Growth Hormone Therapy in Heart Failure: Where Are We Now?

Catherine Demers, MD, MSc, Robert S. McKelvie, MD, PhD

Disclosures

CHF. 2003;9(2) 

In This Article

Conclusion

Results from small, nonrandomized studies have demonstrated improvements in cardiac chamber dimensions, cardiac function, quality of life, and functional capacity in patients with mild to moderate symptoms of HF. Although these data are encouraging, results from short-term, randomized, placebo-controlled trials did not confirm the earlier reports of significant benefits on cardiovascular function from uncontrolled studies. However, the randomized, controlled studies were underpowered to detect significant differences in cardiac function, hemodynamic parameters, and functional capacity. The duration of treatment and dosage regimen of rhGH in patients with HF may also partially explain the lack of effectiveness seen in these three randomized clinical trials. The current level of evidence for GH replacement in HF does not support the use of GH as adjuvant therapy.

GH and IGF-I are clearly important in maintaining normal structure and function of the heart. GH may potentially be beneficial in HF patients by increasing left ventricular mass, decreasing left ventricular wall stress, and affecting left ventricular remodeling. GH may further unload the ventricle through left ventricular geometric changes combined with a reduction in peripheral vascular resistance. Compared to other inotropic treatments tested in HF patients, GH may potentially increase contractility and act on peripheral resistance without causing activation of the sympathetic nervous system. Additional benefit may be mediated through an increase in skeletal muscle mass and improvement of strength. In contrast, supraphysiologic levels of GH for prolonged durations, seen in acromegaly, are associated with left ventricular hypertrophy, hypertension, and congestive heart failure, all of which are associated with increased mortality. The administration of high doses of GH to critically ill patients in the intensive care unit setting has also been associated with increased mortality, prolonged intensive care unit stay, increased length of hospitalization, and increased duration of mechanical ventilation.[52] As there is only a small amount of data currently available on the therapeutic use of GH in patients with HF, further dose-ranging studies of longer duration are needed to elucidate the role of GH therapy in addition to standard therapy in improving cardiac function, functional capacity, and survival of HF patients.

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