Troponin I as a prognostic marker of cardiac events in asymptomatic hemodialysis patients using a sensitive troponin I assay

Abstract

Elevated troponin T is known to be a prognostic marker for long-term cardiac events and mortality in asymptomatic end-stage renal disease patients. There are conflicting data in this regard with respect to troponin I (TnI). We recently showed a high incidence of elevated TnI levels in asymptomatic hemodialysis (HD) patients using a new generation sensitive TnI assay. The aim of this pilot study was to explore the prognostic value of TnI, as measured with this new assay, as a marker for outcomes in HD patients over a 2-year follow-up period. Fifty-one asymptomatic HD patients were enrolled, and pre-dialysis TnI levels were checked once monthly over 3 consecutive months. Patients were considered to be in the TnI positive group if TnI level on any of the three draws was ≥0.035 ng/ml. All patients were followed for a period of 2 years. The primary end points were acute coronary syndrome, coronary revascularization, sudden death, or cardiac arrest. The secondary end point was all-cause mortality. Elevated TnI levels were found in 51% (26/51) of patients in our cohort. One TnI positive patient was subsequently lost to follow up. There were 6 cardiac events over 2 years, all of which were in the troponin positive group (6/25 or 24%). The presence of a positive TnI at baseline was significantly associated with future cardiac events (p=0.022). A prior history of coronary artery disease (CAD) was also significantly related to future cardiac events (p=0.010). No patient with negative TnI at baseline developed a cardiac event, while 45.5% of those with both a positive TnI and a history of CAD had an event. Fourteen deaths occurred over 2 years, 8 in TnI positive and 6 in the negative group. All-cause mortality was not associated with elevated TnI levels at baseline. We found a significant association between positive TnI and subsequent cardiac events in asymptomatic HD patients followed for 2 years. TnI levels, as measured with a sensitive assay, may be useful in assessing cardiac risk in asymptomatic HD patients. This needs further confirmation in a larger cohort.

Troponin I Levels in Asymptomatic Hemodialysis Patients

“…All the patients were on maintenance HD 3 times a week with a median dialysis age of 19 months and with a diabetic or vascular ESRD etiology in 57% of cases. Although the prevalence of baseline cTnI elevation that we observed is not grossly different from that obtained in other studies using recent higher sensitive assays, it is slightly lower than that obtained in studies that used the same laboratory assay we used [8,9,10,11]. This discrepancy probably reflects some differences in baseline population characteristics, such as a slightly lower prevalence of diabetes and coronary artery disease and a shorter dialysis vintage in our study.…”

“…Although cTnT levels were more frequently increased and also more tightly associated to poor outcome than cTnI when evaluated using conventional assays [4], the more recently introduced cTnI assays with higher sensitivity led to the detection of cTnI elevated levels in a wider proportion of ESRD patients [8,9,10] and as shown in the systematic reviews and meta-analyses by Michos et al [12] and Stacy et al [13], to the definitive recognition that persistently elevated cTnI levels are significantly associated with a worse prognosis in patients with ESRD.…”

“…In particular, persistently elevated cTn levels are frequently found in patients with end-stage renal disease (ESRD) in the absence of clinically evident cardiac disease [3]. As a confirmation of this concept, abnormal levels of cTnT have been observed in 29-99% of patients [4,5,6,7], while cTnI has been found elevated in 5-18% of patients, using older-generation assays, and in 15-51% of patients with new-generation higher sensitivity assays [4,8,9,10,11]. While it has been demonstrated that baseline elevated cTn levels in ESRD patients are associated with an adverse long-term outcome [12,13], this persistent elevation may reduce the diagnostic accuracy of cTn assay, making the diagnosis of AMI particularly challenging in this patients population [13,14].…”

Serial versus single troponin measurements for the prediction of cardiovascular events and mortality in stable chronic haemodialysis patients

“…Troponin has now been established to be a useful biomarker to identify the HD patients with the highest cardiovascular risk, even if the management of these patients has not yet been elucidated . Long‐term outcomes have already been evaluated in patients having at least one elevated troponin value over three serial monthly measurements . Although that cohort included only 51 patients and the number of events was small, the MACE rate (but not all‐cause mortality) was associated with elevated baseline troponin I values.…”

Before the Jury Is out on Cinacalcet’s Cardiovascular Effects in Hemodialysis Patients: Is Troponin a Missing Link?

“…Though several cardiac peptides are available, troponin I appears more specifically for myocardial ischemia [4]- [7] and even serves as a prognostic indicators in dialysis patients [8]. It would hence be plausible that following troponin I trends may serve as possible markers of cinacalcet treatment effect on cardiac risk in these patients.…”