Validation of the Tricuspid Annular Plane Systolic Excursion/Systolic Pulmonary Artery Pressure Ratio for the Assessment of Right Ventricular-Arterial Coupling in Severe Pulmonary Hypertension

Right Heart Phenotype in Heart Failure With Preserved Ejection Fraction

The health burden of heart failure with preserved ejection fraction is increasingly recognized. Despite improvements in diagnostic algorithms and established knowledge on the clinical trajectory, effective treatment options for heart failure with preserved ejection fraction remain limited, mainly because of the high mechanistic heterogeneity. Diagnostic scores, big data, and phenomapping categorization are proposed as key steps needed for progress. In the meantime, advancements in imaging techniques combined to high-fidelity pressure signaling analysis have uncovered right ventricular dysfunction as a mediator of heart failure with preserved ejection fraction progression and as major independent determinant of poor outcome. This review summarizes the current understanding of the pathophysiology of right ventricular dysfunction in heart failure with preserved ejection fraction covering the different right heart phenotypes and offering perspectives on new treatments targeting the right ventricle in its function and geometry.

Feasibility of semi-recumbent bicycle exercise Doppler echocardiography for the evaluation of the right heart and pulmonary circulation unit in different clinical conditions: the RIGHT heart international NETwork (RIGHT-NET)

Exercise Doppler echocardiography (EDE) is a well-validated tool in ischemic and valvular heart diseases. However, its use in the assessment of the right heart and pulmonary circulation unit (RH-PCU) is limited. The aim of this study is to assess the semi-recumbent bicycle EDE feasibility for the evaluation of RH-PCU in a large multi-center population, from healthy individuals and elite athletes to patients with overt or at risk of developing pulmonary hypertension (PH). From January 2019 to July 2019, 954 subjects [mean age 54.2 ± 16.4 years, range 16-96, 430 women] underwent standardized semi-recumbent bicycle EDE with an incremental workload of 25 watts every 2 min, were prospectively enrolled among 7 centers participating to the RIGHT Heart International NETwork (RIGHT-NET). EDE parameters of right heart structure, function and pressures were obtained according to current recommendations. Right ventricular (RV) function at peak exercise was feasible in 903/940 (96%) by tricuspid annular plane systolic excursion (TAPSE), 667/751 (89%) by tissue Doppler-derived tricuspid lateral annular systolic velocity (S') and 445/672 (66.2%) by right ventricular fractional area change (RVFAC). RV-right atrial pressure gradient [RV-RA gradient = 4 × tricuspid regurgitation velocity² (TRV)] was feasible in 894/954 patients (93.7%) at rest and in 816/954 (85.5%) at peak exercise. The feasibility rate in estimating pulmonary artery pressure improved to more than 95%, if both TRV and/or right ventricular outflow tract acceleration time (RVOT AcT) were considered. In high specialized echocardiography laboratories semi-recumbent bicycle EDE is a feasible tool for the assessment of the RH-PCU pressure and function.

Interferon-β-Induced Pulmonary Arterial Hypertension: Approach to Diagnosis and Clinical Monitoring

A 48-year-old woman who had been receiving long-term interferon-β for 8 years for multiple sclerosis developed drug-induced World Health Organization group I pulmonary arterial hypertension. Triple therapy for pulmonary arterial hypertension and suspension of interferon-β led to improvement from a high-risk to low-risk state and improvement in exercise hemodynamics, including vascular distensibility, and right ventricle–pulmonary artery coupling. (Level of Difficulty: Advanced.)

Pulmonary haemodynamic response to exercise in highlanders versus lowlanders

The aim of the study was to investigate the pulmonary haemodynamic response to exercise in Central Asian high- and lowlanders.

This was a cross-sectional study in Central Asian highlanders (living >2500 m) compared with lowlanders (living <800 m), assessing cardiac function, including tricuspid regurgitation pressure gradient (TRPG), cardiac index and tricuspid annular plane systolic excursion (TAPSE) by echocardiography combined with heart rate and oxygen saturation measured by pulse oximetry (S_pO2) during submaximal stepwise cycle exercise (10 W increase per 3 min) at their altitude of residence (at 760 m or 3250 m, respectively).

52 highlanders (26 females; aged 47.9±10.7 years; body mass index (BMI) 26.7±4.6 kg·m⁻²; heart rate 75±11 beats·min⁻¹; S_pO2 91±5%;) and 22 lowlanders (eight females; age 42.3±8.0 years; BMI 26.9±4.1 kg·m⁻²; heart rate 68±7 beats·min⁻¹; S_pO2 96±1%) were studied. Highlanders had a lower resting S_pO2 compared to lowlanders but change during exercise was similar between groups (highlanders versus lowlanders −1.4±2.9% versus −0.4±1.1%, respectively, p=0.133). Highlanders had a significantly elevated TRPG and exercise-induced increase was significantly higher (13.6±10.5 mmHg versus 6.1±4.8 mmHg, difference 7.5 (2.8 to 12.2) mmHg; p=0.002), whereas cardiac index increase was slightly lower in highlanders (2.02±0.89 L·min⁻¹versus 1.78±0.61 L·min⁻¹, difference 0.24 (−0.13 to 0.61) L·min⁻¹; p=0.206) resulting in a significantly steeper pressure–flow ratio (ΔTRPG/Δcardiac index) in highlanders 9.4±11.4 WU and lowlanders 3.0±2.4 WU (difference 6.4 (1.4 to 11.3) WU; p=0.012). Right ventricular-arterial coupling (TAPSE/TRPG) was significantly lower in highlanders but no significant difference in change with exercise in between groups was detected (−0.01 (−0.20 to 0.18); p=0.901).

In highlanders, chronic exposure to hypoxia leads to higher pulmonary artery pressure and a steeper pressure–flow relation during exercise.

Central Asian highlanders living between 2500 and 3600 m assessed by stress echocardiography showed that chronic exposure to hypoxia leads to a steeper pressure–flow curve during exercise and worse right ventricular–arterial coupling compared to lowlandershttps://bit.ly/3qlvhOj

Prognostic value and reversibility of liver stiffness in patients undergoing tricuspid annuloplasty

BACKGROUND

Liver stiffness (LS) assessed by transient elastography is associated with adverse events in patients with heart failure. However, the predictive value of LS for adverse outcome is uncertain in patients undergoing tricuspid annuloplasty (TA). This study sought to evaluate the prognostic value and reversibility of LS in patients undergoing TA during left-sided valve surgery.

METHODS AND RESULTS

A total of 158 patients who underwent TA were prospectively evaluated. Patients were divided into three groups according to tertile of LS. Adverse outcome was defined as heart failure that required hospital admission or all-cause mortality following TA. The median LS was 13.9 (inter-quartile range 8.1-22.3) kPa and independently correlated positively with tricuspid regurgitation (TR) severity, inferior vena cava diameter and negatively with tricuspid annular plane systolic excursion. During a median follow-up of 31 months, 49 adverse events occurred. Multivariable Cox regression analysis revealed that LS was an independent predictor of adverse events. Significant improvement in LS at 1-year post-TA (13.1-7.8 kPa, P < 0.01) was noted only in patients who had no adverse events, not in those who experienced heart failure (17.1-14.2 kPa, P = 0.87) and seems to be linked to an absence of TR recurrence.

CONCLUSIONS

This study demonstrated that LS is predictive of adverse outcome and is reversible in patients undergoing TA without TR recurrence at 1 year. These findings suggest that assessing LS, an integrative correlate of right heart condition, may aid the pre-operative risk assessment of candidate for heart surgery including TA.

Validity of echocardiographic tricuspid regurgitation gradient to screen for new definition of pulmonary hypertension

BACKGROUND

Currently an echocardiographic threshold for the tricuspid regurgitation gradient (TRG) of > 31 mmHg is recommended for screening for pulmonary hypertension (PH). Invasively diagnosed PH was recently redefined as mean pulmonary arterial pressure (mPAP) > 20 mmHg instead of ≥ 25 mmHg. We investigated the ability of TRG to screen for the new PH-definition.

METHODS

Retrospective assessment of echocardiography and right heart catheterisation data from 1572 patients entering the Giessen PH-Registry during 2008-2018. Accuracy of different TRG thresholds and other echocardiographic parameters was evaluated using receiver operating characteristic curves.

FINDINGS

1264 patients fulfilled the new PH-definition. Positive (PPV) and negative predictive values and accuracy of TRG > 46 mmHg were 95%, 39%, and 73%, respectively, for the new PH-definition. Lowering the TRG cut-off to 31 mmHg and below worsened PPV to ≤ 89%. The PPV of TRG for pre-capillary PH (mPAP > 20 mmHg and pulmonary vascular resistance ≥ 3 Wood Units) was ≤ 85%. In patients with TRG ≤ 46 mmHg, tricuspid annular plane systolic excursion/TRG and TRG/right ventricular outflow tract acceleration time were superior to TRG in screening for newly defined pre-capillary PH.

INTERPRETATION

In patients with suspected PH referred to a tertiary care centre, the PPV of TRG to meet the new PH-definition depended strongly on the TRG cut-off used. Our data do not support lowering the TRG cut-off. Combining TRG with other echocardiographic parameters might improve the validity of echocardiographic screening for PH.

Right Ventricular Pulmonary Artery Coupling and Mortality in Cardiac Intensive Care Unit Patients

Background

Impaired right ventricular (RV) pulmonary artery coupling has been associated with higher mortality in patients with chronic heart disease, but few studies have examined this metric in critically ill patients. We sought to evaluate the association between RV pulmonary artery coupling, defined by the ratio of tricuspid annular peak systolic tissue Doppler velocity (TASV)/estimated RV systolic pressure (RVSP), and mortality in cardiac intensive care unit patients.

Methods and Results

Using a database of unique cardiac intensive care unit admissions from 2007 to 2018, we included patients with TASV/RVSP ratio measured within 1 day of hospitalization. Hospital mortality was analyzed using multivariable logistic regression, and 1‐year mortality was analyzed using multivariable Cox proportional‐hazards analysis. We included 4259 patients with a mean age of 69±15 years (40.1% women). Admission diagnoses included acute coronary syndrome in 56%, heart failure in 52%, respiratory failure in 24%, and cardiogenic shock in 12%. The mean TASV/RVSP ratio was 0.31±0.14, and in‐hospital mortality occurred in 7% of patients. Higher TASV/RVSP ratio was associated with lower in‐hospital mortality (adjusted unit odds ratio, 0.68 per each 0.1‐unit higher ratio; 95% CI, 0.58–0.79; P<0.001) and lower 1‐year mortality among hospital survivors (adjusted unit hazard ratio, 0.83 per each 0.1‐unit higher ratio; 95% CI, 0.77–0.90; P<0.001). Stepwise decreases in hospital and 1‐year mortality were observed in each higher TASV/RVSP quintile. The TASV/RVSP ratio remained associated with mortality after adjusting for left ventricular systolic and diastolic function.

Conclusions

A low TASV/RVSP ratio is associated with increased short‐term and long‐term mortality among cardiac intensive care unit patients, emphasizing importance of impaired RV pulmonary artery coupling as a determinant of poor prognosis. Further study is required to determine whether interventions to optimize RV pulmonary artery coupling can improve outcomes.

Extravascular lung water and cardiac function assessed by echocardiography in healthy lowlanders during repeated very high-altitude exposure

BACKGROUND

High-altitude pulmonary edema is associated with elevated systolic pulmonary artery pressure (sPAP) and increased extravascular lung water (EVLW). We investigated sPAP and EVLW during repeated exposures to high altitude (HA).

METHODS

Healthy lowlanders underwent two identical 7-day HA-cycles, where subjects slept at 2900 m and spent 4-8 h daily at 5050 m, separated by a weeklong break at low altitude (LA). Echocardiography and EVLW by B-lines were measured at 520 m (baseline, LA₁), on day one, two and six at 5050 m (HA_1-3) and after descent (LA₂).

RESULTS

We included 21 subjects (median 25 years, body mass index 22 kg/m², SpO₂ 98%). SPAP rose from 21 mmHg at LA₁ to 38 mmHg at HA₁, decreased to 30 mmHg at HA₃ (both p < 0.05 vs LA₁) and normalized at 20 mmHg at LA₂ (p = ns vs LA₁). B-lines increased from 0 at LA₁ to 6 at HA₂ and 7 at HA₃ (both p < 0.05 vs LA₁) and receded to 1 at LA₂ (p = ns vs LA₁). Overall, in cycle two, sPAP did not differ (mean difference (95% confidence interval) -0.2(-2.3 to 1.9) mmHg, p = 0.864) but B-lines were more prevalent (+2.3 (1.4-3.1), p < 0.001) compared to cycle 1. Right ventricular systolic function decreased significantly but minimally at 5050 m.

CONCLUSIONS

Exposure to 5050 m induced a rapid increase in sPAP. B-lines rose during prolonged exposures to 5050 m, despite gradual decrease in sPAP, indicating excessive hydrostatic pressure might not be solely responsible for EVLW-development. Repeated HA-exposure had no acclimatization effect on EVLW. This may affect workers needing repetitive ascents to altitude and could indicate greater B-line development upon repeated exposure.

Impact of COVID-19 on exercise pathophysiology: a combined cardiopulmonary and echocardiographic exercise study

Survivors from COVID-19 pneumonia can present with persisting multisystem involvement (lung, pulmonary vessels, heart, muscle, red blood cells) that may negatively affect exercise capacity. We sought to determine the extent and the determinants of exercise limitation in patients with COVID-19 at the time of hospital discharge. Eighteen consecutive patients with COVID-19 and 1:1 age-, sex-, and body mass index-matched controls underwent: spirometry, echocardiography, cardiopulmonary exercise test and exercise echocardiography for the study of pulmonary circulation. Arterial blood was sampled at rest and during exercise in patients with COVID-19. Patients with COVID-19 lie roughly on the same oxygen consumption isophlets than controls both at rest and during submaximal exercise, thanks to supernormal cardiac output (P < 0.05). Oxygen consumption at peak exercise was reduced by 30% in COVID-19 (P < 0.001), due to a peripheral extraction limit. In addition, within COVID-19 patients, hemoglobin content was associated with peak oxygen consumption (R² = 0.46, P = 0.002). Respiratory reserve was not exhausted (median [IRQ], 0.59 [0.15]) in spite of moderate reduction of forced vital capacity (79 ± 40%). Pulmonary artery pressure increase during exercise was not different between patients and controls. Ventilatory equivalents for carbon dioxide were higher in patients with COVID-19 than in controls (39.5 [8.5] vs. 29.5 [8.8], P < 0.001), and such an increase was mainly explained by increased chemosensitivity. When recovering from COVID-19, patients present with reduced exercise capacity and augmented exercise hyperventilation. Peripheral factors, including anemia and reduced oxygen extraction by peripheral muscles were the major determinants of deranged exercise physiology. Pulmonary vascular function seemed unaffected, despite restrictive lung changes.NEW & NOTEWORTHY At the time of hospital discharge, patients with COVID-19 present with reduced functional capacity and exercise hyperventilation. Peripheral factors, namely reduced oxygen extraction (myopathy) and anemia, which are not fully compensated by a supernormal cardiac output response, account for exercise limitation before exhaustion of the respiratory reserve. Enhanced chemoreflex sensitivity, rather increased dead space, mainly accounts for exercise hyperventilation. The pulmonary vascular response to exercise circulation of survived patients with COVID-19 does not present major pathological changes.

Right ventricular pressure-volume loop shape and systolic pressure change in pulmonary hypertension

Right ventricular (RV) function determines outcome in pulmonary arterial hypertension (PAH). RV pressure-volume loops, the gold standard for measuring RV function, are difficult to analyze. Our aim was to investigate whether simple assessments of RV pressure-volume loop morphology and RV systolic pressure differential reflect PAH severity and RV function. We analyzed multibeat RV pressure-volume loops (obtained by conductance catheterization with preload reduction) in 77 patients with PAH and 15 patients without pulmonary hypertension in two centers. Patients were categorized according to their pressure-volume loop shape (triangular, quadratic, trapezoid, or notched). RV systolic pressure differential was defined as end-systolic minus beginning-systolic pressure (ESP - BSP), augmentation index as ESP - BSP/pulse pressure, pulmonary arterial capacitance (PAC) as stroke volume/pulse pressure, and RV-arterial coupling as end-systolic/arterial elastance (Ees/Ea). Trapezoid and notched pressure-volume loops were associated with the highest afterload (Ea), augmentation index, pulmonary vascular resistance (PVR), mean pulmonary arterial pressure, stroke work, B-type natriuretic peptide, and the lowest Ees/Ea and PAC. Multivariate linear regression identified Ea, PVR, and stroke work as the main determinants of ESP - BSP. ESP - BSP also significantly correlated with multibeat Ees/Ea (Spearman's ρ: -0.518, P < 0.001). A separate retrospective analysis of 113 patients with PAH showed that ESP - BSP obtained by routine right heart catheterization significantly correlated with a noninvasive surrogate of RV-arterial coupling (tricuspid annular plane systolic excursion/pulmonary arterial systolic pressure ratio; ρ: -0.376, P < 0.001). In conclusion, pressure-volume loop shape and RV systolic pressure differential predominately depend on afterload and PAH severity and reflect RV-arterial coupling in PAH.

Prognostic Role of TAPSE to PASP Ratio in Patients Undergoing MitraClip Procedure

Background: Transcatheter mitral valve repair (TMVR) is an effective therapy for high-risk patients with severe mitral regurgitation (MR) but heart failure (HF) readmissions and death remain substantial on mid-term follow-up. Recently, right ventricular (RV) to pulmonary arterial (PA) coupling has emerged as a relevant prognostic predictor in HF. In this study, we aimed to assess the prognostic value of tricuspid annular plane systolic excursion (TAPSE) to PA systolic pressure (PASP) ratio as a non-invasive measure of RV-to-PA coupling in patients undergoing TMVR with MitraClip (Abbott, CA, USA). Methods: Multicentre registry including 228 consecutive patients that underwent successful TMVR with MitraClip. The sample was divided in two groups according to TAPSE/PASP median value: 0.35. The primary combined endpoint encompassed HF readmissions and all-cause mortality. Results: Mean age was 72.5 ± 11.5 years and 154 (67.5%) patients were male. HF readmissions and all-cause mortality were more frequent in patients with TAPSE/PASP ≤ 0.35: Log-Rank 8.844, p = 0.003. On Cox regression, TAPSE/PASP emerged as a prognostic predictor of the primary combined endpoint, together with STS-Score. TAPSE/PASP was a better prognostic predictor than either TAPSE or PASP separately. Conclusions: TAPSE/PASP ratio appears as a novel prognostic predictor in patients undergoing MitraClip implantation that might improve risk stratification and candidate selection.

A novel non-invasive and echocardiography-derived method for quantification of right ventricular pressure-volume loops

AIMS

We sought to assess the feasibility of constructing right ventricular (RV) pressure-volume (PV) loops solely by echocardiography.

METHODS AND RESULTS

We performed RV conductance and pressure wire (PW) catheterization with simultaneous echocardiography in 35 patients with pulmonary hypertension. To generate echocardiographic PV loops, a reference RV pressure curve was constructed using pooled PW data from the first 20 patients (initial cohort). Individual pressure curves were then generated by adjusting the reference curve according to RV isovolumic and ejection phase duration and estimated RV systolic pressure. The pressure curves were synchronized with echocardiographic volume curves. We validated the reference curve in the remaining 15 patients (validation cohort). Methods were compared with correlation and Bland-Altman analysis. In the initial cohort, echocardiographic and conductance-derived PV loop parameters were significantly correlated {rho = 0.8053 [end-systolic elastance (Ees)], 0.8261 [Ees/arterial elastance (Ea)], and 0.697 (stroke work); all P < 0.001}, with low bias [-0.016 mmHg/mL (Ees), 0.1225 (Ees/Ea), and -39.0 mmHg mL (stroke work)] and acceptable limits of agreement. Echocardiographic and PW-derived Ees were also tightly correlated, with low bias (-0.009 mmHg/mL) and small limits of agreement. Echocardiographic and conductance-derived Ees, Ees/Ea, and stroke work were also tightly correlated in the validation cohort (rho = 0.9014, 0.9812, and 0.9491, respectively; all P < 0.001), with low bias (0.0173 mmHg/mL, 0.0153, and 255.1 mmHg mL, respectively) and acceptable limits.

CONCLUSION

The novel echocardiographic method is an acceptable alternative to invasively measured PV loops to assess contractility, RV-arterial coupling, and RV myocardial work. Further validation is warranted.

The Growing Role of Echocardiography in Pulmonary Arterial Hypertension Risk Stratification: The Missing Piece

Pulmonary arterial hypertension (PAH) is a rare, progressive disease with a poor prognosis. The pathophysiologic model is mainly characterized by an afterload mismatch in which an increased right ventricle afterload, driven by increased pulmonary vascular resistance (PVR), leads to right heart failure. International guidelines recommend optimization of treatment based on regular risk assessments to achieve or maintain a low-risk status. Current risk scores are based on a multi-modality approach, including demographic, clinical, functional, exercise, laboratory, and hemodynamic parameters, which lack significant echocardiographic parameters. The originality of echocardiography relies on the opportunity to assess in a non-invasive way a physiologically meaningful combination of easy to measure variables tightly related to right ventricle adaptation/maladaptation to increased afterload, the main determinant of a patient's prognosis. Echo-derived morphological and functional parameters have been investigated in PAH, proving to have prognostic relevance. Different therapeutic strategies proved to have different effects in reducing PVR. An upfront combination of drugs, including a parenteral prostacyclin, has shown to be associated with right heart reverse remodeling in a greater proportion of patients than other treatment strategies as a function of PVR reduction. Adding echocardiographic data to current risk scores would allow better identification of right ventricle (RV) adaptation in PAH patients' follow-up. This additional information would allow better stratification of the patient, leading to optimized and personalized therapeutic management.

Tsantan Sumtang Restored Right Ventricular Function in Chronic Hypoxia-Induced Pulmonary Hypertension Rats

Background: Tsantan Sumtang originated from Four Tantras, which consisted of Choerospondias axillaris (Roxb.) B. L. Burtt and A. W. Hill, Santalum album L., and Myristica fragrans Houtt. The three herbs are in ratio 1:1:1. This medication is widely used for cardiovascular diseases.

Aims: The purpose of this study was to explore the effect of Tsantan Sumtang on right ventricular (RV) function in hypoxia-induced pulmonary hypertension (HPH) rats and investigate the underlying mechanism.

Methods: Sixty male Sprague-Dawley (SD) rats were divided into control, hypoxia, and hypoxia + Tsantan Sumtang (1.0, 1.25, and 1.5 g•kg⁻¹•d⁻¹) groups. Chronic hypoxia was induced by putting the rats inside a hypobaric chamber for four weeks and adjusting the inner pressure and oxygen content to match an altitude of 4500 m. Echocardiography was used to assess RV function and right ventricular-pulmonary arterial (RV-PA) coupling. The physiological parameters of the animals were also evaluated. Morphological characteristics of RV were assessed by hematoxylin and eosin (H&E) staining and TEM. Masson’s trichrome staining, immunohistochemical staining, western blotting, and TUNEL assay were used to assess fibrosis and apoptosis levels. The antioxidant and anti-apoptosis properties of Tsantan Sumtang were also evaluated. The effect of Tsantan Sumtang on ROCK signaling pathway was evaluated using real-time quantitative PCR and western blotting.

Results: We established an HPH rat model as indicated by the significant increases in the physiological parameters of the rats. Tsantan Sumtang showed a significant cardiac-protective function and an improved effect on RV-PA coupling. Moreover, Tsantan Sumtang treatment inhibited fibrosis and alleviated apoptosis and oxidative stress in RV. In terms of mechanism, Tsantan Sumtang reduced the expression of ROCK (ROCK1, ROCK2) in RV, inhibited cardiac remodeling-related transcription factors (NFATc3, P-STAT3), and regulated apoptosis-related proteins.

Conclusion: Tsantan Sumtang was able to restore RV function, improve RV-PA coupling, recover hemodynamic and hematological indexes, and protect RV against structural maladaptive remodeling in the HPH rats. These findings demonstrated that Tsantan Sumtang protects the function of RV in HPH rats. The antioxidant and anti-apoptosis properties of Tsantan Sumtang may be responsible for inhibiting the ROCK signaling pathway.

Echocardiographic Changes and Long-Term Clinical Outcomes in Pediatric Patients With Pulmonary Arterial Hypertension Treated With Bosentan for 72 Weeks: A Post-hoc Analysis From the FUTURE 3 Study

FormUlation of bosenTan in pUlmonary arterial hypeRtEnsion (FUTURE) 3 was a 24-week open-label, prospective, and randomized phase 3 study that assessed the pharmacokinetics of bosentan 2 mg/kg b.i.d. or t.i.d. in children with pulmonary arterial hypertension (PAH). We report findings from a post-hoc analysis that explored the prognostic value of echocardiographic changes during FUTURE 3 in relation to clinical outcomes observed during the 24-week core study and 48-week extension. Patients aged ≥3 months to <12 years (n = 64) received oral doses of bosentan 2 mg/kg b.i.d. or t.i.d. (1:1) for 24 weeks, after which they were eligible to enter the extension with continued bosentan administration. Echocardiographic evaluations were performed at baseline, Week 12, and 24 of the core study via central reading, and analyzed post-hoc for correlation with clinical outcomes (time to PAH worsening, time to death, and vital status). Sixty-four patients were randomized in the core study [median (IQR) age 3.8 (1.7-7.8) years]; and 58 patients (90.6%) entered the 48-week extension. Most of the patients (68.8%) were receiving ≥1 PAH medication at baseline. Echocardiographic changes during the core study were small but with high variability. There were statistically significant associations at Week 24 between worsening of the parameters, systolic left ventricular eccentricity index (LVEIS) and E/A ratio mitral valve flow, and the outcomes of time to death and time to PAH worsening. Additional studies that utilize simple and reproducible echocardiographic assessments are needed to confirm these findings and subsequently identify potential treatment goals in pediatric PAH.

Echocardiography for the Assessment of Pulmonary Hypertension and Congenital Heart Disease in the Young

While invasive assessment of hemodynamics and testing of acute vasoreactivity in the catheterization laboratory is the gold standard for diagnosing pulmonary hypertension (PH) and pulmonary vascular disease (PVD) in children, transthoracic echocardiography (TTE) serves as the initial diagnostic tool. International guidelines suggest several key echocardiographic variables and indices for the screening studies when PH is suspected. However, due to the complex anatomy and special physiological considerations, these may not apply to patients with congenital heart disease (CHD). Misinterpretation of TTE variables can lead to delayed diagnosis and therapy, with fatal consequences, or–on the other hand-unnecessary invasive diagnostic procedures that have relevant risks, especially in the pediatric age group. We herein provide an overview of the echocardiographic workup of children and adolescents with PH with a special focus on children with CHD, such as ventricular/atrial septal defects, tetralogy of Fallot or univentricular physiology. In addition, we address the use of echocardiography as a tool to assess eligibility for exercise and sports, a major determinant of quality of life and outcome in patients with PH associated with CHD.

Impact of right ventricular contractile reserve during low-load exercise on exercise intolerance in heart failure

AIMS

Traditional criteria for heart transplantation by cardiopulmonary exercise testing (CPX) include peak oxygen uptake (VO2 ) < 14 mL/kg/min. Reaching a sufficient exercise load is challenging for patients with refractory heart failure (HF) because of their exercise intolerance. Recently, a substantial impact of right ventricular (RV) dysfunction was highlighted on urgent heart transplantation and mortality. This study aims to investigate the impact of RV contractile reserve, assessed by low-load exercise stress echocardiography (ESE), on exercise intolerance defined as peak VO2  < 14 mL/kg/min, in patients with HF.

METHODS AND RESULTS

We prospectively examined 67 consecutive patients hospitalized for HF who underwent ESE and CPX under a stabilized HF condition. Although low-load ESE was defined as 25 W load exercise, an increment in RV systolic (s') velocity was regarded as the preservation of RV contractile reserve. All patients completed low-load ESE. During low-load ESE, the variation in RV s' velocity significantly correlated with peak VO2 (r = 0.787, P < 0.001). The change in RV s' velocity during low-load ESE accurately identified patients with peak VO2  < 14 mL/kg/min (area under the curve, 0.95; sensitivity, 92%; specificity, 85%). The intraclass correlation coefficient for intra-observer and inter-observer agreement for the change in RV s' velocity was 0.96 (95% confidence interval, 0.88-0.99, P < 0.001) and 0.86 (95% confidence interval, 0.64-0.95, P < 0.001), respectively. The RV-to-pulmonary circulation (PC) coupling, which was assessed by the slope of the relationship between RV s' velocity and pulmonary artery systolic pressure at rest and low-load exercise, was worse in the low-peak VO2 group (<14 mL/kg/min) than the preserved-peak VO2 group (≥14 mL/kg/min).

CONCLUSIONS

The change in RV s' velocity during low-load ESE could estimate the exercise capacity in HF patients. The assessments of RV contractile reserve and RV-to-PC coupling could be clinically beneficial to distinguish high-risk HF patients.

Right ventricular-arterial uncoupling independently predicts survival in COVID-19 ARDS

AIM

To investigate the prevalence and prognostic impact of right heart failure and right ventricular-arterial uncoupling in Corona Virus Infectious Disease 2019 (COVID-19) complicated by an Acute Respiratory Distress Syndrome (ARDS).

METHODS

Ninety-four consecutive patients (mean age 64 years) admitted for acute respiratory failure on COVID-19 were enrolled. Coupling of right ventricular function to the pulmonary circulation was evaluated by a comprehensive trans-thoracic echocardiography with focus on the tricuspid annular plane systolic excursion (TAPSE) to systolic pulmonary artery pressure (PASP) ratio RESULTS: The majority of patients needed ventilatory support, which was noninvasive in 22 and invasive in 37. There were 25 deaths, all in the invasively ventilated patients. Survivors were younger (62 ± 13 vs. 68 ± 12 years, p = 0.033), less often overweight or usual smokers, had lower NT-proBNP and interleukin-6, and higher arterial partial pressure of oxygen (PaO2)/fraction of inspired O2 (FIO2) ratio (270 ± 104 vs. 117 ± 57 mmHg, p < 0.001). In the non-survivors, PASP was increased (42 ± 12 vs. 30 ± 7 mmHg, p < 0.001), while TAPSE was decreased (19 ± 4 vs. 25 ± 4 mm, p < 0.001). Accordingly, the TAPSE/PASP ratio was lower than in the survivors (0.51 ± 0.22 vs. 0.89 ± 0.29 mm/mmHg, p < 0.001). At univariate/multivariable analysis, the TAPSE/PASP (HR: 0.026; 95%CI 0.01-0.579; p: 0.019) and PaO2/FIO2 (HR: 0.988; 95%CI 0.988-0.998; p: 0.018) ratios were the only independent predictors of mortality, with ROC-determined cutoff values of 159 mmHg and 0.635 mm/mmHg, respectively.

CONCLUSIONS

COVID-19 ARDS is associated with clinically relevant uncoupling of right ventricular function from the pulmonary circulation; bedside echocardiography of TAPSE/PASP adds to the prognostic relevance of PaO2/FIO2 in ARDS on COVID-19.

Echocardiographic evaluation of right ventricular-arterial coupling in pulmonary hypertension

Pulmonary hypertension (PH) is a hemodynamic condition characterized by chronically elevated mean pulmonary artery pressure (m-PAP ≥ 25 mmHg) measured at rest by right heart catheterization (RHC). It includes a pre-capillary and a post-capillary form. Pulmonary artery hypertension (PAH) is a pre-capillary form of PH potentially generated by several heterogeneous systemic disorders, whose main hemodynamic change is represented by severely increased pulmonary vascular resistance (PVR). In order to preserve an efficient right ventricular-arterial (RV-PA) coupling, the right ventricle (RV) adapts to this chronic increase of its afterload, with a compensatory hypertrophy, until RV dilatation and dysfunction occur. Right ventricular (RV) function and especially RV-PA coupling assessment showed to be very important prognostic markers in this subset of patients, especially for those with pre-capillary PH. The aim of this review is to provide a pathophysiological insight into the spectrum of RV adaptive changes occurring in response to chronic increase of RV afterload and to present the role of echocardiographic parameters as possible tools for early non-invasive evaluation of RV-PA coupling, before overt heart failure ensues.

Advanced risk stratification of intermediate risk group in pulmonary arterial hypertension

In 301 treatment-naïve patients with pulmonary arterial hypertension stratified by the European Society of Cardiology/European Respiratory Society risk score, further stratification of intermediate-risk patients based on six-minute walk distance and the tricuspid annular plane systolic excursion/systolic pulmonary artery pressure ratio identified a subset with mortality rates comparable to low-risk patients.

Mechanics of right ventricular dysfunction in pulmonary arterial hypertension and heart failure with preserved ejection fraction

Right ventricular (RV) dysfunction is the most important determinant of survival in patients with pulmonary hypertension (PH). The manifestations of RV dysfunction not only include changes in global RV systolic function but also abnormalities in the pattern of contraction and synchrony. The effects of PH on the right ventricle have been mainly studied in patients with pulmonary arterial hypertension (PAH). However, with the demographic shift towards an aging population, heart failure with preserved ejection fraction (HFpEF) has become an important etiology of PH in recent years. There are significant differences in RV mechanics, function and adaptation between patients with PAH and HFpEF (with or without PH), which are related to different patterns of remodeling and dysfunction. Due to the unique features of the RV chamber, its connection with the main pulmonary artery and the pulmonary circulation, an understanding of the mechanics of RV function and its clinical significance is mandatory for both entities. In this review, we describe the mechanics of the pressure overloaded right ventricle. We review the different mechanical components of RV dysfunction and ventricular dyssynchrony, followed by insights via analysis of pressure-volume loop, energetics and novel blood flow patterns, such as vortex imaging. We conduct an in-depth comparison of prevalence and characteristics of RV dysfunction in HFpEF and PAH, and summarize key outcome studies. Finally, we provide a perspective on needed and expected future work in the field of RV mechanics.

Effects of Sacubitril/Valsartan on the Right Ventricular Arterial Coupling in Patients with Heart Failure with Reduced Ejection Fraction

BACKGROUND

right ventricle-pulmonary artery (RV-PA) coupling assessed by measuring the tricuspid anular plane systolic excursion (TAPSE)/pulmonary artery systolic pressure (PASP) ratio has been recently proposed as an early marker of right ventricular dysfunction in patients with heart failure with a reduced ejection fraction (HFrEF).

METHODS

As the effects of sacubitril/valsartan therapy on RV-PA coupling remain unknown, this study aimed to analyse the effect of this drug on TAPSE/PASP in patients with HFrEF. We retrospectively analysed all outpatients with HFrEF referred to our unit between October 2016 and July 2018.

RESULTS

At the 1-year follow-up, sacubitril/valsartan therapy was associated with a significant improvement in TAPSE (18.26 ± 3.7 vs. 19.6 ± 4.2 mm, p < 0.01), PASP (38.3 ± 15.7 vs. 33.7 ± 13.6, p < 0.05), and RV-PA coupling (0.57 ± 0.25 vs. 0.68 ± 0.30 p < 0.01). These improvements persisted at the 2-year follow-up. In the multivariable analysis, the improvement in the RV-PA coupling was independent of the left ventricular remodelling.

CONCLUSIONS

in patients with HFrEF, sacubitril/valsartan improved the RV-PA coupling; however, further trials are necessary to evaluate the role of sacubitril/valsartan in the treatment of right ventricle (RV) dysfunction either associated or not associated with left ventricular dysfunction.

Pulmonary artery banding is a relevant model to study the right ventricular remodeling and dysfunction that occurs in pulmonary arterial hypertension

Right ventricular (RV) dysfunction determines mortality in patients with pulmonary arterial hypertension (PAH) and RV pressure loading. Experimental models commonly use Sugen hypoxia (SuHx)-induced PAH, monocrotaline (MCT)-induced PAH, or pulmonary artery banding (PAB). Because PAH models cannot interrogate RV effects or therapies independent of pulmonary vascular effects, we aimed to compare RV function and fibrosis in experimental PAB vs. PAH. Thirty rats were randomized to either sham controls, PAB, SuHx-, or MCT-induced PAH. RV pressures and function were assessed by high-fidelity pressure-tipped catheters and by echocardiography. RV myocyte hypertrophy, fibrosis, and capillary density were quantified from hematoxylin-eosin, picrosirius red-stained, and CD31-immunostained RV sections, respectively. RV pressures and the RV-to-left ventricular pressure ratio were significantly increased in all three groups to a similar degree (PAB 65 ± 17 mmHg, SuHx 72 ± 16 mmHg, and MCT 70 ± 12 mmHg) vs. controls (23 ± 2 mmHg, all P < 0.01). RV dilatation, hypertrophy, and fibrosis were similarly increased, and capillary density decreased, in the three models (RV fibrosis; PAB 13.3 ± 3.6%, SuHx 9.8 ± 3.0% and MCT 10.9 ± 2.4% vs control 5.5 ± 1.1%, all P < 0.05). RV function was similarly decreased in all models vs. controls. We observed comparable RV dilatation, hypertrophy, systolic and diastolic dysfunction, fibrosis, and capillary rarefaction in rat models of PAB, SuHx-, and MCT-induced PAH. These results suggest that PAB, when sufficiently severe, induces features of maladaptive RV remodeling and can be used to investigate RV pathophysiology and therapy effects independent of pulmonary vascular resistance.NEW & NOTEWORTHY Although animal models of pulmonary arterial hypertension and pressure loading are important to study right ventricular (RV) pathophysiology, pulmonary arterial hypertension models cannot interrogate RV responses independent of pulmonary vascular effects. Comparing three commonly used rat models under similar elevated RV pressure, we found that all models resulted in comparable maladaptive RV remodeling and dysfunction. Thus, these findings suggest that the pulmonary artery banding model can be used to investigate mechanisms of RV dysfunction in RV pressure overload and the effect of potential therapies.

Right ventricular dyssynchrony: from load-independent right ventricular function to wall stress in severe pulmonary arterial hypertension

Right ventricular (RV) dyssynchrony has been related to outcome in pulmonary arterial hypertension. Prospectively, we performed echocardiography with measurement of right ventricular dyssynchrony and pressure-volume loop catheterization in 27 pulmonary arterial hypertension patients. Afterload and diastolic function emerged as determinates of wall stress, which results in dyssynchrony.

Pulmonary Hypertension in Heart Failure Patients

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

Right Ventricular Dysfunction Staging System for Mortality Risk Stratification in Heart Failure With Preserved Ejection Fraction

Right ventricular dysfunction (RVD) parameters are increasingly important features in heart failure with preserved ejection fraction (HFpEF). We sought to evaluate the prognostic impact of a progressive RVD staging system by combining the tricuspid annular plane systolic excursion (TAPSE) to pulmonary artery systolic pressure (TAPSE/PASP) ratio with functional tricuspid regurgitation (TR) severity. We prospectively included 1355 consecutive HFpEF patients discharged for acute heart failure (HF). Of them, in 471 (34.7%) patients, PASP could not be accurately measured, leaving the final sample size to be 884 patients. Patients were categorized as Stage 1: TAPSE/PASP ≥ 0.36 without significant TR; stage 2: TAPSE/PASP ≥ 0.36 with significant TR; stage 3: TAPSE/PASP < 0.36 without significant TR; and stage 4: TAPSE/PASP < 0.36 with significant TR. By the 1 year follow-up, 207 (23.4%) patients had died. We found a significant and graded association between RVD stages and mortality rates (15.8%, 25%, 31.2%, and 45.4% from stage 1 to stage 4, respectively; log-rank test, p < 0.001). After multivariable adjustment, and compared to stage 1, stages 3 and 4 were independently associated with mortality risk (HR: 1.8219; 95% CI 1.308–2.538; p < 0.001 and HR = 2.2632; 95% CI 1.540–3.325; p < 0.001, respectively). A RVD staging system, integrating TAPSE/PASP and TR, provides a comprehensive and widely available tool for risk stratification in HFpEF.

Echocardiographic Assessment of Right Ventriculo-arterial Coupling: Clinical Correlates and Prognostic Impact in Heart Failure Patients Undergoing Cardiac Resynchronization Therapy

BACKGROUND

Right ventriculo-arterial coupling (RV-PA) can be estimated by echocardiography using the ratio between tricuspid annular plane systolic excursion (TAPSE) and pulmonary artery systolic pressure (PASP) and it has prognostic value in the general heart failure (HF) population. We aimed to study the clinical correlates and prognostic value of RV-PA in HF patients undergoing cardiac resynchronization therapy (CRT).

METHODS

We retrospectively studied 70 HF patients undergoing CRT implantation.

RESULTS

RV-PA coupling was estimated by TAPSE/PASP ratio using baseline echocardiography. Non-response to CRT was defined as improvement of left ventricular ejection fraction < 5% in a follow-up echo 6-12 months after CRT. Those with lower TAPSE/PASP ratios (worse RV-PA coupling) had higher NT-proBNP concentrations and increased E/e' ratio. TAPSE/PASP ratio and PASP, but not TAPSE, predicted nonresponse to CRT with TAPSE/PASP ratio showing the best discriminative ability with a sensitivity of 76% and specificity of 71%. Among these parameters, PASP independently predicted all-cause mortality.

CONCLUSIONS

RV-PA coupling estimated by TAPSE/PASP ratio was associated with established prognostic markers in HF. It numerically outperformed PASP and TAPSE in predicting the response to CRT. Our data suggest that this simple and widely available echocardiographic parameter conveys significant pathophysiological and prognostic meaning in HF patients undergoing CRT.