Left ventricular myocardial performance index change for detection of acute cellular rejection in pediatric heart transplantation

Rejection surveillance in pediatric heart transplant recipients: Critical reflection on the role of frequent and long-term routine surveillance endomyocardial biopsies and comprehensive review of non-invasive rejection screening tools

BACKGROUND

Despite significant medical advances in the field of pediatric heart transplantation (HT), acute rejection remains an important cause of morbidity and mortality. Endomyocardial biopsy (EMB) remains the gold-standard method for diagnosing rejection but is an invasive, expensive, and stressful process. Given the potential adverse consequences of rejection, routine post-transplant rejection surveillance protocols incorporating EMB are widely employed to detect asymptomatic rejection. Each center employs their own specific routine rejection surveillance protocol, with no consensus on the optimal approach and with high inter-center variability. The utility of high-frequency and long-term routine surveillance biopsies (RSB) in pediatric HT has been called into question.

METHODS

Sources for this comprehensive review were primarily identified through searches in biomedical databases including MEDLINE and Embase.

RESULTS

The available literature suggests that the diagnostic yield of RSB is low beyond the first year post-HT and that a reduction in RSB intensity from high-frequency to low-frequency can be done safely with no impact on early and mid-term survival. Though there are emerging non-invasive methods of detecting asymptomatic rejection, the evidence is not yet strong enough for any test to replace EMB.

CONCLUSION

Overall, pediatric HT centers in North America should likely be doing fewer RSB than are currently performed. Risk factors for rejection should be considered when designing the optimal rejection surveillance strategy. Noninvasive testing including emerging biomarkers may have a complementary role to aid in safely reducing the need for RSB.

Early findings after integration of donor-derived cell-free DNA into clinical care following pediatric heart transplantation

BACKGROUND

Endomyocardial biopsy (EMB) is costly and discomforting yet remains a key component of surveillance after pediatric heart transplantation (HT). Donor-derived cell-free DNA (dd-cfDNA) has been histologically validated with high negative predictive value, offering an alternative to surveillance EMB (sEMB).

METHODS

We implemented an alternative surveillance protocol using commercially available dd-cfDNA assays in place of sEMB after pediatric HT. Recipients ≧7 months post-HT with reassuring clinical assessment were referred for dd-cfDNA. When not elevated above the manufacturers' threshold, sEMB was deferred. Subsequent clinical status and results of follow-up EMB were analyzed.

RESULTS

Over 17 months, 58 recipients [34% female, median age at HT 3.1 years (IQR 0.6-10.6)] had dd-cfDNA assessed per protocol. Median age was 14.8 years (8.4-18.3) and time from HT 6.0 years (2.2-11.2). Forty-seven (81%) had non-elevated dd-cfDNA and 11 (19%) were elevated. During a median of 8.7 months (4.2-15), all are alive without allograft loss/new dysfunction. Among those with non-elevated dd-cfDNA, 24 (51%) had subsequent sEMB at 12.1 months (6.9-12.9) with 23 showing no acute rejection (AR): grade 0R/pAMR0 (n = 16); 1R(1A)/pAMR0 (n = 7). One had AR (grade 2R(3A)/pAMR0) on follow-up sEMB after decreased immunosuppression following a diagnosis of PTLD. All 11 with elevated dd-cfDNA had reflex EMB at 19 days (12-32) with AR in 4: grade 1R(1B-2)/pAMR0 (n = 3); 1R(1B)/pAMR2 (n = 1).

CONCLUSIONS

dd-cfDNA assessment in place of selected, per-protocol EMB decreased surveillance EMB by 81% in our pediatric HT recipient cohort with no short-term adverse outcomes. Individual center approach to surveillance EMB will influence the utility of these findings.

Speckle-tracking-based global longitudinal and circumferential strain detect early signs of antibody-mediated rejection in heart transplant patients

AIMS

Acute rejection is an important cause of mortality after heart transplant (HTx), but symptoms develop only when myocardial damage is already extensive. We sought to investigate if echocardiographic parameters can detect and predict an acute cellular rejection (ACR) or antibody-mediated rejection (AMR) episode in HTx patients.

METHODS AND RESULTS

Data of 403 consecutive HTx recipients between 2003 and 2020 from our centre were reviewed. Patients with severe ACR (n = 10) and AMR (n = 7) were identified. Each HTx patient presenting with rejection was matched to a control HTx patient. Echocardiographic variables from the moment of rejection and 3, 6, and 12 months before were analysed and compared among groups. At acute rejection episode, patients with rejection had lower values of global longitudinal strain (GLS), global circumferential strain (GCS), and left ventricular ejection fraction (LVEF) compared to controls. HTx patients with AMR showed a progressive decline of GLS and GCS in the months preceding acute rejection, while controls and ACR patients had stable strain values except for the moment of rejection. In our cohort, a GLS cut-off lower than 15.5% and a GCS cut-off lower than 15.2% could distinguish with a sensitivity and specificity of 100.0% AMR from controls 3 months before rejection. LVEF and other conventional echo parameters could not differentiate among groups.

CONCLUSION

GLS and GCS show a progressive decrease months before AMR becomes clinically apparent. Our data suggest that global strain assessment by echocardiography allows an early detection of a developing AMR, which could improve the clinical management of HTx patients.

Pediatric heart transplantation: how to manage problems affecting long-term outcomes?

Since the initial International Society of Heart Lung Transplantation registry was published in 1982, the number of pediatric heart transplantations has increased markedly, reaching a steady state of 500-550 transplantation annually and occupying up to 10% of total heart transplantations. Heart transplantation is considered an established therapeutic option for patients with end-stage heart disease. The long-term outcomes of pediatric heart transplantations were comparable to those of adults. Issues affecting long-term outcomes include acute cellular rejection, antibody-mediated rejection, cardiac allograft vasculopathy, infection, prolonged renal dysfunction, and malignancies such as posttransplant lymphoproliferative disorder. This article focuses on medical issues before pediatric heart transplantation, according to the Korean Network of Organ Sharing registry and as well as major problems such as graft rejection and cardiac allograft vasculopathy. To reduce graft failure rate and improve long-term outcomes, meticulous monitoring for rejection and medication compliance are also important, especially in adolescents.

Early Acute Graft Rejection in a Heart Transplanted Child with Dilated Cardiomyopathy

Dilated cardiomyopathy (DCM) is the most common type of cardiomyopathy in children. Heart transplantation is considered standard therapy in dilated cardiomyopathy with end-stage heart failure. We present a case of a 15-year-old patient diagnosed with DCM in the neonatal period, who underwent heart transplantation for end-stage heart failure. Despite the use of induction therapy, the endomyocardial biopsy performed at two weeks post-transplant revealed mixed moderate cellular (2R) and humoral (pAMR2) allograft rejection. Aggressive rejection treatment was initiated with good outcome. Besides endomyocardial biopsy, advanced echocardiography can also be a valuable noninvasive tool for rejection assessment.

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.

Cardiac function in children with premature ventricular contractions: the effect of omega-3 polyunsaturated fatty acid supplementation

BACKGROUND

Premature ventricular contractions are accepted as benign in structurally normal hearts. However, reversible cardiomyopathy can sometimes develop. Omega-3 polyunsaturated fatty acids have anti-arrhythmic properties in animals and humans.AimWe evaluated left ventricular function in children with premature ventricular contractions with normal cardiac anatomy and assessed the impact of omega-3 fatty acid supplementation on left ventricular function in a prospective trial.

METHODS

A total of 25 patients with premature ventricular contraction, with more than 2% premature ventricular contractions on 24-hour Holter electrocardiography, and 30 healthy patients were included into study. All patients underwent electrocardiography, left ventricular M-mode echocardiography, and myocardial performance index testing. Patients with premature ventricular contraction were given omega-3 fatty acids at a dose of 1 g/day for 3 months, and control echocardiography and 24-hour Holter electrocardiography were performed. Neither placebo nor omega-3 fatty acids were given to the control group.

RESULTS

Compared with the values of the control group, the patients with premature ventricular contraction had significantly lower fractional shortening. The myocardial performance index decreased markedly in the patient groups. The mean heart rate and mean premature ventricular contraction percentage of Group 2 significantly decreased in comparison with their baseline values after the omega-3 supplementation.

CONCLUSION

In conclusion, premature ventricular contractions can lead to systolic cardiac dysfunction in children. Omega-3 supplementation may improve cardiac function in children with premature ventricular contractions. This is the first study conducted in children to investigate the possible role of omega-3 fatty acid supplementation on treatment of premature ventricular contractions.

Effect of food intake on myocardial performance index

Background

Myocardial performance index (MPI) has been investigated in a variety of populations, but the effect of food intake has not been evaluated. We assessed whether myocardial performance index is affected by food intake in healthy subjects.

Methods

Twenty-three healthy subjects aged 25.6 ± 4.5 years were investigated. MPI was measured before, 30 min after, and 110 min after a standardized meal.

Results

MPI decreased significantly (P < 0.05) from fasting values 30 min after the meal, and had almost returned to baseline after 110 min. MPI decreased from 0.28 ± 0.06 (fasting) to 0.20 ± 0.07 30 min after eating. At 110 min after eating the index value was almost back to the baseline value 0.26 ± 0.06. (P = 0.15).

Conclusions

This study shows that myocardial performance index is affected by food intake in healthy subjects.

Reducing Fluoroscopic Radiation Exposure During Endomyocardial Biopsy in Pediatric Transplant Recipients

Endomyocardial biopsy (EMB) with fluoroscopy is used for rejection surveillance in pediatric heart transplantation. Lowering frame rate may reduce radiation, but decreases temporal resolution and image quality. We undertook a quality initiative reducing frame rate from 10 frames per second (FPS) to 5 FPS. To assess whether lowering frame rate can reduce radiation exposure without compromising safety, data on EMBs from 9/2009 to 4/2013 without angiography or intervention were reviewed. Effective dose was calculated from dose area product (DAP) and fluoroscopy time. Complications were reviewed. Independent t test compared pre- and post-data and a general linear model were used to control for confounders. Paired t test of most proximate data was used for pts with EMB before and after our change. Eighty-six patients had 543 EMB. After adjusting for weight, attending, and presence of a fellow, the lower FPS group had a 60.3% reduction in DAP (p < 0.0001) and 53.8% drop in effective dose (p < 0.0001). Fluoroscopy time did not differ. Twenty-eight pts had EMBs both before and after the FPS change. Pair-wise analysis of this group demonstrated a 33% reduction in DAP (p < 0.05) and 37% drop in effective dose (p < 0.01), without difference in fluoroscopy time. No patient had an increase in TR > 1 grade by ECHO. There were no deaths or perforations. Lowering the frame rate reduces radiation exposure by >50% without compromising safety. Efforts to further minimize radiation exposure of this vulnerable population should be considered.

Evaluation of myocardial function in pediatric patients with transposition of great arteries after arterial switch operation

OBJECTIVE

An arterial switch operation converts the left ventricle (LV) into the systemic ventricle, replacing the right ventricle (RV), which is the systemic ventricle during the prenatal period. The procedure is performed in patients with arterial transposition and those in whom a coronary reimplantation procedure is performed. Therefore, the adaptation of LV and RV to the arterial switch operations is an interesting issue. This study aimed to evaluate systolic and diastolic functions in the LV and RV myocardium using echocardiography in pediatric patients with transposed great arteries after an arterial switch operation.

METHODS

This observational case control study included 28 patients and 20 gender-and age-matched healthy controls. A group study was performed using patients who were followed for at least 6 months after the operation and who visited the pediatric cardiology outpatient between October 2009 and May 2011. Systolic and diastolic parameters, LV and RV myocardial performance index (MPI) values, and left atrium (LA) volume index were assessed in both groups.

RESULTS

The LV MPI and tricuspid valve (TV) E/Ea ratio measured using pulsed-wave Doppler were higher in the patient group than in the control group. The TV E/A ratio and late velocity of lateral mitral annulus (Aa) and systolic velocity (Sa)-early diastolic velocity (Ea)-late velocity (Aa) of the septal mitral annulus and systolic velocity (Sa)-early diastolic velocity (Ea)-late velocity (Aa) of the lateral tricuspid annulus were lower in the patient group than in the control group.

CONCLUSION

Considering the present study's findings obtained during short-to mid-term follow-up, the RV tissue Doppler flows and the LV MPI were found impaired.

Intraoperative transesophageal echocardiographic assessment of left ventricular Tei index in congenital heart disease

BACKGROUND

Use of the Tei index has not been described to assess myocardial function before or after surgery in pediatric patients. This study was designed to evaluate the left ventricular (LV) function using the Tei index pre- and post-cardiopulmonary bypass in patients with lesion that result in a volume loaded right ventricle (RV).

METHODS

Retrospective data on 55 patients who underwent repair of a cardiac defect were analyzed. Patients with volume overload RV (n = 15) were compared to patients without volume overload but with other cardiac defects (n = 40). We reviewed pre- and post-operative LV myocardial performance index (Tei index). Tei index was obtained from transesophageal Doppler echocardiogram.

RESULTS

Patients with right heart volume overload, the mean preoperative Tei index was 0.6, with a postoperative mean decrease of 0.207 (P = 0.014). Patients without right heart volume overload, the mean preoperative Tei was 0.48 with no significant postoperative change (P = 0.82).

CONCLUSION

Pre- and post-operative transesophageal echocardiogram assessment provides an easy and quick way of evaluating LV function intra-operatively using LV Tei index. Preoperative LV Tei index was greater in the RV volume overload defects indicating diminished LV global function. This normalized in the immediate postoperative period, implying an immediate improvement in LV function. In patients without right heart volume load, consist of other cardiac defects, demonstrated no changes in the pre- and post-operative LV Tei. This implies that LV function was similar after the surgery.

Diagnostic performance of echocardiography for the detection of acute cardiac allograft rejection: a systematic review and meta-analysis

Objective

Many studies have addressed the diagnostic performance of echocardiography to evaluate acute cardiac allograft rejection compared with endomyocardial biopsy. But the existence of heterogeneity limited its clinical application. Thus, we conducted a comprehensive, systematic literature review and meta-analysis for the purpose.

Methods

Studies prior to September 1, 2014 identified by Medline/PubMed, EMBASE and Cochrance were examined by two independent reviews. We conducted meta-analysis by using Meta-DiSc 1.4 software. An assessment tool of QUADAS-2 was applied to evaluate the risk of bias and applicability of the studies.

Results

Thirty studies met the inclusion criteria of meta-analysis. The four parameters of pressure half time, isovolumic relaxation time, index of myocardial performance and late diastolic mitral annular motion velocity were included in the meta-analysis, with a pooled diagnostic odds ratio of 10.43, 6.89, 15.95 and 5.68 respectively, and the area under the summary receiver operating characteristic curves value of 0.829, 0.599, 0.871 and 0.685 respectively.

Conclusion

The meta-analysis and systematic review demonstrate that no single parameter of echocardiography showed a reliable diagnostic performance for acute cardiac allograft rejection. A result of echocardiography for ACAR should be comprehensively considered by physicians in the context of clinical presentations and imaging feature.