RESUMEN
Objectives: To evaluate the clinical implications of adjunctive molecular gene expression analysis (MMDx ) of biopsy specimens in heart transplant (HT ) recipients with suspected rejection. Introduction: Histopathological evaluation remains the standard method for rejection diagnosis in HT. However, the wide interobserver variability combined with a relatively common incidence of "biopsy-negative" rejection has raised concerns about the likelihood of false-negative results. MMDx, which uses gene expression to detect early signs of rejection, is a promising test to further refine the assessment of HT rejection. Methods: Single-center prospective study of 418 consecutive for-cause endomyocardial biopsies performed between November 2022 and May 2024. Each biopsy was graded based on histology and assessed for rejection patterns using MMDx. MMDx results were deemed positive if borderline or definitive rejection was present. The impact of MMDx results on clinical management was evaluated. Primary outcomes were 1-year survival and graft dysfunction following MMDx-guided clinical management. Secondary outcomes included changes in donor-specific antibodies, MMDx gene transcripts, and donor-derived cell-free DNA (dd-cfDNA) levels. Results: We analyzed 418 molecular samples from 237 unique patients. Histology identified rejection in 32 cases (7.7%), while MMDx identified rejection in 95 cases (22.7%). Notably, in 79 of the 95 cases where MMDx identified rejection, histology results were negative, with the majority of these cases being antibody-mediated rejection (62.1%). Samples with rejection on MMDx were more likely to show a combined elevation of dd-cfDNA and peripheral blood gene expression profiling than those with borderline or negative MMDx results (36.7% vs 28.0% vs 10.3%; p<0.001). MMDx results led to the implementation of specific antirejection protocols or changes in immunosuppression in 20.4% of cases, and in 73.4% of cases where histology was negative and MMDx showed rejection. 1-year survival was better in the positive MMDx group where clinical management was guided by MMDx results (87.0% vs 78.6%; log rank p=0.0017). Conclusions: In our cohort, MMDx results more frequently indicated rejection than histology, often leading to the initiation of antirejection treatment. Intervention guided by positive MMDx results was associated with improved outcomes.
RESUMEN
Recent advances in cancer therapy have led to increased survival rates for cancer patients, but also allowed cardiovascular complications to become increasingly evident, with more than 40% of cancer deaths now being attributed to cardiovascular diseases. Cardiotoxicity is the most concerning cardiovascular complication, one caused mainly due to anti-cancer drugs. Among the harmful mechanisms of these drugs are DNA damage, endothelial dysfunction, and oxidative stress. Cancer patients can suffer reduced cardiorespiratory fitness as a secondary effect of anti-cancer therapies, tumor burden, and deconditioning. In the general population, regular exercise can reduce the risk of cardiovascular morbidity, mortality, and cancer. Exercise-induced modifications of gene expression result in improvements of cardiovascular parameters and an increased general fitness, influencing telomere shortening, oxidative stress, vascular function, and DNA repair mechanisms. In cancer patients, exercise training is generally safe and well-tolerated; it is associated with a 10-15% improvement in cardiorespiratory fitness and can potentially counteract the adverse effects of anti-cancer therapy. It is well known that exercise programs can benefit patients with heart disease and cancer, but little research has been conducted with cardio-oncology patients. To date, there are a limited number of effective protective treatments for preventing or reversing cardiotoxicity caused by cancer therapy. Cardiac rehabilitation has the potential to mitigate cardiotoxicity based on the benefits already proven in populations suffering from either cancer or heart diseases. Additionally, the fact that cardiotoxic harm mechanisms coincide with similar mechanisms positively affected by cardiac rehabilitation makes cardiac rehabilitation an even more plausible option for cardio-oncology patients. Due to unstable functional capacity and fluctuating immunocompetence, these patients require specially tailored exercise programs designed collaboratively by cardiologists and oncologists. As the digital era is here, with the digital world and the medical world continuously intertwining, a remote, home-based cardio-oncology rehabilitation program may be a solution for this population.