Cardiovascular disease is the primary cause of death in patients with end stage renal disease (ESRD). New research suggests that the high risk of death may be partly due to high levels of fibrosis and a loss of small blood vessels in the heart of patients with dialysis-dependent ESRD. This study is designed to compare the effects of two different drugs, spironolactone and L-arginine, with placebo on structure and function of the heart in individuals with dialysis-dependent ESRD.
We hypothesize that that abnormalities in aldosterone and nitric oxide (NO) homeostasis contribute to the progression of microvascular disease and myocardial fibrosis in ESRD and that agents designed to restore normal aldosterone and NO homeostasis will improve microvascular and diastolic cardiac function in the heart of individuals with dialysis dependent ESRD. We will test 2 specific agents: The mineralocorticoid receptor blocker spironolactone; and L-arginine, an agent which improves NO bioavailability. Two specific aims will be addressed using a prospective, double-blinded, 2x2 factorial trial in dialysis dependent patients with ESRD. Subjects will be randomized to placebo, spironolactone plus placebo, L-arginine plus placebo, or combination spironolactone and L-arginine therapy. Diastolic cardiac function will be assessed using tissue Doppler index (TDI) determined mitral annular velocities (E') on LV echocardiography, and microvascular supply will be assessed using CFR-the ratio of hyperemic to resting myocardial blood flow-measured by positron emission tomography (PET) scans at baseline, 2 weeks and after 9 months of randomized therapy. This randomized trial of spironolactone and L-arginine will provide important data about the contributions of aldosterone and NO to the pathogenesis of cardiovascular disease in ESRD, will demonstrate the therapeutic potential of L-arginine and spironolactone as as targeted cardiovascular therapies for use in ESRD, and will provide important insights into the underlying pathophysiology of cardiovascular disease in ESRD. The results generated will provide the data needed to design large-scale trials testing whether spironolactone or L-arginine can improve mortality or cardiovascular outcomes in ESRD.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
QUADRUPLE
Massachusetts General Hospital
Boston, Massachusetts, United States
Brigham & Women's Hospital
Boston, Massachusetts, United States
Beth Israel Deaconess Medical Center
Boston, Massachusetts, United States
Change in coronary Flow Reserve (PET)
Coronary flow reserve will be measured using rest and stress 13N ammonia myocardial positron emission tomography (PET) at baseline and 9 months
Time frame: Between baseline and 9 months
Change in left ventricular diastolic function
Left ventricular diastolic function will be measured using mitral annular E' on tissue doppler index echocardiography at baseline and 9 months
Time frame: Between baseline and 9 months
Association between coronary flow reserve (CFR) and tissue doppler index (E')
Time frame: Baseline
Change in resting myocardial blood flow
Time frame: Between baseline and 9 months
Change in left ventricular mass index
Time frame: Between baseline and 9 months
Change in coronary vascular resistance
Time frame: Between 0 and 9 months
Association between change in coronary flow reserve (CFR) and change in diastolic function-tissue doppler index (E')
Time frame: Between baseline and 9 months
Change in early diastolic function (E')
Time frame: Between baseline and 2 weeks
Combined cardiovascular safety
Combined rate of death, myocardial infarction, stroke, or hospitalization
Time frame: Up to 9 months
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Cardiovascular death
Time frame: Up to 9 months
Hyperkalemia
Hyperkalemia requiring extra dialysis, adjustment in dialysate potassium, or discontinuation of therapy
Time frame: Up to 9 months
Hypotension
Symptomatic or intradialytic hypotension up to 9 months
Time frame: Up to 9 months
Change in early coronary flow reserve
Time frame: Between baseline and 2 weeks
Change in hyperemic myocardial blood flow
Time frame: Between baseline and 9 months