Dilated cardiomyopathy in a patient with acromegaly – association or causality

Abstract

Background. Acromegaly is a rare endocrine disorder that carries a significant burden of cardiovascular morbidity and mortality. Abnormalities of the growth hormone/insulin-like growth factor-1 (IGF-1) axis in acromegaly lead to the characteristic cardiovascular manifestations. One hallmark feature of the disease is acromegalic cardiomyopathy; a syndrome of progressive cardiac dysfunction characterized by left ventricular (LV) hypertrophy, diastolic dysfunction, and combined systolic and diastolic dysfunction in advanced stages. Dilated cardiomyopathy (DCM) is relatively rare in this setting but is associated with increased mortality. Case report. We report the case of a 44 y.o man who was admitted to the cardiology department because of progressive dyspnea on exertion and paroxysmal nocturnal dyspnea with recent onset. Physical examination revealed systolic murmurs in mitral and tricuspid areas and jugular vein distension. Laboratory findings showed moderate hepatic cytolysis. Electrocardiogram showed sinus rhythm (SR) and LV hypertrophy. Echocardiography revealed DCM with severe LV dysfunction (LV ejection fraction (LVEF) = 20%), LV hypertrophy, restrictive diastolic dysfunction, biatrial enlargement, moderate mitral regurgitation and pulmonary hypertension (systolic pulmonary artery pressure (PAPs) = 60 mmHg). A coronary angiography was performed to rule out coronary disease. It revealed normal coronary arteries. Optimal heart failure (HF) treatment was started. The patient did not attend follow-up visits. Ten years later, he presented with NYHA class III HF symptoms. Mandibular enlargement with widened space between the lower incisor teeth, macroglossia, enlargement of his hands and feet over the last 10 years was noted on physical examination. Laboratory findings revealed hepatic cytolysis and elevated NT-proBNP (9668 pg/ml). Electrocardiogram identified atrial fibrillation. Echocardiography showed dilated cardiomyopathy with further deterioration of LV function (LVEF=15%) and pulmonary hypertension. Magnetic resonance imaging showed non-specific LV myocardial fibrosis. Genetic tests, carried out to exclude a genetic DCM (170 genes evaluated), did not identify any pathogenic variants. At this point an endocrinology evaluation was requested. It revealed active acromegaly (IGF-I = 416 ng/ml) due to pituitary microadenoma. Considering a high surgical risk, conservative treatment with somatostatin analogue was initiated. Follow up at 5, 10 and 18 months revealed improved clinical status, spontaneous restauration of SR, progressive improvement in LVEF (30%, 33% and 40%), normalization of PAPs and of NT-proBNP = 186 pg/ml. Conclusions. Here we report the case of a patient with acromegaly and severe non-ischemic DCM. Treatment with somatostatin analogue resulted in early improvement of clinical status and LV systolic function sustaining a probable causal relation between endocrinological dysfunction and DCM. This is a one of the few reported cases of acromegalic DCM with significant improvement under somatostatin analogue therapy as an initial option.