Correlation of cardiac troponin I levels (10 folds upper limit of normal) and extent of coronary artery disease in non-ST elevation myocardial infarction

Abstract

Objective: To determine the correlation of cardiac troponin I (cTnI) 10 folds upper limit of normal (ULN) and extent of coronary artery disease (CAD) in Non-ST-elevation myocardial infarction (NSTEMI).

Methods: A cross-sectional study was conducted on 230 consecutive NSTEMI patients admitted in Tabba Heart Institute, Karachi between April to December 2008. cTnI was measured using MEIA method. All patients underwent coronary angiography in the index hospitalization. Stenosis > or = 70% in any of the three major epicardial vessels was considered significant CAD. Extent of CAD was defined as significant single, two or three vessel CAD. Chi-square test was applied to test the association between cTnI levels and CAD extent.

Results: Out of 230 patients, in 111 patients with cTnI levels < or = 10 folds upper limit of normal (ULN), 25 (22.52%) had single vessel, 40 (36%) had two vessel and 34 (30.6%) had three vessel significant CAD, whereas in 119 patients with cTnI levels > 10 folds ULN, 23 (19.3%) had single vessel, 37 (31.1%) had two vessel and 55 (46.2%) had three vessel significant CAD. The results suggest that there was an insignificant association between the cTnI levels and single vessel, two vessel and the overall CAD extent (p = 0.35, p = 0.21 and p= 0.13 respectively), however there was a statistically significant association between the cTnI levels and three vessel CAD (p < 0.04).

Conclusion: Higher cTnI levels are associated with an increased proportion of severe three vessel CAD involvement. Prompt identification and referral of this patient subset to early revascularization strategies would improve clinical outcomes.