Heart failure (HF) has been associated with chronic deleterious effects on skeletal muscle, endocrine system, vasculature and sympathetic nervous system. These alterations have a significant impact on quality of life, leading to a reduction in functional capacity and limited symptoms, which involve dyspnea and fatigue. The investigators tested the hypothesis that hormonal anabolic deficiency associated with neurovascular alterations may worsen the prognosis of patients with heart failure.
One hundred and fifty six patients have been enrolled so far. Methods were as described below: * Muscle sympathetic nerve activity (MSNA) was directly recorded from the peroneal nerve using the microneurography technique ; * All patients underwent symptom-limited cardiopulmonary exercise test performed on a cycle ergometer, using a ramp protocol with workload increments of 5 or 10 Watts per minute; * Body composition measurements were performed using dual-energy X-ray absorptiometry (DXA); * Muscle strength was assessed by handgrip dynamometer using the mean value of three attempts; * Blood samples were drawn in the morning after 12h overnight fasting. The laboratory tests included B-type natriuretic peptide (BNP; pg/mL) plasma level, serum sodium (mEq/L), serum potassium (mEq/L), creatinine (mg/dL), haemoglobin level (g/dL), high-sensitivity C-reactive protein (CRP; mg/L), lipid profile (triglyceride, total cholesterol, high-density lipoprotein, and low-density lipoprotein; mg/dL), and fasting glucose (mg/dL). Blood sample to assess hormone plasma levels were also drawn at the same time: total testosterone (TT), free testosterone (FT), sex hormone binding globulin (SHBG), dehydroepiandrosterone sulfate (DHEAS), luteinizing hormone (LH), follicle-stimulating hormone (FSH), thyroid stimulating hormone (TSH) and insulin-like growth factor 1 (IGF1).
Study Type
OBSERVATIONAL
Enrollment
169
Oxygen consumption (VO2) and carbon dioxide output (VCO2) were measured by means of gas exchange on a breath-by-breath basis. The patients were initially monitored for 2 minutes at rest when seated on the ergometer, after that they were instructed to pedal at a pace of 60-70 rpm and the completion of the test occurred when, in spite of verbal encouragement, the patient reached maximal volitional fatigue.
Multiunit post-ganglionic muscle sympathetic nerve recordings were made using a tungsten microelectrode placed in the peroneal nerve near the fibular head. Nerve signals were amplified by a factor of 50,000 to 100,000 and band-pass filtered (700 to 2000 Hz). For recording and analysis, nerve activity was rectified and integrated (time constant 0.1 seconds) to obtain a mean voltage display of sympathetic nerve activity.
Instituto do Coração do Hospital da Clínicas da Universidade de Sao Paulo
São Paulo, São Paulo, Brazil
Impact of testosterone deficiency on mortality
Blood sample was collected in the morning (between 8:00-10:00 a.m.) after 12 hours fasting.
Time frame: 2 years
Impact of muscle sympathetic nerve activity on mortality
Microneurography was used to assess the sympathetic nervous system.
Time frame: 2 years
Impact of neurovascular alterations on mortality
Venous occlusion pletysmography was used to evaluate vasodilation.
Time frame: 2 years
Impact of testosterone deficiency on body composition
Body composition measurements were performed using dual-energy X-ray absorptiometry.
Time frame: 2 years
Impact of testosterone deficiency on functional capacity
All patients underwent symptom-limited cardiopulmonary exercise test to measure functional capacity.
Time frame: 2 years
Impact of testosterone deficiency on strength
Muscle strength was assessed by handgrip dynamometer using the mean value of three attempts.
Time frame: 2 years
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Dual-energy X-ray absorptiometry (DXA) scan was used to measure total lean mass, body fat and bone mineral content.
Venous occlusion plethysmography was used to assess non-invasively blood flow.
Blood samples were drawn in the morning after 12h overnight fasting.
Muscle strength was assessed by handgrip dynamometer using the mean value of three attempts.