Abstract 2884: Elevated Postoperative Cardiac Troponin I Levels Independently Predict Higher Long-Term Morbidity and Mortality Following Off-Pump CABG
Background- Cardiac enzyme elevations after CABG are frequent, but little is known about the long-term outcomes of patients. The aims of the present study were to evaluate the prognostic significance of postoperative cTnI and CK-MB elevations on long-term morbidity and mortality following off-pump CABG.
Methods- Between 1996 and 2004, 1004 consecutive off-pump CABG procedures were performed. Major adverse cardiac events (MACE) were defined as cardiac death or death of unknown cause, myocardial infarction, repeat revascularization and recurring angina. Mean length of follow-up was 4.6 ± 1.9 years (up to 9 years). Follow-up was 100% complete. Time-specific effects were estimated using parametric multiphase hazard regression.
Results- Elevated cTnI (>0.3 ng/mL) and CK-MB (>50 ng/mL) were observed in 166/719 (23%) and 85/1001 (8%) of patients, respectively. Thirty-day mortality was 1.8%. The incidence of perioperative myocardial infarction was 2%. Overall 8-year survival was 71 ± 3% and cardiac survival was 93 ± 1%. Long-term mortality was independently predicted by cTnI (p <.001, respectively; see figure⇓), but not by CK-MB (p >.05). Long-term incidence of MACE was independently predicted by postoperative cTnI (p = 0.02), not by CKMB (p >.05). MACE-free survival at 5 years ranged from 86 ± 3% for the lowest cTnI quartile to 69 ± 4% in the highest (p <.001).
Conclusion- Postoperative levels of cTnI bear significant prognostic value on long-term morbidity and mortality following off-pump CABG. cTnI is a more sensitive marker of long-term outcomes than CK-MB. Patients with mild cTnI elevations after CABG should be closely followed up despite an uneventful postoperative recovery.