Pulmonary Vasculature Responsiveness to Phosphodiesterase-5A Inhibition in Heart Failure With Reduced Ejection Fraction: Possible Role of Plasma Potassium.

Introduction: Phosphodiesterase-5a inhibition (PDE5i) leads to favorable changes in pulmonary hemodynamic and cardiac output (CO) in patients with advanced heart failure (HF) and reduced ejection fraction (HFrEF). The hemodynamic response to PDE5i could be heterogeneous and the clinical variables associated with these changes are scarcely investigated. Materials and Methods: Of 260 patients with advanced HFrEF referred for advanced therapies [cardiac transplant/left ventricular assist device (LVAD)], 55 had pulmonary hypertension (PH) and fulfilled the criteria for the PDE5i vasoreactivity test. Right heart catheterization (RHC) was performed as a part of clinical evaluation before and after 20-mg intravenous sildenafil. Absolute and relative changes in pulmonary vascular resistance (PVR) were evaluated to assess hemodynamic response to PDE5i. Clinical, biochemical, and hemodynamic factors associated with PVR changes were identified. Results: Sildenafil administration reduced PVR (- 45.3%) and transpulmonary gradient (TPG; - 34.8%) and increased CO (+ 13.6%). Relative change analysis showed a negative moderate association between baseline plasma potassium and changes in PVR (r = - 0.48; p = 0.001) and TPG (r = - 0.43; p = 0.005) after PDE5i. Aldosterone concentration shows a direct moderate association with PVR changes after PDE5i. A significant moderate association was also demonstrated between CO improvement and the severity of mitral (r = 0.42; p = 0.002) and tricuspid (r = 0.39; p = 0.004) regurgitation. Conclusion: We identified plasma potassium, plasma aldosterone level, and atrioventricular valve regurgitations as potential cofounders of hemodynamic response to acute administration of PDE5i. Whether modulation of potassium levels could enhance pulmonary vasoreactivity in advanced HFrEF deserves further research.

Switching to riociguat versus maintenance therapy with phosphodiesterase-5 inhibitors in patients with pulmonary arterial hypertension (REPLACE): a multicentre, open-label, randomised controlled trial.

BACKGROUND: Riociguat and phosphodiesterase-5 inhibitors (PDE5i), approved for the treatment of pulmonary arterial hypertension (PAH), act on the same pathway via different mechanisms. Riociguat might be an alternative option for patients with PAH who do not respond sufficiently to treatment with PDE5i, but comparisons of the potential benefits of riociguat and PDE5i in these patients are needed. The aim of this trial was to assess the effects of switching to riociguat from PDE5i therapy versus continued PDE5i therapy in patients with PAH at intermediate risk of 1-year mortality. METHODS: Riociguat rEplacing PDE5i therapy evaLuated Against Continued PDE5i thErapy (REPLACE) was an open-label, randomised controlled trial in 81 hospital-based pulmonary hypertension centres in 22 countries. The study enrolled patients aged 18-75 years with symptomatic PAH at intermediate risk of 1-year mortality (based on the European Society for Cardiology-European Respiratory Society guideline thresholds for WHO functional class and 6-min walk distance [6MWD]) who were receiving treatment with a PDE5i with or without an endothelin receptor antagonist for at least 6 weeks before randomisation. Patients were excluded if they had been previously treated with riociguat, had used prostacyclin analogues or prostacyclin receptor agonists within 30 days before randomisation, had clinically significant restrictive or obstructive parenchymal lung disease, or had left heart disease. Patients were randomly assigned (1:1) to remain on PDE5i treatment (oral sildenafil [≥60 mg per day] or oral tadalafil [20-40 mg per day]; the PDE5i group) or to switch to oral riociguat (up to 2·5 mg three times per day; the riociguat group), using an interactive voice and web response system, stratified by cause of PAH. The primary endpoint was clinical improvement by week 24, defined as an absence of clinical worsening and prespecified improvements in at least two of three variables (6MWD, WHO functional class, and N-terminal prohormone of brain natriuretic peptide), analysed using last observation carried forward in all randomly assigned patients with observed values at baseline and week 24 who received at least one dose of study medication (the full analysis set). Secondary endpoints included clinical worsening events. The trial has been completed and is registered with ClinicalTrials.gov, NCT02891850. FINDINGS: Between Jan 11, 2017, and July 31, 2019, 293 patients were screened, of which 226 patients were randomly assigned to the riociguat group (n=111) or to the PDE5i group (n=115). 211 patients completed the study and 14 patients discontinued (seven in each group). One patient assigned to the PDE5i group did not receive treatment, so 225 patients were included in the safety analysis, and one further patient in the PDE5i group had missing components of the composite primary endpoint at baseline, so 224 patients were included in the full analysis set. The primary endpoint was met by 45 (41%) of 111 patients in the riociguat group and 23 (20%) of 113 patients in the PDE5i group; odds ratio [OR] 2·78 (95% CI 1·53-5·06; p=0·0007). Clinical worsening events occurred in one (1%) of 111 patients in the riociguat group (hospitalisation due to worsening PAH) and 10 (9%) of 114 patients in the PDE5i group (hospitalisation due to worsening PAH [n=9]; disease progression [n=1]; OR 0·10 [0·01-0·73]; p=0·0047). The most frequently occurring adverse events were hypotension (15 [14%]), headache (14 [13%]), and dyspepsia (10 [9%]) in the riociguat group, and headache (eight [7%]), cough (seven [6%]), and upper respiratory tract infection (seven [6%]) in the PDE5i group. Serious adverse events were reported in eight (7%) of 111 patients in the riociguat group and 19 (17%) of 114 patients in the PDE5i group. During the study, four patients died in the PDE5i group, one of them during the safety follow-up period. INTERPRETATION: Switching to riociguat from PDE5i treatment, both of which act via the nitric oxide-soluble guanylate cyclase-cyclic guanosine monophosphate pathway, could be a strategic option for treatment escalation in patients with PAH at intermediate risk of 1-year mortality. FUNDING: Bayer AG, Merck Sharp & Dohme.

Acute Unloading Effects of Sildenafil Enhance Right Ventricular-Pulmonary Artery Coupling in Heart Failure.

BACKGROUND: Phosphodiesterase-5A inhibitors (PDE5i) are sometimes used in patients with advanced heart failure with reduced ejection fraction before heart transplant or left ventricular assist device implantation to decrease right ventricular (RV) afterload and mitigate the risk of right heart failure. Conflicting evidence exists regarding the impact of these drugs on RV contractility. The aim of this study was to explore the acute effects of PDE5i on ventricular-vascular coupling and load-independent RV contractility. METHODS: Twenty-two patients underwent right heart catheterization and gated equilibrium blood pool single photon emission computed tomography, before and after 20 mg intravenous sildenafil. Single photon emission computed tomography and right heart catheterization-derived data were used to calculate RV loading and contractility. RESULTS: PDE5i induced a decrease in the right atrial pressure (-43%), pulmonary artery (PA) mean pressure (-26%), and PA wedge pressure (PAWP; -23%), with favorable reductions in pulmonary vascular resistance (-41%) and PA elastance (-40%), and increased cardiac output (+13%) (all P < 0.01). The RV ejection fraction increased with sildenafil (+20%), with no change of RV contractility (P = 0.74), indicating that the improvement in the RV ejection fraction was related to enhanced RV-PA coupling (r = 0.59, P = 0.004) by a decrease in the ventricular load. RV diastolic compliance increased with sildenafil. The decrease in the PAWP correlated with RV end-diastolic volume decrease; no relationship was observed with the change in LV transmural pressure, suggesting decreased pericardial constraint. CONCLUSIONS: Acute PDE5i administration has profound RV afterload-reducing effects, improves the RVEF, decreases RV volumes, and decreases the PAWP, predominantly through relief of pericardial constraint, without effects on RV chamber contractility. These findings support further study of PDE5i in protection of RV function in advanced heart failure with reduced ejection fraction who are at risk of RV failure.

Hyperuricemia treatment in acute heart failure patients does not improve their long-term prognosis: A propensity score matched analysis from the AHEAD registry.

BACKGROUND: Hyperuricemia is associated with a poorer prognosis in heart failure (HF) patients. Benefits of hyperuricemia treatment with allopurinol have not yet been confirmed in clinical practice. The aim of our work was to assess the benefit of allopurinol treatment in a large cohort of HF patients. METHODS: The prospective acute heart failure registry (AHEAD) was used to select 3160 hospitalized patients with a known level of uric acid (UA) who were discharged in a stable condition. Hyperuricemia was defined as UA ≥500 µmoL/L and/or allopurinol treatment at admission. The patients were classified into three groups: without hyperuricemia, with treated hyperuricemia, and with untreated hyperuricemia at discharge. Two- and five-year all-cause mortality were defined as endpoints. Patients without hyperuricemia, unlike those with hyperuricemia, had a higher left ventricular ejection fraction, a better renal function, and higher hemoglobin levels, had less frequently diabetes mellitus and atrial fibrillation, and showed better tolerance to treatment with angiotensin-converting enzyme inhibitors/angiotensin receptor blockers and/or beta-blockers. RESULTS: In a primary analysis, the patients without hyperuricemia had the highest survival rate. After using the propensity score to set up comparable groups, the patients without hyperuricemia had a similar 5-year survival rate as those with untreated hyperuricemia (42.0% vs 39.7%, P = 0.362) whereas those with treated hyperuricemia had a poorer prognosis (32.4% survival rate, P = 0.006 vs non-hyperuricemia group and P = 0.073 vs untreated group). CONCLUSION: Hyperuricemia was associated with an unfavorable cardiovascular risk profile in HF patients. Treatment with low doses of allopurinol did not improve the prognosis of HF patients.

Macitentan in pulmonary hypertension due to left ventricular dysfunction.

The MELODY-1 study evaluated macitentan for pulmonary hypertension because of left heart disease (PH-LHD) in patients with combined post- and pre-capillary PH.63 patients with PH-LHD and diastolic pressure gradient ≥7 mmHg and pulmonary vascular resistance (PVR) >3WU were randomised to macitentan 10 mg (n=31) or placebo (n=32) for 12 weeks. The main end-point assessed a composite of significant fluid retention (weight gain ≥5% or ≥5 kg because of fluid overload or parenteral diuretic administration) or worsening in New York Heart Association functional class from baseline to end of treatment. Exploratory end-points included changes in N-terminal pro-brain natriuretic peptide (NT-proBNP) and haemodynamics at week 12.Seven macitentan-treated and four placebo-treated patients experienced significant fluid retention/worsening functional class; treatment difference, 10.08% (95% CI -15.07-33.26; p=0.34). The difference, driven by the fluid retention component, was apparent within the first month. At week 12, versus placebo, the macitentan group showed no change in PVR, mean right atrial pressure or pulmonary arterial wedge pressure; a non-significant increase in cardiac index (treatment effect 0.4 (95% CI 0.1-0.7) L·min-1·m-2) and decrease in NT-proBNP (0.77 (0.55-1.08)) was observed. Adverse events and serious adverse events were numerically more frequent with macitentan versus placebo.Macitentan-treated patients were quantitatively more likely to experience significant fluid retention versus placebo. Macitentan resulted in no significant changes in any exploratory end-points.

Bosentan added to sildenafil therapy in patients with pulmonary arterial hypertension.

The safety and efficacy of adding bosentan to sildenafil in pulmonary arterial hypertension (PAH) patients was investigated.In this prospective, double-blind, event-driven trial, symptomatic PAH patients receiving stable sildenafil (≥20 mg three times daily) for ≥3 months were randomised (1:1) to placebo or bosentan (125 mg twice daily). The composite primary end-point was the time to the first morbidity/mortality event, defined as all-cause death, hospitalisation for PAH worsening or intravenous prostanoid initiation, atrial septostomy, lung transplant, or PAH worsening. Secondary/exploratory end-points included change in 6-min walk distance and World Health Organization functional class at 16 weeks, change in N-terminal pro-brain natriuretic peptide (NT-proBNP) over time, and all-cause death.Overall, 334 PAH patients were randomised to placebo (n=175) or bosentan (n=159). A primary end-point event occurred in 51.4% of patients randomised to placebo and 42.8% to bosentan (hazard ratio 0.83, 97.31% CI 0.58-1.19; p=0.2508). The mean between-treatment difference in 6-min walk distance at 16 weeks was +21.8 m (95% CI +5.9-37.8 m; p=0.0106). Except for NT-proBNP, no difference was observed for any other end-point. The safety profile of bosentan added to sildenafil was consistent with the known bosentan safety profile.In COMPASS-2, adding bosentan to stable sildenafil therapy was not superior to sildenafil monotherapy in delaying the time to the first morbidity/mortality event.

Positive influence of being overweight/obese on long term survival in patients hospitalised due to acute heart failure.

BACKGROUND: Obesity is clearly associated with increased morbidity and mortality rates. However, in patients with acute heart failure (AHF), an increased BMI could represent a protective marker. Studies evaluating the "obesity paradox" on a large cohort with long-term follow-up are lacking. METHODS: Using the AHEAD database (a Czech multi-centre database of patients hospitalised due to AHF), 5057 patients were evaluated; patients with a BMI <18.5 kg/m2 were excluded. All-cause mortality was compared between groups with a BMI of 18.5-25 kg/m2 and with BMI >25 kg/m2. Data were adjusted by a propensity score for 11 parameters. RESULTS: In the balanced groups, the difference in 30-day mortality was not significant. The long-term mortality of patients with normal weight was higher than for those who were overweight/obese (HR, 1.36; 95% CI, 1.26-1.48; p<0.001)). In the balanced dataset, the pattern was similar (1.22; 1.09-1.39; p<0.001). A similar result was found in the balanced dataset of a subgroup of patients with de novo AHF (1.30; 1.11-1.52; p = 0.001), but only a trend in a balanced dataset of patients with acute decompensated heart failure. CONCLUSION: These data suggest significantly lower long-term mortality in overweight/obese patients with AHF. The results suggest that at present there is no evidence for weight reduction in overweight/obese patients with heart failure, and emphasize the importance of prevention of cardiac cachexia.

Epidemiology and long-term survival of pulmonary arterial hypertension in the Czech Republic: a retrospective analysis of a nationwide registry.

BACKGROUND: Pulmonary arterial hypertension (PAH) is a severe and progressive disease characterized by increased pulmonary vascular resistance, ultimately leading to right heart failure and death. Epidemiological data from national registries are growing worldwide, but are still unavailable in Eastern Europe. METHODS: A PAH registry was initiated in January 2007 using a nationwide network of echocardiographic centers and four diagnostic centers that specialize in PAH. All patients aged above 18 years, diagnosed with PAH and monitored between January 2000 and December 2007 were included. Patients diagnosed with PAH between January and December 2007 were classified as incident. The survival analyses were performed up to the end of 2010. Prognostic factors at the time of diagnosis were identified using uni- and multivariable Cox proportional hazard models. RESULTS: Overall, 191 patients were included (100 prevalent cases, 91 incident cases). Patients were predominantly female (n = 125) and had a mean age of 51.9 ± 16.9 years. Incident patients were significantly older at the time of diagnosis than prevalent patients (p < 0.001). Most patients (60.7%) had idiopathic PAH; 20.4% had PAH associated with congenital heart disease and 11.4% had PAH associated with connective tissue disease. Estimates of prevalence and incidence of PAH in adults were 22.4 cases per million and 10.7 cases per million per year, respectively. The 1-, 2- and 3-year survival rates in the incident PAH cohort were 89% (95% confidence intervals [CI] 83-95%), 78% (95% CI 70-87%) and 74% (95% CI 65-83%), respectively. Lower survival rates were significantly associated with higher age (hazard ratio [HR] 6.6 95% CI 1.4-30.9) and lower creatinine clearance (HR 3.3 95% CI 1.1-9.7). CONCLUSION: This is the first study in Eastern Europe to describe the prevalence, incidence and survival of patients with PAH from a national representative registry. This registry from the Czech Republic highlights that diagnosis of PAH is frequently made late in the disease continuum when patients have significant functional impairment.

Long-term results from the EARLY study of bosentan in WHO functional class II pulmonary arterial hypertension patients.

BACKGROUND: The double-blind phase of the EARLY study of bosentan remains the only randomized controlled trial of a PAH-targeted therapy in World Health Organization functional class (FC) II patients. We report on the efficacy, safety, disease worsening, survival and prognostic factors in mildly symptomatic pulmonary arterial hypertension (PAH) patients treated with bosentan in the open-label extension phase of the EARLY study. METHODS: Exploratory efficacy outcomes included 6-minute walk distance (6 MWD) and WHO FC. Adverse events were recorded. Kaplan-Meier analysis was used to estimate time to first PAH worsening event (death, initiation of intravenous or subcutaneous prostanoids, atrial septostomy or lung transplantation) and survival. Cox regression analysis determined factors prognostic of survival. RESULTS: Median exposure to bosentan (n=173) was 51 months. At the end of the bosentan-treatment assessment period, 77.8% of patients were in WHO FC I/II. Adverse events led to discontinuation of bosentan in 20.2% of patients. Aminotransferase elevations>3× upper limit of normal occurred in 16.8%. Four-year PAH-event-free survival and survival were 79.5% (95% confidence intervals [95% CI] 73.4, 85.6) and 84.8% [95% CI 79.4, 90.2], respectively. Low 6 MWD, low mixed venous oxygenation, high N-terminal pro hormone of brain natriuretic peptide levels and PAH associated with connective tissue disease were associated with a higher risk of death. CONCLUSIONS: The majority of patients exposed to long-term bosentan maintained or improved their functional class. Approximately 20% of the patients discontinued treatment because of adverse events, which were most commonly PAH worsening and elevated liver enzymes.

The effects of phosphodiesterase 5 inhibition on hemodynamics, functional status and survival in advanced heart failure and pulmonary hypertension: a case-control study.

BACKGROUND: The goal was to examine the hemodynamic and clinical effects of long-term therapy with PDE5 inhibitor sildenafil (SILD) in patients with advanced, pre-transplant heart failure (HF) and severe pulmonary hypertension (PH), in comparison to a similar control group (CON). METHODS: In this non-randomized, retrospective case-control study, 32 middle-aged patients (81% males) with advanced systolic HF (80%≥ NYHA III, 56% ischemic) and severe pre-capillary PH (transpulmonary pressure gradient>15 mm Hg) were studied before and after initiation of SILD (dose 73 ± 25 mg/day) and were compared to 15 CON patients, matched for key clinical characteristics (including PH severity, age and co-morbidities), not exposed to SILD. Changes at 3 months and the long-term outcome were compared between groups. RESULTS: SILD significantly reduced pulmonary vascular resistance (-32% vs. baseline), transpulmonary gradient (-25%) and increased cardiac output (+15%) compared to controls, without affecting systemic or ventricular filling pressures. SILD-treated subjects experienced an improvement in NYHA class and had a steady body weight which contrasted with significant weight loss in the CON group (by -4.8%, absolutely by 4.3 ± 6 kg). During follow-up (median 349 days from baseline), 60% of patients underwent heart transplantation. Two patients in CON group had severe post-transplant failure of the right ventricle, none in SILD group. Overall pre- and peritransplant survival (censored 30 days after transplantation) was significantly better in SILD than CON group (93.7 vs 60%, p=0.0048). CONCLUSIONS: In patients with advanced HF and severe PH, SILD therapy has beneficial effects on hemodynamics, clinical status, cardiac cachexia, and contributes to improved peri-transplant survival.

Transpulmonary B-type natriuretic peptide uptake and cyclic guanosine monophosphate release in heart failure and pulmonary hypertension: the effects of sildenafil.

OBJECTIVES: We sought to identify factors that discriminate heart failure (HF) patients with normal and elevated pulmonary vascular resistance (PVR) and to elucidate the role of cyclic guanosine monophosphate (cGMP)-dependent vasodilation. BACKGROUND: Mechanisms of PVR increase in patients with chronic HF are incompletely understood. METHODS: Twenty-two HF patients with high pulmonary vascular resistance (H-PVR) (>200 dyn.s.cm(-5)) were compared with 24 matched low pulmonary vascular resistance (L-PVR) patients of similar age, sex, body size, HF severity, and volume status who were undergoing invasive hemodynamic study. Pulmonary arterial (PA) and venous blood samples from a wedged PA catheter were used to calculate transpulmonary B-type natriuretic peptide (BNP) uptake and cGMP release. The H-PVR patients were re-examined 1 h after a 40-mg oral dose of sildenafil. RESULTS: Although transpulmonary BNP uptake was similar (p = 0.2), cGMP release was diminished in the H-PVR patients (-1.9 vs. 27.8 nmol.min(-1); p = 0.005). Transpulmonary BNP uptake and cGMP release correlated in the L-PVR patients (R = 0.6, p = 0.004) but not in the H-PVR. The H-PVR patients also had lower PA compliance, systemic arterial compliance (by 47% and 20%, p < 0.001 and p < 0.03), and cardiac index. Sildenafil reduced PVR (-47%), systemic resistance (-24%) and heart rate (-8%), increased cardiac index (+24%), and PA compliance (+87%, all p < 0.001), with a parallel increase of cGMP release (from -5.6 to 16.5 nmol.min(-1), p = 0.047), without affecting BNP uptake or norepinephrine(PA). The PVR response was not dependent on PA wedge pressure or pulmonary hypertension reversibility with prostaglandin E(1). CONCLUSIONS: The H-PVR patients have stiffening of both pulmonary and systemic arteries, preserved transpulmonary BNP uptake, but diminished cGMP release, which is reversible by the administration of sildenafil. This study provides in vivo evidence that phosphodiesterase 5A inhibition restores sensitivity of pulmonary vasculature to endogenous cGMP-dependent vasodilators.