Real-life use of letermovir prophylaxis for cytomegalovirus in heart transplant recipients.

INTRODUCTION: Cytomegalovirus (CMV) remains the predominant opportunistic infection following solid organ transplantation (SOT). While valganciclovir is the drug of choice for CMV prophylaxis, its utility can be compromised due to the risk of cytopenia. Letermovir, a novel agent approved for CMV prophylaxis in allogeneic hematopoietic stem cell transplant recipients and high-risk kidney transplant recipients, exhibits reduced toxicity. This study aims to present the practical application of letermovir as both primary and secondary prophylaxis against CMV in heart transplant recipients (HTR). METHODS: In this observational, retrospective, single-center study, we included all consecutive adult HTRs from June 2020 to January 2022 who were administered letermovir for CMV prophylaxis. We documented instances of CMV breakthrough infections, side effects related to letermovir, changes in neutropenia following the switch from valganciclovir to letermovir, and any drug interactions with the immunosuppressive regimen. RESULTS: The study comprised 10 patients: two received primary prophylaxis with letermovir due to a high risk of CMV infection (donor-positive, recipient-negative serostatus), and eight received it as secondary prophylaxis following a CMV infection. The median duration of letermovir administration was 8 months (range 3-12 months). No CMV breakthrough infections were reported while on prophylaxis. However, three patients experienced CMV breakthrough infections after discontinuing letermovir prophylaxis (30%). No significant side effects were observed, although one patient reported digestive intolerance. Among the nine patients on tacrolimus, six needed reduced doses after switching to letermovir. CONCLUSION: This real-life study appears to support the effectiveness of letermovir prophylaxis in HTR. Nonetheless, the risk of CMV infection post-treatment cessation is notable. Further drug monitoring and research on the efficacy of letermovir for CMV prophylaxis in SOT patients is warranted.

Low acceptance rate of COVID-19 vaccination and reduced quality of life among heart transplant recipients during the COVID-19 pandemic.

OBJECTIVES: To investigate the impact of the current coronavirus disease 2019 (COVID-19) pandemic on the quality of life (QoL) and status of COVID-19 vaccination in heart transplant recipients (HTRs). METHODS: Patients who underwent allogeneic heart transplants between June 2006 and December 2019, who survived were selected from a follow-up registration form at our center. Data were collected using questionnaires in 2021, the QoL survey was conducted using the MOS 36-item Short-Form Health Survey (SF-36) and compared to the same time frame in 2019. The patients were divided into two groups: post-epidemic (A) and pre-epidemic (B) groups. We also recorded whether the participants had been vaccinated against COVID-19 (Beijing Sinovac COVID-19 vaccine). All the data obtained were analyzed. RESULTS: There were 88 patients who participated in the study. Only 12 (13.6%) were vaccinated. In terms of SF-36 scale assessments, after the outbreak of the COVID-19 pandemic, Group A scored lower in vitality [52.5(49.0, 58.0) vs. 75.0(69.0, 79.0), p < .001], social functioning [54.0(50.5, 58.0) vs. 74.0(67.5, 78.0), p < .001], role emotional [58.5(55.0, 62.0) vs. 67.0(63.0, 71.0), p < .001], and mental health [58.5(55.0, 62.0) vs. 76.0(72.0, 79.0), p < .001]. In Group A the mental component summary (MCS) significantly decreased [222.0(214.5, 230.0) vs. 289.0(277.5, 299.5), p < .001]. The PCS and MCS of HTRs who had been vaccinated against COVID-19 were significantly higher than those who had not [PCS: 283.5(280.0, 287.0) vs. 276.0(271.0, 279.0), p < .001; MCS: 245.0(141.5, 254.0) vs. 220.0(213.5, 226.5), p < .001]. CONCLUSION: Low acceptance levels of COVID-19 vaccination were observed in the HTRs. The QoL of the HTRs decreased after the COVID-19 pandemic.

Prevalence of iron deficiency in heart transplant recipients.

BACKGROUND: Optimal iron management is crucial to marginal patients such as heart transplant recipients. As inflammatory mechanisms are present in transplant recipients, the definition of iron deficiency used in the general population might not be appropriate. OBJECTIVE: To evaluate the prevalence and determinants of iron deficiency in Norwegian heart transplant recipients. METHODS: We consecutively assessed iron parameters in all Norwegian heart transplant recipients at their annual follow-up. Several definitions of iron deficiency suggested in the literature were assessed: ferritin <100 µg/L, or ferritin 100-300 µg/L combined with transferrin saturation of <20% (IDHF ); ferritin <100 µg/L (IDF100 ); transferrin saturation of <20% (IDTsat ), and ferritin <30 µg/L (IDF30 ). RESULTS: 179 of 378 heart transplant recipients (47%) had iron deficiency defined as IDHF . 152 patients (40%) had IDF100 , and 103 patients (27%) had IDTsat . 17 patients (5%) had IDF30 . 88 patients (23%) had a C-reactive protein (CRP) >5.0 µg/L. CONCLUSION: Iron deficiency defined as IDHF , IDF100, or IDTsat is prevalent in the heart transplant population, while IDF30 is not. Further research is required to identify the mechanisms of iron homeostasis in heart transplant recipients and to establish a definition of iron deficiency suitable for this population.

Trends in Kaposi's Sarcoma Morbidity: A Retrospective Cohort Study of Heart and Lung Transplant Recipients.

Data on post-transplant Kaposi's sarcoma in heart and lung transplant recipients are sparse. This study examined the incidence of biopsy-proven post-transplant Kaposi's sarcoma in thoracic organ recipients over a period of 20 years. As mammalian target of rapamycin inhibitors were introduced in 2006 as optional maintenance immunosuppressive therapy, the overall results were analysed and stratified into 2 groups: 1996 to 2005 and 2006 to 2016. A total of 867 transplant recipients met the study criteria. Post-transplant Kaposi's sarcoma was diagnosed in 7 (0.81%) patients. Five cases (0.19% of transplant recipients) were recorded in 1996 to 2005 and 2 (0.03% of transplant recipients) in 2006 to 2016 (p = 0.04). Multivariable logistic regression analyses identified the following as risk factors: period of transplantation (odds ratio (OR) 4.844, 95% confidence interval (95% CI) 1.156-20.291), age at transplantation (OR 1.066, 95% CI 0.992-1.145), and North African origin (OR 7.282, 95% CI 12.55-42.254). This study found a decreased incidence of post-transplant Kaposi's sarcoma over the last 20 years, mainly attributed.

Heart transplant recipients with confirmed 2019 novel coronavirus infection: The Detroit experience.

A chronic immunosuppressed state as in solid organ transplant recipients is a reported risk factor for the novel 2019 coronavirus infection. Patients with a history of orthotopic heart transplant (OHT) at a tertiary care transplant center in Detroit, Michigan were retrospectively reviewed from March until May 2020. Clinical parameters and outcomes of 5 OHT recipients and one combined heart-lung recipient with confirmed SARS-CoV-2 were obtained. The cohort was predominately African American males with median age of 59 years (interquartile range, 48.25-73.25). All patients were classified as having mild-moderate disease; none required intubation or ICU admission with no deaths. The most common presenting symptoms were fever and shortness of breath 83% (n = 5), followed by cough and chills 67% (n = 4). All admitted patients (n = 5) received hydroxychloroquine and 3 received high-dose steroids. Antimetabolites were held for 2 patients (33.3%). The calcineurin inhibitor trough goal was decreased in only 1 patient; 3 other patients, without change in goal, required calcineurin inhibitor dosage reduction. Two patients requiring readmission presented 7 and 23 days after initial symptoms onset. In conclusion, our experience with OHT patients infected by the SARS-CoV-2 virus did not have an elevated risk of severe infection. Impact of modifying immunosuppression remains unclear.

Global longitudinal strain assessment of the left ventricle by speckle tracking echocardiography detects acute cellular rejection in orthotopic heart transplant recipients: A systematic review and meta-analysis.

BACKGROUND: In orthotopic heart transplant recipients, surveillance with endomyocardial biopsy is crucial to detect acute cellular rejection (ACR) early. ACR is a common and serious complication of transplantation with substantial morbidity and mortality. Speckle tracking echocardiography with global longitudinal strain (GLS) assessment of the left ventricle has emerged as a possible noninvasive screening modality. We have conducted a systematic literature review and meta-analysis to evaluate the role of GLS in diagnosing ACR. METHODS: The following databases were queried: PubMed, Cochrane Central Register of Controlled Trials (CENTRAL), Scopus, and Embase. We compiled all articles evaluating changes in GLS in comparison to endomyocardial biopsy in ACR dated prior to September 2019. Weighted mean differences (WMD) and 95% confidence intervals (CIs) were pooled by using a random effects model. In order to determine the risk of bias, we used the revised version of the Quality Assessment of Diagnostic Accuracy Studies (QUADAS-2) tool. RESULTS: Twelve studies met inclusion criteria of which ten were chosen. These studies encompassed 511 patients and 1267 endomyocardial biopsies. There was a significant difference in GLS between patients who did and did not have ACR proven by biopsy (WMD = 2.18; 95% CI: 1.57-2.78, P = <.001; I2  = 76%). The overall sensitivity for GLS in detecting ACR was 78% (CI: 63%-90%, P = .123; I2  = 52.2%) while the overall specificity was 68% (CI: 50%-83%, P = <.001; I2  = 88.3%). CONCLUSION: Global longitudinal strain assessment of the left ventricle by speckle tracking echocardiography is useful in detecting ACR and could potentially reduce the burden of frequent endomyocardial biopsies in heart transplant recipients.

Prediction of long-term (> 10 year) cardiovascular outcomes in heart transplant recipients: Value of stress technetium-99m tetrofosmin myocardial perfusion imaging.

BACKGROUND: Myocardial perfusion imaging (MPI) using single-photon emission computed tomography (SPECT) is useful in the evaluation of cardiac allograft vasculopathy (CAV) in heart transplant (HTx) recipients. The current study evaluated the long-term prognostic value of stress SPECT MPI for predicting all-cause mortality and cardiac events in HTx recipients. METHODS: The study population consisted of 166 HTx recipients (mean age 54 ± 10 years, 84% male) who underwent exercise or dobutamine stress 99mTc-tetrofosmin SPECT MPI for the assessment of CAV. An abnormal SPECT MPI was defined as the presence of a fixed or a reversible perfusion defect. Endpoints were all-cause mortality, cardiac mortality, and non-fatal myocardial infarction (MI). RESULTS: MPI abnormalities were detected in 55 patients (33%), including fixed defects in 28 patients (17%), partially reversible in 17 patients (10%), and completely reversible defects in 10 patients (6%). During a median follow-up of 12.8 years (range 0-15, mean follow-up 9.5 years), 109 (66%) patients died (all-cause mortality), of which 67 (40%) were due to cardiac causes. A total of 5 (3%) patients experienced a non-fatal MI. HTx recipients with a normal stress 99mTc-tetrofosmin SPECT MPI had a significantly better prognosis as compared with those with an abnormal study, up to 5 years after the initial test. The presence of a reversible perfusion defect was a significant predictor of all-cause mortality, cardiac mortality, and major cardiac events, during the entire follow-up period. CONCLUSIONS: Stress 99mTc-tetrofosmin SPECT MPI provides valuable prognostic information for the prediction of long-term outcome in HTx recipients. Patients with a normal stress 99mTc-tetrofosmin SPECT MPI have a significantly better prognosis as compared with those with an abnormal study, up to 5 years after initial testing.

Atrial function in heart transplant recipients operated with the bicaval technique.

OBJECTIVES: In heart transplantation (HTx) with the bicaval technique the whole right atrium (RA) is donor tissue while the left atrium (LA) consists of both donor and recipient tissue. The aims of the study were to describe atrial function in comparison with healthy controls and to identify determinants of dysfunction. DESIGN: Forty-three patients and 30 controls were retrospectively included. Echocardiography was performed within 24 h of right heart catheterization (RHC) (HTx recipients). RESULTS: The peak longitudinal atrial systolic strain (ɛ) described the atrial reservoir function. The LA and RA reservoir function were reduced versus controls (LA-ɛ 18 ± 8 versus 44 ± 10%; RA-ɛ 22 ± 10 versus 69 ± 17%, p < 0.001). There were moderate relationships between atrial-ɛ and ventricular filling pressure (r = -0.64 for LA-ɛ; r = -0.57 for RA-ɛ). In a multiple regression analysis the LA-ɛ was determined by pulmonary capillary wedge pressure (PCWP) and LA minimum volume index (r = -0.71) while RA-ɛ was dependent on the right ventricular ɛ (r = -0.77). CONCLUSIONS: Atrial reservoir function is markedly reduced in HTx recipients related to elevated PCWP and LA-enlargement in the LA and in the RA impaired longitudinal right ventricular function.

Occurrence of neuropathies in patients with severe heart failure before and after heart transplantation.

Neuropathies may affect heart reinnervation and functional outcome after heart transplantation (HT). In this study, neurological evaluations, standard nerve conduction studies, and electromyography were performed in 32 HT candidates without a previous history of neuromuscular disorder. Ten patients underwent HT and were revaluated 3 months later. We found that before HT 10 (31.3%) patients had sensorimotor polyneuropathy (18.8%) or sensory polyneuropathy (12.5%). After HT, the percentage of patients with a neuromuscular disorder increased to 70%, most of them showing new or worsening neuropathies or neuromyopathies. The most sensitive abnormality that indicated neuromuscular involvement after HT was a reduction of the compound muscle action potential (CMAP) of the deep peroneal nerve. In conclusion, neuromuscular disorders are common in HT candidates, and they further increase in occurrence after HT. A reduction of the deep peroneal nerve CMAP amplitude after HT may help to identify patients who need a more detailed neurophysiological evaluation. The diagnosis of neuromuscular disorders before and after HT may contribute to the development of more accurate therapeutic and rehabilitative strategies for these patients.

Constrictive pericarditis following cardiac transplantation: a report of two cases and a literature review.

The data on constrictive pericarditis following heart transplantation are scarce. Herein, the authors present 2 patients who developed a constrictive pericarditis 19, and 55 months after heart transplantation. They underwent several diagnostic procedures and successfully recovered after a radical pericardiectomy. In addition, the authors review the literature and report the incidence, aetiology, diagnostic features, and management of this rare and challenging condition.

Severity of SARS-CoV-2 Omicron variant infection in heart transplant recipients.

SARS-CoV-2 Omicron variant was first detected in France mid-November 2021 in wastewater treatment plants while cases started to increase at the beginning of December. The maximum incidence occurred in mid-January 2022. The Omicron wave spread rapidly throughout France in general population with lower case-fatality rate compared with previous waves. Little is known about infection with Omicron variant in heart transplant (HT) recipients. In this study, we examined incidence and mortality rate of COVID-19 in the general population and among 1,263 HT recipients during the period from June, 2021 to February, 2022, described characteristics of HT recipients infected with SARS-CoV-2 during Omicron (December 1st, 2021-February 7, 2022) and Delta (June 1st- November 30, 2021) periods, and compared hospital course of HT recipients with Omicron and Delta variant infection. Our findings contrast with the reported lower severity for Omicron variant infection compared with Delta variant infection in immunocompetent individuals.

Third dose of the BNT162b2 vaccine in cardiothoracic transplant recipients: predictive factors for humoral response.

BACKGROUND: We report the results of a prospective study on the immunogenicity of a 3rd dose of BNT162b2 in thoracic organ recipients with no or minimal response following a two-dose BNT162b2 vaccination scheme. METHODS: A total of 243 transplant recipients received a homologue 3rd dose. Anti-SARS-CoV2-immunoglobulins (IgGs) were monitored immediately before (T1), 4 weeks (T2) as well as 2 and 4 months after the 3rd dose. Neutralizing antibody capacity (NAC) was determined at T2. To reveal predictors for detectable humoral response, patients were divided into a positive response group (n = 129) based on the combined criteria of IgGs and NAC above the defined cut-offs at T2-and a group with negative response (n = 114), with both, IgGs and NAC beyond the cut-offs. RESULTS: The 3rd dose induced a positive humoral response in 53% of patients at T2, 47% were still non-responsive. Sero-positivity was significantly stronger in patients who presented with weak, but detectable IgGs already prior to the booster (T1), when compared to those with no detectable response at T1. Multivariable analysis identified age > 55 years, a period since transplantation < 2 years, a reduced glomerular filtration rate, a triple immunosuppressive regimen, and the use of tacrolimus and of mycophenolate as independent risk factors for lack of humoral response. CONCLUSIONS: Our data indicate that a lack of immunogenicity is linked to the type and extent of maintenance immunosuppression. The necessity of the cumulative immunosuppressive regimen might individually be questioned and possibly be reduced to enhance the chance of an immune response following an additional booster dose.

Introduction of machine perfusion of donor hearts in a single center in Germany.

Introduction: Organ shortage, subsequent use of extended donor criteria organs and high-risk recipients needing redo-surgery are increasing the complexity of heart transplantation. Donor organ machine perfusion (MP) is an emerging technology allowing reduction of ischemia time as well as standardized evaluation of the organ. The aim of this study was to review the introduction of MP and analyze the results of heart transplantation after MP in our center. Methods: In a retrospective single-center study, data from a prospectively collected database were analysed. From July 2018 to August 2021, fourteen hearts were retrieved and perfused using the Organ Care System (OCS), 12 hearts were transplanted. Criteria to use the OCS were based on donor/recipient characteristics. Primary objective was 30-day survival, secondary objectives were major cardiac adverse events, graft function, rejection episodes as well as overall survival in the follow-up and assessment of MP technical reliability. Results: All patients survived the procedure and the postoperative 30-day interval. No MP related complications were noted. Graft ejection fraction beyond 14 days was ≥ 50% in all cases. Endomyocardial biopsy showed excellent results with no or mild rejection. Two donor hearts were rejected after OCS perfusion and evaluation. Conclusion: Ex vivo normothermic MP during organ procurement is a safe and promising technique to expand the donor pool. Reduction of cold ischemic time while providing additional donor heart assessment and reconditioning options increased the number of acceptable donor hearts. Additional clinical trials are necessary to develop guidelines regarding the application of MP.

Accuracy of echocardiographic estimations of right heart pressures in adult heart transplant recipients.

BACKGROUND: Accurate assessment of right atrial pressure (RAP) and pulmonary artery systolic pressure (PASP) is critical in the management of heart transplant recipients. The accuracy of echocardiography in estimating these pressures has been debated. OBJECTIVE: To assess the correlation and agreement between echocardiographic estimations of right heart pressures with those of respective invasive hemodynamic measurements by right heart catheterization (RHC) in adult heart transplant recipients. METHODS: This is a prospective evaluation of 84 unique measurements from heart transplant recipients who underwent RHC followed by standard echocardiographic evaluation within 159 ± 64 min with no intervening medication changes. The relationship between noninvasive pressure estimations and invasive hemodynamic measurements was examined. RESULTS: Mean RAP was 7 ± 5 mmHg and mean PASP was 33 ± 8 mmHg by RHC. There was no significant correlation between echocardiographic estimation of RAP and invasive RAP (Spearman's rho = -0.05, p = .7), and no significant agreement between these two variables (weighted kappa = -0.1). There was a modest correlation between echocardiographic estimation of PASP and invasive PASP (r = .39, p = .002). Bland-Altman analysis showed a mean bias of 2.1 ± 9 mmHg (limits of agreement = -15 to 20 mmHg). CONCLUSION: In heart transplant recipients, there is no significant correlation or agreement between echocardiographic RAP estimation and invasively determined RAP. Noninvasive PASP estimation correlates significantly but modestly with invasively measured PASP. Further refinement of echocardiographic methods for assessment of RAP is warranted in this unique patient population.

COVID-19 in Heart Transplant Recipients: A Multicenter Analysis of the Northern Italian Outbreak.

OBJECTIVES: The aim of this study was to assess the clinical course and outcomes of all heart transplant recipients affected by coronavirus disease-2019 (COVID-19) who were followed at the leading heart transplant centers of Northern Italy. BACKGROUND: The worldwide severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) pandemic has created unprecedented challenges for public health, demanding exceptional efforts for the successful management and treatment of affected patients. Heart transplant patients represent a unique cohort of chronically immunosuppressed subjects in which SARS-CoV-2 may stimulate an unpredictable clinical course of infection. METHODS: Since February 2020, we enrolled all 47 cases (79% male) in a first cohort of patients, with a mean age of 61.8 ± 14.5 years, who tested positive for SARS-CoV-2, out of 2,676 heart transplant recipients alive before the onset of the COVID-19 pandemic at 7 heart transplant centers in Northern Italy. RESULTS: To date, 38 patients required hospitalization while 9 remained self-home quarantined and 14 died. Compared to the general population, prevalence (18 vs. 7 cases per 1,000) and related case fatality rate (29.7% vs. 15.4%) in heart transplant recipients were doubled. Univariable analysis showed older age (p = 0.002), diabetes mellitus (p = 0.040), extracardiac arteriopathy (p = 0.040), previous PCI (p = 0.040), CAV score (p = 0.039), lower GFR (p = 0.004), and higher NYHA functional classes (p = 0.023) were all significantly associated with in-hospital mortality. During the follow-up two patients died and a third patient has prolonged viral-shedding alternating positive and negative swabs. Since July 1st, 2020, we had 6 new patients who tested positive for SARS-CoV-2, 5 patients asymptomatic were self-quarantined, while 1 is still hospitalized for pneumonia. A standard therapy was maintained for all, except for the hospitalized patient. CONCLUSIONS: The prevalence and mortality of SARS-CoV-2 should spur clinicians to immediately refer heart transplant recipients suspected as having SARS-CoV2 infection to centers specializing in the care of this vulnerable population.

Usefulness of dual imaging stress echocardiography for the diagnosis of coronary allograft vasculopathy in heart transplant recipients.

BACKGROUND: Coronary allograft vasculopathy (CAV) is the main factor limiting long-term survival after cardiac transplantation. Dual imaging stress echocardiography with wall motion and Doppler-derived coronary flow reserve (CRF) of the left anterior descending artery (LAD) is a state-of-the-art methodology during dipyridamole stress echocardiography (DiSE). This study involving 74 heart transplanted patients has the purpose to assess the diagnostic value of dipyridamole stress echocardiography with evaluation of wall motion (WM) and Doppler-derived coronary flow reserve for the diagnosis of coronary allograft vasculopathy. METHODS AND RESULTS: All patients underwent DiSE and coronary angiography. Moderate-severe CAV was defined according to International Society of Heart and Lung Transplant (ISHLT) recommended nomenclature for CAV, and CFR < 2 was considered to be impaired. Moderate-severe CAV was present in 11 patients. WM analysis revealed four patients (5%) with rest WM abnormalities. CFR analysis revealed that 40 (54%) individuals had an abnormal result. The combined evaluation of WM analysis and CFR resulted in a sensitivity of 72.7% (95% CI: 39.3 to 92.6%), a specificity of 49.2% (95% CI: 36.5 to 61.9%), a positive predictive value of 20% (95% CI: 9.6 to 36.1%), and negative predictive value of 91.1% (95% CI: 75.1 to 97.6%) for the diagnosis of CAV. CONCLUSIONS: Our results support the inclusion of DiSE performance in Heart transplant follow up protocol. The addition of CFR evaluation offers valuable information to the angiography findings in the detection of CAV and could be helpful in selected patients to adjust the time and indications of coronary angiography.

Cimetidine: A Safe Treatment Option for Cutaneous Warts in Pediatric Heart Transplant Recipients.

Abstract:Background andObjectives: Immunosuppressed individuals are at particularly increased risk for human papilloma virus-related infections. The primary objective of our study is to determine if there are any adverse effects associated with high-dose cimetidine treatment. A secondary objective is to report our experience with cimetidine in the treatment of cutaneous warts in pediatric heart transplant recipients. Methods and Results: This was a retrospective observational study. A total of 8 pediatric heart transplant recipients diagnosed with multiple recalcitrant warts were the subject of the study. All patients were treated with cimetidine (30-40 mg/kg/day) in two divided doses for 3 to 6 month durations. All patients had complete resolution of their lesions except 1 patient who had no clinical improvement. Of these 8 patients, one had recurrence of warts at one year follow-up, which resolved with restarting cimetidine therapy. One patient who had only 3 months of cimetidine therapy had immediate relapse after cimetidine was stopped. None of them had significant change in their tacrolimus trough, serum creatinine, and alanine transaminase levels. No adverse events were reported except one patient experienced mild gynecomastia. Conclusion: Cimetidine can be a safe and alternative treatment option for multiple warts in pediatric heart transplant recipients.

Optical coherence tomography for characterization of cardiac allograft vasculopathy in late survivors of pediatric heart transplantation.

BACKGROUND: Optical coherence tomography (OCT) has been shown to reliably detect cardiac allograft vasculopathy (CAV). In recent studies performed in adult heart transplant (HTx) recipients, OCT revealed the presence of vulnerable plaques and complicated coronary artery lesions, thus challenging the current concept that CAV disease is a diffuse concentric and fibrosing vasculopathy. The aim of our study was to characterize CAV by OCT in a young population of HTx recipients. METHODS: We prospectively enrolled 21 young HTx recipients (mean age 27 years, range 22 to 38 years) to undergo OCT of the left anterior descending coronary artery (LAD) in addition to annual CAV screening by coronary angiography and virtual histology intravascular ultrasound (VH-IVUS). Quantitative OCT analysis was performed at the site of maximal intimal thickness (MIT) for each LAD segment. RESULTS: Patients were 27 years old with a mean time from cardiac transplantation of 14.7 ± 6.8 years. All patients exhibited intimal hyperplasia with an abnormal (>1) intima-to-media ratio. The median (interquartile range) MIT values by OCT were 0.37 (0.22 to 0.54) mm, 0.46 (0.29 to 0.54) mm and 0.34 (0.25 to 0.49) mm in the distal, middle and proximal LAD segments, respectively. Qualitative OCT analysis rarely showed features of vulnerable plaque or complicated lesions. Consistently, at VH-IVUS, the prevalent component at the site of MIT per vessel assessed by OCT was fibrous tissue. CONCLUSIONS: Unlike recent evidence in adult HTx recipients, OCT findings of vulnerable plaque and complicated coronary lesions were found to be rare among late survivors of pediatric HTx.