Acromegaly and cardiovascular disorders. A prospective study

ECHOCARDIOGRAPHIC MYOCARDIAL CHANGES IN ACROMEGALY: A CROSS-SECTIONAL ANALYSIS IN A TERTIARY CENTER IN BULGARIA

Context

Cardiomyopathy is the most frequent cardiovascular complication in acromegaly.

Objective

We aimed to compare some echocardiographic markers in acromegaly patients with controls and find a correlation with disease duration, disease activity, levels of growth hormone (GH) and insulin-like growth factor 1 (IGF-1).

Design

We conducted a cross-sectional case-control study for the period of 2008-2012.

Subjects and methods

Acromegaly patients altogether 146 (56 men and 90 women), were divided into four groups according to disease activity and the presence of arterial hypertension (AH). The control group included 83 subjects, matching the patient groups by age, gender and presence of AH. GH was measured by an immunofluorometric method, while IGF-1 by IRMA method. All patients and controls were subjected to one- and two-dimensional transthoracic echocardiography, color and pulse Doppler.

Results

We found a thickening of the left ventricular walls and an increase in the left ventricular mass. However, these changes were not statistically significant in all groups and no correlation with disease duration could be demonstrated. As markers of diastolic dysfunction, increased deceleration time and isovolumetric relaxation were registered, which were dependent mainly on age in a binary logistic regression analysis, but not GH or IGF-1. Using absolute values, ejection and shortening fractions were increased in some groups. Using cut-off values, a higher percentage of systolic dysfunction was demonstrated in patients compared to their corresponding controls. Engagement of the right heart ventricle was also found - increased deceleration time and decreased e/a tric ratio.

Conclusions

In conclusion, functional impairments of both ventricles were present, with a predominance of left ventricular diastolic dysfunction.

Time spent with cats is never wasted: Lessons learned from feline acromegalic cardiomyopathy, a naturally occurring animal model of the human disease

BACKGROUND

In humans, acromegaly due to a pituitary somatotrophic adenoma is a recognized cause of increased left ventricular (LV) mass. Acromegalic cardiomyopathy is incompletely understood, and represents a major cause of morbidity and mortality. We describe the clinical, echocardiographic and histopathologic features of naturally occurring feline acromegalic cardiomyopathy, an emerging disease among domestic cats.

METHODS

Cats with confirmed hypersomatotropism (IGF-1>1000ng/ml and pituitary mass; n = 67) were prospectively recruited, as were two control groups: diabetics (IGF-1<800ng/ml; n = 24) and healthy cats without known endocrinopathy or cardiovascular disease (n = 16). Echocardiography was performed in all cases, including after hypersomatotropism treatment where applicable. Additionally, tissue samples from deceased cats with hypersomatotropism, hypertrophic cardiomyopathy and age-matched controls (n = 21 each) were collected and systematically histopathologically reviewed and compared.

RESULTS

By echocardiography, cats with hypersomatotropism had a greater maximum LV wall thickness (6.5mm, 4.1-10.1mm) than diabetic (5.9mm, 4.2-9.1mm; Mann Whitney, p<0.001) or control cats (5.2mm, 4.1-6.5mm; Mann Whitney, p<0.001). Left atrial diameter was also greater in cats with hypersomatotropism (16.6mm, 13.0-29.5mm) than in diabetic (15.4mm, 11.2-20.3mm; Mann Whitney, p<0.001) and control cats (14.0mm, 12.6-17.4mm; Mann Whitney, p<0.001). After hypophysectomy and normalization of IGF-1 concentration (n = 20), echocardiographic changes proved mostly reversible. As in humans, histopathology of the feline acromegalic heart was dominated by myocyte hypertrophy with interstitial fibrosis and minimal myofiber disarray.

CONCLUSIONS

These results demonstrate cats could be considered a naturally occurring model of acromegalic cardiomyopathy, and as such help elucidate mechanisms driving cardiovascular remodeling in this disease.

Time spent with cats is never wasted: Lessons learned from feline acromegalic cardiomyopathy, a naturally occurring animal model of the human disease

Background

In humans, acromegaly due to a pituitary somatotrophic adenoma is a recognized cause of increased left ventricular (LV) mass. Acromegalic cardiomyopathy is incompletely understood, and represents a major cause of morbidity and mortality. We describe the clinical, echocardiographic and histopathologic features of naturally occurring feline acromegalic cardiomyopathy, an emerging disease among domestic cats.

Methods

Cats with confirmed hypersomatotropism (IGF-1>1000ng/ml and pituitary mass; n = 67) were prospectively recruited, as were two control groups: diabetics (IGF-1<800ng/ml; n = 24) and healthy cats without known endocrinopathy or cardiovascular disease (n = 16). Echocardiography was performed in all cases, including after hypersomatotropism treatment where applicable. Additionally, tissue samples from deceased cats with hypersomatotropism, hypertrophic cardiomyopathy and age-matched controls (n = 21 each) were collected and systematically histopathologically reviewed and compared.

Results

By echocardiography, cats with hypersomatotropism had a greater maximum LV wall thickness (6.5mm, 4.1–10.1mm) than diabetic (5.9mm, 4.2–9.1mm; Mann Whitney, p<0.001) or control cats (5.2mm, 4.1–6.5mm; Mann Whitney, p<0.001). Left atrial diameter was also greater in cats with hypersomatotropism (16.6mm, 13.0–29.5mm) than in diabetic (15.4mm, 11.2–20.3mm; Mann Whitney, p<0.001) and control cats (14.0mm, 12.6–17.4mm; Mann Whitney, p<0.001). After hypophysectomy and normalization of IGF-1 concentration (n = 20), echocardiographic changes proved mostly reversible. As in humans, histopathology of the feline acromegalic heart was dominated by myocyte hypertrophy with interstitial fibrosis and minimal myofiber disarray.

Conclusions

These results demonstrate cats could be considered a naturally occurring model of acromegalic cardiomyopathy, and as such help elucidate mechanisms driving cardiovascular remodeling in this disease.

Characterisation of myocardial structure and function in adult-onset growth hormone deficiency using cardiac magnetic resonance

Growth hormone (GH) can profoundly influence cardiac function. While GH excess causes well-defined cardiac pathology, fewer data are available regarding the more subtle cardiac changes seen in GH deficiency (GHD). This preliminary study uses cardiac magnetic resonance imaging (CMR) to assess myocardial structure and function in GHD. Ten adult-onset GHD patients underwent CMR, before and after 6 and 12 months of GH replacement. They were compared to 10 age-matched healthy controls and sex-matched healthy controls. Left ventricular (LV) mass index (LVMi) increased with 1 year of GH replacement (53.8 vs. 57.0 vs. 57.3 g/m², analysis of variance p = 0.0229). Compared to controls, patients showed a trend towards reduced LVMi at baseline (51.4 vs. 60.0 g/m², p = 0.0615); this difference was lost by 1 year of GH treatment (57.3 vs. 59.9 g/m², p = 0.666). Significantly reduced aortic area was observed in GHD (13.2 vs. 19.0 cm²/m², p = 0.001). This did not change with GH treatment. There were no differences in other LV parameters including end-diastolic volume index (EDVi), end-systolic volume index, stroke volume index (SVi), cardiac index and ejection fraction. There was a trend towards reduced baseline right ventricular (RV)SVi (44.1 vs. 49.1 ml/m², p = 0.0793) and increased RVEDVi over 1 year (70.3 vs. 74.3 vs. 73.8 ml/m², p = 0.062). Two patients demonstrated interstitial expansion, for example with fibrosis, and three myocardial ischaemia as assessed by late gadolinium enhancement and stress perfusion. The increased sensitivity of CMR to subtle cardiac changes demonstrates that adult-onset GHD patients have reduced aortic area and LVMi increases after 1 year of GH treatment. These early data should be studied in larger studies in the future.

Associations of coefficient of variation of serum GH with previous radiotherapy, hypopituitarism and cardiac disease in patients with treated acromegaly

BACKGROUND

Cardiovascular complications represent the biggest cause of mortality in acromegaly. It is therefore important to optimally stratify acromegalic patients according to disease activity and complication risk. GH is secreted in a pulsatile manner from the pituitary gland, but GH pulsatility is not routinely assessed clinically. The coefficient of variation of serum GH (GHCV) during oral glucose tolerance test (OGTT) quantifies the variation of GH secretion in patients with acromegaly, but has not been reported previously.

AIM

To investigate whether GHCV during OGTT is associated with clinical parameters predicted to relate with hypothalamo-pituitary dysfunction during acromegaly, such as radiotherapy treatment, pituitary deficiency and cardiac disease.

METHODS

GHCV was calculated during 584 OGTTs and compared with nadir serum GH and IGF-1 in 111 acromegalic patients treated at a single centre.

RESULTS

Acromegalic patients treated with radiotherapy had a 37% lower level of GHCV when compared to the nonradiotherapy group (mean GHCV: 0·298 ± 0·015, no radiotherapy; 0·189 ± 0·007, radiotherapy; P < 0·001). Neither serum IGF-1 nor nadir GH was significantly altered in the radiotherapy group. Mean GHCV was 50% lower in the acromegalic patients with cardiac failure when compared to acromegalic patients with normal echocardiogram (0·161 ± 0·034 vs 0·297 ± 0·055; P < 0·05). Neither serum IGF-1 nor nadir GH was significantly altered during cardiac failure.

CONCLUSION

Our preliminary data suggest that GHCV during OGTT may be reduced during acromegaly in patients with previous radiotherapy, pituitary deficiencies and cardiac disease. Larger studies are required to determine whether GHCV could provide help to assess the morbidity status of patients with treated acromegaly.

Congestive heart failure in acromegaly: A review of 6 cases

BACKGROUND

Though cardiac involvement is common in acromegaly, overt congestive heart failure is uncommon.

MATERIALS AND METHODS

This is retrospective analysis of hospital record between 1996 and 2007. We analyzed records of 150 consecutive patients with acromegaly. We included the patients with acromegaly those who had overt congestive heart failure either at presentation or during the course of illness for the present analysis. The diagnosis of acromegaly and congestive cardiac failure were based on standard criteria.

RESULTS

Out of 150 patients with acromegaly, 6 patients had overt CHF (4.0%), of which 4 presented with the features of CHF and 2 developed during the course of illness. Three patients had hypertension and 1 had diabetes. Baseline echocardiography showed severe biventricular dysfunction and global hypokinesia in all. Angiography showed dilated hypokinetic left ventricle with normal coronaries in 3, it was confirmed at autopsy in 1. Three underwent trans-sphenoidal surgery, 1 received somatostatin analogue as primary treatment modality. Normalization of growth hormone and IGF-1 led to improvement in cardiac function in 1, 1 patient lost to follow up, and 4 died during the course of illness. In 1 patient, autopsy was performed and cardiac specimen revealed normal coronaries, concentric ventricular hypertrophy, and dilatation with myofibrolysis and interfascicular fibrosis.

CONCLUSION

Prevalence of overt CHF is 4% in present series. Overt CHF carries poor prognosis and hence, this complication should be recognized at earliest, and medical management to normalized cardiac function should be given utmost priority.

Growth hormone and the cardiovascular system

Growth hormone (GH) exerts its effects through insulin-like growth factor-1, and although ubiquitous in human tissues, it has a significant role in cardiovascular function. In recent years, there has been a great deal of interest in GH as an etiologic factor in many cardiovascular disease states. Acromegaly, a state of endogenous GH excess, results in myocardial hypertrophy and decreased cardiac performance with increased cardiovascular mortality. Additional insight into the role of excess GH on the cardiovascular system has been gained from data collected in athletes doping with GH. Likewise, GH deficiency is associated with increased mortality, possibly from the associated increase in atherosclerosis, lipid abnormalities, and endothelial dysfunction. However, further research is required to clarify the benefit of GH treatment in both deficient states and in heart failure patients.

McCune-Albright syndrome and the extraskeletal manifestations of fibrous dysplasia

Fibrous dysplasia (FD) is sometimes accompanied by extraskeletal manifestations that can include any combination of café-au-lait macules, hyperfunctioning endocrinopathies, such as gonadotropin-independent precocious puberty, hyperthyroidism, growth hormone excess, FGF23-mediated renal phosphate wasting, and/or Cushing syndrome, as well as other less common features. The combination of any of these findings, with or without FD, is known as McCune-Albright syndrome (MAS). The broad spectrum of involved tissues and the unpredictable combination of findings owe to the fact that molecular defect is due to dominant activating mutations in the widely expressed signaling protein, Gsα, and the fact these mutations arises sporadically, often times early in development, prior to gastrulation, and can distribute across many or few tissues.The complexity can be mastered by a systematic screening of potentially involved tissues and cognizance that the pattern of involved tissues is established, to some degree, in utero. Thorough testing allows the clinician to establish, often times at presentation, the full extent of the disease, and importantly as well what tissues are unaffected. Treatment and follow-up can then be focused on affected systems and a meaningful prognosis can be offered to the patient and family. The authors outline screening and treatment strategies that allow for effective management of the extraskeletal manifestations of FD.

A hyperkinetic heart in uncomplicated active acromegaly. Explanation of hypertension in acromegalic patients?

Cardiac function was studied by echocardiography in 12 patients with active acromegaly and in 12 age- and sex-matched healthy control subjects. None of the patients had cardiovascular diseases or other endocrine diseases than acromegaly. The patients had a mean age of 39 +/- 5 years and were short-term acromegalic with a mean duration of disease of 6 +/- 3 years. Mean left ventricular mass was 163 +/- 43 g/m2 in the acromegalic group versus 120 +/- 24 g/m2 in the control group. Preload (the diastolic diameter of the left ventricle) was within normal limits, while afterload (end-systolic meridional wall stress) was significantly decreased in the acromegalic group. Myocardial contractility assessed as fractional shortening of the left ventricle was 39.9 +/- 3.6% in the acromegalic group versus 32.9 +/- 5.1% in the control group, and cardiac output was increased by 52% in the acromegalic group because of increased heart rate and stroke volume. We suggest that augmented peripheral blood flow is responsible for the condition of cardiac hyperkinesia in short-term acromegaly and involved in the development of hypertension, which is a frequent complication of long-term acromegaly.

Amelioration of cardiovascular risk factors with partial biochemical control of acromegaly

OBJECTIVE

Complete remission of acromegaly is associated with favourable changes in cardiovascular risk parameters. We evaluated the effects of suboptimal therapy on haemodynamic, metabolic, inflammatory and coagulation cardiovascular risk indices.

DESIGN AND METHODS

Eighteen acromegalic patients on somatostatin analogues, with incomplete biochemical control, were evaluated at diagnosis and 6 months after treatment and compared to 15 healthy age- and body mass index (BMI)-matched controls. Measurements of blood pressure, GH, IGF-I, glucose, insulin, glycated haemoglobin (HbA1c), lipids, apolipoprotein A1 (apoA1), apoB, high-sensitivity C-reactive protein (hs-CRP), fibrinogen, plasminogen activator inhibitor 1 (PAI-1), tissue plasminogen activator (tPA) and circulating thrombomodulin were performed in all study participants, followed by an oral glucose tolerance test (OGTT). Insulin sensitivity (IS) was expressed by the Matsuda index (OGTT(ISI)).

RESULTS

Partial control of acromegaly resulted in a significant reduction in systolic and diastolic blood pressure, glucose, insulin, HbA1c, total (T-C) and low density lipoprotein cholesterol (LDL-C) and triglyceride levels, and a significant increase in apoA1, high density lipoprotein cholesterol (HDL-C) and OGTT(ISI) compared to pretreatment levels. Plasma fibrinogen and PAI-1 levels fell significantly [respectively (mean +/- SEM), 11.04 +/- 0.41 vs. 10.12 +/- 0.34 micromol/l, P = 0.003 and 9.6 +/- 1.97 vs. 6.55 +/- 1.89 microg/l, P < 0.001]. However, a marked reduction in tPA [median (IQR) 5.1 (2.5-15) vs. 3.4 (2.4-8.6) microg/l, P = 0.031] and an increase in hs-CRP [median (IQR) 0.05 (0.03-0.11) vs. 0.1 (0.06-0.23) mg/l, P < 0.001] were also noted. On treatment, acromegalic patients were comparable to controls, except for OGTT(ISI), lipoprotein(a) [Lp(a)], fibrinogen and tPA and HDL-C levels. Thrombomodulin and apoB levels were not affected by treatment.

CONCLUSIONS

Partial control in disease activity following somatostatin analogues results in significant improvement in a considerable number of cardiovascular risk markers in acromegaly.

Growth hormone and heart failure: oxidative stress and energetic metabolism in rats

Several evidences point for beneficial effects of growth hormone (GH) in heart failure (HF). Taking into account that HF is related with changes in myocardial oxidative stress and in energy generation from metabolic pathways, it is important to clarify whether GH increase or decrease myocardial oxidative stress and what is its effect on energetic metabolism in HF condition. Thus, this study investigated the effects of two different doses of GH on energetic metabolism and oxidative stress in myocardium of rats with HF. Male Wistar rats (n=25) were submitted to aortic stenosis (AS). The HF was evidenced by tachypnea and echocardiographic criteria around 28 weeks of AS. The rats were then randomly divided into three groups: (HF) with HF, treated with saline (0.9% NaCl); (HF-GH1), treated with 1 mk/kg/day recombinant human growth hormone (rhGH), and (HF-GH2) treated with 2 mg/kg/day rhGH. GH was injected, subcutaneously, daily for 2 weeks. A control group (sham; n=12), with the same age of the others rats was evaluated to confirm data for AS. HF had lower IGF-I (insulin-like growth factor-I) than sham-operated rats, and both GH treatments normalized IGF-I level. HF-GH1 animals had lower lipid hydroperoxide (LH), LH/total antioxidant substances (TAS) and glutathione-reductase than HF. Glutathione peroxidase (GSH-Px), hydroxyacyl coenzyme-A dehydrogenase, lactate dehydrogenase(LDH) were higher in HF-GH1 than in HF. HF-GH2 compared with HF, had increased LH/TAS ratio, as well as decreased oxidized glutathione and LDH activity. Comparing the two GH doses, GSH-Px, superoxide dismutase and LDH were lower in HF-GH2 than in HF-GH1. In conclusion, GH effects were dose-dependent and both tested doses did not aggravate the heart dysfunction. The higher GH dose, 2 mg/kg exerted detrimental effects related to energy metabolism and oxidative stress. The lower dose, 1mg/kg GH exerted beneficial effects enhancing antioxidant defences, reducing oxidative stress and improving energy generation in myocardium of rats with heart failure.

A case and review of acromegaly-induced cardiomyopathy and the relationship between growth hormone and heart failure: cause or cure or neither or both?

Growth hormone plays an integral role in the development and maintenance of structure and function of the heart. Specific involvement of the heart in acromegaly is termed acromegalic cardiomyopathy, manifested as concentric left ventricular hypertrophy and diastolic dys-function. Left untreated, it ultimately progresses to systolic heart failure. Heart failure from acromegalic cardiomyopathy is one of the most common causes of death in acromegaly. Current treatment options include different approaches to lower elevated growth hormone levels with improvement in symptoms, exercise tolerance, and echocardiographic improvement in regression of left ventricular hypertrophy and indices of diastolic dysfunction. On the other hand, growth hormone is essential for cardiac growth and function and exerts beneficial and protective effects on the cardiovascular system. Its potential role as adjunctive therapy in the treatment of heart failure as derived from experimental studies and clinical trials is discussed.

Effects of growth hormone and insulin-like growth factor-1 on cardiac hypertrophy of hypertensive patients

OBJECTIVES

Growth hormone (GH) and insulin-like growth factor-1 (IGF-1) interfere with cardiac mass (left ventricular mass; LVM) development. We investigated the role of the GH/IGF-1 axis on LVM and ventricular geometry in a group of 230 never-treated hypertensive patients.

METHODS

Partition values for left ventricular hypertrophy (LVH) were 125 g/m2 for both women and men. Insulin resistance was estimated by the homeostasis model assessment (HOMA) index.

RESULTS

A significant inverse correlation was observed between IGF-1 and both fasting insulin (r = -0.249; P < 0.0001) and GH (r = -0.218; P < 0.0001). Systolic blood pressure (157.3 +/- 13.6 versus 149.4 +/- 12.8 mmHg; P < 0.001), fasting insulin (17.4 +/- 8.5 versus 11.4 +/- 6.0 microU/l; P < 0.0001), HOMA (4.4 +/- 2.3 versus 2.9 +/- 1.6; P < 0.0001) and GH (1.0 +/- 1.0 versus 0.4 +/- 0.5 ng/ml; P < 0.0001) were significantly higher in patients with LVH; on the contrary, IGF-1 values (119.1 +/- 47.8 versus 160.1 +/- 75.5 ng/ml; P < 0.0001) were higher in patients without LVH. In a logistic regression analysis, the strongest independent predictors of LVH were GH [relative risk (RR) = 2.078; 95% confidence interval (CI) = 1.364-3.163], HOMA (RR = 1.345; 95% CI = 1.133-1.596), IGF-1 (RR = 0.993; 95% CI = 0.998-0.999) and systolic blood pressure (RR = 1.036; 95% CI = 1.013-1.060). IGF-1 showed an opposite trend in patients with eccentric and concentric hypertrophy.

CONCLUSIONS

Present data demonstrate that the increase in LVM prevalent in human essential hypertension is directly associated with serum GH levels and inversely related to circulating IGF-1.

Anaesthesia for pituitary surgery

The anaesthetic care of patients undergoing pituitary surgery involves an understanding of the varied presentations of pituitary disease and their implications for the patient's perioperative condition and management. The neuroanaesthetist must also have an appreciation of the issues relevant to the surgical approach (either transsphenoidal or, less commonly, transcranial) and be able to anticipate and manage them accordingly.

Pulsed tissue Doppler identifies subclinical myocardial biventricular dysfunction in active acromegaly

OBJECTIVE

The aim of this study was to assess the role of pulsed tissue Doppler (TD) to identify left (LV) and right ventricular (RV) myocardial regional involvement in acromegaly.

PATIENTS AND MEASUREMENTS

Thirty active acromegaly patients, free of diabetes mellitus, thyroid dysfunction, valvular and coronary heart disease, clinically overt heart failure, and 30 sex- and age-matched healthy controls underwent standard Doppler echocardiography and pulsed TD, by placing the sample volume at the level of basal posterior septum, LV lateral mitral annulus and RV lateral tricuspid annulus. Myocardial systolic (S(m)) and diastolic velocities (E(m)/A(m) ratio) and time-intervals of relaxation (RT(m)), precontraction (PCT(m)) and contraction (CT(m)) and the PCT(m)/CT(m) ratio were measured at each level.

RESULTS

The two groups had similar heart rate, whereas acromegaly patients had higher body mass index, systolic and diastolic blood pressure, LV mass and impaired Doppler indexes of LV and RV diastolic function, without any difference in the global systolic function. At TD, acromegaly patients showed significantly delayed RT(m) and PCT(m,) reduced E(m)/A(m), S(m) and increased PCT(m)/CT(m) of posterior septum, mitral annulus and tricuspid annulus in comparison with controls. By separate multilinear regression analyses, after adjusting for body mass index, heart rate, diastolic blood pressure and LV mass index, age was the main independent determinant of tissue Doppler diastolic but not of systolic indexes.

CONCLUSIONS

In active acromegaly, pulsed TD confirms LV and RV diastolic abnormalities detectable by standard Doppler, additionally identifying subclinical biventricular impairment of systolic function.

Gene expression profile in the heart of spontaneous dwarf rat: In vivo effects of growth hormone

Excess and deficit of growth hormone (GH) both affect cardiac architecture as well as its function. To date, experimental and clinical studies have reported that GH has an inotropic effect on animal and human heart, however, it remains controversial whether GH is applicable to the treatment for the patients with chronic heart failure. Also, the mechanism by which GH exerts these biological effects on the heart is not well understood. In this study, we attempted to specify the genes regulated by GH in the heart of spontaneous dwarf rat using a microarray analysis. We found that soluble forms of guanylate cyclase, cofilin1, and thymosin beta4 mRNA were up-regulated in the heart by GH treatment. On the other hand, acyl-CoA synthetase, aldosterone receptor, myosin regulatory light chain, troponin T, laminA, and beta-actin mRNA were down-regulated. These results suggest GH regulates essential molecules that regulate structural, contractile, remodeling, and regenerative functions. Collectively, our data indicate a new integrative understanding for the biological effects of GH on cardiac function.

Cerebrovascular disease in patients with pituitary tumors

Several studies have shown that patients with acromegaly have increased mortality rates for cardiovascular disease and cerebrovascular disease (CVD). Similar associations have also been seen for patients with hypopituitarism or with non-functional pituitary adenomas. This review summarizes these data and discusses the relative importance of different risk factors for cardiovascular, especially CVD, mortality among patients with acromegaly or non-functional pituitary adenomas, and for those with hypopituitarism as a result of other causes.

Systemic complications of acromegaly: epidemiology, pathogenesis, and management

This review focuses on the systemic complications of acromegaly. Mortality in this disease is increased mostly because of cardiovascular and respiratory diseases, although currently neoplastic complications have been questioned as a relevant cause of increased risk of death. Biventricular hypertrophy, occurring independently of hypertension and metabolic complications, is the most frequent cardiac complication. Diastolic and systolic dysfunction develops along with disease duration; and other cardiac disorders, such as arrhythmias, valve disease, hypertension, atherosclerosis, and endothelial dysfunction, are also common in acromegaly. Control of acromegaly by surgery or pharmacotherapy, especially somatostatin analogs, improves cardiovascular morbidity. Respiratory disorders, sleep apnea, and ventilatory dysfunction are also important contributors in increasing mortality and are advantageously benefitted by controlling GH and IGF-I hypersecretion. An increased risk of colonic polyps, which more frequently recur in patients not controlled after treatment, has been reported by several independent investigations, although malignancies in other organs have also been described, but less convincingly than at the gastrointestinal level. Finally, the most important cause of morbidity and functional disability of the disease is arthropathy, which can be reversed at an initial stage, but not if the disease is left untreated for several years.

Cardiac Abnormalities in Acromegaly

Cardiovascular disease is claimed to be one of the most severe complications of acromegaly, contributing significantly to mortality in this disease. In fact, an excess of growth hormone (GH) and insulin-like growth factor 1 (IGF-I) causes a specific derangement of cardiomyocytes, leading to abnormalities in cardiac muscle structure and function, inducing a specific cardiomyopathy. In the early phase of acromegaly the excess of GH and IGF-I induces a hyperkinetic syndrome, characterized by increased heart rate and increased systolic output. Concentric hypertrophy is the most common feature of cardiac involvement in acromegaly, found in more than two thirds of patients at diagnosis. This abnormality is commonly associated with diastolic dysfunction and eventually with impaired systolic function ending in heart failure, if the GH/IGF-I excess is left untreated. In addition, abnormalities of cardiac rhythm and of heart valves have also been described in acromegaly. The coexistence of other complications, such as arterial hypertension and diabetes mellitus, aggravates acromegalic cardiomyopathy. Successful control of acromegaly induces a decrease in left ventricular mass and an improvement in diastolic function, while the effects of GH/IGF-I suppression on systolic function are more variable. However, since cardiovascular alterations in young patients with short disease duration are milder than in those with longer disease duration, it is likely to be easier to reverse and/or arrest acromegalic cardiomyopathy in young patients with early-onset disease. In conclusion, careful assessments of cardiac function, morphology, and activity are required in patients with acromegaly. An early diagnosis and prompt effective treatment are important in order to reverse acromegalic cardiomyopathy.

High prevalence of cardiac valve disease in acromegaly: an observational, analytical, case-control study

To characterize mitral and aortic valve abnormalities we performed M-mode, two-dimensional, and pulsed Doppler echocardiography in 42 patients with active acromegaly, 22 patients cured of acromegaly, and 64 controls pair-matched with the patients for sex and age. The overall prevalence of valve abnormalities was higher in both the active patients (86% vs. 24%; P < 0.0001) and the cured patients (73% vs. 9%; P < 0.0001) than in controls. Left ventricular hypertrophy was higher in active (81% vs. 29%; P < 0.0001), but not in cured (41% vs. 14%; P = 0.09) patients than in controls. Cardiac valve abnormalities were associated with left ventricular hypertrophy in both patients and controls, without any difference between them. Conversely, among subjects without left ventricular hypertrophy, mitral and aortic abnormalities were only present in the patients (75% of active and 54% of cured), but not in controls (3% of active controls and 0% of cured controls). In conclusion, patients with active acromegaly and those cured of the disease have a high prevalence of mitral and aortic abnormalities. The persistence of valve disease in patients with cured acromegaly is likely to be correlated with the persistence of left ventricular hypertrophy, which should be carefully and continuously monitored as an aspect of the risk of cardiac dysfunction in these patients.

Primary medical therapy for acromegaly

There is now considerable evidence that the clinical outcome in patients with acromegaly can be improved very substantially by means of better surgical expertise and effective medical therapies used in a flexible and innovative manner. Medical therapy alone in patients who have not undergone surgery or radiotherapy (primary medical therapy) offers the prospect of near normalisation of GH/IGF-I levels together with substantial tumour shrinkage in a significant number of patients.

Reversal of acromegalic cardiomyopathy in young but not in middle-aged patients after 12 months of treatment with the depot long-acting somatostatin analogue octreotide

BACKGROUND

Cardiovascular disease is the most frequent cause of death of patients with acromegaly.

AIM

To investigate whether young patients with a presumed short disease duration are more likely to reverse the acromegalic cardiomyopathy than older patients with longer disease duration.

DESIGN

An open prospective design.

PATIENTS

Ten young (aged < 40 years), and 12 middle-aged (41-59 years) patients with active acromegaly well controlled after 12 months of treatment with the depot formulation of octreotide (OCT-LAR); 22 sex- and age-matched healthy subjects as controls.

METHODS

Left ventricular (LV) mass (LVM) by echocardiography and performance by equilibrium radionuclide angiography were measured before and after 12 months of OCT-LAR treatment.

RESULTS

At study entry, none of the controls and 14 patients (63.4%) of whom six were young (chi2 = 17.7; P < 0.0001) had LV hypertrophy (LVH); none of the controls and four patients of whom one was young had insufficient LV ejection fraction (LVEF) at rest (< 50%); one control and 13 patients (59.1%) of whom five were young (chi2 = 12.7; P < 0.0001) had inadequate LVEF at peak exercise (deltaLVEF; < 5% increase of baseline). After 12 months, no change in haemodynamic and diastolic parameters was observed in both groups, except for a significant decrease in heart rate at peak exercise in young patients (P < 0.0001). The LVM index decreased significantly in both young (124.4 +/- 5.8 vs. 103.4 +/- 3.9 g/m2; P = 0.01) and middle-aged patients (140.9 +/- 7.9 vs. 117.8 +/- 6.6 g/m2; P = 0.03). LVH disappeared in 10 of 14 patients (71.4%): all six young and four of eight middle-aged patients (50%). LVEF at rest and at peak exercise increased significantly in both groups but deltaLVEF increased significantly only in young patients (1.5 +/- 2.9 vs. 13.7 +/- 5.2%, P = 0.04); it normalized in nine of 13 patients (69.2%), four of five young (80%) and four of eight middle-aged patients (50%). Exercise capacity (82.5 +/- 5.3 vs. 110.0 +/- 5.5 W, P = 0.005) and duration (7.3 +/- 0.3 vs. 9.9 +/- 0.4 min, P = 0.0003) also increased only in young patients.

CONCLUSIONS

The acromegalic cardiomyopathy is reversed in most young patients with short disease duration and achieving disease control after OCT-LAR treatment for 12 months, indicating that early diagnosis and effective treatment are essential.

Improvement of left ventricular hypertrophy and arrhythmias after lanreotide-induced GH and IGF-I decrease in acromegaly. A prospective multi-center study

We report the results of a prospective Italian multi-center study of the effects of lanreotide, a slow-release somatostatin analog, on left ventricular morphology and function and on the prevalence of ventricular arrhythmic events in 19 patients with active, newly diagnosed, uncomplicated acromegaly. Cardiac features were evaluated with Doppler-echocardiography and 24-h Holter ECG monitoring at baseline and after 6 months of lanreotide therapy. Fifteen patients (78.9%) had left ventricular hypertrophy. Lanreotide treatment significantly decreased the left ventricular mass (127.8+/-6.9 vs 140.7+/-7.1 g/m2, p<0.001) and left ventricular hypertrophy significantly disappeared in 6 of these patients. Treatment did not significantly affect systolic function, whereas it increased the Doppler-derived early-to-late mitral flow velocity, (E/A) ratio, of early-to-late trans-mitral flow velocity (1.34+/-0.1 vs 1.09+/-0.06, p=0.001). Stroke volume was slightly but not significantly increased after treatment, whereas systolic BP was significantly higher (134+/-14 vs 129+/-13 mmHg, p<0.05). The 24-h mean heart rate was significantly reduced after treatment (66.5+/-11 vs 71.5+/-20 beats/min, p<0.05). Supra-ventricular premature beats (>50/24 h) occurred in 16.6% of patients and were unaffected by treatment. Differently, ventricular premature beats (>50/24 h) occurred in 33.3% of patients before treatment vs 16.5%, after treatment. In conclusion, lanreotide reduced the left ventricular mass, and improved ventricular filling and ventricular arrhythmic profile.

Treatment of an acromegalic cat with the dopamine agonist L-deprenyl

Acromegaly was diagnosed in a 14-year-old domestic short hair cat presented for investigation and management of apparently insulin-resistant diabetes mellitus. Treatment with L-deprenyl and high doses of insulin was commenced. The L-deprenyl did not reduce the requirement for high doses of insulin and did not appear to reduce the clinical signs associated with the disease. The cat was euthanased one year after initial presentation.

High output heart failure in patients with newly diagnosed acromegaly

PURPOSE

We sought to determine the prevalence and characteristics of heart failure in patients with newly diagnosed acromegaly.

SUBJECTS AND METHODS

We assessed 102 consecutive patients who had acromegaly (44 men; age range, 22 to 71 years) for signs and symptoms of heart failure. We included a control group of 33 nonobese healthy subjects (13 men; age range, 26 to 70 years). Cardiac morphologic parameters, left ventricular mass index, ejection fraction, end-systolic wall stress, and cardiac index were measured by echocardiography. Endocrinological assessment was performed in all participants.

RESULTS

Of the 102 patients, 10 (10%) had overt heart failure at the time of diagnosis of acromegaly, 9 of whom were men (P <0.01). Patients with acromegaly and heart failure had an increased mean (+/- SD) left ventricular end-diastolic diameter (76 +/- 11 mm) compared with those without heart failure (53 +/- 6 mm, P <0.001) and control subjects (49 +/- 5 mm, P <0.001). Patients with heart failure had higher left ventricular mass index (230 +/- 56 g/m2 vs. 118 +/- 40 g/m(2), P <0.001) and end-systolic wall stress (237 +/- 79 x 10(3) dyn/cm2 vs. 111 +/- 42 x 10(3) dyn/cm2, P <0.001), but lower ejection fraction (42% +/- 17% vs. 66% +/- 9%, P <0.001), in comparison with patients without heart failure. The mean cardiac index was significantly higher in patients with heart failure (4.3 +/- 1.8 L/min-m2) than in those without heart failure (3.5 +/- 0.8 L/min-m2, P = 0.04) or in control subjects (3.1 +/- 0.6 L/min-m2, P = 0.002). Two factors were independently associated with heart failure in acromegalic patients: cardiac index (odds ratio [OR] per SD of 1.0 L/min-m2 = 16; 95% confidence interval [CI]: 1.8 to 135) and ejection fraction (OR per SD of 12% = 0.7; 95% CI: 0.6 to 0.9).

CONCLUSION

High output heart failure with a modest decline in ejection fraction is frequently detected at the time of diagnosis of acromegaly. Left ventricular hypertrophy in these patients is characterized by a dilated ventricle and an increased left ventricular mass that is primarily due to the enlarged chamber diameter.

Mitral valve repair in a patient with acromegaly: case report

A 61-year-old woman had acromegaly associated with mitral regurgitation (MR) resulting from prolapse of the posterior mitral leaflet. At the age of 51 years, the patient was diagnosed with hypertension and a cardiac murmur. She had the characteristic acromegalic appearance, but without visual disturbance. Blood chemistry revealed an elevated plasma concentration of growth hormone and glucose intolerance. Echocardiography showed remarkable dilation of the left ventricle and prolapse of the anterolateral commissure with severe MR. Magnetic resonance imaging of the brain revealed a pituitary microadenoma. MR was successfully corrected by quadrangular resection of the posterior leaflet, including the prolapsed portion, and prosthetic ring annuloplasty. The patient recovered uneventfully.

Cardiovascular risk factors in acromegaly before and after normalization of serum IGF-I levels with the GH antagonist pegvisomant

Acromegaly is associated with premature cardiovascular mortality. GH replacement therapy decreases inflammatory markers of cardiovascular risk, but little is known about these markers in patients with acromegaly. The GH receptor antagonist, pegvisomant, reduces IGF-I levels in 98% of patients treated. We investigated the effects of GH receptor blockade on inflammatory and other cardiovascular risk markers in active acromegaly. Forty-eight patients with acromegaly and 47 age- and body mass index-matched controls were included. The study consisted of 3 parts: a cross-sectional study, a prospective randomized 12-wk placebo-controlled study, and a longitudinal open-label study of up to 18 months of pegvisomant treatment. After baseline evaluation, patients with acromegaly were randomized to placebo (n = 14), 10 mg (n = 12), 15 mg (n = 10), or 20 mg (n = 12) daily pegvisomant for 12 wk. Subsequently, all patients received at least 10 mg pegvisomant daily for up to 18 months, with dose adjustments to achieve a normal IGF-I level. Anthropometry, GH, IGF-I, and pegvisomant levels were measured monthly. C-reactive protein (CRP), IL-6, homocysteine, lipoprotein(a), glucose, insulin, triglycerides, total cholesterol, and high-density lipoprotein (HDL) and low-density lipoprotein (LDL) cholesterol were determined at baseline, 4 and 12 wk in the placebo-controlled study and at 3-month intervals (during which IGF-I levels were normal) in the longitudinal study. In the cross-sectional study, patients had lower CRP than did controls [median, 0.3 (range, 0.2-0.8) vs. 2.0 (0.6-3.7) mg/liter; P < 0.0001] and had higher insulin [78.6 (55.8-130.2) vs. 54.5 (36.6-77.5) pM, P = 0.0051]. IL-6, homocysteine, triglycerides, lipoprotein(a), LDL cholesterol and HDL cholesterol were not different between groups. In the placebo-controlled study, CRP increased in patients treated with 20 mg pegvisomant, compared with placebo (mean +/- SEM, 13.7 +/- 3.6 vs. 0.5 +/- 3.3 mg/liter; P = 0.010). There were no significant differences in IL-6, homocysteine, glucose, insulin, triglyceride, total cholesterol, LDL cholesterol and HDL cholesterol levels. In the longitudinal open-label study (median duration, 15.6 months), CRP increased by 2.0 +/- 0.5 mg/liter (P = 0.0002). Total cholesterol and triglycerides increased (0.22 +/- 0.11 mM, P = 0.050; and 0.25 +/- 0.09 mM, P = 0.007, respectively), whereas lipoprotein(a) decreased (-70 +/- 33 mg/liter, P = 0.039). Glucose, insulin, homocysteine, HDL cholesterol, and IL-6 did not change. We conclude that patients with active acromegaly have lower CRP and higher insulin levels than healthy controls. Administration of pegvisomant increases CRP levels. We propose that GH secretory status is an important determinant of serum CRP levels, although additional studies are needed to determine the mechanism and significance of this finding.

Improvement of cardiac function after treatment with octreotide followed by trans-sphenoidal surgery in an acromegalic patient who presented with congestive heart failure

Cardiovascular disease is a major cause of mortality and morbidity in patients with acromegaly. We describe the case of a 43-year-old man with acromegaly who presented with severe congestive heart failure. Treatment with the somatostatin analog octreotide improved cardiac function with an increase in left ventricular ejection fraction (LVEF) from 11% to 27%. LVEF further increased to 43% after trans-sphenoidal surgery. Recovery was uneventful. We emphasize the need for early diagnosis and effective treatment of acromegaly to prevent cardiovascular complications. Octreotide therapy or trans-sphenoidal surgery, if possible, should be considered to control cardiac function even in acromegalic patients with severe congestive heart failure.

Inverse association between free insulin-like growth factor-1 and isovolumic relaxation in arterial systemic hypertension

Several trials have suggested that insulin-like growth factor-1 (IGF-1) may have a pathophysiological role in the development of arterial essential hypertension. To verify the possible association of IGF-1 with left ventricular morphological and functional echocardiographic parameters in hypertension, we studied 40 male patients with newly diagnosed hypertension and 15 normotensive control subjects. Doppler echocardiography was performed and circulating free IGF-1 levels were determined in all subjects. Circulating free IGF-1 levels were higher in hypertensives than in control subjects (P<0.01). A significant inverse correlation was observed between free IGF-1 and isovolumic relaxation time in the overall population (r=-0.37, P<0.01) and in hypertensives (r=-0.57, P<0.0001), whereas this relation disappears in normotensives. These results were confirmed by multivariate analysis. The present study confirms that arterial essential hypertension represents a clinical condition associated with an increased synthesis of IGF-1. The observation of an inverse, independent association between free IGF-1 and isovolumic relaxation time suggests 2 alternative hypotheses: a possible beneficial effect of IGF-1 to diastolic relaxation or a resistance to IGF-1 in hypertension.

Pathogenesis and prevalence of hypertension in acromegaly

Hypertension is an important complication of acromegaly, contributing to the increased morbidity and mortality of this condition. Prevalence of hypertension in acromegalic patients is about 35%, ranging from 18 to 60% in different clinical series, and the incidence is higher than in the general population. The lowering of blood pressure observed concomitantly with the reduction in GH levels after successful therapy for acromegaly suggests a relationship between GH and/or IGF-I excess and hypertension. The exact mechanisms underlying the development of hypertension in acromegaly are still not clear but may include several factors depending on the chronic exposure to GH and/or IGF-I excess. Experimental and clinical studies suggest that the anti-natriuretic action of GH (due to direct renal action of GH or IGF-I and/or to indirect, systemic GH or IGF-I-mediated mechanisms) may play a role in the pathogenesis of hypertension. Acromegaly is frequently associated with insulin resistance and hyperinsulinaemia which may induce hypertension by stimulating renal sodium absorption and sympathetic nervous activity. Whether sympathetic tone is altered in acromegalic hypertensive patients remains a matter of debate. Recent studies indicate that an increased sympathetic tone and/or abnormalities in the circadian activity of sympathetic system could play an important role in development and/or maintenance of elevated blood pressure in acromegaly, and may partially account for the increased risk of cardiovascular complications. Acromegalic cardiomiopathy may also concur to elevate blood pressure and can be aggravated by the coexistence of hypertension. Finally, a role of GH and IGF-I as vascular growth factors cannot be excluded. In conclusion, acromegaly is associated with hypertension, but there is still no real consensus in the literature on the mechanisms behind the development of the high blood pressure.

Cardiovascular complications in acromegaly: methods of assessment

Cardiac involvement is common in acromegaly. Evidence for cardiac hypertrophy, dilation and diastolic filling abnormalities has been widely reported in literature. Generally, ventricular hypertrophy is revealed by echocardiography but early data referred increased cardiac size by standard X-ray. Besides, echocardiography investigates cardiac function and value disease. There are new technologic advances in ultrasonic imaging. Pulsed Tissue Doppler is a new non-invasive ultrasound tool which extends Doppler applications beyond the analysis of intra-cardiac flow velocities until the quantitative assessment of the regional myocardial left ventricular wall motion, measuring directly velocities and time intervals of myocardium. The radionuclide techniques permit to study better the cardiac performance. In fact, diastolic as well as systolic function can be assessed at rest and at peak exercise by equilibrium radionuclide angiography. This method has a main advantage of providing direct evaluation of ventricular function, being operator independent. Coronary artery disease has been poorly studied mainly because of the necessity to perform invasive procedures. Only a few cases have been reported with heart failure study by coronarography and having alterations of perfusion which ameliorated after somatostatin analog treatment. More recently, a few data have been presented using perfusional scintigraphy in acromegaly, even if coronary artery disease does not seem very frequent in acromegaly. Doppler analysis of carotid arteries can be also performed to investigate atherosclerosis: however, patients with active acromegaly have endothelial dysfunction more than clear-cut atherosclerotic plaques. In conclusion, careful assessments of cardiac function, morphology and activity need in patients with acromegaly.

Growth hormone and the heart

Impaired cardiovascular function has recently been demonstrated to potentially reduce life expectancy both in GH deficiency and excess. Experimental and clinical studies have supported the evidence that GH and IGF-I are implicated in cardiac development. In most patients with acromegaly a specific cardiomyopathy, characterized by myocardial hypertrophy with interstitial fibrosis, lympho-mononuclear infiltration and areas of monocyte necrosis, results in biventricular concentric hypertrophy. In contrast, patients with childhood or adulthood-onset GH deficiency (GHD) may suffer both from structural cardiac abnormalities, such as narrowing of cardiac walls, and functional impairment, that combine to reduce diastolic filling and impair left ventricular response to peak exercise. In addition, GHD patients may have an increase in vascular intima-media thickness and a higher occurrence of atheromatous plaques, that can further aggravate the haemodynamic conditions and contribute to increased cardiovascular and cerebrovascular risk. However, several lines of evidence have suggested that the cardiovascular abnormalities can be partially reversed by suppressing GH and IGF-I levels in acromegaly or after GH replacement therapy in GHD patients. Recently, much attention has been focussed on the ability of GH to increase cardiac mass suggesting its possible use in the treatment of chronic nonendocrine heart failure. In fact, GH administration can induce an improvement in haemodynamic and clinical status in some patients. Although these data need to be confirmed in more extensive studies, such promising results seem to open new perspectives for GH treatment in humans.

Vascular reactivity in acromegalic patients: preliminary evidence for regional endothelial dysfunction and increased sympathetic vasoconstriction

BACKGROUND AND OBJECTIVES

Hypertension is found in one-third of acromegalic patients. An heterogenous distribution of cardiac output has been recently demonstrated in acromegalic patients with an increased blood flow at the level of the upper limb, suggesting that acromegalic patients may have some degree of endothelial dysfunction. Elsewhere, studies involving hypopituitary GH-deficient adults have shown that GH and/or IGF-I may have direct effect on endothelial function.

SUBJECTS AND METHODS

We thus compared cutaneous vasoreactivity responses in 10 normotensive patients with active acromegaly (A) (six women and four men) aged 25-59 (mean, 43.2 years), whose basal GH and IGF-I levels ranged from 7.4 to 158 mU/l and from 401 to 1690 microg/l, respectively, and in 10 normal age- and sex-matched controls (NC) by means of Laser Doppler flowmetry at the levels of the palm and the dorsum of the right hand. Circulatory skin velocities were studied basally and after increasing skin temperature to 44 degrees C (in order to study direct nonspecific vasodilatation response which is independent of endothelial or autonomous nervous system and reflects normal vascular muscle function), after shear-stress (known to produce flow-dependent vasodilatation, mediated by nitric oxyde (NO) originating from endothelial cells) and after cold-stress applied on the opposite hand (known to produce vaso-constriction mediated by the sympathetic nervous system).

RESULTS

The warm test induced a significant (P<0.001) and similar increase in both dorsal and palmar skin perfusion in A (mean +/- SD) (240+/-96 and 238+/-134%, respectively) and NC (232+/-137 and 233+/-73, respectively). Ischaemia release induced a significant increase in both dorsal and palmar skin blood flows in the two groups (P<0.001), but reactivities in acromegalic patients were about one half of those measured in controls (22.9+/-16.2% (A) vs. 46.9 25% (NC), 2P<0.02, at the level of the dorsum; and 45.0+/-43.6% (A) vs. 104.7+/-40.1 (NC), 2P<0.01, at the level of the palm). Cold pressor test resulted in significant decreases in both cutaneous flows (P<0.01) in the two groups, with a larger vasoconstriction (that did not reach statistical significance) in acromegalic patients as compared with controls (P< 0.10).

CONCLUSION

Vascular smooth cell ability to produce skin vasodilatation is normal but endothelium-dependent vasodilatation appears to be impaired while sympathetic-mediated vasoconstrictive response might be increased in acromegaly. This endothelial dysfunction may contribute to hypertension and represent a risk factor for cardiovascular complications in acromegaly.

[Acromegaly associated with mitral and tricuspid prolapse. Report of a case]

A 65 year-old male with severe systolic mitral and tricuspid valve prolapse, associated with long-standing acromegaly is reported. The non published association could be caused by the effect of growth hormone on the valve connective tissue.

Blood pressure-independent cardiac hypertrophy in acromegalic patients

OBJECTIVE

Acromegaly is frequently associated with an increase in left ventricular mass, even in the absence of systemic hypertension. Pathological studies on acromegalic hearts have shown an extensive interstitial fibrosis, suggesting the existence of a specific acromegalic cardiomyopathy. The aim of this study was to assess left ventricular wall structure in acromegaly by ultrasonic tissue characterization.

DESIGN AND METHODS

We studied 10 untreated acromegalic patients and 10 age-matched healthy control subjects. The echo patterns of two-dimensional long-axis end-diastolic echocardiograms were assessed by colour-scale analysis of the interventricular septum, with estimates of the mean colour scale value, the broad band (Bb) and the derived collagen volume fraction (dCVF). We also measured electrocardiographic QT interval dispersion (QTd) as a marker of dyshomogeneous ventricular repolarization.

RESULTS

Seven patients had left ventricular hypertrophy according to the sex-independent criteria; of these, two had arterial hypertension. None of our patients had echocardiographic evidence of diastolic or systolic dysfunction. All patients showed significantly increased myocardial echoreflectivity (Bb = 106.4+/-12.1 versus 79.3+/-6.5; dCVF% = 2.78+/-0.53 versus 1.58+/-0.29; P < 0.0001) and QTd (66+/-13 ms versus 54+/-8 ms, P < 0.05). A significant correlation was found between dCVF and the duration of acromegaly (r = 0.80; P = 0.005).

CONCLUSIONS

Left ventricular remodelling observed in acromegaly is not related to the presence of arterial hypertension; we hypothesize that the increased echoreflectivity and QTd are long-term consequences of cardiac hypertrophy and prolonged exposure to high levels of growth hormone and insulin-like growth factor-I.

Cardiovascular effects of a single slow release lanreotide injection in patients with acromegaly and left ventricular hypertrophy

In our study we assessed the effects of a single i.m. injection of slow-release Lanreotide (30 mg) (SR-L), a new long-acting somatostain analog, on circulating GH levels, baseline cardiac function (M-mode, 2D guided, doppler-echocardiographic study) and cardiopulmonary response to exercise (cycloergometric test, performed using a computer drived, electrically braked cycle ergometer), tested at baseline, after 7 and 14 days from the injection in 10 acromegalic patients (5 M, 5 F, mean age 57.7 +/- 3.1 yrs, body mass index (BMI) 27 +/- 0.8 kg/m2, blood pressure 141 +/- 6.5/82 +/- 3 mmHg). SR-L administration decreased GH levels in acromegalic patients (mean +/- SEM) from 16.1 +/- 6.9 to 10.8 +/- 5.1 micrograms/L (p = 0.045) after 7 days and to 11.9 +/- 5 micrograms/L (p = 0.078) after 14 days from the injection. Moreover, we observed a significant (p < 0.05) decrease in systolic blood pressure and heart rate at the 7th (135 +/- 6.1 vs 141 +/- 6.5 mmHg, and 68 +/- 2.1 vs 74 +/- 2.1 bpm) and 14th (137 +/- 6.2 vs 141 +/- 6.5 mmHg, and 72 +/- 2 vs 74 +/- 2.1 bpm) day of the study with respect to the baseline values. After SR-L administration we also found an increase in ejection fraction (69 +/- 2 vs 63 +/- 2.3% at 7th day, p = 0.006; 65 +/- 2.3 vs 63 +/- 2.3% at the 14th day, p = 0.027) and shortening fraction (40.8 +/- 1.8 vs 36.6 +/- 1.9% at 7th day, p = 0.005; 38.7 +/- 1.8 vs 36.6 +/- 1.9% at the 14th day, p = 0.045). The positive acute cardiac response to SR-L injection was also demonstrated by the increase in A/E velocity ratios at 7th (1.14 +/- 0.1 vs 0.98 +/- 0.07, p = 0.016) and 14th (1.04 +/- 0.08 vs 0.98 +/- 0.07, p = 0.008) day of the study. After SR-L injection, exercise capacity and VO2 at anaerobic threshold were also increased with respect to the baseline test: 61.1 +/- 8.2 vs 38.9 +/- 6.8 watts (p = 0.002) and 1012.4 +/- 71.5 vs 915.3 +/- 77.8 mL/min (p = 0.033) after 7 days, and 61.4 +/- 7.2 vs 38.9 +/- 6.8 watts (p = 0.002) and 1010.1 +/- 62.5 vs 915.3 +/- 77.8 mL/min (p = 0.010) after 14 days from the injection. In conclusion, these results suggest that in acromegalic patients: (1) SR-L causes a rapid improvement in baseline cardiac function and in cardiopulmonary performance during exercise in acromegaly; (2) the endocrine (decrease in GH levels) and echocardiographic responses to SR-L are maximal after 7 days from the injection, whereas the effect of SR-L on the exercise performance are longer lasting.

Insulin-like growth factor I: an attractive option for chronic heart failure?

Chronic congestive heart failure is a syndrome with a poor prognosis. Currently, the only therapy providing the possibility of long term survival is heart transplantation. Therefore, new therapeutic strategies continue to be investigated. One such new approach may be the application of recombinant human insulin-like growth factor (IGF)-1. IGF-1 has both acute and long term cardiovascular effects. Acute administration of IGF-1 resulted in a reduction in afterload and positive inotropic effects in patients with heart failure. In vitro and animal studies have demonstrated that IGF-1 can stimulate myofibril formation. In addition, IGF-1 administration has beneficial metabolic effects. The benefits of prolonged IGF-1 therapy have yet to be investigated.

Epidemiology of acromegaly

Acromegaly is a consequence of chronic growth hormone (GH) excess, due in the majority of cases to a GH-secreting pituitary adenoma, and occurring with a population prevalence of 60 per million and an incidence of 3-4 per million per year. Males and females appear to be equally affected with an average age of presentation of 44 years. Younger patients may have more aggressive tumours and higher GH concentrations. There is co-existent hyperprolactinaemia in about one third of cases, and a variable proportion of [figure: see text] tumours appear to have activating mutations of the gsp gene or other genetic abnormalities. Acute complications such as carpal tunnel syndrome, sweating and obstructive sleep apnoea are usually readily reversible with treatment of the condition, but chronic complications such as hypertension, diabetes and heart disease are less readily corrected and post-treatment GH levels of < 2.5 ug/L (5 mU/L) are needed to achieve the prevalence found in the general community. Such 'curative' levels of GH are achieved in only about 50% of patients with current therapies, and as a result there is an ongoing excess of patients with chronic complications of acromegaly leading to increased morbidity and mortality from the disorder, with observed-to-expected mortality ratios ranging from 1.6-3.3 and only approaching unity in those with growth hormone levels < 2.5 ug/L following treatment. Prognostic factors include in some studies the presence of diabetes and [table: see text] hypertension prior to diagnosis as well as measures of exposure to excessive growth hormone derived from the product of preoperative serum GH and the time from first symptoms to treatment. Overall, however, the most important prognostic variable appears to be the serum GH concentration achieved by treatment, with an increasing consensus that this needs to be < 2.5 ug/L (5 mU/L) to achieve cure of the condition.

Regression of acromegalic left ventricular hypertrophy after lanreotide (a slow-release somatostatin analog)

A group of 13 acromegalic patients was treated with lanreotide for 18 months and followed-up echocardiographically; these patients showed significant correlations between the decrease of both growth hormone (GH) and insulin-like growth factor-1 and the decrease of left ventricular mass index. This documents a regression of left ventricular hypertrophy in acromegaly after lanreotide treatment, the degree of which is dependent on the magnitude of the decrease of GH and insulin-like growth factor-1 serum levels.

Cell death in acromegalic cardiomyopathy

BACKGROUND

Prolonged untreated acromegaly leads to a nonspecific myopathy characterized by ventricular dysfunction and failure. However, the mechanisms responsible for the alterations of cardiac pump function remain to be defined. Because cell death is implicated in most cardiac disease processes, the possibility has been raised that myocyte apoptosis may occur in the acromegalic heart, contributing to the deterioration of ventricular hemodynamics.

METHODS AND RESULTS

Ten acromegalic patients with diastolic dysfunction and 4 also with systolic dysfunction were subjected to electrocardiography, Holter monitoring, 2-dimensional echocardiography, cardiac catheterization, and biventricular and coronary angiography before surgical removal of a growth hormone-secreting pituitary adenoma. Endomyocardial biopsies were obtained and analyzed quantitatively in terms of tissue scarring and myocyte and nonmyocyte apoptosis. Myocardial samples from papillary muscles of patients who underwent valve replacement for mitral stenosis were used for comparison. The presence of apoptosis in myocytes and interstitial cells was determined by confocal microscopy with the use of 2 histochemical methods, consisting of terminal deoxynucleotidyl transferase (TdT) assay and Taq probe in situ ligation. Acromegaly was characterized by a 495-fold and 305-fold increase in apoptosis of myocytes and nonmyocytes, respectively. The magnitude of myocyte apoptosis correlated with the extent of impairment in ejection fraction and the duration of the disease. A similar correlation was found with the magnitude of collagen accumulation, indicative of previous myocyte necrosis. Myocyte death was independent from the hormonal levels of growth hormone and insulin-like growth factor-1. Apoptosis of interstitial cells did not correlate with ejection fraction.

CONCLUSIONS

Myocyte cell death, apoptotic and necrotic in nature, may be critical for the development of ventricular dysfunction and its progression to cardiac failure with acromegaly.

Decreased regional blood flow in patients with acromegaly

BACKGROUND AND AIMS

One-third of acromegalic patients have hypertension. Acromegaly is also associated with intrinsic cardiac abnormalities known collectively as a hyperkinetic heart syndrome, which is characterized by an increased cardiac index and decreased systemic vascular resistance. As a result, blood flow should be increased in the regional vascular beds of acromegalic patients. The aim of the study was to measure, using direct methods, blood flow and vascular resistance at the level of the brachial artery in acromegalic patients with a confirmed hyperkinetic heart syndrome.

PATIENTS AND CONTROLS

Twelve patients with active acromegaly (five females, seven males; mean (+/- SD) age, 43 +/- 10 years) were studied. Twelve age- and sex-matched normal subjects served as controls.

METHODS

Right heart catheterization was used to measure the cardiac index and stroke volume and to calculate systemic vascular resistance in the acromegalic patients. Brachial haemodynamics were evaluated with a two-dimensional pulsed Doppler system (double transducer probe and range-gated time system of reception). The mean diameter of the brachial artery and mean blood velocity were measured and used to calculate mean blood flow. Vascular resistance was calculated in the brachial artery as the mean arterial pressure/blood flow ratio.

RESULTS

Age, body weight, height, body surface area and heart rate were similar in the acromegalic patients and controls, while mean arterial pressure was higher in patients. The cardiac index and stroke volume were increased in the acromegalic patients, at 4.08 +/- 0.47 (mean +/- SD) l/min/m2 body surface area and 116.7 +/- 19.4 ml, respectively, while systemic vascular resistance was low (12.5 +/- 2.1 U). Brachial artery diameter was similar in the patients and controls. Brachial artery mean blood velocity (P < 0.01) and mean blood flow (P < 0.05) were lower in the patients than in the controls (3.35 +/- 1.26 vs. 5.12 +/- 1.74 cm/s, and 16.4 +/- 9.4 vs. 25.6 +/- 11.6 ml/min/m2, respectively). The higher mean arterial pressure and lower mean blood flow resulted in higher forearm vascular resistance in the patients than in the controls (132 +/- 61 vs. 83.8 +/- 47 mmHg/ml/s/m2, respectively, P < 0.01).

CONCLUSION

While cardiac output is increased and systemic vascular resistance is decreased in active acromegaly, direct measurement of brachial artery haemodynamics showed lower regional blood flow and increased local resistance relative to healthy controls. These results suggest a heterogeneous distribution of cardiac output in acromegaly.

Acromegalic cardiomyopathy: evaluation of the left ventricular diastolic function in the subclinical stage

It is recently shown that the majority of acromegalic patients without concomitant heart disease have diastolic dysfunction at rest. The aim of this study is to evaluate left ventricular diastolic function in normotensive acromegalic patients without any evidence of heart disease. Eleven acromegalic patients and 16 normal subjects of comparable age and sex distribution were studied by echocardiography. Left ventricular end-diastolic diameter, interventricular septal thickness, left ventricular posterior wall thickness, left ventricular end-diastolic volume and stroke volume were found to be significantly higher in acromegalic patients. Left ventricular mass and left ventricular mass index increased significantly in acromegalics in comparison with controls (229.16 +/- 46.11 g versus 167.17 +/- 24.57 g and 124.99 +/- 26.91 g/m2 versus 95.09 +/- 13.29 g/m2 respectively, p < 0.001). Mitral A wave desceleration rate and isovolumetric relaxation time (IVRT)-two of the studied parameters of left ventricular diastolic filling- were significantly prolonged in patients as compared with controls (p = 0.03 and p < 0.001 respectively). Four (36%) of the acromegalic patients had peak early/late diastolic mitral velocity ratio lower than 1, indicating diastolic dysfunction. All of the patients had IVRT longer than 90 ms (mean + 2 standart deviations of normals). It is concluded that in acromegalic patients without any other evidence of heart disease left ventricular diastolic function is impaired. This indicates a specific cardiomyopathy exists in the subclinical stage. IVRT is found to be more sensitive than other studied parameters for detecting diastolic dysfunction at this stage.

LDL subfractions in acromegaly: relation to growth hormone and insulin-like growth factor-I

Acromegaly is associated with changes in lipoprotein metabolism and an excess in cardiovascular mortality. We have examined low density lipoprotein (LDL) subfraction distribution in 24 patients with active acromegaly and in controls matched for age, sex and body mass index. LDL was subfractionated by density gradient ultracentrifugation. The concentration of small dense LDL-III was significantly higher in the acromegalic patients compared to the controls (94.2 +/- 44.9 versus 67.2 +/- 30.4 mg/dl, P < 0.05) and there was a concomitant reduction in the intermediate subfraction LDL-II (124.8 +/- 31.3 versus 149.9 +/- 30.0 mg/dl, P < 0.05). Univariate analysis showed that both growth hormone (GH) and insulin-like growth factor (IGF)-I correlated with LDL-III and inversely with LDL-II. Acromegalic patients were found to have lower hepatic lipase (HL) and lipoprotein lipase (LPL) activities than controls (HL: 13.29 +/- 6.56 versus 21.58 +/- 7.27 micromol FFA released/ml/h, P < 0.001: LPL: 7.22 +/- 3.04 versus 11.53 +/- 7.85 micromol FFA released/ml/h, P < 0.05) whereas plasma cholesteryl ester transfer protein (CETP) activity was significantly increased (8.15 +/- 1.81 versus 5.54 +/- 1.86 pmol/microl/h, P < 0.001). Both GH and IGF-I were significantly associated with HL, LPL and CETP activities. Multivariate analysis on this relatively small sample size showed that in normal subjects, triglyceride and HL activity were the major determinants of LDL-III. In contrast, GH and HDL were the main determinants in acromegaly, accounting for 32 and 24% in the variability of LDL-III respectively. In conclusion, GH excess has a direct effect on LDL subfraction distribution.

Recombinant growth hormone: a new cardiovascular drug therapy

GH has an important role in normal cardiovascular physiologic functioning, working indirectly through effects on IGF-1. An excess or deficiency of GH causes an increased rate of cardiovascular disease, including cardiomyopathy. A relative GH deficiency in older subjects may also increase cardiovascular morbidity and mortality risk. In replacement doses, GH can enhance myocardial contractility; can decrease peripheral vascular resistance; and can reduce total cholesterol and LDL-cholesterol values and fibrinogen and PAI levels. These effects of GH, coupled with the ability to improve skeletal muscle function and reduce adiposity, make it an attractive treatment for patients with CHF and a potential maintenance drug for elderly people. Clinical trials, including studies with GHRH that may reduce the adverse effects of GH therapy, such as hyperglycemia and hypertension, are now in progress.

Doppler echocardiographic patterns in patients with acromegaly

Cardiovascular problems have long been recognized as responsible for an increased morbidity and mortality in patients with acromegaly. The aim of the present study was to evaluate echocardiographically the prevalence of cardiomyopathy in a cohort of acromegalic patients and to analyze the results in relation to demographic, clinical and hormonal data. This study, a retrospective controlled clinical trial, was performed in 25 acromegalic patients, 12 men and 13 women aged 26-66 years (mean: 52.6). Fifteen patients had an active disease, 10 were cured by previous pituitary surgery. The same echocardiographic parameters were analyzed in 50 healthy subjects aged 30-70 years (mean: 51.4). Serum GH was determined on at least 4 samples drawn over 24 hours and plasma IGF-I on a single point. Standardized parameters of diastolic and systolic function were evaluated by real-time Doppler echocardiography. Twelve patients with active acromegaly underwent also 48-hour ECG registering. Left ventricular (LV) hypertrophy was found in 14/25 patients (56%). No difference was found between patients with active disease (53%) and patients with cured acromegaly (60%). LV mass index was significantly increased in acromegalics in comparison with healthy subjects (137 +/- 43 g/m2 vs 96 +/- 16 g/m2, p < 0.01) and also the indices of LV diastolic function were significantly impaired. Asymmetric septal hypertrophy was found only in one patient. Hypertension was detected in 9/25 patients (36%) without difference between patients with active or cured disease (40% vs 30%, NS). No significant correlation was found between hormonal or clinical data and echocardiographic findings. During Holter monitoring, heart rate of acromegalics was not significantly different from that of controls (78 +/- 12 bpm vs 72 +/- 10 bpm, NS) and only isolated supraventricular or ventricular premature complexes (Lown class 1) were detected. In conclusion, this study provides evidence of subclinical LV dysfunction in acromegaly in the absence of other known causes of heart disease and no significant difference in echocardiographic pattern was apparent between active or cured acromegalics.