The right ventricle in pulmonary hypertension

Prognostic utility of exercise cardiovascular magnetic resonance in patients with systemic sclerosis-associated pulmonary arterial hypertension

AIMS

Systemic sclerosis complicated by pulmonary arterial hypertension (SSc-PAH) is a rare condition with poor prognosis. The majority of patients are categorized as intermediate risk of mortality. Cardiovascular magnetic resonance (CMR) is well placed to reproducibly assess right heart size and function, but most patients with SSc-PAH have less overtly abnormal right ventricles than other forms of PAH. The aim of this study was to assess if exercise CMR measures of cardiac size and function could better predict outcome in patients with intermediate risk SSc-PAH compared with resting CMR.

METHODS AND RESULTS

Fifty patients with SSc-PAH categorized as intermediate risk underwent CMR-augmented cardiopulmonary exercise testing. Most patients had normal CMR-defined resting measures of right ventricular (RV) size and function. Nine (18%) patients died during a median follow-up period of 2.1 years (range 0.1-4.6). Peak exercise RV indexed end-systolic volume (ESVi) was the only CMR metric to predict prognosis on stepwise Cox regression analysis, with an optimal threshold < 39 mL/m2 to predict favourable outcome. Intermediate-low risk patients with peak RVESVi < 39 mL/m2 had significantly better survival than all other combinations of intermediate-low/-high risk status and peak RVESVi< or ≥39 mL/m2. In our cohort, ventilatory efficiency and resting oxygen consumption (VO2) were predictive of mortality, but not peak VO2, peak cardiac output, or peak tissue oxygen extraction.

CONCLUSION

Exercise CMR assessment of RV size and function may help identify SSc-PAH patients with poorer prognosis amongst intermediate risk cohorts, even when resting CMR appears reassuring, and could offer added value to clinical PH risk stratification.

Native myocardial T1 and right ventricular size by CMR predict outcome in systemic sclerosis-associated pulmonary hypertension

OBJECTIVES

Measures of right heart size and function are prognostic in systemic sclerosis-associated pulmonary hypertension (SSc-PH), but the importance of myocardial tissue characterisation remains unclear. We aimed to investigate the predictive potential and interaction of cardiovascular magnetic resonance (CMR) myocardial tissue characterisation and right heart size and function in SSc-PH.

METHODS

A retrospective, single-centre, observational study of 148 SSc-PH patients confirmed by right heart catheterization who underwent clinically indicated CMR including native myocardial T1 and T2 mapping from 2016 to 2023 was performed.

RESULTS

Sixty-six (45%) patients died during follow-up (median 3.5 years, range 0.1-7.3). Patients who died were older (65 vs 60 years, P = 0.035) with more dilated (P < 0.001), hypertrophied (P = 0.013) and impaired (P < 0.001) right ventricles, more dilated right atria (P = 0.043) and higher native myocardial T1 (P < 0.001).After adjustment for age, indexed right ventricular end-systolic volume (RVESVi, P = 0.0023) and native T1 (P = 0.0024) were independent predictors of all-cause mortality. Both RVESVi and native T1 remained independently predictive after adjusting for age and PH subtype (RVESVi P < 0.001, T1 P = 0.0056). Optimal prognostic thresholds for RVESVi and native T1 were ≤38 mL/m2 and ≤1119 ms, respectively (P < 0.001). Patients with RVESVi ≤ 38 mL/m2 and native T1 ≤ 1119 ms had significantly better outcomes than all other combinations (P < 0.001). Furthermore, patients with RVESVi > 38mL/m2 and native T1 ≤ 1119 ms had significantly better survival than patients with RVESVi > 38mL/m2 and native T1 > 1119ms (P = 0.017).

CONCLUSION

We identified prognostically relevant CMR metrics and thresholds for patients with SSc-PH. Assessing myocardial tissue characterisation alongside right ventricular function confers added value in SSc-PH and may represent an additional treatment target.

Converging Pathways: A Review of Pulmonary Hypertension in Interstitial Lung Disease

Pulmonary hypertension (PH) in interstitial lung disease (ILD) is relatively common, affecting up to 50% of patients with idiopathic pulmonary fibrosis (IPF). It occurs more frequently in advanced fibrotic ILD, although it may also complicate milder disease and carries significant clinical implications in terms of morbidity and mortality. Key pathological processes driving ILD-PH include hypoxic pulmonary vasoconstriction and pulmonary vascular remodelling. While current understanding of the complex cell signalling pathways and molecular mechanisms underlying ILD-PH remains incomplete, there is evidence for an interplay between the disease pathogenesis of fibrotic ILD and PH, with interest in the role of the pulmonary endothelium in driving pulmonary fibrogenesis more recently. This review examines key clinical trials in ILD-PH therapeutics, including recent research showing promise for the treatment of both ILD-PH and the underlying pulmonary fibrotic process, further supporting the hypothesis of interrelated pathogenesis. Other important management considerations are discussed, including the value of accurate phenotyping in ILD-PH and the success of the "pulmonary vascular" phenotype. This article highlights the close and interconnected nature of fibrotic ILD and PH disease pathogenesis, a perspective likely to improve our understanding and therapeutic approach to this complex condition in the future.

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.

Atrial Arrhythmias in Patients With Pulmonary Hypertension

TOPIC IMPORTANCE

Atrial arrhythmias (AA) are common in patients with pulmonary hypertension (PH) and contribute to morbidity and mortality. Given the growing PH population, understanding the pathophysiology, clinical impact, and management of AA in PH is important.

REVIEW FINDINGS

AA occurs in PH with a 5-year incidence of 10% to 25%. AA confers a higher morbidity and mortality, and restoration of normal sinus rhythm improves survival and functionality. AA is thought to develop because of structural alterations of the right atrium caused by changes to the right ventricle (RV) due to elevated pulmonary artery pressures. AA can subsequently worsen RV function. Current guidelines do not provide comprehensive recommendations for the management of AA in PH. Robust evidence to favor a specific treatment approach is lacking. Although the role of medical rate or rhythm control, and the use of cardioversion and ablation, can be inferred from other populations, evidence is lacking in the PH population. Much remains to be determined regarding the optimal management strategy. We present here our institutional approach and discuss areas for future research.

SUMMARY

This review highlights the epidemiology and pathophysiology of AA in patients with PH, describes the relationship between AA and RV dysfunction, and discusses current management practices. We outline our institutional approach and offer directions for future investigation.

A computational study of right ventricular mechanics in a rat model of pulmonary arterial hypertension

Pulmonary arterial hypertension (PAH) presents a significant challenge to right ventricular (RV) function due to progressive pressure overload, necessitating adaptive remodeling in the form of increased wall thickness, enhanced myocardial contractility and stiffness to maintain cardiac performance. However, the impact of these remodeling mechanisms on RV mechanics in not clearly understood. In addition, there is a lack of quantitative understanding of how each mechanism individually influences RV mechanics. Utilizing experimental data from a rat model of PAH at three distinct time points, we developed biventricular finite element models to investigate how RV stress and strain evolved with PAH progression. The finite element models were fitted to hemodynamic and morphological data to represent different disease stages and used to analyze the impact of RV remodeling as well as the altered RV pressure. Furthermore, we performed a number of theoretical simulation studies with different combinations of morphological and physiological remodeling, to assess and quantify their individual impact on overall RV load and function. Our findings revealed a substantial 4-fold increase in RV stiffness and a transient 2-fold rise in contractility, which returned to baseline by week 12. These changes in RV material properties in addition to the 2-fold increase in wall thickness significantly mitigated the increase in wall stress and strain caused by the progressive increase in RV afterload. Despite the PAH-induced cases showing increased wall stress and strain at end-diastole and end-systole compared to the control, our simulations suggest that without the observed remodeling mechanisms, the increase in stress and strain would have been much more pronounced. Our model analysis also indicated that while changes in the RV's material properties-particularly increased RV stiffness - have a notable effect on its mechanics, the primary compensatory factor limiting the stress and strain increase in the early stages of PAH was the significant increase in wall thickness. These findings underscore the importance of RV remodeling in managing the mechanical burden on the right ventricle due to pressure overload.

Impact of pulmonary hypertension on short-term outcomes in patients undergoing surgical aortic valve replacement for severe aortic valve stenosis

OBJECTIVES

In patients with left heart disease and severe aortic stenosis (AS), pulmonary hypertension (PH) is a common comorbidity and predictor of poor prognosis. Untreated AS aggravates PH leading to an increased right ventricular afterload and, in line to right ventricular dysfunction. The surgical benefit of aortic valve replacement (AVR) in elderly patients with severe AS and PH could be limited due to the multiple comorbidities and poor outcomes. Therefore, we purposed to investigate the impact of PH on short-term outcomes in patients with moderate to severe AS who underwent surgical AVR in our heart center.

METHODS

In this study we retrospectively analyzed a cohort of 99 patients with severe secondary post-capillary PH who underwent surgical AVR (AVR + PH group) at our heart center between 2010 and 2021 with a regard to perioperative outcomes. In order to investigate the impact of PH on short-term outcomes, the control group of 99 patients without pulmonary hypertension who underwent surgical AVR (AVR group) at our heart center with similar risk profile was accordingly analyzed regarding pre-, intra- and postoperative data.

RESULTS

Atrial fibrillation occurred significantly more often (p = .013) in patients who suffered from PH undergoing AVR. In addition, the risk for cardiac surgery (EUROSCORE II) was significantly higher (p < .001) in the above-mentioned group. Likewise, cardiopulmonary bypass time (p = .018), aortic cross-clamp time (p = .008) and average operation time (p = .009) were significantly longer in the AVR + PH group. Furthermore, the in-hospital survival rate was significantly higher (p = .044) in the AVR group compared to the AVR + PH group. Moreover, the dialysis rate was significantly higher (p < .001) postoperatively in patients who suffered PH compared to the patients without PH undergoing AVR.

CONCLUSION

In our study, patients with severe PH and severe symptomatic AS who underwent surgical aortic valve replacement showed adverse short-term outcomes compared to patients without PH.

What echocardiographic findings differentiate acute pulmonary embolism and chronic pulmonary hypertension?

BACKGROUND

Pulmonary embolism (PE) and pulmonary hypertension (PH) are potentially fatal disease states. Early diagnosis and goal-directed management improve outcomes and survival. Both conditions share several echocardiographic findings of right ventricular dysfunction. This can inadvertently lead to incorrect diagnosis, inappropriate and potentially harmful management, and delay in time-sensitive therapies. Fortunately, bedside echocardiography imparts a few critical distinctions.

OBJECTIVE

This narrative review describes eight physiologically interdependent echocardiographic parameters that help distinguish acute PE and chronic PH. The manuscript details each finding along with associated pathophysiology and summarization of the literature evaluating diagnostic utility. This guide then provides pearls and pitfalls with high-quality media for the bedside evaluation.

DISCUSSION

The echocardiographic parameters suggesting acute or chronic right ventricular dysfunction (best used in combination) are: 1. Right heart thrombus (acute PE) 2. Right ventricular free wall thickness (acute ≤ 5 mm, chronic > 5 mm) 3. Tricuspid regurgitation pressure gradient (acute ≤ 46 mmHg, chronic > 46 mmHg, corresponding to tricuspid regurgitation maximal velocity ≤ 3.4 m/sec and > 3.4 m/sec, respectively) 4. Pulmonary artery acceleration time (acute ≤ 60-80 msec, chronic < 105 msec) 5. 60/60 sign (acute) 6. Pulmonary artery early-systolic notching (proximally-located, higher-risk PE) 7. McConnell's sign (acute) 8. Right atrial enlargement (equal to left atrial size suggests acute, greater than left atrial size suggests chronic).

CONCLUSIONS

Emergency physicians must appreciate the echocardiographic findings and associated pathophysiology that help distinguish acute and chronic right ventricular dysfunction. In the proper clinical context, these findings can point towards PE or PH, thereby leading to earlier goal-directed management.

Right Ventricular Systolic Pressure Trajectory as a Predictor of Hospitalization and Mortality in Patients With Chronic Heart Failure

Background

Pulmonary hypertension is common among patients with heart failure (HF). Right ventricular systolic pressure (RVSP) is frequently used to assess its presence and severity. Although RVSP has been associated with adverse outcomes, the importance of serial measurements has not been studied. We evaluated associations between serial RVSP measurements and cardiovascular events in patients with HF.

Methods

Patients with HF and 2 echocardiograms performed ≥ 6 months apart were included. RVSP was categorized, using the second echocardiogram, as follows: normal (< 40 mm Hg); severely elevated (≥ 60 mm Hg); moderately elevated (50-59 mm Hg); or mildly elevated (40-49 mm Hg). Patients also were classified according to change in RVSP categories between echocardiograms. The primary outcome was time to HF hospitalization (HFH) or all-cause mortality (ACM) after the second echocardiogram.

Results

In total, 4319 patients were included (median age: 78 years; 52.1% female). During a median follow-up period of 19.4 months, HFH/ACM occurred in 2714 patients (62.8%). In multivariable analysis, baseline RSVP that was mildly elevated (1069 patients, hazard ratio [HR] 1.31, 95% confidence interval [CI] 1.12-1.54), moderately elevated (797 patients, HR 1.54, 95% CI 1.30-1.82), or severely elevated (837 patients, HR 1.92, 95% CI 1.60-2.31) was independently associated with HFH/ACM. Additionally, improving RVSP was associated with increased HFH/ACM in both categorical (HR 1.16, 95% CI 1.01-1.33) and continuous analyses.

Conclusions

RVSP measurements identify patients at increased risk who may require more-aggressive monitoring and medical therapy. Our study raises the hypothesis that, in addition to the absolute value of RVSP, improving RVSP category may identify higher-risk patients, but further study is needed to elucidate the underlying reasons.

Pathophysiology and pathogenic mechanisms of pulmonary hypertension: role of membrane receptors, ion channels, and Ca2+ signaling

The pulmonary circulation is a low-resistance, low-pressure, and high-compliance system that allows the lungs to receive the entire cardiac output. Pulmonary arterial pressure is a function of cardiac output and pulmonary vascular resistance, and pulmonary vascular resistance is inversely proportional to the fourth power of the intraluminal radius of the pulmonary artery. Therefore, a very small decrease of the pulmonary vascular lumen diameter results in a significant increase in pulmonary vascular resistance and pulmonary arterial pressure. Pulmonary arterial hypertension is a fatal and progressive disease with poor prognosis. Regardless of the initial pathogenic triggers, sustained pulmonary vasoconstriction, concentric vascular remodeling, occlusive intimal lesions, in situ thrombosis, and vascular wall stiffening are the major and direct causes for elevated pulmonary vascular resistance in patients with pulmonary arterial hypertension and other forms of precapillary pulmonary hypertension. In this review, we aim to discuss the basic principles and physiological mechanisms involved in the regulation of lung vascular hemodynamics and pulmonary vascular function, the changes in the pulmonary vasculature that contribute to the increased vascular resistance and arterial pressure, and the pathogenic mechanisms involved in the development and progression of pulmonary hypertension. We focus on reviewing the pathogenic roles of membrane receptors, ion channels, and intracellular Ca2+ signaling in pulmonary vascular smooth muscle cells in the development and progression of pulmonary hypertension.

Right ventricular dysfunction in patients with acute respiratory distress syndrome receiving venovenous extracorporeal membrane oxygenation

Acute respiratory distress syndrome is characterized by non-cardiogenic pulmonary edema, decreased pulmonary compliance, and abnormalities in gas exchange, especially hypoxemia. Patients with acute respiratory distress syndrome (ARDS) who receive support with venovenous (V-V) extracorporeal membrane oxygenation (ECMO) usually have severe lung disease. Many patients with ARDS have associated pulmonary vascular injury which can result in elevated pulmonary vascular resistance and right heart dysfunction. Since V-V ECMO relies upon preserved cardiac function, right heart failure has important implications for patient evaluation, management, and outcomes. Worsening right heart function complicates ARDS and disease processes. Given the increasing use of ECMO to support patients with ARDS, an understanding of right ventricular-ECMO and cardiopulmonary interactions is essential for the clinician. A narrative review of the manifestations of right heart dysfunction, as well as diagnosis and management strategies for the patient with ARDS on ECMO, is provided.

Right Ventricular Limitation: A Tale of Two Elastances

Right ventricular (RV) dysfunction is a commonly considered cause of low cardiac output in critically ill patients. Its management can be difficult and requires an understanding of how the RV limits cardiac output. We explain that RV stroke output is caught between the passive elastance of the RV walls during diastolic filling and the active elastance produced by the RV in systole. These two elastances limit RV filling and stroke volume and consequently limit left ventricular stroke volume. We emphasize the use of the term "RV limitation" and argue that limitation of RV filling is the primary pathophysiological process by which the RV causes hemodynamic instability. Importantly, RV limitation can be present even when RV function is normal. We use the term "RV dysfunction" to indicate that RV end-systolic elastance is depressed or diastolic elastance is increased. When RV dysfunction is present, RV limitation occurs at lowerpulmonary valve opening pressures and lower stroke volume, but stroke volume and cardiac output still can be maintained until RV filling is limited. We use the term "RV failure" to indicate the condition in which RV output is insufficient for tissue needs. We discuss the physiological underpinnings of these terms and implications for clinical management.

The myocardial capillary network is altered in congenital diaphragmatic hernia in the fetal rabbit model

Congenital diaphragmatic hernia (CDH) is associated with thoracic compression of the lungs and heart caused by the herniated abdominal content, leading to cardiac modifications including pressure and vascular changes. Our aim was to investigate the experimental immunoexpression of the capillary proliferation, activation, and density of Ki-67, VEGFR2, and lectin in the myocardium after surgical creation of a diaphragmatic defect. Pregnant New Zealand rabbits were operated on the 25th gestational day in order to create left-sided CDH (LCDH, n=9), right-sided CDH (RCDH, n=9), and Control (n=9), for a total of 27 fetuses in 19 pregnant rabbits. Five days after the procedure, animals were sacrificed, and histology and immunohistochemistry studies of the harvested hearts were performed. Total body weight and heart weight were not significantly different among groups (P=0.702 and 0.165, respectively). VEGFR2 expression was increased in both ventricles in the RCDH group (P<0.0001), and Ki-67 immunoexpression was increased in the left ventricle in the LCDH group compared to Control and RCDH groups (P<0.0001). In contrast, capillary density was reduced in the left ventricle in the LCDH compared to the Control and RCDH groups (P=0.002). Left and right ventricles responded differently to CDH in this model depending on the laterality of the diaphragmatic defect. This surgical model of diaphragmatic hernia was associated with different expression patterns of capillary proliferation, activation, and density in the myocardium of the ventricles of newborn rabbits.

Bedside Ultrasound for Hemodynamic Monitoring in Cardiac Intensive Care Unit

Thanks to the advances in medical therapy and assist devices, the management of patients hospitalized in cardiac intensive care unit (CICU) is becoming increasingly challenging. In fact, Patients in the cardiac intensive care unit are frequently characterized by dynamic and variable diseases, which may evolve into several clinical phenotypes based on underlying etiology and its complexity. Therefore, the use of noninvasive tools in order to provide a personalized approach to these patients, according to their phenotype, may help to optimize the therapeutic strategies towards the underlying etiology. Echocardiography is the most reliable and feasible bedside method to assess cardiac function repeatedly, assisting clinicians not only in characterizing hemodynamic disorders, but also in helping to guide interventions and monitor response to therapies. Beyond basic echocardiographic parameters, its application has been expanded with the introduction of new tools such as lung ultrasound (LUS), the Venous Excess UltraSound (VexUS) grading system, and the assessment of pulmonary hypertension, which is fundamental to guide oxygen therapy. The aim of this review is to provide an overview on the current knowledge about the pathophysiology and echocardiographic evaluation of perfusion and congestion in patients in CICU, and to provide practical indications for the use of echocardiography across clinical phenotypes and new applications in CICU.

A new machine learning model for predicting severity prognosis in patients with pulmonary embolism: Study protocol from Wenzhou, China

Introduction

Pulmonary embolism (PE) is a common thrombotic disease and potentially deadly cardiovascular disorder. The ratio of clinical misdiagnosis and missed diagnosis of PE is very large because patients with PE are asymptomatic or non-specific.

Methods

Using the clinical data from the First Affiliated Hospital of Wenzhou Medical University (Wenzhou, China), we proposed a swarm intelligence algorithm-based kernel extreme learning machine model (SSACS-KELM) to recognize and discriminate the severity of the PE by patient's basic information and serum biomarkers. First, an enhanced method (SSACS) is presented by combining the salp swarm algorithm (SSA) with the cuckoo search (CS). Then, the SSACS algorithm is introduced into the KELM classifier to propose the SSACS-KELM model to improve the accuracy and stability of the traditional classifier.

Results

In the experiments, the benchmark optimization performance of SSACS is confirmed by comparing SSACS with five original classical methods and five high-performance improved algorithms through benchmark function experiments. Then, the overall adaptability and accuracy of the SSACS-KELM model are tested using eight public data sets. Further, to highlight the superiority of SSACS-KELM on PE datasets, this paper conducts comparison experiments with other classical classifiers, swarm intelligence algorithms, and feature selection approaches.

Discussion

The experimental results show that high D-dimer concentration, hypoalbuminemia, and other indicators are important for the diagnosis of PE. The classification results showed that the accuracy of the prediction model was 99.33%. It is expected to be a new and accurate method to distinguish the severity of PE.

Exercise training decreases oxidative stress in skeletal muscle of rats with pulmonary arterial hypertension

The effects of exercise training on oxidative stress in gastrocnemius of rats with pulmonary hypertension were studied. Four groups were established: sedentary control (SC), sedentary monocrotaline (SM), trained control (TC), trained monocrotaline (TM). Exercise was applied for 4 weeks, 5 days/week, 50-60 min/session, at 60% of VO₂ max. Right ventricular (RV) pressures were measured, heart and gastrocnemius were removed for morphometric/biochemical analysis. Lipid peroxidation (LPO), H₂O₂, GSH/GSSG, and activity/expression of antioxidant enzymes were evaluated. Increased RV hypertrophy, systolic and end-diastolic pressures (RVEDP) were observed in SM animals, and the RVEDP was decreased in TM vs. SM. H₂O₂, SOD-1, and LPO were higher in the SM group than in SC. In TM, H₂O₂ was further increased when compared to SM, with a rise in antioxidant defences and a decrease in LPO. GSH/GSSG was higher only in the TC group. Exercise induced an efficient antioxidant adaptation, preventing oxidative damage to lipids.

The Balance between the Left and Right Ventricular Deformation Evaluated by Speckle Tracking Echocardiography Is a Great Predictor of the Major Adverse Cardiac Event in Patients with Pulmonary Hypertension

Cardiovascular failure is one of the most relevant causes of death in pulmonary hypertension (PH). With progressive increases of right ventricular (RV) afterload in PH patients, both RV and left ventricular (LV) function impair and RV–LV dyssynchrony develop in parallel. We aimed to analyze the balance between the left and right ventricular deformation to assess the outcome of patients with pulmonary hypertension by means of speckle tracking echocardiography. In this prospective study, 54 patients with invasively diagnosed pulmonary hypertension, and 26 healthy volunteers were included and underwent a broad panel of noninvasive assessment including 2D-echocardiography, 2D speckle tracking, 6-minute walking test and BNP. Patients were followed up for 338.7 ± 131.1 (range 60 to 572) days. There were significant differences in |LVGLS/RVFLS-1| and |LASc/RASc-1| between PH patients and the control group. During the follow up, 13 patients experienced MACEs, which included 7 patients with cardiac death and 6 patients with re-admitted hospital due to right ventricular dysfunction. In the multivariate Cox model analysis, |LVGLS/RVFLS-1| remained independent prognosis of markers (HR = 4.03). Our study findings show that |LVGLS/RVFLS-1| is of high clinical and prognostic relevance in pulmonary hypertension patients and reveal the importance of the balance between the left and right ventricular deformation.

Prehospital Ultrasound Diagnosis of Massive Pulmonary Embolism by Non-Physicians: A Case Series

Massive pulmonary embolism (hemodynamically unstable, defined as systolic BP <90 mmHg) has significant morbidity and mortality. Point of care ultrasound (POCUS) has allowed clinicians to detect evidence of massive pulmonary embolism much earlier in the patient's clinical course, especially when patient instability precludes computerized tomography confirmation. POCUS detection of massive pulmonary embolism has traditionally been performed by physicians. This case series demonstrates four cases of massive pulmonary embolism diagnosed with POCUS performed by non-physician prehospital personnel.

Computational models of ventricular mechanics and adaptation in response to right-ventricular pressure overload

Pulmonary arterial hypertension (PAH) is associated with substantial remodeling of the right ventricle (RV), which may at first be compensatory but at a later stage becomes detrimental to RV function and patient survival. Unlike the left ventricle (LV), the RV remains understudied, and with its thin-walled crescent shape, it is often modeled simply as an appendage of the LV. Furthermore, PAH diagnosis is challenging because it often leaves the LV and systemic circulation largely unaffected. Several treatment strategies such as atrial septostomy, right ventricular assist devices (RVADs) or RV resynchronization therapy have been shown to improve RV function and the quality of life in patients with PAH. However, evidence of their long-term efficacy is limited and lung transplantation is still the most effective and curative treatment option. As such, the clinical need for improved diagnosis and treatment of PAH drives a strong need for increased understanding of drivers and mechanisms of RV growth and remodeling (G&R), and more generally for targeted research into RV mechanics pathology. Computational models stand out as a valuable supplement to experimental research, offering detailed analysis of the drivers and consequences of G&R, as well as a virtual test bench for exploring and refining hypotheses of growth mechanisms. In this review we summarize the current efforts towards understanding RV G&R processes using computational approaches such as reduced-order models, three dimensional (3D) finite element (FE) models, and G&R models. In addition to an overview of the relevant literature of RV computational models, we discuss how the models have contributed to increased scientific understanding and to potential clinical treatment of PAH patients.

Diagnosis & management of pulmonary hypertension in congenital diaphragmatic hernia

Congenital diaphragmatic hernia (CDH) contributes to neonatal morbidity and mortality worldwide. Pulmonary hypertension (PH) is a key component of CDH pathophysiology and critical consideration for management and therapeutic options. PH associated with CDH has traditionally been attributed to pulmonary vascular maldevelopment and associated lung parenchymal hypoplasia, leading to pre-capillary increase in pulmonary vascular resistance (PVR). However, there is increasing recognition that left ventricular hypoplasia, dysfunction and elevated end diastolic pressure may contribute to post-capillary pulmonary hypertension in CDH patients. The interplay of these mechanisms and associated dysfunction in the right and left ventricles results in variable hemodynamic phenotypes in CDH. Clinical assessment of individual phenotype may help guide personalized management strategies, including effective use of pulmonary vasodilators and extra-corporeal membrane oxygenation. Ongoing investigation of the underlying mechanisms of PH in CDH, and efficacy of physiology-based treatment approaches may support improvement in outcomes in this challenging condition.

Right heart strain assessment on CTPA following acute pulmonary embolism: Interobserver variability between expert radiologists and physicians

BACKGROUND

Accuracy of right heart strain (RHS) measured on computed tomography pulmonary angiogram (CTPA) scans by non-radiologists is unknown. We assessed inter-observer variability of four RHS features and determined the accuracy of measurements by respiratory physicians.

METHOD

1560 consecutive patients with acute PE were identified, and those who had a CTPA and an echocardiogram within 24-h included. CTPAs were independently scored prospectively by two radiologists, two thoracic physicians and a specialist registrar. Inter-observer variability was assessed, and diagnostic accuracy compared to echocardiography.

RESULTS

182 patients (median age 62.8 years, IQR 49.8-71.5) with acute PE (7.7% high-risk, 40.7% intermediate high-risk, 31.3% intermediate low-risk and 20.3% low-risk) were included. Right ventricle to left ventricle diameter ratio (RV:LV) measurement had low inter-observer variability among the radiologists and non-radiologists with interclass correlation coefficient (ICC) of 0.95 (95%CI 0.92-0.97) and 0.96 (95%CI 0.94-0.97) respectively. RV:LV ratio had high diagnostic accuracy compared to RV dilatation on echocardiography (AUC 0.89, 95%CI 0.84-0.94 for radiologists and AUC 0.84, 95%CI 0.77-0.90 for non-radiologists). Main pulmonary artery to ascending aorta diameter ratio (MPA:Ao) measurement also had excellent agreement amongst the radiologists and non-radiologists (ICC 0.93 (95%CI 0.88-0.96) and 0.92 (95%CI 0.81-0.96) respectively). Significant variability was seen in the assessment of subjective features of RHS (leftward bowing of interventricular septum and contrast reflux into inferior vena cava) amongst the non-radiologists.

CONCLUSION

RV:LV and MPA:Ao diameter ratios on CTPA measured by non-radiologists have low inter-observer variability and good agreement with radiologists, and can be reliably used where an expert report is unavailable.

Right Ventricular Shape Feature Quantification for Evaluation of Pulmonary Hypertension: Feasibility and Preliminary Associations With Clinical Outcome Submitted for Publication

This study aimed to demonstrate feasibility of statistical shape analysis techniques to identify distinguishing features of right ventricle (RV) shape as related to hemodynamic variables and outcome data in pulmonary hypertension (PH). Cardiovascular magnetic resonance images were acquired from 50 patients (33 PH, 17 non-PH). Contemporaneous right heart catheterization data were collected for all individuals. Outcome was defined by all-cause mortality and hospitalization for heart failure. RV endocardial borders were manually segmented, and three-dimensional surfaces reconstructed at end diastole and end systole. Registration and harmonic mapping were then used to create a quantitative correspondence between all RV surfaces. Proper orthogonal decomposition was performed to generate modes describing RV shape features. The first 15 modes captured over 98% of the total modal energy. Two shape modes, 8 (free wall expansion) and 13 (septal flattening), stood out as relating to PH state (mode 13: r = 0.424, p = 0.002; mode 8: r = 0.429, p = 0.002). Mode 13 was significantly correlated with outcome (r = 0.438, p = 0.001), more so than any hemodynamic variable. Shape analysis techniques can derive unique RV shape descriptors corresponding to specific, anatomically meaningful features. The modes quantify shape features that had been previously only qualitatively related to PH progression. Modes describing relevant RV features are shown to correlate with clinical measures of RV status, as well as outcomes. These new shape descriptors lay the groundwork for a noninvasive strategy for identification of failing RVs, beyond what is currently available to clinicians.

IL-33/ST2 receptor-dependent signaling in the development of pulmonary hypertension in Sugen/hypoxia mice

Pulmonary arterial hypertension (PAH) is associated with significant morbidity and mortality. PAH is characterized by pulmonary artery remodeling, elevated right ventricular pressure (RVP) and, ultimately, cardiac failure. Pulmonary endothelial cells can sense danger or damage caused by mechanical injury or pathogens through alarmin cytokines. These cytokines can signal proliferation to restore barrier integrity or aberrant hyperproliferation and remodeling. We hypothesized that IL‐33 signals pulmonary artery endothelial cells to proliferate under hypertensive conditions during the remodeling response and rise in RVP. To test this hypothesis, pulmonary hypertension (PH) was induced in C57Bl/6J, IL‐33 receptor gene deleted (ST2^−/−) and MYD88 gene deleted (MYD88^−/−) mice by exposure to 10% O₂ and SU5416 injections (SUHX). RVP, arterial wall thickness, endothelial cell proliferation and IL‐33 levels and signaling were evaluated. In response to SUHX. RVP increased in C57Bl/6J mice in response to SUHX (49% male and 70% female; p < 0.0001) and this SUHX response was attenuated in ST2^−/− mice (29% male p = 0.003; 30% female p = 0.001) and absent in MYD88^−/− mice. Wall thickness was increased in SUHX C57Bl/6J mice (p = 0.005), but not in ST2^−/− or MYD88^−/− mice. Proliferating cells were detected in C57Bl/6J mice by flow cytometry (CD31⁺/BrDU⁺; p = 0.02) and immunofluorescence methods (Ki‐67+). IL‐33 was increased by SUHX (p = 0.03) but a genotype effect was not observed (p = 0.76). We observed that in hPAECs, IL‐33 expression is regulated by both IL‐33 and DLL4. These data suggest IL‐33/ST2 signaling is essential for the endothelial cell proliferative response in PH.

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.

Serious illness conversations in pulmonary hypertension

Pulmonary arterial hypertension has evolved from a fatal disease with few treatment options to a chronic condition with improved survival. This improvement is possible through development of effective therapies as well as the expansion of risk stratification scores to assist clinical decision making. Despite improved disease control, quality of life, and overall prognosis, many challenges remain. The treatment itself is burdensome, with significant impact on quality of life. Many patients with pulmonary arterial hypertension still present with advanced, often end-stage disease. Increased use of mechanical circulatory support and catheter-based interventions have expanded use of extracorporeal life support and right ventricle assist devices. For these reasons as well as the long-term relationships pulmonary hypertension physicians have with patients and their families, navigating the course of the illness in a considered, proactive way is essential. Understanding individual goals and revisiting them as they change over time requires comfort with the conversation itself. There are many barriers and challenges to having effective, compassionate conversations in the clinical setting with time constraints being the most often cited. Compressed visits are necessarily focused on the clinical aspects, therapy and medication adherence and tolerance. Clinicians are sometimes wary of diminishing hope in the face of ongoing treatment. Having sufficient experience and comfort with these discussions can be empowering. In this paper, we discuss the challenges involved and propose a framework to assist in incorporating these discussions into clinical care.

Non-Invasive Risk Prediction Based on Right Ventricular Function in Patients with Pulmonary Arterial Hypertension

BACKGROUND

Right ventricular dysfunction is a major determinant of outcome in pulmonary arterial hypertension (PAH). We aimed to identify echocardiographic right heart parameters associated with adverse outcome and to develop a non-invasive, echocardiography-based risk score for PAH patients.

METHODS AND RESULTS

In 254 PAH patients we analyzed functional status, laboratory results, and echocardiographic parameters. We included these parameters to estimate all-cause death or lung transplantation using Cox regression models. The analyses included a conventional model using guideline-recommended variables and an extended echocardiographic model. Based on the final model a 12-point risk score was derived, indicating the association with the primary outcome within five years. During a median follow-up time of 4.2 years 74 patients died or underwent lung transplantation. The conventional model resulted in a C-Index of 0.539, whereas the extended echocardiographic model improved the discrimination (C-index 0.639, p-value 0.017). Ultimately, the newly developed risk score included WHO functional class, 6-min walking distance, N-terminal brain natriuretic peptide concentrations, pericardial effusion, right atrial area, tricuspid annular plane systolic excursion, and fractional area change.

CONCLUSION

Integrating right heart function assessed by echocardiography improves prediction of death or lung transplantation in PAH patients. Independent validation of this finding is warranted.

Treatment of adults with Eisenmenger syndrome-state of the art in the 21st century: a short overview

Eisenmenger syndrome (ES) develops in association with unrepaired, non-restrictive cardiac shunt lesions at the atrial, ventricular or arterial level over time. In developed countries, cardiac defects are being operated on in a timely manner, before pulmonary vascular disease develops. However, with rising immigration from underserved countries, we increasingly see patients with shunt lesions, that are not amenable for repair as pulmonary vascular disease has already established. ES describes a symptom complex and patients present with heterogeneous problems involving many organ systems (multisystem disorder). Care in tertiary specialist cardiac centers with access to multidisciplinary subspecialities is required. Central cyanosis with secondary erythrocytosis is one of the key features of patients with ES. Clinical consequences of longstanding hypoxia can lead to other organ complications, that involve other organs than the heart alone. Although ES patients have a better prognosis compared to other patients with pulmonary arterial hypertension, ES grossly affects quality of life and morbidity is frequent. Follow-up and care at specialist congenital heart disease centers is highly recommended to prevent, to early diagnose and to timely manage complications of ES. This is necessary to maintain functional capacity, decrease morbidity and increase life expectancy for these vulnerable patients. The leading reasons for mortality are sudden cardiac death, progressive heart failure, and infectious diseases. Various factors have been shown to be associated with mortality like decreased arterial oxygen saturation, functional class, impaired exercise tolerance, syncopal events, iron deficiency, presence of pre-tricuspid shunts, arrhythmias, increased (NT-pro) brain natriuretic peptide, echocardiographic variables of right ventricular dysfunction and hospitalization for heart failure. Although to date there is no causal therapy to reverse pulmonary vascular disease, a greater armamentarium of targeted therapies is available, which have been shown to be beneficial in patients with ES.

Exploring Functional Differences between the Right and Left Ventricles to Better Understand Right Ventricular Dysfunction

The right and left ventricles have traditionally been studied as individual entities. Furthermore, modifications found in diseased left ventricles are assumed to influence on right ventricle alterations, but the connection is poorly understood. In this review, we describe the differences between ventricles under physiological and pathological conditions. Understanding the mechanisms that differentiate both ventricles would facilitate a more effective use of therapeutics and broaden our knowledge of right ventricle (RV) dysfunction. RV failure is the strongest predictor of mortality in pulmonary arterial hypertension, but at present, there are no definitive therapies directly targeting RV failure. We further explore the current state of drugs and molecules that improve RV failure in experimental therapeutics and clinical trials to treat pulmonary arterial hypertension and provide evidence of their potential benefits in heart failure.

Basement Membrane Extracellular Matrix Proteins in Pulmonary Vascular and Right Ventricular Remodeling in Pulmonary Hypertension

The extracellular matrix (ECM), a highly organized network of structural and nonstructural proteins, plays a pivotal role in cellular and tissue homeostasis. Changes in the ECM are critical for normal tissue repair, whereas dysregulation contributes to aberrant tissue remodeling. Pulmonary arterial hypertension is a severe disorder of the pulmonary vasculature characterized by pathologic remodeling of the pulmonary vasculature and right ventricle, increased production and deposition of structural and nonstructural proteins, and altered expression of ECM growth factors and proteases. Furthermore, ECM remodeling plays a significant role in disease progression, as several dynamic changes in its composition, quantity, and organization are documented in both humans and animal models of disease. These ECM changes impact vascular cell biology and affect proliferation of resident cells. Furthermore, ECM components determine the tissue architecture of the pulmonary and myocardial vasculature as well as the myocardium itself and provide mechanical stability crucial for tissue homeostasis. However, little is known about the basement membrane (BM), a specialized, self-assembled conglomerate of ECM proteins, during remodeling. In the vasculature, the BM is in close physical association with the vascular endothelium and smooth muscle cells. While in the myocardium, each cardiomyocyte is enclosed by a BM that serves as the interface between cardiomyocytes and the surrounding interstitial matrix. In this review, we provide a brief overview on the current state of knowledge of the BM and its ECM composition and their impact on pulmonary vascular remodeling and right ventricle dysfunction and failure in pulmonary arterial hypertension.

Risk assessment in interstitial lung disease: the incremental prognostic value of cardiopulmonary ultrasound

Background

The mortality risk of chronic interstitial lung disease (ILD) is currently assessed using the ILD-GAP score. The present study evaluates whether the addition of cardiopulmonary ultrasound parameters to the ILD-GAP score can further improve the predictive value of ILD-GAP.

Methods

Medical records from 91 patients with ILD hospitalized from June 2015 to March 2016 were retrospectively examined. The Lung ultrasound (LUS) score, right ventricular (RV) function, and mechanics were obtained from the cardiopulmonary ultrasound. The ILD-GAP score was calculated from demographic characteristics and pulmonary function parameters. Patients were followed up with until May 2020. The primary endpoint was all-cause death.

Results

After exclusions, 74 patients with ILD were included in the analysis. During the follow-up period, 36 patients with ILD survived (ILD_s), and 38 patients died (ILD_d). Compared to ILD_s, the ILD_d cases exhibited a higher number of B-lines, LUS score, and RV end-diastolic base dimension (RVD), but lower RV function. In multivariate analysis, the ILD-GAP score (hazard ratio, 2.88; 95% CI 1.38–5.99, P = 0.005), LUS score (hazard ratio 1.13; 95% CI 1.04–1.24, P = 0.006), and RVD (hazard ratio 1.09, 95% CI 1.03–1.16, P = 0.004) were significantly related to the risk of death. Adding the LUS score and RVD to the ILD-GAP score significantly improved the predictive value compared to the ILD-GAP score alone (C statistics 0.90 vs 0.76, P = 0.018).

Conclusion

We investigated the utility of a new prognostic model for ILD that includes both cardiopulmonary ultrasound parameters (LUS score and RVD) and the ILD-GAP score. This model better reflects the severity of pulmonary fibrosis and cardiac involvement, and has incremental predictive value over the ILD-GAP score alone.

Changes in the Pulmonary Artery Wave Reflection in Dogs with Experimentally-Induced Acute Pulmonary Embolism and the Effect of Vasodilator

Simple Summary

Pulmonary hypertension (PH) remains a fatal disease, despite the advances in disease-specific therapies. This may be because the assessment of pulmonary hemodynamics in PH has not been established. Recently, several studies have reported that the pulmonary arterial wave reflection (PAWR) might influence the right ventricular afterload and could provide additional information regarding the severity and progression of PH. However, the pathophysiology of PAWR has some unclear points particularly in the case of acute pulmonary embolism (APE). The objective of this study was to investigate, for the first time, the characteristics of PAWR in a dog model of APE using dual-tipped sensor wire. From the result of the present study, after dogs developed PH by injections of dextran microsphere, PAWR was increased significantly along with the pulmonary vascular resistance (PVR) and reduced after vasodilator administration. In addition, PAWR was significantly correlated with PVR and right ventricular fractional area of change (FAC). These results indicating that PAWR may be useful as a new evaluation method in PH and may detect changes related to right ventricular afterload earlier than pulmonary artery pressure (PAP).

Abstract

Pulmonary hypertension (PH) is a complex syndrome that has been frequently diagnosed in dogs and humans and can be detected by Doppler echocardiography and invasive catheterization. Recently, PAWR attracts much attention as a noninvasive approach for the early detection of PH. The present study aims to investigate the PAWR changes in acute pulmonary embolism (APE) and highlight the response of PAWR variables to vasodilator therapy in dogs. For this purpose, anesthesia and catheterization were performed in 6 Beagle dogs. After that, APE was experimentally conducted by Dextran microsphere administration, followed by vasodilator (Nitroprusside; 1μg/kg/min/IV) administration. The hemodynamics, echocardiography, PVR and PAWR variables were evaluated at the baseline, after APE and after administration of nitroprusside. The result showed a significant increase in PVR, PAP, tricuspid regurgitation (TR) as well as PAWR variables following APE induction compared with the baseline (p < 0.05). Vasodilation caused by administration of nitroprusside reduced the mean atrial pressure, PVR and PAWR parameters. There were a significant correlation and linear regression between PAWR indices and PVR as well as right ventricular function parameters. In conclusion, PAWR is not only correlated with PVR but also the right ventricular function parameter, which indicates that PAWR may be useful as a new evaluation method in PH, considering that PAWR can assess both right ventricular afterload and right ventricular function.

Management of Congenital Diaphragmatic Hernia (CDH): Role of Molecular Genetics

Congenital diaphragmatic hernia (CDH) is a relatively common major life-threatening birth defect that results in significant mortality and morbidity depending primarily on lung hypoplasia, persistent pulmonary hypertension, and cardiac dysfunction. Despite its clinical relevance, CDH multifactorial etiology is still not completely understood. We reviewed current knowledge on normal diaphragm development and summarized genetic mutations and related pathways as well as cellular mechanisms involved in CDH. Our literature analysis showed that the discovery of harmful de novo variants in the fetus could constitute an important tool for the medical team during pregnancy, counselling, and childbirth. A better insight into the mechanisms regulating diaphragm development and genetic causes leading to CDH appeared essential to the development of new therapeutic strategies and evidence-based genetic counselling to parents. Integrated sequencing, development, and bioinformatics strategies could direct future functional studies on CDH; could be applied to cohorts and consortia for CDH and other birth defects; and could pave the way for potential therapies by providing molecular targets for drug discovery.

The left ventricle undergoes biomechanical and gene expression changes in response to increased right ventricular pressure overload

Pulmonary hypertension (PH) results in right ventricular (RV) pressure overload and eventual failure. Current research efforts have focused on the RV while overlooking the left ventricle (LV), which is responsible for mechanically assisting the RV during contraction. The objective of this study is to evaluate the biomechanical and gene expression changes occurring in the LV due to RV pressure overload in a mouse model. Nine male mice were divided into two groups: (a) pulmonary arterial banding (PAB, N = 4) and (b) sham surgery (Sham, N = 5). Tagged and steady‐state free precision cardiac MRI was performed on each mouse at 1, 4, and 7 weeks after surgery. At/week7, the mice were euthanized following right/left heart catheterization with RV/LV tissue harvested for histology and gene expression (using RT‐PCR) studies. Compared to Sham mice, the PAB group revealed a significantly decreased LV and RV ejection fraction, and LV maximum torsion and torsion rate, within the first week after banding. In the PAB group, there was also a slight but significant increase in LV perivascular fibrosis, which suggests elevated myocardial stress. LV fibrosis was also accompanied with changes in gene expression in the hypertensive group, which was correlated with LV contractile mechanics. In fact, principal component (PC) analysis of LV gene expression effectively separated Sham and PAB mice along PC2. Changes in LV contractile mechanics were also significantly correlated with unfavorable changes in RV contractile mechanics, but a direct causal relationship was not established. In conclusion, a purely biomechanical insult of RV pressure overload resulted in biomechanical and transcriptional changes in both the RV and LV. Given that the RV relies on the LV for contractile energy assistance, considering the LV could provide prognostic and therapeutic targets for treating RV failure in PH.

Pulmonary arterial banding in mice may be a suitable model for studies on ventricular mechanics in pediatric pulmonary arterial hypertension

BACKGROUND

The role of interventricular mechanics in pediatric pulmonary arterial hypertension (PAH) and its relation to right ventricular (RV) dysfunction has been largely overlooked. Here, we characterize the impact of maintained pressure overload in the RV-pulmonary artery (PA) axis on myocardial strain and left ventricular (LV) mechanics in pediatric PAH patients in comparison to a preclinical PA-banding (PAB) mouse model. We hypothesize that the PAB mouse model mimics important aspects of interventricular mechanics of pediatric PAH and may be beneficial as a surrogate model for some longitudinal and interventional studies not possible in children.

METHODS

Balanced steady-state free precession (bSSFP) cardiovascular magnetic resonance (CMR) images of 18 PAH and 17 healthy (control) pediatric subjects were retrospectively analyzed using CMR feature-tracking (FT) software to compute measurements of myocardial strain. Furthermore, myocardial tagged-CMR images were also analyzed for each subject using harmonic phase flow analysis to derive LV torsion rate. Within 48 h of CMR, PAH patients underwent right heart catheterization (RHC) for measurement of PA/RV pressures, and to compute RV end-systolic elastance (RV_Ees, a measure of load-independent contractility). Surgical PAB was performed on mice to induce RV pressure overload and myocardial remodeling. bSSFP-CMR, tagged CMR, and intra-cardiac catheterization were performed on 12 PAB and 9 control mice (Sham) 7 weeks after surgery with identical post-processing as in the aforementioned patient studies. RV_Ees was assessed via the single beat method.

RESULTS

LV torsion rate was significantly reduced under hypertensive conditions in both PAB mice (p = 0.004) and pediatric PAH patients (p < 0.001). This decrease in LV torsion rate correlated significantly with a decrease in RV_Ees in PAB (r = 0.91, p = 0.05) and PAH subjects (r = 0.51, p = 0.04). In order to compare combined metrics of LV torsion rate and strain parameters principal component analysis (PCA) was used. PCA revealed grouping of PAH patients with PAB mice and control subjects with Sham mice. Similar to LV torsion rate, LV global peak circumferential, radial, and longitudinal strain were significantly (p < 0.05) reduced under hypertensive conditions in both PAB mice and children with PAH.

CONCLUSIONS

The PAB mouse model resembles PAH-associated myocardial mechanics and may provide a potential model to study mechanisms of RV/LV interdependency.

Changes in the expression of cardiac genes responsive to thyroid hormones in the chickens with cold-induced pulmonary hypertension

Cold stress is an environmental cause of pulmonary hypertension syndrome (PHS) in broiler chickens. This factor could increase the rate of metabolic activity via thyroid hormones (T3 and T4). To evaluate the effect of these hormones on the heart, the plasma concentration of T3, T4, and the gene expression of their receptors (THRα and THRβ) and many contractile proteins (ACTC1, MHCα, MHCβ, RYR2, SERCA2, THRα, THRβ, and troponin I) were measured in the right ventricle in 2 periods of age (21 and 35 d). Plasma T3 concentration was significantly higher in the PHS group of chickens than in the control one at 21 and 35 d while plasma T4 did not change. The relative expression of MHCα, RYR2, SERCA2, and THRα genes in the right ventricle tissues was only higher in PHS group of broilers than control group at 21 d (P < 0.05) whereas the expression of ACTC1, MHCβ, and troponin I did not differ at 2 periods of age. The positive correlations between MHCα, RYR2, SERCA2, and T3, THRα were confirmed. The expression of THRβ gene was only higher in PHS group of broilers than control at 35 d (P < 0.05). The data determined that cold stress could increase thyroid hormones and the gene expression of their receptor (THRα) in the pick of chicken growth (21 d) that they themselves elevates the expression of many genes related to contractile elements (MHCα, RYR2, and SERCA2), leading to adaptive right ventricle hypertrophy.

Cardiac Magnetic Resonance Imaging in Pulmonary Arterial Hypertension: Ready for Clinical Practice and Guidelines?

Purpose of Review

Pulmonary arterial hypertension (PAH) is a progressive disease with high mortality. A greater understanding of the physiology and function of the cardiovascular system in PAH will help improve survival. This review covers the latest advances within cardiovascular magnetic resonance imaging (CMR) regarding diagnosis, evaluation of treatment, and prognostication of patients with PAH.

Recent Findings

New CMR measures that have been proven relevant in PAH include measures of ventricular and atrial volumes and function, tissue characterization, pulmonary artery velocities, and arterio-ventricular coupling.

Summary

CMR markers carry prognostic information relevant for clinical care such as treatment response and thereby can affect survival. Future research should investigate if CMR, as a non-invasive method, can improve existing measures or even provide new and better measures in the diagnosis, evaluation of treatment, and determination of prognosis of PAH.

Mechanical Circulatory Support in Right Ventricular Failure

Right ventricular dysfunction presents unique challenges in patients with cardiopulmonary disease. When optimal medical therapy fails, mechanical circulatory support is considered. Devices can by classified according to whether they are deployed percutaneously or surgically, whether the pump is axial or centrifugal, whether the right ventricle is bypassed directly or indirectly, and whether the support is short term or long term. Each device has advantages and disadvantages. Acute mechanical circulatory support is a suitable temporizing strategy in advanced heart failure. Future research in right ventricular mechanical circulatory support will optimize device management, refine patient selection, and ultimately improve clinical outcomes.

Right ventricular myocardial mechanics: Multi-modal deformation, microstructure, modeling, and comparison to the left ventricle

The right ventricular myocardium, much like the rest of the right side of the heart, has been consistently understudied. Presently, little is known about its mechanics, its microstructure, and its constitutive behavior. In this work, we set out to provide the first data on the mechanics of the mature right ventricular myocardium in both simple shear and uniaxial loading and to compare these data to the mechanics of the left ventricular myocardium. To this end, we tested ovine tissue samples of the right and left ventricle under a comprehensive mechanical testing protocol that consisted of six simple shear modes and three tension/compression modes. After mechanical testing, we conducted a histology-based microstructural analysis on each right ventricular sample that yielded high resolution fiber distribution maps across the entire samples. Equipped with this detailed mechanical and histological data, we employed an inverse finite element framework to determine the optimal form and parameters for microstructure-based constitutive models. The results of our study show that right ventricular myocardium is less stiff then the left ventricular myocardium in the fiber direction, but similarly exhibits non-linear, anisotropic, and tension/compression asymmetric behavior with direction-dependent Poynting effect. In addition, we found that right ventricular myocardial fibers change angles transmurally and are dispersed within the sheet plane and normal to it. Through our inverse finite element analysis, we found that the Holzapfel model successfully fits these data, even when selectively informed by rudimentary microstructural information. And, we found that the inclusion of higher-fidelity microstructural data improved the Holzapfel model's predictive ability. Looking forward, this investigation is a critical step towards understanding the fundamental mechanical behavior of right ventricular myocardium and lays the groundwork for future whole-organ mechanical simulations.

Better Outcomes in Pulmonary Arterial Hypertension After Repair of Congenital Heart Disease, Compared With Idiopathic Pulmonary Arterial Hypertension

Background

Pulmonary vascular changes in postoperative pulmonary artery hypertension (PAH) are similar to those seen in idiopathic PAH. Data are sparse on direct comparative midterm outcomes for these 2 high-risk populations.

Methods

Patients with idiopathic or postoperative PAH referred to a large tertiary hospital between June 2005 and July 2019 were retrospectively evaluated.

Results

A total of 364 consecutive patients were studied, including 201 postoperative PAH patients and 163 patients with idiopathic PAH, with a median age of 18.7 (interquartile range 10.0, 31.5) and 7.3 (IQR: 2.9, 18.3) years, respectively. PAH-specific drugs were used in 77.7% of patients; 31.4% received combination therapy. Patients with idiopathic PAH had a shorter 6-mintue walk distance, lower percutaneous oxygen saturation, and higher B-type natriuretic peptide levels than those with postoperative PAH at diagnosis (all P < 0.001), During a median follow-up time of 3.4 (interquartile range: 2.1, 5.8) years, 56 patients (15.4%) died, and one underwent bilateral lung transplantation. Patients with postoperative PAH had better survival than those with idiopathic PAH, according to age (hazard ratio [HR] 0.128, 95% confidence interval [CI]: 0.07-0.22, P < 0.0001); Kaplan–Meier survival estimates at 5 years for idiopathic and postoperative PAH patients were 74.3% and 92.6%, respectively. Patients in New York Heart Association functional class III–IV had an over 4-fold increased risk of death (HR 4.85, 95% CI: 2.61-9.00, P < 0.0001). Patients < 18 years of age at idiopathic PAH diagnosis had a worse survival compared to adult patients (HR 6.90, 95% CI: 4.19-15.56, P = 0.040).

Conclusions

Postoperative-PAH patients had better midterm survival compared to patients with idiopathic PAH. Mortality was significant in both PAH groups, reinforcing the need for early diagnosis and optimal individualized management to improve outcomes.

Evaluating the Right Ventricle in Acute and Chronic Pulmonary Embolism: Current and Future Considerations

The right ventricle (RV), due to its morphologic and physiologic differences, is susceptible to sudden increase in RV afterload, as noted in patients with acute pulmonary embolism (PE). Functional impairment of RV function is a stronger presage of adverse outcomes in acute PE than the location or burden of emboli. While current iterations of most clinical prognostic scores do not incorporate RV dysfunction, advancements in imaging have enabled more granular and accurate assessment of RV dysfunction in acute PE. RV enlargement and dysfunction on imaging is noted only in a subset of patients with acute PE and is dependent on underlying cardiopulmonary reserve and clot burden. Specific signs like McConnell's and "60/60" sign are noted in less than 20% of patients with acute PE. About 2% of patients with acute PE develop chronic thromboembolic pulmonary hypertension, characterized by continued deterioration in RV function in a subset of patients with a continuum of RV function from preserved to overt right heart failure. Advances in molecular and other imaging will help better characterize RV dysfunction in this population and evaluate the response to therapies.

Impact of Annulus-Sparing on Surgical Adequacy of Pulmonary Valve in Complete Repair of Tetralogy of Fallot with Right Ventricular Outflow Tract Incision

Today, strategy of repair remains controversial and rare analyses on annular integrity associated with outcomes in complete repair by RVOT incision were performed in a large TOF cohort in China. This is a retrospective cohort study involving patients with TOF who had undergone complete repair by RVOT incision between January 2012 and December 2017 in Fuwai hospital. The primary outcome was a composite of reintervention, significant pulmonary regurgitation (PR) and significant annular peak gradient (APG). Multivariate Cox proportional-hazards model analyses were used to assess the relationships between annular integrity and outcomes. In total, 1673 survival patients with the median age of 318 days were included, and 1002 were male. During a median follow-up of 49 months, 538 participants developed the primary outcome (27 reinterventions). Multivariate Cox analyses showed that compared with AS, TAP was associated with an increased risk of primary outcome (adjusted HR, 1.94 [95% CI 1.60-2.37]) and the results remained unchanged even in most subgroups defined. In secondary outcomes analyses, TAP is associated with a higher risk of reintervention (adjusted HR, 3.32 [95% CI 1.25-8.79]) and significant PR (adjusted HR, 2.51 [95% CI 2.00-3.16]). However, TAP is not associated with a decreased risk of significant APG (adjusted HR, 1.33 [95% CI 0.94-1.88]). PVA integrity preservation is important in complete repair of TOF with RVOT incision. TAP is associated with a higher risk of reintervention and significant PR, and with a similar risk of significant APG. Significant APG in AS patients at discharge has a downtrend over time.

Perioperative Right Ventricular Dysfunction: Analysis of Outcomes

Right ventricular dysfunction (RVD) is a well-known prognostic factor for adverse outcomes in cardiovascular medicine. The right ventricle (RV) in medically managed heart failure patients and in surgical patients perioperatively generally is overshadowed by left ventricular disease. However, with advancement of various diagnostic tools and better understanding of its functional anatomy, the role of the RV is emerging in many clinical conditions. The failure of one ventricle has significant effect on the function of the other ventricle and it is predominantly due to ventricular interdependence.¹ The etiology of RVD is multifactorial and irrespective of etiology. RVD has been associated with significant increases in morbidity and mortality in various clinical scenarios.^2,3 The primary objective of this comprehensive review is to analyze various etiology-related outcomes of RVD in the perioperative population.

Continuous Aerobic Exercise Prevents Detrimental Remodeling and Right Heart Myocyte Contraction and Calcium Cycling Dysfunction in Pulmonary Artery Hypertension

ABSTRACT

Pulmonary artery hypertension (PAH) imposes right heart and lung detrimental remodeling which impairs cardiac contractility, physical effort tolerance, and survival. The effects of an early moderate-intensity continuous aerobic exercise training on the right ventricle and lung structure, and on contractility and the calcium (Ca2+) transient in isolated myocytes from rats with severe PAH induced by monocrotaline were analyzed. Rats were divided into control sedentary (CS), control exercise (CE), monocrotaline sedentary (MS), and monocrotaline exercise (ME) groups. Animals from control exercise and ME groups underwent a moderate-intensity aerobic exercise on a treadmill (60 min/d; 60% intensity) for 32 days, after a monocrotaline (60 mg/kg body weight i.p.) or saline injection. The pulmonary artery resistance was higher in MS than in control sedentary (1.36-fold) and was reduced by 39.39% in ME compared with MS. Compared with MS, the ME group presented reduced alveolus (17%) and blood vessel (46%) wall, fibrosis (25.37%) and type I collagen content (55.78%), and increased alveolus (52.96%) and blood vessel (146.97%) lumen. In the right ventricle, the ME group exhibited diminished hypertrophy index (25.53%) and type I collagen content (40.42%) and improved myocyte contraction [ie, reduced times to peak (29.27%) and to 50% relax (13.79%)] and intracellular Ca2+ transient [ie, decreased times to peak (16.06%) and to 50% decay (7.41%)] compared with MS. Thus, early moderate-intensity continuous aerobic exercise prevents detrimental remodeling in the right heart and lung increases in the pulmonary artery resistance and dysfunction in single myocyte contraction and Ca2+ cycling in this model.

Therapeutic hypothermia after cardiac arrest during living-donor liver transplant surgery: A case report

RATIONALE

Therapeutic hypothermia is an effective medical treatment for neurological recovery after cardiac arrest. Here, we describe a case of successful mild therapeutic hypothermia after cardiac arrest during living-donor liver transplantation.

PATIENT CONCERNS

A 54-year-old woman with alcoholic liver cirrhosis was admitted for living-donor liver transplantation. Cardiac arrest occurred during the anhepatic phase. After cardiopulmonary resuscitation, spontaneous circulation returned, but the bispectral index level remained below 10 until the end of surgery.

DIAGNOSES

Neurological injury caused by global cerebral hypoperfusion was suspected.

INTERVENTIONS

The patient was treated with mild therapeutic hypothermia for 24hours after resuscitation targeting a core body temperature of 34°C with surface cooling using ice bags.

OUTCOMES

The patient recovered consciousness about 22 hours after the event. However, she showed symptoms of delirium even when discharged. At the 3-month follow-up exam, she showed no specific neurological complications. The transplanted liver showed no problems with regeneration.

LESSONS

Mild therapeutic hypothermia may be safely adopted in cases of cardiac arrest in liver transplant patients and is beneficial for neurological recovery.

Autogenous mitochondria transplantation for treatment of right heart failure

BACKGROUND

Right ventricular hypertrophy and failure are major causes of cardiac morbidity and mortality. A key event in the progression to right ventricular hypertrophy and failure is cardiomyocyte apoptosis due to mitochondrial dysfunction. We sought to determine whether localized intramyocardial injection of autologous mitochondria from healthy muscle treats heart failure.

METHODS

Mitochondria transplanted from different sources were initially tested in cultured hypertrophic cardiomyocytes. A right ventricular hypertrophy/right ventricular failure model created through banding of the pulmonary artery in immature piglets was used for treatment with autologous mitochondria (pulmonary artery banded mitochondria injected/treated n = 6) from calf muscle, versus vehicle (pulmonary artery banded vehicle injected/treated n = 6) injected into the right ventricular free-wall, and compared with sham-operated controls (sham, n = 6). Animals were followed for 8 weeks by echocardiography (free-wall thickness, contractility), and dp/dt max was measured concomitantly with cardiomyocyte hypertrophy, fibrosis, and apoptosis at study end point.

RESULTS

Internalization of mitochondria and adenosine triphosphate levels did not depend on the source of mitochondria. At 4 weeks, banded animals showed right ventricular hypertrophy (sham: 0.28 ± 0.01 cm vs pulmonary artery banding: 0.4 ± 0.02 cm wall thickness; P = .001), which further increased in pulmonary artery banded mitochondria injected/treated but declined in pulmonary artery banded vehicle injected/treated (0.47 ± 0.02 cm vs 0.348 ± 0.03 cm; P = .01). Baseline contractility was not different but was significantly reduced in pulmonary artery banded vehicle injected/treated compared with pulmonary artery banded mitochondria injected/treated and so was dp/dtmax. There was a significant difference in apoptotic cardiomyocyte loss and fibrosis in sham versus hypertrophied hearts with most apoptosis in pulmonary artery banded vehicle injected/treated hearts (sham: 1 ± 0.4 vs calf muscle vs vehicle: 13 ± 1.7; P = .001 and vs pulmonary artery banded mitochondria injected/treated: 8 ± 1.9, P = .01; pulmonary artery banded vehicle injected/treated vs pulmonary artery banded mitochondria injected/treated, P = .05).

CONCLUSIONS

Mitochondrial transplantation allows for prolonged physiologic adaptation of the pressure-loaded right ventricular and preservation of contractility by reducing apoptotic cardiomyocyte loss.

Growth factors in pulmonary arterial hypertension: Focus on preserving right ventricular function

Pulmonary arterial hypertension (PAH) is a rare and progressive disease, characterized by increased vascular resistance leading to right ventricle (RV) failure. The extent of right ventricular dysfunction crucially influences disease prognosis; however, currently no therapies have specific cardioprotective effects. Besides discussing the pathophysiology of right ventricular adaptation in PAH, this review focuses on the roles of growth factors (GFs) in disease pathomechanism. We also summarize the involvement of GFs in the preservation of cardiomyocyte function, to evaluate their potential as cardioprotective biomarkers and novel therapeutic targets in PAH.