Right atrial and ventricular adaptation to chronic right ventricular pressure overload

Right ventricular diastolic adaptation to pressure overload in different rat strains

Different rat strains are used in various animal models of pulmonary hypertension and right ventricular (RV) failure. No systematic assessment has been made to test differences in RV response to pressure overload between rat strains. We compared RV adaptation to pulmonary trunk banding (PTB) in Wistar (W), Sprague Dawley (SD), and Fischer344 (F) rats by hemodynamic profiling focusing on diastolic function. Age-matched male rat weanlings were randomized to sham surgery (W-sham, n = 5; SD-sham, n = 4; F-sham, n = 4) or PTB (W-PTB, n = 8; SD-PTB, n = 8; F-PTB, n = 8). RV function was evaluated after 5 weeks by echocardiography, cardiac MRI, and invasive pressure-volume measurements. PTB caused RV failure and increased RV systolic pressures four-fold in all three PTB groups compared with sham. W- and SD-PTB had a 2.4-fold increase in RV end-systolic volume index compared with sham, while F-PTB rats were less affected. Diastolic and right atrial impairment were evident by increased RV end-diastolic elastance, filling pressure, and E/e' in PTB rats compared with sham, again F-PTB the least affected. In conclusions, PTB caused RV failure with signs of diastolic dysfunction. Despite a similar increase in RV systolic pressure, F-PTB rats showed less RV dilatation and a more preserved diastolic function compared with W- and SD-PTB.

Right Ventricle-Pulmonary Artery Coupling in Patients Undergoing Cardiac Interventions

PURPOSE OF REVIEW

This review aims to summarize the fundamentals of RV-PA coupling, its non-invasive means of measurement, and contemporary understanding of RV-PA coupling in cardiac surgery, cardiac interventions, and congenital heart disease.

RECENT FINDINGS

The need for more accessible clinical means of evaluation of RV-PA coupling has driven researchers to investigate surrogates using cardiac MRI, echocardiography, and right-sided pressure measurements in patients undergoing cardiac surgery/interventions, as well as patients with congenital heart disease. Recent research has aimed to validate these alternative means against the gold standard, as well as establish cut-off values predictive of morbidity and/or mortality. This emerging evidence lays the groundwork for identifying appropriate RV-PA coupling surrogates and integrating them into perioperative clinical practice.

Right Atrial Strain in Pediatric Pulmonary Hypertension-A Prospective Observational Study

Right ventricular (RV) afterload due to elevated pulmonary arterial (PA) pressure in pulmonary hypertension (PH) causes long-term right atrial (RA) remodeling and dysfunction. RA function has been shown to correlate with PA pressures and outcome in both adult and pediatric patients with PH. We studied the role of RA strain in estimating PA pressures in congenital heart disease (CHD)-associated PH. Children below 12 years undergoing elective repair of CHD with left-to-right shunts and echocardiographic evidence of PH were included. RA reservoir, conduit and contractile strain along with conventional measures of RV function and PA pressure were measured using transthoracic echocardiography after induction of anaesthesia. Pre-and post-repair invasive PA pressures were measured after surgical exposure. 51 children with a median age of 24 months (range 4-144 months) were included, most of whom were undergoing VSD closure. Contractile RA strain showed good correlation with pre-repair systolic PA pressure in mmHg (r = 0.59, 95%CI 0.37-0.75) or expressed as a percentage of SBP (r = 0.67, 95%CI 0.49-0.80). It also predicted persistent postoperative PH as well as pre-repair pulmonary artery acceleration time and right ventricular systolic pressure measured from tricuspid regurgitation jet. The trends of correlation observed suggest a possible prognostic role of RA strain in ACHD with PH and potential utility in its echocardiographic assessment. The observed findings merit deeper evaluation in larger cohorts.

Association of serum uric acid with right cardiac chamber remodeling assessed by cardiovascular magnetic resonance feature tracking in patients with connective tissue disease

Background

Right cardiac chamber remodeling is widespread in patients with connective tissue disease (CTD). Serum uric acid (SUA) is considered a potential independent risk factor for cardiovascular disease, and elevated SUA levels are often observed in patients with CTD. The correlation between SUA levels and right cardiac chamber remodeling remains unclear. This study investigated the association of SUA with right cardiac chamber remodeling as assessed by cardiac magnetic resonance feature-tracking (CMR-FT) in CTD patients.

Methods and results

In this cross-sectional study, a total of 104 CTD patients and 52 age- and sex-matched controls were consecutively recruited. All individuals underwent CMR imaging, and their SUA levels were recorded. The patients were divided into three subgroups based on the tertiles of SUA level in the present study. CMR-FT was used to evaluate the right atrial (RA) longitudinal strain and strain rate parameters as well as right ventricular (RV) global systolic peak strain and strain rate in longitudinal and circumferential directions for each subject. Univariable and multivariable linear regression analyses were used to explore the association of SUA with RV and RA strain parameters. Compared with the controls, the CTD patients showed significantly higher SUA levels but a lower RV global circumferential strain (GCS) and RA phasic strain parameters (all p < 0.05), except the RA booster strain rate. RV GCS remained impaired even in CTD patients with preserved RV ejection fraction. Among subgroups, the patients in the third tertile had significantly impaired RV longitudinal strain (GLS), RV GCS, and RA reservoir and conduit strain compared with those in the first tertile (all p < 0.05). The SUA levels were negatively correlated with RV GLS and RV GCS as well as with RA reservoir and conduit strain and strain rates (the absolute values of β were 0.250 to 0.293, all P < 0.05). In the multivariable linear regression analysis, the SUA level was still an independent determinant of RA conduit strain (β = -0.212, P = 0.035) and RV GCS (β = 0.207, P = 0.019).

Conclusion

SUA may be a potential risk factor of right cardiac chamber remodeling and is independently associated with impaired RA conduit strain and RV GCS in CTD patients.

Echocardiographic evaluation of right ventricular diastolic function in pulmonary hypertension

Background

Right ventricular (RV) diastolic dysfunction may be prognostic in pulmonary hypertension (PH). However, its assessment is complex and relies on conductance catheterisation. We aimed to evaluate echocardiography-based parameters as surrogates of RV diastolic function, provide validation against the gold standard, end-diastolic elastance (Eed), and define the prognostic impact of echocardiography-derived RV diastolic dysfunction.

Methods

Patients with suspected PH who underwent right heart catheterisation including conductance catheterisation were prospectively recruited. In this study population, an echocardiography-based RV diastolic function surrogate was derived. Survival analyses were performed in patients with precapillary PH in the Giessen PH Registry, with external validation in patients with pulmonary arterial hypertension at Sapienza University (Rome).

Results

In the derivation cohort (n=61), the early/late diastolic tricuspid inflow velocity ratio (E/A) and early tricuspid inflow velocity/early diastolic tricuspid annular velocity ratio (E/e') did not correlate with Eed (p>0.05). Receiver operating characteristic analysis revealed a large area under the curve (AUC) for the peak lateral tricuspid annulus systolic velocity/right atrial area index ratio (S'/RAAi) to detect elevated Eed (AUC 0.913, 95% confidence interval (CI) 0.839-0.986) and elevated end-diastolic pressure (AUC 0.848, 95% CI 0.699-0.998) with an optimal threshold of 0.81 m2·s-1·cm-1. Subgroup analyses demonstrated a large AUC in patients with preserved RV systolic function (AUC 0.963, 95% CI 0.882-1.000). Survival analyses confirmed the prognostic relevance of S'/RAAi in the Giessen PH Registry (n=225) and the external validation cohort (n=106).

Conclusions

Our study demonstrates the usefulness of echocardiography-derived S'/RAAi for noninvasive assessment of RV diastolic function and prognosis in PH.

Right Atrial Adaptation to Precapillary Pulmonary Hypertension: Pressure-Volume, Cardiomyocyte, and Histological Analysis

BACKGROUND

Precapillary pulmonary hypertension (precPH) patients have altered right atrial (RA) function and right ventricular (RV) diastolic stiffness.

OBJECTIVES

This study aimed to investigate RA function using pressure-volume (PV) loops, isolated cardiomyocyte, and histological analyses.

METHODS

RA PV loops were constructed in control subjects (n = 9) and precPH patients (n = 27) using magnetic resonance and catheterization data. RA stiffness (pressure rise during atrial filling) and right atrioventricular coupling index (RA minimal volume / RV end-diastolic volume) were compared in a larger cohort of patients with moderate (n = 39) or severe (n = 41) RV diastolic stiffness. Cardiomyocytes were isolated from RA tissue collected from control subjects (n = 6) and precPH patients (n = 9) undergoing surgery. Autopsy material was collected from control subjects (n = 6) and precPH patients (n = 4) to study RA hypertrophy, capillarization, and fibrosis.

RESULTS

RA PV loops showed 3 RA cardiac phases (reservoir, passive emptying, and contraction) with dilatation and elevated pressure in precPH. PrecPH patients with severe RV diastolic stiffness had increased RA stiffness and worse right atrioventricular coupling index. Cardiomyocyte cross-sectional area was increased 2- to 3-fold in precPH, but active tension generated by the sarcomeres was unaltered. There was no increase in passive tension of the cardiomyocytes, but end-stage precPH showed reduced number of capillaries per mm2 accompanied by interstitial and perivascular fibrosis.

CONCLUSIONS

RA PV loops show increased RA stiffness and suggest atrioventricular uncoupling in patients with severe RV diastolic stiffness. Isolated RA cardiomyocytes of precPH patients are hypertrophied, without intrinsic sarcomeric changes. In end-stage precPH, reduced capillary density is accompanied by interstitial and perivascular fibrosis.

Imaging the right atrium in pulmonary hypertension: A systematic review and meta-analysis

BACKGROUND

Right atrial (RA) imaging has emerged as a promising tool for the evaluation of patients with pulmonary hypertension (PH), albeit without systematic validation.

METHODS

PubMed, Web of Science and the Cochrane library were searched for studies investigating the prognostic value of RA imaging assessment in patients with PH from 2000 to June 2021 (PROSPERO Identifier: CRD42020212850). An inverse variance-weighted meta-analysis of univariable hazard ratios (HRs) was performed using a random effects model.

RESULTS

Thirty-five studies were included (3,476 patients with PH; 74% female, 86% pulmonary arterial hypertension). Risk of bias was low/moderate (Quality of Prognosis Studies checklist). RA area (HR 1.06; 95% confidence interval [CI] 1.04-1.08), RA indexed area (HR 1.09; 95% CI 1.04-1.14), RA peak longitudinal strain (PLS; HR 0.94; 95% CI 0.91-0.97) and RA total emptying fraction (HR 0.96; 95% CI 0.94-0.98) were significantly associated with combined end-points including death, clinical worsening and/or lung transplantation; RA volume and volume index showed marginal significant associations. RA area (HR 1.06; 95% CI 1.04-1.07), RA indexed area (HR 1.12; 95% CI 1.07-1.17) and RA PLS (HR 0.98; 95% CI 0.97-0.99) showed significant associations with mortality; RA total emptying fraction showed a marginal association.

CONCLUSIONS

Imaging-based RA assessment qualifies as a relevant prognostic marker in PH. RA area reliably predicts composite end-points and mortality, which underscores its clinical utility. RA PLS emerged as a promising imaging measure, but is currently limited by the number of studies and different acquisition methods.

Right ventricular size and function evaluated by various echocardiographic indices in dogs with pulmonary hypertension

BACKGROUND

Three-dimensional (3D) echocardiography and 2-dimensional (2D) strain measurements of the right ventricle (RV) are important indices in humans with pulmonary hypertension (PH) and need further evaluation in dogs with PH.

OBJECTIVES

To evaluate various RV size and function indices in dogs with PH and to examine differences between pre- and postcapillary PH.

ANIMALS

A total of 311 client-owned dogs: 100 dogs with PH, 31 with postcapillary and 69 with precapillary PH, and 211 healthy control dogs.

METHODS

Retro- and prospective, multicenter study. Size and function of the RV was determined using several indices, derived using dedicated RV software, including 3D RV end-diastolic volume (EDVn), end-systolic volume (ESVn), ejection fraction, 2D global and free wall RV longitudinal strain (RVLS), end-diastolic area, end-systolic area, fractional area change, tricuspid annular plane systolic excursion, and tissue Doppler imaging-derived systolic myocardial velocity of the lateral tricuspid annulus (S'n).

RESULTS

The EDVn (1.8 vs 2.5 mL/kg^0.942 , P < .01) and ESVn (0.8 vs 1.2 mL/kg^0.962 , P < .001) were significantly larger in the PH group compared to healthy controls. Free wall RVLS was decreased in dogs with severe PH compared to controls (-24% vs -29.6%, P < .001). Dogs with precapillary PH had worse RV systolic function than dogs with postcapillary PH.

CONCLUSION

Three-dimensional echocardiography of the RV is a promising tool to detect RV changes in dogs with PH. Also, 2D strain measurements are able to detect decreased RV function and offer several advantages compared to conventional indices.

Right atrial function early after tetralogy of Fallot repair

Diastolic dysfunction after repair for Tetralogy of Fallot (TOF) is associated with adverse long-term outcomes. Right atrial (RA) mechanics as a proxy of right ventricular (RV) diastolic function in the early post-operative period after surgical repair for TOF has not been reported. We sought to evaluate RA and RV strain prior to hospital discharge after TOF repair and to identify important patient factors associated with strain using a machine learning method. Single center retrospective cohort study of TOF patients undergoing surgical repair, with analysis of RA and RV strain from pre-and post-operative echocardiograms. RA function was assessed by the peak RA strain, systolic RA strain rate, early diastolic RA strain rate and RA emptying fraction. RV systolic function was measured by global longitudinal strain. Pre- and post-operative values were compared using Wilcoxon rank sum test. Gradient boosted machine (GBM) models were used to identify the most important predictors of post-operative strain. In total, 153 patients were enrolled, median age at TOF repair 3.5 months (25th-75th percentile: 2.2- 5.2), mostly male (67%), and White (64.1%). From pre-to post-operative period, there was significant worsening in all RA parameters and in RV strain. GBM models identified patient, anatomic, and surgical factors that were strong predictors of post-operative RA and RV strain. These factors included pulmonary valve and branch pulmonary artery Z scores, birth weight, gestational age and age at surgery, pre-operative RV fractional area change and oxygen saturation, type of outflow tract repair, duration of cardiopulmonary bypass, and early post-operative partial arterial pressure of oxygen. There is significant worsening in RA and RV strain early after TOF repair, indicating early alteration in diastolic and systolic function after surgery. Several patient and operative factors influence post-operative RV function. Most of the factors described are not readily modifiable, however they may inform pre-operative risk-stratification. The clinical application of RA strain and the prognostic implication of these early changes merit further study.

Prediction of right ventricular failure after left ventricular assist device implantation: role of vasodilator challenge

AIMS

Pulmonary artery pulsatility index (PAPi) is an indicator of right ventricular (RV) function and an independent predictor of right ventricular failure (RVF) following left ventricular assist device (LVAD) implantation. Administration of vasodilator challenge during right heart catheterization (RHC) could reduce RV workload allowing a better assessment of its functional reserve.

METHODS AND RESULTS

Patients undergoing LVAD implantation at our Institution between May 2013 and August 2021 were enrolled. Only patients who had undergone RHC and vasodilator challenge with sodium nitroprusside were analyzed. We collected all available clinical, instrumental, and haemodynamic parameters, at baseline and after nitroprusside infusion and evaluated potential associations with post-LVAD RVF. Of the 54 patients analyzed, 19 (35%) developed RVF after LVAD implantation. Fractional area change (FAC) (OR: 0.647, CI: 0.481-0.871; P = 0.004), pulmonary artery systolic pressure (PASP) (OR: 0.856, CI: 0.761-0.964; P = 0.010), and post-sodium nitroprusside (NTP) PAPi (OR: 0.218, CI: 0.073-0.653; P = 0.006) were independent predictors of post-LVAD RVF. The model combining FAC, PASP, and post-NTP PAPi demonstrated a predictive accuracy of 90.7%. Addition of post-NTP PAPi significantly increased the predictive accuracy of the European Registry for Patients with Mechanical Circulatory Support right-sided heart failure risk score [79.4 vs. 70.4%; area under the curve (AUC): 0.841 vs. 0.724, P = 0.022] and the CRITT score (79.6% vs. 74%; AUC: 0.861 vs. 0.767 P = 0.033).

CONCLUSION

Post-NTP PAPi has observed to be an independent predictor of RVF following LVAD implantation. Dynamic assessment of PAPi using a vasodilator challenge may represent a method of testing RV functional reserve in candidates for LVAD implantation. Larger and prospective studies are needed to confirm this hypothesis.

Right ventricular performance in patients with heart failure with mildly reduced ejection fraction: the forgotten ventricle

Right ventricular (RV) function is a major determinant of prognosis and adverse outcomes in patients with heart failure (HF). It is largely unknown if HF with mildly reduced ejection fraction (HFmrEF) patients have some special characteristics in RV function (RVF) that may distinguish them from HF with reduced or preserved ejection fraction (HFrEF or HFpEF) patients. Standard echocardiography was performed to estimate RVF [tricuspid annular systolic velocity (TDSV), plane systolic excursion (TAPSE), TAPSE to pulmonary artery systolic pressure (TAPSE/PASP) and RV myocardial performance index (MPI-TEI index)] in a cross-sectional study. In 306 participants, the RV systolic function evaluated with TAPSE and TDSV was impaired in 39.1 and 24.2%, respectively. TAPSE, TAPSE/PASP and TDSV were lower in HFmrEF compared with HFpEF and higher compared with HFrEF (p < 0.001 for among-groups comparison). RV diastolic dysfunction varied between 12.6 and 43.8% depending on the echocardiographic parameter. Diastolic RVF determined by tricuspid inflow E/A wave ratio (Et/At) was impaired in less patients with HFmrEF compared with those with HFpEF or HFrEF (25.9% vs 48.4% vs 56.3%; p = 0.030, respectively). RV diastolic dysfunction by et'/at' (tissue Doppler tricuspid valve annulus e' and a' waves) was impaired in less patients with HFmrEF compared with HFrEF (11.8% vs 33.3%; p = 0.019). A multivariate regression analysis revealed a significant association between RV and LV systolic dysfunction. The present study shows a high prevalence of RV dysfunction in HFmrEF patients. Study findings provides some new insights on RV and LV systolic dysfunction coupling whereas RV diastolic dysfunction was not dependent on LV systolic dysfunction.

Imaging assessment of the right atrium: anatomy and function

The right atrium (RA) is the cardiac chamber that has been least well studied. Due to recent advances in interventional cardiology, the need for greater understanding of the RA anatomy and physiology has garnered significant attention. In this article, we review how a comprehensive assessment of RA dimensions and function using either echocardiography, cardiac computed tomography, and magnetic resonance imaging may be used as a first step towards a better understanding of RA pathophysiology. The recently published normative data on RA size and function will likely shed light on RA atrial remodelling in atrial fibrillation (AF), which is a complex phenomenon that occurs in both atria but has only been studied in depth in the left atrium. Changes in RA structure and function have prognostic implications in pulmonary hypertension (PH), where the increased right ventricular (RV) afterload first induces RV remodelling, predominantly characterized by hypertrophy. As PH progresses, RV dysfunction and dilatation may begin and eventually lead to RV failure. Thereafter, RV overload and increased RV stiffness may lead to a proportional increase in RA pressure. This manuscript provides an in-depth review of RA anatomy, function, and haemodynamics with particular emphasis on the changes in structure and function that occur in AF, tricuspid regurgitation, and PH.

MRI Feature Tracking Strain in Pulmonary Hypertension: Utility of Combined Left Atrial Volumetric and Deformation Assessment in Distinguishing Post- From Pre-capillary Physiology

Aims

Pulmonary hypertension (PH) is dichotomized into pre- and post-capillary physiology by invasive catheterization. Imaging, particularly strain assessment, may aid in classification and be helpful with ambiguous hemodynamics. We sought to define cardiac MRI (CMR) feature tracking biatrial peak reservoir and biventricular peak systolic strain in pre- and post-capillary PH and examine the performance of peak left atrial strain in distinguishing the 2 groups compared to TTE.

Methods and Results

Retrospective cross-sectional study from 1 Jan 2015 to 31 Dec 2020; 48 patients (22 pre- and 26 post-capillary) were included with contemporaneous TTE, CMR and catheterization. Mean pulmonary artery pressures were higher in the pre-capillary cohort (55 ± 14 vs. 42 ± 9 mmHg; p &lt; 0.001) as was pulmonary vascular resistance (median 11.7 vs. 3.7 WU; p &lt; 0.001). Post-capillary patients had significantly larger left atria (60 ± 22 vs. 25 ± 9 ml/m2; p &lt; 0.001). There was no difference in right atrial volumes between groups (60 ± 21 vs. 61 ± 29 ml/m2; p = 0.694), however peak RA strain was lower in post-capillary PH patients (8.9 ± 5.5 vs. 18.8 ± 7.0%; p &lt; 0.001). In the post-capillary group, there was commensurately severe peak strain impairment in both atria (LA strain 9.0 ± 5.8%, RA strain 8.9 ± 5.5%). CMR LAVi and peak LA strain had a multivariate AUC of 0.98 (95% CI 0.89–1.00; p &lt; 0.001) for post-capillary PH diagnosis which was superior to TTE.

Conclusion

CMR volumetric and deformation assessment of the left atrium can highly accurately distinguish post- from pre-capillary PH.

The Prognostic Value of Right Atrial and Right Ventricular Functional Parameters in Systemic Sclerosis

Introduction

Right ventricular (RV) function is of particular importance in systemic sclerosis (SSc), since common SSc complications, such as interstitial lung disease and pulmonary hypertension may affect RV afterload. Cardiovascular magnetic resonance (CMR) is the gold standard for measuring RV function. CMR-derived RV and right atrial (RA) strain is a promising tool to detect subtle changes in RV function, and might have incremental value, however, prognostic data is lacking. Therefore, the aim of this study was to evaluate the prognostic value of RA and RV strain in SSc.

Methods

In this retrospective study, performed at two Dutch hospitals, consecutive SSc patients who underwent CMR were included. RV longitudinal strain (LS) and RA strain were measured. Unadjusted cox proportional hazard regression analysis and likelihood ratio tests were used to evaluate the association and incremental value of strain parameters with all-cause mortality.

Results

A total of 100 patients (median age 54 [46–64] years, 42% male) were included. Twenty-four patients (24%) died during a follow-up of 3.1 [1.8–5.2] years. RA reservoir [Hazard Ratio (HR) = 0.95, 95% CI 0.91–0.99, p = 0.009] and conduit strain (HR = 0.93, 95% CI 0.88–0.98, p = 0.008) were univariable predictors of all-cause mortality, while RV LS and RA booster strain were not. RA conduit strain proved to be of incremental value to sex, atrial fibrillation, NYHA class, RA maximum volume indexed, and late gadolinium enhancement (p < 0.05 for all).

Conclusion

RA reservoir and conduit strain are predictors of all-cause mortality in SSc patients, whereas RV LS is not. In addition, RA conduit strain showed incremental prognostic value to all evaluated clinical and imaging parameters. Therefore, RA conduit strain may be a useful prognostic marker in SSc patients.

Right Atrial Strain in Preterm Infants With a History of Bronchopulmonary Dysplasia

BACKGROUND

Few studies have utilized right atrial (RA) strain to evaluate right ventricular (RV) diastolic dysfunction in preterm infants with bronchopulmonary dysplasia (BPD). We aimed to evaluate the associations of RA strain with BPD severity and respiratory outcomes in preterm infants with BPD.

METHODS

We retrospectively studied 153 infants with BPD born before 32 weeks of gestational age at CHA Bundang Medical Center. Peak longitudinal right atrial strain (PLRAS) was obtained using velocity vector imaging and compared among infants across BPD severity. Conventional echocardiographic parameters and clinical characteristics were also evaluated.

RESULTS

In infants with severe BPD, mean gestational age (27.4 ± 2.1 weeks) and mean birth weight (971.3 ± 305.8 g) were significantly smaller than in those with mild BPD (30.0 ± 0.9 weeks, 1,237.3 ± 132.2 g) and moderate BPD (29.6 ± 1.3 weeks, 1,203.2 ± 214.4 g). PLRAS was significantly lower in infants with severe BPD (26.3 ± 10.1%) than in those in the moderate BPD group (32.4 ± 10.9%) or mild BPD group (31.9 ± 8.3%). Tricuspid E/e′ and maximum RA volume index were similar across BPD severity. A decrease in PLRAS was significantly correlated with increased duration of mechanical ventilation duration; however, tricuspid E/e′ and maximum RA volume index were not.

CONCLUSIONS

Evaluating PLRAS with other parameters in infants with BPD might detect RV diastolic dysfunction. Longer follow-up and larger study populations may elucidate the association between PLRAS and respiratory outcomes in infants with BPD.

Acute right ventricular failure associated with pulmonary hypertension in pediatrics: understanding the hemodynamic profiles

Pulmonary hypertension (PHTN) is a common pathology in pediatrics, arising from a diverse array of etiologies and manifesting in equally diverse patient populations. The inpatient management of these infants and children may be complicated by dynamic and at times severe increases in pulmonary vascular resistance (PVR) and right ventricular (RV) afterload. Yet absent are cognitively accessible heuristics in the field whereby providers can reconcile the various clinical manifestations they observe with an understanding of the cardiac physiology at play, and therefore, appropriate physiology-driven interventions. Described herein is a framework for understanding the pathophysiology of four clinical phenotypes which are driven by two echocardiographic patient characteristics: the presence or absence of an atrial communication and the capacity of the right ventricle to maintain ventricular-vascular coupling. Application of this paradigm may facilitate accurate interpretation of observed clinical data, and alignment of treatment strategies with the underlying pathophysiology.

Clinical Relevance of Right Atrial Functional Response to Treatment in Pulmonary Arterial Hypertension

Background: Right atrial (RA) function has emerged as an important determinant of outcome in pulmonary arterial hypertension (PAH). However, studies exploring RA function after initiation of specific pulmonary vascular treatment and its association with outcome in patients with incident PAH are lacking. Methods: RA peak longitudinal strain (PLS), passive strain (PS), and peak active contraction strain (PACS) were retrospectively assessed in 56 treatment-naïve patients with PAH at baseline and during follow-up after initiation of specific monotherapy or combination therapy. Patients were grouped according to their individual RA functional response to treatment, based on change from baseline (Δ): worsened (first Δ-tertile), stable (second Δ-tertile), and improved (third Δ-tertile). The Spearman's rho correlation and linear regression analysis were used to determine associations. Time to clinical worsening (defined as deterioration of functional class or 6-min walking distance, disease-related hospital admission, or death) was measured from the follow-up assessment. The association of RA functional treatment response with time to clinical worsening was assessed using the Kaplan-Meier and the Cox regression analyses. Results: Median (interquartile range) time to echocardiographic follow-up was 11 (9-12) months. Of the 56 patients, 37 patients (66%) received specific dual or triple combination therapy. Δ RA PLS during follow-up was significantly associated with changes in key hemodynamic and echocardiographic parameters. The change of pulmonary vascular resistance, right ventricular (RV) end-systolic area, and global longitudinal strain were independently associated with Δ RA PLS. The median time to clinical worsening after echocardiographic follow-up was 6 (2-14) months [17 events (30%)]. In the multivariate Cox regression analysis, worsening of RA PLS was significantly associated with clinical deterioration (hazard ratio: 4.87; 95% CI: 1.26-18.76; p = 0.022). Patients with worsened RA PLS had a significantly poorer prognosis than those with stable or improved RA PLS (log-rank p = 0.012). By contrast, PS and PACS did not yield significant prognostic information. Conclusion: Treatment-naïve patients with PAH may show different RA functional response patterns to PAH therapy. These functional patterns are significantly associated with clinically relevant outcome measures. Improvements of RA function are driven by reductions of afterload, RV remodeling, and RV dysfunction.

Right ventricular systolic and diastolic function assessed by two-dimensional speckle tracking echocardiography in dogs with myxomatous mitral valve disease

Pulmonary hypertension (PH) is a common comorbidity in dogs with myxomatous mitral valve disease (MMVD), and can induce various changes in the right heart, such as right ventricular (RV) hypertrophy, dilatation, and dysfunction. We hypothesized that RV function, not only systolic function but also diastolic function, could be worsened with PH progression. We aimed to compare RV systolic and diastolic function in dogs with MMVD. Twenty healthy dogs and sixty-eight dogs with MMVD were enrolled. Dogs with MMVD were classified into the probability of PH. Two-dimensional and Doppler echocardiographic indices for right heart and two-dimensional speckle tracking echocardiography indices were measured. The morphological indicators of the right heart were significantly higher only in the high probability of PH group. The RV strain, early-diastolic and systolic strain rates were significantly lower in the high probability of PH group than those in the low and intermediate probability of PH groups. Multivariate analysis showed that increased RV internal dimension normalized by body weight and RV myocardial performance index were significantly associated with the presence of right-sided congestive heart failure. Speckle tracking echocardiography-derived RV systolic and diastolic function were activated in the low and intermediate probability of PH groups. However, dogs with high probability of PH showed RV myocardial dysfunction and dilatation. Increased RV myocardial performance index and end-diastolic RV internal dimension normalized by body weight were significantly associated with the presence of right-sided congestive heart failure in dogs with MMVD.

Does pulmonary artery pulsatility index predict mortality in pulmonary arterial hypertension?

Aims

Pulmonary artery pulsatility index (PAPi), defined as [(pulmonary artery systolic pressure − diastolic pulmonary artery pressure)/mean right atrial pressure], is a novel haemodynamic index that predicts right ventricular failure after myocardial infarction and left ventricular assist device implantation. We analysed if a low PAPi is associated with death in our 14 ‐ ​year pulmonary arterial hypertension (PAH) registry.

Methods

Consecutive patients with newly diagnosed PAH and complete haemodynamic data were prospectively enrolled into our standing registry between January 2003 and December 2016. PAPi was calculated from baseline invasive right heart catheterization data. A prognostic cut‐off value was determined with a decision tree. Baseline characteristics of ‘high’ and ‘low’ PAPi groups based on this cut‐off were compared, as well as odds of death and time‐to‐death.

Results

One hundred and two patients were included. Mean age was 53 years, and 77% were women. Our multi‐ethnic cohort was 64% Chinese, 23% Malay, and 10% Indian. The aetiologies were idiopathic (33%), connective tissue disease (31%), congenital heart disease (24%), and others (12%). The low PAPi group (<5.3) had a greater age (56 years vs. 49 years), lower pulmonary artery systolic pressure (71 mmHg vs. 85 mmHg), and higher mean right atrial pressure (14 mmHg vs. 6 mmHg). Mortality risk was higher in the low PAPi group (adjusted odds ratio: 2.98 and adjusted hazard ratio: 2.23). Mean right atrial pressure was the strongest predictor (hazard ratio 1.114, P = 0.009) when components of PAPi were analysed.

Conclusions

Pulmonary artery pulsatility index was found to be predictive of mortality in PAH and may be a valuable marker for risk stratification. Its prognostic strength may be driven by mean right atrial pressure.

Radiofrequency Catheter Ablation of Supraventricular Tachycardia in Patients With Pulmonary Hypertension: Feasibility and Long-Term Outcome

Background

Supraventricular tachycardia (SVT) occurs commonly and is strongly correlated with clinical deterioration in patients with pulmonary hypertension (PH). This study aimed to investigate the feasibility and long-term outcome of radiofrequency catheter ablation (RFCA) in PH patients with SVT.

Materials and Methods

Consecutive PH patients with SVT who were scheduled to undergo electrophysiological study and RFCA between September 2010 and July 2019 were included. The acute results and long-term success of RFCA were assessed after the procedure.

Results

In total, 71 PH patients with 76 episodes of SVT were analyzed. Cavotricuspid isthmus-dependent atrial flutter (n = 33, 43.5%) was the most common SVT type, followed by atrioventricular nodal reentrant tachycardia (n = 16, 21.1%). Of the 71 patients, 60 (84.5%) underwent successful electrophysiological study and were subsequently treated by RFCA. Among them, acute sinus rhythm was restored in 54 (90.0%) patients, and procedure-related complications were observed in 4 (6.7%) patients. Univariate logistic regression analysis showed that cavotricuspid isthmus-independent atrial flutter [odds ratio (OR) 25.00, 95% confidence interval (CI) 3.45–180.98, p = 0.001] and wider pulmonary artery diameter (OR 1.19, 95% CI 1.03–1.38; p = 0.016) were associated with RFCA failure. During a median follow-up of 36 (range, 3–108) months, 7 patients with atrial flutter experienced recurrence, yielding a 78.3% 3-year success rate for RFCA treatment.

Conclusion

The findings suggest that RFCA of SVT in PH patients is feasible and has a good long-term success rate. Cavotricuspid isthmus-independent atrial flutter and a wider PAD could increase the risk for ablation failure.

Current Understanding of the Right Ventricle Structure and Function in Pulmonary Arterial Hypertension

Pulmonary arterial hypertension (PAH) is a disease resulting in increased right ventricular (RV) afterload and RV remodeling. PAH results in altered RV structure and function at different scales from organ-level hemodynamics to tissue-level biomechanical properties, fiber-level architecture, and cardiomyocyte-level contractility. Biomechanical analysis of RV pathophysiology has drawn significant attention over the past years and recent work has found a close link between RV biomechanics and physiological function. Building upon previously developed techniques, biomechanical studies have employed multi-scale analysis frameworks to investigate the underlying mechanisms of RV remodeling in PAH and effects of potential therapeutic interventions on these mechanisms. In this review, we discuss the current understanding of RV structure and function in PAH, highlighting the findings from recent studies on the biomechanics of RV remodeling at organ, tissue, fiber, and cellular levels. Recent progress in understanding the underlying mechanisms of RV remodeling in PAH, and effects of potential therapeutics, will be highlighted from a biomechanical perspective. The clinical relevance of RV biomechanics in PAH will be discussed, followed by addressing the current knowledge gaps and providing suggested directions for future research.

The Indices of Cardiovascular Magnetic Resonance Derived Atrial Dynamics May Improve the Contemporary Risk Stratification Algorithms in Children with Hypertrophic Cardiomyopathy

Introduction: The most efficient risk stratification algorithms are expected to deliver robust and indefectible identification of high-risk children with hypertrophic cardiomyopathy (HCM). Here we compare algorithms for risk stratification in primary prevention in HCM children and investigate whether novel indices of biatrial performance improve these algorithms. Methods and Results: The endpoints were defined as sudden cardiac death, resuscitated cardiac arrest, or appropriate implantable cardioverter-defibrillator discharge. We examined the prognostic utility of classic American College of Cardiology/American Heart Association (ACC/AHA) risk factors, the novel HCM Risk-Kids score and the combination of these with indices of biatrial dynamics. The study consisted of 55 HCM children (mean age 12.5 ± 4.6 years, 69.1% males); seven had endpoints (four deaths, three appropriate ICD discharges). A strong trend (DeLong p = 0.08) was observed towards better endpoint identification performance of the HCM Risk-Kids Model compared to the ACC/AHA strategy. Adding the atrial conduit function component significantly improved the prediction capabilities of the AHA/ACC Model (DeLong p = 0.01) and HCM Risk-Kids algorithm (DeLong p = 0.04). Conclusions: The new HCM Risk-Kids individualised algorithm and score was capable of identifying high-risk children with very good accuracy. The inclusion of one of the atrial dynamic indices improved both risk stratification strategies.

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.

Treatment of right ventricular dysfunction and heart failure in pulmonary arterial hypertension

Right heart dysfunction and failure is the principal determinant of adverse outcomes in patients with pulmonary arterial hypertension (PAH). In addition to right ventricular (RV) dysfunction, systemic congestion, increased afterload and impaired myocardial contractility play an important role in the pathophysiology of RV failure. The behavior of the RV in response to the hemodynamic overload is primarily modulated by the ventricular interaction and its coupling to the pulmonary circulation. The presentation can be acute with hemodynamic instability and shock or chronic producing symptoms of systemic venous congestion and low cardiac output. The prognostic factors associated with poor outcomes in hospitalized patients include systemic hypotension, hyponatremia, severe tricuspid insufficiency, inotropic support use and the presence of pericardial effusion. Effective therapeutic management strategies involve identification and effective treatment of the triggering factors, improving cardiopulmonary hemodynamics by optimization of volume to improve diastolic ventricular interactions, improving contractility by use of inotropes, and reducing afterload by use of drugs targeting pulmonary circulation. The medical therapies approved for PAH act primarily on the pulmonary vasculature with secondary effects on the right ventricle. Mechanical circulatory support as a bridge to transplantation has also gained traction in medically refractory cases. The current review was undertaken to summarize recent insights into the evaluation and treatment of RV dysfunction and failure attributable to PAH.

Association between right atrial area measured by echocardiography and prognosis among pulmonary arterial hypertension: a systematic review and meta-analysis

OBJECTIVE

The purpose of this meta-analysis was to evaluate the association between enlarged right atrial area (RAA), as measured by echocardiography, and prognosis of patients with pulmonary arterial hypertension (PAH).

DESIGN

Systematic review and meta-analysis.

DATA SOURCES

To identify potential publications, a comprehensive literature search through MEDLINE, the Cochrane database and the Embase database was performed up to December 2019.

ELIGIBILITY CRITERIA FOR SELECTING STUDIES

Studies were included if they reported Cox regression based-HRs with 95% CIs for all-cause mortality or composite endpoint consisting of death and PAH-related events for echocardiography measurements of the RAA or the right atrial area index (RAAI) in patients with PAH.

DATA EXTRACTION AND SYNTHESIS

The unadjusted HR with 95% CI was extracted for the final pooled analysis. A random-effects model was used to determine the value of RAA/RAAI in the prognosis of patients with PAH. The data heterogeneity among the studies was estimated by the I² statistic and the Cochran Q-statistic.

RESULTS

Twelve studies with a total of 1085 patients with PAH were finally included in the meta-analysis. These studies had a mean follow-up time ranging from 9.2 months to 5.0 years. Their findings showed that patients with PAH with enlarged RAA/RAAI were associated with poor prognosis. The risk of all-cause mortality in patients with PAH was found to statistically increase by 50% for every 5-unit increase in RAA/RAAI (HR 1.50, 95% CI 1.28 to 1.75, p<0.001). Similarly, the risk of the composite endpoint also significantly increased by 53% for every 5-unit increase in RAA/RAAI (HR 1.53, 95% CI 1.23 to 1.89, p<0.001). Subgroup analyses in which the patients were stratified by RAA and RAAI were consistent with the main results.

CONCLUSION

The meta-analysis suggested that enlarged RAA/RAAI were associated with increased risk of poor prognosis in patients with PAH.

Establishment of adult right ventricle failure in ovine using a graded, animal-specific pulmonary artery constriction model

BACKGROUND

Right ventricle failure (RVF) is associated with serious cardiac and pulmonary diseases that contribute significantly to the morbidity and mortality of patients. Currently, the mechanisms of RVF are not fully understood and it is partly due to the lack of large animal models in adult RVF. In this study, we aim to establish a model of RVF in adult ovine and examine the structure and function relations in the RV.

METHODS

RV pressure overload was induced in adult male sheep by revised pulmonary artery constriction (PAC). Briefly, an adjustable hydraulic occluder was placed around the main pulmonary artery trunk. Then, repeated saline injection was performed at weeks 0, 1, and 4, where the amount of saline was determined in an animal-specific manner. Healthy, age-matched male sheep were used as additional controls. Echocardiography was performed bi-weekly and on week 11 post-PAC, hemodynamic and biological measurements were obtained.

RESULTS

This PAC methodology resulted in a marked increase in RV systolic pressure and decreases in stroke volume and tricuspid annular plane systolic excursion, indicating signs of RVF. Significant increases in RV chamber size, wall thickness, and Fulton's index were observed. Cardiomyocyte hypertrophy and collagen accumulation (particularly type III collagen) were evident, and these structural changes were correlated with RV dysfunction.

CONCLUSION

In summary, the animal-specific, repeated PAC provided a robust approach to induce adult RVF, and this ovine model will offer a useful tool to study the progression and treatment of adult RVF that is translatable to human diseases.

Decoupling Between Diastolic Pulmonary Artery and Pulmonary Capillary Wedge Pressures Is Associated With Right Ventricular Dysfunction and Hemocompatibility-Related Adverse Events in Patients With Left Ventricular Assist Devices

Background

Decoupling between diastolic pulmonary artery pressure and pulmonary capillary wedge pressure is an index of pulmonary vascular damage. This study assessed the impact of decoupling on right heart function and hemocompatibility‐related adverse events.

Methods and Results

In this prospective study, patients underwent invasive hemodynamic tests following left ventricular assist device implantation. Decoupling was defined as a difference of >5 mm Hg between diastolic pulmonary artery pressure and pulmonary capillary wedge pressure. Among 92 patients with left ventricular assist devices (median age, 61 years; 57% male), 44 patients (48%) had decoupling. Right heart function and size by echocardiographic assessment worsened during a 1‐year observational period in the decoupling group as compared with the control group (P<0.05). The decoupling group had significantly lower 1‐year freedom from any hemocompatibility‐related adverse events (49% versus 79%; P=0.005), as well as a higher hemocompatibility score (2.14 versus 0.67; P=0.004). The scoring system depicts the severity of hemocompatibility‐related adverse events using 4 escalating tiers. Increased tier I scores (1–2 gastrointestinal bleedings or medically managed pump thrombosis; P=0.027) and tier IIIB scores (disabling stroke or hemocompatibility‐related adverse event–related death; P=0.041) occurred more frequently in the decoupling group.

Conclusions

The presence of decoupling between diastolic pulmonary artery pressure and pulmonary capillary wedge pressure was associated with worsening of right heart function and hemocompatibility‐related adverse events in patients with left ventricular assist devices.

Serum parathyroid hormone levels in patients with chronic right heart failure

Parathyroid hormone (PTH) is a novel cardiovascular biomarker which is particularly useful for detection and assessment of heart failure (HF). However, previous studies examining PTH in heart failure have primarily focused on left HF; thus, the relationship between PTH and right HF remains unclear. The aim of the present study was to evaluate the serum PTH levels in patients with chronic right HF. A total of 154 patients with chronic right HF were enrolled in the present study. A binary logistic regression analysis model was used to assess the independent predictive value of PTH levels in chronic right HF. Partial correlative analysis was used to demonstrate the relevance of PTH levels on the parameters of assessment of right heart function. A multiple linear regression analysis model was used to evaluate the independent factors of PTH levels in patients with right HF. The results showed that the serum PTH levels in the right HF group were significantly higher compared with the control group. After adjusting for predictors of right HF, serum PTH levels were associated with right HF with an odds ratio of 1.066 (95% confidence interval: 1.030-1.102, P<0.001. Serum PTH levels were independently correlated with plasma N-terminal pro-B-type natriuretic peptide levels, right ventricular end-diastolic diameter and severity of lower extremity edema (all P<0.05). Therefore, based on the results of the present study, PTH may be a useful biomarker for detection and assessment of right HF.

Right ventricular function correlates of right atrial strain in pulmonary hypertension: a combined cardiac magnetic resonance and conductance catheter study

The functional relevance of right atrial (RA) function in pulmonary hypertension (PH) remains incompletely understood. The purpose of this study was to explore the correlation of cardiac magnetic resonance (CMR) feature tracking-derived RA phasic function with invasively measured pressure-volume (P-V) loop-derived right ventricular (RV) end-diastolic elastance ( Eed) and RV-arterial coupling [ratio of end-systolic elastance to arterial elastance ( Ees/ Ea)]. In 54 patients with severe PH, CMR was performed within 24 h of diagnostic right heart catheterization and P-V measurements. RA phasic function was assessed by CMR imaging of RA reservoir, passive, and active strain. The association of RA phasic function with indexes of RV function was evaluated by Spearman’s rank correlation and linear regression analyses. Median [interquartile range] RA reservoir strain, passive strain, and active strain were 19.5% [11.0–24.5], 7.0% [4.0–12.0], and 13.0% [7.0–18.5], respectively. Ees/ Ea was 0.73 [0.48–1.08], and Eed was 0.14 mmHg/mL [0.05–0.22]. RV diastolic impairment [RV end-diastolic pressure (EDP) and Eed] was correlated with RA phasic function, but Ea and Ees were not. In addition, RA phasic function was correlated with inferior vena cava diameter. In multivariate linear regression analysis, adjusting for key P-V loop indexes, Eed and EDP remained significantly associated with RA phasic function. We conclude that RA phasic function is altered in relation to impaired diastolic function of the chronically overloaded right ventricle and contributes to backward venous flow and systemic congestion. These results call for more attention to RA function in the management of patients with PH.

NEW & NOTEWORTHY There is growing awareness of the importance of the right atrial (RA)-right ventricular (RV) axis in pulmonary hypertension (PH). Our results uncover alterations in RA phasic function that are related to depressed RV lusitropic function and contribute to backward venous return and systemic congestion in chronic RV overload. Assessment of RA function should be part of the management and follow-up of patients with PH.

Clinical Utility and Prognostic Value of Right Atrial Function in Pulmonary Hypertension

Background Although right atrial (RA) enlargement is an established marker for adverse outcomes, the prognostic importance of RA dysfunction independent of RA size in pulmonary arterial hypertension is not known. Methods and Results Study subjects with pulmonary arterial hypertension were prospectively enrolled from 2010 to 2014. RA function was measured using RA speckle-tracking longitudinal strain and strain rate (SR) during each phase of the cardiac cycle: (1) RA reservoir (peak longitudinal strain, peak systolic SR), (2) RA conduit (peak early diastolic SR), and (3) RA active contraction (peak active contraction strain, peak contraction SR). The primary outcome was a composite of time to hospitalization or death assessed on follow-up. A total of 63 subjects had complete echocardiographic data. Of these, 91% were females, and the mean age was 58±12 years. During the follow-up period (range: 1-58 months), 39 were hospitalized or had died. After multivariable adjustment for age, sex, and left atrial size, peak longitudinal strain, peak active contraction strain, and peak early diastolic SR were significantly associated with increased risk of the composite outcome ( P=0.0005, P=0.0167, and P=0.0054, respectively). Conclusions RA dysfunction independently predicts mortality and hospitalizations in patients with pulmonary arterial hypertension.

Animal Models of Repaired Tetralogy of Fallot: Current Applications and Future Perspectives

Tetralogy of Fallot is the most common cyanotic congenital heart disease. Despite ongoing improvements in the initial surgical repair, there are lingering concerns regarding the long-term outcomes that may be complicated by right ventricular dysfunction, right ventricular dyssynchrony, and sudden cardiac death. The mechanisms leading to these late complications remain incompletely understood. Experimental animal models have been developed as preclinical steps to gain better insight into the pathophysiology of diseases and to develop new therapeutic strategies. This article summarizes the various types of experimental animal models of repaired tetralogy of Fallot published to date in the literature, with the aim of achieving a greater understanding of the deleterious mechanisms that may lead to these known late and sometimes lethal complications. In addition to analysing the type of animals that can be used according to a given study's objectives, needs, and constraints, the present review also evaluates the type of dysfunction that can be reproduced in our model according to the research objectives, as well as the different types of studies in which these models can be used. In view of all that, we propose a decision algorithm to create an animal model of repaired tetralogy of Fallot. This synthesis should furthermore help in the development of future studies and in the design of new experimental models, thus allowing greater insight into this disease, while not forgetting the ultimate goal of broadening future therapeutic measures to reduce the morbidity and mortality of this prevalent congenital heart disease.

Right Ventricular Function After Pulmonary Artery Banding: Adaptive Processes Assessed by CMR and Conductance Catheter Measurements in Sheep

This experimental study describes the adaptive processes of the right ventricular (RV) myocardium after pulmonary artery banding (PAB) evaluated by cine cardiac magnetic resonance (CMR), phase-contrast CMR (PC-CMR), and conductance catheter. Seven sheep were subjected to CMR 3 months after PAB. Conductance catheter measurements were performed before and 3 months after PAB. Four nonoperated, healthy, age-matched animals served as controls. Higher RV masses (p < 0.01), elevated RV end-systolic volumes (p < 0.05), and lower RV ejection fraction (p < 0.01) were observed in the operated group. The time-to-peak pulmonary artery flow was longer in the banding group (p < 0.01). RV maximal pressure and RV end-diastolic pressure correlated with the time-to-peak flow in the pulmonary artery (r = - 0.70 and - 0.69, respectively). In summary, PAB caused RV hypertrophy, increased myocardial contractility, and decreased RV-EF and cardiac output. The time-to-peak pulmonary artery flow correlated with RV pressures.

Assessment of Right Atrium Function in Patients With Systemic Lupus Erythematosus With Different Pulmonary Artery Systolic Pressures by 2-Dimensional Speckle-Tracking Echocardiography

OBJECTIVES

To assess right atrium (RA) function of patients with systemic lupus erythematosus (SLE) and pulmonary artery hypertension (PAH) by 2-dimensional speckle-tracking echocardiography.

METHODS

Thirty matched healthy adults were selected as group A. Then, 102 patients with SLE were divided into 3 groups according to the severity of PAH. Group B included 37 patients without PAH (pulmonary artery [PA] systolic pressure ≤ 30 mm Hg); group C included 34 patients with PAH (PA systolic pressure of 30-50 mm Hg); and group D included 31 patients with PAH (PA systolic pressure ≥ 50 mm Hg). Parameters evaluated included RA maximum volume, minimum volume, preatrial contraction volume, passive ejection fraction (EF), and active EF. The global peak longitudinal systolic strain rate and early and late diastolic strain rates of the RA were obtained by 2-dimensional speckle-tracking echocardiography.

RESULTS

No significant differences were found in all parameters between groups B and A (P > .05). The RA maximum volume, minimum volume, preatrial contraction volume, active EF, and late diastolic strain rate in groups C and D were significantly increased compared with those in groups A and B, and the parameters in group D were significantly higher than those in group C (P < .05). Although the RA passive EF, early diastolic strain rate, and systolic strain rate in groups C and D were significantly decreased compared with those in groups A and B, those in group D were significantly lower than those in group C (P < .05).

CONCLUSIONS

Two-dimensional speckle-tracking echocardiography could effectively assess RA function in patients with SLE who have different severities of PAH.

Echocardiographic Evaluation of the Right Atrial Area Index in Dogs with Pulmonary Hypertension

Background

Right atrial area (RAA) is a prognostic factor in human patients with pulmonary arterial hypertension (PAH). Reference intervals for RAA have been described in healthy dogs.

Objectives

To evaluate RAA indexed to the body surface area in dogs with PAH as an indicator of right atrial size, PAH severity and right‐sided congestive heart failure (R‐CHF).

Animals

A total of 119 client‐owned dogs, 48 dogs with PAH and 71 control dogs.

Methods

Prospective observational study. Pulmonary arterial hypertension was classified according to the tricuspid regurgitation pressure gradient (TRPG) as mild (36–50 mmHg), moderate (51–75 mmHg), or severe (>75 mmHg). The RAA index was calculated as the RAA divided by body surface area.

Results

The RAA index was higher in dogs with moderate PAH (13.3 cm²/m²; range, 3.4–24.7 cm²/m²) and severe PAH (12.1 cm²/m²; range, 5.4–21.8 cm²/m²) than in those with mild PAH (6.7 cm²/m²; range, 4.8–10.7 cm²/m²) or in controls (7.3 cm²/m²; range, 4.2–10.2 cm²/m²; P < 0.001). The RAA index was higher (P < 0.0001) in dogs with R‐CHF (17.5 cm²/m²; range, 12.7–24.7 cm²/m²) compared to those without R‐CHF (7.6 cm²/m²; range, 4.4–19.4 cm²/m²). The most accurate cutoff value of the RAA index to identify R‐CHF was >12.3 cm²/m² (sensitivity, 100%; specificity, 89.5%). In dogs with PAH, severity of tricuspid regurgitation (TR) was the only independent predictor of RAA index based on multivariate analysis (P < 0.02).

Conclusions and Clinical Importance

The RAA index can be used to evaluate right atrial size in dogs and may be more effective than TRPG in predicting R‐CHF in dogs with PAH. The severity of TR is the main determinant of the RAA index in dogs with PAH.

Echocardiographic evaluation of the right ventricular dimension and systolic function in dogs with pulmonary hypertension

Background

Right ventricular (RV) enlargement and dysfunction are associated with prognosis in humans with pulmonary hypertension (PH).

Hypothesis/Objectives

To assess RV size and systolic function in dogs with PH and to determine if they are associated with disease severity and right‐sided congestive heart failure (R‐CHF).

Animals

89 dogs with PH and 74 healthy dogs.

Methods

Prospective observational study. PH was classified according to the tricuspid regurgitation pressure gradient. RV end‐diastolic area (RVEDA) index was calculated as RVEDA divided by body surface area. RV systolic function was assessed with the tricuspid annular plane systolic excursion (TAPSE) and the RV fractional area change (FAC) normalized for body weight (TAPSEn and FACn, respectively).

Results

RVEDA index was higher in dogs with moderate PH (10.8 cm²/m²; range, 6.2‐14.4 cm²/m²) and severe PH (12.4 cm²/m²; range, 7.7‐21.4 cm²/m²) than in those with mild PH (8.4 cm²/m²; range, 4.8‐11.6 cm²/m²) and control dogs (8.5 cm²/m²; range, 2.8‐11.6 cm²/m²; P < .001). RVEDA index was significantly higher in dogs with R‐CHF (13.7 cm²/m²; range, 11.0‐21.4 cm²/m²) than in dogs without R‐CHF (9.4 cm²/m²; range, 4.8‐17.1 cm²/m²; P < .001). The severity of tricuspid regurgitation (TR) was the only independent predictor of the RVEDA index (P < .001). TAPSEn and FACn were not significantly different among varying degrees of PH severity and between dogs with and without R‐CHF.

Conclusions and Clinical Importance

The RVEDA index can be used to evaluate RV size in dogs. It can provide additional information in dogs with PH and predict R‐CHF. Severity of TR is the main determinant of RV enlargement in dogs with PH.

Biatrial performance in children with hypertrophic cardiomyopathy: CMR study

OBJECTIVES

To investigate biatrial mechanics and their relation with left ventricular outflow tract (LVOT) obstruction (LVOTO), the degree of hypertrophy, indices of ventricular diastolic function and fibrosis in children with hypertrophic cardiomyopathy (HCM).

METHODS

Fifty-five consecutive, prospectively recruited children with HCM (mean age 12.5 ± 4.6 years, 69.1% male), 19 (34.5%) of whom had LVOTO, underwent cardiac magnetic resonance and echocardiography with quantification of phasic components of biatrial function, biventricular diastolic function and fibrosis. Twenty healthy, sex-matched subjects served as controls.

RESULTS

We found a significant increase of left atrial (LA) and right atrial (RA) volumes and reduction in the majority of indices of contractile function, strains and strain rates (p < 0.05) in children with HCM compared with controls. Nearly all of the LA dynamics markers attained a significant association with the LVOT gradient (p < 0.05), the RA volumes and contractile functions were affected by LV fibrosis and mass (p < 0.05), and the RA mechanical components were related to the degree of LVOTO (p < 0.05). The minority of biatrial dynamics markers were associated with indices of ventricular diastolic function.

CONCLUSIONS

The majority of biatrial volumetric and functional indices were severely compromised in children with HCM compared with controls. The degree of LVOTO appears to trigger LA volumetric and LA and RA mechanical malfunction. On the other hand, the deterioration of RA volumetric components was linked to LV fibrosis and mass.

KEY POINTS

• Biatrial function was severely compromised in children with HCM. • Left atrial malfunction was associated with the degree of LVOTO. • Fibrosis and LV mass were related to RA volumetric and contractile dysfunction. • The degree of LVOTO was linked to right atrial mechanical abnormalities.

Right Ventricular Fiber Structure as a Compensatory Mechanism in Pressure Overload: A Computational Study

Right ventricular failure (RVF) is a lethal condition in diverse pathologies. Pressure overload is the most common etiology of RVF, but our understanding of the tissue structure remodeling and other biomechanical factors involved in RVF is limited. Some remodeling patterns are interpreted as compensatory mechanisms including myocyte hypertrophy, extracellular fibrosis, and changes in fiber orientation. However, the specific implications of these changes, especially in relation to clinically observable measurements, are difficult to investigate experimentally. In this computational study, we hypothesized that, with other variables constant, fiber orientation alteration provides a quantifiable and distinct compensatory mechanism during RV pressure overload (RVPO). Numerical models were constructed using a rabbit model of chronic pressure overload RVF based on intraventricular pressure measurements, CINE magnetic resonance imaging (MRI), and diffusion tensor MRI (DT-MRI). Biventricular simulations were conducted under normotensive and hypertensive boundary conditions using variations in RV wall thickness, tissue stiffness, and fiber orientation to investigate their effect on RV pump function. Our results show that a longitudinally aligned myocardial fiber orientation contributed to an increase in RV ejection fraction (RVEF). This effect was more pronounced in response to pressure overload. Likewise, models with longitudinally aligned fiber orientation required a lesser contractility for maintaining a target RVEF against elevated pressures. In addition to increased wall thickness and material stiffness (diastolic compensation), systolic mechanisms in the forms of myocardial fiber realignment and changes in contractility are likely involved in the overall compensatory responses to pressure overload.

Right atrial mechanics provide useful insight in pediatric pulmonary hypertension

Right atrial (RA) mechanics have been studied infrequently in children in the past due to technical constraints. With the advent of strain imaging, RA physiology can now be studied in greater detail. The principal aim of this study was to describe functional changes in right heart mechanics of children with idiopathic pulmonary arterial hypertension (PAH), by using new applications of RA strain. In this retrospective study, we evaluated RA mechanics of 20 patients (age range = 3-23 years) with PAH and 18 control patients. RA longitudinal strain (RALS) and longitudinal displacement (LD) were calculated by speckle-tracking echocardiography. RALS was plotted against LD, producing a characteristic strain-displacement (S-D) loop. Standard indices of right heart function and right heart catheterization data were obtained. Patients were clinically subdivided into "compensated" and "decompensated" PAH. A chart review was performed to identify patients who subsequently developed adverse outcomes, including death, awaiting or received lung and/or heart transplantation. RALS was significantly lower in decompensated PAH compared with both controls and compensated PAH. Area enclosed by S-D loops differed significantly between the compensated and decompensated PAH subgroups (5.33 [3.90-9.44] versus 1.83 [1.17-2.36], P < 0.05). S-D loop area and RALS possessed high sensitivity and specificity compared to other parameters for identifying children with PAH who subsequently developed adverse outcomes. In particular, their sensitivities and specificities were greatly superior compared to those of tricuspid annular plane systolic excursion (TAPSE). RALS may represent a useful metric for assessing right ventricular (RV) dysfunction. S-D loops, composed over an entire cardiac cycle, may present useful, composite information regarding both systolic and diastolic right heart function. RA mechanics may serve as useful tools for identifying patients with more severe PAH, who are at risk for future adverse outcomes associated with RV failure.

Maintained right ventricular pressure overload induces ventricular-arterial decoupling in mice

NEW FINDINGS

What is the central question of this study? The aim was to investigate whether complementary assessment of non-invasive ultrasound imaging together with closed chest-derived intracardiac pressure-volume catheterization is applicable to mice for an in-depth characterization of right ventricular (RV) function even upon maintained pressure overload. What is the main finding and its importance? Characterization of RV function by the complementary use of echocardiographic imaging together with pressure-volume catheterization reveals ventricular-arterial decoupling upon maintained pressure overload, where RV systolic function correlates with ventricular-arterial coupling rather than contractility, whereas diastolic function correlates well with RV diastolic pressure. This combined approach allows us to phenotype RV function and dysfunction better in genetically modified and/or pharmacologically treated mice. Assessment of right ventricular (RV) function in rodents is a challenge because of the complex RV anatomy and structure. To date, the best characterization of RV function has been achieved by accurate cardiovascular phenotyping, involving a combination of non-invasive imaging and intracardiac pressure-volume measurements. We sought to investigate the feasibility of two complementary phenotyping techniques for the evaluation of RV function in an experimental mouse model of sustained RV pressure overload. Mice underwent either sham surgery (n = 5) or pulmonary artery banding (n = 8) to induce isolated RV pressure overload. After 3 weeks, indices of RV function were assessed by echocardiography (Vevo2100) and closed chest-derived invasive pressure-volume measurements (PVR-1030). Pulmonary artery banding resulted in RV hypertrophy and dilatation accompanied by systolic and diastolic dysfunction. Invasive RV haemodynamic measurements demonstrated an increased end-systolic elastance and arterial elastance after pulmonary artery banding compared with sham operation, resulting in ventricular-arterial decoupling. Regression analysis revealed that tricuspid annular plane systolic excursion is correlated with ventricular-arterial coupling (r² = 0.77, P = 0.002) rather than with RV contractility (r² = -0.61, P = 0.07). Furthermore, the isovolumic relaxation time to ECG-derived R-R interval and the ratio of the early diastolic peak velocity measured by pulsed wave Doppler to the early diastolic peak obtained during tissue Doppler imaging correlate well with RV end-diastolic pressure (r² = 0.87, P = 0.0001 and r² = 0.82, P = 0.0009, respectively). Commonly used indices of systolic RV function are associated with RV-arterial coupling rather than contractility, whereas diastolic indices well correlate with end-diastolic pressure when there is maintained pressure overload.

Right Atrial Deformation in Predicting Outcomes in Pediatric Pulmonary Hypertension

BACKGROUND

Elevated right atrial (RA) pressure is a risk factor for mortality, and RA size is prognostic of adverse outcomes in pulmonary hypertension (PH). There is limited data on phasic RA function (reservoir, conduit, and pump) in pediatric PH. We sought to evaluate (1) the RA function in pediatric PH patients compared with controls, (2) compare the RA deformation indices with Doppler indices of diastolic dysfunction, functional capacity, biomarkers, invasive hemodynamics, and right ventricular functional indices, and (3) evaluate the potential of RA deformation indices to predict clinical outcomes.

METHODS AND RESULTS

Sixty-six PH patients (mean age 7.9±4.7 years) were compared with 36 controls (7.7±4.4 years). RA and right ventricular deformation indices were obtained using 2-dimensional speckle tracking (2DCPA; TomTec, Germany). RA strain, strain rates, emptying fraction, and right ventricular longitudinal strain were measured. RA function was impaired in PH patients versus controls (P<0.001). There were significant associations between RA function with invasive hemodynamics (P<0.01). RA reservoir, pump function, the rate of RA filling, and atrial minimum volume predicted adverse clinical outcomes (hazard ratio [HR], 0.15; confidence interval [CI], 0.03-0.73; P<0.01; HR, 0.05; CI, 0.003-0.43; P<0.004; HR, 0.04; CI, 0.006-0.56; P<0.01; and HR, 8.6; CI, 1.6-37.2; P<0.01, respectively).

CONCLUSIONS

RA deformation properties are significantly altered in pediatric PH patients. Progressive worsening of RA reservoir and conduit functions is related to changes in right ventricular diastolic dysfunction. RA reservoir function, pump function, the rate of atrial filling, and atrial minimum volume emerged as outcome predictors in pediatric PH.

Non-invasive imaging of global and regional cardiac function in pulmonary hypertension

Pulmonary hypertension (PH) is a progressive illness characterized by elevated pulmonary artery pressure; however, the main cause of mortality in PH patients is right ventricular (RV) failure. Historically, improving the hemodynamics of pulmonary circulation was the focus of treatment; however, it is now evident that cardiac response to a given level of pulmonary hemodynamic overload is variable but plays an important role in the subsequent prognosis. Non-invasive tests of RV function to determine prognosis and response to treatment in patients with PH is essential. Although the right ventricle is the focus of attention, it is clear that cardiac interaction can cause left ventricular dysfunction, thus biventricular assessment is paramount. There is also focus on the atrial chambers in their contribution to cardiac function in PH. Furthermore, there is evidence of regional dysfunction of the two ventricles in PH, so it would be useful to understand both global and regional components of dysfunction. In order to understand global and regional cardiac function in PH, the most obvious non-invasive imaging techniques are echocardiography and cardiac magnetic resonance imaging (CMRI). Both techniques have their advantages and disadvantages. Echocardiography is widely available, relatively inexpensive, provides information regarding RV function, and can be used to estimate RV pressures. CMRI, although expensive and less accessible, is the gold standard of biventricular functional measurements. The advent of 3D echocardiography and techniques including strain analysis and stress echocardiography have improved the usefulness of echocardiography while new CMRI technology allows the measurement of strain and measuring cardiac function during stress including exercise. In this review, we have analyzed the advantages and disadvantages of the two techniques and discuss pre-existing and novel forms of analysis where echocardiography and CMRI can be used to examine atrial, ventricular, and interventricular function in patients with PH at rest and under stress.