogram (ECG) findings. RESULTS: During 11,132 patient-hours of monitoring, 38 patients (20.5%) had 66 transient ischemic events, all but one denoted by ST-segment depression. Twelve patients (6.5%) sustained PMI; one of those patients died. All infarctions were non-Q-wave and were detected by a rise in cTn-I during or immediately after prolonged, ST depression-type ischemia. The average duration ofischemia in patients with PMI was 226+/-164 min (range: 29 to 625), compared with 38+/-26 min (p = 0.0000) in 26 patients with ischemia but not infarction. Peak cTn-I strongly correlated with the longest, as well as cumulative, ischemia duration (r = 0.83 and r = 0.78, respectively). Ischemic ECG changes were completely reversible in all but one patient who had persistent new T wave inversion. All ischemic events culminating in PMI were preceded by an increase in heart rate (delta heart rate = 32+/-15 beats/min), and most (67%) of them began at the end of surgery and emergence from anesthesia. CONCLUSIONS: Prolonged, ST depression-type ischemia progresses to MI and is strongly associated with the majority of cardiac complications after vascular surgery.
Landesberg et al. (2001) conducted a cohort in Vascular surgery (n=185). Prolonged ST depression-type ischemia vs. Transient ischemia without infarction was evaluated on Average duration of ischemia in patients with versus without postoperative myocardial infarction (p=0.0000). Prolonged ST depression-type ischemia was significantly longer in patients who developed postoperative myocardial infarction compared to those without infarction (226 vs 38 minutes; p=0.0000).