Clinical Utility of Cardiac Troponin I in the Diagnosis of Acute Coronary Syndrome in Patients With Renal Failure

To analyze sensitivity and specificity of cardiac troponin I (cTnI) in detecting obstructive coronary artery disease in African American population with renal insufficiency presenting with acute coronary syndrome. Retrospective analysis of 108 patients who underwent coronary angiography over a 3-year period in a single institution. A troponin I level of 0.1 ng/mL or higher was considered abnormal troponin I. Renal insufficiency was defined as creatinine of 1.2 mg/dL or higher. Obstructive coronary artery disease (CAD) was defined as luminal diameter reduction of 70% or more (or total occlusion) in at least 1 coronary artery. Patients were divided into group 1 (renal insufficiency without need for hemodialysis, n = 76, mean age = 65) and group 2 (patients requiring hemodialysis, n = 32, mean age = 60). Access Accu TnI method was used to quantitate cTnI where murine monoclonal antibodies specifically bind to the C-terminal end of cTnI. In group 1, 41 (54%) patients had abnormal troponin of whom 37 (90%) had CAD and 4 (10%) had normal angiogram; 35 (46%) patients had normal troponin, of whom 25 (71%) had CAD and 10 (29%) had normal angiogram yielding a sensitivity of 60% and specificity of 71% (P = 0.003; 95% confidence interval). In group 2, 20 (63%) had abnormal troponin of whom 19 (95%) had CAD and 1(5%) had normal angiogram; 12 (38%) had normal troponin of whom 7 (59%) had CAD and 5 (41%) had normal angiogram yielding a sensitivity of 73% and specificity of 83% (P = 0.06; 95% confidence interval). cTnI has a sensitivity of 60% and specificity of 71% in acute coronary syndrome patients with renal insufficiency. In patients on hemodialysis, troponin I has a sensitivity of 73% and specificity of 83% for detection of obstructive CAD.