Doppler tissue imaging in children following cardiac transplantation: a comparison to catheter derived hemodynamics

Echocardiography to predict left ventricular filling pressure for long-term paediatric heart transplant patients

OBJECTIVES

Left ventricular diastolic dysfunction is a recognised sequela following transplantation in paediatric heart transplant patients. Traditional echocardiographic indices do not correlate well with left ventricular filling pressure immediately after transplantation. This study aimed to assess whether these indices have any long-term correlation after transplantation in paediatric patients.

METHODS

A retrospective chart review of 41 patients who had a heart transplant before the age of 24 years was performed. The median time since the transplantation was 11 years. Data obtained from surveillance cardiac catheterisation and echocardiographic examination were reviewed. Traditional echocardiographic indices of diastolic function were compared with the pulmonary capillary wedge pressure and left ventricular end-diastolic pressure obtained from cardiac catheterisation.

RESULTS

The median age at transplant was 12.1 years, and the median time since transplant was 11 years. Eighteen patients (43%) had a history of at least one rejection episode and 12 patients (29%) had a history of cardiac allograft vasculopathy. There was no correlation between mitral inflow E velocity, mitral E/A ratio, tissue Doppler velocities, mitral E/e' (mitral inflow E velocity to mitral annular velocity), and elevated pulmonary capillary wedge pressure or elevated left ventricular end-diastolic pressure. There was no correlation between mitral valve deceleration time or isovolumetric relaxation time with elevated pulmonary capillary wedge pressure or elevated left ventricular end-diastolic pressure.

CONCLUSION

Our findings suggest that traditional echocardiographic indices of diastolic function do not correlate well with elevated invasive pulmonary capillary wedge pressure or elevated left ventricular end-diastolic pressure in paediatric heart transplant patients' long-term post-transplantation.

Multimodality Imaging to Detect Rejection, and Cardiac Allograft Vasculopathy in Pediatric Heart Transplant Recipients—An Illustrative Review

The three most common modalities of graft surveillance in pediatric heart transplant (HT) recipients include echocardiography, coronary angiography, and endomyocardial biopsy (EMB). The survival outcomes after HT in children have improved considerably in recent years. However, allograft rejection and cardiac allograft vasculopathy remain the leading cause of death or re-transplantation. The routine surveillance by EMB and coronary angiography are invasive and risky. Newer noninvasive echocardiographic techniques, including tissue Doppler imaging (TDI), 2-D speckle tracking echocardiography, CT coronary angiography (CTCA), cardiovascular magnetic resonance (CMR), single-photon emission computed tomography (SPECT), and positron emission tomography (PET) and invasive techniques such as intravascular ultrasound (IVUS), functional flow reserve (CFR) of coronary arteries, optical coherence tomography (OCT), have emerged as powerful tools which may help early recognition of sub-clinical rejection, response to treatment, early detection, and progression of CAV. The multimodality imaging approach, including noninvasive and invasive tests, is the future for the transplanted heart to detect dysfunction, rejections, and early CAV. This review illustrates noninvasive and invasive imaging techniques currently used or could be considered for clinical use in detecting heart transplant rejection, dysfunction, and CAV in children.

Echocardiographic RV-E/e' for predicting right atrial pressure: a review

Right atrial pressure (RAP) is a key cardiac parameter of diagnostic and prognostic significance, yet current two-dimensional echocardiographic methods are inadequate for the accurate estimation of this haemodynamic marker. Right-heart trans-tricuspid Doppler and tissue Doppler echocardiographic techniques can be combined to calculate the right ventricular (RV) E/e′ ratio – a reflection of RV filling pressure which is a surrogate of RAP. A systematic search was undertaken which found seventeen articles that compared invasively measured RAP with RV-E/e′ estimated RAP. Results commonly concerned pulmonary hypertension or advanced heart failure/transplantation populations. Reported receiver operating characteristic analyses showed reasonable diagnostic ability of RV-E/e′ for estimating RAP in patients with coronary artery disease and RV systolic dysfunction. The diagnostic ability of RV-E/e′ was generally poor in studies of paediatrics, heart failure and mitral stenosis, whilst results were equivocal in other diseases. Bland–Altman analyses showed good accuracy but poor precision of RV-E/e′ for estimating RAP, but were limited by only being reported in seven out of seventeen articles. This suggests that RV-E/e′ may be useful at a population level but not at an individual level for clinical decision making. Very little evidence was found about how atrial fibrillation may affect the estimation of RAP from RV-E/e′, nor about the independent prognostic ability of RV-E/e′ . Recommended areas for future research concerning RV-E/e′ include; non-sinus rhythm, valvular heart disease, short and long term prognostic ability, and validation over a wide range of RAP.

Echocardiographic RV-E/e′ for predicting right atrial pressure: a review

Right atrial pressure (RAP) is a key cardiac parameter of diagnostic and prognostic significance, yet current two-dimensional echocardiographic methods are inadequate for the accurate estimation of this haemodynamic marker. Right-heart trans-tricuspid Doppler and tissue Doppler echocardiographic techniques can be combined to calculate the right ventricular (RV) E/e′ ratio–a reflection of RV filling pressure which is a surrogate of RAP. A systematic search was undertaken which found seventeen articles that compared invasively measured RAP with RV-E/e′ estimated RAP. Results commonly concerned pulmonary hypertension or advanced heart failure/transplantation populations. Reported receiver operating characteristic analyses showed reasonable diagnostic ability of RV-E/e′ for estimating RAP in patients with coronary artery disease and RV systolic dysfunction. The diagnostic ability of RV-E/e′ was generally poor in studies of paediatrics, heart failure and mitral stenosis, whilst results were equivocal in other diseases. Bland–Altman analyses showed good accuracy but poor precision of RV-E/e′ for estimating RAP, but were limited by only being reported in seven out of seventeen articles. This suggests that RV-E/e′ may be useful at a population level but not at an individual level for clinical decision making. Very little evidence was found about how atrial fibrillation may affect the estimation of RAP from RV-E/e′, nor about the independent prognostic ability of RV-E/e′. Recommended areas for future research concerning RV-E/e′ include; non-sinus rhythm, valvular heart disease, short and long term prognostic ability, and validation over a wide range of RAP.

Recommendations for hemodynamic monitoring for critically ill children-expert consensus statement issued by the cardiovascular dynamics section of the European Society of Paediatric and Neonatal Intensive Care (ESPNIC)

BACKGROUND

Cardiovascular instability is common in critically ill children. There is a scarcity of published high-quality studies to develop meaningful evidence-based hemodynamic monitoring guidelines and hence, with the exception of management of shock, currently there are no published guidelines for hemodynamic monitoring in children. The European Society of Paediatric and Neonatal Intensive Care (ESPNIC) Cardiovascular Dynamics section aimed to provide expert consensus recommendations on hemodynamic monitoring in critically ill children.

METHODS

Creation of a panel of experts in cardiovascular hemodynamic assessment and hemodynamic monitoring and review of relevant literature-a literature search was performed, and recommendations were developed through discussions managed following a Quaker-based consensus technique and evaluating appropriateness using a modified blind RAND/UCLA voting method. The AGREE statement was followed to prepare this document.

RESULTS

Of 100 suggested recommendations across 12 subgroups concerning hemodynamic monitoring in critically ill children, 72 reached "strong agreement," 20 "weak agreement," and 2 had "no agreement." Six statements were considered as redundant after rephrasing of statements following the first round of voting. The agreed 72 recommendations were then coalesced into 36 detailing four key areas of hemodynamic monitoring in the main manuscript. Due to a lack of published evidence to develop evidence-based guidelines, most of the recommendations are based upon expert consensus.

CONCLUSIONS

These expert consensus-based recommendations may be used to guide clinical practice for hemodynamic monitoring in critically ill children, and they may serve as a basis for highlighting gaps in the knowledge base to guide further research in hemodynamic monitoring.

Is Doppler echocardiography useful for estimating left ventricular filling pressures in pediatric heart transplant recipients?

LV E/E' ratio obtained using Doppler echocardiography is considered a surrogate for LV filling pressure in adults but has performed poorly in children. We hypothesized that LV E/E' ratio Z-score, adjusted for age, will relate more strongly to LV filling pressures than LV E/E' ratio in pediatric HT recipients. We analyzed 751 echocardiograms performed within 24 hours of a heart catheterization in 122 pediatric HT recipients (median age at HT 13 years, median 6 studies per patient). The primary end-point was PCWP, assessed both as a continuous and a binary variable. Associations with LV E/E' ratios and z-scores were assessed using generalized estimating equations models. PCWP, LV E/E' ratios (using E' from LV free wall, septum, and their average), and LV E/E' ratio Z-scores, all declined over time after HT. LV E/E' ratios and their Z-scores were significantly associated with PCWP assessed as a continuous variable (P < 0.001 for all); however, the relationship was weak (R² range, 0.083 to 0.121). LV E/E' ratios and their Z-scores were also significantly associated with PCWP as a binary variable (P < 0.001 for all) but with only modest ability to discriminate PCWP ≥15 mm Hg (c-statistic range, 0.660 to 0.695). The association between LV E/E' ratio and PCWP in pediatric HT recipients is modest. Using a LV E/E' ratio Z-score did not result in significantly improved association with PCWP. Current Doppler echocardiographic methods are unreliable for estimating LV filling pressures in pediatric HT recipients.

Utility of Echocardiography in the Assessment of Left Ventricular Diastolic Function and Restrictive Physiology in Children and Young Adults with Restrictive Cardiomyopathy: A Comparative Echocardiography-Catheterization Study

The aim of the study is to determine the utility of echocardiography in the assessment of diastolic function in children and young adults with restrictive cardiomyopathy (RCM). RCM is a rare disease with high mortality requiring frequent surveillance. Accurate, noninvasive echocardiographic measures of diastolic function may reduce the need for invasive catheterization. Single-center, prospective, observational study of pediatric and young adult RCM patients undergoing assessment of diastolic parameters by simultaneous transthoracic echocardiogram (TTE) and invasive catheterization. Twenty-one studies in 15 subjects [median (IQR) = 13.8 years (7.0-19.2), 60% female] were acquired with median left ventricular end-diastolic pressure (LVEDP) 21 (IQR 18-25) mmHg. TTE parameters of diastolic function, including pulmonary vein A wave duration (r _s  = 0.79) and indexed left atrial volume (r _s  = 0.49), demonstrated significant positive correlation, while mitral valve A (r _s  = -0.44), lateral e' (r _s  = -0.61) and lateral a' (r _s  = -0.61) velocities showed significant negative correlation with LVEDP. Lateral a' velocity (≤0.042 m/s) and pulmonary vein A wave duration (≥156 m/s) both had sensitivity and specificity ≥80% for LVEDP ≥ 20 mmHg. In pediatric and young adult patients with RCM, lateral a' velocity and pulmonary vein A wave duration predicted elevated LVEDP with high sensitivity and specificity; however, due to technical limitations the latter was reliably measured in 12/21 patients. These noninvasive parameters may have utility in identifying patients that require further assessment with invasive testing. These findings require validation in a multicenter prospective cohort prior to widespread clinical implementation.

Decline in ventricular function as a result of general anesthesia in pediatric heart transplant recipients

Echocardiography is frequently performed under anesthesia during procedures such as cardiac catheterization with EMB in pediatric HTx recipients. Anesthetic agents may depress ventricular function, resulting in concern for rejection. The aim of this study was to compare ventricular function as measured by echocardiography before and during GA in 17 pediatric HTx recipients. Nearly all markers of ventricular systolic function were significantly decreased under GA, including EF (-4.2% ±1.2, P < .01) and RV FAC (-0.05 ± 0.02, P = .04). Subjects in the first post-transplant year (n = 9) trended toward a more significant decrease in EF vs those beyond the first post-transplant year (n = 8; -6.0% ±1.2 vs -2.1 ± 2.0, P = .1). This information quantifies a decline in biventricular function that should be expected in pediatric HTx recipients while under GA and can assist the transplant clinician in avoiding unnecessary treatment of transient GA-induced ventricular dysfunction.

Doppler tissue imaging provides an estimate of pulmonary arterial pressure in children with pulmonary hypertension due to congenital intracardiac shunts

OBJECTIVE

The aim of this study is to determine the relationship between the cardiac catheterization findings and pulsed-wave (PW) Doppler and Doppler tissue imaging (DTI) in pulmonary arterial hypertension patients with congenital heart disease with intracardiac shunts.

DESIGN AND PATIENTS

The present study aims to determine the relationship between the cardiac catheterization findings and PW Doppler and Doppler tissue imaging (DTI) in patients who have pulmonary arterial hypertension patients due to congenital heart disease with intracardiac shunts. Echocardiographic measurements were performed at the catheter angiography laboratory with concurrent catheterization. Left and right ventricle inflow velocities were recorded with PW Doppler and DTI studies. Maximum tricuspid regurgitation velocity (TS) was recorded in cases with measurable levels by continuous-wave Doppler. Moreover, the correlations among the echocardiographic values and invasive hemodynamic measures such as systolic pulmonary arterial pressure (PAPsystolic), mean pulmonary arterial pressure (PAPmean), diastolic pulmonary arterial pressure (PAPdiastolic) and pulmonary vascular resistance index (PVRI) were evaluated.

RESULTS

A negative correlation was found between TE'/TA' and PAPsystolic, PAPdiastolic and PAPmean (P = 0.008, r = -0.480; P = 0.001, r = -0.584; P = 0.001, r = -0.567, respectively). ME/ME' was also found to be negatively correlated with PAPdiastolic, PAPmean and PVRI (P = 0.002, r = -0.556; P = 0.005, r = -0.502; P = 0.027, r = -0.411, respectively). The concurrent use of TE'/TA' (cut-off value <2.6) and TS had a sensitivity of 79% and a specificity of 93% for distinguishing between patients with healthy controls.

CONCLUSION

When used in conjunction with conventional methods, TE'/TA' has the highest sensitivity and specificity in distinguishing between patients and healthy controls.