Keeping It Cool: Extended Myocardial Protection with Topical Cooling to Reduce PGD

Abstract

Purpose Around 2000 heart transplants are performed in Europe annually. Primary Graft Dysfunction(PGD) rates in Europe are among the highest in the world. The increasing use of marginal donor organs has been suggested as a potential cause. Novel techniques using ex-vivo normothermic perfusion have garnered increasing interest but incur a significant cost. We present a series of patients who underwent heart transplantation at our unit using a novel implantation technique to reduce PGD that is cost-effective and reproducible Methods The donor heart is removed from cold storage and placed in an ice slush basin on arrival to our unit. An aortic cross clamp is applied distal to the donor ascending aorta. An antegrade infusion of 600mls of cold blood cardioplegia is followed by cold oxygenated blood (4-6°C) to achieve a mean aortic root pressure of 60-70 mmHg. This continuous antegrade perfusion is maintained throughout the left atrium and aortic anastomosis with a left ventricular vent in situ. A warm cardioplegia hotshot is infused into the aortic root prior to removal of the recipient aortic cross-clamp. The remaining anastomoses are carried out in the usual fashion sequentially. We compared our experience with this method with the national UK cohort (2015-2016) of patients (Control Group). We performed multivariable logistic regression comparing the two cohorts with PGD as the primary outcome measure. Confounders adjusted for include donor age, recipient age and donor-recipient gender mismatch. Results 139 (71.6 %) patients were male. 46(18.6%) of the patients had ischemic cardiomyopathy. The odds ratio of PGD in the control group was 2.99 (95% CI 1.02- 8.75) when compared to the Extended Cooling. Conclusion This novel approach is associated with significant reductions in PGD rates post-transplantation likely due to the shorter warm ischemic time. Larger studies are needed to show differences after further adjustment for known confounders of PGD. We believe this novel technique is safe, cost-effective and reproducible. Around 2000 heart transplants are performed in Europe annually. Primary Graft Dysfunction(PGD) rates in Europe are among the highest in the world. The increasing use of marginal donor organs has been suggested as a potential cause. Novel techniques using ex-vivo normothermic perfusion have garnered increasing interest but incur a significant cost. We present a series of patients who underwent heart transplantation at our unit using a novel implantation technique to reduce PGD that is cost-effective and reproducible The donor heart is removed from cold storage and placed in an ice slush basin on arrival to our unit. An aortic cross clamp is applied distal to the donor ascending aorta. An antegrade infusion of 600mls of cold blood cardioplegia is followed by cold oxygenated blood (4-6°C) to achieve a mean aortic root pressure of 60-70 mmHg. This continuous antegrade perfusion is maintained throughout the left atrium and aortic anastomosis with a left ventricular vent in situ. A warm cardioplegia hotshot is infused into the aortic root prior to removal of the recipient aortic cross-clamp. The remaining anastomoses are carried out in the usual fashion sequentially. We compared our experience with this method with the national UK cohort (2015-2016) of patients (Control Group). We performed multivariable logistic regression comparing the two cohorts with PGD as the primary outcome measure. Confounders adjusted for include donor age, recipient age and donor-recipient gender mismatch. 139 (71.6 %) patients were male. 46(18.6%) of the patients had ischemic cardiomyopathy. The odds ratio of PGD in the control group was 2.99 (95% CI 1.02- 8.75) when compared to the Extended Cooling. This novel approach is associated with significant reductions in PGD rates post-transplantation likely due to the shorter warm ischemic time. Larger studies are needed to show differences after further adjustment for known confounders of PGD. We believe this novel technique is safe, cost-effective and reproducible.