Biopsy-induced flail tricuspid leaflet and tricuspid regurgitation following orthotopic cardiac transplantation

Incidence of Acute Rejection Compared With Endomyocardial Biopsy Complications for Heart Transplant Patients in the Contemporary Era

BACKGROUND

The reference standard of detecting acute rejection (AR) in adult heart transplant (HTx) patients is an endomyocardial biopsy (EMB). The majority of EMBs are performed in asymptomatic patients. However, the incidence of treated AR compared with EMB complications has not been compared in the contemporary era (2010-current).

METHODS

The authors retrospectively analyzed 2769 EMBs obtained in 326 consecutive HTx patients between August 2019 and August 2022. Variables included surveillance versus for-cause indication, recipient and donor characteristics, EMB procedural data and pathological grades, treatment for AR, and clinical outcomes.

RESULTS

The overall EMB complications rate was 1.6%. EMBs performed within 1 mo after HTx compared with after 1 mo from HTx showed significantly increased complications (OR, 12.74, P  < 0.001). The treated AR rate was 14.2% in the for-cause EMBs and 1.2% in the surveillance EMBs. We found the incidence of AR versus EMB complications was significantly lower in the surveillance compared with the for-cause EMB group (OR, 0.05, P  < 0.001). We also found the incidence of EMB complications was higher than treated AR in surveillance EMBs.

CONCLUSIONS

The yield of surveillance EMBs has declined in the contemporary era, with a higher incidence of EMB complications compared with detected AR. The risk of EMB complications was highest within 1 mo after HTx. Surveillance EMB protocols in the contemporary era may need to be reevaluated.

Outcomes of tricuspid valve prostheses after heart transplantation: a systematic review

Tricuspid regurgitation (TR) is the most common valvular pathology after heart transplantation (HTx) and endomyocardial biopsy (EMB) remains responsible for the majority of cases due to the high probability of structural valve damage. The aim of the present review was to describe the results of surgical management of severe tricuspid regurgitation through tricuspid valve replacement (TVR) after a previous HTx. A systematic review was conducted by searching Pubmed, ScienceDirect, SciELO, DOAJ, and Cochrane databases until June 2023 for publications reporting patients undergoing TVR surgery after a previous HTx. If no right heart valve surgery was undertaken, or a heterotopic heart transplant was performed, or if the concomitant procedure was performed during the transplant itself, the paper was excluded. Twenty articles met our inclusion criteria out of 1532 potentially eligible studies, with a total of 300 patients. Mean age was 55.1 ± 9.6 years, and 85.1% were male. The mean number of EMB per patient was 31.1 ± 5.5 with a mean time between HTx and TVR of 7.64 ± 3.31 years. Bioprostheses were used in 83.3% of cases and 75.0% of patients with a bioprosthesis were reported as alive at last follow-up. Tricuspid valve repair is a valuable option, but these patients will be susceptible to recurrent TR after EMB. TVR with a bioprosthesis may provide the optimal solution for this subset of patients, as EMB is not feasible with a mechanical valve.

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.

Benefit versus Risk of Endomyocardial Biopsy for Heart Transplant Patients in the Contemporary Era

Background

The reference standard of detecting acute rejection (AR) in adult heart transplant (HTx) patients is an endomyocardial biopsy (EMB). The majority of EMBs are performed in asymptomatic patients. However, the benefit of diagnosing and treating AR compared to the risk of EMB complications has not been compared in the contemporary era (2010-current).

Methods

The authors retrospectively analyzed 2,769 EMB obtained in 326 consecutive HTx patients between August 2019 and August 2022. Variables included surveillance versus for cause indication, recipient and donor characteristics, EMB procedural data and pathologic grades, treatment for AR, and clinical outcomes.

Results

The overall EMB complication rate was 1.6%. EMBs performed within 1 month after HTx compared to after 1 month from HTx showed significantly increased complications (OR = 12.74, p < 0.001). The treated AR rate was 14.2% in the for cause EMBs and 1.2% in the surveillance EMBs. We found the benefit/risk ratio was significantly lower in the surveillance compared to the for cause EMB group (OR = 0.05, p < 0.001). We also found the benefit to be lower than risk in surveillance EMBs.

Conclusions

The yield of surveillance EMBs has declined, while for cause EMBs continued to demonstrate a high benefit/risk ratio. The risk of EMB complications was highest within 1 month after HTx. Surveillance EMB protocols in the contemporary era may need to be re-evaluated.

Elevated Cardiac Troponin to Detect Acute Cellular Rejection After Cardiac Transplantation: A Systematic Review and Meta-Analysis

Cardiac troponin is well known as a highly specific marker of cardiomyocyte damage, and has significant diagnostic accuracy in many cardiac conditions. However, the value of elevated recipient troponin in diagnosing adverse outcomes in heart transplant recipients is uncertain. We searched MEDLINE (Ovid), Embase (Ovid), and the Cochrane Library from inception until December 2020. We generated summary sensitivity, specificity, and Bayesian areas under the curve (BAUC) using bivariate Bayesian modelling, and standardised mean differences (SMDs) to quantify the diagnostic relationship of recipient troponin and adverse outcomes following cardiac transplant. We included 27 studies with 1,684 cardiac transplant recipients. Patients with acute rejection had a statistically significant late elevation in standardised troponin measurements taken at least 1 month postoperatively (SMD 0.98, 95% CI 0.33–1.64). However, pooled diagnostic accuracy was poor (sensitivity 0.414, 95% CrI 0.174–0.696; specificity 0.785, 95% CrI 0.567–0.912; BAUC 0.607, 95% CrI 0.469–0.723). In summary, late troponin elevation in heart transplant recipients is associated with acute cellular rejection in adults, but its stand-alone diagnostic accuracy is poor. Further research is needed to assess its performance in predictive modelling of adverse outcomes following cardiac transplant.

Systematic Review Registration: identifier CRD42021227861

Epidemiological Study of Tricuspid Regurgitation After Cardiac Transplantation. Does it Influence Survival?

Background: Tricuspid valve disease is the most frequent valvulopathy after heart transplantation (HTx). Evidence for the negative effect of post-transplant tricuspid regurgitation (TR) on survival is contradictory. The aim of this study was to analyze the causes of post-transplant TR and its effect on overall mortality. Methods: This is a retrospective observational study of all transplants performed in two Spanish centers (1009 patients) between 2000 and 2019. Of the total number of patients, 809 had no TR or mild TR and 200 had moderate or severe TR. The etiology of TR was analyzed in all cases. Results: The prevalence of moderate and severe TR was 19.8%. The risk of mortality was greater when TR was caused by early primary graft failure (PGF) or rejection (p < 0.05). TR incidence was related to etiology: incidence of PGF-induced TR was higher in the first period, while TR due to rejection and undefined causes occurred more frequently in three periods: in the first year, in the 10-14-year period following HTx, and in the long term (16-18 years). In the multivariable analysis, TR was significantly associated with mortality/retransplantation (HR:1.04, 95% CI:1.01-1.07, p:0.02). Conclusion: The development of TR after HTx is relatively frequent. The annual incidence depends on TR severity and etiology. The risk of mortality is greater in severe TR due to PGF or rejection.

Initiation of noninvasive surveillance for allograft rejection in heart transplant patients > 1 year after transplant

BACKGROUND

Gene expression profiling (GEP) and donor-derived, cell-free DNA (dd-cfDNA) measurement are alternative methods to endomyocardial biopsy (EMB) to monitor for rejection following heart transplantation. We aim to describe our use of GEP and dd-cfDNA in heart transplant recipients > 1-year post-transplantation.

METHODS

This is a single-center, retrospective study in post-transplant recipients. For patients who were > 1-year post-transplantation and deemed to be at elevated clinical risk for rejection, we collected both GEP and dd-cfDNA every 3 months. Baseline characteristics including GEP, dd-cfDNA levels, rejection episodes, and number of biopsies were obtained.

RESULTS

Since July 2019, there were 18 patients being followed with GEP and dd-cfDNA who were > 1-year post-transplantation. Nine EMBs had been performed in seven patients due to as follows; three due to elevated GEP ({greater than or equal to} 34), one due to elevated dd-cfDNA ({greater than or equal to} .20%), two due to elevations of both GEP and dd-cfDNA, two due to clinical rejection and one to follow up a post rejection episode. One of the two biopsies due to elevations of both GEP and dd-cfDNA showed acute cellular rejection grade 2R. None of the biopsies due to either an elevation in the GEP or dd-cfDNA revealed any significant rejection.

CONCLUSION

In this study, the use of both GEP and dd-cfDNA led to an increased number of EMB in patients > 1-year post-transplantation. Further studies are needed to validate these findings and evaluate long-term consequences of these diagnostic tests in this population.

Marginal donors and organ shortness: concomitant surgical procedures during heart transplantation: a literature review

Heart transplantation represents the gold standard for end-stage heart failure. However, due to the increasing demand and the shortage of available organs, donor supply remains the main limitation. Marginal donor hearts in high-risk candidates who do not meet standard listing criteria are the only alternative when life expectancy is limited, but their use is still debated. Surgical correction of detected coronary lesions or valvular heart defects allows further enlargement of the number of available organs. In this article, we offer a literature review on this topic and report two marginal donor hearts with angiography evidence of coronary stenosis and preserved ventricular function, which underwent concomitant myocardial revascularization during heart implantation.

Functional tricuspid valve insufficiency after cardiac transplantation: Which factor is the most important?

Objectives

Tricuspid insufficiency (TI) is the most common valvular complication following orthotopic heart transplantation (HTx) and in serious cases is associated with increased mortality. In this study, we analyze the possible variables influencing TI following HTx and aim to identify the most important risk factors and mechanisms responsible for functional TI development and progression.

Methods

We identified the incidence of TI within our institute in 857 of 1515 patients who underwent HTx using the biatrial anastomosis technique in the years between 1986 and 2010. The risk factors that could influence TI were retrospectively analyzed in detail in a representative group of 152 patients with identical TI distribution as found in the entire program. Patients of the group were subdivided into 2 groups according to the severity of TI: patients with TI grade ≤2 and those with TI grade >2. Impact on long-term survival (>15 years) was assessed.

Results

In univariable analysis, study variables such as age of recipient (P = .027), donor to recipient right atrium anterior wall ratio (P < .001), tricuspid annulus anterior to septal leaflet excursion ratio (P = .001), dialysis (P = .026), and total biopsy number (P = .003) showed significant differences. The variables, height of recipient (P = .080), body mass index donor to body mass index recipient ratio (P = .080), and number of biopsies with more than moderate grade (P = .067) showed a trend toward significance in the development of severe TI after HTx. In multivariable analysis, we found an independent significant association between TI after HTx and donor to recipient right atrium anterior wall ratio, number of biopsies, and dialysis.

Conclusions

Changes in tricuspid annulus geometry, number of biopsies, and dialysis are the most important risk factors for the development and progression of TI following cardiac transplantation. It could be prevented using modified operative techniques, noninvasive diagnostic modalities, and intensified ultrafiltration. In patients with biatrial anastomosis technique with generous atrial cuff, the presence of TI greater than grade 2 did not impact long-term survival.

A Noninvasive and Donor-independent Method Simultaneously Monitors Rejection and Infection in Patients With Organ Transplant

BACKGROUND

Rejection and infection are 2 major complications affecting the health and survival of patients receiving an allograft organ transplantation. We describe a diagnostic assay that simultaneously monitors for rejection and infection in recipients of kidney transplant by sequencing of cell-free DNA (cfDNA) in plasma.

METHODS

By using cfDNA in plasma, we established a noninvasive method that simultaneously monitors rejection and infection in patients with a history of organ transplant. A total of 6200 single-nucleotide polymorphisms were captured by liquid hybridization and sequenced by next-generation sequencing. The donor-derived cfDNA (ddcfDNA) level was calculated based on maximum likelihood estimation, without relying on the donor's genotype. We also analyzed the nonhuman cfDNA to test for infections in the patients' plasma.

RESULTS

Artificial ddcfDNA levels quantified by a donor-dependent and donor-independent algorithm were significantly correlated, with the multivariate coefficient of determination, or R² value, of 0.999. This technique was applied on 30 patients (32 samples) after kidney transplantation, and a significant difference was observed on the ddcfdNA levels between nonrejection and rejection. Furthermore, 1 BK virus infection and 1 cytomegalovirus infection were revealed by this method, and the enrichment efficiency of the viral sequences was 114 and 489 times, respectively, which are consistent with clinical results.

CONCLUSION

This method can be used to simultaneously monitor for acute rejection as well as a broad spectrum of infections for patients of allograft organ transplant because it provides comprehensive information for clinicians to optimize immunosuppression therapy.

Noninvasive detection of graft injury after heart transplant using donor-derived cell-free DNA: A prospective multicenter study

Standardized donor-derived cell-free DNA (dd-cfDNA) testing has been introduced into clinical use to monitor kidney transplant recipients for rejection. This report describes the performance of this dd-cfDNA assay to detect allograft rejection in samples from heart transplant (HT) recipients undergoing surveillance monitoring across the United States. Venous blood was longitudinally sampled from 740 HT recipients from 26 centers and in a single-center cohort of 33 patients at high risk for antibody-mediated rejection (AMR). Plasma dd-cfDNA was quantified by using targeted amplification and sequencing of a single nucleotide polymorphism panel. The dd-cfDNA levels were correlated to paired events of biopsy-based diagnosis of rejection. The median dd-cfDNA was 0.07% in reference HT recipients (2164 samples) and 0.17% in samples classified as acute rejection (35 samples; P = .005). At a 0.2% threshold, dd-cfDNA had a 44% sensitivity to detect rejection and a 97% negative predictive value. In the cohort at risk for AMR (11 samples), dd-cfDNA levels were elevated 3-fold in AMR compared with patients without AMR (99 samples, P = .004). The standardized dd-cfDNA test identified acute rejection in samples from a broad population of HT recipients. The reported test performance characteristics will guide the next stage of clinical utility studies of the dd-cfDNA assay.

Flail Tricuspid Leaflet During the Percutaneous Closure of Post-Myocardial Infarction Ventricular Septal Defect

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A post-MI ventricular septal defect is a complication of ST-elevation MI.

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Iatrogenic tricuspid regurgitations have not been reported after percutaneous closure.

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Care should be taken with the degree of tricuspid regurgitation to prevent iatrogenic tricuspid injury.

Lower frequency routine surveillance endomyocardial biopsies after heart transplantation

In heart transplantation (HTx) patients, routine surveillance endomyocardial biopsies (rsEMB) are recommended for the detection of early cardiac allograft rejection. However, there is no consensus on the optimal frequency of rsEMB. Frequent rsEMB have shown a low diagnostic yield in the new era of potent immunosuppressive regimen. Efficacy and safety of lower frequency rsEMB have not been investigated so far. In this retrospective, single centre, observational study we evaluated 282 patients transplanted between 2004 and 2014. 218 of these patients were investigated by rsEMB and symptom-triggered EMB (stEMB). We evaluated EMB results, complications, risk factors for rejection, survival 1 and 5 years as well as incidence of cardiac allograft vasculopathy (CAV) 3 years after HTx. A mean of 7.1 ± 2.5 rsEMB were conducted per patient within the first year after HTx identifying 7 patients with asymptomatic and 9 patients with symptomatic acute rejection requiring glucocorticoide pulse therapy. Despite this relatively low frequency of rsEMB, only 6 unscheduled stEMB were required in the first year after HTx leading to 2 additional treatments. In 6 deaths among all 282 patients (2.1%), acute rejection could not be ruled out as a potential underlying cause. Overall survival at 1 year was 78.7% and 5-year survival was 74%. Incidence of CAV was 17% at 3-year follow-up. Morbidity and mortality of lower frequency rsEMB are comparable with data from the International Society for Heart and Lung Transplantation (ISHLT) registry. Consensus is needed on the optimal frequency of EMB.

Current Expectations for Cardiac Transplantation in Patients With Congenital Heart Disease

Congenital heart disease accounts for 40% of pediatric heart transplants and presents unique challenges to the transplant team. Suitability for transplantation is defined in part by degree of sensitization, pulmonary vascular resistance, and hepatic reserves. The incremental transplant risk for patients with congenital heart disease occurs within the first 3 months, after which survival is equivalent to transplantation for cardiomyopathy. Single ventricle with prior palliation, and especially the failing Fontan, carry the highest risk for transplantation and are least amenable to bridging with mechanical circulatory support. More effective bridging to transplant with mechanical circulatory support will require improvements in the adverse event profile of available pumps and the introduction of miniaturized continuous flow technology. The major barriers to routine long-term survival are chronic allograft failure and allograft vasculopathy. Despite these many challenges, continuing improvements in the care of pediatric heart transplant patients have pushed the median posttransplant survival past 15 years for children and to 20 years for infants.

Different types of tricuspid flail: Case reports and review of the literature

Tricuspid regurgitation (TR) is a common Doppler echocardiographic finding resulting from either intrinsic valve abnormalities or functional malcoaptation of structurally normal valves. TR caused by flail leaflets is most often post-traumatic, is caused by endocarditis or is a consequence of a myxomatously degenerated valve. The clinical presentation is severe and is characterized by excess mortality and high morbidity. Flail leaflets are reliably diagnosed using 2-dimensional and 3-dimensional echocardiography.

Repair of early posttransplant endomyocardial biopsy-related tricuspid regurgitation in a child

We describe surgical repair of symptomatic tricuspid valve regurgitation in the early posttransplant period in a small child. The tricuspid valve regurgitation was due to injury to the valve and chordal apparatus during surveillance endomyocardial biopsy. The described surgical technique produced durable improvement in valve function.

Cost-Effectiveness of Routine Surveillance Endomyocardial Biopsy After 12 Months Post–Heart Transplantation

Background—

Despite low risk of late rejection after heart transplant (HT), surveillance endomyocardial biopsies (EMBs) are often continued for years. We assessed the cost-effectiveness of routine EMB after 12 months post-HT.

Methods and Results—

Markov model compared the following surveillance EMB strategies to baseline strategy of stopping EMB 12 months post-HT: (1) every 4 months during year 2 post-HT, (2) every 6 months during year 2, (3) every 4 months for years 2 to 3, and (4) every 6 months for years 2 to 3. Patients entered the model 12 months post-HT and were followed until 36 months. In all strategies, patients had EMB with symptoms; in biopsy strategies after 12 months, EMB was also performed as scheduled regardless of symptoms. One-way and Monte Carlo sensitivity analyses were performed. Stopping EMB at 12 months was dominant (more effective, less costly), saving $2884 per patient compared with the next best strategy (every 6 months for year 2) and gaining 0.0011 quality-adjusted life-years. Increasing the annual risk of asymptomatic rejection in years 2 to 3 from previously reported 2.5% to 8.5% resulted in the biopsy every 6 months for year 2 strategy gaining 0.0006 quality-adjusted life-years, but cost $4 913 599 per quality-adjusted life-year gained. EMB for 12 months was also no longer dominant when mortality risk from untreated asymptomatic rejection approached 11%; competing strategies still cost >$200 000 per quality-adjusted life-year as that risk approached 99%.

Conclusions—

Surveillance EMB for 12 months post-HT is more effective and less costly than EMB performed after 12 months, unless risks of asymptomatic cellular rejection and its mortality are strikingly higher than previously observed.

Issues in solid-organ transplantation in children: translational research from bench to bedside

In this review, we identify important challenges facing physicians responsible for renal and cardiac transplantation in children based on a review of the contemporary medical literature. Regarding pediatric renal transplantation, we discuss the challenge of antibody-mediated rejection, focusing on both acute and chronic antibody-mediated rejection. We review new diagnostic approaches to antibody-mediated rejection, such as panel-reactive antibodies, donor-specific cross-matching, antibody assays, risk assessment and diagnosis of antibody-mediated rejection, the pathology of antibody-mediated rejection, the issue of ABO incompatibility in renal transplantation, new therapies for antibody-mediated rejection, inhibiting of residual antibodies, the suppression or depletion of B-cells, genetic approaches to treating acute antibody-mediated rejection, and identifying future translational research directions in kidney transplantation in children. Regarding pediatric cardiac transplantation, we discuss the mechanisms of cardiac transplant rejection, including the role of endomyocardial biopsy in detecting graft rejection and the role of biomarkers in detecting cardiac graft rejection, including biomarkers of inflammation, cardiomyocyte injury, or stress. We review cardiac allograft vasculopathy. We also address the role of genetic analyses, including genome-wide association studies, gene expression profiling using entities such as AlloMap®, and adenosine triphosphate release as a measure of immune function using the Cylex® ImmuKnow™ cell function assay. Finally, we identify future translational research directions in heart transplantation in children.

Tricuspid valve regurgitation after orthotopic heart transplantation: prevalence and etiology

Background. Tricuspid valve regurgitation (TR) after orthotopic heart transplantation (OHT) is common. The aims of this study were to determine the prevalence of TR after OHT, to examine the correlation between its development and various variables, and to determine its outcomes. Methods. All 163 OHT patients who were followed up between 1988 and 2009 for a minimal period of 12 months were divided into those with no TR/mild TR and those with at least mild-moderate TR, as assessed by doppler echocardiography. These groups were compared regarding preoperative hemodynamic variables, surgical technique employed, number of endomyocardial biopsies, number of acute cellular rejections, incidence of graft vasculopathy, and clinical outcomes. Results. At the end of the followup (average 8.2 years) significant TR was evident in 14.1% of the patients. The development of late TR was found by univariate, but not multivariate, analysis to be significantly correlated with the biatrial surgical technique (P < 0.01) and the presence of graft vasculopathy (P < 0.001). TR development was found to be correlated with the need for tricuspid valve surgery but not with an increased mortality. Conclusions. The development of TR after OHT may be related to the biatrial anastomosis technique and to graft vasculopathy.

[Complications of endomyocardial biopsy after heart transplantation: a lesser evil]

Endomyocardial biopsy is still the principal method for diagnosing cardiac allograft rejection. However, this procedure can be associated, albeit rarely, with potentially serious complications. We describe the case of a patient with extensive anterior myocardial infarction without revascularization, who developed cardiogenic shock and required heart transplantation. Post-transplantation, a coronary artery fistula to the right ventricle associated with an aneurysm and two restrictive ventricular septal defects were detected.

Endomyocardial biopsy and selective coronary angiography are low-risk procedures in pediatric heart transplant recipients: results of a multicenter experience

BACKGROUND

No prior reports documenting the safety and diagnostic yield of cardiac catheterization and endomyocardial biopsy (EMB) in heart transplant recipients include multicenter data.

METHODS

Data on the safety and diagnostic yield of EMB procedures performed in heart transplant recipients were recorded in the Congenital Cardiac Catheterization Outcomes Project database at 8 pediatric centers during a 3-year period. Adverse events (AEs) were classified according to a 5-level severity scale. Generalized estimating equation models identified risk factors for high-severity AEs (HSAEs; Levels 3-5) and non-diagnostic biopsy samples.

RESULTS

A total of 2,665 EMB cases were performed in 744 pediatric heart transplant recipients (median age, 12 years [interquartile range, 4.8, 16.7]; 54% male). AEs occurred in 88 cases (3.3%), of which 28 (1.1%) were HSAEs. AEs attributable to EMB included tricuspid valve injury, transient complete heart block, and right bundle branch block. Amongst 822 cases involving coronary angiography, 10 (1.2%) resulted in a coronary-related AE. There were no myocardial perforations or deaths. Multivariable risk factors for HSAEs included fewer prior catheterizations (p = 0.006) and longer case length (p < 0.001). EMB yielded sufficient tissue for diagnosis in 99% of cases. Longer time since heart transplant was the most significant predictor of a non-diagnostic biopsy sample (p < 0.001).

CONCLUSIONS

In the current era, cardiac catheterizations involving EMB can be performed in pediatric heart transplant recipients with a low AE rate and high diagnostic yield. Risk of HSAEs is increased in early post-transplant biopsies and with longer case length. Longer time since heart transplant is associated with non-diagnostic EMB samples.

Universal noninvasive detection of solid organ transplant rejection

It is challenging to monitor the health of transplanted organs, particularly with respect to rejection by the host immune system. Because transplanted organs have genomes that are distinct from the recipient's genome, we used high throughput shotgun sequencing to develop a universal noninvasive approach to monitoring organ health. We analyzed cell-free DNA circulating in the blood of heart transplant recipients and observed significantly increased levels of cell-free DNA from the donor genome at times when an endomyocardial biopsy independently established the presence of acute cellular rejection in these heart transplant recipients. Our results demonstrate that cell-free DNA can be used to detect an organ-specific signature that correlates with rejection, and this measurement can be made on any combination of donor and recipient. This noninvasive test holds promise for replacing the endomyocardial biopsy in heart transplant recipients and may be applicable to other solid organ transplants.

Gene-expression profiling for rejection surveillance after cardiac transplantation

BACKGROUND

Endomyocardial biopsy is the standard method of monitoring for rejection in recipients of a cardiac transplant. However, this procedure is uncomfortable, and there are risks associated with it. Gene-expression profiling of peripheral-blood specimens has been shown to correlate with the results of an endomyocardial biopsy.

METHODS

We randomly assigned 602 patients who had undergone cardiac transplantation 6 months to 5 years previously to be monitored for rejection with the use of gene-expression profiling or with the use of routine endomyocardial biopsies, in addition to clinical and echocardiographic assessment of graft function. We performed a noninferiority comparison of the two approaches with respect to the composite primary outcome of rejection with hemodynamic compromise, graft dysfunction due to other causes, death, or retransplantation.

RESULTS

During a median follow-up period of 19 months, patients who were monitored with gene-expression profiling and those who underwent routine biopsies had similar 2-year cumulative rates of the composite primary outcome (14.5% and 15.3%, respectively; hazard ratio with gene-expression profiling, 1.04; 95% confidence interval, 0.67 to 1.68). The 2-year rates of death from any cause were also similar in the two groups (6.3% and 5.5%, respectively; P=0.82). Patients who were monitored with the use of gene-expression profiling underwent fewer biopsies per person-year of follow-up than did patients who were monitored with the use of endomyocardial biopsies (0.5 vs. 3.0, P<0.001).

CONCLUSIONS

Among selected patients who had received a cardiac transplant more than 6 months previously and who were at a low risk for rejection, a strategy of monitoring for rejection that involved gene-expression profiling, as compared with routine biopsies, was not associated with an increased risk of serious adverse outcomes and resulted in the performance of significantly fewer biopsies. (ClinicalTrials.gov number, NCT00351559.)

Tricuspid regurgitation after orthotopic heart transplantation

BACKGROUND

Tricuspid regurgitation (TR) is a relatively common abnormality in normal adults as well as after orthotopic heart transplantation (OHT). A few studies have shown reduction in the incidence of TR after OHT by total bicaval surgical anastomosis technique. Other studies reported no significant difference in the rates of TR between the standard and bicaval techniques.

OBJECTIVE

Evaluate and compare the degree of TR after OHT by standard and bicaval anastomosis techniques.

METHOD

Echocardiograms from the first 56 consecutive patients that had the total bicaval surgical technique performed were retrospectively reviewed and compared with the last 57 consecutive patients who had the standard biatrial technique performed. Patients with adequate two-dimensional and Doppler echocardiograms were included.

RESULTS

No statistical difference was observed for each grade of TR at both early and late time points. No significant difference was observed between the TR velocities of both biatrial and bicaval anastomosis patients at different periods.

CONCLUSION

There appears to be no difference between the TR severity and TR velocity at early and late time points regardless of anastomotic technique.

Limited utility of endomyocardial biopsy in the first year after heart transplantation

BACKGROUND

Surveillance endomyocardial biopsies (EMBs) are used for the early diagnosis of acute cardiac allograft rejection. Protocols became standardized in an earlier era and their utility with contemporary immunosuppression has not been investigated.

METHODS

We studied 258 patients after orthotopic heart transplantation comparing 135 patients immunosuppressed by mycophenolate mofetil (MMF) with 123 patients treated by azathioprine (AZA); both with cyclosporine and corticosteroids after induction therapy with rabbit antithymocyte globulin. Fifteen EMBs were scheduled in the first year. Additional EMBs were performed for suspected rejection, after treatment, or for inadequate samples. The MMF group had 1875 EMBs vs. 1854 in the AZA group.

RESULTS

The yield of International Society for Heart and Lung Transplantation (ISHLT) grade> or =3A biopsy-proven acute rejection (BPAR) was 1.87% per biopsy (35 of 1875) with MMF vs. 3.13% (58 of 1854) with AZA P=0.024. The number of clinically silent BPAR ISHLT grade > or =3A (the true yield of surveillance EMBs) was 1.39% (26 of 1875) of biopsies MMF vs. 2.1% (39 of 1854) AZA, P=0.48. There were five serious complications requiring intervention or causing long-term sequelae; 0.13% (5 of 3729) per biopsy and 1.94% (5 of 258) per patient. The incidence of all definite and potential complications was 1.42% (53 of 3729) per biopsy and 20.5% (53 of 258) per patient. There was no biopsy-related mortality.

CONCLUSION

The yield of BPAR was low in the AZA group and very low in the MMF group. The incidence of complications was also low, but repeated biopsies led to a higher rate per patient. Routine surveillance EMBs and the frequency of such biopsies should be reevaluated in the light of their low yield with current immunosuppression.

Prevalence and risk factors for tricuspid valve regurgitation after pediatric heart transplantation

BACKGROUND

Risk factors for tricuspid regurgitation (TR) after adult orthotopic heart transplantation (OHT) have been reported, although there are no pediatric data.

METHODS

This study was a single-center retrospective analysis of patients <or= 18 years of age who underwent OHT from January 1990 to December 2004. The impact of TR was evaluated with respect to outcomes (graft failure, etc.).

RESULTS

Echocardiograms were available for 99 patients (105 grafts with 6 re-transplants) at a median age of 4.5 years (range 18 days to 17.1 years): 51 (49%) were male; 46 (44%) were transplanted for congenital heart disease; and 76 (72%) had a biatrial anastomosis. Significant TR developed in 30 grafts (29.5%) within a median duration after OHT of 1.2 years (range 0 day to 8.2 years); persistent significant TR until last follow-up was present in 21 grafts (20%). Graft failure (death or need for retransplantation) occurred in 41 grafts (39%), including 14 of 21 grafts (67%) with significant TR. By Kaplan-Meier analysis, freedom from significant TR (95% confidence interval [CI]) at 1, 5 and 10 years was 91.0% (83.4% to 95.2%), 70.2% (55.4% to 80.9%) and 61.5% (39.2% to 77.6%), respectively. No risk factors were identified. Development of significant TR was highly associated with graft failure (p = 0.005).

CONCLUSIONS

Significant TR occurs with comparable frequency in pediatric and adult OHT populations; risk factors identified in adults were not present in our pediatric population. Development of significant TR in pediatric heart transplant recipients is highly associated with graft failure.

Molecular Testing for Long-term Rejection Surveillance in Heart Transplant Recipients: Design of the Invasive Monitoring Attenuation Through Gene Expression (IMAGE) Trial

BACKGROUND

Acute rejection continues to occur beyond the first year after cardiac transplantation, but the optimal strategy for detecting rejection during this late period is still controversial. Gene expression profiling (GEP), with its high negative predictive value for acute cellular rejection (ACR), appears to be well suited to identify low-risk patients who can be safely managed without routine invasive endomyocardial biopsy (EMB).

METHODS

The Invasive Monitoring Attenuation Through Gene Expression (IMAGE) study is a prospective, multicenter, non-blinded, randomized clinical trial designed to test the hypothesis that a primarily non-invasive rejection surveillance strategy utilizing GEP testing is not inferior to an invasive EMB-based strategy with respect to cardiac allograft dysfunction, rejection with hemodynamic compromise (HDC) and all-cause mortality.

RESULTS

A total of 199 heart transplant recipients in their second through fifth post-transplant years have been enrolled in the IMAGE study since January 13, 2005. The study is expected to continue through 2008.

CONCLUSIONS

The IMAGE study is the first randomized, controlled comparison of two rejection surveillance strategies measuring outcomes in heart transplant recipients who are beyond their first year post-transplant. The move away from routine histologic evaluation for allograft rejection represents an important paradigm shift in cardiac transplantation, and the results of this study have important implications for the future management of heart transplant patients.

Clinical utilities of peripheral blood gene expression profiling in the management of cardiac transplant patients

Cardiac allografts induce host immune responses that lead to endomyocardial tissue injury and progressive graft dysfunction. Inflammatory cell infiltration and myocyte damage characterize acute cellular rejection (ACR) that presents episodically in either a subclinical or symptom-associated manner. Sampling of the endomyocardium by transvenous biopsy enables pathologic grading using light microscopic criteria to distinguish severity based on the focality or diffuseness of inflammation and associated myocyte injury. Monitoring for ACR utilizes endomyocardial biopsy in conjunction with history and physical examination and assessment of allograft function by echocardiography. However, procedural and interpretive issues limit the diagnostic certainty provided by endomyocardial biopsy. The dynamic profiling of genes expressed by peripheral blood mononuclear cells (PBMCs) enables quantitative assessments of intracellular mRNA whose levels fluctuate during systemic alloimmune responses. Gene expression profiling of PBMCs using a multi-gene ACR classifier enables the AlloMap molecular expression test to distinguish moderate to severe ACR (p = 0.0018) in heart transplant patients. The AlloMap test provides molecular insights into a patient's risk for ACR by distilling the aggregate expression levels of its informative genes into a single score on a scale of 0 to 40. The selection of a score as a threshold value for clinical decision-making is based on its associated negative predictive value (NPV), which ranges from 98 to 99% for values in three post-transplant periods: > 2 to < or =6 months, > 6 to < or = 12 months, and > 12 months. Scores below the threshold value rule out ACR, while those above suggest increased ACR risk. Incorporating the AlloMap test into immunomonitoring protocols provides an opportunity for clinicians to enhance patient care and to define its role in immunodiagnostic strategies to optimize the clinical outcomes of heart transplant recipients. This summary highlights the concepts presented in an invited presentation at a conference focused on Immunodiagnostics and Immunomonitoring: From Research to Clinic, in San Diego, CA on November 7, 2006.

Echocardiography in the cardiac transplant recipient

Despite the widespread use of echocardiography in the cardiac allograft recipient, the clinical usefulness of this practice is not well defined. In this article, the authors review the spectrum of echocardiographic findings in the adult heart transplant patient. Appreciation of typical alterations from "normal" allows the transplant physician to identify clinically significant changes and to avoid unnecessary invasive procedures based on misinterpretation of these differences. Though abnormalities of systolic and diastolic function correlate with episodes of acute rejection, the primary diagnostic usefulness of echocardiography in acute rejection is guiding the endomyocardial biopsy. Additionally, echocardiography has found a role as a supplement to invasive angiography in the diagnosis of cardiac allograft vasculopathy.

Endomyocardial biopsy-related tricuspid regurgitation after orthotopic heart transplantation: single-center experience

BACKGROUND

Damage of tricuspid valve (TV) with resultant tricuspid regurgitation (TR) induced by endomyocardial biopsy (EMB) following heart transplantation has been reported in several studies. This study tried to determine the prevalence of EMB-related iatrogenic damage over tricuspid apparatus following orthotopic heart transplantation and to evaluate its impact on the patients.

METHODS

Fifty patients received orthotopic heart transplantation between July 1987 and March 2005. Eleven patients were excluded from the study due to early postoperative mortality or inadequate follow-up. The medical records of the remaining 39 patients were reviewed retrospectively for basic characteristics as well as each attempted EMB. The iatrogenic damage of tricuspid apparatus and serial change of TR were accessed with 2-D and Doppler echocardiography. The obtained data were analyzed for their statistical significance with SPSS (version 12.0).

RESULTS

A total of 373 biopsies were performed on the 39 patients between 1987 and 2005. The follow-up duration was 42.9+/-26.7 months. The prevalence of TR immediately following heart transplantation was 84.6%, with only 25.6% of patients having moderate or severe TR. At the end of the follow-up, the prevalence of TR increased to 92.3% and 61.5% of patients having moderate or severe TR, respectively. Eight patients (20.5%) had small chordae rupture (SCR) noted after 6.6+/-3.2 biopsies, and 10 patients (25.6%) had flail tricuspid valve (FTV) after 5.7+/-5.1 biopsies. Of patients with SCR, 62.5% had progression of TR, and 70% of patients with FTV showed significant TR change.

CONCLUSION

The prevalence of iatrogenic tricuspid apparatus damage was high in this study. It contributed to the progression of TR significantly regardless of the damage severity. Measurements should be taken for prevention of iatrogenic tricuspid apparatus damage induced by EMB.

Cardiac Surgery after Heart Transplantation: Coronary Artery Bypass Grafting and Heart Valve Replacement

INTRODUCTION

Due to increasing need for and a shortage of donor organs, therapeutic procedures such as heart valve replacement for valve insufficiency and coronary artery bypass grafting (CABG) for graft vasculopathy (GVP) must be performed to improve allograft function to avoid retransplantation.

METHODS

We performed a retrospective analysis of patients who underwent surgical procedures after orthotopic heart transplantation. Since 1989, we have performed more than 1400 heart transplantation procedures. Valve replacement was necessary in 8 patients and CABG was necessary in 3 patients. Five patients received valve prostheses (3 bioprostheses and 2 mechanical valves) at the tricuspid position. Three patients received a Hancock bioprosthesis at the mitral position. One of the 3 received the valve 3 years after heart transplantation while suffering from mitral regurgitation grade IV, and another patient received the valve 1 year following heart transplantation while suffering from mitral insufficiency grade III due to infective endocarditis. Three patients underwent coronary artery revascularization, 2 patients underwent the procedure 1 and 7 years after heart transplantation because of GVP, 1 patient underwent the procedure simultaneously with heart transplantation because of donor coronary artery disease. One patient received concomitant CABG with heart transplantation because of 75% left anterior descending stenoses in the donor organ, and one patient received CABG 1 year after heart transplantation because of rapidly progressive GVP in the left anterior descending artery. The third patient had 3-vessel disease with 95% left stem and 75% ramus circumflex, ramus marginalis, and ramus diagonalis.

RESULTS

Two patients who underwent CABG and 4 patients who underwent valve replacement are still alive and maintain good clinical performance. One patient with a graft at the mitral position died 9 years after heart transplantation and 6 years after mitral valve replacement. Two patients with a graft at the tricuspid position died 17 and 4 years after heart transplantation (6 and 3 years after valve replacement, respectively). One patient with a bioprostheses at the tricuspid position had to be retransplanted 2 years following valve replacement while suffering from a paravalvular leakage grade III.

CONCLUSION

Cardiac surgical procedures can be safely performed after heart transplantation. To improve graft and patient survival, such procedures must be carefully performed after heart transplantation to avoid retransplantation. The shortage of donor organs will and must lead to an increase in the number of conventional procedures performed to improve allograft function in transplanted hearts.

Tricuspid valve replacement after cardiac transplantation

PURPOSE OF REVIEW

Tricuspid valve regurgitation is the most frequent valvular complication following orthotopic cardiac transplantation. It leads to diminished quality of life and predicts shortened long-term survival. The optimal surgical management of refractory tricuspid valve regurgitation in this setting is unclear.

RECENT FINDINGS

Tricuspid valve regurgitation following cardiac transplantation is likely related to accumulated injury from repeated endomyocardial biopsies. Durability of repair in this setting was shown to be suboptimal. Replacement with a bioprosthesis was found to be durable and relieves symptoms of heart failure associated with tricuspid valve regurgitation in the majority of patients. Prophylactic tricuspid valve annuloplasty at transplantation was found to significantly decrease the incidence of early and late tricuspid valve regurgitation; long-term benefits remain unclear.

SUMMARY

Results of tricuspid valve repair in the post-cardiac transplant setting are not ideal, and this strategy is better suited to treating functional tricuspid valve regurgitation resulting from annular dilatation. Tricuspid valve replacement with a bioprosthesis is a safe, durable, and effective method of treating tricuspid valve regurgitation following transplantation and allows for future endomyocardial biopsies to be performed. Mechanical valves should be avoided. A randomized controlled trial examining the long-term outcomes of prophylactic tricuspid annuloplasty is warranted.

Donor Tricuspid Annuloplasty During Orthotopic Heart Transplantation: Long-Term Results of a Prospective Controlled Study

BACKGROUND

Development of tricuspid regurgitation after orthotopic heart transplantation can cause heart failure along with renal and hepatic impairment and portends a poor prognosis. If tricuspid regurgitation causes significant symptoms, tricuspid valve repair or replacement is often required. This study was designed to study the effects of prophylactic tricuspid valve annuloplasty (TVA) during orthotopic heart transplantation on long-term survival, renal function, and amount of tricuspid regurgitation.

METHODS

Between April 1997 and March 1998, 60 patients (aged 18 to 70 years; 22 female) randomly received either standard bicaval orthotopic heart transplantation (group STD; n = 30) or bicaval orthotopic heart transplantation with DeVega TVA (group TVA; n = 30). Tricuspid valve annuloplasty was performed on the donor heart before implantation using pledgeted 2-0 polypropylene and sized to an annulus of 29 mm. Echocardiographic measurements, laboratory values, and hemodynamics were obtained prospectively and reviewed by an independent data analyst.

RESULTS

Follow-up of patients as of December 2003 was complete. Although there was a perioperative mortality advantage in group TVA, there was no difference between groups in long-term survival. At the end of the study, however, there was a statistical difference (group STD versus group TVA, p < 0.05) with regard to cardiac mortality (7 of 30 versus 3 of 30), average amount of tricuspid regurgitation (1.5 +/- 1.3 versus 0.5 +/- 0.4), percentage of patients with 2+ or greater tricuspid regurgitation (34% versus 0%), serum creatinine (2.9 +/- 2.0 versus 1.8 +/- 0.7), and difference in serum creatinine over baseline (2.0 +/- 2.1 versus 0.7 +/- 0.8).

CONCLUSIONS

Prophylactic DeVega TVA of the donor heart is durable and decreases the incidence of cardiac-related mortality and tricuspid regurgitation after orthotopic heart transplantation. In addition, there is improved protection of renal function. Considering the ease and safety of TVA and its advantages, it should be performed as a routine adjunct to orthotopic heart transplantation.

Tricuspid valve chordal tissue in endomyocardial biopsy specimens of patients with significant tricuspid regurgitation

OBJECTIVES

Tricuspid regurgitation is the most common valvular abnormality after orthotopic heart transplantation, with multiple etiologic factors implicated. The purpose of this study was to determine if the endomyocardial biopsy specimens of patients who developed significant tricuspid valve regurgitation (TVR) after cardiac transplantation had evidence of chordal tissue.

METHODS

The echocardiograms of 98 patients who had cardiac transplantation between 1986 and 2002 were reviewed for evidence of significant TVR greater than mild. The biopsy specimens of all patients with significant TVR were then reviewed for histologic evidence of tricuspid chordal tissue and frequency and severity of rejection episodes. Clinical information collected included the presence of any systolic murmurs, significant dyspnea, and invasive hemodynamic measurements.

RESULTS

The incidence of significant TVR was 19% (n = 19 patients). Histologic evidence of chordal tissue was present in 9 patients (47%) with significant TVR. Patients whose biopsy specimens evidenced chordal tissue tended to have a greater degree of TVR, but this was not statistically significant (odds ratio, 2.07; 95% confidence interval, 0.537-8.01, p = 0.32). There was no statistically significant difference in the number of biopsy specimens (p = 0.798), the number of rejection episodes (p = 0.73), or overall left or right ventricular systolic function between the patients with and without biopsy specimen evidence of chordal tissue disruption. Most of the patients with evidence of significant TVR after chordal tissue biopsy were clinically asymptomatic, with no significant change in their hemodynamics.

CONCLUSION

Histologic evidence of chordal tissue in endomyocardial biopsy specimens was present in 47% of patients with significant TVR and did not relate to the number of biopsy procedures performed or the frequency of rejection episodes. This study provides histologic evidence that chordal tissue damage can occur after cardiac biopsy, resulting in significant TVR; however, it is clinically well tolerated by affected patients.

Endomyocardial biopsy - jugular/subclavian vein approach

Endomyocardial biopsy (EMB) is a diagnostic procedure mainly to survey the sufficiency of immunosuppressive therapy after cardiac transplantation. Other indications for EMB remain controversial. After insertion of an introducer sheet in Seldinger's technique, four to six biopsies are taken from the right ventricle by fluoroscopic guidance. EMB is a very safe operation with a low complication rate which can be rapidly performed with little inconvenience for the patient if performed by a skilled surgeon.

Early Experience with Real-Time Three-Dimensional Echocardiographic Guidance of Right Ventricular Biopsy in Children

BACKGROUND

Right ventricular endomyocardial biopsy is the gold standard for detecting active myocardial inflammation in cardiomyopathy as well as rejection after cardiac transplantation. This procedure has historically required the exclusive use of fluoroscopic guidance to guide catheter, sheath, and bioptome manipulation. The current study evaluates the feasibility and utility of real-time transthoracic three-dimensional echocardiography (3DE) to guide right ventricular endomyocardial biopsies in children.

METHODS

From July 2003 to April 2004, we utilized real-time 3DE in 28 consecutive cardiac catheterizations in children aged 18 months to 16 years who were undergoing endomyocardial biopsy. A commercially available 3DE scanner (Philips Sonos 7500) equipped with a 2-4 MHz 3D matrix array transthoracic probe was utilized in all cases.

RESULTS

A total of 123 endomyocardial biopsy samples were obtained in nine patients (BSA 0.85 m(2)+/- 0.33 m(2)). Of these 123 samples, 99 (80%) were obtained with the use of real-time transthoracic 3DE. There were no complications, including no new tricuspid valve leaflet flail or pericardial effusion. 3DE proved to be a reliable noninvasive modality to properly direct the bioptome to the desired site of biopsy within the right ventricle. As familiarity with this technique increased, the need for fluoroscopic guidance of bioptome manipulation in the right ventricle was minimized.

CONCLUSIONS

The use of real-time transthoracic 3DE in endomyocardial right ventricular biopsies in children is both feasible and safe. Further study to determine the impact of real-time 3DE guidance on fluoroscopy and case times for endomyocardial biopsies is warranted.

Tricuspid Regurgitation After Cardiac Transplantation: How Many Biopsies Are Too Many?

BACKGROUND

Tricuspid regurgitation (TR) is common in patients after orthotopic cardiac transplantation (OHT). Endomyocardial biopsy (EMB) used to monitor for rejection may be a cause of TR. The purpose of this study was to identify a correlation between the severity of TR and the number of EMBs.

METHODS

We studied 101 patients with OHT at our institution between May 1987 and August 2001. The number of EMBs performed in each patient was determined. Data on technique of anastomosis, liver and renal function, ejection fraction, and pulmonary artery pressure were also extracted. Echocardiography reports were reviewed to determine the presence and severity of TR. Symptoms of right heart failure were assessed by the amount of diuretic intake.

RESULTS

Twenty-five (25%) of 101 patients had evidence of severe TR, whereas 76 (75%) had non-severe TR. Multivariate analysis identified EMB as the only independent predictor of the severity of TR (p < 0.0001). At last follow-up, 60% of patients with more than 31 EMBs had developed severe TR, whereas none of the patients with less than 18 EMBs had severe TR. Of the 25 patients who had severe TR, 15 (61%) needed high doses of daily diuretics, and 4 (16%) required tricuspid valve replacement.

CONCLUSIONS

The development of TR after OHT is in large part due to EMBs used to monitor for rejection. There is a direct correlation between the number of EMBs and the severity of TR. We suggest a cutoff of less than 31 EMBs to reduce the risk of severe TR.