Bronchiectasis After Solid-Organ Transplant: A Retrospective Single Center Study.

OBJECTIVES: Bronchiectasis is characterized by abnormal, persistent, and irreversible enlargement of the bronchi. Many etiological factors have been described, but there are limited data on the development of bronchiectasis after organ transplantation. Our study is the first to study evaluate the frequency of bronchiectasis in heart and liver transplants as well as kidney transplants. Our aim is to analyze the frequency of bronchiectasis development after solid-organ transplant and the characteristics of the cases and to evaluate potential relationships. MATERIALS AND METHODS: We retrospectively analyzed data of patients who underwent solid-organ transplant at the Baskent University Faculty of Medicine Hospital through the hospital electronic information system. Demographic, clinical, and laboratory data and thoracic computed tomography scans were evaluated. RESULTS: The study included 468 patients (151 females/317 males). Kidney transplant was performed in 61.5% (n = 207), heart transplant in 20.3% (n = 95), and liver transplant in 18.2% (n = 85) of patients. Development of bronchiectasis was detected in only 13 patients (2.7%). We determined a 13.64-fold risk of developing bronchiectasis in patients with chronic obstructive pulmonary disease and 10.08-fold risk in patients with pneumonia by multivariate regression analyzes, in which all possible risk factors for the development of bronchiectasis after transplant were evaluated. CONCLUSIONS: The pathophysiology of transplantassociated bronchiectasis has not yet been clarified. Underlying diseases, recurrent pulmonary infections, and potential effects from immunosuppressive drugs may contribute to the pathogenesis of bronchiectasis. Further prospective studies are needed to include long-term health outcomes in transplant patients with and without bronchiectasis.

Primary prophylaxis with mTOR inhibitor enhances T cell effector function and prevents heart transplant rejection during talimogene laherparepvec therapy of squamous cell carcinoma.

The application of mammalian target of rapamycin inhibition (mTORi) as primary prophylactic therapy to optimize T cell effector function while preserving allograft tolerance remains challenging. Here, we present a comprehensive two-step therapeutic approach in a male patient with metastatic cutaneous squamous cell carcinoma and heart transplantation followed with concomitant longitudinal analysis of systemic immunologic changes. In the first step, calcineurin inhibitor/ mycophenolic acid is replaced by the mTORi everolimus to achieve an improved effector T cell status with increased cytotoxic activity (perforin, granzyme), enhanced proliferation (Ki67) and upregulated activation markers (CD38, CD69). In the second step, talimogene laherparepvec (T-VEC) injection further enhances effector function by switching CD4 and CD8 cells from central memory to effector memory profiles, enhancing Th1 responses, and boosting cytotoxic and proliferative activities. In addition, cytokine release (IL-6, IL-18, sCD25, CCL-2, CCL-4) is enhanced and the frequency of circulating regulatory T cells is increased. Notably, no histologic signs of allograft rejection are observed in consecutive end-myocardial biopsies. These findings provide valuable insights into the dynamics of T cell activation and differentiation and suggest that timely initiation of mTORi-based primary prophylaxis may provide a dual benefit of revitalizing T cell function while maintaining allograft tolerance.

Postoperative cognitive dysfunction in heart transplantation recipients.

OBJECTIVE: This study aimed to investigate the occurrence and risk factors of postoperative neurocognitive disorder (NCD) in patients who underwent heart transplantation. METHODS: Seventy-six heart transplant patients were analyzed for clinical data including gender, age, height, weight, education level, left ventricular ejection fraction (LVEF), stroke volume (SV), transplantation duration, and pretransplant medical history. Cognitive function was assessed using the mini-mental status examination (MMSE) and Montreal cognitive assessment (MoCA) scales. Patients were categorized into cognitively normal and impaired groups based on the presence or absence of cognitive dysfunction, and their cognitive function scores were compared. Multivariate logistic regression was used to identify independent risk factors for cognitive impairment in postoperative cardiac transplant patients. RESULTS: Cognitive dysfunction was observed in 48 out of 76 heart transplant patients, representing an incidence of 63.2%. Cognitive impairment in heart transplant recipients predominantly affected multiple cognitive domains. Logistic regression analysis identified age (OR = 1.057, 95% CI 1.002-1.115), gender (OR = .200, 95% CI .044-.919), education level (OR = .728, 95% CI .600-.883), LVEF (OR = .891, 95% CI .820-.969), and history of diabetes (OR = 7.674, 95% CI 1.317-44.733) as independent risk factors for postoperative NCD in heart transplant recipients (P < .05). CONCLUSION: The study found a high incidence of postoperative NCD in heart transplant patients, with gender, age, education level, LVEF, and diabetes history being significant risk factors. Early identification and intervention targeting these risk factors may help prevent NCD in postheart transplant patients and improve long-term outcomes.

Biomarkers from subcutaneous engineered tissues predict acute rejection of organ allografts.

Invasive graft biopsies assess the efficacy of immunosuppression through lagging indicators of transplant rejection. We report on a microporous scaffold implant as a minimally invasive immunological niche to assay rejection before graft injury. Adoptive transfer of T cells into Rag2-/- mice with mismatched allografts induced acute cellular allograft rejection (ACAR), with subsequent validation in wild-type animals. Following murine heart or skin transplantation, scaffold implants accumulate predominantly innate immune cells. The scaffold enables frequent biopsy, and gene expression analyses identified biomarkers of ACAR before clinical signs of graft injury. This gene signature distinguishes ACAR and immunodeficient respiratory infection before injury onset, indicating the specificity of the biomarkers to differentiate ACAR from other inflammatory insult. Overall, this implantable scaffold enables remote evaluation of the early risk of rejection, which could potentially be used to reduce the frequency of routine graft biopsy, reduce toxicities by personalizing immunosuppression, and prolong transplant life.

A heart transplant center experience with basiliximab induction strategies: A double edged sword?

BACKGROUND: The use of induction immunosuppression for heart transplantation (HT) is debated given the uncertain benefit and potential risks of infection and malignancy. METHODS: This is a retrospective single-center analysis of 475 consecutive HT recipients from 2003 to 2020 grouped by use of induction with basiliximab group (BG) and the no basiliximab group (NBG). Subgroup analysis by era compared pre-2016 standard-basiliximab (BX) induction and 2016-2020 with selective-BX use as part of a calcineurin-inhibitor-sparing regimen. RESULTS: When adjusted for confounders (sex, age, PRA, eGFR), the BG was less likely to have acute cellular rejection (ACR) (OR.42, p < .001), but had more antibody mediated rejection (AMR) (OR 11.7, p < .001) and more cardiac allograft vasculopathy (CAV) (OR 3.8, p = .04). There was no difference between BG and NBG in the incidence of malignancies or infections. When stratified by era (pre-2016 vs. 2016-2020), ACR remained less common in the BG than the NBG (36% vs. 50%, p = .045) groups, while AMR remained more common (9.7 vs. 0% p = .005). There was no significant difference in conditional survival comparing pre-and post-2016 NBG (HR 2.20 (95% CI.75-6.43); however, both pre-2016 BG and post-2016 BG have significantly higher mortality (HR 2.37 [95% CI 1.02-5.50) and HR 2.69 (95% CI 1.08-6.71), p = .045 and.03, respectively]. CONCLUSION: Basiliximab reduces the incidence of ACR but increases the risk of AMR, CAV, and may be associated with increased mortality. Mechanistic studies are needed to describe a potential T-cell-escape mechanism with enhanced humoral immunity.

Right Ventricular Function on Cardiovascular Magnetic Resonance Imaging and Long-Term Outcomes in Stable Heart Transplant Recipients.

BACKGROUND: In heart transplant recipients, right ventricular (RV) dysfunction may occur for a variety of reasons. Whether RV dysfunction in the stable phase after heart transplantation is associated with long-term adverse outcomes is unknown. We aimed to determine the long-term prognostic significance of RV dysfunction identified on cardiovascular magnetic resonance imaging (CMR) at least 1 year after heart transplantation. METHODS: In consecutive heart transplant recipients who underwent CMR for surveillance, we assessed 2 CMR measures of RV function: RV ejection fraction and RV global longitudinal strain (RVGLS). We investigated associations between RV dysfunction and a composite end point of death or major adverse cardiac events, including retransplantation, nonfatal myocardial infarction, coronary revascularization, and heart failure hospitalization. RESULTS: A total of 257 heart transplant recipients (median age, 59 years; 75% men) who had CMR at a median of 4.3 years after heart transplantation were included. Over a median follow-up of 4.4 years after the CMR, 108 recipients experienced death or major adverse cardiac events. In a multivariable Cox regression analysis adjusted for age, time since transplantation, indication for transplantation, cardiac allograft vasculopathy, history of rejection, and CMR covariates, RV ejection fraction was not associated with the composite end point, but RVGLS was independently associated with the composite end point with a hazard ratio of 1.08 per 1% worsening in RVGLS ([95% CI, 1.00-1.17]; P=0.046). RVGLS provided incremental prognostic value over other variables in multivariable analyses. The association was replicated in subgroups of recipients with normal RV ejection fraction and recipients with late gadolinium enhancement imaging. A similar association was seen with a composite end point of cardiovascular death or major adverse cardiac events. CONCLUSIONS: CMR feature tracking-derived RVGLS assessed at least 1 year after heart transplantation was independently associated with the long-term risk of death or major adverse cardiac events. Future studies should investigate its role in guiding clinical decision-making in heart transplant recipients.

Impact of Everolimus Initiation and Corticosteroid Weaning During Acute Phase After Heart Transplantation on Clinical Outcome: Data from the Korean Organ Transplant Registry (KOTRY).

The effect of changes in immunosuppressive therapy during the acute phase post-heart transplantation (HTx) on clinical outcomes remains unclear. This study aimed to investigate the effects of changes in immunosuppressive therapy by corticosteroid (CS) weaning and everolimus (EVR) initiation during the first year post-HTx on clinical outcomes. We analyzed 622 recipients registered in the Korean Organ Transplant Registry (KOTRY) between January 2014 and December 2021. The median age at HTx was 56 years (interquartile range [IQR], 45-62), and the median follow-up time was 3.9 years (IQR 2.0-5.1). The early EVR initiation within the first year post-HTx and maintenance during the follow-up is associated with reduced the risk of primary composite outcome (all-cause mortality or re-transplantation) (HR, 0.24; 95% CI 0.09-0.68; p < 0.001) and cardiac allograft vasculopathy (CAV) (HR, 0.39; 95% CI 0.19-0.79; p = 0.009) compared with EVR-free or EVR intermittent treatment regimen, regardless of CS weaning. However, the early EVR initiation tends to increase the risk of acute allograft rejection compared with EVR-free or EVR intermittent treatment.

The CaMK Family Differentially Promotes Necroptosis and Mouse Cardiac Graft Injury and Rejection.

Organ transplantation is associated with various forms of programmed cell death which can accelerate transplant injury and rejection. Targeting cell death in donor organs may represent a novel strategy for preventing allograft injury. We have previously demonstrated that necroptosis plays a key role in promoting transplant injury. Recently, we have found that mitochondria function is linked to necroptosis. However, it remains unknown how necroptosis signaling pathways regulate mitochondrial function during necroptosis. In this study, we investigated the receptor-interacting protein kinase 3 (RIPK3) mediated mitochondrial dysfunction and necroptosis. We demonstrate that the calmodulin-dependent protein kinase (CaMK) family members CaMK1, 2, and 4 form a complex with RIPK3 in mouse cardiac endothelial cells, to promote trans-phosphorylation during necroptosis. CaMK1 and 4 directly activated the dynamin-related protein-1 (Drp1), while CaMK2 indirectly activated Drp1 via the phosphoglycerate mutase 5 (PGAM5). The inhibition of CaMKs restored mitochondrial function and effectively prevented endothelial cell death. CaMKs inhibition inhibited activation of CaMKs and Drp1, and cell death and heart tissue injury (n = 6/group, p < 0.01) in a murine model of cardiac transplantation. Importantly, the inhibition of CaMKs greatly prolonged heart graft survival (n = 8/group, p < 0.01). In conclusion, CaMK family members orchestrate cell death in two different pathways and may be potential therapeutic targets in preventing cell death and transplant injury.

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.

Disulfiram treatment suppresses antibody-producing reactions by inhibiting macrophage activation and B cell pyrimidine metabolism.

Antibody responses, involving B cells, CD4 + T cells, and macrophages, are implicated in autoimmune diseases and organ transplant rejection. We have previously shown that inhibiting FROUNT with disulfiram (DSF) suppresses macrophage activation and migration, effectively treating inflammatory diseases. In this study, we investigated the effectiveness of DSF in antibody-producing reactions. Using a heart transplantation mouse model with antibody-mediated rejection, we administered anti-CD8 antibody to exclude cellular rejection. DSF directly inhibited B cell responses in vitro and significantly reduced plasma donor-specific antibodies and graft antibody deposition in vivo, resulting in prolonged survival of the heart graft. DSF also mediated various effects, including decreased macrophage infiltration and increased Foxp3+ regulatory T-cells in the grafts. Additionally, DSF inhibited pyrimidine metabolism-related gene expression induced by B-cell stimulation. These findings demonstrate that DSF modulates antibody production in the immune response complexity by regulating B-cell and macrophage responses.

Successful treatment of gastric cancer 10 years after heart transplantation: A case report.

BACKGROUND: While survival rates among cardiac allograft recipients have improved, there has been a rise in post-transplant malignancies, with gastric cancer being less commonly reported. This study presented a successful treatment of gastric cancer in an individual 10 years after undergoing a heart transplant. CASE PRESENTATION: A 66-year-old Chinese man presented to the gastrointestinal clinic with a complaint of diagnosis of gastric cancer for 4 months and treated with neoadjuvant therapy for 1 month. He has undergone orthotopic heart transplantation 10 years earlier due to a myocardial infarction. Physical examination and laboratory tests did not reveal any significant abnormalities. Abdominal contrast-enhanced computed tomography (CT) imaging indicated a gastric mass near the greater curvature, with gastroscopy suggesting a carcinoma at the esophagogastric junction, Siewert III. An echocardiogram indicated left atrial enlargement with mild mitral and tricuspid regurgitation. The diagnosis suggested that his gastric cancer at the esophagogastric junction was a consequence of long-term immunosuppressive therapy. A multidisciplinary team (MDT) consultation recommended a proximal radical gastrectomy. Postoperatively, the patient received 4 cycles of adjuvant chemotherapy with XELOX combined with Herceptin, initiated a month after surgery. During the 1-year follow-up, the patient showed commendable recovery, with no signs of tumor recurrence or metastasis. CONCLUSION: This case underscores the potential risk of malignancy from immunosuppressive agents in transplant recipients. The successful management of this complex scenario underscores the indispensable role of an MDT approach in treating such unique and challenging cases.

Unraveling the Uncommon: A Case Report of Giant Cell Myocarditis and Examination of Existing Literature.

BACKGROUND Idiopathic giant cell myocarditis (IGCM) is an uncommon and frequently fatal type of myocarditis. It primarily affects young individuals and has the potential to result in heart failure and life-threatening arrhythmias. IGCM seems to be dependent on activation of CD4-positive T lymphocytes and can show improvement with treatment aimed at reducing T-cell function. We present a case of a 65-year-old patient who presented with features of acute heart failure refractory to guideline-directed medical therapy (GDMT), due to IGCM. A review of the natural history and treatment of IGCM is also presented. CASE REPORT A 65-year-old woman with multiple comorbidities was admitted to our hospital for ventricular tachycardia in the setting of progressive non-ischemic heart failure, unresponsive to GDMT. This led to further investigation, including an endomyocardial biopsy, which revealed inflammatory infiltration, with multinucleated giant cells and lymphocytes in the absence of granuloma formation, prompting a diagnosis of IGCM. An implantable cardioverter-defibrillator (ICD) was placed for secondary prevention of sudden cardiac death and the patient was initiated on combined immunosuppressive therapy. Owing to numerous comorbidities, she was determined to be unsuitable for a heart transplant. Unfortunately, she eventually died from complications secondary to the disease. CONCLUSIONS IGCM remains a challenging clinical diagnosis with a poor long-term outcome without heart transplantation. This case highlights the importance of considering atypical causes of heart failure in patients who do not respond to conventional therapies. Early recognition and appropriate management, involving medical and interventional approaches, are crucial in improving outcomes for patients with IGCM.

Metabolic Syndrome and Heart Transplantation: An Underestimated Risk Factor?

Metabolic Syndrome (MetS), a multifactorial condition that increases the risk of cardio-vascular events, is frequent in Heart-transplant (HTx) candidates and worsens with immunosuppressive therapy. The aim of the study was to analyze the impact of MetS on long-term outcome of HTx patients. Since 2007, 349 HTx patients were enrolled. MetS was diagnosed if patients met revised NCEP-ATP III criteria before HTx, at 1, 5 and 10 years of follow-up. MetS was present in 35% of patients pre-HTx and 47% at 1 year follow-up. Five-year survival in patients with both pre-HTx (65% vs. 78%, p < 0.01) and 1 year follow-up MetS (78% vs 89%, p < 0.01) was worst. At the univariate analysis, risk factors for mortality were pre-HTx MetS (HR 1.86, p < 0.01), hypertension (HR 2.46, p < 0.01), hypertriglyceridemia (HR 1.50, p=0.03), chronic renal failure (HR 2.95, p < 0.01), MetS and diabetes at 1 year follow-up (HR 2.00, p < 0.01; HR 2.02, p < 0.01, respectively). MetS at 1 year follow-up determined a higher risk to develop Coronary allograft vasculopathy at 5 and 10 year follow-up (25% vs 14% and 44% vs 25%, p < 0.01). MetS is an important risk factor for both mortality and morbidity post-HTx, suggesting the need for a strict monitoring of metabolic disorders with a careful nutritional follow-up in HTx patients.

Role of Radiology in Assessment of Postoperative Complications of Heart Transplantation.

Heart transplantation is a pivotal treatment of end-stage heart failure, and recent advancements have extended median posttransplant life expectancy. However, despite the progress in surgical techniques and medical treatment, heart transplant patients still face complications such as rejection, infections, and drug toxicity. CT is a reliable tool for detecting most of these complications, whereas MR imaging is particularly adept at identifying pericardial pathologies and signs of rejection. Awareness of these nuances by radiologists, cardiologists, and surgeons is desired to optimize care, reduce morbidities, and enhance survival.

Exploring personalized treatment for cardiac graft rejection based on a four-archetype analysis model and bioinformatics analysis.

Heart transplantation is the gold standard for treating patients with advanced heart failure. Although improvements in immunosuppressive therapies have significantly reduced the frequency of cardiac graft rejection, the incidences of T cell-mediated rejection (TCMR) and antibody-mediated rejection remain almost unchanged. A four-archetype analysis (4AA) model, developed by Philip F. Halloran, illustrated this problem well. It provided a new dimension to improve the accuracy of diagnoses and an independent system for recalibrating the histology guidelines. However, this model was based on the invasive method of endocardial biopsy, which undoubtedly increased the postoperative risk of heart transplant patients. Currently, little is known regarding the associated genes and specific functions of the different phenotypes. We performed bioinformatics analysis (using machine-learning methods and the WGCNA algorithm) to screen for hub-specific genes related to different phenotypes, based Gene Expression Omnibus accession number GSE124897. More immune cell infiltration was observed with the ABMR, TCMR, and injury phenotypes than with the stable phenotype. Hub-specific genes for each of the four archetypes were verified successfully using an external test set (accession number GSE2596). Logistic-regression models based on TCMR-specific hub genes and common hub genes were constructed with accurate diagnostic utility (area under the curve > 0.95). RELA, NFKB1, and SOX14 were identified as transcription factors important for TCMR/injury phenotypes and common genes, respectively. Additionally, 11 Food and Drug Administration-approved drugs were chosen from the DrugBank Database for each four-archetype model. Tyrosine kinase inhibitors may be a promising new option for transplant rejection treatment. KRAS signaling in cardiac transplant rejection is worth further investigation. Our results showed that heart transplant rejection subtypes can be accurately diagnosed by detecting expression of the corresponding specific genes, thereby enabling precise treatment or medication.

Use of induction therapy post-heart transplantation: Clinical practice recommendations based on systematic review and network meta-analysis of evidence.

BACKGROUND: The use of induction therapy (IT) agents in the early post-heart transplant period remains controversial. The following recommendations aim to provide guidance on the use of IT agents, including Basiliximab and Thymoglobulin, as part of routine care in heart transplantation (HTx). METHODS: We recruited an international, multidisciplinary panel of 15 stakeholders, including patient partners, transplant cardiologists and surgeons, nurse practitioners, pharmacists, and methodologists. We commissioned a systematic review on benefits and harms of IT on patient-important outcomes, and another on patients' values and preferences to inform our recommendations. We used the GRADE framework to summarize our findings, rate certainty in the evidence, and develop recommendations. The panel considered the balance between benefits and harms, certainty in the evidence, and patient's values and preferences, to make recommendations for or against the routine post-operative use of Thymoglobulin or Basiliximab. RESULTS: The panel made recommendations on three major clinical problems in HTx: (1) We suggest against the routine post-operative use of Basiliximab compared to no IT, (2) we suggest against the routine use of Thymoglobulin compared to no IT, and (3) for those patients for whom IT is deemed desirable, we suggest for the use of Thymoglobulin as compared to Basiliximab. CONCLUSION: This report highlights gaps in current knowledge and provides directions for clinical research in the future to better understand the clinical utility of IT agents in the early post heart transplant period, leading to improved management and care.

COVID-19 infection in patients with history of pediatric heart transplant in Germany, Austria, and Switzerland.

COVID-19 is a heterogenous infection-asymptomatic to fatal. While the course of pediatric COVID-19 infections is usually mild or even asymptomatic, individuals after adult heart transplantation are at high risk of a severe infection. We conducted a retrospective, multicenter survey of 16 pediatric heart transplant centers in Germany, Austria and Switzerland to evaluate the risk of a severe COVID-19 infection after pediatric heart transplantation between 02/2020 and 06/2021. Twenty-six subjects (11 male) with a median age of 9.77 years at time of transplantation and a median of 4.65 years after transplantation suffered from COVID-19 infection. The median age at time of COVID-10 infection was 17.20 years. Fourteen subjects had an asymptomatic COVID-19 infection. The most frequent symptoms were myalgia/fatigue (n = 6), cough (n = 5), rhinitis (n = 5), and loss of taste (n = 5). Only one subject showed dyspnea. Eleven individuals needed therapy in an outpatient setting, four subjects were hospitalized. One person needed oxygen supply, none of the subjects needed non-invasive or invasive mechanical ventilation. No specific signs for graft dysfunction were found by non-invasive testing. In pediatric heart transplant subjects, COVID-19 infection was mostly asymptomatic or mild. There were no SARS-CoV-2 associated myocardial dysfunction in heart transplant individuals.

Acetylsalicylic acid use and development of cardiac allograft vasculopathy: A national prospective study using highly automated 3-D optical coherence tomography analysis.

BACKGROUND: There is conflicting evidence on the role of acetylsalicylic acid (ASA) use in the development of cardiac allograft vasculopathy (CAV). METHODS: A nationwide prospective two-center study investigated changes in the coronary artery vasculature by highly automated 3-D optical coherence tomography (OCT) analysis at 1 month and 12 months after heart transplant (HTx). The influence of ASA use on coronary artery microvascular changes was analyzed in the overall study cohort and after propensity score matching for selected clinical CAV risk factors. RESULTS: In total, 175 patients (mean age 52 ± 12 years, 79% male) were recruited. During the 1-year follow-up, both intimal and media thickness progressed, with ASA having no effect on its progression. However, detailed OCT analysis revealed that ASA use was associated with a lower increase in lipid plaque (LP) burden (p = .013), while it did not affect the other observed pathologies. Propensity score matching of 120 patients (60 patient pairs) showed similar results, with ASA use associated with lower progression of LPs (p = .002), while having no impact on layered fibrotic plaque (p = .224), calcification (p = .231), macrophage infiltration (p = .197), or the absolute coronary artery risk score (p = .277). According to Kaplan-Meier analysis, ASA use was not associated with a significant difference in survival (p = .699) CONCLUSION: This study showed a benefit of early ASA use after HTx on LP progression. However, ASA use did not have any impact on the progression of other OCT-observed pathologies or long-term survival.