Considerations for the use of porcine organ donation models in preclinical organ donor intervention research.

Use of animal models in preclinical transplant research is essential to the optimization of human allografts for clinical transplantation. Animal models of organ donation and preservation help to advance and improve technical elements of solid organ recovery and facilitate research of ischemia-reperfusion injury, organ preservation strategies, and future donor-based interventions. Important considerations include cost, public opinion regarding the conduct of animal research, translational value, and relevance of the animal model for clinical practice. We present an overview of two porcine models of organ donation: donation following brain death (DBD) and donation following circulatory death (DCD). The cardiovascular anatomy and physiology of pigs closely resembles those of humans, making this species the most appropriate for pre-clinical research. Pigs are also considered a potential source of organs for human heart and kidney xenotransplantation. It is imperative to minimize animal loss during procedures that are surgically complex. We present our experience with these models and describe in detail the use cases, procedural approach, challenges, alternatives, and limitations of each model.

Cardiac function unchanged following reanimation with normothermic regional perfusion in donation after circulatory death.

Objectives: To determine whether hearts reanimated with normothermic regional perfusion (NRP) have clinically detectable changes in function using echocardiography comparing the prearrest and post-NRP imaging. As heart transplantation from donation after circulatory death (DCD) continues to increase, preliminary results suggest outcomes comparable with donation after brain death. It is unknown whether the obligatory period of warm ischemia experienced during DCD withdrawal process causes immediate changes in cardiac allograft function following in situ reanimation. Methods: We retrospectively reviewed and compared predonation with postreanimation echocardiographic findings in all DCD donors at our institution from January to October 2021. All DCD donor organs were reanimated with in situ thoracoabdominal NRP after circulatory death. Echocardiographic assessment included (1) 2-dimensional and speckle-tracking measures of chamber size and function; (2) ejection fraction; (3) fractional area change; and (4) global longitudinal strain. Results: Altogether, 4 DCD heart donations were performed during the study period. Basic demographics and withdrawal ischemic time periods are reported. There were no changes in left ventricular ejection fraction and right ventricular fractional area change when comparing the predonation and the postreanimation echocardiogram. There was a minimal, nonstatistically significant decrease in left ventricular global longitudinal strain and right ventricular free-wall systolic strain in 3 of the 4 donors following reanimation. Conclusions: DCD cardiac allografts reanimated with NRP demonstrated no change in echocardiographic parameters used for a standard predonation donor heart evaluation. Findings suggest cardiac function of DCD allografts reanimated with thoracoabdominal NRP is not adversely impacted by limited period of warm ischemia following circulatory arrest.

Thoracoabdominal Normothermic Perfusion in Donation After Circulatory Death.

Donation after circulatory death is emerging as an alternative pathway to donation after brain death to expand the cardiac organ donor pool. We describe the surgical technique and circuit configuration for in-situ organ reperfusion with thoracoabdominal normothermic regional perfusion using portable venoarterial extracorporeal membrane oxygenation.

Zero balance ultrafiltration using dialysate during nationwide bicarbonate shortage: a retrospective analysis.

BACKGROUND: Zero balance ultrafiltration (Z-BUF) utilizing injectable 8.4% sodium bicarbonate is utilized to treat hyperkalemia and metabolic acidosis associated with cardiopulmonary bypass (CPB). The nationwide shortage of injectable 8.4% sodium bicarbonate in 2017 created a predicament for the care of cardiac surgery patients. Given the uncertainty of availability of sodium bicarbonate solutions, our center pro-actively sought a solution to the sodium bicarbonate shortage by performing Z-BUF with dialysate (Z-BUF-D) replacement fluid for patients undergoing cardiopulmonary bypass. METHODS: Single-center, retrospective observational evaluation of the first 46 patients at an academic medical center who underwent Z-BUF using dialysate over a period of 150 days with comparison of these findings to a historical group of 39 patients who underwent Z-BUF with sodium chloride (Z-BUF-S) over the preceding 150 days. The primary outcome was the change in whole blood potassium levels pre- and post-Z-BUF-D. Secondary outcomes included changes in pre- and post-Z-BUF-D serum bicarbonate levels and the amount of serum bicarbonate used in each Z-BUF cohort (Z-BUF-D and Z-BUF-S). RESULTS: Z-BUF-D and Z-BUF-S both significantly reduced potassium levels during CPB. However, Z-BUF-D resulted in a significantly decreased need for supplemental 8.4% sodium bicarbonate administration during CPB (52 mEq ± 48 vs. 159 mEq ± 85, P < 0.01). There were no complications directly attributed to the Z-BUF procedure. CONCLUSION: Z-BUF with dialysate appears to be analternative to Z-BUF with sodium chloride with marked lower utilization of intravenous sodium bicarbonate.