Structural, functional and autonomic changes in the cardiovascular system in growth hormone deficient patients

Effects of human recombinant growth hormone on exercise capacity, cardiac structure, and cardiac function in patients with adult-onset growth hormone deficiency

Objective

Epidemiological studies suggest that adult-onset growth hormone deficiency (AGHD) might increase the risk of death from cardiovascular causes.

Methods

This was a 6-month double-blind, placebo-controlled, randomised, cross-over trial followed by a 6-month open-label phase. Seventeen patients with AGHD received either recombinant human growth hormone (rGH) (0.4 mg injection daily) or placebo for 12 weeks, underwent washout for 2 weeks, and were then crossed over to the alternative treatment for a further 12 weeks. Cardiac magnetic resonance imaging, echocardiography, and cardiopulmonary exercise testing were performed at baseline, 12 weeks, 26 weeks, and the end of the open phase (12 months). The results were compared with those of 16 age- and sex-matched control subjects.

Results

At baseline, patients with AGHD had a significantly higher systolic blood pressure, ejection fraction, and left ventricular mass than the control group, even when corrected for body surface area. Treatment with rGH normalised the insulin-like growth factor 1 concentration without an effect on exercise capacity, cardiac structure, or cardiac function.

Conclusion

Administration of rGH therapy for 6 to 9 months failed to normalise the functional and structural cardiac differences observed in patients with AGHD when compared with a control group.

CARDIAC STRUCTURAL AND FUNCTIONAL ABNORMALITIES IN FEMALES WITH UNTREATED HYPOPITUITARISM DUE TO SHEEHAN SYNDROME: RESPONSE TO HORMONE REPLACEMENT THERAPY

OBJECTIVE

Data on cardiac abnormalities in females with untreated hypopituitarism are limited. We investigated echocardiographic abnormalities in females with untreated hypopituitarism and their response to treatment.

METHODS

Twenty-three females with treatment-naïve hypopituitarism and 30 matched healthy controls were evaluated for cardiac structure and function. Echocardiographic evaluation was done at presentation and after achieving a euthyroid and eucortisol state.

RESULTS

Fourteen (61%) patients had mitral regurgitation, and 11 (48%) had pericardial effusion as against none among controls. Indices of left ventricular (LV) size like LV end diastolic dimension (LVEDD; 44.5 ± 3.5 mm in cases vs. 47.6 ± 3.8 mm in controls, P = .004), and LV diastolic volume (LVEDV; 91.8 ± 18.0 mL versus 106.5 ± 20.4 mL, P = .009) were significantly lower in the SS group compared with controls. LV mass (LVM) was 70.8 ± 19.2 g in cases and 108.0 ± 33.2 g in controls (P = .02). Similarly, indices of LV systolic function like stroke volume (SV; 59.1 ± 12.0 mL in cases and 74.4 ± 15.8 mL in controls; P = .000), ejection fraction (EF; 64.3 ± 6.2 % in cases against 69.9 ± 9.2 % in controls; P = .03), and fractional shortening (FS; 34.9 ± 4.7% versus 40.1 ± 4.4%, P = .000) were significantly decreased in patients compared with controls. Cardiac abnormalities normalized with restoration of a euthyroid and eucortisol state.

CONCLUSION

Pericardial effusion, mitral regurgitation, and diminished LVM are common in females with untreated hypopituitarism.

ABBREVIATIONS

ACTH = adrenocorticotrophic hormone BMI = body mass index DT = deceleration time EDV = end-diastolic volume EF = ejection fraction FS = fractional shortening GH = growth hormone IGF-1 = insulin growth factor-1 ITT = insulin tolerance test IVSd = interventricular septal diameter LH = luteinizing hormone LV = left ventricular LVEDD = LV end diastolic dimension LVEDV = LV end diastolic volume LVM = LV mass MRI = magnetic resonance imaging MVP = mitral value prolapse PPH = postpartum hemorrhage PWd = posterior wall diameter SS = Sheehan syndrome SV = stroke volume T3 = triiodothyronine T4 = thyroxine TSH = thyroid-stimulating hormone.

Cardiac function in growth hormone deficient patients before and after 1 year with replacement therapy: a magnetic resonance imaging study

Assessed by conventional echocardiography the influence of growth hormone deficiency (GHD) and effects of replacement therapy on left ventricle (LV) function and mass (LVM) have shown inconsistent results. We aimed to evaluate cardiac function before and during replacement therapy employing the gold standard method cardiac magnetic resonance imaging (CMRI) and measurements of circulating levels of B-type natriuretic peptides. Sixteen patients (8 males and 8 females, mean age 49 years (range 18-75)) with severe GHD and 16 matched control subjects were included. CMRI was performed at baseline and after 1 year of GH replacement therapy. IGF-I, B-type natriuretic peptide (BNP) and N-terminal pro-BNP (NT-proBNP) were measured after 0, 1, 2, 3, 6 and 12 months of treatment. IGF-I Z-score increased from (median (IQR)) -2.3 (-3.8 to -1.4) to 0.5 (-0.3 to 1.7). LVM index (LVMI), ejection fraction (range 63-80%), cardiac output index and levels of BNP and NT-proBNP were similar at baseline in patients compared to controls (P-values from 0.09 to 0.37). The patients had significantly smaller LV end-diastolic volume index (P = 0.032) and end-systolic volume index (P = 0.038). No significant change in LV systolic function or LVM occurred during 1 year of GH treatment. BNP levels were unchanged (P = 0.88), whereas NT-proBNP tended to decrease (P = 0.052). Assessed by the highly sensitive and precise CMRI method, untreated GHD was not associated with impaired systolic function or reduced LVMI and 1 year of GH replacement using physiological doses did not influence cardiac mass or function.

The effects of 12 months of growth hormone replacement therapy on cardiac autonomic tone in adults with growth hormone deficiency

OBJECTIVES

Growth hormone deficiency (GHD) in adults is associated with a cluster of cardiovascular risk factors. Some abnormalities of cardiac structure and function have been reported in adult patients with GHD, but there are few data related to cardiac autonomic tone. Non-invasive assessment of cardiac autonomic status can be achieved by heart rate variability (HRV), which can be measured by using time-domain or frequency-domain variables. To our knowledge, short-term (6 months) effects of GH replacement therapy (GHRT) on HRV in a limited number of patients have been evaluated prospectively in only two previous studies. The present study was therefore designed to investigate the effects of GHD and 12 months of GHRT on cardiac autonomic tone in a larger number of adult patients with severe GHD.

PATIENTS AND METHODS

HRV measurement, by using time-domain variables, was performed in 22 patients with GHD (eight men, 14 women; mean age 45.4 +/- 2.4 years) and 22 healthy controls (nine men, 13 women; mean age 40.8 +/- 1.8 years) at baseline. The time-domain variables (sympathetically influenced parameters SDNN and SDANN and parasympathetically influenced parameters RMSSD and PNN50) were derived from 24-h electrocardiogram (ECG) recordings. In the patient group, cardiac autonomic tone was re-evaluated after 6 and 12 months of GHRT.

RESULTS

Mean baseline values of SDNN and SDANN were significantly higher (higher values mean lower sympathetic activity) in GHD patients than in healthy controls (P < 0.05), but mean baseline values of RMSSD and PNN50 did not differ significantly in healthy controls and patients. After 6 and 12 months of GHRT, mean SDNN and SDANN were decreased significantly when compared with the baseline values before GHRT (P < 0.05). However, mean RMSSD and PNN50 did not differ significantly from baseline. When SDNN and SDANN measurements were evaluated individually for each patient, after 12 months of GHRT both of the sympathetically influenced parameters decreased in 90% of the patients.

CONCLUSIONS

These data indicate that sympathetic tone is decreased in adult patients with severe GHD. Additionally, an increment in sympathetic activity and normalization of sympathovagal balance have been demonstrated after 6 and 12 months of GHRT. This result suggests that, at least at the doses used in this study, GHRT improves sympathetic tone, without an obvious arrhythmogenic effect.