Heart transplant prolongs life for patients with end-stage heart failure but rejection remains a complication that reduces long-term survival. The aim is to provide a comprehensive overview of the current status in HT rejection. EMB is an invasive diagnostic tool, consisting in the sampling of a fragment of myocardial tissue from the right ventricular septum using fluoroscopic guidance. This tissue can later be subjected to histopathological, immunohistochemical or molecular analysis, providing valuable information for cardiac allograft rejection, but this procedure is not without complications. To increase the accuracy of the rejection diagnosis, EMB requires a systematic evaluation of endocardium, myocardium, interstitium and intramural vessels. There are three types of rejection: hyperacute, acute or chronic, diagnosed by the histopathological evaluation of EMB as well as by new diagnostic methods such as DSA, ddcfDNA and gene expression profiling, the last having a high negative predictive value. More than 50 years after the introduction of EMB in medical practice, it still remains the “gold standard” in monitoring rejection in HT recipients but other new, less invasive diagnostic methods reduce the number of EMBs required.

Over the past few decades, a series of innovative medicines have been developed in order to optimize anticoagulation therapy for atrial fibrillation (AF). As a result, a number of nonvitamin K antagonist oral anticoagulants (NOAC) that directly target the enzymatic activity of factor II and factor Xa have been successfully licensed providing a more predictable effect and better safety profile compared to conventional anticoagulants (heparins and vitamin K antagonists (VKAs)). However, comparative efficacy and safety data is limited in patients with advanced chronic kidney disease (i.e., CKD stage 4/5 and end stage renal disease) because patients with estimated glomerular filtration rate (eGFR) < 30 mL/min/1.73 m² were actively excluded from landmark trials, thus representing a major clinical limitation for the currently available agents. However, the renal function of AF patients can be altered over time. On the other hand, patients with CKD have an increased risk of developing AF. This review article will provide an overview of current concepts and recent evidence guiding the clinical use of NOACs in patients with CKD requiring chronic anticoagulation, and the associated risks and benefits of treatment in this specific patient population.

Background: Heart transplantation (HT) remains the ultimate treatment for end-stage heart failure. An endomyocardial biopsy (EMB) is “the gold standard” diagnostic procedure used in HT rejection surveillance. The aim of this study is to provide a detailed analysis of the histopathological characteristics of the EMB and to investigate if there is a correlation between some histopathological changes, such as fibrosis, vasculitis, Quilty effect (Q.E.), myocytes damage, and the presence of episodes of acute rejection. Methods: In this retrospective study, 200 EMBs were included, coming from 65 patients transplanted in the Emergency Institute for Cardiovascular Diseases and Transplantation (ICvDT) Targu Mures between 2012 and 2024. Fibrosis, vasculitis, Q.E., myocyte damage, etc., were microscopically evaluated to see if these parameters correlate with rejection episodes. Results: The mean age was 38.18 years (SD 15.67), 25% of biopsies being recorded in the 41–50 age group. 77.14% of total acute cellular rejection (ACR) was of mild rejection, with most registered in the 11–20 age group; the cases of severe rejection being recorded in the 41–50 age group. Antibody-mediated rejection (AMR) was recorded more frequently in women with a representation of 23.4%, compared to 8.5% of men. 86.7% (39 cases) of the total number of EMBs with fibrosis score 3 and 71.4% (15 cases) of the total EMBs with fibrosis score 2 were recorded in men, compared to the 28.6% (6 cases) of fibrosis score 2 recorded in women (p = 0.013). 50.0% of all the EMB recorded in the 61–70 age group showed fibrosis score 3, compared to 34.8% of those from the 21–30 age group. The Q.E. was identified in 13% of the biopsies and, in some patients, it was observed across 3–4 successive biopsies. Mild vasculitis was associated in 34.9% of cases with ISHLT ≥ 1R and moderate vasculitis was associated in 87.5% of cases with ISHLT ≥ 1R. Conclusions: Fibrosis was detected much more frequently in men and in the 61–70 age group. In addition to the histopathological changes specific to acute rejection, there are other pathological changes, such as the Q.E., and vasculitis and myocytes damage and disarray, that seem to suggest a close connection with rejection, but extensive studies are needed to confirm this.

Background: CAV (cardiac allograft vasculopathy) is considered the leading cause of late post-transplant mortality and affects approximately 50% of transplant patients at 10 years post-transplant. Its etiopathogenetic mechanism is considered to be immune-mediated, but the identification of other non-immunological risk factors could represent new therapeutic targets for this pathology. Lipofuscin is due to reactive oxygen species (ROS) and appears to have a determining role in CAV. The aim of this study is to investigate the association between the amount of lipofuscin identified on EMB (endomyocardial biopsy) from patients followed up after heart transplantation, and the presence of CAV detected by coronary angiography. Methods: This retrospective study includes 99 EMBs from 47 transplanted patients, who also had coronary angiography. The amount of lipofuscin, damage to intramyocardial small vessels, vasculitis, Quilty effect, and acute cellular and humoral rejection was evaluated microscopically. Results: 19 CAV cases (19.2%) were identified, of which 15 (68.18% of total CAV cases) were insignificant. Grade 3 lipofuscin affected equally the cases with insignificant and significant CAV, 3 cases (37.5%) from each group. Grade 2 lipofuscin was reported in 10 cases (58.8%) of insignificant CAV, respectively 1 case of significant CAV (5.9%), (p-value of 0.0001). Quantitative evaluation of lipofuscin on microscopic sections revealed 8 EMBs (8.1%) with grade 3 lipofuscin. Two cases (25.0%) with lipofuscin score 3 were associated with moderate ACR (acute cellular rejection), ISHLT 2R and 3 cases (37.5%) with lipofuscin score 3 were associated with mild ACR ISHLT 1R, the differences being statistically significant, (p = 0.0001). Lipofuscin grades 2 and 3 were associated with severe fibrosis in 6 cases (35.3%) and 2 cases (25.0%), respectively (p = 0.042). A statistically significant association between the degree of damage to the intramyocardial small vessels and the amount of intracytoplasmic lipofuscin was observed (p = 0.00014). Discussion: Our study revealed that lipofuscin was more frequently associated with CAV, fibrosis, and damaged small vessels. Oxidative stress influences lipofuscinogenesis and CAV, which leads to endothelial dysfunction and neointimal hyperplasia, which over time will produce progressive narrowing of the vascular lumen and dysfunction of the cardiac allograft. Of the total number of 19 cases with CAV, 17 (89.47%) presented a lipofuscin score of 2 or 3 concomitantly with CAV, (p = 0.0001). This could mean that lipofuscin is not a harmless degradation product. At the same time, the association of a large number of cases with lipofuscin score 2, 10 cases (58.8%) with insignificant CAV could lead to the idea of using lipofuscin as a potential biomarker in the early diagnosis of CAV. Conclusions: We evidenced a significant association between the amount of intracytoplasmic lipofuscin and CAV. Accordingly, lipofuscin might be involved in the pathogenesis of CAV. Further research is needed to clarify the exact mechanisms of this association.