Helen Gregson

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.

Circulating cardiac troponin-T in patients before and after renal transplantation.

BACKGROUND The diagnostic and prognostic use of cardiac troponin T (cTnT) in patients with renal failure has been questioned. Raised serum concentrations of cTnT, with no apparent signs of cardiac damage using conventional methods of detection, have been reported. We aimed to relate circulating concentrations of cTnT to improved renal function following renal transplantation over a one-year period. METHOD Plasma cTnT was analysed from patients with end stage renal disease before and after transplantation and subsequently at 1, 3, 6 and 12 months. Eight patients had diabetes, 14 had hyperlipidaemia, 8 were smokers and 4 were ex-smokers; all were hypersensitive. RESULTS At the time of transplantation, 3 of the 32 patients (9.4%) had plasma cTnT concentrations above 0.1 microg/l. In addition to these three patients, five others showed raised cTnT over the one-year period. CONCLUSIONS The overall trend in circulating cTnT concentrations did not seem to be affected by improved renal function. However, all of the patients that had raised cTnT concentrations at any stage of the one-year period had explainable pathologies or were exposed to multiple cardiac risk factors.

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.

Echocardiography‐based score to predict outcome after renal transplantation

Background: Given the high cardiac mortality of renal transplant recipients, identification of high-risk patients is important to offer appropriate treatment before transplantation. Aim: To determine patients with high mortality after renal transplantation despite selection according to current criteria. Methods: Preoperative parameters were collected from 203 renal transplant recipients over a follow-up time of 3.6 (1.9) years. The primary end point was all-cause mortality. Results: 22 deaths (11%) and 12 cardiac failures (6%) were observed. Non-survivors were older (p⩽0.001), had larger left ventricular end-systolic diameter (LVSD) (p⩽0.001) and end-diastolic diameter (p = 0.002), and lower ejection fraction (p⩽0.001). Left ventricular mass index (p = 0.001), maximal wall thickness (p = 0.006) and the proportion with mitral annular calcification (p = 0.001) were significantly higher in the non-survivors. The risk factors for ischaemic heart disease and exercise test data were not significantly different between the two groups. Four independent predictors of mortality after renal transplantation were identified: age ⩾50 years (p = 0.002), LVESD ⩾3.5 cm (p = 0.002), maximal wall thickness ⩾1.4 cm (p = 0.014) and mitral annular calcification (p = 0.036). The 5-year survival estimates for 0, 1, 2 and 3 prognostic factors were 96%, 86%, 69% and 38%, respectively. No patient had four prognostic factors. In patients ⩾50 years, the 5-year survival estimates for 0, 1 and 2 additional prognostic factors were 73%, 45% and 18%, respectively. Conclusion: In addition to selection according to current guidelines, age and three conventional echocardiography parameters may further improve risk stratification before renal transplantation.

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.

Echocardiographic abnormalities in patients on kidney transplant waiting list.

BACKGROUND Echocardiographic abnormalities are well described in chronic kidney disease (CKD), and associated with increased cardiovascular events (CVEs) and mortality. Little is known regarding progression of these abnormalities in patients awaiting kidney transplantation. METHODS We assessed the progression of echocardiographic variables in patients awaiting kidney transplantation and determined predictors of CVEs and mortality. The study included all patients awaiting kidney transplantation between 2004 and 2010 with repeat echocardiograms at least 1 year apart and at least 1 year after transplantation. RESULTS We assessed 79 patients (57% male, mean age 55 ± 11 years; 27% with diabetes). Sixty-three patients remained on waiting list, and 16 had kidney transplants. Two deaths and 2 CVEs occurred in patients awaiting kidney transplantation. Repeat echocardiograms (31 ± 19 months from baseline) on patients who remained on waiting list showed significant increases in left ventricular mass index (LVMI) (55.3 ± 17.8 vs. 60.5 ± 21.9 g/m2.7, p=0.02) and in left atrium (LA) diameter (3.8 ± 0.6 vs. 4.1 ± 0.8 cm, p=0.02). There were no significant changes in LV fractional shortening (FS) or LV end-systolic and end-diastolic dimensions. Left atrium diameter (p=0.005), systolic dysfunction (p=0.007) and LVMI (p=0.01) were independent predictors of CVEs and mortality. CONCLUSIONS Time on kidney transplant waiting list is associated with progressive increases in LA diameter and LVM, which are markers of adverse outcome.