The effects of cinacalcet on blood pressure, mortality and cardiovascular endpoints in the EVOLVE trial

Association of Different Definitions of Intradialytic Hypertension With Long-Term Mortality in Hemodialysis

BACKGROUND

Hypertension is common in hemodialysis patients. A subset of patients experience systolic blood pressure increases from prehemodialysis to posthemodialysis (intradialytic hypertension), which are associated with adverse outcomes. However, little consensus exists on an evidence-based definition.

METHODS

In 3198 hemodialysis patients, Cox models were fit to examine the association of various definitions of intradialytic hypertension (≥30% of baseline sessions with an increase in prehemodialysis to posthemodialysis systolic blood pressure of (1) ≥0 mm Hg [Hyper0]; (2) ≥10 mm Hg [Hyper10], or (3) ≥20 mm Hg increase [Hyper20]) with all-cause mortality. Effect modification was assessed using interaction terms according to prespecified variables.

RESULTS

At baseline, mean age was 62±15 years, 57% were male, and 14% were Black. During the baseline period, 47% of individuals met the Hyper0 definition and experienced 32% (hazard ratio, 1.32 [95% CI, 1.05-1.66]) higher adjusted risk of death, compared with no systolic blood pressure increase. Hyper10 was present in 21.2% and associated with 18% higher adjusted risk of death (hazard ratio, 1.18 [95% CI, 0.94-1.48]). Hyper20 was present in 6.8% and associated with 3% higher adjusted risk of death (hazard ratio 1.03 [95% CI, 0.74-1.44]). Effect modification by age and peripheral vascular disease was observed (P interaction=0.04 for age and 0.02 for peripheral vascular disease), with higher associated risk of death for those aged 45 to 70 years and those without peripheral vascular disease.

CONCLUSIONS

Individuals with any systolic blood pressure increase from prehemodialysis to posthemodialysis had the highest adjusted risk of mortality, compared with other threshold-based definitions.

Atherosclerotic Vascular Disease Associated with Chronic Kidney Disease

Cardiovascular risk increases as glomerular filtration rate (GFR) declines in progressive renal disease and is maximal in patients with end-stage renal disease requiring maintenance dialysis. Atherosclerotic vascular disease, for which hyperlipidemia is the main risk factor and lipid-lowering therapy is the key intervention, is common. However, the pattern of dyslipidemia changes with low GFR and the association with vascular events becomes less clear. While the pathophysiology and management of patients with early chronic kidney disease (CKD) is similar to the general population, advanced and end-stage CKD is characterized by a disproportionate increase in fatal events, ineffectiveness of statin therapy, and greatly increased risk associated with coronary interventions. The most effective strategies to reduce atherosclerotic cardiovascular disease in CKD are to slow the decline in renal function or to restore renal function by transplantation.

Cardiovascular Risk in Patients with Primary Hyperparathyroidism

Primary hyperparathyroidism (PHPT) is one of the most common endocrine disorders characterized by parathyroid hormone (PTH)-dependent hypercalcemia. Cardinal features include low trauma fractures, nephrolithiasis, and chronic kidney disease. Several experimental studies established that parathyroid hormone exerts actions on the cardiovascular (CV) system, including vasodilatation and positive inotropic and chronotropic effects. Observational studies, especially in severe cases, report a higher prevalence of hypertension, diabetes mellitus, lipid abnormalities, endothelial dysfunction, arrhythmias, and left ventricular hypertrophy in patients with PHPT, while the risk of CV events seems to be increased in severe cases. However, the effect of surgery is inconsistent on CV abnormalities and, more importantly, on CV disease (CVD) events, especially in mild cases. In the current review, we describe the available evidence linking PHPT and CVD, as well as the effect of surgical management and pharmacological treatment on CVD manifestations in patients with PHPT. Based on the current evidence, CVD is not considered an indication for surgery.

Fibroblast growth factor 23-Klotho and hypertension: experimental and clinical mechanisms

Hypertension (HTN) and chronic kidney disease (CKD) are increasingly recognized in pediatric patients and represent risk factors for cardiovascular morbidity and mortality later in life. In CKD, enhanced tubular sodium reabsorption is a leading cause of HTN due to augmented extracellular fluid volume expansion. The renin-angiotensin-aldosterone system (RAAS) upregulates various tubular sodium cotransporters that are also targets of the hormone fibroblast growth factor 23 (FGF23) and its co-receptor Klotho. FGF23 inhibits the activation of 1,25-dihydroxyvitamin D that is a potent suppressor of renin biosynthesis. Here we review the complex interactions and disturbances of the FGF23-Klotho axis, vitamin D, and the RAAS relevant to blood pressure regulation and discuss the therapeutic strategies aimed at mitigating their pathophysiologic contributions to HTN.

Secondary Hyperparathyroidism and Hypertension: An Intriguing Couple

: Secondary hyperparathyroidism (SHPTH) is a major complication in patients on maintenance hemodialysis burdened with high cardiovascular risk. Hypertension is also a high prevalence complication contributing to an increase in the mortality rate in hemodialysis patients. A possible association between SHPTH and hypertension has been widely reported in the literature and several pathogenetic mechanisms have been described. There is evidence that the decrease of plasma iPTH levels are correlated with hypertension correction in hemodialysis patients undergoing parathyroidectomy and oral calcimimetics administration. We have observed a similar behaviour also in a patient on chronic hemodialysis treated with Etelcalcetide. Even if this is an isolated observation, it could stimulate future investigation, possibly in dedicated clinical trials.

Treatment Based on Cinacalcet Reduces Oxidative Stress in Hemodialysis Patients with Secondary Hyperparathyroidism

BACKGROUND/AIMS

Oxidative stress is one of the leading factors contributing to increased mortality in patients with chronic kidney disease (CKD) and secondary hyperparathyroidism (sHPT). Cinacalcet is now commonly used in the treatment of sHPT in patients with CKD. The aim of this study was to assess the influence of treatment with cinacalcet on the oxidative stress markers in patients on hemodialysis with sHPT.

METHODS

In 58 hemodialysed patients with sHPT (parathyroid hormone [PTH] > 300 pg/mL) plasma Advanced Oxidation Protein Products (AOPP), serum total antioxidant capacity - ImAnOx (TAS/TAC), serum PTH, calcium and phosphate concentrations were assessed before the first dose of cinacalcet and after 6 months of treatment.

RESULTS

Serum PTH concentration decreased significantly from 895 (748-1,070) to 384 (289-510) pg/mL after 6 months of treatment; p < 0.0001. Mean serum concentrations of -calcium and phosphate remained stable. Plasma AOPP concentration decreased significantly from 152 (126-185) to 49 -(43-57) µmol/L after 6 months of treatment; p < 0.0001. ImAnOx significantly increased from 260 (251-270) to 272 (264-280) µmol/L; p = 0.04. After 6 months of treatment, a significant, positive correlation was found between ImAnOx and the daily dose of cinacalcet (r = 0.30; p = 0.02). Also, the change of serum ImAnOx during treatment with cinacalcet significantly correlated with the daily dose of cinacalcet r = 0.35; p = 0.01. No significant correlations were found between plasma AOPP concentration or ImAnOx and PTH, or their changes in time.

CONCLUSIONS

(1) Six-month treatment based on cinacalcet seems to reduce oxidative stress markers in maintenance hemodialysis patients with sHPT. (2) This benefit may be related rather to the direct action of cinacalcet than to the serum PTH concentration decrease.

Discovery and Development of Calcimimetic and Calcilytic Compounds

The extracellular calcium receptor (CaR) is a G protein-coupled receptor (GPCR) and the pivotal molecule regulating systemic Ca²⁺ homeostasis. The CaR was a challenging target for drug discovery because its physiological ligand is an inorganic ion (Ca²⁺) rather than a molecule so there was no structural template to guide medicinal chemistry. Nonetheless, small molecules targeting this receptor were discovered. Calcimimetics are agonists or positive allosteric modulators of the CaR, while calcilytics are antagonists and all to date are negative allosteric modulators. The calcimimetic cinacalcet was the first allosteric modulator of a GPCR to achieve regulatory approval and is a first-in-class treatment for secondary hyperparathyroidism in patients on dialysis, and for hypercalcemia in some forms of primary hyperparathyroidism. It is also useful in treating some rare genetic diseases that cause hypercalcemia. Two other calcimimetics are now on the market (etelcalcetide) or under regulatory review (evocalcet). Calcilytics stimulate the secretion of parathyroid hormone and were initially developed as treatments for osteoporosis. Three different calcilytics of two different chemotypes failed in clinical trials due to lack of efficacy. Calcilytics are now being repurposed and might be useful in treating hypoparathyroidism and several rare genetic diseases causing hypocalcemia. The challenges ahead for medicinal chemists are to design compounds that select conformations of the CaR that preferentially target a particular signalling pathway and/or that affect the CaR in a tissue-selective manner.

Acute effects of cinacalcet on arterial stiffness and ventricular function in hemodialysis patients: A randomized double-blinded crossover study

BACKGROUND

Serum calcium concentration (Ca) plays an essential role in a vascular muscle tone and myocardial contractility. Previously, we showed that acutely lowering Ca by hemodialysis reduced arterial stiffness. Cinacalcet is a calcimimetic that lowers Ca and parathyroid hormone (PTH). The aim of the present study was to examine whether acute lowering of Ca by cinacalcet improves vascular stiffness and myocardial diastolic dysfunction.

METHOD

This is a double-blinded randomized placebo-controlled crossover study that included 21 adult patients with end-stage kidney disease undergoing chronic hemodialysis. Subjects were assigned to placebo-cinacalcet (30 mg) or cinacalcet-placebo sequence. After each treatment period (7 days), aortic, brachial, and carotid stiffness were determined by examining carotid-femoral pulse wave velocity (cf-PWV), carotid-radial PWV (cr-PWV), and carotid distension. A central pulse wave profile was determined by radial artery tonometry and cardiac function was evaluated by echocardiography.

RESULTS

Cinacalcet reduced PTH (483 [337-748] to 201 [71-498] ng/L, P < .001) and ionized Ca (1.11 [1.08-1.15] to 1.05 [1.00-1.10] mmol/L, P = .04). Cinacalcet did not reduced cf-PWV significantly (12.2 [10.4-15.4] to 12.2 [11.0-14.6] m/s, P = .16). After adjustments for mean blood pressure, sequence, carryover, and treatment effects, cf-PWV was not significantly lowered by cinacalcet (-0.35 m/s, P = .139). There were no significant changes in central blood pressures, brachial and carotid stiffness, and echocardiographic parameters.

CONCLUSION

In this study, 30 mg daily cinacalcet for 1 week did not have any significant impact on peripheral and central blood pressures, arterial stiffness parameters, or cardiac function (NCT01250405).

The Risk of Peripheral Arterial Disease after Parathyroidectomy in Patients with End-Stage Renal Disease

Purpose

The changes of the risk of peripheral arterial disease (PAD) in patients with end-stage renal disease after parathyroidectomy are scant.

Methods

We used a nationwide health insurance claims database to select all dialysis-dependent patients with end-stage renal disease aged 18 years and older for the study population in 2000 to 2006. Of the patients with end-stage renal disease, we selected 947 patients who had undergone parathyroidectomy as the parathyroidectomy group and frequency matched 3746 patients with end-stage renal disease by sex, age, years since the disease diagnosis, and the year of index date as the non-parathyroidectomy group. We used a multivariate Cox proportional hazards regression analysis with the use of a robust sandwich covariance matrix estimate, accounting for the intra-cluster dependence of hospitals or clinics, to measure the risk of peripheral arterial disease for the parathyroidectomy group compared with the non-parathyroidectomy group after adjusting for sex, age, premium-based income, urbanization, and comorbidity.

Results

The mean post-op follow-up periods were 5.08 and 4.52 years for the parathyroidectomy and non-parathyroidectomy groups, respectively; the incidence density rate of PAD in the PTX group was 12.26 per 1000 person-years, significantly lower than the data in the non-PTX group (24.09 per 1000 person-years, adjusted HR = 0.66, 95% CI = 0.46–0.94).

Conclusion

Parathyroidectomy is associated with reduced risk of peripheral arterial disease in patients with end-stage renal disease complicated with severe secondary hyperparathyroidism.