Evaluation of pulmonary artery stiffness in pulmonary hypertension with cardiac magnetic resonance

Positive Vasoreactivity Testing in Pulmonary Arterial Hypertension: Therapeutic Consequences, Treatment Patterns, and Outcomes in the Modern Management Era

BACKGROUND

Among patients with pulmonary arterial hypertension (PAH), acute vasoreactivity testing during right heart catheterization may identify acute vasoresponders, for whom treatment with high-dose calcium channel blockers (CCBs) is recommended. However, long-term outcomes in the current era remain largely unknown. We sought to evaluate the implications of acute vasoreactivity response for long-term response to CCBs and other outcomes.

METHODS

Patients diagnosed with PAH between January 1999 and December 2018 at 15 pulmonary hypertension centers were included and analyzed retrospectively. In accordance with current guidelines, acute vasoreactivity response was defined by a decrease of mean pulmonary artery pressure by ≥10 mm Hg to reach <40 mm Hg, without a decrease in cardiac output. Long-term response to CCBs was defined as alive with unchanged initial CCB therapy with or without other initial PAH therapy and World Health Organization functional class I/II and/or low European Society of Cardiology/European Respiratory Society risk status at 12 months after initiation of CCBs. Patients were followed for up to 5 years; clinical measures, outcome, and subsequent treatment patterns were captured.

RESULTS

Of 3702 patients undergoing right heart catheterization for PAH diagnosis, 2051 had idiopathic, heritable, or drug-induced PAH, of whom 1904 (92.8%) underwent acute vasoreactivity testing. A total of 162 patients fulfilled acute vasoreactivity response criteria and received an initial CCB alone (n=123) or in combination with another PAH therapy (n=39). The median follow-up time was 60.0 months (interquartile range, 30.8-60.0), during which overall survival was 86.7%. At 12 months, 53.2% remained on CCB monotherapy, 14.7% on initial CCB plus another initial PAH therapy, and the remaining patients had the CCB withdrawn and/or PAH therapy added. CCB long-term response was found in 54.3% of patients. Five-year survival was 98.5% in long-term responders versus 73.0% in nonresponders. In addition to established vasodilator responder criteria, pulmonary artery compliance at acute vasoreactivity testing, low risk status and NT-proBNP (N-terminal pro-B-type natriuretic peptide) levels at early follow-up correlated with long-term response and predicted survival.

CONCLUSIONS

Our data display heterogeneity within the group of vasoresponders, with a large subset failing to show a sustained satisfactory clinical response to CCBs. This highlights the necessity for comprehensive reassessment during early follow-up. The use of pulmonary artery compliance in addition to current measures may better identify those likely to have a good long-term response.

Insights Into Differences in Pulmonary Hemodynamics in Hispanic Patients With Pulmonary Arterial Hypertension

Background

Emerging data suggest that Hispanic patients with pulmonary arterial hypertension (PAH) exhibit improved survival rates compared to individuals of other ethnicities with similar baseline hemodynamics. However, the underlying reasons for this survival advantage remain unclear. This study focused on comparing pulmonary hemodynamics in Hispanic and non-Hispanic PAH patients and how these differences may contribute to varied clinical outcomes.

Methods

A retrospective analysis of right heart catheterization data was conducted on a treatment-naive PAH patient cohort from a single center.

Results

Over a 10-year period, a total of 226 PAH patients were identified, of which 138 (61%) were Hispanic and 88 (39%) were non-Hispanic. Hispanic patients presented with lower pulmonary artery pressures, lower pulmonary vascular resistance, and exhibited significantly higher pulmonary arterial compliance (PAc). Hispanic patients had better 5-year survival rates.

Conclusions

This study highlights the importance of exploring phenotypic differences in ethnically diverse PAH cohorts.

Feasibility, Repeatability, and Correlation to Lung Function of Phase-Resolved Functional Lung (PREFUL) MRI-derived Pulmonary Artery Pulse Wave Velocity Measurements

BACKGROUND

Pulse wave velocity (PWV) in the pulmonary arteries (PA) is a marker of vascular stiffening. Currently, only phase-contrast (PC) MRI-based options exist to measure PA-PWV.

PURPOSE

To test feasibility, repeatability, and correlation to clinical data of Phase-Resolved Functional Lung (PREFUL) MRI-based calculation of PA-PWV.

STUDY TYPE

Retrospective.

SUBJECTS

79 (26 female) healthy subjects (age range 19-78), 58 (24 female) patients with chronic obstructive pulmonary disease (COPD, age range 40-77), 60 (33 female) patients with suspected pulmonary hypertension (PH, age range 28-85).

SEQUENCE

2D spoiled gradient echo, 1.5T.

ASSESSMENT

PA-PWV was measured from PREFUL-derived cardiac cycles based on the determination of temporal and spatial distance between lung vasculature voxels using a simplified (sPWV) method and a more comprehensive (cPWV) method including more elaborate distance calculation. For 135 individuals, PC MRI-based PWV (PWV-QA) was measured.

STATISTICAL TESTS

Intraclass-correlation-coefficient (ICC) and coefficient of variation (CoV) were used to test repeatability. Nonparametric tests were used to compare cohorts. Correlation of sPWV/cPWV, PWV-QA, forced expiratory volume in 1 sec (FEV1 ) %predicted, residual volume (RV) %predicted, age, and right heart catheterization (RHC) data were tested. Significance level α = 0.05 was used.

RESULTS

sPWV and cPWV showed no significant differences between repeated measurements (P-range 0.10-0.92). CoV was generally lower than 15%. COPD and PH patients had significantly higher sPWV and cPWV than healthy subjects. Significant correlation was found between sPWV or cPWV and FEV1 %pred. (R = -0.36 and R = -0.44), but not with RHC (P-range -0.11 - 0.91) or age (P-range 0.23-0.89). Correlation to RV%pred. was significant for cPWV (R = 0.42) but not for sPWV (R = 0.34, P = 0.055). For all cohorts, sPWV and cPWV were significantly correlated with PWV-QA (R = -0.41 and R = 0.48).

DATA CONCLUSION

PREFUL-derived PWV is feasible and repeatable. PWV is increased in COPD and PH patients and correlates to airway obstruction and hyperinflation.

LEVEL OF EVIDENCE

3 TECHNICAL EFFICACY: Stage 2.

Assessing the prognostic significance of mean pulmonary artery velocity in heart failure with slightly reduced ejection fraction

OBJECTIVE

In this study, we assessed the prognostic significance of the mean velocity of the pulmonary artery (mvPA) using CMR in patients who have heart failure with mildly reduced ejection fraction (HFmrEF) and pulmonary hypertension, both as a combined condition and individually.

METHODS

This retrospective study involved 284 consecutive patients diagnosed with HFmrEF who were hospitalized and underwent CMR imaging to assess RV-PA coupling parameters, including mvPA. We collected baseline data clinical profiles, lab test results, and cardiac imaging findings of patients with HFmrEF who had at least two echocardiograms conducted three months apart. The primary endpoint was a composite of all-cause mortality or readmission due to heart failure.

RESULTS

A total of 139 patients met the primary endpoint during an average follow-up of 49 months. The most effective threshold value for predicting the primary endpoint, determined by a receiver operating curve analysis, was 9. cm/s for mvPA. According to the Kaplan-Meier survival plots, when mvPA ≤ 9.05 cm/s, there was a significantly higher mortality rate (Log-Rank: 71.93, p < 0.001). It is important to highlight that the predictive value of mvPA remained consistent, irrespective of RV function. mvPA ≤ 9.05 cm/s served as an independent prognostic indicator, alongside ischemic cardiomyopathy and hyponatremia.

CONCLUSIONS

mvPA has affirmed its significance as an initial prognostic indicator by identifying a group of high-risk patients who have sustained RV function. While the results of this study displayed potential in stratifying the extended prognosis of patients with HFmrEF, additional research is required.

Characterization of pulmonary arterial stiffness using cardiac MRI

Pulmonary arterial stiffness (PAS) is a pathologic hallmark of all types of pulmonary hypertension (PH). Cardiac MRI (CMR), a gold-standard imaging modality for the evaluation of pulmonary flow, biventricular morphology and function has been historically reserved for the longitudinal clinical follow-up, PH phenotyping purposes, right ventricular evaluation, and research purposes. Over the last two decades, numerous indices combining invasive catheterization and non-invasive CMR have been utilized to phenotype the character and severity of PAS in different types of PH and to assess its clinically prognostic potential with encouraging results. Many recent studies have demonstrated a strong role of CMR derived PAS markers in predicting long-term clinical outcomes and improving currently gold standard risk assessment provided by the REVEAL calculator. With the utilization of a machine learning strategies, strong diagnostic and prognostic performance of CMR reported in multicenter studies, and ability to detect PH at early stages, the non-invasive assessment of PAS is on verge of routine clinical utilization. In this review, we focus on appraising important CMR studies interrogating PAS over the last 20 years, describing the benefits and limitations of different PAS indices, and their pathophysiologic relevance to pulmonary vascular remodeling. We also discuss the role of CMR and PAS in clinical surveillance and phenotyping of PH, and the long-term future goal to utilize PAS as a biomarker to aid with more targeted therapeutic management.

Aldehyde Dehydrogenase 2 (ALDH2) rs671 Polymorphism is a Predictor of Pulmonary Hypertension Due to Left Heart Disease

AIM

Pulmonary hypertension due to left heart disease (PH-LHD) is commonly seen in patients with heart failure (HF), but there are limited treatment options. Recent studies have shown an association between aldehyde dehydrogenase 2 (ALDH2) rs671 polymorphisms and pulmonary hypertension (PH). Therefore, this study aimed to investigate the occurrence of ALDH2 rs671 polymorphisms, and the association between ALDH2 and risk of PH-LHD in patients with HF. It also investigated different ALDH2 genotypes and examined their association with cardiac structure and function in HF patients with PH-LHD.

METHODS

A total of 178 HF patients were consecutively enrolled in this study: 102 without PH-LHD and 76 with PH-LHD. Clinical data, parameters of echocardiography, and relevant biochemical indexes were recorded in both groups. Differences in data obtained between groups were compared, and the risk of variant ALDH2 polymorphisms with PH-LHD in HF patients was analysed using univariate and multivariate logistic regression.

RESULTS

The prevalence of ALDH2 rs671 GA/AA polymorphisms (variant ALDH2) was 24 of 102 patients (23.53%) in the HF without PH-LHD group, and 32 of 76 patients (42.10%) in the HF with PH-LHD group, with a statistically significant difference. Univariate and multivariate logistical regression showed that variant ALDH2 is an independent risk factor for HF combined with PH-LHD. A higher proportion of patients with variant ALDH2 in the HF with PH-LHD group had a tricuspid regurgitation velocity >2.8 m/s, and they had higher values of peak early diastolic velocity of the mitral orifice/peak velocity of the early diastolic wave of the mitral orifice, maximum frequency shift of pulmonary valve flow, and pulmonary artery stiffness.

CONCLUSIONS

Variant ALDH2 may be an independent risk factor for HF combined with PH-LHD. Variant ALDH2 may also be involved in pulmonary artery remodelling and is a potential new target for clinical treatment of PH-LHD.

Noninvasive evaluation of pulmonary artery stiffness in heart failure patients via cardiovascular magnetic resonance

Heart failure (HF) presents manifestations in both cardiac and vascular abnormalities. Pulmonary hypertension (PH) is prevalent in up 50% of HF patients. While pulmonary arterial hypertension (PAH) is closely associated with pulmonary artery (PA) stiffness, the association of HF caused, post-capillary PH and PA stiffness is unknown. We aimed to assess and compare PA stiffness and blood flow hemodynamics noninvasively across HF entities and control subjects without HF using CMR. We analyzed data of a prospectively conducted study with 74 adults, including 55 patients with HF across the spectrum (20 HF with preserved ejection fraction [HFpEF], 18 HF with mildly-reduced ejection fraction [HFmrEF] and 17 HF with reduced ejection fraction [HFrEF]) as well as 19 control subjects without HF. PA stiffness was defined as reduced vascular compliance, indicated primarily by the relative area change (RAC), altered flow hemodynamics were detected by increased flow velocities, mainly by pulse wave velocity (PWV). Correlations between the variables were explored using correlation and linear regression analysis. PA stiffness was significantly increased in HF patients compared to controls (RAC 30.92 ± 8.47 vs. 50.08 ± 9.08%, p < 0.001). PA blood flow parameters were significantly altered in HF patients (PWV 3.03 ± 0.53 vs. 2.11 ± 0.48, p < 0.001). These results were consistent in all three HF groups (HFrEF, HFmrEF and HFpEF) compared to the control group. Furthermore, PA stiffness was associated with higher NT-proBNP levels and a reduced functional status. PA stiffness can be assessed non-invasively by CMR. PA stiffness is increased in HFrEF, HFmrEF and HFpEF patients when compared to control subjects.Trial registration The study was registered at the German Clinical Trials Register (DRKS, registration number: DRKS00015615).

Reduced Pulmonary Artery Distensibility Predicts Persistent Pulmonary Hypertension and 2-Year Mortality in Patients with Severe Aortic Stenosis Undergoing TAVR

RATIONALE AND OBJECTIVES

Post-TAVR persistent pulmonary hypertension (PH) is a better predictor of poor outcome than pre-TAVR PH. In this longitudinal study we sought to evaluate whether pulmonary artery (distensibility (DPA) measured on preprocedural ECG-gated CTA is associated with persistent-PH and 2-year mortality after TAVR.

MATERIALS AND METHODS

Three hundred and thirty-six patients undergoing TAVR between July 2012 and March 2016 were retrospectively included and followed for all-cause mortality until November 2017. All patients underwent retrospectively ECG-gated CTA prior to TAVR. Main pulmonary artery (MPA) area was measured in systole and in diastole. DPA was calculated as: [(area-MPAmax-area-MPAmin)/area-MPAmax]%. ROC analysis was performed to assess the AUC for persistent-PH. Youden Index was used to determine the optimal threshold of DPA for persistent-PH. Two groups were compared based on a DPA threshold of 8% (specificity of 70% for persistent-PH). Kaplan-Meier, Cox proportional-hazard, and logistic regression analyses were performed. The primary clinical endpoint was defined as persistent-PH post-TAVR. The secondary endpoint was defined as all-cause mortality 2 years after TAVR.

RESULTS

Median follow-up time was 413 (interquartiles 339-757) days. A total of 183 (54%) had persistent-PH and 68 (20%) patients died within 2-years after TAVR. Patients with DPA<8% had significantly more persistent-PH (67% vs 47%, p<0.001) and 2-year deaths (28% vs 15%, p=0.006), compared to patients with DPA>8%. Adjusted multivariable regression analyses showed that DPA<8% was independently associated with persistent-PH (OR 2.10 [95%-CI 1.3-4.5], p=0.007) and 2-year mortality (HR 2.91 [95%-CI 1.5-5.8], p=0.002). Kaplan-Meier analysis showed that 2-year mortality of patients with DPA<8% was significantly higher compared to patients with DPA≥8% (mortality 28% vs 15%; log-rank p=0.003).

CONCLUSION

DPA on preprocedural CTA is independently associated with persistent-PH and two-year mortality in patients who undergo TAVR.

Predictive value of reduced pulmonary arterial elasticity in acute pulmonary embolism for right ventricular dysfunction

BACKGROUND

Computed tomography pulmonary angiography (CTPA) yields indices, such as the right ventricular/left ventricular (RV/LV) ratio > 1.0, which are commonly used for risk stratification of patients with acute pulmonary embolism (APE). Although pulmonary artery elasticity (PAE) has been previously described, its relationship with right ventricular dysfunction (RVD) has not been explored. Here, we investigated whether PAE, measured using CTPA, is associated with RVD.

METHODS

Patients who underwent retrospective electrocardiogram-gated CTPA and had a definitive diagnosis of APE were included in the study. The subjects were classified into RVD and non-RVD groups according to the RVD on echocardiography. PAE, involving aortic distensibility (AD), aortic compliance (AC), and aortic stiffness (ASI), and right heart function indices were compared between the two groups, and their correlations were examined. Receiver operating characteristic (ROC) curves were generated to evaluate the specificity and sensitivity of the RVD prediction.

RESULTS

Thirty-five patients with APE were enrolled in the study (RVD: 18, non-RVD: 17). The groups showed no significant differences in age, sex, number of patients receiving thrombolysis, and number of high-risk conditions (P > 0.05). Regarding PAE parameters, AD was significantly reduced in the RVD group compared to that in the non-RVD group (P < 0.05), whereas AC and ASI were not statistically different (P > 0.05). The ratio of the maximum cross-sectional area of PA and AA (PA/AAmax),the ratio of the minimum cross-sectional area of PA and AA(PA/AAmin), diameter of the coronary sinus, RV/LV diameter, RV/Lvarea, the ratio of the end-diastolic volume of right ventricular and left ventricular (RV/LVDV), the ratio of the end-systolic volume of right ventricular and left ventricular (RV/LVSV) were significantly greater in the RVD group than in the non-RVD group (P < 0.05). Correlation analysis of AD and right heart function parameters showed that AD was negatively correlated with PA/AAmax, PA/AAmin, RV/LV diameter, RV/LVDV, and PAE measured by ultrasound, with correlation coefficients ranging from - 0.336 to - 0.580 (P < 0.05). The ROC curves of AD and RV/LVdiameter to predict RVD had areas under the curve of 0.748 and 0.712, sensitivities of 82.35% and 70.59%, specificities of 66.67% and 72.22%, and cutoff values of 4.9433 and 1.1105, respectively.

CONCLUSION

AD obtained by retrospective ECG-gated CTPA may be helpful in assessing RVD in patients with APE while accurately diagnosing APE. It contributes to timely diagnosis and treatment and improves the prognosis of patients with APE.

The importance of pulmonary pulse transit time in indicating right ventricular dysfunction and pulmonary arterial stiffness in rheumatoid arthritis

SUBJECT

Rheumatoid arthritis patients are at risk of developing cardiovascular disease such as right heart failure and pulmonary hypertension (PH). Arterial stiffness can be used to assess pulmonary hemodynamics. Noninvasive approaches can also be used to assess pulmonary hemodynamics. Recently, there have been reports that pulmonary pulse transit time (PPTT) may also be a useful measure. This study aims to examine the effects of pulmonary hemodynamic alterations on PPTT in RA patients.

METHODS

Forty RA patients and 40 healthy controls were included in the study. Sociodemographic characteristics, laboratory data, and echocardiographic examinations were performed in both groups. Conventional echocardiographic examination included left and right ventricular systolic and diastolic diameters, right ventricular myocardial performance index (RVMPI), right ventricular diastolic function, estimated pulmonary artery systolic pressure (sPAP), tricuspid annular plane systolic excursion (TAPSE), pulmonary artery stiffness (PAS), and PPTT. Right ventricular diastolic and systolic volumes, right ventricular ejection fraction (RVEF), and right ventricular fractional area change (RVFAC) were determined by four-dimensional echocardiography (4DE).

RESULTS

There was no difference between the sPAP values of the patients. RVMPI and PAS were increased in RA patients compared with controls. The PPTT was shortened in RA patients and correlated with RVEF, RVFAC, RVMPI, TAPSE/sPAP, disease duration, and C-reactive protein (CRP). In univariate linear regression analysis, PPTT (p < .001) was thought to be an independent predictor of PAS. RVFAC, disease duration, and PAS were also independent predictors of PPTT.

CONCLUSION

In RA patients, PPTT may be the first evidence of early abnormalities in pulmonary vascular hemodynamics. PPTT and PAS are the values that may predict each other in RA patients. Due to its more practical application, PPTT can be used instead of PAS to assess pulmonary hemodynamics.

Assessment of pulmonary artery stiffness by multiparametric cardiac magnetic resonance-surrogate for right heart catheterization

Background

Cardiac magnetic resonance (CMR) imaging allows for multiparametric assessment of healthy pulmonary artery (PA) hemodynamics. Gender- and aging-associated PA stiffness and pressure alterations have remained clinically unestablished, however may demonstrate epidemiological differences in disease development. The aim of this study is to evaluate the role of CMR as a surrogate for catheter examinations by providing a comprehensive CMR assessment of sex- and age-related reference values for PA stiffness, flow, and pressure.

Methods and Results

PA hemodynamics were studied between gender and age groups (>/<50 years) using phase-contrast CMR. Corresponding correlation analyses were performed. 179 healthy volunteers with a median age of 32.6 years (range 11.3-68.2) were examined. Males demonstrated increased PA compliance (median [interquartile range] or mean ± standard deviation) (20.8 mm2/mmHg [16.6; 25.8] vs. 19.2 ± 7.1 mm2/mmHg; P < 0.033), higher pulse wave velocity (2.00 m/s [1.35; 2.87] vs. 1.73 m/s [1.19; 2.34]; P = 0.018) and a reduced full width half maximum (FWHM) (219 ± 22 ms vs. 235 ± 23 ms; P < 0.001) than females. Mean, systolic, diastolic PA pressure and pulmonary proportional pulse pressure were significantly elevated for males compared to females (P < 0.001). Older subjects (>50 years) exhibited reduced PA elasticity (41.7% [31.0; 52.9] vs. 66.4% [47.7; 83.0]; P < 0.001), reduced PA compliance (15.4 mm2/mmHg [12.3; 20.7] vs. 21.3 ± 6.8 mm2/mmHg; P < 0.001), higher pulse wave velocity (2.59 m/s [1.57; 3.59] vs. 1.76 m/s [1.24; 2.34]; P < 0.001) and a reduced FWHM (218 ± 29 ms vs. 231 ± 21 ms; P < 0.001) than younger subjects.

Conclusions

Velocity-time profiles are dependent on age and gender. PA stiffness indices deteriorate with age. CMR has potential to serve as a surrogate for right heart catheterization.

Pulmonary Artery Strain Predicts Prognosis in Pulmonary Arterial Hypertension

BACKGROUND

Current cardiac magnetic resonance (CMR) imaging in pulmonary arterial hypertension (PAH) focuses on measures of ventricular function and coupling.

OBJECTIVES

The purpose of this study was to evaluate pulmonary artery (PA) global longitudinal strain (GLS) as a prognostic marker in patients with PAH.

METHODS

The authors included 169 patients with PAH from the ASPIRE (Assessing the Spectrum of Pulmonary hypertension Identified at a REferral centre) and INITIATE (Integrated computatioNal modelIng of righT heart mechanIcs and blood flow dynAmics in congeniTal hEart disease) registries, and 82 normal controls with similar age and gender distributions. PA GLS was derived from CMR feature tracking. Right ventricular measurements including volumes, ejection fraction, and right ventricular GLS were also derived from CMR. Patients were followed up a median of 34 months with all-cause mortality as the primary endpoint. Other known risk scores were collected, including the REVEAL (Registry to Evaluate Early and Long-term Pulmonary Arterial Hypertension Disease Management) 2.0 and COMPERA (Comparative, Prospective Registry of Newly Initiated Therapies for Pulmonary Hypertension) 2.0 scores.

RESULTS

Of 169 patients (mean age: 57 ± 15 years; 80% female), 45 (26.6%) died (median follow-up: 34 months). Mean PA GLS was 23% ± 6% in normal controls and 10% ± 5% in patients with PAH (P < 0.0001). Patients with PA GLS <9% had a higher risk of mortality than those with PA GLS ≥9% (P < 0.001), and this was an independent predictor of mortality in PAH on multivariable analysis after adjustment for known risk factors (HR: 2.93; P = 0.010). Finally, in patients with PAH, PA GLS provided incremental prognostic value over the REVEAL 2.0 (global chi-square; P = 0.001; C statistic comparison; P = 0.030) and COMPERA 2.0 (global chi-square; P = 0.001; C statistic comparison; P = 0.048).

CONCLUSIONS

PA GLS confers incremental prognostic utility over the established risk scores for identifying patients with PAH at higher risk of death, who may be targeted for closer monitoring and/or intensified therapy.

Elastin stabilization prevents impaired biomechanics in human pulmonary arteries and pulmonary hypertension in rats with left heart disease

Pulmonary hypertension worsens outcome in left heart disease. Stiffening of the pulmonary artery may drive this pathology by increasing right ventricular dysfunction and lung vascular remodeling. Here we show increased stiffness of pulmonary arteries from patients with left heart disease that correlates with impaired pulmonary hemodynamics. Extracellular matrix remodeling in the pulmonary arterial wall, manifested by dysregulated genes implicated in elastin degradation, precedes the onset of pulmonary hypertension. The resulting degradation of elastic fibers is paralleled by an accumulation of fibrillar collagens. Pentagalloyl glucose preserves arterial elastic fibers from elastolysis, reduces inflammation and collagen accumulation, improves pulmonary artery biomechanics, and normalizes right ventricular and pulmonary hemodynamics in a rat model of pulmonary hypertension due to left heart disease. Thus, targeting extracellular matrix remodeling may present a therapeutic approach for pulmonary hypertension due to left heart disease.

Assessment of Right Ventricular Function-a State of the Art

PURPOSE OF REVIEW

The right ventricle (RV) has a complex geometry and physiology which is distinct from the left. RV dysfunction and failure can be the aftermath of volume- and/or pressure-loading conditions, as well as myocardial and pericardial diseases.

RECENT FINDINGS

Echocardiography, magnetic resonance imaging and right heart catheterisation can assess RV function by using several qualitative and quantitative parameters. In pulmonary hypertension (PH) in particular, RV function can be impaired and is related to survival. An accurate assessment of RV function is crucial for the early diagnosis and management of these patients. This review focuses on the different modalities and indices used for the evaluation of RV function with an emphasis on PH.

[Applying of magnetic resonance tomography for assessment of cardiac remodeling and risk stratification in patients with pulmonary arterial hypertension]

Magnetic resonance imaging - is high precision method for diagnosing cardiovascular diseases. Simultaneously with the anatomy and function of the right ventricle, magnetic resonance imaging allows to assess the pulmonary circulation, which leads to the widespread use of this method in the diagnosis and dynamic monitoring of patients with pulmonary arterial hypertension. The article is devoted to the assessment of cardiac remodeling and risk stratification of this group of patients. Special attention is given to new prognostic parameters included in the scale for risk stratification of patients with pulmonary hypertension of the European Society of Cardiology/European Respiratory Society 2022.

Pulmonary vascular fibrosis in pulmonary hypertension - The role of the extracellular matrix as a therapeutic target

Pulmonary hypertension (PH) is a condition characterized by changes in the extracellular matrix (ECM) deposition and vascular remodeling of distal pulmonary arteries. These changes result in increased vessel wall thickness and lumen occlusion, leading to a loss of elasticity and vessel stiffening. Clinically, the mechanobiology of the pulmonary vasculature is becoming increasingly recognized for its prognostic and diagnostic value in PH. Specifically, the increased vascular fibrosis and stiffening resulting from ECM accumulation and crosslinking may be a promising target for the development of anti- or reverse-remodeling therapies. Indeed, there is a huge potential in therapeutic interference with mechano-associated pathways in vascular fibrosis and stiffening. The most direct approach is aiming to restore extracellular matrix homeostasis, by interference with its production, deposition, modification and turnover. Besides structural cells, immune cells contribute to the level of ECM maturation and degradation by direct cell-cell contact or the release of mediators and proteases, thereby opening a huge avenue to target vascular fibrosis via immunomodulation approaches. Indirectly, intracellular pathways associated with altered mechanobiology, ECM production, and fibrosis, offer a third option for therapeutic intervention. In PH, a vicious cycle of persistent activation of mechanosensing pathways such as YAP/TAZ initiates and perpetuates vascular stiffening, and is linked to key pathways disturbed in PH, such as TGF-beta/BMPR2/STAT. Together, this complexity of the regulation of vascular fibrosis and stiffening in PH allows the exploration of numerous potential therapeutic interventions. This review discusses connections and turning points of several of these interventions in detail.

Right Pulmonary Artery Distensibility Index in Heartworm Infected Dogs: Are the Different Methods Leading to Same Results?

Canine Heartworm Disease (HWD) is mainly a pulmonary vascular disease. The reduction of the Pulmonary Artery Distensibility (PAD) is an early index of pulmonary vascular disease. Echocardiographic evaluation of the Right Pulmonary Artery Distensibility index (RPADi) is calculated as the percentage change in diameter of the right pulmonary artery (RPA) between systole and diastole. Historically, two main methods have been used for RPADi calculation: The Venco method and Visser method; however, different hybrid methods have also been used by other authors. Therefore, it could be difficult for a clinician to decide which method to apply and how to interpret the results based on the reference values reported. The aim of this study was to compare the RPADi obtained by five different techniques (Venco classic, Venco modified, Visser classic, Visser modified 1, and Visser modified 2). The study design was a retrospective, single center, observational study. Forty-seven client-owned dogs were included. The measurements were performed off-line as an average of three consecutive cardiac cycles by a single investigator blinded to the dogs' diagnosis. The RPADi was satisfactorily obtained by all methods in all dogs. Intra-observer measurement variability was clinically acceptable both for systolic and diastolic measurements. Although the Bland-Altman test showed a statistical agreement between the various methods used to calculate the RPADi, these methods cannot be used interchangeably in a clinical setting. Instead, the measurement method and reference values should always be specified.

Combined pre- and post-capillary pulmonary hypertension in left heart disease

Patients with heart failure (HF) often have pulmonary hypertension (PH), which is mainly post-capillary; however, some of them also develop a pre-capillary component. The exact mechanisms leading to combined pre- and post-capillary PH are not yet clear, but the phenomenon seems to start from a passive transmission of increased pressure from the left heart to the lungs, and then continues with the remodeling of both the alveolar and vascular components through different pathways. More importantly, it is not yet clear which patients are predisposed to develop the disease. These patients have some characteristics similar to those with idiopathic pulmonary arterial hypertension (e.g., young age and frequent incidence in female gender), but they share cardiovascular risk factors with patients with HF (e.g., obesity and diabetes), with both reduced and preserved ejection fraction. Thanks to echocardiography parameters and newly introduced scores, more tools are available to distinguish between idiopathic pulmonary arterial hypertension and combined PH and to guide patients' management. It may be hypothesized to treat patients in whom the pre-capillary component is predominant with specific therapies such as those for idiopathic pulmonary arterial hypertension; however, no adequately powered trials of PH-specific treatment are available in combined PH. Early evidence of clinical benefit has been proven in some trials on phosphodiesterase type 5 inhibitors, while data on prostacyclin analogues, endothelin-1 receptor antagonists, and soluble guanylate cyclase stimulators are still controversial.

Strategizing Drug Therapies in Pulmonary Hypertension for Improved Outcomes

Pulmonary hypertension (PH) is characterized by a resting mean pulmonary artery pressure (PAP) of 20 mmHg or more and is a disease of multiple etiologies. Of the various types of PH, pulmonary arterial hypertension (PAH) is characterized by elevated resistance in the pulmonary arterial tree. It is a rare but deadly disease characterized by vascular remodeling of the distal pulmonary arteries. This paper focuses on PAH diagnosis and management including current and future treatment options. Over the last 15 years, our understanding of this progressive disease has expanded from the concept of vasoconstrictive/vasodilatory mismatch in the pulmonary arterioles to now a better appreciation of the role of genetic determinants, numerous cell signaling pathways, cell proliferation and apoptosis, fibrosis, thrombosis, and metabolic abnormalities. While knowledge of its pathophysiology has expanded, the majority of the treatments available today still modulate the same three vasodilatory pathways that have been targeted for over 30 years (endothelin, nitric oxide, and prostacyclin). While modifying these pathways may help improve symptoms and quality of life, none of these directly modify the underlying disease pathogenesis. However, there are now studies ongoing with new drugs that can prevent or reverse these underlying causes of PAH. This review discusses the evidence base for the current treatment algorithms for PAH, as well as discusses novel therapies in development.

Pulmonary hypertension: Linking inflammation and pulmonary arterial stiffening

Pulmonary hypertension (PH) is a progressive disease that arises from multiple etiologies and ultimately leads to right heart failure as the predominant cause of morbidity and mortality. In patients, distinct inflammatory responses are a prominent feature in different types of PH, and various immunomodulatory interventions have been shown to modulate disease development and progression in animal models. Specifically, PH-associated inflammation comprises infiltration of both innate and adaptive immune cells into the vascular wall of the pulmonary vasculature—specifically in pulmonary vascular lesions—as well as increased levels of cytokines and chemokines in circulating blood and in the perivascular tissue of pulmonary arteries (PAs). Previous studies suggest that altered hemodynamic forces cause lung endothelial dysfunction and, in turn, adherence of immune cells and release of inflammatory mediators, while the resulting perivascular inflammation, in turn, promotes vascular remodeling and the progression of PH. As such, a vicious cycle of endothelial activation, inflammation, and vascular remodeling may develop and drive the disease process. PA stiffening constitutes an emerging research area in PH, with relevance in PH diagnostics, prognostics, and as a therapeutic target. With respect to its prognostic value, PA stiffness rivals the well-established measurement of pulmonary vascular resistance as a predictor of disease outcome. Vascular remodeling of the arterial extracellular matrix (ECM) as well as vascular calcification, smooth muscle cell stiffening, vascular wall thickening, and tissue fibrosis contribute to PA stiffening. While associations between inflammation and vascular stiffening are well-established in systemic vascular diseases such as atherosclerosis or the vascular manifestations of systemic sclerosis, a similar connection between inflammatory processes and PA stiffening has so far not been addressed in the context of PH. In this review, we discuss potential links between inflammation and PA stiffening with a specific focus on vascular calcification and ECM remodeling in PH.

Exercise metabolomics in pulmonary arterial hypertension: Where pulmonary vascular metabolism meets exercise physiology

Pulmonary arterial hypertension is an incurable disease marked by dysregulated metabolism, both at the cellular level in the pulmonary vasculature, and at the whole-body level characterized by impaired exercise oxygen consumption. Though both altered pulmonary vascular metabolism and abnormal exercise physiology are key markers of disease severity and pulmonary arterial remodeling, their precise interactions are relatively unknown. Herein we review normal pulmonary vascular physiology and the current understanding of pulmonary vascular cell metabolism and cardiopulmonary response to exercise in Pulmonary arterial hypertension. We additionally introduce a newly developed international collaborative effort aimed at quantifying exercise-induced changes in pulmonary vascular metabolism, which will inform about underlying pathophysiology and clinical management. We support our investigative approach by presenting preliminary data and discuss potential future applications of our research platform.

Data-driven computational models of ventricular-arterial hemodynamics in pediatric pulmonary arterial hypertension

Pulmonary arterial hypertension (PAH) is a complex disease involving increased resistance in the pulmonary arteries and subsequent right ventricular (RV) remodeling. Ventricular-arterial interactions are fundamental to PAH pathophysiology but are rarely captured in computational models. It is important to identify metrics that capture and quantify these interactions to inform our understanding of this disease as well as potentially facilitate patient stratification. Towards this end, we developed and calibrated two multi-scale high-resolution closed-loop computational models using open-source software: a high-resolution arterial model implemented using CRIMSON, and a high-resolution ventricular model implemented using FEniCS. Models were constructed with clinical data including non-invasive imaging and invasive hemodynamic measurements from a cohort of pediatric PAH patients. A contribution of this work is the discussion of inconsistencies in anatomical and hemodynamic data routinely acquired in PAH patients. We proposed and implemented strategies to mitigate these inconsistencies, and subsequently use this data to inform and calibrate computational models of the ventricles and large arteries. Computational models based on adjusted clinical data were calibrated until the simulated results for the high-resolution arterial models matched within 10% of adjusted data consisting of pressure and flow, whereas the high-resolution ventricular models were calibrated until simulation results matched adjusted data of volume and pressure waveforms within 10%. A statistical analysis was performed to correlate numerous data-derived and model-derived metrics with clinically assessed disease severity. Several model-derived metrics were strongly correlated with clinically assessed disease severity, suggesting that computational models may aid in assessing PAH severity.

Evaluation of pulmonary arterial stiffness and comparison with right ventricular functions in patients with cirrhosis preparing for liver transplantation

OBJECTIVE

Pulmonary complications are common in patients with liver cirrhosis. Devolopment of pulmonary hypertension (PH) is associated with a poor prognosis in these patients. Pulmonary arterial stiffness (PAS) is considered an early sign of pulmonary vascular remodeling. The aim of this study is to investigate PAS and compare it with right ventricular (RV) functions in patients with cirrhosis who are scheduled for liver transplantation.

METHODS

The study included 52 cirrhosis patients (mean age 51.01 ± 12.18 years, male gender 76.9%) who were prepared for liver transplantation and 59 age and sex matched (mean age 51.28 ± 13.63 years, male gender 62.7%) healthy individuals. Patients with left ventricular ejection fraction (LVEF) less than 55%, ischemic heart disease, more than mild valvular heart disease, chronic pulmonary disease, congenital heart disease, rheumatic disease, moderate to high echocardiographic PH probability, rhythm or conduction disorders on electrocardiography were excluded from the study. In addition to conventional echocardiographic parameters, PAS value, pulmonary vascular resistance (PVR) and RV ejection efficiency was calculated by the related formulas with transthoracic echocardiography (TTE).

RESULTS

Demographic characteristics and cardiovascular risk factors of the groups were similar. PAS, PVR, and sPAP values were found to be significantly higher in the patient group (20.52 ± 6.52 and 13.73 ± 2.05; 1.43 ± 0.15 and 1.27 ± 0.14; 27.69 ± 3.91 and 23.37 ± 3.81 p < 0.001, respectively). RV FAC and RV Ee were significantly lower and RV MPI was significantly higher in the patient group (45.31 ± 3.85 and 49.66 ± 3.62, p < 0.001; 1.69 ± 0.35 and 1.85 ± 0.23, p = 0.005; 0.39 ± 0.07 and 0.33 ± 0.09, p = 0.001, respectively). PAS was significantly correlated with RV FAC and MPI (r = -0.423, p < 0.001; r = 0.301, p = 0.001, respectively).

CONCLUSIONS

Increased PAS in cirrhosis patients may be associated with early pulmonary vascular involvement. Evaluation of RV functions is important to determine the prognosis in these patients. FAC, MPI, and RV Ee measurements instead of TAPSE or RV S' may be more useful in demonstrating subclinical dysfunction. The correlation of PAS with RV FAC and MPI may indicate that RV subclinical dysfunction is associated with early pulmonary vascular remodeling in patients with liver cirrhosis.

Reduction of Lung Hyperinflation Improves Cardiac Preload, Contractility, and Output in Emphysema: A Prospective Cardiac Magnetic Resonance Study in Patients Who Received Endobronchial Valves

RATIONALE

Pulmonary hyperinflation in patients with Chronic Obstructive Pulmonary Disease (COPD) has been related to smaller cardiac chamber sizes and impaired cardiac function. Nowadays, bronchoscopic lung volume reduction (BLVR) with endobronchial valves is a treatment option to reduce pulmonary hyperinflation in patients with severe emphysema.

OBJECTIVES

We hypothesized that reduction of hyperinflation would improve cardiac preload in this patient group. In addition, we investigated whether the treatment would result in elevated pulmonary artery pressures due to pulmonary vascular bed reduction.

METHODS

We included patients with emphysema and severe hyperinflation (defined by a baseline residual volume >175% of predicted) who were eligible for BLVR with endobronchial valves. Cardiac magnetic resonance imaging was obtained one day prior to treatment and at eight week follow-up. Primary endpoint was cardiac preload, as measured by the right ventricle end-diastolic volume index (RVEDVI). As secondary endpoints, we measured indexed end-diastolic and end-systolic volumes of the right ventricle, left atrium, and left ventricle, pulmonary artery pressures, cardiac output, ejection fraction, and strain.

MEASUREMENTS AND MAIN RESULTS

Twenty-four patients were included. At eight week follow-up, RVEDVI was significantly improved (+7.9 ml/m2, SD 10.0, p=0.001). In addition to increased stroke volumes, we found significantly higher ejection fractions and strain measurements. Although cardiac output was significantly increased (+0.9L/min, SD 1.5, p=0.007), there were no changes in pulmonary artery pressures.

CONCLUSIONS

We found that reduction of hyperinflation using BLVR with endobronchial valves significantly improved cardiac preload, myocardial contractility, and cardiac output, without changes in pulmonary artery pressures. Clinical trial registered with ClinicalTrials.gov (NCT03474471).

Mechanisms of pulmonary vascular dysfunction in pulmonary hypertension and implications for novel therapies

Pulmonary hypertension (PH) is a serious disease characterized by various degrees of pulmonary vasoconstriction and progressive fibroproliferative remodeling and inflammation of the pulmonary arterioles that lead to increased pulmonary vascular resistance, right ventricular hypertrophy, and failure. Pulmonary vascular tone is regulated by a balance between vasoconstrictor and vasodilator mediators, and a shift in this balance to vasoconstriction is an important component of PH pathology, Therefore, the mainstay of current pharmacological therapies centers on pulmonary vasodilation methodologies that either enhance vasodilator mechanisms such as the NO-cGMP and prostacyclin-cAMP pathways and/or inhibit vasoconstrictor mechanisms such as the endothelin-1, cytosolic Ca2+, and Rho-kinase pathways. However, in addition to the increased vascular tone, many patients have a "fixed" component in their disease that involves altered biology of various cells in the pulmonary vascular wall, excessive pulmonary artery remodeling, and perivascular fibrosis and inflammation. Pulmonary arterial smooth muscle cell (PASMC) phenotypic switch from a contractile to a synthetic and proliferative phenotype is an important factor in pulmonary artery remodeling. Although current vasodilator therapies also have some antiproliferative effects on PASMCs, they are not universally successful in halting PH progression and increasing survival. Mild acidification and other novel approaches that aim to reverse the resident pulmonary vascular pathology and structural remodeling and restore a contractile PASMC phenotype could ameliorate vascular remodeling and enhance the responsiveness of PH to vasodilator therapies.

A narrative review of research advances in hypoxic pulmonary hypertension

Background and Objective

Hypoxic pulmonary hypertension (HPH) is a pathological syndrome characterized by pulmonary vasoconstriction and pulmonary vascular remodeling caused by hypoxia, which eventually leads to right heart failure or death. There are 2 stages of onset of HPH: hypoxic pulmonary vasoconstriction (HPV) and hypoxic pulmonary vascular remodeling (HPVR). It is an important pathophysiological link in the pathogenesis of chronic obstructive pulmonary disease (COPD) and chronic mountain sickness (CMS), and its severity is closely related to the course and prognosis of COPD and CMS. However, there is a lack of systematic review on the diagnosis, pathogenesis and treatment of HPH. The objective of this paper is to review the diagnosis, pathogenesis, treatment of HPH.

Methods

In this paper, the method of literature review is adopted to obtain the information about HPH. Based on the literature, comprehensive and systematic review is made. The diagnosis, pathogenesis, treatment of HPH are summarized.

Key Content and Findings

Right heart catheterization is the gold standard for diagnosing HPH. Hypoxia-inducible factor, oxidative stress, metal metabolism, ion channel, inflammatory cytokines, cell apoptosis and vascular factors are the main pathogenesis of HPH. The treatment of HPH includes long-term oxygen therapy, statins, prostaglandins, phosphodiesterase inhibitor and ET receptor antagonists.

Conclusions

Although great progress has been made in the pathophysiology and molecular biology of HPH, it is still unclear which factors play a leading role in the pathogenesis of HPH, and no breakthrough has been made in the treatment of HPH. It is believed that the specific mechanism will be revealed as the research continues, and earlier diagnosis and the development of more effective targeted drugs will be the focus of future research.

Mean Velocity of the Pulmonary Artery as a Clinically Relevant Prognostic Indicator in Patients with Heart Failure with Preserved Ejection Fraction

Background: Right ventricular (RV) to pulmonary circulation (PC) coupling can stratify prognosis in heart failure (HF). In this study, we assessed the prognostic role of the mean velocity of the pulmonary artery (mvPA) determined by cardiac magnetic resonance (CMR) in HF with preserved ejection fraction (HFpEF). Methods: Inclusion of 58 HFpEF outpatients that underwent CMR with measurement of RV–PC coupling parameters including mvPA between 2016 and 2019. The primary combined endpoint was a composite of HF readmissions and all-cause mortality. Results: Optimal cut-off value of mvPA calculated by receiver operating curve for the prediction of the primary endpoint was 9 cm/s. Over a median follow-up of 23 months (interquartile range: 24), 21 patients met the primary endpoint. The primary endpoint was more frequent in patients with mvPA ≤ 9 cm/s, as indicated by Kaplan–Meier survival curves; Log-Rank: 9.193, p = 0.02, regardless of RV dysfunction. On Cox multivariate analysis, mvPA ≤ 9 cm/s emerged as an independent prognostic predictor of the primary endpoint (HR: 4.11, 95% CI: 1.28–13.19, p = 0.017), together with left atrial area by CMR (HR: 1.08, 95% CI: 1.01–1.24, p = 0.034). Conclusions: In our HFpEF cohort, mvPA was associated with a higher rate of the primary endpoint, regardless of RV function, thus enabling identification of patients at higher risk of cardiovascular events before structural damage onset.

A Clinical Approach to Multimodality Imaging in Pulmonary Hypertension

Pulmonary hypertension (PH) is a clinical condition characterized by progressive elevations in mean pulmonary artery pressures and right ventricular dysfunction, associated with significant morbidity and mortality. For resting PH to develop, ~50-70% of the pulmonary vasculature must be affected, suggesting that even mild hemodynamic abnormalities are representative of advanced pulmonary vascular disease. The definitive diagnosis of PH is based upon hemodynamics measured by right heart catheterization; however this is an invasive and resource intense study. Early identification of pulmonary vascular disease offers the opportunity to improve outcomes by instituting therapies that slow, reverse, or potentially prevent this devastating disease. Multimodality imaging, including non-invasive modalities such as echocardiography, computed tomography, ventilation perfusion scans, and cardiac magnetic resonance imaging, has emerged as an integral tool for screening, classifying, prognosticating, and monitoring response to therapy in PH. Additionally, novel imaging modalities such as echocardiographic strain imaging, 3D echocardiography, dual energy CT, FDG-PET, and 4D flow MRI are actively being investigated to assess the severity of right ventricular dysfunction in PH. In this review, we will describe the utility and clinical application of multimodality imaging techniques across PH subtypes as it pertains to screening and monitoring of PH.

Pulmonary vascular resistance and compliance in pulmonary blood flow alterations in children with congenital heart disease

There is a unique hyperbolic relationship between pulmonary vascular resistance (Rp) and compliance (Cp); however, the characteristics of this coupling curve in pulmonary blood flow alterations remains unknown in children with congenital heart disease. We aimed to explore the Rp-Cp coupling and resistant-compliance (RC) time among them. We retrospectively reviewed catheterization data and calculated Rp and Cp in 217 subjects with ventricular septal defect. Median age and weight at catheterization were 2.8 (1.7-4.4) months and 4.3 (3.7-5.3) kg, respectively. Pulmonary hemodynamic parameters were as follows: mean pulmonary arterial pressure: 36 (28-43) mmHg; the amount of pulmonary blood flow (Qp): 14.2 (11.6-17.6) L/min/m²; Rp: 1.95 (1.38-2.59) Wood unit m²; Cp: 2.98 (2.42-3.88) mmHg/mL/m²; and RC time: 0.35 (0.30-0.40) s. RC time remained unchanged according to alterations in Qp (P = 0.206); however, the relationship between logarithm transformations of Rp and Cp showed more steeper according to an increase in Qp. The pulmonary circulation depends upon Cp rather than Rp according to the degree of Qp despite the constancy in RC time. We should take both Rp and Cp into consideration when evaluating the pulmonary circulation among children with congenital heart disease.

Abnormal pulmonary hemodynamics during exercise is associated with exercise capacity in COPD

BACKGROUND

Pulmonary hypertension (PH) is a frequent complication in COPD and it is associated with decreased exercise capacity and poor prognosis. We hypothesized that even in COPD patients without significant PH at rest, abnormal pulmonary hemodynamics during exercise affect exercise capacity.

METHODS

Consecutive COPD patients with clinically indicated right heart catheterization and resting mean pulmonary arterial pressure (mPAP) < 25 mmHg and age- and sex-matched controls with the same limits of pulmonary hemodynamics but no chronic lung disease who underwent clinical work-up including invasive hemodynamic assessment during exercise, were retrospectively analyzed. Chi-square tests were used to evaluate differences between groups for categorical data and Fisher's exact test or Mann-Whitney-U-tests for continuous variables. Associations were analyzed with Spearman rank correlation tests.

RESULTS

We included n = 26 COPD patients (female/male: 16/10, 66 ± 11 yr, FEV₁: 56 ± 25%predicted) and n = 26 matched controls (FEV₁: 96 ± 22%predicted). At rest, COPD patients presented with slightly increased mPAP (21 (18-23) vs. 17 (14-20) mmHg, p = 0.022), and pulmonary vascular resistance (PVR) [2.5 (1.9-3.0) vs. 1.9 (1.5-2.4) WU, p = 0.020] as compared to controls. During exercise, COPD patients reached significantly higher mPAP [47 (40-52) vs. 38 (32-44) mmHg, p = 0.015] and PVR [3.1 (2.2-3.7) vs. 1.7 (1.1-2.9) WU, p = 0.028] values despite lower peak exercise level [50 (50-75) vs. 100 (75-125) Watt, p = 0.002]. The mPAP/cardiac output slope was increased in COPD vs. controls [6.9 (5.5-10.9) vs. 3.7 (2.4-7.4) mmHg/L/min, p = 0.007] and negatively correlated with both peak oxygen uptake (r = - 0.46, p = 0.007) and 6-min walk distance (r = - 0.46, p = 0.001).

CONCLUSION

Even in the absence of significant PH at rest, COPD patients reveal characteristic abnormalities in pulmonary hemodynamics during exercise, which may represent an important exercise-limiting factor.

CMR Measures of Left Atrial Volume Index and Right Ventricular Function Have Prognostic Value in Chronic Thromboembolic Pulmonary Hypertension

Providing prognostic information is important when counseling patients and planning treatment strategies in chronic thromboembolic pulmonary hypertension (CTEPH). The aim of this study was to assess the prognostic value of gold standard imaging of cardiac structure and function using cardiac magnetic resonance imaging (CMR) in CTEPH. Consecutive treatment-naive patients with CTEPH who underwent right heart catheterization and CMR between 2011 and 2017 were identified from the ASPIRE (Assessing-the-Specturm-of-Pulmonary-hypertensIon-at-a-REferral-center) registry. CMR metrics were corrected for age and sex where appropriate. Univariate and multivariate regression models were generated to assess the prognostic ability of CMR metrics in CTEPH. Three hundred and seventy-five patients (mean+/-standard deviation: age 64+/-14 years, 49% female) were identified and 181 (48%) had pulmonary endarterectomy (PEA). For all patients with CTEPH, left-ventricular-stroke-volume-index-%predicted (LVSVI%predicted) (p = 0.040), left-atrial-volume-index (LAVI) (p = 0.030), the presence of comorbidities, incremental shuttle walking test distance (ISWD), mixed venous oxygen saturation and undergoing PEA were independent predictors of mortality at multivariate analysis. In patients undergoing PEA, LAVI (p < 0.010), ISWD and comorbidities and in patients not undergoing surgery, right-ventricular-ejection-fraction-%predicted (RVEF%pred) (p = 0.040), age and ISWD were independent predictors of mortality. CMR metrics reflecting cardiac function and left heart disease have prognostic value in CTEPH. In those undergoing PEA, LAVI predicts outcome whereas in patients not undergoing PEA RVEF%pred predicts outcome. This study highlights the prognostic value of imaging cardiac structure and function in CTEPH and the importance of considering left heart disease in patients considered for PEA.

Comprehensive assessments of pulmonary circulation in children with pulmonary hypertension associated with congenital heart disease

Pulmonary hypertension associated with congenital heart disease (CHD-PH) encompasses different conditions confounded by the left-to-right shunt, left heart obstruction, ventricular dysfunction, hypoxia due to airway obstruction, dysplasia/hypoplasia of the pulmonary vasculature, pulmonary vascular obstructive disease, and genetic variations of vasoactive mediators. Pulmonary input impedance consists of the pulmonary vascular resistance (Rp) and capacitance (Cp). Rp is calculated as the transpulmonary pressure divided by the pulmonary cardiac output, whereas Cp is calculated as the pulmonary stroke volume divided by the pulmonary arterial pulse pressure. The plots of Rp and Cp demonstrate a unique hyperbolic relationship, namely, the resistor-capacitor coupling curve, which represents the pulmonary vascular condition. The product of Rp and Cp is the exponential pressure decay, which refers to the time constant. Alterations in Cp are more considerable in CHD patients at an early stage of developing pulmonary hypertension or with excessive pulmonary blood flow due to a left-to-right shunt. The importance of Cp has gained attention because recent reports have shown that low Cp potentially reflects poor prognosis in patients with CHD-PH and idiopathic pulmonary hypertension. It is also known that Cp levels decrease in specific populations, such as preterm infants and trisomy 21. Therefore, both Rp and Cp should be individually evaluated in the management of children with CHD-PH who have different disease conditions.

Change in pulmonary arterial compliance and pulmonary pulsatile stress after balloon pulmonary angioplasty

OBJECTIVE

Although the underlying pathology of chronic thromboembolic pulmonary hypertension (CTEPH) is mechanical obliteration of the major pulmonary vessels, high pulsatile stress penetrating into the normal distal pulmonary microvasculature resulting from reduced pulmonary arterial compliance (CPA) may cause progressive deterioration in pulmonary hemodynamics. Hypothetically, balloon pulmonary angioplasty (BPA) may be beneficial in reducing CPA and pulsatile stress in patients with CTEPH.

METHODS

In total, 26 patients with available pre- and post-BPA right heart catheterization results were included in the study. BPA was performed in a series of staged procedures by 2 experienced interventional cardiologists.

RESULTS

The median CPA showed a 59.2% increase (1.03 to 1.64 mL/mm Hg, p=0.005). The median pre-BPA pulsatile stress product decreased by 20.7% (4,266 to 3,380 mm Hg/min, p=0.003). A linear regression model established that the percent change in CPA after BPA accounted for 21.8% of the explained variability in the change in 6-minute walk test (p=0.009).

CONCLUSION

Our results indicate that BPA decreases CPA and pulmonary pulsatile stress. These changes may be partly responsible for the improvement in functional capacity after BPA.

The Mechanobiology of Vascular Remodeling in the Aging Lung

Aging is accompanied by declining lung function and increasing susceptibility to lung diseases. The role of endothelial dysfunction and vascular remodeling in these changes is supported by growing evidence, but underlying mechanisms remain elusive. In this review we summarize functional, structural, and molecular changes in the aging pulmonary vasculature and explore how interacting aging and mechanobiological cues may drive progressive vascular remodeling in the lungs.

Topic-Based, Recent Literature Review on Pulmonary Hypertension

Pulmonary hypertension is a complex condition but a relatively common manifestation of severe cardiopulmonary disease. By contrast, pulmonary arterial hypertension is uncommon and is more prevalent in young women. To better categorize patients and to guide clinical decision-making, 5 diagnostic groups and associated subgroups characterize the spectrum of disease. A multidisciplinary approach to evaluation and treatment is recommended by published guidelines and often entails referral to a designated pulmonary hypertension center. Several key publications during the last couple of years merit review. The PubMed database was searched for English-language studies and guidelines relating to pulmonary hypertension. The following terms were searched, alone and in combination: pulmonary hypertension, pulmonary arterial hypertension, portopulmonary hypertension, and chronic thromboembolic pulmonary hypertension. The focus was on those publications with new information on evaluation and management of pulmonary hypertension between January 1, 2019, and January 31, 2021. Of the subgroups, 2 were of particular interest for this review: portopulmonary hypertension and chronic thromboembolic pulmonary hypertension. Last, available data on the impact of the coronavirus disease 2019 pandemic and newer treatment agents in early trials were selectively reviewed. The review is therefore intended to serve as a practical, focused review of important topics germane to those clinicians caring for patients with pulmonary hypertension.

Role of cardiovascular magnetic resonance in pediatric pulmonary hypertension-novel concepts and imaging biomarkers

Pulmonary hypertension (PH) in children is a heterogenous disease of the small pulmonary arteries characterized by a progressive increase in pulmonary vascular resistance. Despite adequate medical therapy, long-term pressure overload is frequently associated with a progressive course leading to right ventricular failure and ultimately death. Invasive hemodynamic assessment by cardiac catheterization is crucial for initial diagnosis, risk stratification and therapeutic strategy. Although echocardiography remains the most important imaging modality for the assessment of right ventricular function and pulmonary hemodynamics, cardiovascular magnetic resonance (CMR) has emerged as a valuable non-invasive imaging technique that enables comprehensive evaluation of biventricular performance, blood flow, morphology and the myocardial tissue. In this review, we summarize the principles and applications of CMR in the evaluation of pediatric PH patients and present an update about novel CMR based concepts and imaging biomarkers that may provide further diagnostic, therapeutic and prognostic information.

Spironolactone Reduces Aortic Stiffness in Patients With Resistant Hypertension Independent of Blood Pressure Change

Background

Aortic stiffness is an independent predictor of cardiovascular events in patients with arterial hypertension. Resistant hypertension is often linked to hyperaldosteronism and associated with adverse outcomes. Spironolactone, a mineralocorticoid receptor antagonist, has been shown to reduce both the arterial blood pressure (BP) and aortic stiffness in resistant hypertension. However, the mechanism of aortic stiffness reduction by spironolactone is not well understood. We hypothesized that spironolactone reduces aortic stiffness in resistant hypertension independently of BP change.

Methods and Results

Patients with uncontrolled BP (≥140/90 mm Hg) despite use of ≥3 antihypertensive medications (including diuretics) were prospectively recruited. Participants were started on spironolactone at 25 mg/d, and increased to 50 mg/d at 4 weeks while other antihypertensive medications were withdrawn to maintain constant mean BP. Phase‐contrast cardiac magnetic resonance imaging of the ascending aorta was performed in 30 participants at baseline and after 6 months of spironolactone treatment to measure aortic pulsatility, distensibility, and pulse wave velocity. Pulse wave velocity decreased (6.3±2.3 m/s to 4.5±1.8 m/s, P<0.001) and pulsatility and distensibility increased (15.9%±5.3% to 22.1%±7.9%, P<0.001; and 0.28%±0.10%/mm Hg to 0.40%±0.14%/mm Hg, P<0.001, respectively) following 6 months of spironolactone.

Conclusions

Our results suggest that spironolactone improves aortic properties in resistant hypertension independently of BP, which may support the hypothesis of an effect of aldosterone on the arterial wall. A larger prospective study is needed to confirm our findings.

CTA pulmonary artery enlargement in patients with severe aortic stenosis: Prognostic impact after TAVR

BACKGROUND

Identifying high-risk patients who will not derive substantial survival benefit from TAVR remains challenging. Pulmonary hypertension is a known predictor of poor outcome in patients undergoing TAVR and correlates strongly with pulmonary artery (PA) enlargement on CTA. We sought to evaluate whether PA enlargement, measured on pre-procedural computed tomography angiography (CTA), is associated with 1-year mortality in patients undergoing TAVR.

METHODS

We retrospectively included 402 patients undergoing TAVR between July 2012 and March 2016. Clinical parameters, including Society of Thoracic Surgeons (STS) score and right ventricular systolic pressure (RVSP) estimated by transthoracic echocardiography were reviewed. PA dimensions were measured on pre-procedural CTAs. Association between PA enlargement and 1-year mortality was analyzed. Kaplan-Meier and Cox proportional hazards regression analyses were performed.

RESULTS

The median follow-up time was 433 (interquartiles 339-797) days. A total of 56/402 (14%) patients died within 1 year after TAVR. Main PA area (area-MPA) was independently associated with 1-year mortality (hazard ratio per standard deviation equal to 2.04 [95%-confidence interval (CI) 1.48-2.76], p ​< ​0.001). Area under the curve (95%-CI) of the clinical multivariable model including STS-score and RVSP increased slightly from 0.67 (0.59-0.75) to 0.72 (0.72-0.89), p ​= ​0.346 by adding area-MPA. Although the AUC increased, differences were not significant (p ​= ​0.346). Kaplan-Meier analysis showed that mortality was significantly higher in patients with a pre-procedural non-indexed area-MPA of ≥7.40 ​cm² compared to patients with a smaller area-MPA (mortality 23% vs. 9%; p ​< ​0.001).

CONCLUSIONS

Enlargement of MPA on pre-procedural CTA is independently associated with 1-year mortality after TAVR.

Effect of pulsatile stretch on unfolded protein response in a new model of the pulmonary hypertensive vascular wall

Persistent pulmonary hypertension of the newborn (PPHN) is characterized by hypoxemia and arterial remodeling. Dynamic stretch and recoil of the arterial wall during pulsation (in normal conduit arteries, stretch 20% above diastolic diameter) maintains homeostasis; a static arterial wall is associated with remodeling. PPHN is diagnosed by echocardiography as decreased pulmonary artery wall displacement during systole, causing decreased pulmonary arterial pressure acceleration time in a stiff artery.

We hypothesized that a ‘normal’ amplitude of pulsatile stretch is protective against ER stress, while the loss of stretch is a trigger for hypoxia-induced stress responses. Using a novel in vitro model of pulmonary arterial myocytes subject to repetitive stretch-relaxation cycles within a normoxic or hypoxic environment, we examined the relative impact of hypoxia (pulmonary circuit during unresolved PPHN) and cyclic mechanical stretch (diminished in PPHN) on myocyte homeostasis, specifically on signaling proteins for autophagy and endoplasmic reticulum (ER) stress.

Stretch induced autophagosome abundance under electron microscopy. Hypoxia, in presence or absence of pulsatile stretch, decreased unfolded protein response (UPR) hallmark BIP (GRP78) in contractile phenotype pulmonary arterial myocytes. Inositol requiring enzyme-1 α (IRE1α) was not activated; but hypoxia induced eif2α phosphorylation, increasing expression of ATF4 (activating transcription factor-4). This was sensitive to inhibition by autophagy inhibitor bafilomycin A1.

We conclude that in the pulmonary circuit, hypoxia induces one arm of the UPR pathway and causes ER stress. Pulsatile stretch ameliorates the hypoxic UPR response, and while increasing presence of autophagosomes, does not activate canonical autophagy signaling pathways. We propose that simultaneous application of hypoxia and graded levels of cyclic stretch can be used to distinguish myocyte signaling in the deformable pulmonary artery of early PPHN, versus the inflexible late stage PPHN artery.

[Possibilities of Magnetic Resonance Tomography in Diagnosis of Pulmonary Arterial Hypertension]

The emergence of more effective methods for treatment of pulmonary arterial hypertension (PAH) has called for more reliable methods of diagnostics, monitoring, and evaluating responses to the treatment. More reports have become available about the relevance of using magnetic resonance imaging (MRI) for examination of patients with PAH. This review provides data on the significance of MRI for noninvasive evaluation of the heart structure and function in patients with PAH, as well as for visualization and evaluation of the remodeling of the pulmonary circulation. According to the data presented in this review, the results obtained with various, modern MRI technologies can be used for monitoring the effect of treatment and for risk stratification in patients with PAH.

Invasive Hemodynamics in Heart Failure with Preserved Ejection Fraction: Importance of Detecting Pulmonary Vascular Remodeling and Right Heart Function

Heart failure (HF) is an ongoing crisis reaching epidemic proportions worldwide. About 50% of HF patients have a preserved ejection fraction. Invasive hemodynamics have shown varied results in patients who have HF with preserved ejection fraction (HFpEF). This article attempts to summarize the importance of detecting pulmonary vascular remodeling in HFpEF using invasive hemodynamics. Incorporating newer invasive hemodynamic parameters such as diastolic pulmonary gradient, pulmonary arterial compliance, pulmonary vascular resistance, and pulmonary arterial pulsatility index may improve patient selection for studies used in defining advanced therapies and clinical outcomes. Profiling of patients using invasive hemodynamic parameters may lead to better patient selection for clinical research.

Carbonic anhydrase inhibition improves pulmonary artery reactivity and nitric oxide-mediated relaxation in sugen-hypoxia model of pulmonary hypertension

Pulmonary hypertension (PH) is a serious disease with pulmonary arterial fibrotic remodeling and limited responsiveness to vasodilators. Our data suggest that mild acidosis induced by carbonic anhydrase inhibition could ameliorate PH, but the vascular mechanisms are unclear. We tested the hypothesis that carbonic anhydrase inhibition ameliorates PH by improving pulmonary vascular reactivity and relaxation mechanisms. Male Sprague-Dawley rats were either control normoxic (Nx), or injected with Sugen 5416 (20 mg/kg, sc) and subjected to hypoxia (9% O2) (Su + Hx), or Su + Hx treated with acetazolamide (ACTZ, 100 mg/kg/day, in drinking water). After measuring the hemodynamics, right ventricular hypertrophy was assessed by Fulton's Index; vascular function was measured in pulmonary artery, aorta, and mesenteric arteries; and pulmonary arteriolar remodeling was assessed in lung sections. Right ventricular systolic pressure and Fulton's Index were increased in Su + Hx and reduced in Su + Hx + ACTZ rats. Pulmonary artery contraction to KCl and phenylephrine were reduced in Su + Hx and improved in Su + Hx + ACTZ. Acetylcholine (ACh)-induced relaxation and nitrate/nitrite production were reduced in pulmonary artery of Su + Hx and improved in Su + Hx + ACTZ. ACh relaxation was blocked by nitric oxide (NO) synthase and guanylate cyclase inhibitors, supporting a role of NO-cGMP. Sodium nitroprusside (SNP)-induced relaxation was reduced in pulmonary artery of Su + Hx, and ACTZ enhanced relaxation to SNP. Contraction/relaxation were not different in aorta or mesenteric arteries of all groups. Pulmonary arterioles showed wall thickening in Su + Hx that was ameliorated in Su + Hx + ACTZ. Thus, amelioration of pulmonary hemodynamics during carbonic anhydrase inhibition involves improved pulmonary artery reactivity and NO-mediated relaxation and may enhance responsiveness to vasodilator therapies in PH.

The isobaric pulmonary arterial compliance in pulmonary hypertension

Pulmonary hypertension is associated with stiffening of pulmonary arteries which increases right ventricular pulsatile loading. High pulmonary artery wedge pressure (PAWP) in postcapillary pulmonary hypertension (Pc-PH) further decreases pulmonary arterial compliance (PAC) at a given pulmonary vascular resistance (PVR) compared with precapillary pulmonary hypertension, thus responsible for a higher total arterial load. In all other vascular beds, arterial compliance is considered as mainly determined by the distending pressure, due to non-linear stress-strain behaviour of arteries. We tested the applicability, advantages and drawbacks of two comparison methods of PAC depending on the level of mean pulmonary arterial pressure (mPAP; isobaric PAC) or PVR.

Right heart catheterisation data including PAC (stroke volume/pulse pressure) were obtained in 112 Pc-PH (of whom 61 had combined postcapillary and precapillary pulmonary hypertension) and 719 idiopathic pulmonary arterial hypertension (iPAH).

PAC could be compared over the same mPAP range (25–66 mmHg) in 792 (95.3%) out of 831 patients and over the same PVR range (3–10.7 WU) in only 520 (62.6%) out of 831 patients. The main assumption underlying comparisons at a given PVR was not verified as the PVR×PAC product (RC-time) was not constant but on the contrary more variable than mPAP. In the 788/831 (94.8%) patients studied over the same PAC range (0.62–6.5 mL·mmHg⁻¹), PVR and thus total arterial load tended to be higher in iPAH.

Our study favours comparing PAC at fixed mPAP level (isobaric PAC) rather than at fixed PVR. A reappraisal of the effects of PAWP on the pulsatile and total arterial load put on the right heart is needed, and this point deserves further studies.

In postcapillary and precapillary pulmonary hypertension patients, this study favours comparing pulmonary arterial compliance (PAC) at fixed mean pulmonary artery pressure level (isobaric PAC) rather than at fixed pulmonary vascular resistance levelhttps://bit.ly/3aTLYdS

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.

Pulmonary Arterial Remodeling Is Related to the Risk Stratification and Right Ventricular-Pulmonary Arterial Coupling in Patients With Pulmonary Arterial Hypertension

Background

Pulmonary arterial (PA) stiffness has an essential contribution to the right ventricular (RV) failure pathogenesis. A comprehensive and multiparameter risk assessment allows predicting mortality and guiding treatment decisions in PA hypertension (PAH). We characterize PA remodeling with intravascular ultrasound (IVUS) in prevalent and stable patients with PAH according to the ESC/ERS risk table and analyze the RV-PA coupling consequences.

Methods

Ten control subjects and 20 prevalent PAH adult patients underwent right heart catheterization (RHC) with simultaneous IVUS study. We estimated cardiac index (CI), pulmonary vascular resistance, and compliance (PVR, PAC) by standard formulas. From IVUS and RHC data, PA diameter, wall thickness/luminal diameter ratio, and indexes of stiffness (pulsatility, compliance, distensibility, incremental elastic modulus - Einc-, and the stiffness index β) were measured. We evaluated RV-PA coupling by the ratio of tricuspid annular plane systolic excursion to systolic pulmonary arterial pressure (TAPSE/sPAP). The individual average risk was calculated by assigning a score of 1 (low-risk -LR-), 2 (intermediate-risk -IR-), and 3 (high-risk -HR-) for each of seven variables (functional class, six-minute walking test, brain natriuretic peptide, right atrial area and pressure, CI, and PA oxygen saturation) and rounding the average value to the nearest integer.

Results

All PA segments interrogated showed increased vessel diameter, wall cross-sectional area (WCSA), and stiffness in patients with PAH compared to control subjects. 45% corresponded to LR, and 55% corresponded to IR PAH patients. The different measurements of PA stiffness showed significant correlations with TAPSE/sPAP (r = 0.6 to 0.76) in PAH patients. The IR group had higher PA stiffness and lower relative WCSA than LR patients (P < 0.05), and it is associated with a lower PAC and TAPSE/sPAP (P < 0.05).

Conclusion

In prevalent PAH patients, the severity of proximal PA remodeling is related to the risk stratification and associated with PAC and RV-PA coupling impairment beyond the indirect effect of the mean PA pressure. The concomitant assessment of IVUS and hemodynamic parameters at diagnosis and follow-up of PAH patients could be a feasible and safe tool for risk stratification and treatment response of the PA vasculopathy during serial hemodynamic measurements.

Potential damage in pulmonary arterial hypertension: An experimental study of pressure-induced damage of pulmonary artery

Pulmonary arterial hypertension (PAH) is associated with elevated pulmonary arterial pressure. PAH prognosis remains poor with a 15% mortality rate within 1 year, even with modern clinical management. Previous clinical studies proposed wall shear stress (WSS) to be an important hemodynamic factor affecting cell mechanotransduction, growth and remodeling, and disease progress in PAH. However, WSS in vivo is typically at most 2.5 Pa and a doubt has been cast whether WSS alone can drive disease progress. Furthermore, our current understanding of PAH pathology largely comes from small animals' studies in which caliber enlargement, a hallmark of PAH in humans, is rarely reported. Therefore, a large-animal experiment on pulmonary arteries (PAs) is needed to validate whether increased pressure can induce enlargement of PAs caliber. In this study, we use an inflation testing device to characterize the mechanical behavior, both nonlinear elastic behavior and irreversible damage of porcine arteries. The parameters of elastic behavior are estimated from the inflation test at a low-pressure range before and after over-pressurization. Then, histological images are qualitatively examined for medial and adventitial layers. This study sheds light on the relevance of pressure-induced damage mechanism in human PAH.