Right heart imaging in patients with heart failure: a tale of two ventricles

Biventricular function after Ebstein anomaly repair from a single-center echocardiography study

OBJECTIVE

We aimed to examine biventricular remodeling and function after Ebstein anomaly (EbA) surgical correction using echocardiographic techniques, particularly, the relations between the biventricular changes and the EbA types.

METHODS

From April 2015 to August 2022, 110 patients with EbA were included in this retrospective study based on the Carpentier classification. Echocardiography assessments during the preoperative, early, and mid-term postoperative periods were performed.

RESULTS

The 54 patients with types A and B EbA were included in group 1, whereas the 56 patients with types C and D were in group 2. Seventy-eight patients underwent surgical correction of EbA. The median age at operation was 8.8 years. During the mid-term follow-up, only 9.1% of the patients had moderate or severe tricuspid regurgitation. Right ventricular (RV) systolic function worsened in group 2 at discharge (fractional area change: 27.6 ± 11.2 vs. 35.4 ± 11.5 [baseline], P < 0.05; global longitudinal strain: -10.8 ± 4.4 vs. -17.9 ± 4.7 [baseline], P = 0.0001). RV function slowly recovered at a mean of 12 months of follow-up. Regarding left ventricular (LV) and RV systolic function, no statistical difference was found between before and after surgery in group 1.

CONCLUSION

A high success rate of surgical correction of EbA, with an encouraging durability of the valve, was noted. Biventricular systolic function was maintained fairly in most patients with types A and B postoperatively. A late increase in RV systolic function after an initial reduction and unchanged LV systolic function were observed in the patients with types C and D postoperatively.

The Echocardiographic Evaluation of the Right Heart: Current and Future Advances

PURPOSE OF REVIEW

To discuss physiologic and methodologic advances in the echocardiographic assessment of right heart (RH) function, including the emergence of artificial intelligence (AI) and point-of-care ultrasound.

RECENT FINDINGS

Recent studies have highlighted the prognostic value of right ventricular (RV) longitudinal strain, RV end-systolic dimensions, and right atrial (RA) size and function in pulmonary hypertension and heart failure. While RA pressure is a central marker of right heart diastolic function, the recent emphasis on venous excess imaging (VExUS) has provided granularity to the systemic consequences of RH failure. Several methodological advances are also changing the landscape of RH imaging including post-processing 3D software to delineate the non-longitudinal (radial, anteroposterior, and circumferential) components of RV function, as well as AI segmentation- and non-segmentation-based quantification. Together with recent guidelines and advances in AI technology, the field is shifting from specific RV functional metrics to integrated RH disease-specific phenotypes. A modern echocardiographic evaluation of RH function should focus on the entire cardiopulmonary venous unit-from the venous to the pulmonary arterial system. Together, a multi-parametric approach, guided by physiology and AI algorithms, will help define novel integrated RH profiles for improved disease detection and monitoring.

Isolated Tricuspid Regurgitation Alternans in Acute Myocardial Infarction: A Rare Entity

Pulsus alternans is characterized by alternating strong and weak beats, and occurs with failing hearts. Left ventricular pulsus alternans is known to occur with ischemic heart disease, valvular heart disease, and outflow tract obstructions. Isolated right ventricular (RV) pulsus alternans is a rare entity. We report the case of a 51-year-old male patient who presented with inferior wall myocardial infarction and cardiogenic shock. He was diagnosed to have an isolated tricuspid regurgitation alternans signifying severe RV dysfunction. The patient was resuscitated and treated with primary percutaneous intervention to the right coronary artery. We also review the literature associated with RV pulsus alternans and its mechanisms.

Right Ventricular Diastolic Performance in Patients With Chronic Thromboembolic Pulmonary Hypertension Assessed by Echocardiography

Background: There have been no systemic studies about right heart filling pressure and right ventricular (RV) distensibility in patients with chronic thromboembolic pulmonary hypertension (CTEPH). Therefore, we aimed to explore combinations of echocardiographic indices to assess the stages of RV diastolic dysfunction.

Methods and Results: We recruited 32 healthy volunteers and 71 patients with CTEPH. All participants underwent echocardiography, cardiac catheterization (in patients with CTEPH), and a 6-min walk test (6MWT). The right atrial (RA) end-systolic area was adjusted for body surface area (BSA) (indexed RA area). RV global longitudinal diastolic strain rates (SRs) and RV ejection fraction (EF) were measured by speckle tracking and three-dimensional echocardiography (3D echo), respectively. All 71 patients with CTEPH underwent pulmonary endarterectomy. Of the 71 patients, 52 (73%) had decreased RV systolic function; 12 (16.9%), 26 (36.6%), and 33 (46.5%) patients had normal RV diastolic pattern, abnormal relaxation (stage 1), and pseudo-normal patterns (stage 2), respectively. The receiver operating characteristic curve analysis showed that the optimal cut-off values of early diastolic SR <0.8 s⁻¹ and indexed RA area > 8.8 cm²/BSA had the best accuracy in identifying patients with RV diastolic dysfunction, with 87% sensitivity and 82% specificity. During a mean follow-up of 25.2 months after pulmonary endarterectomy, the preoperative indexed RA area was shown as an independent risk factor of the decreased 6MWT distance.

Conclusions: Measuring early diastolic SR and indexed RA area would be useful in stratifying RV diastolic function.

Isolated Tricuspid Valve Surgery: the Auckland Experience 2011-2019

INTRODUCTION

Isolated tricuspid valve surgery is an uncommon operation. Historical reports, including a previous review from our unit, demonstrated high morbidity and mortality associated with this operation. Many of these patients had severely impaired right ventricular function at the time of the surgery. Since our previous review, we have actively encouraged our local cardiologists to refer patients with severe isolated tricuspid disease for surgery before right ventricular remodelling occurs. This present study was performed to assess our current results.

MATERIAL AND METHODS

A prospectively-maintained hospital database was used to identify all adult non-congenital patients receiving standalone tricuspid valve repair or replacement at New Zealand's largest cardiothoracic surgical unit from July 2011 to July 2019. Additional demographic and clinical data were collected by review of patient electronic records.

RESULTS

During the 8-year study period, a total of 50 patients underwent isolated tricuspid valve surgery. Most patients were operated on for functional (40%) or rheumatic (30%) tricuspid disease. The majority of patients underwent surgery when the right ventricular function preoperatively was normal (30%) or mildly/moderately impaired (60%). Over half the patient sample (56%) underwent valve replacement. The 30-day mortality rate and stroke rate were 6% and 2% respectively. The medium-term survival was 80% at 4 years mean follow-up.

CONCLUSION

Isolated tricuspid surgery is no longer a high mortality operation when it is performed on patients who have preserved right ventricular function.

Traditional and Novel Imaging of Right Ventricular Function in Patients with Heart Failure and Reduced Ejection Fraction

PURPOSE OF REVIEW

This review attempts to summarize the role of standard and advanced echocardiographic techniques together with CMR in the evaluation of the RV in HF, providing an outlook on the recent evidence.

RECENT FINDINGS

In the last decade, there has been growing interest in the study of the RV, and it is now widely established that RV function is a strong predictor of mortality, in several cardiovascular diseases, in particular in the setting of heart failure (HF). The evaluation of RV function might be particularly challenging, which justifies the necessity of multi-modality imaging. The echocardiographic assessment remains the mainstay technique even though it might be complex, due to RV crescent shape and its position in the chest, requiring both qualitative and quantitative parameters. Cardiac magnetic resonance (CMR) represents a complementary exam which is particularly useful when precise structural and functional assessment are needed, considering the most recently developed sequences. Despite the technological improvement attested over the last years, there is still no universally accepted parameter that univocally defines RV function, hence the necessity to evaluate several parameters, combining different imaging techniques.

Diagnosis and treatment of right ventricular dysfunction in congenital heart disease

Right ventricular (RV) function is important for clinical status and outcomes in children and adults with congenital heart disease (CHD). In the normal RV, longitudinal systolic function is the major contributor to global RV systolic function. A variety of factors contribute to RV failure including increased pressure- or volume-loading, electromechanical dyssynchrony, increased myocardial fibrosis, abnormal coronary perfusion, restricted filling capacity and adverse interactions between left ventricle (LV) and RV. We discuss the different imaging techniques both at rest and during exercise to define and detect RV failure. We identify the most important biomarkers for risk stratification in RV dysfunction, including abnormal NYHA class, decreased exercise capacity, low blood pressure, and increased levels of NTproBNP, troponin T, galectin-3 and growth differentiation factor 15. In adults with CHD (ACHD), fragmented QRS is independently associated with heart failure (HF) symptoms and impaired ventricular function. Furthermore, we discuss the different HF therapies in CHD but given the broad clinical spectrum of CHD, it is important to treat RV failure in a disease-specific manner and based on the specific alterations in hemodynamics. Here, we discuss how to detect and treat RV dysfunction in CHD in order to prevent or postpone RV failure.

Right ventricle in heart failure with preserved ejection fraction

Heart failure with preserved ejection fraction (HFpEF) affects half of all patients with heart failure. While previously neglected, the right ventricle (RV) has sparked interest in recent years as a means for better understanding this condition and as a potential therapeutic target.

Right ventricular dysfunction (RVD) is present in 4%–50% of patients with HFpEF. The RV is intimately connected to the pulmonary circulation, and pulmonary hypertension is commonly implicated in the pathophysiology of RVD. The development of RVD in HFpEF may also be driven by comorbidities, such as chronic obstructive pulmonary disease, obesity, obstructive sleep apnoea and atrial fibrillation. The evaluation of RVD is particularly challenging due to anatomical and structural factors, as well as unique physiological characteristics of this chamber like load and interventricular dependency. Fractional area change, tricuspid annular plane systolic excursion and tricuspid annular systolic velocity are commonly used measurements of RV function. Speckle tracking echocardiography and cardiac magnetic resonance (CMR) are also gaining attention as important tools for the assessment of RV structure, fibre deformation and systolic performance. Further research is needed to confirm the utility and prognostic significance of RV [18F]fluorodeoxyglucose (FDG) positron emission tomography imaging as FDG accumulation is suggested to increase with progressive RVD. Targeted pharmacotherapy with phosphodiesterase inhibitors, guanylate–cyclase stimulators, nitrates and inhaled inorganic nitrites have yet to demonstrate improvement in RVD, compelling the need for evaluation and discovery of novel pharmacological interventions for this entity.

Echocardiographic and Clinical Correlates of Ejection Fraction Among 2000 Patients with Heart Failure in Western Saudi Arabia

Introduction

Heart failure (HF) affects about 320,000 Saudi individuals and is associated with a considerable negative impact on the patients’ quality of life. In literature, there is a lack of data about the echocardiographic abnormalities of HF patients in Saudi Arabia.

Aim of Work

To describe the echocardiographic findings of HF patients in Western Saudi Arabia.

Methodology

This was a retrospective record review study conducted on 2000 patients with chronic HF in Saudi Arabia. Demographic, clinical and echocardiographic data were collected and compared among patients with HF with reduced ejection fraction (HFrEF), ie, EF≤40%; HF with mid-range EF (HFmrEF), ie, EF=41–49%; and HF with preserved EF (HFpEF), ie, EF≥50%.

Results

Among the 2000 patients studied, females constituted 46.3% of the sample. About 52% of females had HFpEF, whilst 70% of males had HFrEF (p<0.0001). Diastolic dysfunction occurred in 98% of HFpEF versus 78% of HFrEF (p<0.0001). Patients with HFrEF had higher left-ventricular diastolic (LVd) volume (1536 versus 826), higher left-ventricular systolic (LVs) volume (1660 vs 772), higher left atrial volume (1344 vs 875), higher aortic root dimension (1144 vs 929) and lower fractional shortening (FS) (267 vs 1213) than patients with HFpEF (p<0.0001).

Conclusion

HFpEF was more common among females and was associated with higher rates of diastolic dysfunction and higher FS. HFrEF was prevalent among males and associated with higher LVd, LVs, left atrium volume and aortic root dimensions.

Preliminary Experience Using Diastolic Right Ventricular Pressure Gradient Monitoring in Cardiac Surgery

OBJECTIVES

Right ventricular (RV) dysfunction in cardiac surgery is associated with increased mortality and morbidity and difficult separation from cardiopulmonary bypass (DSB). The primary objective of the present study was to describe the prevalence and characteristics of patients with abnormal RV diastolic pressure gradient (PG). The secondary objective was to explore the association among abnormal diastolic PG and DSB, postoperative complications, high central venous pressure (CVP), and high RV end-diastolic pressure (RVEDP).

DESIGN

Retrospective and prospective validation study.

SETTING

Tertiary care cardiac institute.

PARTICIPANTS

Cardiac surgical patients (n=374) from a retrospective analysis (n=259) and a prospective validation group (n=115).

INTERVENTION

RV pressure waveforms were obtained using a pulmonary artery catheter with a pacing port opened at 19 cm distal to the tip of the catheter. Abnormal RV diastolic PG was defined as >4 mmHg. Both elevated RVEDP and high CVP were defined as >16 mmHg.

MEASUREMENTS AND MAIN RESULTS

From the retrospective and validation cohorts, 42.5% and 48% of the patients had abnormal RV diastolic PG before cardiac surgery, respectively. Abnormal RV diastolic PG before cardiac surgery was associated with higher EuroSCORE II (odds ratio 2.29 [1.10-4.80] v 1.62 [1.10-3.04]; p = 0.041), abnormal hepatic venous flow (45% v 29%; p = 0.038), higher body mass index (28.9 [25.5-32.5] v 27.0 [24.9-30.5]; p = 0.022), pulmonary hypertension (48% v 37%; p = 0.005), and more frequent DSB (32% v 19%; p = 0.023). However, RV diastolic PG was not an independent predictor of DSB, whereas RVEDP (odds ratio 1.67 [1.09-2.55]; p = 0.018) was independently associated with DSB. In addition, RV pressure monitoring indices were superior to CVP in predicting DSB.

CONCLUSION

Abnormal RV diastolic PG is common before cardiac surgery and is associated with a higher proportion of known preoperative risk factors. However, an abnormal RV diastolic PG gradient is not an independent predictor of DSB in contrast to RVEDP.

Cardiac magnetic resonance imaging as a prognostic biomarker in treatment-naïve pulmonary hypertension

PURPOSE

Targeted treatment for pulmonary arterial hypertension (PAH), diagnosed via right heart catheterization (RHC), has been shown to improve morbidity and mortality. Identifying characteristics that predict clinical worsening has been challenging. We sought to evaluate the role of cardiac Magnetic Resonance Imaging (CMR) as a predictor of clinical worsening in a cohort of treatment-naïve pulmonary hypertension (PH) patients.

METHODS

We performed a retrospective single center analysis of all adults with newly diagnosed treatment-naïve PH between January 1st 2013 and January 1st 2019. Patients with World Health Organization (WHO)-Group I PAH or WHO-Group II/III PH disease, who underwent both CMR (Signa Horizon 1.5 T, General Electric, Milwaukee, WI and Siemens Espree 1.5 T, Munich, Germany) and RHC testing prior to targeted PAH treatment, were included for analysis. Cox proportional hazards models were constructed.

RESULTS

A total of 38 patients, of which 12 (32 %) experienced the primary outcome of clinical worsening. were included in the final analysis, Patients with clinical worsening were significantly more likely to have RV dysfunction by CMR (including lower RV ejection fraction (HR 0.93, p = 0.007) and more RV dilation (HR 1.02, p = 0.005-0.021)) and RHC (including worse pulmonary vascular resistance (HR 1.32, p < 0.001)), even after adjustment for disease severity. Both CMR and RHC measures of RV dysfunction were found to be equally effective in predicting clinical worsening, regardless of PH etiology.

CONCLUSIONS

In treatment-naïve PH patients, including those with WHO-Group II/III disease, both CMR and RHC measures independently and significantly predicted clinical worsening, even after adjustment for disease severity.

Echocardiographic evaluations of right ventriculo-arterial coupling in experimental and clinical pulmonary hypertension

BACKGROUND

Tricuspid annular systolic excursion (TAPSE) or velocities (s') and right ventricular (RV) end-systolic dimensions are predictors of outcome in patients with pulmonary hypertension (PH). We explored the value of combining peak s' and RV end-systolic area index (RVESAi) as a surrogate of RV-pulmonary artery (RV-PA) coupling in a large animal of precapillary PH as well as clinically.

METHOD

The first experimental group included four control and four piglets with thromboembolic disease. RV-PA coupling was assessed by ventricular to arterial elastance ratio (Ees/Ea) at baseline, after esmolol and dobutamine administration. Echocardiographic metrics included s', TAPSE, fractional area change (RVFAC), and RVESAi. The findings were validated in six piglets with severe PH. Clinical cohorts were stable outpatients (n = 141) and acutely decompensated pulmonary arterial hypertension (n = 48).

RESULTS

In the first experimental group, the best linear correlates of Ees/Ea were s' (R2  = .51, p < .001) and RVESAi (R2  = .50, p < .001), while RVFAC (R2  = .17, p = .01) and TAPSE showed weaker association (R2  = .21, p = .39). The ratio s'/RVESAi showed nominally but not significantly (higher) association with Ees/Ea (R2  = .58, p < .01). The association between changes in s'/RVESAi and Ees/Ea was strong (R2  = .56, p < .001). In more severe PH, Ees/Ea and changes in Ees/Ea correlated significantly with s'/RVESAi and changes in s'/RVESAi (R2  = .69; p < .001 and R2  = .64, p < .001, respectively). In the two clinical cohorts, the s'/RVESAi did not emerge as a stronger predictor of outcome than RVESAi.

CONCLUSION

RV s'/RVESAi index represents a reasonable bedside-usable surrogate of RV-PA coupling and of its acute variations in PH. Its incremental prognostic value over end-systolic dimension alone remains to be proven.

Myocardial velocity, intra-, and interventricular dyssynchrony evaluated by tissue phase mapping in pediatric heart transplant recipients

BACKGROUND

Endomyocardial biopsy (EMB) is the standard method for detecting allograft rejection in pediatric heart transplants (Htx). As EMB is invasive and carries a risk of complications, there is a need for a noninvasive alternative for allograft monitoring.

PURPOSE

To quantify left and right ventricular (LV & RV) peak velocities, velocity twist, and intra-/interventricular dyssynchrony using tissue phase mapping (TPM) in pediatric Htx compared with controls, and to explore the relationship between global cardiac function parameters and the number of rejection episodes to these velocities and intra-/interventricular dyssynchrony.

STUDY TYPE

Prospective.

SUBJECTS

Twenty Htx patients (age: 16.0 ± 3.1 years, 11 males) and 18 age- and sex-matched controls (age: 15.5 ± 4.3 years, nine males).

FIELD STRENGTH/SEQUENCE

5T; 2D balanced cine steady-state free-precession (bSSFP), TPM (2D cine phase contrast with three-directional velocity encoding).

ASSESSMENT

LV and RV circumferential, radial, and long-axis velocity-time curves, global and segmental peak velocities were measured using TPM. Short-axis bSSFP images were used to measure global LV and RV function parameters.

STATISTICAL TESTS

A normality test (Lilliefors test) was performed on all data. For comparisons, a t-test was used for normally distributed data or a Wilcoxon rank-sum test otherwise. Correlations were determined by a Pearson correlation.

RESULTS

Htx patients had significantly reduced LV (P < 0.05-0.001) and RV (P < 0.05-0.001) systolic and diastolic global and segmental long-axis velocities, reduced RV diastolic peak twist (P < 0.01), and presented with higher interventricular dyssynchrony for long-axis and circumferential motions (P < 0.05-0.001). LV diastolic long-axis dyssynchrony (r = 0.48, P = 0.03) and RV diastolic peak twist (r = -0.64, P = 0.004) significantly correlated with the total number of rejection episodes.

DATA CONCLUSION

TPM detected differences in biventricular myocardial velocities in pediatric Htx patients compared with controls and indicated a relationship between Htx myocardial velocities and rejection history.

LEVEL OF EVIDENCE

2 Technical Efficacy Stage: 3 J. Magn. Reson. Imaging 2020;51:1212-1222.

Forgotten No More: A Focused Update on the Right Ventricle in Cardiovascular Disease

In the last decade, there has been renewed interest in the study of the right ventricle. It is now well established that right ventricular function is a strong predictor of mortality, not only in heart failure but also in pulmonary hypertension, congenital heart disease, and cardiothoracic surgery. The right ventricle is part of a cardiopulmonary unit with connections to the pulmonary circulation, venous return, atria, and left ventricle. In this context, ventriculoarterial coupling, interventricular interactions, and pericardial constraint become important to understand right ventricular adaptation to injury or abnormal loading conditions. This state-of-the-art review summarizes major advances that occurred in the field of right ventricular research over the last decade. The first section focuses on right ventricular physiology and pulmonary circulation. The second section discusses the emerging data on right ventricular phenotyping, highlighting the importance of myocardial deformation (strain) imaging and assessment of end-systolic dimensions. The third section reviews recent clinical trials involving patients at risk for or with established right ventricular failure, focusing on beta blockade, phosphodiesterase inhibition, and mechanical support of the failing right heart. The final section presents a perspective on active areas of research that are most likely to translate in clinical practice in the next decade.

[Pathophysiology of right ventricular hemodynamics]

The right ventricle (RV) plays a key role in the maintenance of an adequate cardiac output whatever the demand, and thus contributes to the optimization of the ventilation/perfusion ratio. The RV has a thin wall and it buffers the physiological increases in systemic venous return without causing a deleterious rise in right atrial pressure (RAP). The RV is coupled to the pulmonary circulation which is a low pressure, low resistance, high compliance system. In the healthy subject at rest, the contribution of the RV to right heart systolic function is surpassed by the contribution of both left ventricular contraction and the respiratory pump. RV systolic function plays a contributory role during exercise and in patients with pulmonary hypertension. The RV compensates better for volume overload than for pressure overload and is more capable of sustaining chronic increases in load than acute ones. An impaired RV-pulmonary artery coupling leads to a major mismatch between RV function and arterial load ("afterload mismatch") and is associated progressively with a low cardiac output and a high RAP. Right ventricular dysfunction is involved in the pathophysiology of both cardiovascular and pulmonary diseases, and may partly explain the deleterious haemodynamic consequences of mechanical ventilation.

Non-invasive right ventricular load adaptability indices in patients with scleroderma-associated pulmonary arterial hypertension

Scleroderma-associated pulmonary arterial hypertension (SSc-PAH) is associated with worse outcome than idiopathic pulmonary arterial hypertension (IPAH), potentially due to worse right ventricular adaptation to load as suggested by pressure–volume loop analysis. The value of non-invasive load-adaptability metrics has not been fully explored in SSc-PAH. This study sought to assess whether patients with incident SSc-PAH have worse echocardiographic load-adaptability metrics than patients with IPAH. Twenty-two patients with incident SSc-PAH were matched 1:1 with IPAH based on pulmonary vascular resistance. Echocardiographic load-adaptability indices were divided into: surrogates of ventriculo-arterial coupling (e.g. right ventricular area change/end-systolic area), indices reflecting the proportionality of load adaptation (e.g. tricuspid regurgitation velocity-time integral normalized for average right ventricular radius), and simple ratios (e.g. tricuspid annular plane systolic excursion/right ventricular systolic pressure). The prognostic value of these indices for clinical worsening (i.e. death, transplant, or hospitalization for heart failure) at one year was explored. The two groups were comprised of patients of similar age, with similar cardiac index, pulmonary resistance, capacitance and NT-proBNP levels (p > 0.10). There was no difference in baseline right ventricular dimension, function or load-adaptability indices. At one year, eight (36.4%) SSc-PAH patients had experienced clinical worsening (eight hospitalizations and two deaths) versus one hospitalization in the IPAH group. Load adaptation at one year in survivors was not worse in SSc-PAH (p > 0.33). Patients with IPAH responded better to therapy than SSc-PAH in terms of reduction of right ventricular areas at one year (p < 0.05). Right ventricular load-adaptability echocardiographic indices do not appear to capture the increased risk of negative outcomes at one year associated with SSc-PAH.

Optimizing right ventricular focused four-chamber views using three-dimensional imaging, a comparative magnetic resonance based study

Obtaining focused right ventricular (RV) apical view remains challenging using conventional two-dimensional (2D) echocardiography. This study main objective was to determine whether measurements from RV focused views derived from three-dimensional (3D) echocardiography (3D-RV-focused) are closely related to measurements from magnetic resonance (CMR). A first cohort of 47 patients underwent 3D echocardiography and CMR imaging within 2 h of each other. A second cohort of 25 patients had repeat 3D echocardiography to determine the test-retest characteristics; and evaluate the bias associated with unfocused RV views. Tomographic views were extracted from the 3D dataset: RV focused views were obtained using the maximal RV diameter in the transverse plane, and unfocused views from a smaller transverse diameter enabling visualization of the tricuspid valve opening. Measures derived using the 3D-RV-focused view were strongly associated with CMR measurements. Among functional metrics, the strongest association was between RV fractional area change (RVFAC) and ejection fraction (RVEF) (r = 0.92) while tricuspid annular plane systolic excursion moderately correlated with RVEF (r = 0.47), all p < 0.001. Among RV size measures, the strongest association was found between RV end-systolic area (RVESA) and volume (r = 0.87, p < 0.001). RV unfocused views led on average to 10% underestimation of RVESA. The 3D-RV-focused method had acceptable test-retest characteristics with a coefficient of variation of 10% for RVESA and 11% for RVFAC. Deriving standardized RV focused views using 3D echocardiography strongly relates to CMR-derived measures and may improve reproducibility in RV 2D measurements.

Current Knowledge and Recent Advances of Right Ventricular Molecular Biology and Metabolism from Congenital Heart Disease to Chronic Pulmonary Hypertension

Studies about pulmonary hypertension and congenital heart diseases have introduced the concept of right ventricular remodeling leading these pathologies to a similar outcome: right ventricular failure. However right ventricular remodeling is also a physiological process that enables the normal fetal right ventricle to adapt at birth and gain its adult phenotype. The healthy mature right ventricle is exposed to low pulmonary vascular resistances and is compliant. However, in the setting of chronic pressure overload, as in pulmonary hypertension, or volume overload, as in congenital heart diseases, the right ventricle reverts back to a fetal phenotype to sustain its function. Mechanisms include angiogenic changes and concomitant increased metabolic activity to maintain energy production. Eventually, the remodeled right ventricle cannot resist the increased afterload, leading to right ventricular failure. After comparing the fetal and adult healthy right ventricles, we sought to review the main metabolic and cellular changes occurring in the setting of PH and CHD. Their association with RV function and potential impact on clinical practice will also be discussed.

Load Adaptability in Patients With Pulmonary Arterial Hypertension

Right ventricular (RV) adaptation to pressure overload is a major prognostic factor in patients with pulmonary arterial hypertension (PAH). The objectives were first to define the relation between RV adaptation and load using allometric modeling, then to compare the prognostic value of different indices of load adaptability in PAH. Both a derivation (n = 85) and a validation cohort (n = 200) were included. Load adaptability was assessed using 3 approaches: (1) surrogates of ventriculo-arterial coupling (e.g., RV area change/end-systolic area), (2) simple ratio of function and load (e.g., tricuspid annular plane systolic excursion/right ventricular systolic pressure), and (3) indices assessing the proportionality of adaptation using allometric pressure-function or size modeling. Proportional hazard modeling was used to compare the hazard ratio for the outcome of death or lung transplantation. The mean age of the derivation cohort was 44 ± 11 years, with 80% female and 74% in New York Heart Association class III or IV. Mean pulmonary vascular resistance index (PVRI) was 24 ± 11 with a wide distribution (1.6 to 57.5 WU/m²). Allometric relations were observed between PVRI and RV fractional area change (R² = 0.53, p < 0.001) and RV end-systolic area indexed to body surface area right ventricular end-systolic area index (RVESAI) (R² = 0.29, p < 0.001), allowing the derivation of simple ratiometric load-specific indices of RV adaptation. In right heart parameters, RVESAI was the strongest predictor of outcomes (hazard ratio per SD = 1.93, 95% confidence interval 1.37 to 2.75, p < 0.001). Although RVESAI/PVRI^0.35 provided small incremental discrimination on multivariate modeling, none of the load-adaptability indices provided stronger discrimination of outcome than simple RV adaptation metrics in either the derivation or the validation cohort. In conclusion, allometric modeling enables quantification of the proportionality of RV load adaptation but offers small incremental prognostic value to RV end-systolic dimension in PAH.

Right Heart End-Systolic Remodeling Index Strongly Predicts Outcomes in Pulmonary Arterial Hypertension: Comparison With Validated Models

BACKGROUND

Right ventricular (RV) end-systolic dimensions provide information on both size and function. We investigated whether an internally scaled index of end-systolic dimension is incremental to well-validated prognostic scores in pulmonary arterial hypertension.

METHODS AND RESULTS

From 2005 to 2014, 228 patients with pulmonary arterial hypertension were prospectively enrolled. RV end-systolic remodeling index (RVESRI) was defined by lateral length divided by septal height. The incremental values of RV free wall longitudinal strain and RVESRI to risk scores were determined. Mean age was 49±14 years, 78% were female, 33% had connective tissue disease, 52% were in New York Heart Association class ≥III, and mean pulmonary vascular resistance was 11.2±6.4 WU. RVESRI and right atrial area were strongly connected to the other right heart metrics. Three zones of adaptation (adapted, maladapted, and severely maladapted) were identified based on the RVESRI to RV systolic pressure relationship. During a mean follow-up of 3.9±2.4 years, the primary end point of death, transplant, or admission for heart failure was reached in 88 patients. RVESRI was incremental to risk prediction scores in pulmonary arterial hypertension, including the Registry to Evaluate Early and Long-Term PAH Disease Management score, the Pulmonary Hypertension Connection equation, and the Mayo Clinic model. Using multivariable analysis, New York Heart Association class III/IV, RVESRI, and log NT-proBNP (N-Terminal Pro-B-Type Natriuretic Peptide) were retained (χ², 62.2; P<0.0001). Changes in RVESRI at 1 year (n=203) were predictive of outcome; patients initiated on prostanoid therapy showed the greatest improvement in RVESRI. Among right heart metrics, RVESRI demonstrated the best test-retest characteristics.

CONCLUSIONS

RVESRI is a simple reproducible prognostic marker in patients with pulmonary arterial hypertension.