Christopher P. Streather

Cardiac structural and functional abnormalities in end stage renal disease patients with elevated cardiac troponin T

Objectives: To identify in a prospective observational study the cardiac structural and functional abnormalities and mortality in patients with end stage renal disease (ESRD) with a raised cardiac troponin T (cTnT) concentration. Methods: 126 renal transplant candidates were studied over a two year period. Clinical, biochemical, echocardiographic, coronary angiographic, and dobutamine stress echocardiographic (DSE) data were examined in comparison with cTnT concentrations dichotomised at cut off concentrations of < 0.04 μg/l and < 0.10 μg/l. Results: Left ventricular (LV) size and filling pressure were significantly raised and LV systolic and diastolic function parameters significantly impaired in patients with raised cTnT, irrespective of the cut off concentration. The proportions of patients with diabetes and on dialysis were higher in both groups with raised cTnT. With a cut off cTnT concentration of 0.04 μg/l but not 0.10 μg/l, significantly more patients had severe coronary artery disease and a positive DSE result. The total ischaemic burden during DSE was similar in cTnT positive and negative patients, irrespective of the cut off concentration used. LV end systolic diameter index and E:Ea ratio were independent predictors of cTnT rises ⩾ 0.04 μg/l and ⩾ 0.10 μg/l, respectively. Diabetes was independently associated with cTnT at both cut off concentrations. Mortality was higher in all patients with raised cTnT. Conclusions: Patients with ESRD with raised cTnT concentrations have increased mortality. Raised concentrations are strongly associated with diabetes, LV dilatation, and impaired LV systolic and diastolic function, but not with severe coronary artery disease.

Evaluation of ischaemia-modified albumin as a marker of myocardial ischaemia in end-stage renal disease.

The early diagnosis of myocardial ischaemia is problematic in patients with ESRD (end-stage renal disease). The aim of the present study was to determine whether IMA (ischaemia-modified albumin) increases during dobutamine stress and detects myocardial ischaemia in patients with ESRD. A total of 114 renal transplant candidates were studied prospectively, and all received DSE (dobutamine stress echocardiography). IMA levels were taken at baseline and 1 h after cessation of DSE. A total of 35 patients (31%) had a positive DSE result. Baseline IMA levels were not significantly different in the DSE-positive and -negative groups. The increase in IMA was significantly higher in the DSE-positive group compared with those with no ischaemic response (26.5 +/- 19.1 compared with 8.2 +/- 9.6 kU/l respectively; P = 0.007; where kU is kilo-units). From ROC (receiver operator charactertistic) curve analysis, the optimal IMA increase to predict an ischaemic response was 20 kU/l, with a sensitivity of 81% and a specificity of 72% [area under the curve, 0.80 (95% confidence interval, 0.44-0.94); P = 0.03]. There were 18 deaths, ten of which were cardiac in nature over a follow up period of 2.25 +/- 0.71 years. An increase in IMA > or = 20 kU/l was associated with significantly worse survival (P = 0.02). In conclusion, IMA is a moderately accurate marker of myocardial ischaemia in ESRD. Patients with an increase in IMA > or = 20 kU/l during DSE had significantly worse survival.

Raised plasma N-terminal pro-B-type natriuretic peptide concentrations predict mortality and cardiac disease in end-stage renal disease

N-terminal pro-B-type natriuretic peptide (NT-proBNP) concentrations are raised in a proportion of patients with heart failure and acute coronary syndrome and provide diagnostic and prognostic information. Inclusion cut-off values vary according to age, sex and estimated glomerular filtration rate (eGFR).1,2 Raised NT-proBNP concentrations are found in a proportion of patients with end-stage renal disease (ESRD). The significance and reasons for this remain uncertain. The objective of this study was to investigate whether NT-proBNP predicts mortality in a group of patients with ESRD. The secondary end point was to examine differences in patients with and without raised NT-proBNP, according to the cut-off value that best predicted mortality. One hundred and forty renal transplant candidates were prospectively studied. Long-term survival status was obtained in all patients. The study was approved by the local ethics committee. All participants gave written informed consent. All patients had baseline transthoracic echocardiography, dobutamine stress echocardiography (DSE) and coronary angiography. The protocol for these was previously described.3 A positive DSE response was described by the occurrence under stress of hypokinesia, akinesia or dyskinesia in one or more resting normal segments or worsening of wall motion in one or more resting hypokinetic segments. Significant coronary artery disease (CAD) was defined as luminal stenosis > 70% in one or more epicardial artery. Whole blood venous samples were collected at the time of DSE before infusion of dobutamine. Cardiac troponin T …

The diagnostic and prognostic value of tissue Doppler imaging during dobutamine stress echocardiography in end-stage renal disease.

ObjectiveTo determine whether a quantitative measurement of peak systolic velocity (PSV) during dobutamine stress echocardiography (DSE) detects severe coronary artery disease (CAD) and predicts mortality in patients with end-stage renal disease. MethodsOne hundred and forty renal transplant candidates had DSE and coronary angiography. DSE analysis was performed using conventional visual wall motion assessment, longitudinal PSV, and combining the two modalities. Failure of PSV to rise by more than 50% predicted an ischemic response. Significant CAD was defined as luminal stenosis greater than 70%. ResultsThe number of positive DSE studies according to conventional, PSV, and combined criteria was 41 (30%), 42 (31%), and 46 (34%) respectively. Forty patients (29%) had significant CAD at angiography. The sensitivity, specificity, positive and negative predictive values for conventional DSE analysis were 84, 91, 86, and 90% respectively. The same values for PSV analysis were 86, 92, 86, and 91%, respectively. The same values for the combination of visual and PSV analysis were 88, 94, 87, and 92% respectively. The differences between the three methods were not statistically significant. Sensitivity for single-vessel CAD (P=0.05) and circumflex artery disease (P=0.05) diagnosis was higher with PSV compared with conventional DSE analysis. Failure of PSV to rise by more than 50% during DSE was associated with significantly increased mortality (P=0.001). ConclusionA quantitative interpretation of DSE, based on the percentage rise of PSV during stress, accurately detects CAD and predicts prognosis in end-stage renal disease.