Value of troponin T as a screening test of cardiac structure and function in chronic kidney disease

Abstract

Background: Cardiovascular disease starts early in the course of chronic kidney disease (CKD) and is the leading cause of death in patients with end-stage renal disease. Since high-sensitivity cardiac troponin T (hs-cTnT) can detect much lower levels of myocardial injury than conventional assays, it may be useful for studying the earliest stages of heart disease in patients with CKD.

Objective: To evaluate the association of circulating hs-cTnT with LV structural and functional abnormalities detected by echocardiography among dialysis dependent and non-dialysis dependent CKD patients.

Methods: This study was conducted on 107 subjects divided into three groups.

Group I consisted of CKD patients on conservative treatment (n=42), Group II: hemodialysis patients (n=42), Group III: control group: age and sex matched healthy volunteers (n=23). All subjects were subjected to clinical examination, biochemical evaluation including estimation of hs-cTnT and Echo-Doppler study of cardiac structure and function.

Results: There was a significant increase in LAV (p<0.01), LVM (p<0.01) in both patient groups compared to the control group. Mitral annular plane systolic excursion (MAPSE) was significantly decreased in both patient groups compared to the control group (p<0.01, p<0.05) and in group I compared to group II (p<0.05) with a significant decrease in S velocity in group I compared to groups II and III (p<0.01). There was a significant decrease in Vp (p<0.01) with a significant increase in AEF (p<0.01) in both patients’ groups compared to the control group and AEF was significantly increased in group II compared to group I (p<0.01). Ea velocity and Ea/Aa decreased significantly (p<0.01) with significant increase in Aa velocity (p<0.05, p<0.01), E/Ea (p<0.01) and E/Vp (p<0.05) in both patient groups compared to the control group. 

There was a significant increase in hs-cTnT levels in both patient groups compared to the control group (P<0.01). We found a positive correlation between hs-cTnT levels and LAV (r=0.291, p<0.03), IVST (r=0.374, p<0.004), PWT (r=0.309, p<0.02), LVM (r=0.282, p<0.03), A wave velocity (r=0.271, p<0.04), E/Ea (r=0.506, p<0.0001), PCWP (r=.507, p< 0.0001) and a negative correlation between hs-cTnT and MAPSE (r=-0.300, p<0.02), S wave velocity (r= -0.259, p<0.05), Ea (r=-626, p<0.0001), Ea/Aa (r=-0.543, p<0.0001). 

Troponin at the cut-off value of >5 ng/L, revealed 100% sensitivity and 95% specificity with areas under curve (AUC) of 0.998 and accuracy of 95.65% (P<0.01) for discrimination of Group I vs control group and 76.2% sensitivity and 95.7% specificity with AUC 0.796 and accuracy 71.84% (P<0.01) for discrimination of group II vs control group. 

Conclusion: Structural and functional cardiac abnormalities are common in CKD patients. Serum hs-cTnT levels increased in CKD patients and was associated with LVH, LAV and some of the echocardiographic parameters of LV systolic and diastolic dysfunction. 

Our research suggests that hs-cTnT levels may be important for early screening of cardiac structure and function in CKD patients to provide evidence for early intervention.