Serum intact parathyroid hormone levels independently predict exercise capacity in stable heart failure patients

Can parathyroid hormone be used as a biomarker for heart failure?

Secondary hyperparathyroidism in heart failure is a consequence of renin-angiotensin-aldosterone activation, chronic hyperaldosteronism, and loop diuretic usage, resulting in calcium excretion. The result is an inflammatory state with adverse effects on myocardial remodeling and systemic complications. Recent literature has suggested that elevated parathyroid hormone predicts adverse outcomes in patients with heart failure independent of serum calcium and phosphate, vitamin D deficiency, and renal insufficiency. Parathyroid hormone has been correlated with elevated brain natriuretic peptide levels, an established biomarker of heart failure severity. There are several limitations to the utilization of parathyroid hormone as a biomarker for heart failure, and further prospective studies need to be conducted to assess the value of multiple parathyroid hormone measurements over time and elucidate the role of parathyroid hormone in diastolic dysfunction. Pending further validation, there is promise for parathyroid hormone as a complementary biomarker in heart failure.

Exercise intolerance in chronic heart failure: the role of cortisol and the catabolic state

Chronic heart failure (CHF) is a complex clinical syndrome leading to exercise intolerance due to muscular fatigue and dyspnea. Hemodynamics fail to explain the reduced exercise capacity, while a significant skeletal muscular pathology seems to constitute the main underlying mechanism for exercise intolerance in CHF patients. There have been proposed several metabolic, neurohormonal and immune system abnormalities leading to an anabolic/catabolic imbalance that plays a central role in the pathogenesis of the wasting process of skeletal muscle myopathy. The impairment of the anabolic axes is associated with the severity of symptoms and the poor outcome in CHF, whereas increased cortisol levels are predictive of exercise intolerance, ventilatory inefficiency and chronotropic incompetence, suggesting a significant contributing mechanism to the limited functional status. Exercise training and device therapy could have beneficial effects in preventing and treating muscle wasting in CHF. However, specific anabolic treatment needs more investigation to prove possible beneficial effects.

Secondary hyperparathyroidism: benign bystander or culpable contributor to adverse health outcomes?

Elevation in serum parathyroid hormone (PTH) often accompanies vitamin D deficiency and renal impairment. PTH elevation in renal failure is viewed as an unfavorable development. Evidence is increasing that PTH elevation may be associated with increased morbidity and mortality. In many instances these PTH effects appear to be independent of vitamin D status. PTH mediates its effects through the ubiquitous type 1 PTH/PTH-related peptide receptor, which is notably present in the cardiovascular system. Increased PTH may promote cardiovascular disease through diminished cardiac contractility, enhanced coronary risk, and cardiac valvular and vascular calcification. High PTH levels appear to be linked to the metabolic syndrome and are aligned with hyperlipidemia, decreased insulin sensitivity, and, perhaps, decreased insulin secretion. Increased PTH also is associated with neuroendocrine activation, increased sympathetic activity, and endothelial stress. The relation between PTH and vitamin D is complex and may show significant threshold variations, especially when calcium intake, age, and race are considered. Moreover, evidence is increasing that fragments of PTH may not only be hormonally active but also may have opposing effects to PTH. Despite these caveats, PTH values provide useful clinical diagnostic and prognostic information in monitoring many chronic ailments such as heart and renal failure and multiple sclerosis.