The effect of hemodialysis on cardiac enzyme levels and echocardiographic parameters

Mid-regional pro-atrial natriuretic peptide levels before and after hemodialysis predict long-term prognosis

BACKGROUND

Mid-regional pro-atrial natriuretic peptide (MR-proANP) is a strong prognostic biomarker in cardiovascular disease but there is limited data for its use among patients undergoing dialysis.

METHODS

This was a cohort study of patients receiving maintenance hemodialysis from two Danish centers. Blood sampling and echocardiography were performed before and after a dialysis session. We calculated the area under the curve (AUC) for the receiver operating characteristics for diagnosing heart failure and Cox regressions for cardiovascular events and all-cause mortality.

RESULTS

Of the 306 patients, 284 (93%) had MR-proANP measurements both before and after dialysis. Median concentration was 642 pmol/L (IQR 419-858) before and 351 pmol/L (IQR 197-537) after dialysis, a mean decrease of 330 pmol/L (43%, CI 296-364, P < 0.001). MR-proANP concentration both before and after dialysis was negatively correlated to left ventricular ejection fraction with no difference in predictive ability for heart failure, AUC before and after dialysis were 0.60 (CI 0.50-0.70) and 0.61 (CI 0.51-0.71) (P = 0.40). Median follow-up was 32 months (IQR 31-33), during which 99 patients (32%) had a cardiovascular event and 110 (36%) died. A doubling of MR-proANP concentration was associated with a hazard ratio (HR) of 1.6 (CI 1.3-1.9) before and 1.7 (CI 1.4-2.0) after dialysis for mortality and a HR of 1.5 (CI 1.2-1.9) before and 1.4 (CI 1.2-1.7) after dialysis for cardiovascular events (all P < 0.001).

CONCLUSION

The MR-proANP concentration is elevated among patients undergoing hemodialysis and decreases during dialysis. MR-proANP concentration both before, after and intra-dialysis change strongly predicted cardiovascular events and all-cause mortality.

High sensitivity Troponin-I levels in asymptomatic hemodialysis patients

Reduction in renal clearance and removal by hemodialysis adversely affect the level and utility of high-sensitivity troponin I (hsTnI) for diagnosis of acute myocardial infarction (AMI) in hemodialysis (HD) patients. Furthermore, HD process itself might cause undesirable myocardial injury and enhance post HD hsTnI levels. This comparative cross-sectional study was conducted to compare the hsTnI levels between 100 asymptomatic HD patients and their 107 matched non-chronic kidney disease (CKD) population. The hsTnI levels in HD group were higher than non-CKD group [median (IQR): 54.3 (20.6-152.7) vs. 18 (6.2-66.1) ng/L, p < .001)]. The hsTnI levels reduced after HD process from 54.3 (20.6-152.7) ng/L in pre-HD to 27.1 (12.3-91.4) ng/L in post-HD (p = .015). Of interest, 25% of HD patients had increment of hsTnI after HD and might represent HD-induced myocardial injury. The significant risk factors were high hemoglobin level and high blood flow rate. In conclusion, the baseline hsTnI levels in asymptomatic HD patients were higher than non-CKD population. The dynamic change of hsTnI over time would be essential for the diagnosis of AMI. Certain numbers of asymptomatic HD patients had HD-induced silent myocardial injury and should be aggressively investigated to prevent further cardiovascular mortality.

Prognostic value of high-sensitive cardiac troponin I in asymptomatic chronic hemodialysis patients

INTRODUCTION

Increased levels of cardiac troponins (cTn) are a hallmark of acute myocardial infarction (AMI), along with symptoms and electrocardiographic (ECG) changes. Stably elevated cTn concentrations are frequently observed in asymptomatic patients with chronic kidney disease (CKD) and/or on hemodialysis (HD); the meaning of this elevation, as assessed by conventional techniques, remains unclear. Aim of our study was to evaluate the clinical significance of cTnI levels in asymptomatic HD patients by employing a newer high-sensitive cTnI (hs-cTnI) assay.

METHODS

We enrolled 49 patients undergoing regular HD treatment for more than 3 months; all patients were asymptomatic for chest pain and had no history of acute coronary syndrome in the past 2 months. For every patient we measured hs-cTnI, cTnI and brain natriuretic peptide (BNP) before initiation of one HD session at baseline (T0), after 3 (T1) and 9 months (T2). Demographic, anamnestic, dialytic and echocardiographic characteristics of the examined population were evaluated. We also recorded the number of cardiovascular events from T0 to 12 months after T2.

RESULTS

Fifteen patients were lost to follow-up: 6 died, 2 underwent kidney transplantation, 7 did not match the inclusion criteria later during observation. At T0 (49 patients) we observed 14 hs-cTnI positive patients vs. 4 standard c-TnI positive patients (28,5% vs 8,1%); at T1 (40 patients) 16 vs 3 (26.4% vs 7.5%); at T2 (34 pz) 9 vs 0 (26.4% vs 0%). During the study we recorded 10 cardiovascular events, 8 of which in patients that were hs-cTNI positive, leading to death in 3. Hs-cTnI levels were predictive of cardiovascular events at all times and predictive of cardiovascular mortality at T0 and T1 (p < 0.001). In a multivariate analysis, a history of coronary artery disease (CAD) was an independent variable of high hs-cTnI levels at T0 (p < 0.04) and T1 (p < 0.03).

CONCLUSIONS

Our study shows that a novel sensitive assay detects more asymptomatic HD patients compared to previously used methods, being at the same time predictive of cardiovascular mortality and morbidity. The only independent variable of high hs-cTnI concentrations was a positive history of cardiovascular disease, suggesting a possible role of hs-cTnI in identifying a high-risk subset of patients.

Long-term impacts of hemodialysis on the right ventricle: Assessment via 3-dimensional speckle-tracking echocardiography

BACKGROUND

Right ventricular (RV) dysfunction is a major cause of death in patients undergoing maintenance hemodialysis (MHD). We used 3-dimensional speckle-tracking echocardiography (3DSTE) to evaluate long-term impacts of MHD on RV function.

HYPOTHESIS

In this study, RV dysfunction in MHD patients will be revealed and studied in depth by 3DSTE.

METHODS

Echocardiography was performed on 110 consecutively enrolled individuals: 30 controls and 80 patients with MHD. Conventional echocardiographic parameters and 3DSTE parameters were obtained and compared between groups. Univariate and multivariate logistic regression analysis identified independent predictors of intradialytic hypotension (IDH).

RESULTS

Compared with the control group, RV end-diastolic volume (RVEDV) was markedly enlarged (46.1 ± 11.8 mL/m² vs 42.3 ± 8.6 mL/m² ; P = 0.047), whereas RV ejection fraction (RVEF) was significantly lower in the MHD group (50.6% ± 5.8% vs 55.2% ± 3.7%; P < 0.001). RV global, septal, and lateral wall longitudinal strains were also decreased in the MHD group (-18.2 ± 3.6 vs -22.6 ± 4.3%; -13.1 ± 3.8 vs -17.5 ± 5.5%; and -23.4 ± 4.7 vs -27.7 ± 4.0%, respectively; all P < 0.001). RVEF (odds ratio [OR]: 0.72, 95% confidence interval [CI]: 0.51 to 1.01, P = 0.038) and history of diabetes (OR: 11.14, 95% CI: 1.16 to 106.71, P = 0.036) were 2 independent predictors of IDH. Ultrafiltration rate was an independent factor associated with RVEF (β = -0.01, 95% CI: -0.019 to 0.001, P = 0.039).

CONCLUSIONS

RVEF by 3DSTE could be an important predictor of IDH in MHD patients, and lower ultrafiltration rate was protective for RVEF. 3DSTE may have potential in RV evaluation and risk stratification in MHD patients.

Troponin I Levels in Asymptomatic Hemodialysis Patients

Background: End-stage renal disease (ESRD) represents a situation in which persistently elevated levels of cardiac troponins I (cTnI) are frequently found in the absence of clinically evident cardiac disease. Moreover, the effect of hemodialysis (HD) on cTnI levels is not definitively elucidated. The aim of this study was to investigate the effects of HD on cTnI levels in ESRD patients. Methods: We enrolled 30 asymptomatic ESRD patients on maintenance HD. All the patients were dialyzed thrice weekly. We compared each other's cTnI levels obtained before HD sessions (pre-HD) and cTnI levels obtained before and after HD sessions (post-HD). Results: The median value of baseline cTnI, measured before the first dialysis session of the week, was 0.018 ng/mL (interquartile range 0.012-0.051) and elevated levels (>0.034 ng/mL) were found in 9 (30%) patients. Pre-HD cTnI levels showed a statistically significant decrease between the first and the second weekly HD sessions (from 0.018 to 0.016 ng/mL; p = 0.002), while no difference was observed between the second and the third sessions over the week. Finally, no statistically significant differences were found between pre-HD and post-HD cTnI levels, considering each HD session and the averaged cTnI values. Conclusions: Our results indicate that HD does not significantly affect cTnI levels. Even when statistically significant, the observed changes were without clinical relevance indicating that HD does not affect by itself the diagnostic accuracy of cTnI assay in ESRD patients.

Creatine-kinase and dialysis patients, a helpful tool for stratifying cardiovascular risk?

BACKGROUND AND AIMS

Hemodialysis patients have an enhanced risk for cardiovascular events. Cardiac biomarkers provide useful information for stratifying their risk. However the prognosis value of creatine kinase MB isoenzyme (CKMB) has not yet been validated in this population. The aim of the present study is to determine the predictable value of CK-MB in hemodialysis.

METHODS

A cohort of 211 hemodialysis patients (58.3% male, median age 73 (60-80) years) were followed for 39 (19-56) months. Cardiac biomarkers including CKMB were recorded at baseline. Factors associated to CKMB and prognosis value of this biomarker was studied.

RESULTS

The median value of CKMB was 1 (1-2) ng/mL with no patient exceeding normal laboratory values. Previous heart disease, diabetes mellitus, peripheral vascular disease and systolic and diastolic dysfunction were associated with higher levels of CKMB. Ninety-four patients (44.5%) cardiovascular events were recorded. CKMB levels ≥2ng/mL was independently associated to cardiovascular events during the follow up after adjusting. Adding CKMB to a model including several variables for predicting cardiovascular events, resulted in 17% improvement in risk discrimination (IDI) with a relative IDI of 9.9% (p=0.04).

CONCLUSIONS

CKMB is a good marker for stratifying cardiovascular risk in hemodialysis patients and adds prognosis information to other well known independent predictors for cardiovascular events.

Serum cardiac troponin T and effective blood flow in stable extracorporeal dialysis patients

Purpose

We examined the association between extracorporeal dialysis (ED)-related effective blood flow (eQB) and serum cardiac troponin T (cTnT) as a possible indicator of silent myocardial damage in stable ED patients.

Methods

In a cross-sectional study, cTnT was determined in 247 ED patients dialyzed using stable eQB and dialysate flow (QD). In a prospective study, 91 patients were switched from low-flux (LF) to high-flux (HF) hemodialysis (HD), and subsequently, the eQB increased, and the QD decreased; 65 patients continued LF-HD with stable eQB and QD. Clinical/laboratory evaluations were performed at 0, 15, 36, and 53 weeks from the start of the study.

Results

In the cross-sectional study, the main cTnT predictors were dialysis vintage, age, eQB, phosphorus, and C-reactive protein. Patients with cTnT levels in the highest quartile were excluded from the analysis, and subjects dialyzed with eQB ≤316 ml/min exhibited lower cTnT levels compared with patients dialyzed with higher eQB (P = 0.002). The all-cause and cardiac mortality rates of 154 patients, without changes in ED modality for up to 42 months, were associated with the initial cTnT concentrations but not with the initial eQB. In the prospective study, higher values for eQB and cTnT were observed during HF-HD at weeks 36 (P = 0.045) and 53 (P = 0.01) of the present study. The initial cTnT, ∆eQB, and ∆albumin influenced the ∆cTnT. The all-cause and cardiac mortality rates were not different between LF and HF groups at 21 months after the prospective study was completed.

Conclusion

In stable ED patients, higher eQB rates and QB/QD values might contribute to silent myocardial injury, particularly in patients with lower cTnT levels, but do not affect the outcome of ED patients.

Electronic supplementary material

The online version of this article (doi:10.1007/s11255-015-1165-z) contains supplementary material, which is available to authorized users.

NT-proBNP and troponin T levels differ after haemodialysis with a low versus high flux membrane

BACKGROUND

Brain natriuretic peptide (BNP), N-terminal-proBNP (NT-proBNP), and high sensitive cardiac troponin T (TnT) are markers that are elevated in chronic kidney disease and correlate with increased risk of mortality. Data are conflicting on the effect of biomarker levels by hemodialysis (HD).Our aim was to clarify to what extent HD with low-flux (LF) versus high-flux (HF) membranes affects the plasma levels of BNP, NT-proBNP, and TnT.

METHODS AND MATERIALS

31 HD patients were included in a crossover design, randomized to start dialysis with a LF-HD or HF-HD dialyzer. Each patient was his/her own control. The dialyses included in the study were the first treatments of two consecutive weeks with each mode of dialysis. Patients normally on hemodiafiltration (HDF) also performed a HDF the third week. Values after HD were corrected for extent of ultrafiltration.

RESULTS

During LF-HD the biomarkers NT-proBNP and TnT increased (15 versus 6%, P ≤ .001) while there was a slight decrease in BNP (P<.05). During HF-HD the NT-proBNP, BNP and TnT levels decreased (P ≤ .01 for all). During HDF all three markers decreased (P<.01 for all). The rise in TnT during LF-HD correlated with dialysis vintage (months on HD, r = .407, P = .026), Kt/V-urea (r = .383, P = .037), HD time in hours/treatment (r = .447, P = .013) and inversely with residual urinary output (r = -.495, P = .005). The baseline levels of BNP and NT-proBNP correlated with blood pressure.

CONCLUSIONS

Cardiac biomarkers increase slightly during LF-HD. A HF-HD eliminates the biomarkers and can mask increases caused by, e.g., myocardial infarction.