Cardiovascular effects of the somatostatin analog octreotide in acromegaly

Acromegalic Cardiomyopathy: An Entity on its own? The Effects of GH and IGF-I Excess and Treatment on Cardiovascular Risk Factors

Acromegaly is a chronic disease resulting from constantly elevated concentrations of growth hormone (GH) and insulin-like growth factor I (IGF-I). If not adequately treated, GH and IGF-I excess is associated with various cardiovascular risk factors. These symptoms mainly include hypertension and impaired glucose metabolism, which can be observed in approximately one-third of patients. Other comorbidities are dyslipidemia and the presence of obstructive sleep apnea syndrome. However, even in the absence of conventional cardiovascular risk factors, myocardial hypertrophy can occur, which reflects the impact of GH and IGF-I excess itself on the myocardium and is defined as acromegalic cardiomyopathy. Whereas previous echocardiography-based studies reported a high prevalence of cardiomyopathy, this prevalence is much lower in cardiac magnetic resonance imaging-based studies. Myocardial hypertrophy in acromegaly is due to a homogeneous increase in the intracellular myocardial mass and extracellular myocardial matrix and improves following successful treatment through intracellular changes. Intramyocardial water retention or ectopic lipid accumulation might not be of relevant concern. Successful treatment significantly improves myocardial morphology, as well as cardiovascular risk factors. In addition to GH/IGF-I-lowering therapy, the diagnosis and treatment of cardiovascular complications is crucial for the successful management of acromegaly.

Chemical phenotypes of intrinsic cardiac neurons in the newborn pig (Sus scrofa domesticus Erxleben, 1777)

Intrinsic cardiac neurons (ICNs) are crucial cells in the neural regulation of heart rhythm, myocardial contractility, and coronary blood flow. ICNs exhibit diversity in their morphology and neurotransmitters that probably are age-dependent. Therefore, neuroanatomical heart studies have been currently focused on the identification of chemical phenotypes of ICNs to disclose their possible functions in heart neural regulation. Employing whole-mount immunohistochemistry, we examined ICNs from atria of the newborn pigs (Sus scrofa domesticus) as ICNs at this stage of development have never been neurochemically characterized so far. We found that the majority of the examined ICNs (>60%) were of cholinergic phenotype. Biphenotypic neuronal somata (NS), that is, simultaneously positive for two neuronal markers, were also rather common and distributed evenly within the sampled ganglia. Simultaneous positivity for cholinergic and adrenergic neuromarkers was specific in 16.4%, for cholinergic and nitrergic-in 3.5% of the examined NS. Purely either adrenergic or nitrergic ICNs were observed at 13% and 3.1%, correspondingly. Purely adrenergic and nitrergic NS were the most frequent in the ventral left atrial subplexus. Similarly to neuronal phenotype, sizes of NS also varied depending on the atrial region providing insights into their functional implications. Axons, but not NS, positive for classic sensory neuronal markers (vesicular glutamate transporter 2 and calcitonin gene-related peptide) were identified within epicardiac nerves and ganglia. Moreover, a substantial number of ICNs could not be attributed to any phenotype as they were not immunoreactive for antisera used in this study. Numerous dendrites with putative peptidergic and adrenergic contacts on cholinergic NS contributed to neuropil of ganglia. Our observations demonstrate that intrinsic cardiac ganglionated plexus is not fully developed in the newborn pig despite of dense network of neuronal processes and numerous signs of neural contacts within ganglia.

Cardiovascular complications of acromegaly

Acromegaly is a chronic disease due to growth hormone (GH) and insulin-like growth factor 1 (IGF-1) excess. It is associated with various systemic complications including cardiovascular disease. Arterial hypertension occurs in about 20% to 30% of patients. Its pathogenesis is mainly related to the increase in plasma volume secondary to a sodium retaining actions of GH and IGF-1 in the kidney, but abnormalities in vessel architecture and reactivity participate. Left ventricular hypertrophy and diastolic dysfunctions were frequently reported in echo-based studies and are mostly mild and without clinical consequences. Recent cardiac MRI studies described a much lower frequency of myocardial hypertrophy than echo-based assessments. Progression to systolic dysfunction with congestive heart failure is nowadays very rare. Risk of coronary heart disease and of clinically significant arrythmias does not seem to be increased. Acromegaly-related cardiac valve abnormalities may be related to fibrotic changes and seem to persist after effective treatment of acromegaly. Advances in acromegaly treatment over the last decades significantly diminished the cardiovascular burden of the disease, with the cardiovascular disease anymore being the leading cause of death.

Effects of somatostatin analog treatment on cardiovascular parameters in patients with acromegaly: A systematic review

Background:

There is a belief that in patients with acromegaly, first-generation somatostatin analogs (SSAs) might improve cardiovascular (CV) structure and function. However, most published clinical trials involved only a few patients and their results are rather variable. We aimed to conduct a systematic review on available studies on the impact of these drugs on CV parameters.

Materials and Methods:

A literature search was conducted in MEDLINE (OVID), EMBase, Cochrane, and ISI Web of Science for citations published until April 30 2018 to identify studies on our objective that considered changes in CV parameters. For this search, we established a Boolean search strategy using keywords related to “acromegaly,” “Somatostatin analog,” and “cardiovascular diseases and parameters.” All study types except for case reports or conference abstracts were included. Twenty-four studies (n = 558) fulfilled the inclusion criteria and were selected for final analysis.

Results:

In 12 studies (n = 350), decrease in heart rate (HR) and in 4 studies (n = 128), decrease in blood pressure (BP) was significant. In 15 studies (n = 320), left ventricular mass index (LVMi) changes were significant. In 9 studies (n = 202), the early diastole to peak velocity flow in late diastole (E/A ratio) was evaluated, and in 5 of them (n = 141), the improvement was significant. Eighteen studies (n = 366) examined changes in left ventricular ejection fraction (LVEF), 5 of which (n = 171) reported that these changes were significant. Decrease of left ventricular end-diastolic diameter was reported in only 2 studies (n = 27).

Conclusion:

We found that first-generation SSAs have a beneficial effect on cardiac parameters such as HR and LVMi. For other parameters such as LVEF, BP, LV diameter, and E/A ratio, we were not able to draw a firm conclusion.

Complete Heart Block due to Octreotide Infusion in Patient with Cryptogenic Cirrhosis

A 62-year-old man was admitted to the emergency department (ED) with the complaint of intense hematemesis. He was admitted to intensive care unit because of acute esophageal variceal hemorrhage. He underwent sclerotherapy followed by a slow infusion of intravenous octreotide. Complete heart block occured in the patient during octreotide infusion and infusion was stopped. Temporary pacemaker was placed in the patient's heart. Normal sinus rhythm was observed in the follow up one day later and the pacemaker was removed from patient. He was discharged upon recommendation.

A Novel Somatostatin-Dopamine Chimera (BIM23B065) Reduced GH Secretion in a First-in-Human Clinical Trial

CONTEXT

A somatostatin-dopamine chimera (BIM23B065) was under investigation to reduce GH secretion for the treatment of pituitary adenomas.

OBJECTIVE

To determine pharmacokinetics, safety, and tolerability and to monitor hormonal changes after single and multiple subcutaneous BIM23B065 administrations.

DESIGN

Randomized, double-blind, placebo-controlled, parallel-group design with five single and three 13-day multiple ascending-dose cohorts.

PATIENTS

A total of 63 healthy male white volunteers were enrolled (47 active, 16 placebo).

MAIN OUTCOME MEASURES

Pharmacokinetics, GH, prolactin (PRL), IGF-1, GH after GHRH administration, and general clinical safety criteria.

RESULTS

The maximum dosage of BIM23B065 administered in this study was 1.5 mg. BIM23B065 reduced the mean GH concentrations after 8 and 13 days of treatment. A decrease in GH release after GHRH administration indicated inhibition of the hypothalamic-pituitary-somatotropic axis. IGF-1 was not altered after single doses but showed a significant change from baseline after multiple dosing. PRL secretion was reduced in all subjects who were treated. Orthostatic hypotension and injection site reactions were commonly observed at high dosages. A 6-day uptitration period was included to successfully lower the cardiovascular effects in the multiple ascending dose part of the study.

CONCLUSIONS

Proof of pharmacology of BIM23B065 was shown by a reduction in GH, IGF-1, and PRL concentrations in healthy male volunteers, supporting activity of the somatostatin analog and dopamine agonist moieties. The safety and tolerability of the higher dosing regions was limited mainly by orthostatic hypotension.

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.

Cardiovascular Disease and Sleep-Disordered Breathing in Acromegaly

Treatment goals in acromegaly include symptom relief, tumour control and reversal of the excess morbidity and mortality associated with the disorder. Cardiovascular complications include concentric biventricular hypertrophy and cardiomyopathy, hypertension, valvular heart disease and arrhythmias, while metabolic disturbance (insulin resistance/diabetes mellitus, dyslipidaemia) further increases the risk of cardiovascular and cerebrovascular events. Sleep-disordered breathing (in the form of sleep apnoea) is also common in patients with acromegaly and may exacerbate cardiovascular dysfunction, in addition to contributing to impaired quality of life. Accordingly, and in keeping with evidence that cardiorespiratory complications in acromegaly are not automatically reversed/ameliorated simply through the attainment of 'safe' growth hormone and insulin-like growth factor 1 levels, recent guidelines have emphasised the need not only to achieve stringent biochemical control, but also to identify and independently treat these comorbidities. It is important, therefore, that patients with acromegaly are systematically screened at diagnosis, and periodically thereafter, for the common cardiovascular and respiratory manifestations and that biochemical targets do not become the only treatment goal.

Growth hormone, insulin-like growth factor-1, and the kidney: pathophysiological and clinical implications

Besides their growth-promoting properties, GH and IGF-1 regulate a broad spectrum of biological functions in several organs, including the kidney. This review focuses on the renal actions of GH and IGF-1, taking into account major advances in renal physiology and hormone biology made over the last 20 years, allowing us to move our understanding of GH/IGF-1 regulation of renal functions from a cellular to a molecular level. The main purpose of this review was to analyze how GH and IGF-1 regulate renal development, glomerular functions, and tubular handling of sodium, calcium, phosphate, and glucose. Whenever possible, the relative contributions, the nephronic topology, and the underlying molecular mechanisms of GH and IGF-1 actions were addressed. Beyond the physiological aspects of GH/IGF-1 action on the kidney, the review describes the impact of GH excess and deficiency on renal architecture and functions. It reports in particular new insights into the pathophysiological mechanism of body fluid retention and of changes in phospho-calcium metabolism in acromegaly as well as of the reciprocal changes in sodium, calcium, and phosphate homeostasis observed in GH deficiency. The second aim of this review was to analyze how the GH/IGF-1 axis contributes to major renal diseases such as diabetic nephropathy, renal failure, renal carcinoma, and polycystic renal disease. It summarizes the consequences of chronic renal failure and glucocorticoid therapy after renal transplantation on GH secretion and action and questions the interest of GH therapy in these conditions.

A comprehensive study of clinical, biochemical, radiological, vascular, cardiac, and sleep parameters in an unselected cohort of patients with acromegaly undergoing presurgical somatostatin receptor ligand therapy

CONTEXT

Attainment of safe GH and IGF-1 levels is a central goal of acromegaly management.

OBJECTIVE

The aim of this study was to determine the extent to which reductions in GH and IGF-1 concentrations correlate with amelioration of radiological, metabolic, vascular, cardiac, and respiratory sequelae in a single unselected patient cohort.

STUDY DESIGN

This was a prospective, within-subject comparison in 30 patients with newly diagnosed acromegaly (15 women and 15 men: mean age, 54.3 years; range, 23-78 years) before and after 24 weeks of lanreotide Autogel (ATG) therapy.

RESULTS

Reductions in GH and IGF-1 concentrations and tumor volume were observed in all but 2 patients (median changes [Δ]: GH, -6.88 μg/L [interquartile range -16.78 to -3.32, P = .000001]; IGF-1, -1.95 × upper limit of normal [-3.06 to -1.12, P = .000002]; and pituitary tumor volume, -256 mm(3) [-558 to -72.5, P = .0002]). However, apnea/hypopnea index scores showed highly variable responses (P = .11), which were independent of ΔGH or ΔIGF-1, but moderately correlated with Δweight (R(2) = 0.42, P = .0001). Although systolic (P = .33) and diastolic (P = .76) blood pressure were unchanged, improvements in arterial stiffness (aortic pulse wave velocity, -0.4 m/s [-1.2 to +0.2, P = .046]) and endothelial function (flow mediated dilatation, +1.73% [-0.32 to +6.19, P = .0013]) were observed. Left ventricular mass index regressed in men (-11.8 g/cm(2) [-26.6 to -1.75], P = .019) but not in women (P = .98). Vascular and cardiac changes were independent of ΔGH or ΔIGF-1 and also showed considerable interindividual variation. Metabolic parameters were largely unchanged.

CONCLUSIONS

Presurgical ATG therapy lowers GH and IGF-1 concentrations, induces tumor shrinkage, and ameliorates/reverses cardiac, vascular, and sleep complications in many patients with acromegaly. However, responses vary considerably between individuals, and attainment of biochemical control cannot be assumed to equate to universal complication control.

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.

Pathophysiology of renal calcium handling in acromegaly: what lies behind hypercalciuria?

BACKGROUND

Hypercalciuria is frequent in patients with acromegaly, but it is unclear how GH/IGF-I regulate renal calcium handling. Elevated fasting plasma calcium levels despite increased glomerular filtration suggest enhanced renal calcium reabsorption.

OBJECTIVE

The aim of this study was to investigate the impact of acromegaly on phosphocalcium metabolism.

DESIGN AND SETTING

We conducted a prospective sequential study at a tertiary referral medical center and clinical investigation center (www.ClinicalTrials.gov Identifier: NCT00531908).

INTERVENTION

Sixteen consecutive patients (five females/11 males) with acromegaly received a single iv infusion of 25 mg of furosemide to induce an acute increase in calcium and magnesium delivery to distal tubular segments during a high-sodium diet with stable dietary calcium, magnesium, and phosphate intake.

MEASUREMENTS

Baseline plasma and urine electrolytes, plasma calciotropic hormones, and furosemide-induced changes in the fractional excretion and tubular reabsorption of Na, Ca, and Mg were measured before and 6 months (range, 1-12) after effective treatment of acromegaly.

RESULTS

Serum IGF-I concentrations normalized in all the patients after acromegaly treatment. Compared with controlled acromegaly, active acromegaly was associated with higher fasting plasma (P = 0.0002) and urinary calcium (P = 0.0003) levels, lower PTH levels (P = 0.0075), higher calcitriol levels (P = 0.0137), higher phosphatemia (P<0.0001) and tubular phosphate reabsorption (P = 0.0002), and a lower calciuric (P = 0.0327) but not magnesiuric response to furosemide related to higher baseline and postfurosemide tubular calcium (P = 0.0034 and P = 0.0081, respectively), but not magnesium reabsorption.

CONCLUSION

The IGF-I-mediated and PTH-independent increase in calcitriol synthesis in acromegaly is responsible for both absorptive hypercalciuria and increased fasting plasma calcium linked to enhanced distal tubular calcium reabsorption, as shown by the selectively diminished calciuric response to furosemide.

The GH/IGF-1 Axis and Heart Failure

The growth hormone (GH)/insulin-like growth factor 1 (IGF-1) axis regulates cardiac growth, stimulates myocardial contractility and influences the vascular system. The GH/IGF-1 axis controls intrinsic cardiac contractility by enhancing the intracellular calcium availability and regulating expression of contractile proteins; stimulates cardiac growth, by increasing protein synthesis; modifies systemic vascular resistance, by activating the nitric oxide system and regulating non-endothelial-dependent actions. The relationship between the GH/IGF-1 axis and the cardiovascular system has been extensively demonstrated in numerous experimental studies and confirmed by the cardiac derangements secondary to both GH excess and deficiency. Several years ago, a clinical non-blinded study showed, in seven patients with idiopathic dilated cardiomyopathy and chronic heart failure (CHF), a significant improvement in cardiac function and structure after three months of treatment with recombinant GH plus standard therapy for heart failure. More recent studies, including a small double-blind placebo-controlled study on GH effects on exercise tolerance and cardiopulmonary performance, have shown that GH benefits patients with CHF secondary to both ischemic and idiopathic dilated cardiomyopathy. However, conflicting results emerge from other placebo-controlled trials. These discordant findings may be explained by the degree of CHF-associated GH resistance. In conclusion, we believe that more clinical and experimental studies are necessary to exactly understand the mechanisms that determine the variable sensitivity to GH and its positive effects in the failing heart.

Body fluid expansion in acromegaly is related to enhanced epithelial sodium channel (ENaC) activity

BACKGROUND

Soft-tissue swelling and increased extracellular volume, two features of acromegaly, are related to the antinatriuretic effects of excess GH/IGF-I, but the precise pathophysiological mechanism is unclear.

OBJECTIVE

Our objective was to determine the effect of the GH excess on renal and extrarenal epithelial sodium channel (ENaC) activity.

DESIGN AND SETTING

We conducted a prospective randomized open-label blinded-endpoint (PROBE) crossover study (www.ClinicalTrials.gov Identifier: NCT00531908) at a tertiary referral medical center and clinical investigation center.

INTERVENTION

Sixteen patients (five females, 11 males) with acromegaly were randomly assigned to receive 20 mg amiloride (an ENaC blocker) and 25 mg furosemide (a Na-K-2Cl cotransporter blocker) under a high-sodium diet to suppress endogenous renin and aldosterone.

MEASUREMENTS

Diuretic-induced changes in the urinary Na/K ratio (reflecting coupling between ENaC-mediated Na reabsorption and distal K secretion) and the intranasal amiloride-sensitive potential (reflecting extrarenal ENaC activity) were measured before and 6 months after (range, 1-12 months) treatment of acromegaly.

RESULTS

Serum IGF-I concentrations normalized in all the patients after treatment of acromegaly. Baseline plasma renin and aldosterone concentrations remained unchanged after treatment. Active acromegaly, compared with controlled disease, was associated with an enhanced response [median (interquartile range)] to amiloride [urinary Na/K, 13.9 (9.8-19.5) vs. 6.3 (4.3-8.4) mmol/mmol, P = 0.0003], a reduced response to furosemide [urinary Na/K, 5.2 (4.6-7.2) vs. 7.1 (5.4-8.8) mmol/mmol, P =0.0151], and an increased intranasal amiloride-sensitive potential [5.8 (11.9-3.8) vs. 4.2 (6.4-2.1) mV, P = 0.031], respectively.

CONCLUSION

GH/IGF-I excess in humans is associated with enhanced renal and extrarenal ENaC activity that may contribute to soft-tissue swelling and volume expansion in acromegaly.

Acromegaly pathogenesis and treatment

Dysregulated growth hormone (GH) hypersecretion is usually caused by a GH-secreting pituitary adenoma and leads to acromegaly - a disorder of disproportionate skeletal, tissue, and organ growth. High GH and IGF1 levels lead to comorbidities including arthritis, facial changes, prognathism, and glucose intolerance. If the condition is untreated, enhanced mortality due to cardiovascular, cerebrovascular, and pulmonary dysfunction is associated with a 30% decrease in life span. This Review discusses acromegaly pathogenesis and management options. The latter include surgery, radiation, and use of novel medications. Somatostatin receptor (SSTR) ligands inhibit GH release, control tumor growth, and attenuate peripheral GH action, while GH receptor antagonists block GH action and effectively lower IGF1 levels. Novel peptides, including SSTR ligands, exhibiting polyreceptor subtype affinities and chimeric dopaminergic-somatostatinergic properties are currently in clinical trials. Effective control of GH and IGF1 hypersecretion and ablation or stabilization of the pituitary tumor mass lead to improved comorbidities and lowering of mortality rates for this hormonal disorder.

Pituitary tumours: acromegaly

Excessive production of the growth hormone (GH) is responsible for acromegaly. It is related to a pituitary GH-secreting adenoma in most cases. Prevalence is estimated 40-130 per million inhabitants. It is characterised by slowly progressive acquired somatic disfigurement (mainly involving the face and extremities) and systemic manifestations. The rheumatologic, cardiovascular, respiratory and metabolic consequences determine its prognosis. The diagnosis is confirmed by an increased serum GH concentration, unsuppressible by an oral glucose load and by detection of increased levels of insulin-like growth factor-I (IGF-I). Treatment is aimed at correcting (or preventing) tumour compression by excising the disease-causing lesion, and at reducing GH and IGF-I levels to normal values. When surgery, the usual first-line treatment, fails to correct GH/IGF-I hypersecretion, medical treatment with somatostatin analogues and/or radiotherapy can be used. The GH-receptor antagonist (pegvisomant) is helpful in patients who are resistant to somatostatin analogues. Thanks to this multistep therapeutic strategy, adequate hormonal disease control is achieved in most cases, allowing a normal life expectancy.

Octreotide-LAR vs lanreotide-SR as first-line therapy for acromegaly: a retrospective, comparative, head-to-head study

No head-to-head comparisons are available to analyze the efficacy of octreotide (LAR) and lanreotide (LAN) as first-line treatment of acromegaly.We compared the efficacy of these two drugs in 54 newly diagnosed patients (21 women, 33 men), 27 treated with LAR (10-30 mg every 28 days) and 27 with LAN (60-90 mg/28 days), for 12 months. Each LAR-treated patient was matched with one LAN-treated patient as for GH levels, sex, and age (+/-5 yr). Outcome measures were GH and IGF-I levels and tumor shrinkage and secondarily classical cardiovascular risk factors (total/HDL-cholesterol ratio, glucose tolerance), blood pressure and drug tolerability. In LAR- and in LAN-treated patients, respectively: GH and IGF-I were controlled in 21 (77.7%) and in 16 patients (59.3%; p=0.26); tumor shrinkage was absent (<25%) in 4 and 5 patients (p=1), mild (25.1-50%) in 9 and 12 (p=0.57), moderate (50.1-75%) in 10 and 6 (p=0.37) and notable (>75%) in 4 and 4 patients (p=1). The total/HDL-cholesterol ratio and insulin levels significantly decreased while glucose levels significantly increased in both groups. None of the patients with normal glucose tolerance at diagnosis developed diabetes mellitus. Side effects were mostly at the gastrointestinal level and were similar with both drugs. In conclusion, newly diagnosed patients with acromegaly treated with LAR and LAN have no significantly different prevalence of disease control, tumor shrinkage, improvement of cardiovascular risk markers and side effects. Therefore, both drugs can be safely employed as first-line therapy of acromegaly.

GH and IGF-I excess control contributes to blood pressure control: results of an observational, retrospective, multicentre study in 105 hypertensive acromegalic patients on hypertensive treatment

CONTEXT

Approximately one-third of patients with acromegaly have concomitant hypertension. The outcome of hypertension after treatment of acromegaly is unknown.

OBJECTIVE

To evaluate the role of GH and IGF-I control on systolic (SBP) and diastolic blood pressure (DBP) levels.

PATIENTS

One hundred and five hypertensive patients (60 women, 45 men) with active disease receiving treatment for hypertension at their diagnosis of acromegaly.

DESIGN

Observational, retrospective, multicentre.

MEASUREMENTS

At diagnosis and after 24 months (median) of treatment we measured serum GH and IGF-I levels, blood pressure levels, left ventricular (LV) mass index (LVMi), early-to-late mitral flow velocity (E/A, as a measure of diastolic function) and LV ejection fraction (LVEF, as a measure of systolic function).

RESULTS

At the diagnosis of acromegaly, hypertension was mild in 41.1% and severe in 58.9%. Serum GH and IGF-I levels did not differ in patients with mild or severe hypertension. After 24 months of treatment, all patients had a notable decrease in both GH and IGF-I levels, and achieved significantly lower levels of DBP, heart rate and LVMi; 76 patients (71%) had achieved control of GH and IGF-I levels. Only the patients with controlled acromegaly achieved significantly lower SBP levels and significantly improved cardiac systolic and diastolic function. A higher dose of antihypertensive drugs and/or an increased number of drugs to control hypertension were significantly greater in patients with uncontrolled (32.3%) than in those with controlled acromegaly (7.8%; P = 0.004).

CONCLUSION

Hypertensive patients with controlled acromegaly achieved improved control of hypertension and of cardiac diastolic and systolic function. The use of antihypertensive drugs was significantly less in patients achieving control of acromegaly.

Assessment of the awareness and management of cardiovascular complications of acromegaly in Italy. The COM.E.T.A. (COMorbidities Evaluation and Treatment in Acromegaly) Study

BACKGROUND

During the course of acromegaly, cardiovascular, respiratory, and metabolic co-morbidities contribute to enhanced mortality. In 2002, the Pituitary Society and the European Neuroendocrine Association sponsored a Consensus Workshop in Versailles during which guidelines for diagnosis and treatment of co-morbidities in acromegaly were defined. However, as for other guidelines previously issued in the field, no data are available on their clinical application.

AIM

The aim of this work coordinated by the Italian Study group on co-morbidities evaluation and treatment in acromegaly (COM.E.T.A.) was to assess, on a national basis, the application in the clinical practice of the Versailles criteria for diagnosis and treatment of cardiovascular comorbities in acromegaly.

MATERIALS AND METHODS

In January 2007 an ad hoc designed questionnaire was sent by mail to 130 endocrine Centers in Italy.

RESULTS

The guidelines have been generally well perceived and translated in clinical practice. Specifically: 1) echocardiography is considered the mainstay for the diagnosis and follow-up; 2) ambulatory blood pressure monitoring and blood lipid assessment are performed in most hypertensive patients; 3) most endocrinologists directly manage hypertension and are aware of the uncertainty of the effect of the control of the disease on blood pressure levels; 4) ACE inhibitors and angiotensin receptors blockers are first-choice anti-hypertensive treatment; 5) approximately half of the centers consider somatostatin analogues of paramount relevance for biochemical control of disease; 6) awareness that left ventricular hypertrophy and heart failure are the most relevant cardiovascular complications is high although the impact of ischemic, arrhythmic, and valvular complications on prognosis is less well perceived.

CONCLUSION

The results of the present survey suggest that previuosly issued guidelines are generally carefully followed in the clinical practice. On the other side, a certain lack of awareness of emerging aspects of the cardiovascular comorbities of acromegaly confirms the necessity of periodically updating the guidelines based on the availability of new clinical information.

Epithelial sodium channel is a key mediator of growth hormone-induced sodium retention in acromegaly

Acromegalic patients present with volume expansion and arterial hypertension, but the renal sites and molecular mechanisms of direct antinatriuretic action of GH remain unclear. Here, we show that acromegalic GC rats, which are chronically exposed to very high levels of GH, exhibited a decrease of furosemide-induced natriuresis and an increase of amiloride-stimulated natriuresis compared with controls. Enhanced Na(+),K(+)-ATPase activity and altered proteolytic maturation of epithelial sodium channel (ENaC) subunits in the cortical collecting ducts (CCDs) of GC rats provided additional evidence for an increased sodium reabsorption in the late distal nephron under chronic GH excess. In vitro experiments on KC3AC1 cells, a murine CCD cell model, revealed the expression of functional GH receptors and IGF-I receptors coupled to activation of Janus kinase 2/signal transducer and activator of transcription 5, ERK, and AKT signaling pathways. That GH directly controls sodium reabsorption in CCD cells is supported by: 1) stimulation of transepithelial sodium transport inhibited by GH receptor antagonist pegvisomant; 2) induction of alpha-ENaC mRNA expression; and 3) identification of signal transducer and activator of transcription 5 binding to a response element located in the alpha-ENaC promoter, indicative of the transcriptional regulation of alpha-ENaC by GH. Our findings provide the first evidence that GH, in concert with IGF-I, stimulates ENaC-mediated sodium transport in the late distal nephron, accounting for the pathogenesis of sodium retention in acromegaly.

Acromegaly

Acromegaly is an acquired disorder related to excessive production of growth hormone (GH) and characterized by progressive somatic disfigurement (mainly involving the face and extremities) and systemic manifestations. The prevalence is estimated at 1:140,000-250,000. It is most often diagnosed in middle-aged adults (average age 40 years, men and women equally affected). Due to insidious onset and slow progression, acromegaly is often diagnosed four to more than ten years after its onset. The main clinical features are broadened extremities (hands and feet), widened thickened and stubby fingers, and thickened soft tissue. The facial aspect is characteristic and includes a widened and thickened nose, prominent cheekbones, forehead bulges, thick lips and marked facial lines. The forehead and overlying skin is thickened, sometimes leading to frontal bossing. There is a tendency towards mandibular overgrowth with prognathism, maxillary widening, tooth separation and jaw malocclusion. The disease also has rheumatologic, cardiovascular, respiratory and metabolic consequences which determine its prognosis. In the majority of cases, acromegaly is related to a pituitary adenoma, either purely GH-secreting (60%) or mixed. In very rare cases, acromegaly is due to ectopic secretion of growth-hormone-releasing hormone (GHRH) responsible for pituitary hyperplasia. The clinical diagnosis is confirmed biochemically by an increased serum GH concentration following an oral glucose tolerance test (OGTT) and by detection of increased levels of insulin-like growth factor-I (IGF-I). Assessment of tumor volume and extension is based on imaging studies. Echocardiography and sleep apnea testing are used to determine the clinical impact of acromegaly. Treatment is aimed at correcting (or preventing) tumor compression by excising the disease-causing lesion, and at reducing GH and IGF-I levels to normal values. Transsphenoidal surgery is often the first-line treatment. When surgery fails to correct GH/IGF-I hypersecretion, medical treatment with somatostatin analogs and/or radiotherapy can be used. The GH antagonist (pegvisomant) is used in patients that are resistant to somatostatin analogs. Adequate hormonal disease control is achieved in most cases, allowing a life expectancy similar to that of the general population. However, even if patients are cured or well-controlled, sequelae (joint pain, deformities and altered quality of life) often remain.

The long-term cardiovascular outcome of different GH-lowering treatments in acromegaly

The aim of this longitudinal study was to evaluate the echocardiographic outcome of acromegalic heart disease in patients undergoing different therapeutic approaches, in order to investigate whether SSA could provide therapeutic advantages as compared with neurosurgery. In total of 36, consecutive patients undergoing SSA treatment after neurosurgery were enrolled in this study (Gr.Surg.-SSA). After 12 months of treatment, 21 patients had a controlled disease, while the remaining 15 patients displayed uncontrolled disease. Twelve acromegalic patients who did not undergo SSA treatment due to controlled disease after neurosurgery were enrolled as control group (Gr.Surg). The echocardiographic-Doppler study was performed before neurosurgery and after 12-months of follow-up. After follow-up, a significant reduction in serum GH and IGF-I values, Left Ventricular Mass index (LVMi) and LVH rate with an improvement in diastolic function was observed in both groups of patients. We found a significant reduction of LVMi either in patients with controlled disease or in those with poorly controlled disease undergoing SSA treatment. Diastolic function and of LVH percentage improved in all groups, but significantly so only in controlled patients, no significant difference in any echocardiographic parameters and in the prevalence of the LVH rate were observed between the three groups of patients at the end of follow-up. Therefore, our data appear to show that for echographic parameters medical treatment additive beneficial effects is compared to neurosurgery alone. SSA also appears to contribute to the improvement of acromegalic cardiomyopathy also in patients who did not achieve biochemical control of the disease.

Resolution of acromegalic cardiomyopathy in mild acromegalic physical abnormality after short-term octreotide therapy

Congestive heart failure developed in a 42-year-old man who had very mild acromegalic features. Echocardiography showed a marked dilatation of the left ventricle and decreased systolic function. Laboratory examinations revealed the elevated levels of growth hormone and insulin-like growth factor-1 and pituitary microadenoma was demonstrated by magnetic resonance imaging. Although the extensive conventional medical treatment was ineffective, short-term addition of somatostatin analog, octreotide, rapidly improved his cardiac function. After discontinuation of octreotide, further improvement was observed with minimal residual diastolic dysfunction. All medical treatment could be stopped after successful trans-sphenoidal surgery. Early diagnosis and effective treatment is important to reverse the acromegalic cardiomyopathy.

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.

[Cardiac morphology and performance alterations and analysis of determinant factors of left ventricular hypertrophy in 40 patients with acromegaly]

Acromegaly has a high mortality rate due mainly to cardiovascular complications. The aim was to evaluate the determinant factors of left ventricular hypertrophy (LVH) and cardiac alterations in 40 acromegalic patients submitted to clinical-laboratorial studies and echocardiogram. The variables analyzed were age, sex, disease duration, arterial hypertension (AH), impaired glucose tolerance/DM, previous treatment with octreotide, GH and %IGF-I. Univaried analysis showed that patients with LVH were older (p= 0.031), had higher prevalence of AH (p= 0.009) and higher %IGF-I (p= 0.002), than those without LVH. Multivaried analysis showed AH and %IGF-I as determinants of LVH (p= 0.035 and p= 0.016). After dichotomizing of %IGF-I, a score was created and the frequency of LVH was 9%, 65%, 92% x 0, 1, 2; p< 0.0001. Prevalence of aortic ectasia was higher and valvar disease was smaller than reported in the literature. We conclude that AH and %IGF-I were determinants of LVH.

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.

[Acromegaly in elderly people]

Acromegaly is associated with increased morbidity and mortality. Cardiovascular complications are the major predictors of mortality. Age and duration of symptoms are the major determinants of acromegalic cardiopathy. Successful control of acromegaly reverse cardiovascular abnormalities. Herein, we review clinical, biological and histopathological findings in elderly people. Treatments and side effects in relation with aging are questioned.

Etiologic aspects and management of acromegaly

Acromegaly is a systemic disease with various etiologies. It can occur as a sporadic or, more rarely, as a familial disease. Numerous complications such as endocrine, cardiovascular, respiratory, metabolic, osteoarticular and neoplastic disturbances occur and must be taken into account when establishing a therapeutic strategy. For this reason, the decision as to a treatment modality of acromegaly must be followed by a thorough evaluation of the patient and once the diagnosis of complications is settled, adequate treatment should be instituted. Follow up of the patients requires periodical re-assessment of complications’ status.

Octreotide long-acting release (LAR): a review of its use in the management of acromegaly

Octreotide long-acting release (LAR) is a somatostatin analogue designed for once monthly intramuscular injection. As with endogenous somatostatin, octreotide LAR inhibits secretion of growth hormone (GH) as well as various other peptide hormones. In the treatment of acromegaly, octreotide LAR effectively controlled the secretion of GH and insulin-like growth factor-1 (IGF-1) in about 55-70% of patients (n > 100) who had previously been treated with somatostatin analogues, a similar degree of control to that observed with subcutaneous octreotide and lanreotide slow release (SR). Progressive control of serum levels of GH and IGF-1 was achieved with octreotide LAR in clinical studies of up to 4 years' duration. In addition, primary therapy with octreotide LAR provided effective control of GH and IGF-1 secretion, particularly in patients with a pretreatment GH level <20 microg/L. The percentage of patients achieving a target serum GH level of <2-2.5 micro g/L or normal IGF-1 levels was significantly greater with octreotide LAR 10, 20 or 30 mg every 28 days than with lanreotide SR 30 mg every 7-14 days in a large (n = 125) sequential, 6-month study, but was not significantly different between treatment groups in a small, randomised, nonblind, parallel group study of previously untreated patients. The volume of pituitary tumour shrinkage achieved with octreotide LAR or lanreotide SR was also similar ( approximate, equals 33% after 24 months). Acromegaly symptoms, such as headache, increased perspiration, paraesthesia, fatigue and osteoarthralgia were improved during treatment with octreotide LAR or lanreotide SR. Overall, octreotide LAR is generally well tolerated by most patients. The incidence of gastrointestinal symptoms is about 30% but, in most cases, events are transient and mild to moderate. Gallbladder abnormalities (sediment, sludge, microlithiasis and gallstones) can occur, but only 1% have become symptomatic to date. The prevalence of biliary abnormalities did not change after switching from subcutaneous octreotide, or from lanreotide SR, to octreotide LAR. Glucose metabolism can be affected by octreotide LAR in some patients; about 15% become hyperglycaemic, usually mild in severity. In summary, octreotide LAR controls GH and IGF-1 secretion in about 55-70% of patients with acromegaly. Octreotide LAR is administered intramuscularly every 28 days, offering improved patient compliance and convenience over three-times-daily subcutaneous octreotide. Long-term therapy provides progressive control of serum GH and IGF-1 levels, and is generally well tolerated by most patients. Thus, for the medical management of acromegaly, octreotide LAR is an effective, well tolerated and convenient treatment option.

Octreotide-induced bradycardia and heart block during surgical resection of a carcinoid tumor

Octreotide may be a life-saving treatment in the case of an acute carcinoid crisis, but when given as an i.v. bolus in larger doses, it may cause significant effects on the cardiac conduction system. We describe cardiac conduction impairment observed during octreotide administration in a patient undergoing carcinoid tumor surgery. In this patient, i.v. boluses of 100 microg of octreotide resulted in symptomatic bradycardia, Mobitz type II atrioventricular block, and complete heart block. Perioperative physicians especially need to be aware of these potential effects because they may be more likely to occur during surgery because of the larger doses and boluses that are used to treat acute symptoms secondary to tumor manipulation.

IMPLICATIONS

In some susceptible patients, i.v. bolus administration of octreotide may cause significant bradycardia and cardiac conduction defects. Therefore, when octreotide is administered as a bolus, it may be advisable to give it slowly while monitoring the electrocardiogram.

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.

The role of somatostatin receptors in the medical treatment of acromegaly

Somatostatin is a hypothalamic inhibitor of pituitary growth hormone secretion and cell proliferation, binding to five distinct receptor subtypes (sstr1-5). Since native somatostatin has a short half-life, somatostatin analogues with a longer half-life have been developed for therapeutic purposes. Octreotide and lanreotide are currently available for treatment of acromegaly, binding with high-affinity sstr2 and sstr5. Octreotide, the first somatostatin analogue used in the medical therapy of acromegaly, was initially given subcutaneously at doses of 100-500 microg three times daily. The introduction of new depot formulations, such as octreotide long-acting release, slow-release lanreotide and lanreotide-autogel, improved patients compliance of long-term therapy, overcoming the inconvenience of multiple daily administration. The treatment with somatostatin analogues induces biochemical control and tumour shrinkage in about 50-70% and 30-60% of patients with acromegaly, respectively. However, the efficacy of this therapy lies on an adequate expression of sstr2 and sstr5 on tumor cells. In the past, somatostatin receptor expression was tested in vivo by (111)In-diethylenetriaminepentaacetate-D-Phe-octreotide scintigraphy: this method has been abandoned since normal pituitary tissue can be visualised by (111)In-diethylenetriaminepentaacetate-D-Phe-octreotide scintigraphy. Currently, the somatostatin receptorial profile can be characterised by autoradiography, molecular biology techniques and immunohistochemistry on surgically removed tumor tissue. These methods may offer an individualised approach sparing patients from unnecessary treatment.

Improvement of ventricular arrhythmia by octreotide treatment in acromegalic cardiomyopathy

We report a case of acromegalic cardiomyopathy in a 46-year-old Japanese man with pituitary adenoma. Increased secretion of growth hormone and insulin-like growth factor I were detected. He had left ventricular hypertrophy, impaired cardiac function, and frequent ventricular premature complexes. After 2-month treatment with octreotide, a long-acting somatostatin analogue, levels of both hormones were decreased. At the same time, left ventricular hypertrophy (intraventricular septal thickness: 22.5 to 17.8 mm), cardiac function (ejection fraction: 38 to 50%), and frequency of ventricular premature complexes (17,249 to 2,882 beats a day) were improved. Transsphenoidal surgery was then safely performed. Treatment with octreotide is thought to have some effect on improvement of ventricular arrhythmia in acromegalic heart.

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.

The Effects of Octreotide in Dilated Cardiomyopathy: An Open-label Trial in 12 Patients

Octreotide, a somatostatin analogue, has been found effective in the treatment of acromegalic cardiomyopathy. We investigated whether intermittent octreotide therapy had beneficial effects in patients with ischemic or idiopathic dilated cardiomyopathy, which are refractory to conventional therapy. Twelve patients with ischemic or idiopathic dilated cardiomyopathy were enrolled in the study. In addition to conventional treatment, octreotide (first 50 microg and then 25 microg three times per day for 4 days) was administered and repeated after 1, 2, and 3 months. The patients were evaluated 3 times, before and immediately after the first treatment and after 3 months of treatment, using echocardiography, exercise stress testing, ambulatory ECG, right ventricular catheterization, cardiac enzymes, and the Minnesota living with heart failure questionnaire for quality of life. There were no significant changes in parameters after the first treatment. However, after 3 months of treatment, there were significant improvements in the left ventricular ejection fraction, left ventricular posterior wall thickness, hemodynamics, exercise capacity, and quality of life. Additionally, ischemic burden and the number of ventricular premature beats also decreased slightly. Intermittent octreotide therapy led to significant improvements in patients with ischemic and idiopathic dilated cardiomyopathy refractory to conventional treatment. We believe that this therapy should be attempted as an adjunctive therapy in these patients, and that in this respect, randomized, double-blind, clinical, and large-scale studies are required before regular usage is undertaken.

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.

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.

Acromegaly: historical perspectives and current therapy

Soon after the initial description of acromegaly in the late 19th century, neurosurgeons performed the first operative procedures for the disease. Transcranial procedures eventually yielded to the transsphenoidal approach. Reasonably effective medical therapy was introduced in the 1970s and pharmacological progress continues to be realized. It is now recognized that excess growth hormone is associated with significant morbidity and mortality and that biochemical remission improves outcome. Although medical and radiation treatments offer useful adjuncts, surgery provides optimal results.

Marked improvement in cardiovascular function after successful transsphenoidal surgery in acromegalic patients

OBJECTIVE

Transsphenoidal surgery results in biochemical remission of acromegaly in 45-80% of patients; however, few studies have addressed the impact of transsphenoidal surgery on cardiovascular function in acromegalic patients. The aim of this prospective study was to investigate the effects of postoperative GH/IGF-I normalization on echocardiographic parameters and blood pressure (BP) in a series of patients with active acromegaly.

DESIGN

An open prospective study.

PATIENTS

Thirty newly diagnosed acromegalic patients undergoing transsphenoidal surgery.

MEASUREMENTS

Doppler echocardiography and 24-h ambulatory blood pressure monitoring were performed before and 6 months after transsphenoidal surgery.

RESULTS

Fifteen patients were considered to be well controlled postoperatively (group A), as defined by normal age-corrected IGF-I levels and glucose-suppressed GH levels less than 2 mU/l, the remaining 15 patients being considered as poorly controlled (group B). In group A, a postoperative decrease of left ventricular mass index was observed (104.4 +/- 6.6 vs. 127.1 +/- 7.7 g/m2; P < 0.001), associated with an improvement of some indices of diastolic function, such as an increase of the early/late transmitral peak flow velocity (P < 0.05) and a decrease of isovolumic relaxation time (P < 0.01). No significant change was observed in group B. A significant decrease of 24-h systolic BP was also observed in group A (P < 0.05) and five of six patients normalized their BP circadian rythm. In contrast, a nonsignificant increase in BP values, with a persistent blunted BP profile where present, was observed in group B.

CONCLUSIONS

We conclude that successful transsphenoidal surgery is able to induce a significant improvement in some cardiac parameters and a slight reduction in systolic blood pressure in acromegalic patients.

Increased arterial intima-media thickness by B-M mode echodoppler ultrasonography in acromegaly

BACKGROUND

Patients with acromegaly have an increased morbidity and mortality for cardiovascular diseases. Despite the increasing evidence for the existence of a specific cardiomyopathy in acromegaly, the presence of vascular abnormalities has been never investigated.

OBJECTIVE

To evaluate the cardiovascular risk and premature atherosclerosis in acromegaly.

SUBJECTS

Forty-five patients with acromegaly and 30 sex- and age-matched healthy subjects were included in this study: 30 patients were studied at the diagnosis of acromegaly and were in active disease (GH 59.3 +/- 10.2 mU/l, IGF-I 733 +/- 57.6 microg/l) while 15 patients were studied after surgery and/or radiotherapy and were cured from the disease (GH 4.5 +/- 0.7 mU/l, IGF-I 172.4 +/- 16.9 microg/l).

METHODS

Body mass index (BMI), systolic (SBP) and diastolic blood pressure (DBP), serum total, LDL- and HDL-cholesterol, triglycerides, and fibrinogen levels, prothrombin time (PT), activated partial thromboplastin time (APTT), glucose and insulin levels (fasting and after glucose load) were measured in all patients and controls. By echodoppler ultrasonography, blood systolic (SPV) and diastolic (DPV) peak velocity, and resistance index (RI) were measured at both common and internal carotid arteries where presence, size and location of atherosclerotic plaques were evaluated by B-Mode ultrasonography. Intima-media thickness (IMT) of both common carotids was measured by M-Mode ultrasonography.

RESULTS

SBP, but not DBP, was significantly higher in patients with active disease than in cured patients and controls (P = 0.003). Hypertension was found in nine (30%) patients with active disease, in two (13.3%) of those cured from acromegaly and in none of controls (chi2 = 10.81, P < 0.004). Fasting blood glucose levels were significantly higher both in patients with active disease and in those cured from the disease than in controls (P < 0.001). Circulating insulin levels were significantly higher in patients with active disease than in cured patients and controls (P < 0.001) and in cured patients than in controls (P < 0.001). Glucose tolerance abnormalities were found in 13 (43.3%) patients with active disease, in four (26.6%) patients with inactive disease and in four controls (13.3%) (chi2 = 6.71, P = 0.03). Total blood cholesterol levels were similar in the three groups, LDL-cholesterol and triglycerides levels were significantly higher, whereas HDL-cholesterol levels were significantly lower both in patients with active disease and in those cured from the disease than in controls (P < 0.001). Serum fibrinogen levels were significantly higher both in patients with active disease and in those cured from the disease than in controls (P < 0.001). No difference was found in PT and APTT levels among the three groups. At the level of right and left common carotid arteries, IMT was significantly higher both in patients with active disease and in those cured from the disease than in controls (P < 0.001). Both right and left SPV, but not DPV, were significantly higher in patients with active disease than in those cured from the disease and in controls (P < 0.01). Well defined carotid wall plaques were detected in two patients (6.6%) with active disease, in one patient cured from the disease (6.6%) and in two controls (6.6%). At the level of right and left internal carotid arteries, SPV, DPV and RI were similar among the three groups. Well defined carotid wall plaques were detected in three patients with active disease (10%), two patients cured from the disease (13.3%) and in one control (3.3%).

CONCLUSIONS

A significant increase of IMT of both common carotid arteries was observed in patients with active acromegaly, this was also found in those cured from acromegaly. However, the prevalence of well defined carotid plaques was not increased in both groups of patients with acromegaly as compared to controls. On this basis, heart more than vessels seems to be affected by chronic GH and IGF-I excess in 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.

[Biventricular impairment of diastolic function in acromegaly]

AIM

Left ventricle impairment is very common in acromegaly. Concentric hypertrophy and diastolic dysfunction are observed at an early stage. Late left ventricle dilatation with systolic dysfunction may appear. Few reports have studied right ventricle diastolic function.

METHODS

Twenty-seven acromegalic patients were included. Biventricular diastolic function was assessed using Doppler-echocardiography. Possible associations with hormonal activity, evolution time of illness, hypertension, left ventricular hypertrophy and systolic impairment on echocardiography were studied.

RESULTS

Fifteen patients showed left ventricular diastolic dysfunction, whereas thirteen patients showed right ventricular diastolic dysfunction. A good correlation was observed between E/A relation of both ventricles (r = 0.70; p < 0.01) and isovolumetric relaxation time (r = -0.60; p < 0.01). The right ventricular E/A relation correlated with left ventricular mass index and significance was almost achieved with the presence of hypertension. There was no statistical correlations between the right ventricular E/A relation and hormone values or evolution time of illness. The left ventricular E/A relation showed a significant association with left ventricular mass index, isovolumetric time index and evolution time of illness. There were no statistical association with hormone values.

CONCLUSIONS

The high prevalence of right ventricular diastolic dysfunction observed in acromegaly suggests the presence of acromegalic myocardiopathy.