Hayeshi, et al studied the utility of using cardiac troponin t as a tool for predicting asymptomatic coronary artery stenosis in CKD patients on renal replacement therapy. The primary finding was that cardiac troponin t was a more potent independent predictor of asymptomatic multivessel coronary artery disease in late stage CKD patients. This raises an important point and makes us wonder will we be using troponin t as a screening tool for asymptomatic coronary artery disase in the future? Further studies are needed to help us with this.
First we need to understand the different troponins in the picture.
Troponin is a component of thin filaments and is the protein to which calcium binds to accomplish this regulation. Troponin has three subunits, TnC, TnI, and TnT.
- Troponin C binds to calcium ions to produce a conformational change in TnI
- Troponin T binds to tropomyosin, interlocking them to form a troponin-tropomyosin complex
- Troponin I binds to actin in thin myofilaments to hold the troponin-tropomyosin complex in place.
Some centers use Tropnin I and some T, both are very sensitive and specific for cardiac events.
The question is which one is better in CKD patients.
Another study by Fehr et al in Clinical Nephrology showed that for diagnosis of ACS in HD patients, a combination of cTnT and cTnI may be used, since the former has higher sensitivity and the latter higher specificity. A higher threshold value for cTnT in HD patients could further increase its diagnostic accuracy.
Interesting the differences in the studies, one with CKD and other with ESRD.