Cardiac high-sensitivity troponin T measurement: a layer of complexity in managing haemodialysis patients.

AIM: To determine: (i) the proportion of stable asymptomatic haemodialysis patients with elevated troponin; (ii) stability of troponin values after dialysis and over a 2-week interval; and (iii) whether high-sensitivity troponin T (hsTnT) was associated with higher prevalence of cardiovascular risk factors or cardiovascular disease in these patients. METHODS: We measured hsTnT and the fourth generation troponin I before and after dialysis in 103 stable in-centre haemodialysis patients without ischaemic symptoms. Patients were divided into quartiles to test for associations with established cardiovascular risk factors or disease. RESULTS: hsTnT was above the 99th percentile for the general population in 99% of haemodialysis patients compared with only 13% elevation for the troponin I assay (P < 0.001). Median pre-dialysis hsTnT concentrations were unchanged after a 2-week interval (69 vs 69 ng/L, P = 0.55) but fell slightly immediately following dialysis (69 vs 61 ng/L, P < 0.001). Established coronary artery disease (59% vs 22%), peripheral vascular disease (38% vs 4%) and diabetes (18% vs 7%) were more prevalent (P < 0.05) in those in the highest quartile for hsTnT compared with those in the lowest quartile. CONCLUSION: Almost all in-centre haemodialysis patients have elevated troponin T in their baseline stable state and this appears unchanged over a 2-week interval. Such a high rate of baseline elevation of hsTnT may lead to confusion in managing acute coronary syndrome in this group of patients, particularly when symptoms are atypical. We recommend that if Troponin I assay is unavailable then baseline hsTnT concentrations are measured periodically in all haemodialysis patients.

Interpretation and management of INR results: a case history based survey in 13 countries.

INTRODUCTION: Standardisation of treatment with vitamin K antagonists (VKAs) is still an issue after 60 years of use. The study aimed to explore aspects of VKA monitoring in primary and secondary care. METHODS: Two case histories were distributed to physicians in 13 countries. Case history A focused on a patient with atrial fibrillation on stable anticoagulation (latest INR 2.3). Physicians were asked about frequency of INR measurement, when to change the VKA dose, and the patient's annual risk of ischemic stroke and bleeding. Case history B focused on a patient with an unexpected INR of 4.8, asking for the patient's 48-hour bleeding risk, the immediate dose reduction and time until a repeat INR. RESULTS: Altogether, 3016 physicians responded (response rate 8 - 38%), of which 82% were from primary care and 18% from secondary care. Answers varied substantially within and between countries regardless of level of care and VKA used. Median number of weeks between INR measurements was 4 - 6 weeks. Median threshold INR for increasing or decreasing the VKA dose was 1.9 and 3.1, respectively. Risk of ischemic stroke and bleeding were overestimated 2 - 3 times. In case history B, the median dose reduction the two first days was 75% for GPs and 55% for specialists, irrespective of estimates of bleeding risk; with one week to a repeat INR. CONCLUSION: Variation in VKA monitoring is substantial implying clinical consequences. Guidelines seem either unknown or may be considered impracticable. Further efforts towards standardisation of VKA management are needed.