Differences in cardiac troponin I and T levels measured in asymptomatic hemodialysis patients with last generation immunoassays

Previous studies reported cardiac troponin I (cTnI) and T (cTnT) levels to be higher than normal in a significant proportion of asymptomatic chronic hemodialysis (HD) patients without evidence of acute myocardial injury. We have therefore evaluated in such patients the accuracy of cTnI and cTnT determinations measured with last generation assays. Fifty chronic HD patients (34 males) without symptoms of acute myocardial ischemia were studied. Their mean age (+/-SD) was 64.4+/-12.7 years, 22 patients (44%) had an history of cardiac ischemic disease and 19 (38%) were diabetics. Serum cardiac markers were measured with last generation assays before and after a single HD session and in a control group including 30 hospitalized patients without renal failure. The cTnI were determined with Dimension RxL "Improved method" assay (Dade Behring), the cTnT with Elecys "Third generation" assay (Roche Diagnostics) and the creatine kinase (CK) with Integra (Roche Diagnostics). The cTnI were also simultaneously determined with the assay previously used at our institution (Dimension RxL, Dade Behring), indicated as old-method-cTnI. With the last generation assay only 1 patient (2%) had elevated cTnI (>0.1 microg/l) in the study group compared to none in the control group (P=NS). Instead, with the old-method-cTnI assay 11 patients (22%) had elevated (>0.3 microg/l) predialysis cTnI levels (P<0.01 compared to the "Improved method" assay). The predialysis cTnT levels were higher than normal (>0.1 microg/l) in 23 patients (46%), compared to none in the control group (P<0.01). The CK levels were elevated (>170 IU/L) in 4 dialysis patients (8%) compared to one (3,3%) in the control group (P=NS). The cTnT levels slightly but non-significantly diminished during dialysis (from 0.102+/-0.070 to 0.085+/-0.067 mug/l, P=NS), while in the same time no changes were observed for cTnI and CK levels. In conclusion, the specificity of cTnI determinations in HD patients is greatly improved by the last generation assay (from 78 to 98%), and is actually similar to that observed in a population with normal renal function. Therefore cTnI, determined with the last generation assay used in the present study, can be reliably used for the diagnosis of acute coronary syndromes in HD patients. Instead, cTnT levels remain higher than normal in a significant proportion of asymptomatic HD patients (46%) and the reasons for this fact need further investigations.     

Cardiac Findings in Asymptomatic Chronic Hemodialysis Patients with Persistently Elevated Cardiac Troponin I Levels

Background. The prevalence and significance of higher than normal cardiac troponin I (cTnI) levels in asymptomatic chronic hemodialysis (HD) patients remains a source of discussion. The aim of the present study was to evaluate the prevalence of higher than normal cTnI levels in asymptomatic HD patients, as determined by the last generation of immunoassay, and to perform further cardiological investigations in those patients with persistently elevated cTnI levels. Methods. All chronic HD patients in our center who had exhibited no symptoms of coronary artery disease (CAD) during the previous four weeks were screened. cTnI levels were determined before dialysis in all patients using the last generation AccuTnI? assay (UniCel DxI 800, Beckman Coulter). The cTnI levels of those patients with elevated cTnI at the screening evaluation were then measured monthly for six months. We were thus able to identify a group of patients with persistently elevated cTnI levels (> 3 consecutive months) who subsequently underwent cardiac echography and dipyridamole-exercise (D-E) thallium testing. If stress myocardial ischemia was detected, a coronary angiography was then performed. Results. Fifty patients (32 males) were included: mean age 62.8 ± 13.6 years, 20 (40%) with a history of CAD, and 21 (42%) diabetic. At the initial screening, the mean cTnI concentration was 0.05 ± 0.06 μg/L and the cTnI levels were higher than normal (> 0.09 μg/L) in six patients (12%). In the follow-up, the cTnI normalized immediately in two patients but remained persistently elevated (range, 0.10–0.48 μg/L) in four (8%). These four patients (all males, one diabetic) had a mean age of 70.2 ± 6.6 years, and all had heart failure with a history of severe CAD with previous myocardial infarction (n = 4), coronary stenting (n = 3), and/or bypass (n = 2). D-E thallium imaging showed reversible myocardial ischemia in all. The stress ischemia involved one to four cardiac segments and was slight to moderate in three patients and severe in the diabetic patient. A coronary angiogram was performed in all patients, and showed lesions of variable severity: severe three-vessel CAD with severe systolic dysfunction in two patients (including the diabetic), and non-critical/peripheral coronary stenosis in the other two. Conclusions. Among the asymptomatic HD patients in our center, we identified four (8%) with persistently elevated cTnI levels, as determined using the last generation AccuTnI? assay. All of them had a history of severe CAD with heart failure and exhibited reversible myocardial ischemia upon D-E thallium imaging; coronary angiography revealed coronary lesions of variable severity. Overall, our data indicate that persistent low-grade cTnI elevation occurs in HD patients having longstanding severe cardiac disease, but, from our data, it is difficult to reach a conclusion as to the best clinical approach for this group of patients.     

Lack of agreement between left ventricular volumes and ejection fraction determined by two-dimensional echocardiography and contrast cineangiography in postinfarction patients

OBJECTIVE: To assess the agreement between left ventricular (LV) volumes and ejection fraction (EF) determined by two-dimensional echocardiography (2-D echo) and by cineangiography in postinfarction patients. Design: LV end-diastolic and end-systolic volumes indexed (EDVI and ESVI) to body surface area as well as EF were determined by both methods in all patients. Setting: Multicenter trial conducted in five university hospitals. PATIENTS: 63 patients, 61 male, two female, mean age 55.5 +/- 10.4 years, suffering from a recent myocardial infarction. Eighty-one pairs of measurements were available. METHODS: The results of biplane 2-D echo measures, using apical four-chamber (4C) and two-chamber (2C) views were compared to those of a 30 degrees right anterior oblique cineangiography projection, using either the apical method of discs or the area-length 2-D echo method. Moreover, eyeball EF was estimated at 2-D echo and cineangiography, and was compared to the conventional methods. The agreement between results was assessed by the Bland and Altman method. RESULTS: The agreement between 2-D echo and cineangiography results was poor. Mean differences (MD) were -21.8 (EDVI, ml/m(2)), -9.5 (ESVI, ml/m(2)), and -0.9 (EF, %), respectively for 2-D echo method of discs versus cineangiography, and -23.2, -9.3, and -5.7 for area-length 2-D echo versus cineangiography. For EF (%), MD was -3.6 for eyeball cineangiography versus cineangiography, -1.3 for eyeball 2-D echo versus method of discs, and +0.30 for eyeball 2-D echo versus area-length 2-D echo, respectively. Two-dimensional echo is likely to underestimate LV volumes compared to cineangiography, especially for largest volumes. Even for EF, discrepancies are large, with a lack of agreement of 21%-25% between conventional methods, but agreement is better between eyeball EF and usual methods. CONCLUSIONS: Even with modern echocardiographic devices, agreement between 2-D echo and cineangiography-derived LV volumes and EF remains moderate, and both methods must not be considered interchangeable in clinical practice.     

Conversion,dissociative amnesia,and Ganser syndrome in a case of “chameleon” syndrome: Anatomo-functional findings

The term “chameleon” was first used in the seventeenth century by Sydenham to describe a patient with a protean semiology. We report a single case of “chameleon” syndrome that challenges the current international criteria for somatoform disorders, dissociative amnesia, and Ganser syndrome. The florid symptoms were as follows: anterograde and retrograde amnesia (including semantic, episodic, and procedural deficits), loss of identity, atypical neuropsychological impairment (approximate answers), left sensitive and motor deficit, and left pseudochoreoathetosis movement disorders. Additional behavioral disorders included the following: anxiety, clouded consciousness, hallucinations, and “belle indifference”. A single photon emission computed tomography examination showed bilateral temporal, frontal and a right caudate (in the head of the caudate nucleus) hypoperfusion concordant with a common mechanism of repression in these disorders.