Heart Transplant and Donors After Circulatory Death: A Clinical-Preclinical Systematic Review

The Influence of Social Determinants of Health on the Survival of Heart Transplants in the Pediatric Age: An Analysis of a Mexican Cohort and Its Comparison with Latin America and the Caribbean

Background/Objectives: A heart transplantation (HT) is the definitive treatment for heart failure. There is a difference in the success between national HT programs in developed countries and those in Central America, South America, and the Caribbean (LAC), and social determinants of health (SDHs) can directly influence this. The objectives of this study were to describe the survival since the beginning of the HT program of a national pediatric institute in Mexico City and to compare it with the results of a systematic review of LAC. Methods: A cohort study of a pediatric hospital (which performed 42% of the pediatric HTs in Mexico) was performed since the beginning of the HTs program in 2001. Clinical variables related to the transplants were identified, and the SDHs were divided into three categories: personal, family, and community. A systematic literature review was performed using keywords and a search in the medical indexes of LAC countries. The statistical analysis included descriptive statistics and a bivariate survival analysis. A risk calculation was estimated using the hazard ratio (HR) of the SDHs. Results: A total of 38 HTs were performed, the median age was 7 (4-16) years, and 22 (58%) were men. The leading cause was cardiomyopathy in 20 (53%) cases. The first-year survival rate was 76.3 per 100 HTs. The SDHs that increased the risk of death were suboptimal immunosuppression, the persistence of malnutrition, parental education, the distance from the center, the socioeconomic level, and the absence of transitional care. Conclusions: This cohort of pediatric patients with HTs resulted in the identification of risk variables of personal and community SDHs for mortality in the first and fifth years. Chronic rejection occurred in 50%, and the absence of transitional care to adulthood was the variable with the highest risk. The systematic review identified Mexico as the country with the second-highest frequency of HTs, and our cohort represented 42% of the total number of transplants in the country. Numerically, LAC has a lower frequency of transplants and survival in the first year compared to other developed countries, possibly due to a gap associated with organizational justice.

Heart transplant donation after circulatory death: current status and implications

PURPOSE OF REVIEW

The use of cardiac transplantation following circulatory death (DCD) has been limited worldwide. Concerns about cardiac function after warm ischemia and the potential for decreased graft function have been important considerations in this hesitancy. In addition, ethical and legal questions about the two widely used organ procurement methods have led to discussions and public education in many countries.

RECENT FINDINGS

Publication of a US randomized trial of cardiac transplantation following DCD has shown that it is both feasible and has similar short-term outcomes compared with cardiac transplantation following brain death (DBD). These data support those from both Australia and the UK who have largest experience to date.

SUMMARY

The adoption of cardiac transplantation following circulatory death has increased overall cardiac transplantation in those transplant centers who have incorporated these donors. Short term outcomes for DCD organ procurement methods are similar to those outcomes using DBD hearts. Continued study and standardization of warm ischemic times will allow for better comparisons of organ procurement techniques and organ optimization. The ethical concerns about procurement methods, in addition to a discussion of procurement costs and feasibility will need to be addressed further in the efforts to expand the organ pool and increase overall cardiac transplantation numbers.

[Histological and ultrastructural analysis of biopsy specimens of donor heart under conditions of extended period of pharmaco-cold ischaemia]

OBJECTIVE

At the histological and ultramicroscopic level, compare biopsy specimens of donor heart under standard (up to 240 min) and extended (more than 240 min) periods of pharmaco-cold preservation.

MATERIAL AND METHODS

Biopsy specimens of the left atrium of donor hearts: group 1 - 8 samples after transportation with pharmaco-cold preservation of the graft in Bretschneider solution (Dr. Franz Köhler Chemie GmbH, Germany) up to 240 min, (Me 140), and group 2 - 5 samples after an extended pharmaco-cold period (more than 240 min; Me 375) were examined using light microscopy of semi-thin sections and transmission electron microscopy, followed by stereological and statistical analysis.

RESULTS

A comparative study of the myocardium of donor hearts revealed stereotypical dystrophic changes in cardiomyocytes. Semi-thin sections demonstrated a mosaic pattern of myocardial parenchyma in both groups, caused by contracture and less pronounced lytic changes in myocytes, which were accompanied by stromal edema without statistically significant differences according to stereological studies. Ultrathin sections of the perinuclear zones of cardiomyocytes visualized reduction and focal damage to myofibrils and mitochondria in combination with pronounced autophagy; at the same time, with a shorter duration of the pharmaco-cold period, the stereological indicators of cardiomyocyte organelles indicated a relatively better supply of myofibrils with mitochondria.

CONCLUSION

The results obtained suggest a sufficiently high degree of preservation of the tissue and ultrastructural organization of donor hearts with prolonged (more than 240 min) pharmaco-cold ischemia to restore adequate cardiac activity after heart transplantation.