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

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.