Cardiac Troponin T and Cardiac Troponin I Levels in End Stage Renal Disease Patients Undergoing Hemodialysis : as Markers of Myocardial Injury

Yoon, Hyeok Jin; Lee, Sang Bong; Kim, Yang Wook; Kim, Yeong Hoon; Chung, Woo Yeong; Kim, Myeong You; Lee, Jeong Nyeo

Abstract

BACKGROUND: The main cause of death in maintenance hemodialyzed patients is cardiovascular event. Serum cardiac troponin T(cTnT) and I(cTnI) are increased in the serum of patients with chronic renal failure.
METHODS
We studied the incidence of increased serum cTnT and cTnI, the differences of their positivity, and the myocardial injury and cardiovascular risk factors in 56 maintenance hemodialyzed patients (30 males, 26 females). We investigated the patients about smoking, diabetes, hypertension and anginal pain. Blood was obtained from the patients immediately before hemodialysis. Samples were analyzed for myoglobin, CPK, LDH, total cholesterol, hemoglobin, PTH, cTnT and cTnI. Also, we evaluated the duration and adequacy(Kt/V(urea)) of dialysis and ECG. cTnT was measured by ECLIA(reference value RESULTS
The mean age was 47 years(range from 15 to 73) and the mean dialysis duration was 38.7 months(range from 2 to 156). Myocardial ischemia was observed in 57.1%(32/56) of the patients. cTnT level above 0.1 ng/mL and cTnI level above 0.5 ng/ mL was observed in 32%(18/56) and 14%(8/56) of patients respectively. cTnT revealed significantly higher positive rate in the patients with myocardial ischemia than the patients without myocardial ischemia(37.5% vs 4.2%)(p=0.001). cTnI revealed no difference in positive rate between the patients with and without myocardial ischemia(18.8% vs 8.3%). The sensitivity and specificity of cTnT to myocardial ischemia were higher than those of cTnI(sensitivity 37.5% vs 18.8%, specificity 95.8% vs 91.6%). The patients with myocardial ischemia revealed hypertension, age over 40, Kt/V(urea) under 1.4, and increased LDH, CPK, myoglobin, PTH levels with significantly higher frequency comparing to the patients without myocardial ischemia(p < 0.05). cTnT levels correlated to LDH, myoglobin, age, PTH levels and Kt/V(urea)(r=0.46, p=0.0003; r=0.29, p=0.0282; r=0.42, p=0.0014; r=-0.49, p=0.0001; r=-0.29, p=0.0282). cTnI levels correlated to age(r=0.47, p=0.0003) only.
CONCLUSION
cTnT is a more sensitive and equally specific marker of myocardial ischemia than cTnI in patients undergoing maintenance hemodialysis. Also we may suggest that myocardial injury and increased cTnT levels are related to inadequate dialysis, secondary hyperparathyroidism and other cardiovascular risk factors in maintenance hemodialyzed patients.