Pulmonary arterial hypertension (PAH) is a heart failure syndrome characterized by right ventricular (RV) to pulmonary circulation uncoupling, counteracted by the sympathetic nervous system ...activation leading to β1-receptors and α-myosin heavy chain downregulation, downregulation of the sarcoplasmic reticulum Ca2+ATPase, and β-myosin heavy chain upregulation.
Increased ventilation (VE) associated with VE inefficiency further characterizes PAH, as shown by an elevated VE versus carbon dioxide relationship slope during exercise, reflecting a specific behavior with progressive increase of dead space (VD) VE. The sympathetic system interacts with chemoreceptor-mediated VE control with increased VD leading to VE/perfusion mismatch.
Growing evidence in the experimental models shows beneficial effects of different adrenoreceptor blockers on both right heart and pulmonary artery morphology and function. These effects can significantly change among β-blockers according to their different pharmacokinetic and pharmacodynamic profiles.
Since the first observation in the clinical setting, showing improvement associated with β-blocker withdraw in PAH patients, recent studies suggest that the effects of β-blockers in PAH might be related to the β1-adrenergic receptors selectivity and α1– and β3-related ancillary properties.
While in the advanced stages of PAH β-blockers may result deleterious as counteract the compensatory adrenergic-mediated effects of low cardiac output, in the early stages the modulation of the adrenergic system could ultimately improve VE efficiency and promote beneficial effects on heart failure gene expression and RV remodeling, particularly β1-selective blockers and those associated with α- or β3-activities.
At present, all the above are physiologically sound but clinically unproven suggestions, and need to be tested in future randomized controlled trials.
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Introduction
Phosphodiesterase 5 inhibitors (PDE5i) were developed while investigating novel treatments for coronary artery disease, but their andrological side effects shifted their indication ...toward the management of erectile dysfunction. Although PDE5i are now also indicated for pulmonary arterial hypertension and there are mounting preclinical and clinical evidences about their potentially beneficial cardiac effects, their use remains controversial and the involved mechanisms remain unclear.
Materials and methods
This review aimed to analyze the effects of PDE5i administration in various animal and humans models of cardiovascular diseases.
Results
Animal studies have shown that PDE5i have protective effects in several models of cardiac disease. In humans, some studies showed that PDE5i improves microvascular and endothelial dysfunction and exerts positive effects in different samples of cardiovascular (CV) impairment. In contrast, other studies found no benefit (and no harm) in heart failure with preserved ejection fraction. The discrepancies in these findings are likely related to the fact that the mechanisms targeted by PDE5i in human disease are still poorly understood and the target population not yet identified. The mechanisms of actions herein reviewed suggest that hypertrophy, microvascular impairment, and inflammation, should be variably present for PDE5i to work. All these conditions frequently coexist in diabetes. A gender responsiveness has also been recently proposed.
Conclusions
Continuous PDE5 inhibition may exert cardioprotective effects, improving endothelial function and counteracting cardiac remodeling in some but not all conditions. A better patient selection could help to clarify the controversies on PDE5i use for CV disorders.
Periodic repetition of right heart catheterization (RHC) in pulmonary arterial hypertension (PAH) can be challenging. We evaluated the correlation between RHC and cardiopulmonary exercise test (CPET) ...aiming at CPET use as a potential noninvasive tool for hemodynamic burden evaluation. One hundred and forty‐four retrospective PAH patients who had performed CPET and RHC within 2 months were enrolled. The following analyses were performed: (a) CPET parameters in hemodynamic variables tertiles; (b) position of hemodynamic parameters in the peak end‐tidal carbon dioxide pressure (PETCO2) versus ventilation/carbon dioxide output (VE/VCO2) slope scatterplot, which is a specific hallmark of exercise respiratory abnormalities in PAH; (c) association between CPET and a hemodynamic burden score developed including mean pulmonary arterial pressure (mPAP), pulmonary vascular resistance (PVR), cardiac index, and right atrial pressure. VE/VCO2 slope and peak PETCO2 significantly varied in mPAP and PVR tertiles, while peak oxygen uptake (peak VO2) and O2 pulse varied in the tertiles of all hemodynamic parameters. PETCO2 versus VE/VCO2 slope showed a strong hyperbolic relationship (R2 = 0.7627). Patients with peak PETCO2 > median (26 mmHg) and VE/VCO2 slope < median (44) presented lower mPAP and PVR (p < 0.005) than patients with peak PETCO2 < median and VE/VCO2 slope > median. Multivariate analysis individuated peak VO2 (p = 0.0158) and peak PETCO2 (p = 0.0089) as hemodynamic score independent predictors; the formula 11.584 − 0.0925 × peak VO2 − 0.0811 × peak PETCO2 best predicts the hemodynamic score value from CPET data. A significant correlation was found between estimated and calculated scores (p < 0.0001), with a precise match for patients with mild‐to‐moderate hemodynamic burden (76% of cases). The results of the present study suggest that CPET could allow to estimate the hemodynamic burden in PAH patients.
Pulmonary arterial hypertension (PAH) can be idiopathic or secondary to autoimmune diseases, and it represents one of the most threatening complications of systemic sclerosis (SSc). Macrophage ...migration inhibitory factor (MIF) is a pleiotropic cytokine with proinflammatory functions that appears to be involved in the pathogenesis of hypoxia-induced PH. In SSc patients, high serum levels of MIF have been associated with the development of ulcers and PAH. Stem cell growth factor β (SCGF β) is a human growth factor that, together with MIF, is involved in the pathogenesis of chronic spinal cord injury. The aim of our study was to measure serum levels of MIF in patients with idiopathic and SSc-associated PAH. We enrolled 13 patients with idiopathic PAH and 15 with SSc-associated PAH. We also selected 14 SSc patients without PAH and 12 normal healthy controls, matched for sex and age. PAH was confirmed by right hearth catheterism (mPAP>25 mmHg). MIF and SCGF β levels were measured by ELISA. We found significantly higher circulating levels of MIF and of SCGF β in patients with idiopathic PAH (P=0.03 and P=0.004) and with PAH secondary to SSc (P=0.018 and P=0.023) compared to SSc patients without PAH. Higher levels of MIF were found in those patients with an higher New York Heart Association (NYHA) class (P=0.03). We can hypothesize that MIF and SCGF β are able to play a role in PAH, both idiopathic or secondary, and in the future they may be evaluated as useful biomarkers and prognostic factors for this serious vascular disease.
Background: Oral bosentan is an established treatment for pulmonary arterial hypertension (PAH). Objective: To evaluate safety, tolerability, and clinical and haemodynamic effects of bosentan in ...patients with PAH related to congenital heart disease (CHD). Patients: 22 patients with CHD related PAH (8 men, 14 women, mean (SD) age 38 (10) years) were treated with oral bosentan (62.5 mg×2/day for the first 4 weeks and then 125 mg×2/day). Main outcome measures: Clinical status, liver enzymes, World Health Organisation (WHO) functional class, resting oxygen saturations and 6-min walk test (6MWT) were assessed at baseline and at 1, 3, 6, and 12 months. Haemodynamic evaluation with cardiac catheterisation was performed at baseline and at 12 month follow-up. Results: 12 patients had ventricular septal defect, 5 atrioventricular canal, 4 single ventricle, and 1 atrial septal defect. All patients tolerated bosentan well. No major side effects were seen. After a year of treatment, an improvement was seen in WHO functional class (2.5 (0.7) v 3.1 (0.7); p<0.05), oxygen saturation at rest (87 (6%) v 81 (9); p<0.001), heart rate at rest (81 (10) v 87 (14) bpm; p<0.05), distance travelled in the 6MWT (394 (73) v 320 (108) m; p<0.001), oxygen saturation at the end of the 6MWT (71 (14) v 63 (17%); p<0.05), Borg index (5.3 (1.8) v 6.5 (1.3); p<0.001), pulmonary vascular resistances index (14 (9) v 22 (12) WU m2; p<0.001), systemic vascular resistances index (23 (11) v 27 (10) WU.m2; p<0.01), pulmonary vascular resistances index/systemic vascular resistances index (0.6 (0.5) v 0.9 (0.6); p<0.05); pulmonary (4.0 (1.3) v 2.8 (0.9) l/min/m2; p<0.001) and systemic cardiac output (4.2 (1.4) v 3.4 (1.1) l/min/m2; p<0.05). Conclusions: Bosentan was safe and well tolerated in adults with CHD related PAH during 12 months of treatment. Clinical status, exercise tolerance, and pulmonary haemodynamics improved considerably.
Abstract
Background and Aim
Chronic thromboembolic pulmonary disease (CTED) is a progressive disease caused by a wall-adherent, fibrotic thrombus in the pulmonary circulation persisting despite oral ...anticoagulation and despite vascular remodeling of the small arteries. Despite normal pulmonary hemodynamics at rest, exercise intolerance and dyspnea have been reported. Drivers and risk factors, as well as the clinical impact of CTED, are not yet adequately characterized. We evaluated clinical factors predictive of the development of postthrombotic pulmonary disease in a cohort of patients with a history of acute pulmonary embolism on oral anticoagulant therapy. We also evaluated its impact on functional capacity, pulmonary haemodinamics at rest and after exercise and right ventricle morphology and function.
Methods
We compared 33 consecutive patients with a history of acute pulmonary embolism and normal pulmonary vascular imaging (group 1, n=16) or persistent defects on perfusion scan (positive P scan) despite therapeutic anticoagulation for 4 months (group 2, n=17), for the following parameters: 1. Thrombotic load (extension of pulmonary thromboembolism on CT angiography) and Pulmonary Embolism Severity Index (PESI) score at the time of admission to the Intensive Care Unit (ICU); 2. Presence of thrombophilia (factor V Leiden, prothrombin variant, lupus anticoagulant); 3. Cardiovascular risk factors; 4. Anthropometric and demographic parameters; 5. Anticoagulation treatment in ICU and at discharge. The two groups of patients were also compared for the World Health Organization functional class (WHO-FC), NT-proBNP, cardiopulmonary exercise test (CPET) and echocardiographic parameters at rest and after exercise (ESE), at 4 and after 24 months.
Results
Compared with group 1, patients with persisting perfusion defects (group 2) featured higher thrombotic load (p=0.004) and PESI score (p=0.02) at the time of ICU admission. At 4 months, group 2 developed exercise-induced pulmonary hypertension (Ex-PH) at CPET (p<0.001) and ESE (p<0.001). At the 24 months follow-up group 2 showed higher NT-proBNP (p<0.001) and WHO-FC (p<0.001), systolic (p<0.001) and diastolic (p=0.037) right ventricular (RV) dysfunction and worse echo indices of RV-Arterial Coupling (TAPSE/PAPs (p<0.001)), despite maintaining a low or intermediate echocardiographic probability of PH (Table 1).
Conclusions
Despite the low and intermediate echocardiographic probability of PH, patients with persistent positive P scan had reduced functional capacity, and developed ExPH and RV functional deterioration.
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