Morbidity of endomyocardial biopsy in cardiac transplant recipients

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

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.

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.

Liquid biopsy for minimally invasive heart transplant monitoring: a pilot study

BACKGROUND

Heart transplantation allows for a long-term management of patients with end-stage heart failure. After the surgery, organ rejection is monitored with endomyocardial biopsy, which is an invasive, but not always informative procedure. Therefore, there is a pressing need for a new, safe, yet reliable, diagnostic method. Here, we present a pilot study confronting liquid biopsy based on donor-specific cell-free DNA with the protocol endomyocardial biopsy.

METHODS

The study was performed on 21 blood samples matched with endomyocardial biopsy (graded according to acute cellular rejection scale) from nine patients after heart transplantation. Genotyping was performed on genomic DNA from donors and recipients for 10 single-nucleotide polymorphisms (SNPs). Cell-free DNA isolated from plasma was analysed with digital droplet PCR to detect donor-specific alleles.

RESULTS

From 21 analysed endomyocardial biopsies, 4 were graded as 0R and 17 as 1R. Liquid biopsy was successfully performed in each sample for all informative SNPs (median of 3 per patient). We observed a high homogeneity of the results between SNPs in each sample (interclass correlation coefficient of >0.9).

CONCLUSIONS

There is a undeniable need for an alternative, non-invasive diagnostic procedure of early transplant rejection and investigation of donor-derived cell-free DNA seems to be the promising choice. The very high sensitivity is particularly enticing to consider liquid biopsy as a potential screening tool. Its minimal invasiveness may allow for more frequent examination and, thus, tighter monitoring. The reliable assessment of its clinical utility requires an adequately powered and properly designed multicentre study.

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.

Outcomes of low-intensity biopsy surveillance for rejection in paediatric cardiac transplantation

BACKGROUND

Significant inter-centre variability in the intensity of endomyocardial biopsy surveillance for rejection following paediatric cardiac transplantation has been reported. Our aim was to determine if low-intensity biopsy surveillance with two scheduled biopsies in the first year would produce outcomes similar to published registry outcomes.

METHODS

A retrospective study of paediatric recipients transplanted between 2008 and 2014 using a low-intensity biopsy protocol consisting of two surveillance biopsies at 3 and 12-13 months in the first post-transplant year, then annually thereafter. Additional biopsies were performed based on echocardiographic and clinical surveillance. Excluded were recipients that were re-transplanted or multi-organ transplanted or were followed at another institution.

RESULTS

A total of 81 recipients in the first 13 months after transplant underwent an average of 2 (SD ± 1.3) biopsies, 24 ± 6.8 echocardiograms, and 17 ± 4.4 clinic visits per recipient. During the 13-month period, 19 recipients had 24 treated rejection episodes, with the first at an average of 2.8 months post-transplant. The 3-, 12-, 36-, and 60-month conditional on discharge graft survival were 100%, 98.8%, 98.8%, and 90.4%, respectively, comparable to reported figures in major paediatric registries. At a mean follow-up of 4.7 ± 2.1 years, four patients (4.9%) developed cardiac allograft vasculopathy, three (3.7%) developed a malignancy, and seven (8.6%) suffered graft loss.

CONCLUSION

Rejection surveillance with a low-intensity biopsy protocol demonstrated similar intermediate-term outcomes and safety measures as international registries up to 5 years post-transplant.

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.

Current status of endomyocardial biopsy

Endomyocardial biopsy (EMB) is widely used for surveillance of cardiac allograft rejection and for the diagnosis of unexplained ventricular dysfunction. Typically, EMB is performed through the jugular or femoral veins and is associated with a serious acute complication rate of less than 1% using current flexible bioptomes. Although it is accepted that EMB should be used to monitor for rejection after transplant, use of EMB for the diagnosis of various myocardial diseases is controversial. Diagnosis of myocardial disease in the nontransplant recipient is often successful via noninvasive investigations including laboratory evaluation; echocardiography, nuclear studies, and magnetic resonance imaging can yield specific diagnoses in the absence of invasive EMB. Therefore, use of the technique is patient specific and depends on the potential prognostic and treatment information gained by establishing a pathologic diagnosis beyond noninvasive testing.

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.)

Clozapine-induced cardiotoxicity: a clinical update

Clozapine is a valuable drug for patients with treatment-resistant schizophrenia. Myocarditis is the most publicised cardiac complication of clozapine treatment, but cardiomyopathy and pericarditis have also been reported. Myocarditis has heterogeneous and non-specific presenting features, making it difficult to identify patients with clozapine-related myocarditis clinically. A high index of suspicion is required. The gold standard for diagnosis of myocarditis is an endomyocardial biopsy, but this is not a practical initial approach. Transthoracic echocardiography is a valuable, reproducible and widely available tool to assist in diagnosis of clozapine-induced cardiotoxicity. The level of B-type natriuretic peptide, a hormone secreted in response to ventricular wall stress, may be useful for evaluating patients with clozapine-induced cardiac dysfunction and may in the future be useful for screening asymptomatic patients. The mainstay of treatment of clozapine-induced cardiotoxicity is cessation of clozapine and provision of supportive care.

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.

Our Experience in Cardiac Transplantation in Baskent University

Recently cardiac transplantation has an important place in treatment of end-stage cardiac failure. In Turkey between 2003 and 2005 at 10 centers 64 cardiac transplantations were performed including five at our facility. Herein we have presented our results. All patients were men of mean age 34.2 +/- 10.7 (17 to 44) years. Upon preoperative echocardiography their mean ejection fraction was 18% +/- 3.27% (17% to 23%). Pulmonary vascular resistance was 4.47 wood unit in one patient and in one case, there was Rh incompatibility between donor and recipient. We used HTK solution for protection of donor hearts. Mean ischemia time was 251.2 +/- 62.7 minutes (155 to 314). Mean aortic clamping time was 84 +/- 4.7 minutes (80 to 90). In all patients we performed a biatrial anastomosis technique. Hemofiltration was used to prevent hemodilution during operation. In the postoperative period four patients had acute renal dysfunction; one, a minor cerebrovascular accident; two, reoperated because of bleeding; one, cholestasis; one, temporary atrio-ventricular block; and one, mediastinitis. Mean follow-up time was 15.6 +/- 19.7 months (2 to 50). Neither early nor late mortality has occurred. All patients are in New York Heart Association class I. In all cases we used triple immunosuppressive therapy. In the follow-up period the mean number of cardiac biopsies per patient was 4.2 +/- 3.03 (2 to 8). Two cases had cardiac catheterization. As a complication of cardiac biopsy, pericardial tamponade developed in one patient; in another one we observed a right ventricular aneursym after cardiac biopsy. Cardiac transplantation was performed with low mortality and morbidity rates in end-stage cardiac failure patients with longer life expectancy and higher life quality. Unfortunately in our country, because of difficulties to find donor hearts, cardiac transplantations were small in number. For better results, we need a larger series.

The economic implications of noninvasive molecular testing for cardiac allograft rejection

Endomyocardial biopsy is the mainstay for monitoring cardiac allograft rejection. A noninvasive strategy--peripheral blood gene expression profiling of circulating leukocytes--is an alternative with proven benefits, but unclear economic implications. Financial data were obtained from five cardiac transplant centers. An economic evaluation was conducted to compare the costs of outpatient biopsy with those of a noninvasive approach to monitoring cardiac allograft rejection. Hospital outpatient biopsy costs averaged 3297 US dollars, excluding reimbursement for professional fees. Costs to Medicare and private payers averaged 3581 US dollars and 4140 US dollars, respectively. A noninvasive monitoring test can reduce biopsy utilization. The savings to health care payers in the United States can be conservatively estimated at approximately 12.0 million US dollars annually. Molecular testing using gene expression profiling of peripheral circulating leukocytes is a new technology that offers physicians a noninvasive, less expensive alternative to endomyocardial biopsy for monitoring allograft rejection in cardiac transplant patients.

Routine surveillance endomyocardial biopsy continues to detect significant rejection late after heart transplantation

BACKGROUND

The need for continued surveillance endomyocardial biopsies beyond the first year after cardiac transplantation is controversial. We evaluated the incidence of rejections requiring treatment (International Society Heart and Lung Transplantation grade 3A or greater) in patients 5 years or more after heart transplantation.

METHODS

We conducted a retrospective chart review of all patients who underwent at least 1 endomyocardial biopsy at our center 5 years or more after heart transplantation.

RESULTS

A total of 461 biopsies were performed in 77 patients 5 or more years after heart transplantation. Nine episodes of grade 3A or greater rejection were identified in 8 of 77 patients (10%). During the first year, 7.6% of biopsies were grade 3A or greater. Grade 3A rejection occurred in approximately 3.5% to 4% of biopsies during years 2 to 7. The overall incidence of procedural related complications at our institution was < 0.5%.

CONCLUSION

Endomyocardial biopsies continue to detect clinically significant rejection beyond 5 years after cardiac transplantation. The overall incidence of procedural related complications requiring treatment was low and none was life threatening. The absence of early rejection does not predict freedom from late rejection. Therefore, we continue to recommend surveillance biopsies in cardiac transplant recipients late after transplantation.

Complications of endomyocardial biopsy in children

OBJECTIVES

To evaluate the incidence of, and risk factors for, complications of endomyocardial biopsy in children.

BACKGROUND

Endomyocardial biopsy (EMB) is a low risk procedure in adults, but there is a paucity of data with regard to performing this procedure in children.

METHODS

Retrospective review of the morbidity and mortality of 1,000 consecutive EMB procedures.

RESULTS

One thousand EMB procedures (right ventricle 986, left ventricle 14) were performed on 194 patients from July 1987 through March 1996. Indications for EMB included heart transplant rejection surveillance (846) and the evaluation of cardiomyopathy or arrhythmia for possible myocarditis (154). Thirty-seven (4%) procedures were performed on patients receiving intravenous inotropic support. There was one biopsy related death, secondary to cardiac perforation, in a two-week-old infant with dilated cardiomyopathy. There were nine perforations of the right ventricle, eight occurring in patients with dilated cardiomyopathy and one in a transplant recipient. The transplant patient did not require immediate intervention; two patients required pericardiocentesis alone, and six underwent pericardiocentesis and surgical intervention. All nine perforations were from the femoral venous approach (p < 0.01). Multivariate analysis demonstrated that the greatest risk of perforation occurred in children being evaluated for possible myocarditis (p = 0.01) and in those requiring inotropic support (p < 0.01). Other complications included arrhythmia (5) and single cases of coronary-cardiac fistula, flail tricuspid leaflet, pneumothorax, hemothorax, endocardial stripping and seizure.

CONCLUSIONS

Risk of endomyocardial biopsy is highest in sick children with suspected myocarditis on inotropic support. However, EMB can be performed safely with very low morbidity in pediatric heart transplant recipients.

Routine surveillance endomyocardial biopsy: late rejection after heart transplantation

BACKGROUND

Transplant programs use routine surveillance endomyocardial biopsies (RSEMB), which are performed at preset intervals to diagnose cardiac rejection. This retrospective study determined the incidence of graft rejection detected by RSEMB.

METHODS

The records of 95 patients who underwent heart transplantation between 1987 and 1995 were reviewed. Rejection incidence was recorded for 80 patients who survived at least 30 days, with a mean follow-up of 35 months.

RESULTS

One thousand five hundred sixteen total biopsies were performed; 1,170 were RSEMB. Four hundred seventy-five total rejection episodes occurred and 269 (56%) were diagnosed by RSEMB. Two distinct patient groups were identified. The majority (70 patients), had a decline in the incidence of rejection and no rejection episodes were identified by RSEMB after 36 months. In contrast, the high rejection group (10 patients) had a significantly higher ongoing rejection rate (p < or = 0.04 to p < or = 0.001) throughout their postoperative course up to 72 months.

CONCLUSIONS

The majority of our transplant patients demonstrate a decrease in rejection with time and do not require RSEMB beyond 30 months. We identified a group of patients who exhibited a higher rate of rejection and need continued RSEMB.

Are surveillance endomyocardial biopsies necessary during OKT3 induction therapy?

BACKGROUND

To determine the utility of surveillance endomyocardial biopsies (EMBs) during a 14-day OKT3 induction course after cardiac transplantation, histologic results of the first two EMBs were retrospectively reviewed.

METHODS

Seventy-three consecutive cardiac transplant recipients who received an OKT3-based quadruple sequential immunosuppressive protocol were analyzed. Patients were predominantly white (85%) and male (72%), with ischemic cardiomyopathy (54%) and a pretransplant panel-reactive antibody level of <10% (93%).

RESULTS

The first EMB in 73 patients demonstrated no rejection in 70 patients (96%) and grade 1A rejection in 3 patients (4%). The second EMB showed no rejection in 64 patients (88%), grade 1A or 1B rejection in 8 patients (11%), and grade 3A rejection without hemodynamic compromise in only 1 patient (1%). Absolute CD3+ cells remained below 25 lymphocytes/mm3, and mean trough OKT3 serum levels exceeded 500 ng/ml throughout the 14 days of therapy, demonstrating the immunosuppressive efficacy of OKT3. Posttransplant echocardiograms showed normal left ventricular systolic function.

CONCLUSIONS

Since 145 of 146 EMBs (99%) demonstrated no or minimal allograft rejection, a large cost savings could be realized if EMBs were performed only when clinically indicated during the 14-day OKT3 induction course in cardiac transplant recipients. Appropriate immunologic monitoring and echocardiographic testing may obviate the need for performing costly EMBs during OKT3 induction without an adverse clinical outcome.

Alternative approaches to right ventricular endomyocardial biopsy

Cardiologists are performing endomyocardial biopsy procedures with increasing frequency, particularly in patients who have undergone cardiac transplantation. Because of the necessity for performing multiple biopsies in many of these patients and the subsequent complications that may arise, we have developed a simple and efficient technique for obtaining endomyocardial biopsy samples. As an alternative to retrieving biopsy samples by the conventional right internal jugular or femoral venous approach, we use the right or left internal jugular or subclavian approach. The procedure utilizes a 7 Fr 35 cm sheath and dilator system placed into the right ventricle over a balloon-tipped catheter. After the sheath is positioned via either the internal jugular or subclavian vein, multiple samples can be obtained with standard available bioptomes. The sheath may then be exchanged for a triple-lumen catheter if desired. This approach permits routine changing of the central venous access lines within the sterile confines of the catheterization laboratory, with minimal discomfort to patients. We believe that this method represents an important alternative to conventional biopsy techniques.