Comparison between intact and bioactive parathyroid hormone assays in patients with severe heart failure

Effects of parathyroidectomy on plasma PTH fragments and heart rate variability in stage 5 chronic kidney disease patients

INTRODUCTION

Circulating intact parathyroid hormone (iPTH) levels include full-length (1-84) PTH and long C-PTH fragments, but primarily (7-84) PTH, which have been reported to have antagonistic effects on the bones and kidneys. However, their effects on the cardiovascular system remain unclear. In this study, the relationships between the plasma PTH fragments levels and heart rate variability (HRV) in stage 5 chronic kidney disease (CKD5) patients are explored. Furthermore, the effects of parathyroidectomy (PTX) on the above indices are investigated.

METHODS

In this cross-sectional study, 164 healthy controls and 354 CKD5 patients, including 208 secondary hyperparathyroidism (SHPT) subgroup with PTX, were enrolled. Circulating (7-84) PTH levels were calculated by subtracting plasma (1-84) PTH levels from iPTH levels. The HRV parameters were measured using a 24-hour Holter.

RESULTS

The baseline levels of plasma iPTH, (1-84) PTH, and (7-84) PTH in the CKD5 patients were 930.40 (160.65, 1792.50) pg/mL, 448.60 (99.62, 850.45) pg/mL, and 468.20 (54.22, 922.55) pg/mL, respectively. In the CKD5 patients, plasma (1-84) PTH levels were independently correlated with the standard deviation of the normal-to-normal R-R intervals (SDNN) and the standard deviation of the five-minute average of the normal R-R intervals (SDANN). With a median follow up time of 6.50 months after PTX in the SHPT patients (n = 30), improved SDNN and SDANN markers were related with decreased (1-84) PTH levels. Furthermore, an improved SDNN was related with decreased (7-84) PTH levels.

CONCLUSIONS

The CKD5 patients' baseline (1-84) PTH levels were correlated with the SDNN and SDANN. After PTX, an improved SDNN was related with decreased (1-84) PTH and (7-84) PTH levels, while improved SDANN was related with decreased (1-84) PTH levels. No antagonistic effects of (1-84) PTH and (7-84) PTH on HRV were found in the CKD5 patients.

PTH, vitamin D, and the FGF-23-klotho axis and heart: Going beyond the confines of nephrology

BACKGROUND

Profound disturbances in mineral metabolism are closely linked to the progression of chronic kidney disease. However, increasing clinical and experimental evidence indicates that alterations in phosphate homoeostasis could have an even stronger impact on the heart.

AIM

The aim of this review is to provide the reader with an update of how alterations in mineral metabolism are related to direct and indirect cardiotoxic effects beyond the nephrology setting.

RESULTS

Evidence exists that alterations in mineral metabolism that are related to changes in parathyroid hormone (PTH), vitamin D, and the FGF-23-klotho axis have direct pathological consequences for the heart. Alterations in plasma PTH levels are associated with cardiac dysfunction and detrimental cardiac remodelling. Several clinical studies have associated vitamin D deficiency with the prevalence of cardiovascular disease (CV) and its risk factors. Recent evidences support deleterious direct and nonphosphaturic effects of FGF-23 on the heart as hypertrophy development. In contrast, reduced systemic klotho levels are related to CV damage, at least when advanced age is present. In addition, we discuss how these mineral metabolism molecules can counteract each other in some situations, in the context of failed clinical trials on cardiac protection as is the case of vitamin D supplementation.

CONCLUSIONS

Among all mineral components, an increase in systemic FGF-23 levels is considered to have the greatest CV impact and risk. However, it is quite possible that many intracellular mechanisms mediated by FGF-23, especially those related to cardiomyocyte function, remain to be discovered.

Serum NT-proBNP Levels Are Not Related to Vitamin D Status in Young Patients with Congenital Heart Defects

CONTEXT

Hypovitaminosis D frequently occurs in early life and increases with age. Vitamin D has been suggested to influence cardiac performance and N-terminal-pro-type B natriuretic peptide (NT-proBNP) release in adults with heart failure.

OBJECTIVES

To assess the vitamin D status and the impact of hypovitaminosis D on circulating NT-proBNP levels in young patients with congenital heart defects (CHD).

DESIGN AND PATIENTS

This cross-sectional study included the assessment of serum 25-hydroxyvitamin D (25OHD), parathyroid function markers, and NT-proBNP levels in a series of 230 young in-patients (117 females, 113 males; 6.4 (4.0-9.1) years (median, interquartile range)) with CHD.

RESULTS

Serum 25OHD levels <20 ng/mL were detected in 55.3% of patients. Optimal 25OHD levels (>30 ng/mL) occurred in 25% of patients. Serum 25OHD levels inversely correlated with age (r = -0.169, P = 0.013) and height standard deviation score (r = -0.269, P = 0.001). After correction for age, 25OHD negatively correlated with serum PTH levels (β = -0.200, P = 0.002). PTH levels above the upper quartile (44 pg/mL) occurred in 32% of hypovitaminosis D patients. Serum NT-proBNP levels were not correlated with 25OHD and PTH levels.

CONCLUSIONS

Half of the young CHD patients were diagnosed with 25OHD deficiency and a third of hypovitaminosis D patients experienced hyperparathyroidism. Nonetheless, serum NT-proBNP levels were not associated with hypovitaminosis D as well as hyperparathyroidism.

1,25-Dihydroxyvitamin D to PTH(1-84) Ratios Strongly Predict Cardiovascular Death in Heart Failure

OBJECTIVES

Vitamin D deficiency and hyperparathyroidism are common in patients with heart failure (HF). There is a growing body of evidence supporting the role of vitamin D and parathyroid hormone (PTH) in cardiac remodeling and worsening of HF. Lack of reliable automated testing of 1,25-dihydroxyvitamin D (1,25(OH)2D), the biologically active metabolite of vitamin D, has limited its contribution to the prognostic assessment of HF. Here, the association of 1,25(OH)2D and PTH(1-84) levels was evaluated for prediction of cardiovascular death in chronic HF patients.

METHODS

We conducted a single center prospective cohort including 170 chronic HF patients (females n = 36; males n = 134; NYHA II-IV; mean age: 67 years; etiology: ischemic n = 119, dilated cardiomyopathy n = 51; mean LVEF: 23%). The primary outcome was cardiovascular death.

RESULTS

Serum levels of 1,25(OH)2D decreased markedly with increased HF severity. Medians were 33.3 pg/mL for NYHA-II patients, 23.4 pg/mL for NYHA-III, and 14.0 pg/mL for NYHA-IV patients (p<0.001). Most patients had levels of 25(OH)D below 30ng/mL, and stratification by NYHA functional class did not show significant differences (p = 0.249). The 1,25(OH)2D to PTH(1-84) ratio and the (1,25(OH)2D)2 to PTH(1-84) ratio were found to be the most significantly related to HF severity. After a median follow-up of 4.1 years, 106 out of 170 patients reached the primary endpoint. Cox proportional hazard modeling revealed 1,25(OH)2D and the 1,25(OH)2D to PTH(1-84) ratios to be strongly predictive of outcomes.

CONCLUSIONS

1,25(OH)2D and its ratios to PTH(1-84) strongly and independently predict cardiovascular mortality in chronic HF.

Multiple biomarker strategy based on parathyroid hormone and natriuretic peptides testing for improved prognosis of chronic heart failure

Biomarkers offer new perspectives for a more personalized management of patients with heart failure (HF). Hyperparathyroidism is common in HF patients and parathyroid hormone (PTH) testing might provide added value for the prognostication of HF patients. Our objectives were therefore to determine the efficiency of multiple biomarker strategy based on PTH and natriuretic peptides measurement for the risk stratification of patients with HF. Circulating concentrations of bioactive PTH 1-84 and natriuretic peptides, B-type natriuretic peptide (BNP) and N-terminal proBNP (NT-proBNP), were measured with automated immunoassays in 45 healthy individuals and 137 HF patients with reduced left ventricular ejection fraction. Circulating levels of PTH 1-84 and natriuretic peptides were significantly increased in HF patients in comparison to HF patients. Over a long-term follow-up, baseline PTH 1-84 levels were related to the risk of cardiovascular death. Furthermore, in multiple biomarker approach, PTH measurement was additive to BNP and NT-proBNP testing for the cardiovascular risk assessment of HF patients. In conclusion, the combination of PTH 1-84 and natriuretic peptides testing improves the prognostication of HF patients and might allowed more personalized approach for risk stratification and treatment selection in HF patients.

Interplay of parathyroid hormone and aldosterone antagonist in prevention of heart failure hospitalizations in chronic kidney disease

BACKGROUND

Aldosterone antagonists may mediate their effects on heart failure through parathyroid hormone (PTH) in chronic kidney disease (CKD) patients.

METHODS

Patients with CKD on spironolactone were selected and matched for age, gender, race, use of a vitamin D analogue, the number of antihypertensive medications, and CKD stage. PTH levels before and after the first prescription of spironolactone were measured. A thorough chart review was conducted to assess for heart failure hospitalizations. An adjusted Cox proportional model was used to calculate the hazard ratio (HR) for heart failure hospitalizations among cases versus controls.

RESULTS

There were a total of 950 (mean age 67±13 years, 40% men) patients with CKD. Of these, there were 48 hospitalizations for heart failure among the cases and 82 among the controls (HR 0.37; 95% confidence interval (CI) 0.19-0.74, p=0.005). We noted a more significant decrease in PTH levels among the cases when compared to the controls (p<0.0001). The adjusted hazard for heart failure hospitalization increased with higher PTH levels (p=0.002) and mediation analysis revealed change in PTH level as a significant mediator of heart failure hospitalization (p=0.04).

CONCLUSION

Aldosterone antagonists may be helpful in preventing hospitalizations for heart failure exacerbation in CKD patients through a PTH-mediated effect.

Measurement of Galectin-3 with the ARCHITECT assay: Clinical validity and cost-effectiveness in patients with heart failure

OBJECTIVES

Galectin-3 (Gal-3) testing is emerging as a valuable tool for the prognosis of heart failure (HF). Our objectives were to determine the clinical validity and cost-effectiveness of the recently developed ARCHITECT Gal-3 automated immunoassay.

DESIGN AND METHODS

Gal-3 levels were measured in HF patients with reduced left ventricular ejection fraction with the ARCHITECT i2000SR Gal-3 assay as well as with the reference Gal-3 ELISA assay. The relationship between Gal-3 levels determined with the automated assay and HF severity as well as its predictive value for long-term cardiovascular death were evaluated. The impact of Gal-3 testing on the diagnostic related group (DRG) based reimbursement was also estimated.

RESULTS

Gal-3 levels measured with the ARCHITECT assay were related to the severity of HF based on New York Heart Association functional classes (p<0.001) and were also significantly and positively correlated to BNP concentrations (r=0.35, p<0.001). Gal-3 values higher than 19.2 ng/mL were predictive of long-term cardiovascular death in patients with systolic HF and also provided incremental prognostic information to BNP testing. In addition, Gal-3 testing was estimated to save DRG in comparison to standard of care.

CONCLUSIONS

Our results demonstrated the clinical validity of the ARCHITECT Gal-3 automated immunoassay for the risk stratification of HF patients. The automation of Gal-3 testing was also cost-effective and might help to preserve hospital budget.

PTH: Potential role in management of heart failure

Biomarkers play an important role for the diagnosis and prognosis of heart failure (HF), a disease with high morbidity and mortality as well as a huge impact on healthcare budgets. Parathyroid hormone (PTH) is a major systemic calcium-regulating hormone and an important regulator of bone and mineral homeostasis. PTH testing is important for differential diagnosis of calcemia related disorders and for the management of patients with chronic kidney disease. As secondary hyperparathyroidism has been evidenced in HF patients, PTH testing might be relevant in HF patients for risk stratification and more personalized selection of treatment.

Galectin-3 testing: validity of a novel automated assay in heart failure patients with reduced ejection fraction

Circulating levels of galectin-3 (Gal-3), a marker of cardiac fibrosis and remodeling, contribute to the risk stratification of patients with heart failure (HF). The aim of our study was to determine the analytical validity and clinical validity of a novel automated Gal-3 assay in HF patients with reduced ejection fraction. We showed an excellent agreement between the VIDAS® Gal-3 automated assay and the ELISA reference method (r=0.90, p<0.001) and a mean difference of -1.3 ng/mL was observed on the Bland and Altman plot. Gal-3 levels measured with the VIDAS® assay were significantly related to NYHA functional classes (p<0.001) and mean Gal-3 levels were 13.8 ng/mL in NYHA II patients, 17.7 ng/mL in NYHA III and 19.6 ng/mL in NYHA IV. Furthermore, our results showed that Gal-3 levels measured with the VIDAS® assay were not only predictive of long-term cardiovascular death in patients with systolic HF but have also provided added value to natriuretic peptide testing in multimarker strategies. Therefore, our data are also supporting the clinical validity of the Gal-3 automated assay.