Citations

Background— Oxidative stress may contribute to heart failure (HF) progression. Inhibiting xanthine oxidase in hyperuricemic HF patients may improve outcomes. Methods and Results— We randomly assigned 253 patients with symptomatic HF, left ventricular ejection fraction ≤40%, and serum uric acid levels ≥9.5 mg/dL to receive allopurinol (target dose, 600 mg daily) or placebo in a double-blind, multicenter trial. The primary composite end point at 24 weeks was based on survival, worsening HF, and patient global assessment. Secondary end points included change in quality of life, submaximal exercise capacity, and left ventricular ejection fraction. Uric acid levels were significantly reduced with allopurinol in comparison with placebo (treatment difference, –4.2 [–4.9, –3.5] mg/dL and –3.5 [–4.2, –2.7] mg/dL at 12 and 24 weeks, respectively, both P <0.0001). At 24 weeks, there was no significant difference in clinical status between the allopurinol- and placebo-treated patients (worsened 45% versus 46%, unchanged 42% versus 34%, improved 13% versus 19%, respectively; P =0.68). At 12 and 24 weeks, there was no significant difference in change in Kansas City Cardiomyopathy Questionnaire scores or 6-minute walk distances between the 2 groups. At 24 weeks, left ventricular ejection fraction did not change in either group or between groups. Rash occurred more frequently with allopurinol (10% versus 2%, P =0.01), but there was no difference in serious adverse event rates between the groups (20% versus 15%, P =0.36). Conclusions— In high-risk HF patients with reduced ejection fraction and elevated uric acid levels, xanthine oxidase inhibition with allopurinol failed to improve clinical status, exercise capacity, quality of life, or left ventricular ejection fraction at 24 weeks. Clinical Trial Registration— URL: http://www.clinicaltrials.gov . Unique identifier: NCT00987415.

Background— Early studies showed beneficial effects of phosphodiesterase 5 inhibitors on cardiovascular function in heart failure (HF) patients, but the RELAX trial observed no improvement in exercise capacity with sildenafil treatment in subjects with HF and preserved ejection fraction. Methods and Results— A subgroup of participants in the RELAX trial (n=48) underwent comprehensive noninvasive cardiovascular assessment before and after treatment with sildenafil or placebo in a prospective ancillary study. Left ventricular contractility was assessed by peak power index and stroke work index. Systemic arterial load was assessed by arterial elastance (Ea) and right ventricular afterload by pulmonary artery systolic pressure. Endothelial function was assessed by reactive hyperemia index after upper arm cuff occlusion. Compared with placebo (n=25), sildenafil (n=23) decreased Ea (−0.29±0.28 mm Hg/mL versus +0.02±0.29, P =0.008) and tended to improve reactive hyperemia index (+0.30±0.45 versus −0.17±0.30, P =0.054). In contrast, left ventricular contractility was reduced by 11% to 16% with sildenafil compared with placebo (ΔPWR/EDV −52±70 versus +0±40 mm Hg/s, P =0.006; ΔSW/EDV +0.3±5.8 versus −6.0±5.1 mm Hg, P =0.04). Sildenafil had no effect on pulmonary artery systolic pressure. Conclusions— In subjects with HF and preserved ejection fraction, sildenafil displayed opposing effects on ventricular and vascular function. We speculate that beneficial effects of phosphodiesterase 5 inhibitors in the systemic vasculature and endothelium were insufficient to improve clinical status or that the deleterious effects on left ventricular function offset any salutary vascular effects, contributing to the absence of benefit observed with sildenafil in subjects with HF and preserved ejection fraction in the RELAX trial. Clinical Trial Registration— URL: http://www.clinicaltrials.gov . Unique identifier: NCT00094302.

Background— Atrial fibrillation (AF) is common among patients with heart failure and preserved ejection fraction (HFpEF), but its clinical profile and impact on exercise capacity remain unclear. RELAX (Phosphodiesterase-5 Inhibition to Improve Clinical Status and Exercise Capacity in HFpEF) was a multicenter randomized trial testing the impact of sildenafil on peak V O 2 in stable outpatients with chronic HFpEF. We sought to compare clinical features and exercise capacity among patients with HFpEF who were in sinus rhythm (SR) or AF. Methods and Results— RELAX enrolled 216 patients with HFpEF, of whom 79 (37%) were in AF, 124 (57%) in SR, and 13 in other rhythms. Participants underwent baseline cardiopulmonary exercise testing, echocardiogram, biomarker assessment, and rhythm status assessment before randomization. Patients with AF were older than those in SR but had similar symptom severity, comorbidities, and renal function. β-blocker use and chronotropic indices were also similar. Despite comparable left ventricular size and mass, AF was associated with worse systolic (lower EF, stroke volume, and cardiac index) and diastolic (shorter deceleration time and larger left atria) function compared with SR. Pulmonary artery systolic pressure was higher in AF. Patients with AF had higher N-terminal pro-B-type natriuretic peptide, aldosterone, endothelin-1, troponin I, and C-telopeptide for type I collagen levels, suggesting more severe neurohumoral activation, myocyte necrosis, and fibrosis. Peak V O 2 was lower in AF, even after adjustment for age, sex, and chronotropic response, and V E /V CO 2 was higher. Conclusions— AF identifies an HFpEF cohort with more advanced disease and significantly reduced exercise capacity. These data suggest that evaluation of the impact of different rate or rhythm control strategies on exercise tolerance in patients with HFpEF and AF is warranted. Clinical Trial Registration— URL: http://www.clinicaltrials.gov . Unique identifier: NCT00763867.