Assessment of right ventricular systolic function in heart transplant patients: Correlation between echocardiography and cardiac magnetic resonance imaging. Investigation of the accuracy and reliability of echocardiography

Multiparametric assessment of right ventricular function in heart transplant recipients by echocardiography and relations with pulmonary hemodynamics

OBJECTIVE

Right ventricular (RV) dilatation and dysfunction are usually present in heart transplant (HTx) patients and worsened with residual pulmonary hypertension (PH). We aimed to determine the ability of different echocardiographic modalities to evaluate RV function in comparison with cardiac magnetic resonance (CMR) and their relations with pulmonary hemodynamics in HTx patients.

METHODS

A total of 62 data sets [echocardiographic, hemodynamic, and CMR] were acquired from 35 HTx patients. Comprehensive echocardiography, including two-dimensional (2D) transthoracic echocardiography, speckle tracking echocardiography, and three-dimensional (3D) echocardiography, was performed. Mean pulmonary artery pressure (mPAP) was obtained invasively from right heart catheterization. The correlations between all echocardiographic parameters and CMR imaging data and the differences between patients with and without residual PH were evaluated.

RESULTS

Diastolic and systolic RV volumes and RV ejection fraction (RVEF) by 3D echocardiography correlated strongly with CMR-derived volumes and RVEF (r = .91, r = .79, r = .64; p < .0001 for each, respectively). Among other parameters, RV fractional area change (r = .439; p < .001) and RV free wall longitudinal strain (RVFW-LS) (r = -.34; p < .05) correlated moderately with CMR-RVEF, whereas tricuspid annulus S' velocity (r = .29; p < .05) and tricuspid annular systolic plane excursion (r = .27; p < .05) correlated weakly with CMR-RVEF. Additionally, 3D-RVEF and RVFW-LS were significantly decreased in studies with mPAP ≥ 20 mm Hg in comparison to those with mPAP < 20 mm Hg (47.7 ± 3.7 vs. 50.9 ± 5.3, p = .04 and -15.5 ± 3.1 vs. -17.5 ± 3, p = .03, respectively).

CONCLUSION

The best method for the evaluation of RV function in HTx recipients is 3D echocardiography. Besides, the subclinical impact of residual PH on RV function can be best determined by RVFW-LS and 3D-RVEF in these patients.

Echocardiographic assessment of radial right ventricular function in heart transplant recipients

Aims

Right ventricular (RV) allograft dysfunction is present in half of all heart transplant (HT) recipients. Non‐invasive assessment of RV function in the setting of rejection is not well described. We outline an echocardiographic technique, short‐axis fractional area change (SAXFAC), to evaluate RV function in the HT population and correlate this with the grade of pathologic rejection.

Methods and results

We retrospectively reviewed the electronic medical records of 110 people who received a HT between 1 January 2015 and 29 February 2020 and had no evidence of rejection. One hundred eighty‐two transthoracic echocardiograms (TTEs) completed up to 1 year from the date of transplantation were analysed for the target acoustic window, the parasternal mid‐ventricular short‐axis view. Sixty‐one TTEs from 23 healthy transplants were deemed appropriate for SAXFAC determination. Thirty‐three organ recipients with at least grade 1R allograft rejection were also identified, and their TTEs screened for SAXFAC analysis. Two expert readers independently calculated SAXFAC as follows: RV end‐diastolic area minus end‐systolic area divided by end‐diastolic area. Using commercially available software (Epsilon, Ann Arbor, Michigan), we quantified RV radial strain, longitudinal strain, and apical fractional area change (FAC). Twenty‐eight transplant recipients with grade 0R or 1R rejection and nine patients with clinically significant rejection completed the study analysis. SAXFAC demonstrated significant variability in the entire population with an inverse relationship to severity of allograft rejection (P ≤ 0.01). Radial strain and FAC were also associated with clinically significant rejection (P ≤ 0.01).

Conclusions

Short‐axis fractional area change is a simple two‐dimensional technique to assess RV function in HT recipients and showed no significant inter‐observer variability. In our small, single‐centre, retrospective case series, lower SAXFAC values were associated with clinically significant allograft rejection. The small sample size and infrequent occurrence of rejection make our observations hypothesis‐generating only. We advocate dedicated RV SAXFAC imaging planes be included when assessing allograft function.

Echocardiographic Assessment of Right Ventricular-Arterial Coupling in Predicting Prognosis of Pulmonary Arterial Hypertension Patients

In response to an increased afterload in pulmonary arterial hypertension (PAH), the right ventricle (RV) adapts by remodeling and increasing contractility. The idea of coupling refers to maintaining a relatively constant relationship between ventricular contractility and afterload. Twenty-eight stable PAH patients (mean age 49.5 ± 15.5 years) were enrolled into the study. The follow-up time of this study was 58 months, and the combined endpoint (CEP) was defined as death or clinical deterioration. We used echo TAPSE as a surrogate of RV contractility and estimated systolic pulmonary artery pressure (sPAP) reflecting RV afterload. Ventricular–arterial coupling was evaluated by the ratio between these two parameters (TAPSE/sPAP). In the PAH group, the mean pulmonary artery pressure (mPAP) was 47.29 ± 15.3 mmHg. The mean echo-estimated TAPSE/sPAP was 0.34 ± 0.19 mm/mmHg and was comparable in value and prognostic usefulness to the parameter derived from magnetic resonance and catheterization (ROC analysis). Patients who had CEP (n = 21) had a significantly higher mPAP (53.11 ± 17.11 mmHg vs. 34.86 ± 8.49 mmHg, p = 0.03) and lower TAPSE/sPAP (0.30 ± 0.21 vs. 0.43 ± 0.23, p = 0.04). Patients with a TAPSE/sPAP lower than 0.25 mm/mmHg had worse prognosis, with log-rank test p = 0.001. the echocardiographic estimation of TAPSE/sPAP offers an easy, reliable, non-invasive prognostic parameter for the comprehensive assessment of hemodynamic adaptation in PAH patients.

Donor-recipient predicted heart mass ratio and right ventricular-pulmonary arterial coupling in heart transplant

OBJECTIVES

Right ventricular-pulmonary arterial (RV-PA) coupling interactions are largely unexplored in heart transplant patients. The outcome of this study was RV-PA coupling at 7 and 30 days after heart transplant and its association with donor-recipient size matching.

METHODS

Clinical, echocardiographic and haemodynamic data from a retrospective cohort of heart transplant recipients and respective donors were reviewed. Coupling between RV-PA was examined by assessing the RV fractional area change and pulmonary artery systolic pressure ratio. Donor-recipient size matching was assessed by the predicted heart mass (PHM) ratio, and groups with a PHM ratio <1 and ≥1 were compared.

RESULTS

Forty-four heart transplant recipients were included in this study (50 years, 57% male sex). Postoperative RV-PA coupling improved from 7 to 30 days (RV fractional area change/pulmonary artery systolic pressure 0.9 ± 0.3 vs 1.2 ± 0.3; P < 0.001). A positive association was found between an adequate PHM ratio and improvement of RV fractional area change/pulmonary artery systolic pressure at 30 days, independent of graft ischaemic time and pre-existent pulmonary hypertension (B coefficient 0.54; 95% confidence interval 0.11-0.97; P = 0.016; adjusted R2 = 0.24).

CONCLUSIONS

These findings highlight the role of PHM as a metric to help donor selection and suggest its impact in RV-PA coupling interactions post-heart transplant.

Prognostic value of right ventricular free wall longitudinal strain in a large cohort of outpatients with left-side heart disease

AIMS

Right ventricular free wall longitudinal strain (RVFWLS) has been proposed as an accurate and sensitive measure of right ventricular function that could integrate other conventional parameters such as tricuspid annulus plane systolic excursion (TAPSE) and fractional area change (FAC%). The aim of the present study was to evaluate the relationship between RVFWLS and outcomes in stable asymptomatic outpatients with left-sided structural heart disease.

METHODS AND RESULTS

We enrolled 458 asymptomatic patients with left-side heart diseases and any ejection fraction who were referred for echocardiography to two Italian centres. The composite endpoint of death for any cause and heart failure hospitalization was used as primary outcome of this analysis. After a mean follow-up of 5.4 ± 1.2 years, 145 patients (31%) reached the combined endpoint. Most of echocardiographic parameters were related to outcomes, including right ventricular functional parameters. Mean value of RVFWLS in our cohort was -21 ± 8% and it was significantly related to the combined endpoint and in multivariable Cox-regression model; when tested with other echocardiographic parameters that were significantly related to outcome at univariate analysis, RVFWLS maintained its independent association with outcome (hazard ratio 0.963, 95% confidence interval 0.948-0.978; P = 0.0001). The best cut-off value of RVFWLS to predict outcome was -22% (area under the curve 0.677; P < 0.001; sensitivity 70%; 65% specificity).

CONCLUSION

RVFWLS may help clinicians to identify patients with left-sided structural heart disease at higher risk for first heart failure hospitalization and death for any cause.

A comparison of artificial intelligence-based algorithms for the identification of patients with depressed right ventricular function from 2-dimentional echocardiography parameters and clinical features

Background

Recognizing low right ventricular (RV) function from 2-dimentiontial echocardiography (2D-ECHO) is challenging when parameters are contradictory. We aim to develop a model to predict low RV function integrating the various 2D-ECHO parameters in reference to cardiac magnetic resonance (CMR)-the gold standard.

Methods

We retrospectively identified patients who underwent a 2D-ECHO and a CMR within 3 months of each other at our institution (American University of Beirut Medical Center). We extracted three parameters (TAPSE, S' and FAC_RV) that are classically used to assess RV function. We have assessed the ability of 2D-ECHO derived parameters and clinical features to predict RV function measured by the gold standard CMR. We compared outcomes from four machine learning algorithms, widely used in the biomedical community to solve classification problems.

Results

One hundred fifty-five patients were identified and included in our study. Average age was 43±17.1 years old and 52/156 (33.3%) were females. According to CMR, 21 patients were identified to have RV dysfunction, with an RVEF of 34.7%±6.4%, as opposed to 54.7%±6.7% in the normal RV population (P<0.0001). The Random Forest model was able to detect low RV function with an AUC =0.80, while general linear regression performed poorly in our population with an AUC of 0.62.

Conclusions

In this study, we trained and validated an ML-based algorithm that could detect low RV function from clinical and 2D-ECHO parameters. The algorithm has two advantages: first, it performed better than general linear regression, and second, it integrated the various 2D-ECHO parameters.

Impact of right ventricular systolic function after heart transplantation on exercise capacity

BACKGROUND

Right ventricular (RV) systolic parameters are difficult to assess in heart transplant recipients (HTRs) compared to healthy people because of discordant data, and their impact on exercise capacity remains undefined. We sought to retrospectively assess the impact of RV systolic function on exercise capacity after heart transplantation.

METHODS

We analyzed data from 61 HTRs who underwent transthoracic echocardiography (TTE), cardiac magnetic resonance imaging (CMR), and exercise capacity assessment by 6-minute walking test (6MWT) and cardiopulmonary exercise testing (CPET) at 1- and 2-year follow-ups.

RESULTS

Transthoracic echocardiography RV longitudinal systolic function including tricuspid annular plan systolic excursion (TAPSE), peak systolic S' wave tricuspid annular velocity (PSVtdi) and RV free wall longitudinal strain was decreased at 1 year (respectively, 15 ± 3 mm, 10 ± 3 cm/s, and -19 ± 5%) and at 2 years (respectively, 15 ± 3 mm, 10 ± 2 cm/s, and -20 ± 5%) with no significant difference between both evaluations; meanwhile, RV ejection fraction (RVEF) measured by CMR was preserved. Mean percentage of predicted peak oxygen consumption was altered, but improved between the first and second year (55 ± 18 vs 60 ± 18%, P = .038). PSVtdi was weakly correlated with 6MWT distance (r = .426, P = .017) and RVEF with the predicted distance at 6MWT (r = .410, P = .027) at the 1-year follow-up.

CONCLUSIONS

Despite decreasing values, RV longitudinal systolic function has a weak impact on exercise capacity of HTRs. PSVtdi and RVEF are the most pertinent parameters to assess the impact of RV systolic function on exercise capacity after heart transplantation. These results should lead to redefine normal RV systolic function thresholds for HTRs.

Fetal Dilated Cardiomyopathy Associated With Variants of Uncertain Significance in MYH7 and DSG2 Genes: A Case Report and Review of the Literature

BACKGROUND

Fetal dilated cardiomyopathy (DCM) is an uncommon prenatal diagnosis associated with significant morbidity and mortality.

CASE

This report describes a patient with a diagnosis of fetal DCM at 31⁰ weeks gestation, several weeks after a maternal flu-like illness. Spontaneous improvement was noted on serial echocardiograms. Maternal Coxsackievirus B titers were significantly elevated at 1:80, although post-natal cord blood test results were negative. Genetic panel testing for DCM demonstrated two heterozygous variants of uncertain significance in the MYH7 and DSG2 genes. Although an early post-natal echocardiogram demonstrated a normal left ventricular ejection fraction, right ventricular dysfunction was noted with subsequent cardiac decompensation requiring temporary inotropic support. An echocardiogram at the age of 2 years confirmed normal biventricular function.

CONCLUSION

The finding of fetal DCM should trigger a broad evaluation. In the setting of limited fetal cardiac reserve, the significant hemodynamic changes that occur post-natally may trigger additional decompensation. Clinicians should be aware of the prognostic value of right ventricular function, as measured by fractional area change, in addition to the limitations of serologic and genetic testing.

Multi-modal imaging of the pediatric heart transplant recipient

The assessment of pediatric patients after orthotropic heart transplantation (OHT) relies heavily on non-invasive imaging. Because of the potential risks associated with cardiac catheterization, expanding the role of non-invasive imaging is appealing. Echocardiography is fast, widely available, and can provide an accurate assessment of chamber sizes and function. Advanced echocardiographic methods, such as myocardial deformation, have potential to assess for acute rejection or cardiac allograft vasculopathy (CAV). While not currently part of routine care, cardiac magnetic resonance imaging (CMR) and computed tomography may potentially aid in the detection of graft complications following OHT. In particular, CMR tissue characterization holds promise for diagnosing rejection, while quantitative perfusion and myocardial late gadolinium enhancement may have a role in the detection of CAV. This review will evaluate standard and novel methods for non-invasive assessment of pediatric patients after OHT.

Comparison of echocardiographic indices of right ventricular systolic function and ejection fraction obtained with continuous thermodilution in critically ill patients

Background

Though echocardiographic evaluation assesses the right ventricular systolic function, which of the existing parameters best reflects the right ventricular ejection fraction (RVEF) in the critically ill patients is still uncertain. We aimed to determine the relationship between echocardiographic indices of right ventricular systolic function and RVEF.

Methods

Prospective observational study was conducted in a mixed Surgical Intensive Care Unit (Hôpital Lariboisière, Paris, France) from November 2017 to November 2018. All critically ill patients monitored with a pulmonary artery catheter were assessed. We collected echocardiographic indices of right ventricular function (tricuspid annular plane systolic excursion, TAPSE; peak systolic velocity of pulsed tissue Doppler at lateral tricuspid annulus, S′; fractional area change, FAC; right ventricular index of myocardial performance, RIMP; isovolumic acceleration, IVA; end-diastolic diameter ratio, EDDr) and compared them with the RVEF obtained from continuous volumetric pulmonary artery catheter.

Results

Twenty-five patients were analyzed. Admission diagnosis was acute heart failure in 11 patients and septic shock in 14 patients. Median age was 70 years [57–80], norepinephrine median dose was 0.29 μg/kg/min [0.14–0.50], median Sequential Organ Failure Assessment score was 12 [10–14], and mortality at day 28 was 56%. When compared to RVEF, TAPSE had the highest correlation coefficient (rho = 0.78, 95% CI 0.52 to 0.89, p < 0.001). S′ was also correlated to RVEF (rho = 0.64, 95% CI 0.60 to 0.80, p = 0.001) whereas FAC, RIMP, IVA, and EDDr did not. TAPSE lower than 16 mm, S′ lower than 11 cm/s, and EDDr higher than 1 were always associated with a reduced RVEF.

Conclusions

We found that amongst indices of right ventricular systolic function, TAPSE and S′ were well correlated with thermodilution-derived RVEF in critically ill patients.

Electronic supplementary material

The online version of this article (10.1186/s13054-019-2582-7) contains supplementary material, which is available to authorized users.

Tricuspid regurgitation and the right ventricle in risk stratification and timing of intervention

Tricuspid regurgitation natural history and treatment remains poorly understood. Right ventricular function is a key factor in determining prognosis, timing for intervention and longer-term outcome. The right ventricle is a thin walled chamber with a predominance of longitudinal fibres and a shared ventricular septum. In health, the low-pressure pulmonary circulation results in a highly compliant RV well equipped to respond to changes in preload but sensitive to even small alterations in afterload. In Part 1 of this article, discussion focuses on key principles of ventricular function assessment and the importance of right ventricular chamber size, volumes and ejection fraction, particularly in risk stratification in tricuspid regurgitation. Part 2 of this article provides an understanding of the causes of tricuspid regurgitation in the contemporary era, with emphasis on key patient groups and their management.