Cardiac troponin I (cTnI) is a highly sensitive and specific marker for postoperative prediction of patients outcome after coronary artery bypass surgery (CABG). Whether preoperatively elevated cTnI levels similarly predict outcome in patients scheduled for elective CABG is currently unknown.
We therefore investigated a possible correlation between preoperative cTnI levels and perioperative adverse events and in-hospital mortality after CABG. Between January 2000 and January 2004 cTnI was measured within 24 hours before surgery in 1405 out of 3124 consecutive elective CABG patients. Out of these patients, 1178 were assigned with a preoperative cTnI level below 0.1 ng/mL to group 1, 163 patients with a cTnI level between 0.11-1.5 ng/mL to group 2, and 64 patients with a cTnI level above 1.5 ng/mL to group 3. CTnI levels, electrocardiograms, clinical data, adverse events and in-hospital mortality were recorded prospectively. Patients with myocardial infarction less than seven days ago were excluded from the study.
Perioperative myocardial infarction (PMI) occurred in 69/1178 patients (5.9%) in group 1, 14/163 patients (8.6%; odds ratio (OR) 1.5, 95% confidence interval (CI):0.8-2.8) in group 2, and 11/64 patients (17.2%;OR 3.3,95%CI:1.6-7.0) in group 3 (overall:P<0.001, Cochran-Armitage trend test). Low cardiac output with subsequent IABP-support occurred in 19/1178 patients (1.6%), 9/163 (5.5%;OR 3.6,95%CI:1.5-8.5), and 7/64 patients (10.9%;OR 7.5,95%CI:2.7-19.8) overall: P<0.001, group 1 vs. group 2: P<0.002), respectively. In-hospital mortality was 1.7% in group 1 and 3.1% in group 2, but 6.3% (OR 3.9,95%CI:1.1-12.5) in group 3 (overall: P<0.001, group 1 vs. group 2: P=NS). Intensive care and hospital stay was significantly longer in group 3 compared to groups 1 and 2. Logistic regression analysis confirm the statistically significant relationship between cTnI and PMI, IABP-support and in-hospital mortality, respectively (P<0.001).
Risk stratification by measurement of cTnI levels within 24 hours before elective CABG clearly identifies a subgroup of patients with increased risk for postoperative adverse outcome and in-hospital mortality.
Clinicians should be prepared in postoperative treatment of those patients. Waiting in some may be warranted.
M. Thielmann, None.