Background. The ideal preservation temperature for donation after circulatory death kidney grafts is unknown. We investigated whether subnormothermic (22 °C) ex vivo kidney machine perfusion could improve kidney metabolism and reduce ischemia-reperfusion injury. Methods. To mimic donation after circulatory death procurement, kidneys from 45-kg pigs underwent 60 min of warm ischemia. Kidneys were then perfused ex vivo for 4 h with Belzer machine perfusion solution UW at 22 °C or at 4 °C before transplantation. Magnetic resonance spectroscopic imaging coupled with LCModel fitting was used to assess energy metabolites. Kidney perfusion was evaluated with dynamic-contrast enhanced MRI. Renal biopsies were collected at various time points for histopathologic analysis. Results. Total adenosine triphosphate content was 4 times higher during ex vivo perfusion at 22 °C than at 4 °C perfusion. At 22 °C, adenosine triphosphate levels increased during the first hours of perfusion but declined afterward. Similarly, phosphomonoesters, containing adenosine monophosphate, were increased at 22 °C and then slowly consumed over time. Compared with 4 °C, ex vivo perfusion at 22 °C improved cortical and medullary perfusion. Finally, kidney perfusion at 22 °C reduced histological lesions after transplantation (injury score: 22 °C: 10.5 ± 3.5; 4 °C: 18 ± 2.25 over 30). Conclusions. Ex vivo kidney perfusion at 22°C improved graft metabolism and protected from ischemia-reperfusion injuries upon transplantation. Future clinical studies will need to define the benefits of subnormothermic perfusion in improving kidney graft function and patient’s survival.
Background: The COVID-19 (coronavirus disease 2019) pandemic is reducing health care accessibility to non–life-threatening diseases, thus hiding their real incidence. Moreover, the incidence of potentially fatal conditions such as acute type A aortic dissection seems to have decreased since the pandemic began, whereas the number of cases of chronic ascending aortic dissections dramatically increased. We present two patients whose management has been affected by the exceptional sanitary situation we are dealing with.Case report: A 70-year-old man with chest pain and an aortic regurgitation murmur had his cardiac workup delayed (4 months) because of sanitary restrictions. He was then diagnosed with chronic type A aortic dissection and underwent urgent replacement of ascending aorta and aortic root. The delay in surgical treatment made the intervention technically challenging because the ascending aorta grew up to 80 mm inducing strong adhesions and chronic inflammation. The second case report concerns a 68-year-old woman with right lower-limb pain who was diagnosed with deep vein thrombosis. However, a CT scan to exclude a pulmonary embolism could not be realized until 5 months later because of sanitary restrictions. When she eventually got the CT scan, it fortuitously showed a chronic dissection of the ascending aorta. She underwent urgent surgery, and the intervention was challenging because of adhesions and severe inflammation.Conclusion: Delayed treatment due to sanitary restrictions related to COVID-19 pandemic is having a significant impact on the management of potentially life-threatening conditions including type A aortic dissection. We should remain careful to avoid COVID-19 also hitting patients who are not infected with the virus.
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