Sildenafil Improves Exercise Hemodynamics and Oxygen Uptake in Patients With Systolic Heart Failure

Considerations in the Diagnosis and Management of Pulmonary Hypertension Associated With Left Heart Disease

Pulmonary hypertension associated with left heart disease (PH-LHD) remains the most common cause of pulmonary hypertension globally. Etiologies include heart failure with reduced and preserved ejection fraction and left-sided valvular heart diseases. Despite the increasing prevalence of PH-LHD, there remains a paucity of knowledge about the hemodynamic definition, diagnosis, treatment modalities, and prognosis among clinicians. Moreover, clinical trials have produced mixed results on the usefulness of pulmonary vasodilator therapies for PH-LHD. In this expert review, we have outlined the critical role of meticulous hemodynamic evaluation and provocative testing for cases of diagnostic uncertainty. Therapeutic strategies-pharmacologic, device-based, and surgical therapies used for managing PH-LHD-are also outlined. PH-LHD in advanced heart failure, and the role of mechanical circulatory support in PH-LHD is briefly explored. An in-depth understanding of PH-LHD by all clinicians is needed for improved recognition and outcomes among patients with PH-LHD.

Endothelial Dysfunction in Heart Failure: What Is Its Role?

The endothelium is a continuous layer of cells that coats the interior walls of arteries, capillaries, and veins. It has an essential regulatory role in hemostatic function, vascular tone, inflammation, and platelet activity. Endothelial dysfunction is characterized by a shift to a proinflammatory and prothrombic state, and it could have a bidirectional relationship with heart failure (HF). Due to neurohormonal activation and shear stress, HFrEF may promote endothelial dysfunction, increase ROS synthesis, and reduce nitric oxide production. Different studies have also shown that endothelium function is damaged in HFpEF because of a systemic inflammatory state. Some clinical trials suggest that drugs that have an effect on endothelial dysfunction in patients with HF or cardiovascular disease may be a therapeutic option. The aim of this review is to highlight the pathogenetic correlation between endothelial dysfunction and heart failure and the related potential therapeutic options.

Phosphodiesterase in heart and vessels: from physiology to diseases

Phosphodiesterases (PDEs) are a superfamily of enzymes that hydrolyze cyclic nucleotides, including cyclic adenosine monophosphate (cAMP) and cyclic guanosine monophosphate (cGMP). Both cyclic nucleotides are critical secondary messengers in the neurohormonal regulation in the cardiovascular system. PDEs precisely control spatiotemporal subcellular distribution of cyclic nucleotides in a cell- and tissue-specific manner, playing critical roles in physiological responses to hormone stimulation in the heart and vessels. Dysregulation of PDEs has been linked to the development of several cardiovascular diseases, such as hypertension, aneurysm, atherosclerosis, arrhythmia, and heart failure. Targeting these enzymes has been proven effective in treating cardiovascular diseases and is an attractive and promising strategy for the development of new drugs. In this review, we discuss the current understanding of the complex regulation of PDE isoforms in cardiovascular function, highlighting the divergent and even opposing roles of PDE isoforms in different pathogenesis.

A roadmap for therapeutic discovery in pulmonary hypertension associated with left heart failure. A scientific statement of the Heart Failure Association (HFA) of the ESC and the ESC Working Group on Pulmonary Circulation & Right Ventricular Function

Pulmonary hypertension (PH) associated with left heart failure (LHF) (PH-LHF) is one of the most common causes of PH. It directly contributes to symptoms and reduced functional capacity and negatively affects right heart function, ultimately leading to a poor prognosis. There are no specific treatments for PH-LHF, despite the high number of drugs tested so far. This scientific document addresses the main knowledge gaps in PH-LHF with emphasis on pathophysiology and clinical trials. Key identified issues include better understanding of the role of pulmonary venous versus arteriolar remodelling, multidimensional phenotyping to recognize patient subgroups positioned to respond to different therapies, and conduct of rigorous pre-clinical studies combining small and large animal models. Advancements in these areas are expected to better inform the design of clinical trials and extend treatment options beyond those effective in pulmonary arterial hypertension. Enrichment strategies, endpoint assessments, and thorough haemodynamic studies, both at rest and during exercise, are proposed to play primary roles to optimize early-stage development of candidate therapies for PH-LHF.

The impact of phosphodiesterase-5 inhibition or angiotensin-converting enzyme inhibition on right and left ventricular remodeling in heart failure due to chronic volume overload

While phosphodiesterase-5 inhibition (PED5i) may prevent hypertrophy and failure in pressure-overloaded heart in an experimental model, the impact of PDE5i on volume-overload (VO)-induced hypertrophy is unknown. It is also unclear whether the hypertrophied right ventricle (RV) and left ventricle (LV) differ in their responsiveness to long-term PDE5i and if this therapy affects renal function. The goal of this study was to elucidate the effect of PDE5i treatment in VO due to aorto-caval fistula (ACF) and to compare PDE5i treatment with standard heart failure (HF) therapy with angiotensin-converting enzyme inhibitor (ACEi). ACF/sham procedure was performed on male HanSD rats aged 8 weeks. ACF animals were randomized for PDE5i sildenafil, ACEi trandolapril, or placebo treatments. After 20 weeks, RV and LV function (echocardiography, pressure-volume analysis), myocardial gene expression, and renal function were studied. Separate rat cohorts served for survival analysis. ACF led to biventricular eccentric hypertrophy (LV: +68%, RV: +145%), increased stroke work (LV: 3.6-fold, RV: 6.7-fold), and reduced load-independent systolic function (PRSW, LV: -54%, RV: -51%). Both ACF ventricles exhibited upregulation of the genes of myocardial stress and glucose metabolism. ACEi but not PDE5i attenuated pulmonary congestion, LV remodeling, albuminuria, and improved survival (median survival in ACF/ACEi was 41 weeks vs. 35 weeks in ACF/placebo, p = .02). PDE5i increased cyclic guanosine monophosphate levels in the lungs, but not in the RV, LV, or kidney. PDE5i did not improve survival rate and cardiac and renal function in ACF rats, in contrast to ACEi. VO-induced HF is not responsive to PDE5i therapy.

Is Pulmonary Capillary Wedge Pressure a Reliable Indicator of Postcapillary Pulmonary Hypertension?

Although current pulmonary hypertension (PH) guidelines recommend a pulmonary capillary wedge pressure (PCWP) >15 mm Hg for the detection of a postcapillary component, the rationale of this recommendation may not be quite compatible with the peculiar hemodynamics of PH. We hypothesize that a high PCWP alone does not necessarily indicate left-sided disease, and this diagnosis can be improved using left ventricle transmural pressure difference (∆ PTM). In this 2-center, retrospective, observational study, we enrolled 1,070 patients with PH who underwent heart catheterization, with the final study population comprising 961 cases. ∆ PTM was calculated as PCWP minus right atrial pressure. The patients with group II PH had significantly higher ∆ PTM values (12.6 ± 6.6 mm Hg) compared with the other groups (1.1 ± 4.8 in group I, 12.4 ± 6.6 in group II, 2.5 ± 6.4 in group III, and 0.8 ± 8.0 in group IV, p <0.001) despite overlapping PCWP values. A ∆ PTM cutoff of 7 mm Hg identifies left heart disease when PCWP is >15 (area under curve 0.825, 95% confidence interval 0.784 to 0.866, p <0.001). Five-year mortality was significantly higher in patients with high ∆ PTM and PCWP subgroups compared with low ∆ PTM plus high PCWP (26.1% vs 18.5%, p = 0.027) and low ∆ PTM and PCWP subgroups (26.1% vs 15.6%, p <0.001). ∆ PTM has supplementary discriminatory power in distinguishing patients with and without postcapillary PH. In conclusion, a new approach utilizing ∆ PTM may improve our understanding of PH pathophysiology and may identify a subpopulation that may potentially benefit from PH-specific treatments.

Pulmonary hypertension secondary to valvular heart disease: a state-of-the-art review

Pulmonary hypertension (PH) is a common disease affecting up to 1% of the population and at least 50% of patients diagnosed with heart failure (HF) (Hoeper et al. in Lancet Respir Med 4(4):306-322, 2016). It is estimated that PH is present in 15% to 60% of patients with valvular heart disease (VHD) which can result from an increase in pulmonary blood flow and subsequently in pulmonary venous congestion and pulmonary vascular resistance (PVR). It is important to identify the severity of PH in patients with VHD to appropriately risk stratify and manage these patients (Magne et al. in JACC Cardiovasc Imaging 8(1):83-99, 2015). In this review, we examine the diagnostic criteria for PH and its pathophysiology. We also focus on the growing evidence supporting the presence of PH secondary to VHD and describe the contemporary surgical and medical therapeutic interventions in this patient population (Fig. 1).

Advancements in Phosphodiesterase 5 Inhibitors: Unveiling Present and Future Perspectives

Phosphodiesterase 5 (PDE5) inhibitors presented themselves as important players in the nitric oxide/cGMP pathway, thus exerting a profound impact on various physiological and pathological processes. Beyond their well-known efficacy in treating male erectile dysfunction (ED) and pulmonary arterial hypertension (PAH), a plethora of studies have unveiled their significance in the treatment of a myriad of other diseases, including cognitive functions, heart failure, multiple drug resistance in cancer therapy, immune diseases, systemic sclerosis and others. This comprehensive review aims to provide an updated assessment of the crucial role played by PDE5 inhibitors (PDE5-Is) as disease-modifying agents taking their limiting side effects into consideration. From a medicinal chemistry and drug discovery perspective, the published PDE5-Is over the last 10 years and their binding characteristics are systemically discussed, and advancement in properties is exposed. A persistent challenge encountered with these agents lies in their limited isozyme selectivity; considering this obstacle, this review also highlights the breakthrough development of the recently reported PDE5 allosteric inhibitors, which exhibit an unparalleled level of selectivity that was rarely achievable by competitive inhibitors. The implications and potential impact of these novel allosteric inhibitors are meticulously explored. Additionally, the concept of multi-targeted ligands is critically evaluated in relation to PDE5-Is by inspecting the broader spectrum of their molecular interactions and effects. The objective of this review is to provide insight into the design of potent, selective PDE5-Is and an overview of their biological function, limitations, challenges, therapeutic potentials, undergoing clinical trials, future prospects and emerging uses, thus guiding upcoming endeavors in both academia and industry within this domain.

The effect of cardioplegic supplementation with sildenafil on cardiac energetics in a piglet model of cardiopulmonary bypass and cardioplegic arrest with warm or cold cardioplegia

Cardioplegic cardioprotection strategies used during paediatric open-heart surgery remain suboptimal. Sildenafil, a phosphodiesterase 5 (PDE-5) inhibitor, has been shown to be cardioprotective against ischemia/reperfusion injury in a variety of experimental models and this study therefore tested the efficacy of supplementation of cardioplegia with sildenafil in a piglet model of cardiopulmonary bypass and arrest, using both cold and warm cardioplegia protocols. Piglets were anaesthetized and placed on coronary pulmonary bypass (CPB), the aorta cross-clamped and the hearts arrested for 60 min with cardioplegia with or without sildenafil (10 nM). Twenty minutes after removal of cross clamp (reperfusion), attempts were made to wean the pigs from CPB. Termination was carried out after 60 min reperfusion. Throughout the protocol blood and left ventricular tissue samples were taken for analysis of selected metabolites (using HPLC) and troponin I. In both the cold and warm cardioplegia protocols there was evidence that sildenafil supplementation resulted in faster recovery of ATP levels, improved energy charge (a measure of metabolic flux) and altered release of hypoxanthine and inosine, two purine catabolites. There was no effect on troponin release within the studied short timeframe. In conclusion, sildenafil supplementation of cardioplegia resulted in improved cardiac energetics in a translational animal model of paediatric CPB surgery.

Cyclic nucleotide phosphodiesterases as therapeutic targets in cardiac hypertrophy and heart failure

Cyclic nucleotide phosphodiesterases (PDEs) modulate the neurohormonal regulation of cardiac function by degrading cAMP and cGMP. In cardiomyocytes, multiple PDE isozymes with different enzymatic properties and subcellular localization regulate local pools of cyclic nucleotides and specific functions. This organization is heavily perturbed during cardiac hypertrophy and heart failure (HF), which can contribute to disease progression. Clinically, PDE inhibition has been considered a promising approach to compensate for the catecholamine desensitization that accompanies HF. Although PDE3 inhibitors, such as milrinone or enoximone, have been used clinically to improve systolic function and alleviate the symptoms of acute HF, their chronic use has proved to be detrimental. Other PDEs, such as PDE1, PDE2, PDE4, PDE5, PDE9 and PDE10, have emerged as new potential targets to treat HF, each having a unique role in local cyclic nucleotide signalling pathways. In this Review, we describe cAMP and cGMP signalling in cardiomyocytes and present the various PDE families expressed in the heart as well as their modifications in pathological cardiac hypertrophy and HF. We also appraise the evidence from preclinical models as well as clinical data pointing to the use of inhibitors or activators of specific PDEs that could have therapeutic potential in HF.

A Comprehensive Review of Dilated Cardiomyopathy in Pre-clinical Animal Models in Addition to Herbal Treatment Options and Multi-modality Imaging Strategies

Dilated cardiomyopathy (DCM) is distinguished by ventricular chamber expansion, systolic dysfunction, and normal left ventricular (LV) wall thickness, and is mainly caused due to genetic or environmental factors; however, its aetiology is undetermined in the majority of patients. The focus of this work is on pathogenesis, small animal models, as well as the herbal medicinal approach, and the most recent advances in imaging modalities for patients with dilated cardiomyopathy. Several small animal models have been proposed over the last few years to mimic various pathomechanisms that contribute to dilated cardiomyopathy. Surgical procedures, gene mutations, and drug therapies are all characteristic features of these models. The pros and cons, including heart failure stimulation of extensively established small animal models for dilated cardiomyopathy, are illustrated, as these models tend to procure key insights and contribute to the development of innovative treatment techniques for patients. Traditional medicinal plants used as treatment in these models are also discussed, along with contemporary developments in herbal therapies. In the last few decades, accurate diagnosis, proper recognition of the underlying disease, specific risk stratification, and forecasting of clinical outcome, have indeed improved the health of DCM patients. Cardiac magnetic resonance (CMR) is the bullion criterion for assessing ventricular volume and ejection fraction in a reliable and consistent direction. Other technologies, like strain analysis and 3D echocardiography, have enhanced this technique's predictive and therapeutic potential. Nuclear imaging potentially helps doctors pinpoint the causative factors of left ventricular dysfunction, as with cardiac sarcoidosis and amyloidosis.

Endothelial dysfunction: developmental mechanisms and therapeutic strategies

Introduction: Every year the importance of the normal functioning of the endothelial layer of the vascular wall in maintaining the health of the body becomes more and more obvious.

The physiological role of the endothelium: The endothelium is a metabolically active organ actively involved in the regulation of hemostasis, modulation of inflammation, maintenance of hemovascular homeostasis, regulation of angiogenesis, vascular tone, and permeability.

Risk factors for the development of endothelial dysfunction: Currently, insufficient bioavailability of nitric oxide is considered the most significant risk factor for endothelial dysfunction.

Mechanisms of development of endothelial dysfunction: The genesis of endothelial dysfunction is a multifactorial process. Among various complex mechanisms, this review examines oxidative stress, inflammation, hyperglycemia, vitamin D deficiency, dyslipidemia, excess visceral fat, hyperhomocysteinemia, hyperuricemia, as well as primary genetic defect of endotheliocytes, as the most common causes in the population underlying the development of endothelial dysfunction.

Markers of endothelial dysfunction in various diseases: This article discusses the main biomarkers of endothelial dysfunction currently used, as well as promising biomarkers in the future for laboratory diagnosis of this pathology.

Therapeutic strategies: Therapeutic approaches to the endothelium in order to prevent or reduce a degree of damage to the vascular wall are briefly described.

Conclusion: Endothelial dysfunction is a typical pathological process involved in the pathogenesis of many diseases. Thus, pharmacological agents with endothelioprotective properties can provide more therapeutic benefits than a drug without such an effect.

Crosstalk between microRNA and Oxidative Stress in Heart Failure: A Systematic Review

Heart failure is defined as a clinical syndrome consisting of key symptoms and is due to a structural and/or functional alteration of the heart that results in increased intracardiac pressures and/or inadequate cardiac output at rest and/or during exercise. One of the key mechanisms determining myocardial dysfunction in heart failure is oxidative stress. MicroRNAs (miRNAs, miRs) are short, endogenous, conserved, single-stranded non-coding RNAs of around 21-25 nucleotides in length that act as regulators of multiple processes. A systematic review following the PRISMA guidelines was performed on the evidence on the interplay between microRNA and oxidative stress in heart failure. A search of Pubmed, Embase, Scopus, and Scopus direct databases using the following search terms: 'heart failure' AND 'oxidative stress' AND 'microRNA' or 'heart failure' AND 'oxidative stress' AND 'miRNA' was conducted and resulted in 464 articles. Out of them, 15 full text articles were eligible for inclusion in the qualitative analysis. Multiple microRNAs are involved in the processes associated with oxidative stress leading to heart failure development including mitochondrial integrity and function, antioxidant defense, iron overload, ferroptosis, and survival pathways.

Heart Failure with Preserved Ejection Fraction and Pulmonary Hypertension: Focus on Phosphodiesterase Inhibitors

Pulmonary hypertension (PH) is common in patients with heart failure with preserved ejection fraction (HFpEF). A chronic increase in mean left atrial pressure leads to passive remodeling in pulmonary veins and capillaries and modest PH (isolated postcapillary PH, Ipc-PH) and is not associated with significant right ventricular dysfunction. In approximately 20% of patients with HFpEF, "precapillary" alterations of pulmonary vasculature occur with the development of the combined pre- and post-capillary PH (Cpc-PH), pertaining to a poor prognosis. Current data indicate that pulmonary vasculopathy may be at least partially reversible and thus serves as a therapeutic target in HFpEF. Pulmonary vascular targeted therapies, including phosphodiesterase (PDE) inhibitors, may have a valuable role in the management of patients with PH-HFpEF. In studies of Cpc-PH and HFpEF, PDE type 5 inhibitors were effective in long-term follow-up, decreasing pulmonary artery pressure and improving RV contractility, whereas studies of Ipc-PH did not show any benefit. Randomized trials are essential to elucidate the actual value of PDE inhibition in selected patients with PH-HFpEF, especially in those with invasively confirmed Cpc-PH who are most likely to benefit from such treatment.

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.

Reactive Oxygen Species Induced Pathways in Heart Failure Pathogenesis and Potential Therapeutic Strategies

With respect to structural and functional cardiac disorders, heart failure (HF) is divided into HF with reduced ejection fraction (HFrEF) and HF with preserved ejection fraction (HFpEF). Oxidative stress contributes to the development of both HFrEF and HFpEF. Identification of a broad spectrum of reactive oxygen species (ROS)-induced pathways in preclinical models has provided new insights about the importance of ROS in HFrEF and HFpEF development. While current treatment strategies mostly concern neuroendocrine inhibition, recent data on ROS-induced metabolic pathways in cardiomyocytes may offer additional treatment strategies and targets for both of the HF forms. The purpose of this article is to summarize the results achieved in the fields of: (1) ROS importance in HFrEF and HFpEF pathophysiology, and (2) treatments for inhibiting ROS-induced pathways in HFrEF and HFpEF patients. ROS-producing pathways in cardiomyocytes, ROS-activated pathways in different HF forms, and treatment options to inhibit their action are also discussed.

Effects of phosphodiesterase 5 inhibition on cardiovascular function in resistant hypertension: A systematic review

Approximately 12-18% of hypertensive patients are diagnosed with resistant hypertension (RH). The risk of having worse cardiovascular outcomes is twice higher in those patients. The low effectiveness of conventional antihypertensive drugs in RH emphasizes the need to evaluate complementary drug therapies to achieve blood pressure (BP) control. Previous studies have demonstrated that phosphodiesterase 5 (PDE-5) inhibitors improve hemodynamics and reduce BP on essential hypertension. So, the authors aimed to summarize current clinical trials-based evidence published concerning the use of PDE-5 inhibitors on BP, cardiovascular function, and hemodynamics of patients with RH. We searched MEDLINE, EMBASE, LILACS, ClinicalTrials.gov, and WHO International Clinical Trials Registry databases on May 15th, 2020 using pre-defined search terms. Two independent reviewers assessed and extracted data from clinical trials that evaluated the effect of PDE-5 inhibitors on BP. We have included five articles in this systematic review. Four of them developed a single-day protocol, while one has developed a 14-day study. The main findings indicate that PDE-5 inhibitors ameliorate BP, vascular hemodynamics, and diastolic function parameters. Some data demonstrated improvement of endothelial function, but it was not a consensus. The side effects seemed to be limited and well-tolerated. In brief, our systematic review highlights the potential of PDE-5 inhibitors as a therapeutic alternative in addition to the multiple-drug regime for RH. Larger studies are still needed to determine whether the beneficial effects of PDE-5 inhibitors on RH would be maintained with chronic administration.

[Invasive Cardiopulmonary Exercise Testing: A Review]

Right heart catheterization (RHC) is the internationally standardized reference method for measuring pulmonary hemodynamics under resting conditions. In recent years, increasing efforts have been made to establish the reliable assessment of exercise hemodynamics as well, in order to obtain additional diagnostic and prognostic data. Furthermore, cardiopulmonary exercise testing (CPET), as the most comprehensive non-invasive exercise test, is increasingly performed in combination with RHC providing detailed pathophysiological insights into the exercise response, so-called invasive cardiopulmonary exercise testing (iCPET).In this review, the accumulated experience with iCPET is presented and methodological details are discussed. This complex examination is especially helpful in differentiating the underlying causes of unexplained dyspnea. In particular, early forms of cardiac or pulmonary vascular dysfunction can be detected by integrated analysis of hemodynamic as well as ventilatory and gas exchange data. It is expected that with increasing validation of iCPET parameters, a more reliable differentiation of normal from pathological stress reactions will be possible.

Pulmonary Hypertension in Left Heart Disease

Pulmonary hypertension is common in left heart disease and is related most commonly to passive back transmission of elevated left atrial pressures. Some patients, however, may develop pulmonary vascular remodeling superimposed on their left-sided heart disease. This review provides a contemporary appraisal of existing criteria to diagnose a precapillary component to pulmonary hypertension in left heart disease as well as discusses etiologies, management issues, and future directions.

Current Modulation of Guanylate Cyclase Pathway Activity-Mechanism and Clinical Implications

For years, guanylate cyclase seemed to be homogenic and tissue nonspecific enzyme; however, in the last few years, in light of preclinical and clinical trials, it became an interesting target for pharmacological intervention. There are several possible options leading to an increase in cyclic guanosine monophosphate concentrations. The first one is related to the uses of analogues of natriuretic peptides. The second is related to increasing levels of natriuretic peptides by the inhibition of degradation. The third leads to an increase in cyclic guanosine monophosphate concentration by the inhibition of its degradation by the inhibition of phosphodiesterase type 5. The last option involves increasing the concentration of cyclic guanosine monophosphate by the additional direct activation of soluble guanylate cyclase. Treatment based on the modulation of guanylate cyclase function is one of the most promising technologies in pharmacology. Pharmacological intervention is stable, effective and safe. Especially interesting is the role of stimulators and activators of soluble guanylate cyclase, which are able to increase the enzymatic activity to generate cyclic guanosine monophosphate independently of nitric oxide. Moreover, most of these agents are effective in chronic treatment in heart failure patients and pulmonary hypertension, and have potential to be a first line option.

Association of obesity-related inflammatory pathways with lung function and exercise capacity

BACKGROUND

Obesity has multifactorial effects on lung function and exercise capacity. The contributions of obesity-related inflammatory pathways to alterations in lung function remain unclear.

RESEARCH QUESTION

To examine the association of obesity-related inflammatory pathways with pulmonary function, exercise capacity, and pulmonary-specific contributors to exercise intolerance.

METHOD

We examined 695 patients who underwent cardiopulmonary exercise testing (CPET) with invasive hemodynamic monitoring at Massachusetts General Hospital between December 2006-June 2017. We investigated the association of adiponectin, leptin, resistin, IL-6, CRP, and insulin resistance (HOMA-IR) with pulmonary function and exercise parameters using multivariable linear regression.

RESULTS

Obesity-related inflammatory pathways were associated with worse lung function. Specifically, higher CRP, IL-6, and HOMA-IR were associated with lower percent predicted FEV₁ and FVC with a preserved FEV₁/FVC ratio suggesting a restrictive physiology pattern (P ≤ 0.001 for all). For example, a 1-SD higher natural-logged CRP level was associated with a nearly 5% lower percent predicted FEV₁ and FVC (beta -4.8, s.e. 0.9 for FEV1; beta -4.9, s.e. 0.8 for FVC; P < 0.0001 for both). Obesity-related inflammatory pathways were associated with worse pulmonary vascular distensibility (adiponectin, IL-6, and CRP, P < 0.05 for all), as well as lower pulmonary artery compliance (IL-6 and CRP, P ≤ 0.01 for both).

INTERPRETATION

Our findings highlight the importance of obesity-related inflammatory pathways including inflammation and insulin resistance on pulmonary spirometry and pulmonary vascular function. Specifically, systemic inflammation as ascertained by CRP, IL-6 and insulin resistance are associated with restrictive pulmonary physiology independent of BMI. In addition, inflammatory markers were associated with lower exercise capacity and pulmonary vascular dysfunction.

Elevated Pulmonary Pressure Noted on Echocardiogram: A Simplified Approach to Next Steps

An elevated right ventricular/pulmonary artery systolic pressure suggestive of pulmonary hypertension (PH) is a common finding noted on echocardiography and is considered a marker for poor clinical outcomes, regardless of the cause. Even mild elevation of pulmonary pressure can be considered a modifiable risk factor, informing the trajectory of patients' clinical outcome. Although guidelines have been published detailing diagnostic and management algorithms, this echocardiographic finding is often underappreciated or not acted upon. Hence, patients with PH are often diagnosed in clinical practice when hemodynamic abnormalities are already moderate or severe. This results in delayed initiation of potentially effective therapies, referral to PH centers, and greater patient morbidity and mortality. This mini-review presents a succinct, simplified case-based approach to the "next steps" in the work-up of PH, once elevated pulmonary pressures have been noted on an echocardiogram. Our goal is for clinicians to develop a good overview of diagnostic approach to PH and recognition of high-risk features that may require early referral.

The Relationship between Resistance Exercise Performance and Ventilatory Efficiency after Beetroot Juice Intake in Well-Trained Athletes

The assessment of ventilatory efficiency is critical to understanding the matching of ventilation (VE) and perfusion in the lungs during exercise. This study aimed to establish a causal physiological relationship between ventilatory efficiency and resistance exercise performance after beetroot juice (BJ) intake. Eleven well-trained males performed a resistance exercise test after drinking 140 mL of BJ (~12.8 mmol NO3-) or a placebo (PL). Ventilatory efficiency was assessed by the VE•VCO2-1 slope, the oxygen uptake efficiency slope and the partial pressure of end-tidal carbon dioxide (PetCO2). The two experimental conditions were controlled using a randomized, double-blind crossover design. The resistance exercise test involved repeating the same routine twice, which consisted of wall ball shots plus a full squat (FS) with a 3 min rest or without a rest between the two exercises. A higher weight lifted was detected in the FS exercise after BJ intake compared with the PL during the first routine (p = 0.004). BJ improved the VE•VCO2-1 slope and the PetCO2 during the FS exercise in the first routine and at rest (p < 0.05). BJ intake improved the VE•VCO2-1 slope and the PetCO2 coinciding with the resistance exercise performance. The ergogenic effect of BJ could be induced under aerobic conditions at rest.

Long-Term Clinical and Hemodynamic Outcomes after Heart Transplantation in Patients Pre-Treated with Sildenafil

BACKGROUND

Elevated pulmonary vascular resistance remains a major problem for heart transplant (HT) candidate selection.

OBJECTIVE

This study sought at assess the effect of pre-HT sildenafil administration in patients with fixed pulmonary hypertension.

METHODS

This retrospective, single-center study included 300 consecutive, HT candidates treated between 2003 and 2013, in which 95 patients had fixed PH, and of these, 30 patients were treated with sildenafil and eventually received a transplant, forming Group A. Group B included 205 patients without PH who underwent HT. Pulmonary hemodynamics were evaluated before HT, as well as 1 week after and 1 year after HT. Survival was compared between the groups. In this study, a p value < 0.05 was considered statistically significant.

RESULTS

After treatment with sildenafil but before HT, PVR (-39%) and sPAP (-10%) decreased significantly. sPAP decreased after HT in both groups, but it remained significantly higher in group A vs. group B (40.3 ± 8.0 mmHg vs 36.5 ± 11.5 mmHg, p=0.022). One year after HT, sPAP was 32.4 ± 6.3 mmHg in group A vs 30.5 ± 8.2 mmHg in group B (p=0.274). The survival rate after HT at 30 days (97% in group A versus 96% in group B), at 6 months (87% versus 93%) and at one year (80% vs 91%) were not statistically significant (Log-rank p=0.063). After this first year, the attrition rate was similar among both groups (conditional survival after 1 year, Log-rank p=0.321).

CONCLUSION

In patients with severe PH pre-treated with sildenafil, early post-operative hemodynamics and prognosis are numerically worse than in patients without PH, but after 1 year, the medium to long-term mortality proved to be similar. (Arq Bras Cardiol. 2021; 116(2):219-226).

PDE5 Inhibitors in Type 2 Diabetes Cardiovascular Complications

Pharmacological inhibition of Phosphodiesterase type 5 (PDE5) proved its efficacy treating several pathological conditions, such as erectile dysfunction and pulmonary hypertension. Nowadays, its benefits on cardiovascular diseases are well documented, particularly in the treatment of type 2 diabetes (T2DM)-related cardiovascular complications. In this context, treatment of T2DM with PDE5 inhibitors, such as sildenafil, tadalafil or vardenafil ameliorates endothelial dysfunction both in patients and animal models through an augmented flow mediated dilation rate and an up-regulation of endothelial markers; it also reduces the inflammatory state by down-regulating inflammatory cytokines expression and improves diabetic cardiomyopathy and ischemia-reperfusion injury mainly through the activation of NO-cGMP-PKG pathway. The present review summarizes the state of art on PDE5 inhibition in the treatment of cardiovascular complications in T2DM.

Pulmonary vascular resistance as a potential marker of reactive pulmonary hypertension reduction following sildenafil therapy in patients disqualified from orthotopic heart transplantation

PURPOSE

We sought to determine the predictors of restoration of heart transplantation (HTx) candidacy in patients with systolic heart failure (HF) and reactive fixed pulmonary hypertension (RFPH) defined as pulmonary vascular resistance (PVR) > 2.5 Wood units (WU), transpulmonary gradient (TPG) > 12 mmHg or ≤2.5 WU with systolic arterial pressure ≤85 mmHg during vasoreactivity test, following sildenafil therapy.

MATERIAL AND METHODS

Between 2007 and 2018 1136 patients were evaluated at our department as candidates for HTx. Thirty-five of them, who presented with systolic HF and were not eligible for HTx due to RFPH, were included in the study (31 men aged 55.1 ± 7.4 years). In all the patients sildenafil was introduced and up-titrated to a maximal tolerated dose in addition to optimal medical therapy. Patients were assessed at 3-6 months intervals.

RESULTS

During median 11 months (interquartile range 6-18 months) reduction of RFPH enabling qualification for HTx was observed in 62.9% patients. Higher baseline PVR (OR 0.32; 95% CI (0.14-0.74) p < 0.001), pulmonary artery systolic pressure (PASP) (OR 0.94, 95% CI (0.88-0.99) p = 0.05), mean artery pulmonary pressure (mPAP) (OR 0.87, 95% CI (0.77-0.98) p = 0.02) and TPG (OR 082, 95% CI (0.70-0.96) p = 0.003) were negative predictors of RFPH reduction with sildenafil therapy. In multivariable analysis, lower PVR (p = 0.02) was identified as an independent predictor of RFPH reduction following sildenafil therapy.

CONCLUSION

Sildenafil therapy can support PH reduction in systolic HF patients uneligible for HTx due to RFPH. Lower baseline PVR was identified as an independent predictor of PH reversibility with sildenafil enabling restoration of HTx candidacy.

PERK-Mediated Suppression of microRNAs by Sildenafil Improves Mitochondrial Dysfunction in Heart Failure

Oxidative/nitrosative stress is a major trigger of cardiac dysfunction, involving the unfolded protein response and mitochondrial dysfunction. Activation of nitric oxide-cyclic guanosine monophosphate-protein kinase G signaling by sildenafil improves cardiac mal-remodeling during pressure-overload-induced heart failure. Transcriptome analysis was conducted in failing hearts with or without sildenafil treatment. Protein kinase R-like endoplasmic reticulum (ER) kinase (PERK) downstream signaling pathways, EIF2 and NRF2, were significantly altered. Although EIF2 signaling was suppressed, NRF2 signaling was upregulated, inhibiting the maturation of miR 24-3p through EGFR-mediated Ago2 phosphorylation. To study the effect of sildenafil on these pathways, we generated cardiac-specific PERK knockout mice. In these mice, sildenafil could not inhibit the maturations, the nuclear translocation of NRF2 was suppressed, and mitochondrial dysfunction advanced. Altogether, these results show that PERK-mediated suppression of miRNAs by sildenafil is vital for maintaining mitochondrial homeostasis through NRF2-mediated oxidative stress response.

Targeting the NO-cGMP-PDE5 pathway in COVID-19 infection. The DEDALO project

Background

A pandemic outbreak of COVID‐19 has been sweeping the world since December. It begins as a respiratory infection that, mainly in men with diabetes or renal impairment, evolves into a systemic disease, with SARDS, progressive endothelial cell damage, abnormal clotting and impaired cardiovascular and liver function. Some clinical trials are testing biological drugs to limit the immune system dysregulation, “cytokines storm,” that causes the systemic complications of COVID‐19. The contraindications of these drugs and their cost raise concerns over the implications of their widespread availability.

Objectives

Numerous clinical and experimental studies have revealed a role for the nitric oxide (NO)‐cyclic GMP‐phosphodiesterase type 5 (PDE5) pathway in modulating low‐grade inflammation in patients with metabolic diseases, offering cardiovascular protection. PDE5 inhibition favors an anti‐inflammatory response by modulating activated T cells, reducing cytokine release, lowering fibrosis, increasing oxygen diffusion, stimulating vascular repair. PDE5 is highly expressed in the lungs, where its inhibition improves pulmonary fibrosis, a complication of severe COVID‐19 disease.

Materials and methods

We performed a systematic review of all evidence documenting any involvement of the NO‐cGMP‐PDE5 axis in the pathophysiology of COVID‐19, presenting the ongoing clinical trials aimed at modulating this axis, including our own “silDEnafil administration in DiAbetic and dysmetaboLic patients with COVID‐19 (DEDALO trial).”

Results

The reviewed evidence suggests that PDE5 inhibitors could offer a new strategy in managing COVID‐19 by (i) counteracting the Ang‐II‐mediated downregulation of AT‐1 receptor; (ii) acting on monocyte switching, thus reducing pro‐inflammatory cytokines, interstitial infiltration and the vessel damage responsible for alveolar hemorrhage‐necrosis; (iii) inhibiting the transition of endothelial and smooth muscle cells to mesenchymal cells in the pulmonary artery, preventing clotting and thrombotic complications.

Discussion and Conclusion

If the ongoing trials presented herein should provide positive findings, the low cost, wide availability and temperature stability of PDE5 inhibitors could make them a major resource to combat COVID‐19 in developing countries.

Off-label use of pulmonary vasodilators after left ventricular assist device implantation: Calling in the evidence

Left ventricular assist devices (LVAD) are increasingly implanted in advanced heart failure patients to improve survival and quality of life either as a bridge to transplant, bridge to recovery or as destination therapy. LVAD therapy is often accompanied by a profound lowering of pulmonary artery pressure due to mechanical unloading of the left ventricle. Persistent pulmonary hypertension (PH) after LVAD implantation increases the risk of right ventricular failure (RVF). In this context pulmonary vasodilators have been implemented: a) as a strategy to reduce afterload and wean patients with RVF from inotropes in the early postoperative period, b) as long-term therapy aiming to optimize right heart hemodynamics and prevent late RVF and c) in order to lower persistently elevated pulmonary artery pressure (PAP) and pulmonary vascular resistance (PVR) after LVAD and enable candidacy for heart transplantation. However, considerable uncertainty exists regarding the risks and benefits of these strategies and practices vary widely among institutions. This article provides an overview of the available evidence and existing recommendations regarding the use of pulmonary vasodilators in LVAD recipients.

The left atrium and the right ventricle: two supporting chambers to the failing left ventricle

Heart failure (HF) is mainly caused by left ventricular (LV) impairment of function, hence detailed assessment of its structure and function is a clinical priority. The frequent involvement of the left atrium (LA) and the right ventricle (RV) in the overall cardiac performance has recently gained significant interest with specific markers predicting exercise intolerance and prognosis being proposed. The LA and RV are not anatomically separated from the LV, while the LA controls the inlet the RV shares the interventricular septum with the LV. Likewise, the function of the two chambers is not entirely independent from that of the LV, with the LA enlarging to accommodate any rise in filling pressures, which could get transferred to the RV via the pulmonary circulation. In the absence of pulmonary disease, LA and RV function may become impaired in patients with moderate-severe LV disease and raised filling pressures. These changes can often occur irrespective of the severity of systolic dysfunction, thus highlighting the important need for critical assessment of the function of the two chambers. This review evaluates the pivotal role of the left atrium and right ventricle in the management of HF patients based on the available evidence.

Clinical and Hemodynamic Associations and Prognostic Implications of Ventilatory Efficiency in Patients With Preserved Left Ventricular Systolic Function

BACKGROUND

Ventilatory efficiency (minute ventilation required to eliminate carbon dioxide, VE/VCO2) during exercise potently predicts outcomes in advanced heart failure with reduced ejection fraction, but its prognostic significance for at-risk individuals with preserved left ventricular systolic function is unclear. We aimed to characterize mechanistic determinants and prognostic implications of VE/VCO2 in a single-center dyspneic referral cohort (MGH-ExS [Massachusetts General Hospital Exercise Study]) and in a large sample of community-dwelling participants in the FHS (Framingham Heart Study).

METHODS

Maximum incremental cardiopulmonary exercise tests were performed. VE/VCO2 was assessed as the slope pre- and post-ventilatory anaerobic threshold (VE/VCO2_pre-VATslope, VE/VCO2_{post-VATslope}), the slope throughout exercise (VE/VCO2_{overall-slope}), and as the lowest 30-second value (VE/VCO2_nadir).

RESULTS

In the MGH-ExS (N=493, age 56±15 years, 61% women, left ventricular ejection fraction 64±8%), higher VE/VCO2_nadir was associated with lower peak exercise cardiac output and steeper increases in exercise pulmonary capillary wedge pressure (both P<0.0001). VE/VCO2_nadir (hazard ratio, 1.34 per 1-SD unit [95% CI, 1.10-1.62] P=0.003) was associated with future cardiovascular hospitalization/death and outperformed classical VE/VCO2 measures used in heart failure with reduced ejection fraction (VE/VCO2_{overall-slope}). In FHS (N=1936, age 54±9 years, 53% women), VE/VCO2 measures taken in low-to-moderate intensity exercise (including VE/VCO2_pre-VATslope, VE/VCO2_nadir) were directly associated with cardiovascular risk factor burden (smoking, Framingham cardiovascular disease risk score, and lower fitness; all P<0.001).

CONCLUSIONS

Impaired ventilatory efficiency is associated with cardiovascular risk in the community and with adverse hemodynamic profiles and future hospitalizations/death in a referral population, highlighting the prognostic importance of easily acquired submaximum exercise ventilatory gas exchange measurements in broad populations with preserved left ventricular systolic function.

Right Ventricular Function in Chronic Heart Failure: From the Diagnosis to the Therapeutic Approach

There is growing attention for the study of the right ventricle in cardiovascular disease and in particular in heart failure. In this clinical setting, right ventricle dysfunction is a significant marker of poor prognosis, regardless of the degree of left ventricular dysfunction. Novel echocardiographic methods allow for obtaining a more complete evaluation of the right ventricle anatomy and function as well as of the related abnormalities in filling pressures. Specific and effective therapies for the right ventricle dysfunction are still not well defined and this represents the most difficult and important challenge. This article focuses on available diagnostic techniques for studying right ventricle dysfunction as well as on the therapies for right ventricle dysfunction.

Pulmonary Hypertension in Heart Failure Patients

The development of pulmonary hypertension (PH) in patients with heart failure is associated with increased morbidity and mortality. In this article, the authors examine recent changes to the definition of PH in the setting of left heart disease (PH-LHD), and discuss its epidemiology, pathophysiology and prognosis. They also explore the complexities of diagnosing PH-LHD and the current evidence for the use of medical therapies, promising clinical trials and the role of left ventricular assist device and transplantation.

Sedentary Behavior, Exercise, and Cardiovascular Health

Sedentary behavior and physical inactivity are among the leading modifiable risk factors worldwide for cardiovascular disease and all-cause mortality. The promotion of physical activity and exercise training (ET) leading to improved levels of cardiorespiratory fitness is needed in all age groups, race, and ethnicities and both sexes to prevent many chronic diseases, especially cardiovascular disease. In this state-of-the-art review, we discuss the negative impact of sedentary behavior and physical inactivity, as well as the beneficial effects of physical activity /ET and cardiorespiratory fitness for the prevention of chronic noncommunicable diseases, including cardiovascular disease. We review the prognostic utility of cardiorespiratory fitness compared with obesity and the metabolic syndrome, as well as the increase of physical activity /ET for patients with heart failure as a therapeutic strategy, and ET dosing. Greater efforts at preventing sedentary behavior and physical inactivity while promoting physical activity, ET, and cardiorespiratory fitness are needed throughout the healthcare system worldwide and particularly in the United States in which the burden of cardiometabolic diseases remains extremely high.

Associations Between the Cyclic Guanosine Monophosphate Pathway and Cardiovascular Risk Factors: MESA

Background

cGMP mediates numerous cardioprotective functions and is a potential therapeutic target for cardiovascular disease. Preclinical studies suggest that plasma cGMP is reflective of natriuretic peptide stimulation. Epidemiologic associations between cGMP and natriuretic peptide, as well as cardiovascular disease risk factors, are unknown.

Methods and Results

We measured plasma cGMP in 542 men and 496 women free of cardiovascular disease and heart failure in MESA (Multi‐Ethnic Study of Atherosclerosis). Cross‐sectional associations of N‐terminal pro‐B type natriuretic peptide, sex hormones, and cardiovascular disease/heart failure risk factors with log(cGMP) were analyzed using multivariable linear regression models. Mean (SD) cGMP was 4.7 (2.6) pmol/mL, with no difference between the sexes. After adjusting for cardiovascular risk factors, N‐terminal pro‐B type natriuretic peptide was significantly positively associated with cGMP (P<0.05). Higher blood pressure and lower estimated glomerular filtration rate were associated with higher cGMP (P<0.05). Triglyceride levels, total/high‐density lipoprotein cholesterol ratio, presence of diabetes mellitus, and the homeostatic model assessment of insulin resistance were inversely associated with cGMP (P<0.05). Among women, free testosterone and dehydroepiandrosterone were inversely associated with cGMP, while sex hormone binding globulin was positively associated (P<0.05).

Conclusions

In a community‐cohort, plasma cGMP was associated with natriuretic peptide signaling. Higher blood pressure and greater renal dysfunction were positively associated with cGMP, while adverse metabolic risk factors were inversely associated. Increased androgenicity in postmenopausal women was inversely associated with cGMP. These novel associations further our understanding of the role of cGMP in a general population.

Left Ventricular Assist Device Support Complicates the Exercise Physiology of Oxygen Transport and Uptake in Heart Failure

Low-output forward flow and impaired maximal exercise oxygen uptake (VO₂ max) are hallmarks of patients in advanced heart failure. The continuous-flow left ventricular assist device is a cutting-edge therapy proven to increase forward flow, yet this therapy does not yield consistent improvements in VO₂ max. The science of how adjustable artificial forward flow impacts the exercise physiology of heart failure and physical O₂ transport between the central and peripheral systems is unclear. This review focuses on the exercise physiology of axial continuous-flow left ventricular assist device support and the impact that pump speed has on the interactive convective and diffusive components of whole-body physical O₂ transport and VO₂.

Pre-Operative Sildenafil for Patients With Pulmonary Hypertension Undergoing Mitral Valve Surgery: A Systematic Review and Meta-Analysis

Background

Pulmonary hypertension is a usual complication of long-standing mitral valve disease. Perioperative pulmonary hypertension is a risk factor for right ventricular failure and is an important cause of morbidity and mortality in patients with pulmonary hypertension undergoing mitral valve surgery. Phosphodiesterase-5 inhibitors particularly sildenafil citrate have proven clinical benefit for pulmonary arterial hypertension but have shown discordant results in group 2 pulmonary hypertension patients. We sought to determine the effect of pre-operative sildenafil on the intra-operative hemodynamic parameters of these patients.

Methods

Studies were included if they satisfied the following criteria: 1) Randomized controlled trials; 2) Adult patients with pulmonary hypertension scheduled for elective mitral valve surgery; and 3) Reported data on changes in pre-, intra-, and post-operative hemodynamic parameters. Using PUBMED, Clinical Key, Science Direct, and Cochrane databases, a search for eligible studies was conducted from September 1 to December 31, 2018. The quality of each study was evaluated using the Cochrane Risk of Bias Tool. The primary outcome of interest is on the effect of pre-operative sildenafil on the improvement of intra-operative hemodynamic parameters such as systolic pulmonary artery pressure (sPAP), mean pulmonary arterial pressure, mean arterial pressure, pulmonary and systemic vascular resistances. We also investigated its effect on the post-operative mortality, length of cardiopulmonary bypass time, ventilation time, and inotrope support requirement. Review Manager 5.3 was utilized to perform analysis of random effects for continuous outcomes.

Results

We identified three studies involving 153 patients with pulmonary hypertension undergoing mitral valve surgery, showing that among those who received pre-operative sildenafil there is a significant decrease in intra-operative systolic pulmonary arterial pressure (mean difference -11.19 (95% confidence interval (CI), -20.23 to -2.15), P < 0.05) and post-operative sPAP (mean difference -13.67 (95% CI, - 19.56 to - 7.78), P < 0.05) without significantly affecting the mean arterial pressure (mean difference 1.94 (95% CI, -5.49 to 9.37), P < 0.05). The systemic and pulmonary vascular resistances were not affected as well.

Conclusions

Administration of pre-operative sildenafil to patients with pulmonary hypertension undergoing mitral valve surgery decreases intra-operative and post-operative systolic pulmonary arterial pressure without significantly affecting other systemic hemodynamic parameters.

Sildenafil for improving outcomes in patients with corrected valvular heart disease and persistent pulmonary hypertension: a multicenter, double-blind, randomized clinical trial

Aims

We aimed to determine whether treatment with sildenafil improves outcomes of patients with persistent pulmonary hypertension (PH) after correction of valvular heart disease (VHD).

Methods and results

The sildenafil for improving outcomes after valvular correction (SIOVAC) study was a multricentric, randomized, parallel, and placebo-controlled trial that enrolled stable adults with mean pulmonary artery pressure ≥ 30 mmHg who had undergone a successful valve replacement or repair procedure at least 1 year before inclusion. We assigned 200 patients to receive sildenafil (40 mg three times daily, n = 104) or placebo (n = 96) for 6 months. The primary endpoint was the composite clinical score combining death, hospital admission for heart failure (HF), change in functional class, and patient global self-assessment. Only 27 patients receiving sildenafil improved their composite clinical score, as compared with 44 patients receiving placebo; in contrast 33 patients in the sildenafil group worsened their composite score, as compared with 14 in the placebo group [odds ratio 0.39; 95% confidence interval (CI) 0.22–0.67; P < 0.001]. The Kaplan–Meier estimates for survival without admission due to HF were 0.76 and 0.86 in the sildenafil and placebo groups, respectively (hazard ratio 2.0, 95% CI = 1.0–4.0; log-rank P = 0.044). Changes in 6-min walk test distance, natriuretic peptides, and Doppler-derived systolic pulmonary pressure were similar in both groups.

Conclusion

Treatment with sildenafil in patients with persistent PH after successfully corrected VHD is associated to worse clinical outcomes than placebo. Off-label usage of sildenafil for treating this source of left heart disease PH should be avoided.

The trial is registered with ClinicalTrials.gov, number NCT00862043.

[Mechanisms of exercise intolerance in patients with heart failure and preserved ejection fraction. Part II: The role of right heart chambers, vascular system and skeletal muscles]

The main clinical manifestation of heart failure with preserved ejection fraction is poor exercise tolerance. In addi-tion to the dysfunction of the left heart chambers, which were presented in the first part of this review, many other disorders are involved in poor exercise tolerance in such patients: impairments of the right heart, vascular system and skeletal muscle. The second part of this review presents the mechanisms for the development of these disorders, as well as possible ways to correct them.

Sildenafil enhances central hemodynamic responses to exercise, but not V̇o2peak, in people with diabetes mellitus

Exercise capacity is frequently reduced in people with diabetes mellitus (DM), and the contribution of pulmonary microvascular dysfunction remains undefined. We hypothesized that pulmonary microvascular disease, measured by a novel exercise echocardiography technique termed pulmonary transit of agitated contrast (PTAC), would be greater in subjects with DM and that the use of pulmonary vasodilator agent sildenafil would improve exercise performance by reducing right ventricular afterload. Forty subjects with DM and 20 matched controls performed cardiopulmonary exercise testing and semisupine exercise echocardiography 1 h after placebo or sildenafil ingestion in a double-blind randomized crossover design. The primary efficacy end point was exercise capacity (V̇o2peak) while secondary measures included pulmonary vascular resistance, cardiac output, and change in PTAC. DM subjects were aged 44 ± 13 yr, 73% male, with 16 ± 10 yr DM history. Sildenafil caused marginal improvements in echocardiographic measures of biventricular systolic function in DM subjects. Exercise-induced increases in pulmonary artery systolic pressure and pulmonary vascular resistance were attenuated with sildenafil, while heart rate (+2.4 ±1.2 beats/min, P = 0.04) and cardiac output (+322 ± 21 ml, P = 0.03) improved. However, the degree of PTAC did not change (P = 0.93) and V̇o2peak did not increase following sildenafil as compared with placebo (V̇o2peak: 31.8 ± 9.7 vs. 32.1 ± 9.5 ml·min-1·kg-1, P = 0.42). We conclude that sildenafil administration causes modest acute improvements in central hemodynamics but does not improve exercise capacity. This may be due to the mismatch in action of sildenafil on the pulmonary arteries rather than the distal pulmonary microvasculature and potential adverse effects on peripheral oxygen extraction. NEW & NOTEWORTHY This is one of the largest and most comprehensive studies of cardiopulmonary exercise performance in people with diabetes mellitus and to our knowledge the first to assess the effect of sildenafil using detailed echocardiographic measures during incremental exercise. Sildenafil attenuated the rise in pulmonary vascular resistance while augmenting cardiac output and intriguingly heart rate, without conferring any improvement in exercise capacity. The enhanced central hemodynamic indexes may have been offset by reduced peripheral O2 extraction.

Novel approaches to the management of chronic systolic heart failure: future directions and unanswered questions

Despite improvements in outcomes in the last few decades for heart failure (HF) with reduced ejection fraction (HFrEF), there still remains a need for novel therapies as many patients incompletely recover with existing therapies and progress to advanced HF. In this review, we will discuss recent advances in the management of HFrEF with a focus on upcoming therapies that hold the greatest promise for clinical use. We will discuss novel pharmacological therapies and areas of uncertainty with existing therapies. We will also discuss the potential utility and controversy surrounding novel interventions for HF such as percutaneous mitral valve repair, atrial fibrillation ablation, and other emerging interventions with positive signals for benefit in HFrEF. Finally, we will summarize the current state of stem cell and gene therapy for HFrEF and future directions.

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Preimplant Phosphodiesterase-5 Inhibitor Use Is Associated With Higher Rates of Severe Early Right Heart Failure After Left Ventricular Assist Device Implantation

Background Early right heart failure (RHF) occurs commonly in left ventricular assist device (LVAD) recipients, and increased right ventricular (RV) afterload may contribute. Selective pulmonary vasodilators, like phosphodiesterase-5 inhibitors (PDE5i), are used off-label to reduce RV afterload before LVAD implantation, but the association between preoperative PDE5i use and early RHF after LVAD is unknown. Methods and Results We analyzed adult patients from the INTERMACS registry (Interagency Registry for Mechanically Assisted Circulatory Support) who received a continuous flow LVAD after 2012. Patients on PDE5i were propensity-matched 1:1 to controls. The primary outcome was the incidence of severe early RHF, defined as the composite of death from RHF within 30 days, need for RV assist device support within 30 days, or use of inotropes beyond 14 days. Of 11 544 continuous flow LVAD recipients, 1199 (10.4%) received preoperative PDE5i. Compared to controls, patients on PDE5i had higher pulmonary artery systolic pressure (53.4 mm Hg versus 49.5 mm Hg) and pulmonary vascular resistance (2.6 WU versus 2.3 WU; P<0.001 for both). Before propensity matching, the incidence of severe early RHF was higher among patients on PDE5i than in controls (29.4% versus 23.1%; unadjusted odds ratio (OR), 1.32; 95% CI, 1.17-1.50). This association persisted after propensity matching (PDE5i, 28.9% versus control 23.7%; OR, 1.31; 95% CI, 1.09-1.57), driven by a higher incidence of prolonged inotropic support. Similar results were observed across a wide range of subgroups stratified by markers of pulmonary vascular disease and RV dysfunction. Conclusions Patients treated with preoperative PDE5i had markers of increased RV afterload and HF severity compared to unmatched controls. Even after propensity matching, patients receiving preimplant PDE5i therapy had higher rates of post-LVAD RHF.

Challenges in pulmonary hypertension associated with left heart disease

Introduction: Pulmonary hypertension (PH) secondary to left-sided heart disease (Group 2 PH) is a frequent complication of heart failure (HF) and is a heterogeneous phenotypic disorder that worsens exercise capacity, increases risk for hospitalization and survival independent of left ventricular ejection fraction (LVEF) or stage of HF. Areas covered: In this review, an update of the current knowledge and some potential challenges about the pathophysiology and treatments of group 2 PH in patients with HF of either preserved or reduced ejection fraction are provided. Also, this review discusses the epidemiology and provides hints for the optimal evaluation and diagnosis of these patients to prevent misclassification of their pulmonary hypertension. Expert opinion: There are many of areas lacking knowledge and understanding in the field of pulmonary hypertension associated to left heart disease (PH-LHD) that should be addressed in the future. Further research should be performed, in terms of pathobiology, and understanding the predisposition (genetic susceptibility and contributing factors) of the different phenotypes of this disorder. More clinical trials targeting new therapeutic options and specific PH therapies are warranted to help this increasing important patient group as the current guidelines recommend to only treat the underlying left-sided heart disease.

Intersection of Pulmonary Hypertension and Right Ventricular Dysfunction in Patients on Left Ventricular Assist Device Support: Is There a Role for Pulmonary Vasodilators?

Left ventricular assist devices (LVADs) improve survival and quality of life in patients with advanced heart failure. Despite these benefits, combined post- and precapillary pulmonary hypertension can be particularly problematic in patients on LVAD support, often exacerbating right ventricular (RV) dysfunction. Both persistently elevated pulmonary vascular resistance and RV dysfunction are associated with adverse outcomes, including death after LVAD. These observations have led to significant interest in the use of pulmonary vasodilators to treat pulmonary hypertension and preserve RV function among LVAD-supported patients. Although pulmonary vasodilators are commonly used for the treatment of pulmonary hypertension and RV dysfunction in LVADs, the benefits of this practice remain unclear. The purpose of this review is to highlight the current challenges in managing pulmonary vascular disease and RV dysfunction in patients with heart failure on LVAD support.

Phosphodiesterase 5 inhibitors for pulmonary hypertension

BACKGROUND

Pulmonary hypertension (PH) comprises a group of complex and heterogenous conditions, characterised by elevated pulmonary artery pressure, and which left untreated leads to right-heart failure and death. PH includes World Health Organisation (WHO) Group 1 pulmonary arterial hypertension (PAH); Group 2 consists of PH due to left-heart disease (PH-LHD); Group 3 comprises PH as a result of lung diseases or hypoxia, or both; Group 4 includes PH due to chronic thromboembolic occlusion of pulmonary vasculature (CTEPH), and Group 5 consists of cases of PH due to unclear and/or multifactorial mechanisms including haematological, systemic, or metabolic disorders. Phosphodiesterase type 5 (PDE5) inhibitors increase vasodilation and inhibit proliferation.

OBJECTIVES

To determine the efficacy of PDE5 inhibitors for pulmonary hypertension in adults and children.

SEARCH METHODS

We performed searches of CENTRAL, MEDLINE, Embase, CINAHL, and Web of Science up to 26 September 2018. We handsearched review articles, clinical trial registries, and reference lists of retrieved articles.

SELECTION CRITERIA

We included randomised controlled trials that compared any PDE5 inhibitor versus placebo, or any other PAH disease-specific therapies, for at least 12 weeks. We include separate analyses for each PH group.

DATA COLLECTION AND ANALYSIS

We imported studies identified by the search into a reference manager database. We retrieved the full-text versions of relevant studies, and two review authors independently extracted data. Primary outcomes were: change in WHO functional class, six-minute walk distance (6MWD), and mortality. Secondary outcomes were haemodynamic parameters, quality of life/health status, dyspnoea, clinical worsening (hospitalisation/intervention), and adverse events. When appropriate, we performed meta-analyses and subgroup analyses by severity of lung function, connective tissue disease diagnosis, and radiological pattern of fibrosis. We assessed the evidence using the GRADE approach and created 'Summary of findings' tables.

MAIN RESULTS

We included 36 studies with 2999 participants (with pulmonary hypertension from all causes) in the final review. Trials were conducted for 14 weeks on average, with some as long as 12 months. Two trials specifically included children.Nineteen trials included group 1 PAH participants. PAH participants treated with PDE5 inhibitors were more likely to improve their WHO functional class (odds ratio (OR) 8.59, 95% confidence interval (CI) 3.95 to 18.72; 4 trials, 282 participants), to walk 48 metres further in 6MWD (95% CI 40 to 56; 8 trials, 880 participants), and were 22% less likely to die over a mean duration of 14 weeks (95% CI 0.07 to 0.68; 8 trials, 1119 participants) compared to placebo (high-certainty evidence). The number needed to treat to prevent one additional death was 32 participants. There was an increased risk of adverse events with PDE5 inhibitors, especially headache (OR 1.97, 95% CI 1.33 to 2.92; 5 trials, 848 participants), gastrointestinal upset (OR 1.63, 95% CI 1.07 to 2.48; 5 trials, 848 participants), flushing (OR 4.12, 95% CI 1.83 to 9.26; 3 trials, 748 participants), and muscle aches and joint pains (OR 2.52, 95% CI 1.59 to 3.99; 4 trials, 792 participants).Data comparing PDE5 inhibitors to placebo whilst on other PAH-specific therapy were limited by the small number of included trials. Those PAH participants on PDE5 inhibitors plus combination therapy walked 19.66 metres further in six minutes (95% CI 9 to 30; 4 trials, 509 participants) compared to placebo (moderate-certainty evidence). There were limited trials comparing PDE5 inhibitors directly with other PAH-specific therapy (endothelin receptor antagonists (ERAs)). Those on PDE5 inhibitors walked 49 metres further than on ERAs (95% CI 4 to 95; 2 trials, 36 participants) (low-certainty evidence). There was no evidence of a difference in WHO functional class or mortality across both treatments.Five trials compared PDE5 inhibitors to placebo in PH secondary to left-heart disease (PH-LHD). The quality of data were low due to imprecision and inconsistency across trials. In those with PH-LHD there were reduced odds of an improvement in WHO functional class using PDE5 inhibitors compared to placebo (OR 0.53, 95% CI 0.32 to 0.87; 3 trials, 285 participants), and those using PDE5 inhibitors walked 34 metres further compared to placebo (95% CI 23 to 46; 3 trials, 284 participants). There was no evidence of a difference in mortality. Five trials compared PDE5 inhibitors to placebo in PH secondary to lung disease/hypoxia, mostly in COPD. Data were of low quality due to imprecision of effect and inconsistency across trials. There was a small improvement of 27 metres in 6MWD using PDE5 inhibitors compared to placebo in those with PH due to lung disease. There was no evidence of worsening hypoxia using PDE5 inhibitors, although data were limited. Three studies compared PDE5 inhibitors to placebo or other PAH-specific therapy in chronic thromboembolic disease. There was no significant difference in any outcomes. Data quality was low due to imprecision of effect and heterogeneity across trials.

AUTHORS' CONCLUSIONS

PDE5 inhibitors appear to have clear beneficial effects in group 1 PAH. Sildenafil, tadalafil and vardenafil are all efficacious in this clinical setting, and clinicians should consider the side-effect profile for each individual when choosing which PDE5 inhibitor to prescribe.While there appears to be some benefit for the use of PDE5 inhibitors in PH-left-heart disease, it is not clear based on the mostly small, short-term studies, which type of left-heart disease stands to benefit. These data suggest possible harm in valvular heart disease. There is no clear benefit for PDE5 inhibitors in pulmonary hypertension secondary to lung disease or chronic thromboembolic disease. Further research is required into the mechanisms of pulmonary hypertension secondary to left-heart disease, and cautious consideration of which subset of these patients may benefit from PDE5 inhibitors. Future trials in PH-LHD should be sufficiently powered, with long-term follow-up, and should include invasive haemodynamic data, WHO functional class, six-minute walk distance, and clinical worsening.