Association Between Continuously Recorded ST Changes and Perioperative Myocardial Injury: An Explorative Prospective
Arman Valadkhani1,2, Samuel Bruchfeld3,4,5, Anil Gupta1,2
1From the Function Perioperative Medicine and Intensive Care (PMI) and Heart, Vascular and Neuro Theme, Karolinska University Hospital, Stockholm, Sweden.
Background:
Perioperative myocardial injury (PMI) is associated with a higher mortality after noncardiac surgery. Ischemic symptoms are uncommon postoperatively due to analgesics used perioperatively, necessitating nonsymptomatic surveillance. Although ST-segment deviation indicates myocardial ischemia, its association with PMI remains poorly understood. This study explored the association between continuous perioperative ST-segment monitoring and PMI in patients undergoing intermediate- to high-risk vascular surgery.
Methods:
This was a prospective, single-center cohort study. In addition to standard monitoring, all patients were monitored using a six-lead continuous electrocardiography (ECG) with ST-segment analysis perioperatively. ST events were analyzed according to the fourth universal myocardial infarction definition and as individualized deviations from lead-specific baseline values. The primary outcome was PMI, defined by an increase in high-sensitivity cardiac troponin T measured preoperatively and at 4 to 6, 24, and 48 hours postoperatively. Multivariable Poisson regression was used for primary analysis.
Results:
In total, 498 patients were included, and 46 (9%) incurred PMI. ST-elevation was seen in 89 (18%) and not significantly associated with PMI (adjusted relative risk [RR], 1.75; 95% confidence interval [CI], 0.87-3.53; P = .12), whereas ST-depression was seen in 38 (8%) and showed a significant association with PMI (adjusted RR, 3.85; 95% CI, 1.86-7.94; P < .001). Absolute ST-segment deviation >1 mm from individualized lead baseline was also associated with PMI (RR, 2.03; 95% CI, 1.01-4.06; P = .046). When ST-depression was added to the baseline model, including age and the American Society of Anesthesiologists (ASA) physical status classification system, overall net risk classification improved (NRI, 0.50; 95% CI, 0.16-0.86).
Conclusions:
ST-depression meeting universal myocardial infarction criteria and ST deviations >1 mm from individualized baseline were associated with PMI. Intra- and postoperative ST-segment monitoring may facilitate detection of PMI.
