Troponin I Testing in Dialysis Patients Presenting to the Emergency Room: Does Troponin I Predict the 30-Day Outcome?

Abstract

Background: Troponins are often measured in acutely ill chronic dialysis patients admitted to the emergency room, irrespective of their clinical presentation. The significance of an elevated troponin level in this setting is unclear. Methods: We identified all chronic dialysis patients presenting over 1 year to a tertiary care hospital emergency room who also had at least one cardiac troponin I (cTnI) level determination. We evaluated presenting complaints, risk factors for cardiac disease, cTnI levels, and major cardiac events (MCE; occurrence of cardiovascular death, myocardial infarction, de novo heart failure, or coronary revascularization) within 30 days by chart review in 149 patients (79 on hemodialysis, 70 on peritoneal dialysis). Results: Chest pain was documented in only 29% of the patients. Twenty-two patients (15%) experienced an MCE. The incidence of an MCE was the same in patients with and without chest pain. A cTnI level >0.1 ng/l was a significant predictor of an MCE (odds ratio 15.2, 95% confidence interval CI 5.26, 43.6). The likelihood ratios for MCEs were 0.32 (CI 0.16, 0.63) for a cTnI level <0.1 ng/l, 0.72 (CI 0.09, 5.5) for cTnI concentrations 0.1–0.3 ng/l, 7.8 (CI 4.2, 15) for a cTnI level >0.3, and 11.7 (CI 4.4, 31) for a cTnI concentration >2.0 ng/l. Conclusion: In acutely ill chronic dialysis patients presenting to a hospital emergency room, an elevated cTnI level indicates an increased 30-day cardiac risk, regardless of their clinical presentation.

Comportamiento y valor pronóstico de la troponina I cardiaca en suero en pacientes con enfermedad renal final sometidos a hemodiálisis de largo plazo. Analisis de resultados quinquenales

“…First, raised cTnI, as defined by the reference limit for normal subjects, was associated with an eight-fold greater risk of death. These findings are consistent with previous studies that associate high concentrations of cTnI with a greater risk of mortality and suggest that the relative risk of death varies in accordance with the cut-off point used in each study (1)(2)(3)15,18). Second, the difference in cTnI levels between patients having spent longer and shorter times on dialysis permits consideration of the possibility that haemodialysis itself could induce myocardial ischaemia and a minor degree of troponin I release in patients undergoing haemodialysis treatment.…”

“…Patients with chronic renal failure (CRF) are at greater risk of silent ischaemia and atypical clinical presentation during an acute coronary syndrome. Angina is often absent in patients who suffer from both ESRD and coronary artery disease, occurring in only 17% of cases (2).…”

“…However, in patients receiving maintenance dialysis, the clinical symptoms of cardiac damage are difficult to diagnose and may be misleading. In addition, the traditional cardiac markers, such as creatine kinase (CK), creatine kinase muscle-brain fraction (CK-MB) and myoglobin, have been found to be deceptively high in patients using dialysis (1)(2)(3).…”

“…Furthermore, although recent studies demonstrate that serum or plasma cTnI is an important predictor of longterm, all-cause mortality and cardiovascular mortality in patients with ESRD, and that high concentrations of cTnI are associated with increased risk of coronary artery disease in this population (1)(2)(3), other studies conclude that cTnI has little predictive value in renal insufficiency and they do not identify it as an independent risk factor (8,9). Owing to the uncertainty about the usefulness of cTnI in ESRD, the aim of present study was to evaluate the behaviour and prognostic value of cTnI in a population of chronic haemodialysis patients.…”

Understanding cardiac biomarkers in end‐stage kidney disease: Frequently asked questions and the promise of clinical application

“…Troponin testing was requested for dialysis patients in the emergency department for a variety of symptoms including chest pain, dyspnoea, abdominal pain and others 74 . Regardless of the symptoms, an elevated cTnI predicted major cardiac events.…”