COMPARISON OF TROPONIN I WITH CK-MB AND ECG FOR PREDICTING CLINICALLY SIGNIFICANT MYOCARDIAL INJURY AFTER CORONARY ARTERY BYPASS GRAFTING

Abstract

Objective: To compare quantitative values of cTnI with CKMB and ECG according to Task Force’s definition in detecting/predicting perioperative myocardial infarction (PMI) after coronary artery bypass grafting.

Study Design: Comparative cross sectional study.

Place and Duration of Study: Armed Forces Institute of Cardiology and National Institute of Heart Diseases from February, 2018 to August, 2018.

Materials and Methods: A comparative cross sectional study was conducted on 122 patients, who underwent elective coronary artery bypass grafting (CABG) during specified period. Ejection fraction above 20% and cardiopulmonary bypass with single aortic cross-clamp technique were inclusive factors too while redo CABG, low HCT, recent MI and concomitant valve procedures were excluded from the study. Sampled with consecutive non probability technique and patients assessed on AHA task force perioperative MI criteria. cTnI compared with CK-MB and ECG in predicting clinically significant PMI, morbidity/mortality and length of hospital stay (HLOS).

Results: Among 122 patients, 64% were males and 36% females. Mean age among participants was 50.75 years with standard deviation of 7.49. A therapeutic elevation of cTnI was observed in 11 (9%) as compared to CKMB elevations in 24 (19.7%). A total mortality was 13 (10.6%) wherein 6 (4.9%) patients had elevated cTnI as compared to elevated CKMB in 12 (9.8%) patients. HLOS averaged at 6 days (>60%) with 8 (6.4%) patients had >6 days stay in significant CKMB group as compared to 6 (4.8%) patients for elevated cTnI. Perioperatively 10 (8%) patients had atrial fibrillation in elevated CKMB group as compared to 4 (3.3%) in elevated cTnI group. Frequency of IABP and CRRT was 11 (8.8%) and 2 (1.6%) in elevated cTnI group as compared to 24 (19.2%) and 6 (4.8%) in elevated CKMB group respectively.

Conclusion: For Pakistani perspective cTnI and CKMB along ECG carry equivocal statistical significance in predicting PMI. However CKMB carries added advantage of detecting postoperative renal dysfunction. Further studies are essential to clarify this important association.