Routinely measured cardiac troponin I and N-terminal pro-B-type natriuretic peptide as predictors of mortality in haemodialysis patients

Superiority of high sensitivity cardiac troponin I over NT-proBNP and adiponectin for 7-year mortality in stable patients receiving haemodialysis

Patients on haemodialysis (HD) have high mortality risk, and prognostic values of the major cardiovascular biomarkers cardiac troponin I (cTnI), N-terminal pro-brain natriuretic peptide (NT-proBNP), and adiponectin should be ascertained over longer follow-up periods using higher-sensitivity assays, which we undertook. In 221 HD patients, levels of high-sensitivity (hs)-cTnI, NT-proBNP, and adiponectin, were measured using high-sensitivity assays, and their associations with all-cause mortality (ACM) and cardiovascular mortality (CVM) were prospectively investigated for 7 years. Higher hs-cTnI and NT-proBNP levels were significant risk factors for ACM and CVM in the Kaplan-Meier analysis. Multivariate Cox proportional hazards analyses in a model including hs-cTnI and NT-proBNP identified log hs-cTnI, but not log NT-proBNP, as an independent risk factor for ACM (HR 2.12, P < 0.02) and CVM (HR 4.48, P < 0.0005). Stepwise analyses identified a high hs-cTnI tertile as a risk factor for ACM (HR 2.31, P < 0.01) and CVM (HR 6.70, P < 0.001). The addition of hs-cTnI to a model including age, CRP, DM, and NT-proBNP significantly improved the discrimination of ACM and CVM each over 7 years. Conclusively, hs-cTnI was superior to NT-proBNP and adiponectin in predicting ACM and CVM over 7 years in HD patients, suggesting the significance of baseline hs-cTnI measurements in long-term management.

Association between Myocardial Oxygen Supply and Demand and Myocardial Injury in Patients with End-Stage Kidney Disease

AIM

In patients with end-stage kidney disease (ESKD), it is unclear whether an imbalance between myocardial oxygen supply and demand leads to myocardial injury (MI). This study clarifies the association between the balance of the rate pressure product (RPP), consisting of the systolic blood pressure multiplied by the pulse rate (PR), a marker for myocardial oxygen demand, and hemoglobin (Hb), a marker for oxygen supply, with MI.

METHODS

A total of 283 consecutive unselected patients for hemodialysis were enrolled in this retrospective, cross-sectional study, and were divided into four groups according to Hb levels (high or low) and RPP. Potential imbalances between myocardial oxygen supply and demand were defined as patients with simultaneous high RPP and low Hb levels. The odds ratio (OR) for MI, defined as cardiac troponin T (cTnT) of ≥ 0.15 ng/mL was investigated using logistic regression analysis between the four patient groups.

RESULTS

The mean age was 68.7 years, 71.3% were men, and 52.6% had diabetes. The mean Hb level was 9.0 g/dL, and 20.5% of patients were latently diagnosed with MI. The median RPP and cTnT level was 12,144 and 0.083 ng/mL, respectively. When exposed to simultaneous high RPP with low Hb, OR significantly increased compared with that of the well-balanced group (RPP ＜12,500 and Hb ≥ 9.0 g/dL; OR 3.63, p＜0.05). Similar results were obtained in multivariate analysis after adjusting for confounding variables. These associations were enhanced or weakened when the Hb cut-off level became lower (Hb=8 g/dL) or higher (Hb=10 g/dL).

CONCLUSIONS

As the myocardial oxygen supply and demand balance in patients with ESKD is potentially associated with MI, appropriate management for blood pressure, PR, and anemia may prevent MI.

Serum potassium in elderly heart failure patients as a predictor of readmission within 1 year

Blood potassium levels are associated with adverse outcomes in patients with congestive heart failure (HF). However, it is unclear whether there are differences in outcome events in elderly patients with different blood potassium levels at the time of emergency readmission within 1 year. This study used data from patients hospitalized with HF, integrating electronic medical records from the PhysioNet restricted health data database and external outcome data. We conducted a retrospective study of HF patients aged 60 years and older, using baseline data, comorbidities, laboratory tests, and medication use as covariates to analyze the effect of serum potassium levels on outcome events, with the primary outcome being readmission within 1 year. A priori was used to calculate the sample size, and this retrospective cohort study included a total of 788 elderly HF patients, of whom 20.3% had hypokalaemia (K⁺  < 3.5 mmol/L) and 14.7% had hyperkalemia (K⁺  > 4.7 mmol/L). According to a multivariate Cox regression model, patients with hyperkalemia had a shorter time interval between readmissions within 1 year, with a hazard ratio (HR) and its 95% CI of 1.134 (1.006-1.279). Three models were used to analyze patients with different blood potassium levels and, after correction, the high potassium group was at high risk relative to the low and normal groups, with significant differences in outcome events, with HRs and their 95% CI of 1.266 (1.03-1.557), 1.245 (1.01-1.534), and 1.439 (1.142-1.812), respectively. The robustness of the model was also demonstrated by competing risk models with subgroup analysis, showing that blood potassium levels had a stable effect on outcome events and were not altered by covariates (age, sex, diabetes, chronic kidney disease, NT-proBNP, high-sensitivity troponin, and glomerular filtration rate). The results show that high blood potassium levels are associated with the outcome event of readmission within 1 year in elderly patients with HF. Blood potassium levels at the time of the first hospitalization may therefore be a valuable predictor.

Association between Intra- and Extra-Cellular Water Ratio Imbalance and Natriuretic Peptides in Patients Undergoing Hemodialysis

Natriuretic peptides are associated with malnutrition and volume overload. Over-hydration cannot simply be explained by excess extracellular water in patients undergoing hemodialysis. We assessed the relationship between the extracellular and intracellular water (ECW/ICW) ratio, N-terminal pro-B-type natriuretic peptide (NT-proBNP), human atrial natriuretic peptide (hANP), and echocardiographic findings. Body composition was examined by segmental multi-frequency bioelectrical impedance analysis in 368 patients undergoing maintenance dialysis (261 men and 107 women; mean age, 65 ± 12 years). Patients with higher ECW/ICW ratio quartiles tended to be older, were on dialysis longer, and had higher post-dialysis blood pressure and lower body mass index, ultrafiltration volume, serum albumin, blood urea nitrogen, and creatinine levels (p < 0.05). The ECW/ICW ratio significantly increased with decreasing ICW, but not with ECW. Patients with a higher ECW/ICW ratio and lower percent fat had significantly higher natriuretic peptide levels. After adjusting for covariates, the ECW/ICW ratio remained an independent associated factor for natriuretic peptides (β = 0.34, p < 0.001 for NT-proBNP and β = 0.40, p < 0.001 for hANP) and the left ventricular mass index (β = 0.20, p = 0.002). The ICW-ECW volume imbalance regulated by decreased cell mass may explain the reserve capacity for fluid accumulation in patients undergoing hemodialysis.

The influence of age and sex on the prognostic importance of traditional cardiovascular risk factors, selected circulating biomarkers and other markers of subclinical cardiovascular damage

PURPOSE OF REVIEW

There is an increasing need for improved risk stratification to better individualize cardiovascular preventive measures. Although age and sex are strong and easily obtained cardiovascular risk factors (CVRFs), their influence on the prognostic importance of other CVRF, circulating biomarkers and other markers of subclinical cardiovascular damage has not previously been systematically and critically appraised. Therefore, we have revisited the European MORGAM and the Danish MONI10 cohorts.

RECENT FINDINGS

Theoretically, the relative risk of many CVRF is expected to be lower in older healthy individuals due to a combination of selection bias by disease, higher absolute risk primarily due to older age, and the fact that the CVRF and markers may primarily influence or reflect early parts of the cardiovascular disease process. This influence of age may vary between sexes, as the cardiovascular disease process is delayed and possibly different in women compared with men.

SUMMARY

Adjusted for the remaining Systematic COronary Risk Evaluation (SCORE) CVRF, higher SBP, serum cholesterol, soluble urokinase-type plasminogen activator receptor, left ventricular mass index and atherosclerotic plaques were more closely associated with outcomes in individuals younger than 52 years with some sex-specific differences, whereas higher N-terminal pro-brain natriuretic peptide and urine albumin/creatine ratio were more closely associated with outcomes in subjects aged 61 or 71 years.