Pulmonary arterial pressure during rest and exercise in healthy subjects: a systematic review

Exploring the Potential of Quantum Dot-Sensitized Solar Cells: Innovation and Insights

Photovoltaic technologies have garnered significant attention towards generating renewable and clean energy from solar power. Quantum-dot-sensitized solar cells represent a promising third-generation photovoltaic technology that offers alternatives to conventional silicon-based solar cells due to their unique properties, their favourable optoelectronic properties for photovoltaic applications including simplified manufacturing, lower processing temperatures, enhanced flexibility, semi-transparent design, and a theoretical efficiency up to 44 %. The unique characteristic of tailoring the size and composition of quantum dots makes them valuable absorber materials capable of efficiently harnessing a broader range of the solar spectrum. The potential of quantum dot-sensitized solar cells to revolutionize the field of photovoltaic technology is a cause for optimism. However, the major limitation of the overall power conversion efficiency lies in their inability to absorb ultraviolet and near-infrared. Therefore, a photovoltaic technology that can effectively harness the entire solar spectrum becomes imperative. This review discusses the synthesis and light conversion mechanisms of these solar cells. Additionally, it offers an overview of the various advancements made in quantum dot-sensitized solar cells for enhancement in the efficiency of energy conversion. It focuses on the light-absorbing materials used, their efficiency, and the advantages and drawbacks of quantum dot solar cell technology.

Determinants of cardiac output in health and heart failure

Sustained physical exercise depends on delivery of oxygenated blood to exercising muscle. At least among healthy individuals, bulk transport of blood is tightly matched to metabolic demand, such that cardiac output increases by ∼6 L/min for every 1 L/min increase in oxygen uptake. Multiple factors contribute to the regulation of cardiac output, including central command, the exercise pressor reflex (EPR) and arterial baroreceptors. Pulmonary arterial and left ventricular pressures increase in proportion to the rise in cardiac output and exercise intensity. The right ventricle augments contractility to maintain ventricular-arterial (VA) coupling and lusitropy to facilitate venous return. Among patients with heart failure (HF), however, the ability to deliver blood to exercising muscle is compromised as a result of multiple abnormalities impacting EPR, ventricular contractility, haemodynamics and VA coupling. The purpose of this review is to provide an overview of the factors limiting exercise capacity and cardiac output among patients with HF compared to what is known about normal physiology among healthy individuals.

[Historical milestones in the study of pulmonary hypertension]

The article describes the historical aspects of the discovery of the pulmonary circulation and the study of pulmonary hypertension (PH) as a pathophysiological condition with a key hemodynamic characteristic - an increase in pressure in the pulmonary artery. The complexity of PH treatment is due to the association with various cardiovascular and respiratory diseases, which requires a multifaceted holistic interdisciplinary approach with the active participation of the physician and the patient. Currently, the guide for successful clinical practice are clinical guidelines covering the full range of diagnostic and therapeutic measures for various groups of PH. The development of guidelines is the result of a long way of studying morphology, pathophysiology, creating and researching of pathogenetic medical drugs, clinical observation of patients in the framework of studies and registries.

Pulmonary hypertension in pediatrics: from clinical suspicion to management

Pediatric pulmonary hypertension differs from adult pulmonary hypertension in many ways, including multifactorial etiologies and comorbidities that can impact diagnosis, response to therapy, and outcome. The main etiologies of pediatric PH are idiopathic pulmonary arterial hypertension (PAH), PAH associated with congenital heart disease (PAH-CDH) and developmental lung disorders. Thorough diagnostic evaluation is necessary to properly classify pulmonary hypertension, find a potential treatable cause, and guide therapy. Diagnosis still relies on invasive hemodynamics that require sedation in most children. Management of pediatric pulmonary hypertension is mainly guided by small-scale studies, expert opinion, and extrapolation of adult data considering the paucity of trials in this population. The aim of this review is to provide an up-to-date summary of current knowledge on pediatric pulmonary hypertension, covering diagnosis to management, and to highlight the key takeaways from the pediatric task force of the 7th World Symposium on Pulmonary Hypertension, particularly regarding classification modifications, risk stratification, and management. What is known: • Pediatric pulmonary hypertension is a rare condition, with the main etiologies being idiopathic, associated with congenital heart disease and developmental lung disorders. • A risk-oriented treatment approach is recommended, with lower-risk mortality as the therapeutic target. Treatment should be escalated if the treatment response is unsatisfactory. What is new: • Classification of pulmonary arterial hypertension associated with congenital heart disease is expanded beyond the concept of a shunt. • Risk stratification is refined through the use of 25 validated risk factors.

Combining hyperpolarized 129Xe MR imaging and spectroscopy to noninvasively estimate pulmonary vascular resistance

Hyperpolarized 129Xe MRI/MRS enables quantitative mapping of function in lung airspaces, membrane tissue, and red blood cells (RBCs) within the pulmonary capillaries. The RBC signal also exhibits cardiogenic oscillations that are reduced in precapillary pulmonary hypertension (PH). This effect is obscured in patients with concomitant defects in transfer from airspaces to RBCs, which increase RBC oscillation amplitudes. Here, we provide a framework for interpreting RBC oscillations and show their relationship to pulsatile blood flow, capillary blood volume, capillary compliance, and impedance of the capillary and venous circulation. This framework was first applied to characterize RBC oscillations in a cohort of subjects with pulmonary disease but no known PH (n = 129). 129Xe MRI of RBC transfer was used to estimate capillary blood volume, and as it decreased, RBC oscillations sharply increased ([Formula: see text] = 0.53), consistent with model predictions. Model-derived fit parameters were then used to estimate the distribution of pulmonary vascular resistance (PVR) across arterial, capillary, and venous circulation and to correct oscillations for RBC transfer defects. Seventy percent of PVR was estimated to arise from pulmonary arteries, 11% from capillaries, and 19% from veins. When tested in a second cohort of subjects who underwent 129Xe MRI/MRS and right heart catheterization (n = 40), oscillations corrected for capillary blood volume correlated moderately with PVR (r2 = 0.27, P = 0.0014). For every 1.96 Wood units (WU) increase in PVR, corrected oscillations decreased by 1 absolute percentage point. This work demonstrates that, although 129Xe-RBC oscillations are only indirectly sensitive to precapillary obstruction, corrected oscillations below 7.5% were 100% specific for elevated PVR.NEW & NOTEWORTHY Cardiogenic oscillations in the 129Xe red blood cell (RBC) resonance decrease in precapillary pulmonary hypertension (PH) but are enhanced when capillary blood volume is reduced. To separate these effects, we developed a physiological model that used 129Xe gas exchange MRI to estimate blood volume, which was used to correct oscillation amplitude measurements. Corrected amplitudes correlated significantly with pulmonary vascular resistance, highlighting the potential for future noninvasive detection of PH.

Intrathoracic pressure deviations attenuate left ventricular filling and stroke volume without pronounced myocardial mechanical alterations in healthy adults

Intrathoracic pressure modulates cardiac loading conditions, which then influence left ventricular (LV) chamber function, and may occur with underlying myocardial mechanical alterations. We investigated the independent effects of inspiratory negative and expiratory positive intrathoracic pressure on septal geometry, LV chamber function, and rotation, twist, and strain indices. After baseline, 20 healthy adults (11M/9F, 23 ± 4 yr) performed resistive breathing to manipulate inspiratory (-30, -20, -10 cmH2O) or expiratory (+10, +20 cmH2O) intrathoracic pressure. Echocardiography was used to acquire LV-focused two-dimensional (2-D) images, and mitral Doppler inflow and annular tissue velocity spectra. Images were analyzed for LV chamber volumes, tissue velocities, transmitral filling velocities, and speckle tracking-derived LV longitudinal, radial, and circumferential strain and strain-rate, basal and apical rotation, and twist. Across negative pressure trials, most profoundly at -30 cmH2O, we observed progressive end-diastolic septal flattening (3.9 ± 0.4 vs. 3.2 ± 0.4 cm, P < 0.05) and decreases in LV end-diastolic volume (103 ± 23 vs. 115 ± 25 mL, P < 0.05) and stroke volume, whereas end-systolic volume was unchanged. However, LV apical and basal rotation, twist (13.3° ± 3.6° vs. 13.9° ± 3.7°, P = 0.890), and circumferential, radial, and longitudinal strain indices were largely unchanged. During positive pressure trials, we observed main effects for septal flattening (P = 0.014) confined to inspiration, and modestly reduced LV end-diastolic volume (P < 0.001), end-systolic volume (P = 0.033), and stroke volume. Again, myocardial mechanics parameters changed little. Collectively, our data suggest that both positive and negative intrathoracic pressures can exacerbate direct ventricular interaction through opposing mechanisms that attenuate LV end-diastolic volume and stroke volume, but without specific changes in myocardial mechanics or mitral inflow.NEW & NOTEWORTHY Incrementally more negative or positive intrathoracic pressures, relative to normal dynamic breathing, progressively attenuate left ventricular end-diastolic volume and stroke volume in healthy younger adults. Incrementally more negative or positive intrathoracic pressures were each associated with progressive septal flattening during inspiration, indicating direct ventricular interaction. However, left ventricular transmitral inflow velocities, and myocardial rotation, twist, and circumferential, longitudinal, and radial strain parameters changed little.

Imaging Approach to Pulmonary Hypertension

Pulmonary hypertension is a rare but important clinical problem that presents a sometimes challenging diagnostic dilemma. The diagnosis of pulmonary hypertension relies on a combination of clinical testing and radiologic imaging, with chest computed tomography (CT) often serving as the primary imaging modality for comprehensive evaluation of the chest. Chest CT can be used to evaluate for causes of pulmonary hypertension including chronic lung disease, pulmonary artery obstruction, and congenital heart disease. Recognizing common appearances of these conditions will enable expedient diagnosis.

Revisiting Acute Decompensated Right Ventricle Failure in Pulmonary Arterial Hypertension

Pulmonary Arterial Hypertension (PAH) is a progressive vascular disease characterized by elevated Pulmonary Vascular Resistance (PVR) leading to Right Ventricular (RV) dysfunction and, ultimately, Right Heart Failure (RHF). Acute decompensation of PAH presents a life-threatening consequence marked by sudden worsening of clinical signs of right heart failure, systemic circulatory insufficiency, and multi-system organ failure. Clinicians are encountering more and more patients with PAH and RHF in the critical care units. These patients require admission and management in a critical care unit until they can be stabilized. The pathogenesis involves an imbalance between RV afterload and its adaptation capacity, ultimately resulting in RV dilation and failure. While the causes of acute decompensation remain subtle in many cases, infections, drug noncompliance, and pulmonary embolism are common culprits. Early identification of signs and symptoms of acute decompensation of RV failure, determination of possible etiology, and timely initiation of optimal treatment approaches are pivotal in avoiding detrimental outcomes. Optimization of pre-load and use of pulmonary vasodilators and inotropic agents are cornerstones of management. In refractory cases, mechanical circulatory support such as Extracorporeal Membrane Oxygenation (ECMO) or Right Ventricular Assist Devices (RVADs) may be necessary. Balloon Atrial Septostomy (BAS) serves as a bridge to definitive therapy, offering decompression of the right atrium and right ventricle. The prognosis of acute decompensated RV failure in PAH patients remains poor, highlighting the critical need for early diagnosis and intervention to improve outcomes. Currently, there are no strict standard guidelines to manage acute decompensated RV failure in PAH patients. We aim to revisit current evidence and practice trends in PAH and its acute decompensation.

Right Heart Failure in the Intensive Care Unit: Etiology, Pathogenesis, Diagnosis, and Treatment

Right heart (RH) failure carries a high rate of morbidity and mortality. Patients who present with RH failure often exhibit complex aberrant cardio-pulmonary physiology with varying presentations. The treatment of RH failure almost always requires care and management from an intensivist. Treatment options for RH failure patients continue to evolve rapidly with multiple options available, including different pharmacotherapies and mechanical circulatory support devices that target various components of the RH circulatory system. An understanding of the normal RH circulatory physiology, treatment, and support options for the RH failure patients is necessary for all intensivists to improve outcomes. The purpose of this review is to provide clinical guidance on the diagnosis and management of RH failure within the intensive care unit setting, and to highlight the different pathophysiological manifestations of RH failure, its hemodynamics, and treatment options available at the disposal of the intensivist.

Exercise Pulmonary Hypertension and Beyond: Insights in Exercise Pathophysiology in Pulmonary Arterial Hypertension (PAH) from Invasive Cardiopulmonary Exercise Testing

Pulmonary arterial hypertension (PAH) is a rare, progressive disease of the pulmonary vasculature that is associated with pulmonary vascular remodeling and right heart failure. While there have been recent advances both in understanding pathobiology and in diagnosis and therapeutic options, PAH remains a disease with significant delays in diagnosis and high morbidity and mortality. Information from invasive cardiopulmonary exercise testing (iCPET) presents an important opportunity to evaluate the dynamic interactions within and between the right heart circulatory system and the skeletal muscle during different loading conditions to enhance early diagnosis, phenotype disease subtypes, and personalize treatment in PAH given the shortcomings of contemporary diagnostic and therapeutic approaches. The purpose of this review is to present the current applications of iCPET in PAH and to discuss future applications of the testing methodology.

Pathophysiology of Group 3 Pulmonary Hypertension Associated with Lung Diseases and/or Hypoxia

Pulmonary hypertension associated with lung diseases and/or hypoxia is classified as group 3 in the clinical classification of pulmonary hypertension. The efficacy of existing selective pulmonary vasodilators for group 3 pulmonary hypertension is still unknown, and it is currently associated with a poor prognosis. The mechanisms by which pulmonary hypertension occurs include hypoxic pulmonary vasoconstriction, pulmonary vascular remodeling, a decrease in pulmonary vascular beds, endothelial dysfunction, endothelial-to-mesenchymal transition, mitochondrial dysfunction, oxidative stress, hypoxia-inducible factors (HIFs), inflammation, microRNA, and genetic predisposition. Among these, hypoxic pulmonary vasoconstriction and subsequent pulmonary vascular remodeling are characteristic factors involving the pulmonary vasculature and are the focus of this review. Several factors have been reported to mediate vascular remodeling induced by hypoxic pulmonary vasoconstriction, such as HIF-1α and mechanosensors, including TRP channels. New therapies that target novel molecules, such as mechanoreceptors, to inhibit vascular remodeling are awaited.

Sex differences in exercise-induced arterial hypoxemia and pulmonary edema following high-intensity exercise in highly trained endurance athletes

This study investigated sex differences in the development of pulmonary edema and exercise-induced arterial hypoxemia (EIAH) in well-trained endurance athletes during near-maximal exercise in a real-world setting. Twenty participants (10M vs. 10F; V̇O2peak: 69.3 (8.8) vs. 50.7 (4.1) ml∙kg-1∙min-1) underwent a maximal incremental treadmill test (visit 1) and a time trial on a steep trail (~2.5 km, ~800 m elevation gain) in North Vancouver (visit 2). Pulmonary edema was evaluated using handheld lung ultrasound ~10-15 min post-exercise and oxygen saturation (SpO2) was monitored using finger pulse oximetry. Males completed the time trial significantly faster than females (M: 31.5 (6.5) vs. F: 40.4 (7.5) min, p = 0.006), while females sustained a higher percentage of their visit 1 heart rate (M: 94 (1) vs. F: 96 (1) %max, p = 0.02). All participants developed EIAH, with no sex differences in end-exercise SpO2 (M: 89 (4) % vs. F: 90 (3) %, respectively, p = 0.35). There was no evidence of pulmonary edema, assessed through ultrasound b-line scores, with no differences between sexes (M: 0.3 (1.0) vs. F: 0.5 (1.5), respectively, p = 0.60). Pulmonary edema is an unlikely contributor to EIAH in endurance athletes performing near-maximal time trial exercise in a real-world setting.

The uses of right heart catheterization in cardio-pulmonary disease: State-of-the-art

The right heart catheterization (RHC) remains an important diagnostic tool for a spectrum of cardiovascular disease processes including pulmonary hypertension (PH), shock, valvular heart disease, and unexplained dyspnea. While it gained widespread utilization after its introduction, the role of the RHC has evolved to provide valuable information for the management of advanced therapies in heart failure (HF) and cardiogenic shock (CS) to name a few. In this review, we provide a comprehensive overview on the indications, utilization, complications, interpretation, and calculations associated with RHC.

Impact of body posture on pulmonary diffusing capacity at rest and during exercise in endurance-trained and untrained individuals

Endurance-trained athletes exhibit a greater diffusing capacity for carbon monoxide (DLCO) at rest and during exercise as compared with untrained individuals; however, the mechanism(s) are unclear. The supine position translocates blood centrally and can be used to investigate DLCO responses independent of metabolic rate. We hypothesized that endurance-trained individuals would have a greater DLCO response to postural change at rest as compared with untrained and that the supine position would elicit a greater DLCO response as compared with the upright position during exercise in both groups. Fourteen endurance-trained (Trained) individuals (V̇o2peak: 61.1 ± 4.4 mL·kg-1·min-1) and 14 untrained individuals (V̇o2peak: 37.4 ± 3.0 mL·kg-1·min-1) completed DLCO maneuvers at rest and during exercise in the upright and supine position. At rest, there was a significant group-by-position interaction (P = 0.02) effect on DLCO with post hoc analysis determining DLCO increased from upright to supine position in Trained (P < 0.01), but not untrained (P = 0.58). There was no effect of position on exercising DLCO (P = 0.16) regardless of group; however, pulmonary capillary blood volume (VC) was increased with supine exercise (P = 0.03). There was an apparent plateau in DLCO and VC in the Trained group near-maximal exercise as Trained failed to increase DLCO (P = 0.25) and Vc (P = 0.46) up to near-maximal exercise. Trained individuals demonstrate greater DLCO recruitment with postural change at rest suggesting a greater ability to recruit/distend the pulmonary microvasculature. However, the supine position did not augment DLCO as compared with upright position in Trained individuals near-maximal exercise, suggesting a plateau may be reached at maximal exercise.NEW & NOTEWORTHY We demonstrate that the supine position increases resting DLCO significantly more in endurance-trained individuals as compared with untrained individuals. Furthermore, the supine position increases pulmonary capillary blood volume, but not diffusing capacity during exercise. Lastly, there was an apparent plateau in DLCO and VC in the Trained group suggesting the pulmonary microvasculature may reach a morphological limit.

Shifting Paradigms in the Management of Pulmonary Hypertension

Pulmonary arterial hypertension (PAH) is a long-term condition characterised by increased resistance to blood flow in the pulmonary circulation. The disease has a progressive course and is associated with a poor prognosis. Without treatment, PAH is associated with mortality in <3 years. Over the past decade, many advances have been made in revising the haemodynamic definition, clinical classification, risk calculation score, treatment options etc. Suggestions from the Sixth World Symposium on Pulmonary Hypertension were incorporated into a literature review that was included in the European Society of Cardiology/European Respiratory Society (ESC/ERS)'s most recent iteration of their guidelines in 2022. The traditional cut-off for pulmonary hypertension (PH), i.e., mean pulmonary artery pressure (mPAP) >25 mm Hg, has been challenged by observational cohort studies, which have shown poor outcomes for values of 21-24 mmHg; the new consensus is that PH is defined at mPAP >20 mm Hg. Although the gold standard for diagnosis and the major source of therapy guidance continues to be right cardiac catheterisation, echocardiography remains the initial test of choice. A multidisciplinary approach is highly recommended when treating PH patients and careful evaluation of patients will aid in proper diagnosis and prognosis. Pharmacotherapy for PAH has seen a paradigm shift with the successful use of newer agents in more extensive, longer and more inclusive trials driven by hard endpoints. Macitentan, selexipag and riociguat are three oral agents that have shown astounding success in PAH randomised studies in the past decade. Upfront combination therapy with two agents is now becoming the norm (following the AMBITION, OPTIMA and ITALY trials) and the momentum is shifting towards triple therapy as for essential hypertension. More recently, inhaled treprostinil was shown to improve exercise capacity in PH associated with interstitial lung disease in the phase III INCREASE study and has been granted regulatory approval for World Health Organization group 3 PH. A new class of drug, sotatercept (a tumour growth factor-β signalling inhibitor), has also been recently approved by the Food and Drug Administration for management of PAH based on positive results from the phase III STELLAR study. Pulmonary artery denervation and balloon pulmonary angioplasty have emerged as viable alternatives in PH that are resistant to drug therapy. This article aims to summarise the key changes and recent advances in diagnosis and managing PH in general, with an emphasis on certain subgroups.

The Diagnostic Accuracy of an Electrocardiogram in Pulmonary Hypertension and the Role of "R V1, V2 + S I, aVL - S V1"

Background: Pulmonary hypertension (PH) can cause characteristic electrocardiographic (ECG) changes due to right ventricular hypertrophy and/or strain. The aims of the present study were to explore the diagnostic accuracy of ECG parameters for the diagnosis of PH, applying the recently adjusted mean pulmonary artery pressure (mPAP) threshold of >20 mmHg, and to determine the role of "R V1, V2 + S I, aVL - S V1". Methods: Between July 2012 and November 2023, 100 patients without PH, with pulmonary arterial hypertension, or with chronic thromboembolic pulmonary hypertension were retrospectively enrolled. Results: The sensitivity and specificity of the ECG parameters for the diagnosis of PH varied from 3 to 98% and from 3 to 100% (means: 39% and 87%). After optimising the parameters' cut-offs, the mean sensitivity (39% to 66%) increased significantly but the mean specificity (87% to 74%) slightly decreased. "R V1, V2 + S I, aVL - S V1" was able to predict an mPAP >20 mmHg (OR: 34.33; p < 0.001) and a pulmonary vascular resistance >5 WU (OR: 17.14, p < 0.001) but could not predict all-cause mortality. Conclusions: Even with improved cut-offs, ECG parameters alone are not able to reliably diagnose or exclude PH because of their low sensitivity. However, they still might be helpful to reveal a suspicion of PH, especially in early diagnostic stages, e.g., in primary care with general practitioners or non-specialised cardiologists and pulmonologists. "R V1, V2 + S I, aVL - S V1" was able to predict the diagnosis of (severe) PH but could not predict all-cause mortality. Nevertheless, it can still be useful in risk stratification.

Prognostic relevance of exercise pulmonary hypertension: results of the multicentre PEX-NET Clinical Research Collaboration

BACKGROUND

Exercise pulmonary hypertension (PH) was defined by a mean pulmonary arterial pressure (mPAP)/cardiac output (CO) slope >3 mmHg·min·L-1 between rest and exercise in the 2022 European Society of Cardiology/European Respiratory Society PH guidelines. However, large, multicentre studies on the prognostic relevance of exercise haemodynamics and its added value to resting haemodynamics are missing.

PATIENTS AND METHODS

The PEX-NET (Pulmonary Haemodynamics during Exercise Network) registry enrolled patients who underwent clinically indicated right heart catheterisations both at rest and ergometer exercise from 23 PH centres worldwide. In this retrospective analysis we included subjects with resting mPAP <25 mmHg and complete haemodynamic data at rest and exercise in the same body position. Mixed effects Cox proportional hazard models with random effect centre were applied to identify independent markers of prognosis among the haemodynamic parameters.

RESULTS

We included 764 patients (64% females; median (interquartile range) age 59 (46-69) years and mPAP 17 (14-20) mmHg). Median (range) observation time was 6.8 (0.1-15.9) years and 87 patients (11%) died during follow-up. After adjustment for age, sex, haemoglobin level and resting haemodynamics, CO (hazard ratio (HR) 0.85, 95% CI 0.77-0.93; p=0.001) and transpulmonary gradient (HR 1.04, 95% CI 1.00-1.08; p=0.044) at peak exercise and the mPAP/CO slope (HR 1.12, 95% CI 1.06-1.18; p<0.001) were the only independent predictors of prognosis. Patients with a mPAP/CO slope >3 mmHg·min·L-1 had significantly worse survival compared to those with a mPAP/CO slope ≤3 mmHg·min·L-1 (HR 2.04, 95% CI 1.16-3.58; p=0.013).

CONCLUSION

The mPAP/CO slope is a robust and independent predictor of prognosis in patients with normal or mildly elevated resting PAP that provides prognostic information beyond resting haemodynamics and appears suitable to define exercise PH.

Pulmonary hypertension in patients affected by sleep-related breathing disorders: up to date from the literature

Sleep-related breathing disorders (SBD) are conditions of abnormal and difficult respiration during sleep, including chronic snoring, obstructive sleep apnea (OSA), central sleep apnea (CSA), sleep-related hypoventilation disorders and sleep-related hypoxemia. Some of them have a limited impact on health, but others (e.g., OSA) can have serious consequences, because of their dangerous effects on sleep and the hematic balance of oxygen and carbon dioxide. According to several population-based studies, prevalence of OSA is relatively high, approximately 3-7% for adult males and 2-5% for adult females in the general population. However, methodological differences and difficulties in characterizing this syndrome yielded to variability in estimates. Moreover, it is estimated that only about 40% of patients with OSA are diagnosed, which can lead to underestimation of disease prevalence. OSA is directly correlated with age and male sex and to risk factors such as obesity. Several studies found that OSA is associated with an increased risk of diabetes, some cancer types, cardiovascular and cerebrovascular diseases, such as hypertension, coronary artery disease and stroke. Pulmonary hypertension (PH), a noted cardiovascular disease, is significantly associated with sleep-related breathing disorders and lot of scientific studies published in the literature demonstrated a strong link between these conditions and the development of pulmonary hypertension PH. PH is relatively less common than sleep-related breathing disorders. The purpose of this systematic review is to analyze both the current knowledge around the consequences that SBD may have on pulmonary hemodynamics and the effects resulting from pharmacological and non-pharmacological treatments of SDB on PH.

Seated Pulmonary Artery Pressure Monitoring in Patients With Heart Failure: Results of the PROACTIVE-HF Trial

BACKGROUND

Monitoring supine pulmonary artery pressures to guide heart failure (HF) management has reduced HF hospitalizations in select patients.

OBJECTIVES

The purpose of this study was to evaluate the effect of managing seated mean pulmonary artery pressure (mPAP) with the Cordella Pulmonary Artery sensor on outcomes in patients with HF.

METHODS

Following GUIDE-HF (Hemodynamic-GUIDEd Management of Heart Failure Trial), with U.S. Food and Drug Administration input, PROACTIVE-HF (A Prospective, Multi-Center, Open Label, Single Arm Clinical Trial Evaluating the Safety and Efficacy of the Cordella Pulmonary Artery Sensor System in NYHA Class III Heart Failure Patients trial) was changed from a randomized to a single-arm, open label trial, conducted at 75 centers in the USA and Europe. Eligible patients had chronic HF with NYHA functional class III symptoms, irrespective of the ejection fraction, and recent HF hospitalization and/or elevated natriuretic peptides. The primary effectiveness endpoint at 6 months required the HF hospitalization or all-cause mortality rate to be lower than a performance goal of 0.43 events/patient, established from previous hemodynamic monitoring trials. Primary safety endpoints at 6 months were freedom from device- or system-related complications or pressure sensor failure.

RESULTS

Between February 7, 2020, and March 31, 2023, 456 patients were successfully implanted in modified intent-to-treat cohort. The 6-month event rate was 0.15 (95% CI: 0.12-0.20) which was significantly lower than performance goal (0.15 vs 0.43; P < 0.0001). Freedom from device- or system-related complications was 99.2% and freedom from sensor failure was 99.8% through 6 months.

CONCLUSIONS

Remote management of seated mPAP is safe and results in a low rate of HF hospitalizations and mortality. These results support the use of seated mPAP monitoring and extend the growing body of evidence that pulmonary artery pressure-guided management improves outcomes in heart failure. (Multi-Center, Open Label, Single Arm Clinical Trial Evaluating the Safety and Efficacy of the Cordella Pulmonary Artery Sensor System in NYHA Class III Heart Failure Patients trial [PROACTIVE-HF]; NCT04089059).

New diagnostic criteria and current issues for pulmonary hypertension

In 2022, the European Society of Cardiology (ESC) and the European Respiratory Society (ERS) proposed new diagnostic criteria for pulmonary hypertension (PH). These criteria include significant changes to the definitions of pulmonary hemodynamic indices. Specifically, the threshold for mean pulmonary artery pressure (mPAP) has been lowered from ≥25 mmHg to >20 mmHg, and the threshold for pulmonary vascular resistance (PVR) has been adjusted from ≥3 Wood units (WU) to >2 WU. Additionally, the diagnostic criterion for exercise-induced PH has been reintroduced. To differentiate between non-severe and severe PH associated with lung disease, a differential threshold of 5 WU for PVR has been proposed. However, the threshold for mean pulmonary artery wedge pressure (PAWP) remains unchanged. While these new criteria could provide a more refined approach to clinical practice, they may also raise clinical concerns and questions regarding the diagnosis and management of PH.

Pulmonary hypertension and lung transplantation waitlist outcomes for hypersensitivity pneumonitis

Background

Hypersensitivity pneumonitis is an interstitial lung disease that can progress to pulmonary hypertension which increases mortality. The European Society of Cardiology recently reduced the diagnostic criteria for precapillary pulmonary hypertension from mean pulmonary artery pressure ≥25mmHg to ≥20mmHg and pulmonary vascular resistance from ≥3Wu to ≥2Wu.

Methods

We conducted a retrospective cohort study of the Scientific Registry of Transplant Recipients.1175 hypersensitivity pneumonitis patients listed for lung transplantation were divided into three groups based on the presence of precapillary pulmonary hypertension; those with pre-capillary pulmonary hypertension based on old criteria, new criteria, and those without precapillary pulmonary hypertension based on either criterion. The individual components of precapillary pulmonary hypertension were also assessed with three mean pulmonary artery pressure groups (≤20mmHg, >20mmHg to <25mmHg, ≥25 mmHg) and three pulmonary vascular resistance groups (≤2Wu, >2Wu to <3Wu, ≥3Wu). Survival analysis was performed.

Results

Kaplan-Meier analysis showed a difference in waitlist survival probability among the mean pulmonary artery pressure groups and among the pulmonary vascular resistance groups driven by the most severe groups. Multivariate Cox regression showed no difference between the various pre-capillary pulmonary hypertension groups. Pulmonary vascular resistance ≥3Wu was associated with increased waitlist mortality.

Conclusions

The new thresholds of mean pulmonary artery pressure and pulmonary vascular resistance do not appear to prognosticate waitlist outcomes when combined. PVR ≥3Wu is associated with worse waitlist outcomes and may be useful in prognostication.

Evidence and unresolved questions in pulmonary hypertension: Insights from the 5th French Pulmonary Hypertension Network Meeting

Pulmonary hypertension (PH) continues to present significant challenges to the medical community, both in terms of diagnosis and treatment. The advent of the updated 2022 European Society of Cardiology (ESC) and European Respiratory Society (ERS) guidelines has introduced pivotal changes that reflect the rapidly advancing understanding of this complex disease. These changes include a revised definition of PH, updates to the classification system, and treatment algorithm. While these guidelines offer a critical framework for the management of PH, they have also sparked new discussions and questions. The 5th French Pulmonary Hypertension Network Meeting (Le Kremlin-Bicêtre, France, 2023), addressed these emergent questions and fostering a deeper understanding of the disease's multifaceted nature. These discussions were not limited to theoretical advancements but extended into the practical realms of patient management, highlighting the challenges and opportunities in applying the latest guidelines to clinical practice.

Efficacy of balloon pulmonary angioplasty in patients with chronic thromboembolic pulmonary disease and exercise pulmonary hypertension

BACKGROUND

The efficacy of balloon pulmonary angioplasty (BPA) in patients with chronic thromboembolic disease (CTEPD) without pulmonary hypertension (PH) remains unknown. Exercise PH (Ex-PH) is associated with impaired exercise capacity, even when pulmonary hemodynamics are normal at rest. We hypothesized that patients with Ex-PH could be the candidates for BPA. This study aimed to determine the prevalence and clinical profiles of Ex-PH and the effect of BPA on oxygenation and Ex-PH in patients with CTEPD and mean pulmonary arterial pressure (mPAP) ≤ 20 mmHg.

METHODS

We retrospectively reviewed 23 patients (median age 65 years) with CTEPD and mPAP ≤20 mmHg at rest who underwent cardiopulmonary exercise testing with right heart catheterization. Patients were divided into two groups: Ex-PH, defined by an mPAP/cardiac output (CO) slope (mPAP/CO slope) > 3.0, and non-Ex-PH.

RESULTS

Overall, 12 and 11 patients were identified as Ex-PH and non-Ex-PH groups, respectively. There were no significant differences in clinical parameters, including hemodynamics at rest, and blood gas analysis between Ex-PH and non-Ex-PH groups. Among 9 patients with Ex-PH, BPA improved World Health Organization-functional class and PaO2 at rest and was associated with a decrease in the mPAP/CO slope. All 3 patients discontinued LTOT after BPA. There were no significant complications during each BPA session.

CONCLUSIONS

Ex-PH was common among patients with CTEPD without PH. BPA could improve symptoms, oxygenation, and exercising hemodynamics in patients with CTEPD and Ex-PH.

Pulmonary Artery Denervation: An Emerging Treatment for Pulmonary Hypertension

Pulmonary hypertension (PH) is a debilitating disease with a poor overall prognosis. Pulmonary artery denervation (PADN) has emerged as a promising new treatment which has been shown to improve hemodynamics, functionality, and REVEAL scores for patients with PH. This article reviews notable updates in the management of PH since the 6th World Symposium on PH, the pathophysiology of PH, how PADN may work given the pathophysiology of PH, and focuses on evidence from the eleven studies supporting the use of PADN from trials that include human participants.

Pulmonary hypertension associated with left heart disease

Left heart disease (LHD) is the most common cause of pulmonary hypertension (PH), which may be classified further as isolated post-capillary (ipcPH) or combined post- and pre-capillary PH (cpcPH). The 7th World Symposium on Pulmonary Hypertension PH-LHD task force reviewed newly reported randomised clinical trials and contemplated novel opportunities for improving outcome. Results from major randomised clinical trials reinforced prior recommendations against the use of pulmonary arterial hypertension therapy in PH-LHD outside of clinical trials, and suggested possible harm. Greater focus on phenotyping was viewed as one general strategy by which to ultimately improve clinical outcomes. This is potentially achievable by individualising ipcPH versus cpcPH diagnosis for patients with pulmonary arterial wedge pressure within a diagnostic grey zone (12-18 mmHg), and through a newly developed PH-LHD staging system. In this model, PH accompanies LHD across four stages (A=at risk, B=structural heart disease, C=symptomatic heart disease, D=advanced), with each stage characterised by progression in clinical characteristics, haemodynamics and potential therapeutic strategies. Along these lines, the task force proposed disaggregating PH-LHD to emphasise specific subtypes for which PH prevalence, pathophysiology and treatment are unique. This includes re-interpreting mitral and aortic valve stenosis through a contemporary lens, and focusing on PH within the hypertrophic cardiomyopathy and amyloid cardiomyopathy clinical spectra. Furthermore, appreciating LHD in the profile of PH patients with chronic lung disease and chronic thromboembolic pulmonary disease is essential. However, engaging LHD patients in clinical research more broadly is likely to require novel methodologies such as pragmatic trials and may benefit from next-generation analytics to interpret results.

Deep phenotyping of unaffected carriers of pathogenic BMPR2 variants screened for pulmonary arterial hypertension

INTRODUCTION

Pathogenic variants in the gene encoding for BMPR2 are a major genetic risk factor for heritable pulmonary arterial hypertension. Owing to incomplete penetrance, deep phenotyping of unaffected carriers of a pathogenic BMPR2 variant through multimodality screening may aid in early diagnosis and identify susceptibility traits for future development of pulmonary arterial hypertension.

METHODS

28 unaffected carriers (44±16 years, 57% female) and 21 healthy controls (44±18 years, 48% female) underwent annual screening, including cardiac magnetic resonance imaging, transthoracic echocardiography, cardiopulmonary exercise testing and right heart catheterisation. Right ventricular pressure-volume loops were constructed to assess load-independent contractility and compared with a healthy control group. A transgenic Bmpr2Δ71Ex1/+ rat model was employed to validate findings from humans.

RESULTS

Unaffected carriers had lower indexed right ventricular end-diastolic (79.5±17.6 mL·m-2 versus 62.7±15.3 mL·m-2; p=0.001), end-systolic (34.2±10.5 mL·m-2 versus 27.1±8.3 mL·m-2; p=0.014) and left ventricular end-diastolic (68.9±14.1 mL·m-2 versus 58.5±10.7 mL·m-2; p=0.007) volumes than control subjects. Bmpr2Δ71Ex1/+ rats were also observed to have smaller cardiac volumes than wild-type rats. Pressure-volume loop analysis showed that unaffected carriers had significantly higher afterload (arterial elastance 0.15±0.06 versus 0.27±0.08 mmHg·mL-1; p<0.001) and end-systolic elastance (0.28±0.07 versus 0.35±0.10 mmHg·mL-1; p=0.047) in addition to lower right ventricular pulmonary artery coupling (end-systolic elastance/arterial elastance 2.24±1.03 versus 1.36±0.37; p=0.006). During the 4-year follow-up period, two unaffected carriers developed pulmonary arterial hypertension, with normal N-terminal pro-brain natriuretic peptide and transthoracic echocardiography indices at diagnosis.

CONCLUSION

Unaffected BMPR2 mutation carriers have an altered cardiac phenotype mimicked in Bmpr2Δ71Ex1/+ transgenic rats. Future efforts to establish an effective screening protocol for individuals at risk for developing pulmonary arterial hypertension warrant longer follow-up periods.

The spectrum of systemic sclerosis-associated pulmonary hypertension: Insights from the ASPIRE registry

BACKGROUND

There are limited data assessing the spectrum of systemic sclerosis-associated pulmonary hypertension (PH).

METHODS

Data for 912 systemic sclerosis patients assessed between 2000 and 2020 were retrieved from the Assessing the Spectrum of Pulmonary hypertension Identified at a REferral centre (ASPIRE) registry and classified based on 2022 European Society of Cardiology/European Respiratory Society (ESC/ERS) guidelines and multimodality investigations.

RESULTS

Reduction in pulmonary vascular resistance (PVR) diagnostic threshold to >2WU resulted in a 19% increase in precapillary PH diagnoses. Patients with PVR ≤2WU had superior survival to PVR >2-3WU which was similar to PVR >3-4WU. Survival in pulmonary arterial hypertension (PAH) was superior to PH associated with lung disease. However, patients with mild parenchymal disease on CT had similar characteristics and outcomes to patients without lung disease. Combined pre- and postcapillary PH had significantly poorer survival than isolated postcapillary PH. Patients with mean pulmonary arterial wedge pressure (PAWP) 13-15 mm Hg had similar haemodynamics and left atrial volumes to those with PAWP >15 mm Hg. Unclassified-PH had more frequently dilated left atria and higher PAWP than PAH. Although Unclassified-PH had a similar survival to No-PH, 36% were subsequently diagnosed with PAH or PH associated with left heart disease. The presence of 2-3 radiological signs of pulmonary veno-occlusive disease was noted in 7% of PAH patients and was associated with worse survival. Improvement in incremental shuttle walking distance of ≥30 m following initiation of PAH therapy was associated with superior survival. PAH patients diagnosed after 2011 had greater use of combination therapy and superior survival.

CONCLUSION

A number of systemic sclerosis PH phenotypes can be recognized and characterized using haemodynamics, lung function and multimodality imaging.

Chronic thromboembolic pulmonary disease

Chronic thromboembolic pulmonary hypertension is a complication of pulmonary embolism and a treatable cause of pulmonary hypertension. The pathology is a unique combination of mechanical obstruction due to failure of clot resolution, and a variable degree of microvascular disease, that both contribute to pulmonary vascular resistance. Accordingly, multiple treatments have been developed to target the disease components. However, accurate diagnosis is often delayed. Evaluation includes high-quality imaging modalities, necessary for disease confirmation and for appropriate treatment planning. All patients with chronic thromboembolic pulmonary disease, and especially those with pulmonary hypertension, should be referred to expert centres for multidisciplinary team decision on treatment. The first decision remains assessment of operability, and the best improvement in symptoms and survival is achieved by the mechanical therapies, pulmonary endarterectomy and balloon pulmonary angioplasty. With the advances in multimodal therapies, excellent outcomes can be achieved with 3-year survival of >90%.

Exercise pulmonary hypertension in chronic thromboembolic pulmonary disease: A right heart catheterization study

Many patients with chronic thromboembolic pulmonary disease (CTEPD) suffer from exertional dyspnea. It is unclear if CTEPD is associated with exercise pulmonary hypertension (ePH). This cross-sectional study aimed to determine the occurrence of ePH in patients with CTEPD and to identify the haemodynamic changes during exercise. We recruited 36 patients with persistent dyspnoea and residual perfusion defects by ventilation/perfusion scintigraphy from a large cohort of patients with previous pulmonary embolism. All patients underwent exercise right heart catheterization before being classified into the following groups: (1) CTEPD without ePH; comprising patients with normal mean pulmonary artery pressure (mPAP) of ≤20 mmHg, but with mPAP/cardiac output (CO) slope of ≤3 mmHg/L/min, (2) CTEPD with ePH (CTEPD-ePH); those with CTEPD with an mPAP/CO slope of >3 mmHg/L/min, (3) chronic thromboembolic pulmonary hypertension (CTEPH); those with mPAP >20 mmHg, pulmonary arterial wedge pressure (PAWP) ≤ 15 mmHg and pulmonary vascular resistance >2 WU. The postcapillary contribution during exercise was considered present if the PAWP/CO slope of >2 mmHg/L/min. CTEPD without resting pulmonary hypertension (PH) was present in 29 (81%) of the 36 patients, of whom six (21%) had ePH, while five (14%) had CTEPH. Two patients had unclassified PH. Two (33%) of the six patients with CTEPD-ePH had a PAWP/CO slope of >2 mmHg/L/min, compared with two (40%) of the five of those with CTEPH. In conclusion, about 20% of patients with CTEPD and exertional dyspnoea had ePH. Exercise right heart catheterization revealed a notable proportion of patients with postcapillary contribution.

Definition, classification and diagnosis of pulmonary hypertension

Pulmonary hypertension (PH) is a haemodynamic condition characterised by elevation of mean pulmonary arterial pressure (mPAP) >20 mmHg, assessed by right heart catheterisation. Pulmonary arterial wedge pressure (PAWP) and pulmonary vascular resistance (PVR) distinguish pre-capillary PH (PAWP ≤15 mmHg, PVR >2 Wood Units (WU)), isolated post-capillary PH (PAWP >15 mmHg, PVR ≤2 WU) and combined post- and pre-capillary PH (PAWP >15 mmHg, PVR >2 WU). Exercise PH is a haemodynamic condition describing a normal mPAP at rest with an abnormal increase of mPAP during exercise, defined as a mPAP/cardiac output slope >3 mmHg/L/min between rest and exercise. The core structure of the clinical classification of PH has been retained, including the five major groups. However, some changes are presented herewith, such as the re-introduction of "long-term responders to calcium channel blockers" as a subgroup of idiopathic pulmonary arterial hypertension, the addition of subgroups in group 2 PH and the differentiation of group 3 PH subgroups based on pulmonary diseases instead of functional abnormalities. Mitomycin-C and carfilzomib have been added to the list of drugs with "definite association" with PAH. For diagnosis of PH, we propose a stepwise approach with the main aim of discerning those patients who need to be referred to a PH centre and who should undergo invasive haemodynamic assessment. In case of high probability of severe pulmonary vascular disease, especially if there are signs of right heart failure, a fast-track referral to a PH centre is recommended at any point during the clinical workup.

Post-capillary pulmonary hypertension in heart failure: impact of current definition in the PH-HF multicentre study

BACKGROUND AND AIMS

Based on retrospective studies, the 2022 European guidelines changed the definition of post-capillary pulmonary hypertension (pcPH) in heart failure (HF) by lowering the level of mean pulmonary artery pressure (mPAP) and pulmonary vascular resistance (PVR). However, the impact of this definition and its prognostic value has never been evaluated prospectively.

METHODS

Stable left HF patients with the need for right heart catheterization were enrolled from 2010 to 2018 and prospectively followed up in this multicentre study. The impact of the successive pcPH definitions on pcPH prevalence and subgroup [i.e. isolated (IpcPH) vs. combined pcPH (CpcPH)] was evaluated. Multivariable Cox regression analysis was used to assess the prognostic value of mPAP and PVR on all-cause death or hospitalization for HF (primary outcome).

RESULTS

Included were 662 HF patients were (median age 63 years, 60% male). Lowering mPAP from 25 to 20 mmHg resulted in +10% increase in pcPH prevalence, whereas lowering PVR from 3 to 2 resulted in +60% increase in CpcPH prevalence (with significant net reclassification improvement for the primary outcome). In multivariable analysis, both mPAP and PVR remained associated with the primary outcome [hazard ratio (HR) 1.02, 95% confidence interval (CI) 1.00-1.03, P = .01; HR 1.07, 95% CI 1.00-1.14, P = .03]. The best PVR threshold associated with the primary outcome was around 2.2 WU. Using the 2022 definition, pcPH patients had worse survival compared with HF patients without pcPH (log-rank, P = .02) as well as CpcPH compared with IpcPH (log-rank, P = .003).

CONCLUSIONS

This study is the first emphasizing the impact of the new pcPH definition on CpcPH prevalence and validating the prognostic value of mPAP > 20 mmHg and PVR > 2 WU among HF patients.

Chronic thromboembolic pulmonary hypertension: the diagnostic assessment

Chronic Thromboembolic Pulmonary Hypertension (CTEPH) presents a significant diagnostic challenge due to its complex and often nonspecific clinical manifestations. This review outlines a comprehensive approach to the diagnostic assessment of CTEPH, emphasizing the importance of a high index of suspicion in patients with unexplained dyspnea or persistent symptoms post-acute pulmonary embolism. We discuss the pivotal role of multimodal imaging, including echocardiography, ventilation/perfusion scans, CT pulmonary angiography, and magnetic resonance imaging, in the identification and confirmation of CTEPH. Furthermore, the review highlights the essential function of right heart catheterization in validating the hemodynamic parameters indicative of CTEPH, establishing its definitive diagnosis. Advances in diagnostic technologies and the integration of a multidisciplinary approach are critical for the timely and accurate diagnosis of CTEPH, facilitating early therapeutic intervention and improving patient outcomes. This manuscript aims to equip clinicians with the knowledge and tools necessary for the efficient diagnostic workflow of CTEPH, promoting awareness and understanding of this potentially treatable cause of pulmonary hypertension.

Comparison of Contemporary Risk Scores in All Groups of Pulmonary Hypertension: A Pulmonary Vascular Research Institute GoDeep Meta-Registry Analysis

BACKGROUND

Pulmonary hypertension (PH) is a heterogeneous disease with a poor prognosis. Accurate risk stratification is essential for guiding treatment decisions in pulmonary arterial hypertension (PAH). Although various risk models have been developed for PAH, their comparative prognostic potential requires further exploration. Additionally, the applicability of risk scores in PH groups beyond group 1 remains to be investigated.

RESEARCH QUESTION

Are risk scores originally developed for PAH predictive in PH groups 1 through 4?

STUDY DESIGN AND METHODS

We conducted a comprehensive analysis of outcomes among patients with incident PH enrolled in the multicenter worldwide Pulmonary Vascular Research Institute GoDeep meta-registry. Analyses were performed across PH groups 1 through 4 and further subgroups to evaluate the predictive value of PAH risk scores, including the Registry to Evaluate Early and Long-Term PAH Disease Mangement (REVEAL) Lite 2, REVEAL 2.0, European Society of Cardiology/European Respiratory Society 2022, Comparative, Prospective Registry of Newly Initiated Therapies for Pulmonary Hypertension (COMPERA) 3-strata, and COMPERA 4-strata.

RESULTS

Eight thousand five hundred sixty-five patients were included in the study, of whom 3,537 patients were assigned to group 1 PH, whereas 1,807 patients, 1,635 patients, and 1,586 patients were assigned to group 2 PH, group 3 PH, and group 4 PH, respectively. Pulmonary hemodynamics were impaired with median mean pulmonary arterial pressure of 42 mm Hg (interquartile range, 33-52 mm Hg) and pulmonary vascular resistance of 7 Wood units (WU) (interquartile range, 4-11 WU). All risk scores were prognostic in the entire PH population and in each of the PH groups 1 through 4. The REVEAL scores, when used as continuous prediction models, demonstrated the highest statistical prognostic power and granularity; the COMPERA 4-strata risk score provided subdifferentiation of the intermediate-risk group. Similar results were obtained when separately analyzing various subgroups (PH subgroups 1.1, 1.4.1, and 1.4.4; PH subgroups 3.1 and 3.2; group 2 with isolated postcapillary PH vs combined precapillary and postcapillary PH; patients of all groups with concomitant cardiac comorbidities; and severe [> 5 WU] vs nonsevere PH).

INTERPRETATION

This comprehensive study with real-world data from 15 PH centers showed that PAH-designed risk scores possess predictive power in a large PH cohort, whether considered as common to the group or calculated separately for each PH group (1-4) and various subgroups.

TRIAL REGISTRY

ClinicalTrials.gov; No.: NCT05329714; URL: www.

CLINICALTRIALS

gov.

Pulmonary vascular diseases at high altitude - is it safe to live in the mountains?

PURPOSE OF REVIEW

This review addresses the concern of the health effects associated with high-altitude living and chronic hypoxia with a focus on pulmonary hypertension. With an increasing global population residing at high altitudes, understanding these effects is crucial for public health interventions and clinical management.

RECENT FINDINGS

Recent literature on the long-term effects of high-altitude residence and chronic hypoxia is comprehensively summarized. Key themes include the mechanisms of hypoxic pulmonary vasoconstriction, the development of pulmonary hypertension, and challenges in distinguishing altitude-related pulmonary hypertension and classical pulmonary vascular diseases, as found at a low altitude.

SUMMARY

The findings emphasize the need for research in high-altitude communities to unravel the risks of pulmonary hypertension and pulmonary vascular diseases. Clinically, early and tailored management for symptomatic individuals residing at high altitudes are crucial, as well as access to advanced therapies as proposed by guidelines for pulmonary vascular disease. Moreover, identifying gaps in knowledge underscores the necessity for continued research to improve understanding and clinical outcomes in high-altitude pulmonary vascular diseases.

New Therapies in Outpatient Pulmonary Medicine

Newer medications and devices, as well as greater understanding of the benefits and limitations of existing treatments, have led to expanded treatment options for patients with lung disease. Treatment advances have led to improved outcomes for patients with asthma, chronic obstructive pulmonary disease, interstitial lung disease, pulmonary hypertension, and cystic fibrosis. The risks and benefits of available treatments are substantially variable within these heterogeneous disease groups. Defining the role of newer therapies mandates both an understanding of these disorders and overall treatment approaches. This section will review general treatment approaches in addition to focusing on newer therapies for these conditions..

Computational haemodynamics for pulmonary valve replacement by means of a reduced fluid-structure interaction model

Pulmonary valve replacement (PVR) consists of substituting a patient's original valve with a prosthetic one, primarily addressing pulmonary valve insufficiency, which is crucially relevant in Tetralogy of Fallot repairment. While extensive clinical and computational literature on aortic and mitral valve replacements is available, PVR's post-procedural haemodynamics in the pulmonary artery and the impact of prosthetic valve dynamics remain significantly understudied. Addressing this gap, we introduce a reduced Fluid-Structure Interaction (rFSI) model, applied for the first time to the pulmonary valve. This model couples a three-dimensional computational representation of pulmonary artery haemodynamics with a one-degree-of-freedom model to account for valve structural mechanics. Through this approach, we analyse patient-specific haemodynamics pre and post PVR. Patient-specific geometries, reconstructed from CT scans, are virtually equipped with a template valve geometry. Boundary conditions for the model are established using a lumped-parameter model, fine-tuned based on clinical patient data. Our model accurately reproduces patient-specific haemodynamic changes across different scenarios: pre-PVR, six months post-PVR, and a follow-up condition after a decade. It effectively demonstrates the impact of valve implantation on sustaining the diastolic pressure gradient across the valve. The numerical results indicate that our valve model is able to reproduce overall physiological and/or pathological conditions, as preliminary assessed on two different patients. This promising approach provides insights into post-PVR haemodynamics and prosthetic valve effects, shedding light on potential implications for patient-specific outcomes.

Group-Based Trajectory Modeling of N-Terminal Pro-Brain Natriuretic Peptide Levels in Pulmonary Artery Hypertension Associated with Connective Tissue Disease

Group-based trajectory modeling (GBTM) allows the trajectory analyses of repeated N-terminal pro-brain natriuretic peptide (NT-proBNP) measurements during follow-up visits of pulmonary artery hypertension associated with connective tissue disease (CTD-PAH) patients. This study aimed to (1) identify trajectories of NT-proBNP changing over time, (2) explore the association between NT-proBNP trajectories and prognosis, and (3) explore the effects of baseline clinical characteristics on NT-proBNP trajectories. A retrospective, single-centred, observational study was performed on 52 CTD-PAH patients who had undergone at least three follow-up visits within 1 year from baseline. Four NT-proBNP trajectories were identified using GBTM: low stability (n = 15, 28.85%), early remission (remission within 3 months) (n = 20, 38.46%), delayed remission (remission after 6 or 9 months) (n = 11, 21.15%), and high stability (n = 6, 11.54%). The low-stability and early-remission trajectories were related to a similar positive prognosis, while the delayed-remission and high-stability trajectories were associated with a gradually worsening prognosis (p = 0.000). Intensive CTD immunotherapy (corticosteroids plus immunosuppressants) was the only factor that remained significant after least absolute shrinkage and selection operator regression and multivariate logistic regression, and was independently associated with a lower risk NT-proBNP trajectory (p = 0.048, odds ratio = 0.027, 95% confidence interval: 0.001-0.963), which preliminarily indicated a benefit of CTD-PAH patients undergoing intensive CTD immunotherapy.

Physiological effects and safety of bed verticalization in patients with acute respiratory distress syndrome

BACKGROUND

Trunk inclination in patients with Acute Respiratory Distress Syndrome (ARDS) in the supine position has gained scientific interest due to its effects on respiratory physiology, including mechanics, oxygenation, ventilation distribution, and efficiency. Changing from flat supine to semi-recumbent increases driving pressure due to decreased respiratory system compliance. Positional adjustments also deteriorate ventilatory efficiency for CO2 removal, particularly in COVID-19-associated ARDS (C-ARDS), indicating likely lung parenchyma overdistension. Tilting the trunk reduces chest wall compliance and, to a lesser extent, lung compliance and transpulmonary driving pressure, with significant hemodynamic and gas exchange implications.

METHODS

A prospective, pilot physiological study was conducted on early ARDS patients in two ICUs at CHU Clermont-Ferrand, France. The protocol involved 30-min step gradual verticalization from a 30° semi-seated position (baseline) to different levels of inclination (0°, 30°, 60°, and 90°), before returning to the baseline position. Measurements included tidal volume, positive end-expiratory pressure (PEEP), esophageal pressures, and pulmonary artery catheter data. The primary endpoint was the variation in transpulmonary driving pressure through the verticalization procedure.

RESULTS

From May 2020 through January 2021, 30 patients were included. Transpulmonary driving pressure increased slightly from baseline (median and interquartile range [IQR], 9 [5-11] cmH2O) to the 90° position (10 [7-14] cmH2O; P < 10-2 for the overall effect of position in mixed model). End-expiratory lung volume increased with verticalization, in parallel to decreases in alveolar strain and increased arterial oxygenation. Verticalization was associated with decreased cardiac output and stroke volume, and increased norepinephrine doses and serum lactate levels, prompting interruption of the procedure in two patients. There were no other adverse events such as falls or equipment accidental removals.

CONCLUSIONS

Verticalization to 90° is feasible in ARDS patients, improving EELV and oxygenation up to 30°, likely due to alveolar recruitment and blood flow redistribution. However, there is a risk of overdistension and hemodynamic instability beyond 30°, necessitating individualized bed angles based on clinical situations. Trial registration ClinicalTrials.gov registration number NCT04371016 , April 24, 2020.

[Pulmonary hypertension in adults with congenital heart disease in light of the 2022-ESC-PAH guidelines - Part II: Supportive therapy, special situations (pregnancy, contraception, non-cardiac surgery), targeted pharmacotherapy, organ transplantation, special management (shunt lesions, left ventricular disorders, univentricular hearts), interventions, intensive care, follow-up, future perspectives]

The number of adults with congenital heart defects (CHD) is steadily rising and amounts to approximately 360,000 in Germany. CHD is often associated with pulmonary hypertension (PH), which may develop early in untreated CHD. Despite timely treatment of CHD, PH not infrequently persists or recurs in older age and is associated with significant morbidity and mortality.The revised European Society of Cardiology/European Respiratory Society 2022 guidelines for the diagnosis and treatment of PH represent a significant contribution to the optimized care of those affected. However, the topic of "adults with congenital heart disease" is addressed only relatively superficial in these guidelines. Therefore, in the present article, this topic is commented in detail from the perspective of congenital cardiology.

The Management of Mild Pulmonary Hypertension in Clinical Practice

The definition of pulmonary hypertension (PH) has been revised recently, with the mean pulmonary artery pressure (mPAP) threshold (assessed by right heart catheterization) reduced from ⩾25 mm Hg to >20 mm Hg. This change reflects the mPAP upper limit of normal and a lower limit that is independently associated with adverse outcomes. To improve the specificity of diagnosing pathogenic increases in mPAP, however, a diagnosis of precapillary PH now also includes pulmonary vascular resistance >2.0 Wood units (WU) (lowered from >3.0 WU). These changes are positioned to capture approximately 55% more patients with PH. Because all clinical trials showing a benefit of pulmonary vasodilator therapy in precapillary PH used the classical hemodynamic definition, the approach to the diagnosis and management of patients with mild PH (i.e., mPAP 21-24 mm Hg and pulmonary vascular resistance 2-3 WU) requires particular consideration. Here, we use a question/answer format to discuss key areas in the management of mild PH, including practical information tailored to clinicians without training in PH.

Pulmonary arterial wedge pressure in healthy subjects: a meta-analysis

Based on current international guidelines, pulmonary arterial wedge pressure (PAWP) is critical for differentiating between pre- and post-capillary pulmonary hypertension (PH) and plays an important role in the diagnosis of left heart failure [1, 2]. The current PAWP threshold to define post-capillary PH is >15 mmHg, measured by right heart catheterisation (RHC) in the supine position [1]. Historical data suggest that the upper limit of physiological PAWP may be lower [3–5], although no systematic review and meta-analysis has investigated the normal range of PAWP considering major confounding factors. We aimed to fill this knowledge gap by assessing the normal value of PAWP based on the largest available database of the published literature on pulmonary haemodynamics, also taking into account possible confounding factors, such as age, sex and RHC methodology.

Based on invasive haemodynamic measurements in healthy subjects, the upper limit of normal of PAWP in the supine resting position is 13 mmHg, which is dependent on sex, but independent of age and pressure reading https://bit.ly/3zer5cZ

Pulmonary Hypertension Associated with Connective Tissue Disease

Pulmonary hypertension (PH), a syndrome characterized by elevated pulmonary pressures, commonly complicates connective tissue disease (CTD) and is associated with increased morbidity and mortality. The incidence of PH varies widely between CTDs; patients with systemic sclerosis are most likely to develop PH. Several different types of PH can present in CTD, including PH related to left heart disease and respiratory disease. Importantly, CTD patients are at risk for developing pulmonary arterial hypertension, a rare form of PH that is associated with high morbidity and mortality. Future therapies targeting pulmonary vascular remodeling may improve outcomes for patients with this devastating disease.

Simulation-Informed Power Budget Estimate of a Fully-Implantable Brain-Computer Interface

This study aims to estimate the maximum power consumption that guarantees a thermally safe operation for a titanium-enclosed chest wall unit (CWU) subcutaneously implanted in the pre-pectoral area. This unit is a central piece of an envisioned fully-implantable bi-directional brain-computer interface (BD-BCI). To this end, we created a thermal simulation model using the finite element method implemented in COMSOL. We also performed a sensitivity analysis to ensure that our predictions were robust against the natural variation of physiological and environmental parameters. Based on this analysis, we predict that the CWU can consume between 378 and 538 mW of power without raising the surrounding tissue's temperature above the thermal safety threshold of 2 ∘ C. This power budget should be sufficient to power all of the CWU's basic functionalities, which include training the decoder, online decoding, wireless data transmission, and cortical stimulation. This power budget assessment provides an important specification for the design of a CWU-an integral part of a fully-implantable BD-BCI system.

Integrated modeling and simulation of recruitment of myocardial perfusion and oxygen delivery in exercise

While exercise-mediated vasoregulation in the myocardium is understood to be governed by autonomic, myogenic, and metabolic-mediated mechanisms, we do not yet understand the spatial heterogeneity of vasodilation or its effects on microvascular flow patterns and oxygen delivery. This study uses a simulation and modeling approach to explore the mechanisms underlying the recruitment of myocardial perfusion and oxygen delivery in exercise. The simulation approach integrates model components representing: whole-body cardiovascular hemodynamics, cardiac mechanics and myocardial work; myocardial perfusion; and myocardial oxygen transport. Integrating these systems together, model simulations reveal: (1.) To match expected flow and transmural flow ratios at increasing levels of exercise, a greater degree of vasodilation must occur in the subendocardium compared to the subepicardium. (2.) Oxygen extraction and venous oxygenation are predicted to substantially decrease with increasing exercise level preferentially in the subendocardium, suggesting that an oxygen-dependent error signal driving metabolic mediated recruitment of flow would be operative only in the subendocardium. (3.) Under baseline physiological conditions approximately 4% of the oxygen delivered to the subendocardium may be supplied via retrograde flow from coronary veins.

A spotlight on the aged pulmonary artery

The ever-increasing life expectancy of the global population introduces a critical perspective on the impact of aging as an immutable cardiovascular risk factor, particularly manifesting in the alterations observed in the pulmonary artery (PA). Mechanisms contributing to aging-induced changes in PA include endothelial dysfunction, chronic inflammation, and structural changes in the arterial wall over time. These alterations extend beyond mere elasticity, exerting profound effects on pulmonary hemodynamics. The propensity of PAs to develop atherosclerotic plaques underscores an intriguing facet of vascular aging, although the available literature is currently insufficient to comprehensively assess their true incidence. While recognizing the inherent risk of periprocedural complications, right heart catheterization (RHC) stands out as the gold standard for precise hemodynamic evaluation. Echocardiography, a widely employed method, proves valuable for screening pulmonary hypertension (PH), yet falls short of diagnostic capability. Technological advancements usher in a new era with non-invasive modalities such as cardiac magnetic resonance (CMR) imaging emerging as promising tools. These innovations demonstrate their prowess in providing accurate assessments of PA stiffness and hemodynamics, offering a glimpse into the future landscape of diagnostic methodologies. As we navigate the intersection of aging and pulmonary vascular health, this review aims to address mechanisms and techniques for assessing PA aging, highlighting the need for comprehensive assessments to guide clinical decision making in an increasingly aging population.

Derivation of Stroke Volume from Pulmonary Artery Pressures

INTRODUCTION

Intermittent cardiac output (CO) studies using thermodilution are considered the gold standard. We have developed a stroke volume (SV) calculator from pulmonary pulse pressure (PP) to allow continuous monitoring of SV and CO from PP.

METHODS

Hemodynamic data on 169 patients following orthotopic heart transplantation were used to compare our calculator-derived SV (and SV index, or SVi) against thermodilution-derived SV on admission into intensive care unit immediately following heart transplantation (T0) and 6 h after admission (T6).

RESULTS

The calculated SV correlated with thermodilution-derived SV T0 (r = 0.920, p < 0.001, coefficient of 0.539 and the constant of 2.06). The median calculator SV, adjusted for coefficient and constant, was 48.4 ml (37.7, 60.7), comparable to the median thermodilution-derived SV 47.9 ml (37.5, 61.0), p = 0.737 with acceptable agreement on Bland-Altman plots. The thermodilution-derived SVi was 28.1 ml (19.7, 38.7) and adjusted calculator-derived SVi 28.9 ml (19.7, 39.9), p = 0.781. At T6, median thermodilution-derived SVi was 27.7 ml (19.5, 35.9) compared to the calculator-derived SVi median of 26.1 ml (17.7, 37.7), p = 0.203.

CONCLUSIONS

Changes in PP can be used to track changes in SV using this calculator. Changes in PP may be used to assess response to treatment in the early post-operative period.

Recent developments in connective tissue disease associated pulmonary arterial hypertension

Connective tissue disease associated pulmonary arterial hypertension (CTD-PAH) has benefited from the major treatment advances that have occurred within pulmonary hypertension over the past three decades. Inclusion of CTD-PAH cases in pivotal clinical trials led to regulatory approval and drug availability. This has improved outcomes but there are additional challenges for management. First, the multifaceted co-morbidity related to the associated CTD needs treatment alongside PAH and may impact on diagnosis and evaluation of treatment response. Secondary, cardiac involvement, interstitial lung disease and predisposition to thromboembolism in CTD may lead to compound phenotypes where PH has multiple mechanisms as well as precapillary pulmonary vasculopathy of PAH. In general, especially for systemic sclerosis, CTD-PAH has worse long-term survival than idiopathic or familial PAH. However, CTD also present an opportunity for screening and early detection and treatment for associated PAH, and this may in the future be a major advantage over idiopathic disease where presentation inevitable only occurs at symptomatic stages and diagnosis may be delayed. This article reviews and summarises some of the recent developments in investigation and management of CTD-PAH.

The prognosis and management of reclassified systemic lupus erythematosus associated pulmonary arterial hypertension according to 2022 ESC/ERS guidelines

BACKGROUND AND AIMS

The 2022 European Society of Cardiology/European Respiratory Society (ESC/ERS) guideline has recently revised the hemodynamic definition of pulmonary arterial hypertension. However, there is currently limited research on the prognosis and treatment of system lupus erythematosus-associated pulmonary arterial hypertension (SLE-PAH) patients that have been reclassified by the new hemodynamic definition. This study aims to analyze the prognosis of newly reclassified SLE-PAH patients and provide recommendations for the management strategy.

METHODS

This retrospective study analyzed records of 236 SLE-PAH patients who visited Peking Union Medical College Hospital (PUMCH) from 2011 to 2023, among whom 22 patients were reclassified into mild SLE-PAH (mean pulmonary arterial pressure (mPAP) of 21-24 mmHg, pulmonary vascular resistance (PVR) of 2-3 WU, and PAWP ≤ 15 mmHg) according to the guidelines and 14 were defined as unclassified SLE-PAH patients (mPAP 21-24 mmHg and PVR ≤ 2 WU). The prognosis was compared among mild SLE-PAH, unclassified SLE-PH, and conventional SLE-PAH patients (mPAP ≥ 25 mmHg and PVR > 3WU). Besides, the effectiveness of pulmonary arterial hypertension (PAH)-specific therapy was evaluated in mild SLE-PAH patients.

RESULTS

Those mild SLE-PAH patients had significantly longer progression-free time than the conventional SLE-PAH patients. Among the mild SLE-PAH patients, 4 did not receive PAH-specific therapy and had a similar prognosis as patients not receiving specific therapy.

CONCLUSIONS

This study supports the revised hemodynamic definition of SLE-PAH in the 2022 ESC/ERS guideline. Those mild and unclassified SLE-PH patients had a better prognosis, demonstrating the possibility and significance of early diagnosis and intervention for SLE-PAH. This study also proposed a hypothesis that IIT against SLE might be sufficient for those reclassified SLE-PAH patients.