Despite variable functional outcomes, third and fourth kidney transplant recipients experience comparable patient survival rates to first and second transplants, regardless of the donor type. In selected patients, HLA-incompatible live donors and extended-criteria deceased-donors should be considered.

A best-evidence topic in vascular surgery was written according to a structured protocol. The question addressed was whether screening asymptomatic individuals for an abdominal aortic aneurysm (AAA) is feasible and improves disease-free survival. Seven studies presented the best evidence to answer the clinical question. The author, journal, date and country of publication, patient group studied, study type, relevant outcomes, results and limitations of the studies are tabulated. In total, four randomized population-based studies have evaluated ultrasound screening for AAA: two British studies, Multicentre Aneurysm Screening Study (MASS) and the Chichester trial, and one each in Viborg County, Denmark and Western Australia. Participants were randomized to receive an invitation to screen or not. The MASS trial randomized 67 770 men, followed participants over 10 years and concluded that screening would almost half AAA-related deaths in men aged 65-74 years. The smaller Chichester trial included only 6040 men but demonstrated a 42% reduction in AAA-related mortality at 5 years, with ongoing benefit at 15 years (11% reduction). The Viborg County trial recruited 12 639 men aged 64-73 years, showed a 66% reduction in AAA-related mortality over 14 years. Finally, the Western Australia trial evaluated 41 000 men but included an older population of 65-83 years old. No benefit was seen in this age group but subgroup analysis of men aged 65-74 showed a significant mortality benefit. Only a small or insignificant benefit in all-cause mortality was seen in any of these studies. A recent meta-analysis of these trials has shown a significant benefit in AAA-related mortality in the long term and concluded that AAA screening is superior to other established screening programmes. The cost-effectiveness of screening was assessed in the MASS and Viborg County trials and was found to be substantially below the cost threshold set by the National Institute of Clinical Excellence for acceptance of interventions. Quality of life was assessed in the MASS and in a case-control study and showed no adverse effects that outweigh the benefits. We concluded that ultrasound screening for AAAs has met all the criteria to become a screening programme and would substantially reduce disease-related death with no adverse effect on quality of life.

Introduction:Recent experimental evidence suggests normothermic machine perfusion of the vascularized composite allograft results in improved preservation compared to static cold storage, with less reperfusion injury in the immediate post-operative period. However, metabolic acidosis is a common feature of vascularized composite allograft perfusion, primarily due to the inability to process metabolic by-products. We evaluated the impact of combined limb-kidney perfusion on markers of metabolic acidosis and inflammation in a porcine model. Methods:Ten paired pig forelimbs were used for this study, grouped as either limb-only (LO, n = 5) perfusion, or limb-kidney (LK, n = 5) perfusion. Infrared thermal imaging was used to determine homogeneity of perfusion. Lactate, bicarbonate, base, pH, and electrolytes, along with an inflammatory profile generated via the quantification of cytokines and cell-free DNA in the perfusate were recorded. Results:The addition of a kidney to a limb perfusion circuit resulted in the rapid stabilization of lactate, bicarbonate, base, and pH. Conversely, the LO This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

A best evidence topic in cardiovascular surgery was written according to a structured protocol. The question addressed was whether administering sodium bicarbonate (NaHCO3) prevents contrast-induced nephropathy (CIN) in cardiovascular patients undergoing contrast imaging. In total, 266 papers were found using the reported search, 16 of which represented the best evidence to answer the clinical question. The authors, journal, date and country of publication, patient group studied, study type, relevant outcomes and results of these papers are tabulated. CIN is thought to occur as a result of ischaemic or oxidative injury to the kidney. It is postulated that NaHCO3attenuates this renal damage by alkanizing renal tubular fluid thus reducing the generation of contrast-induced free radicals, which damage the kidney. Of the 16 trials, 15 recruited patients with various degrees of renal dysfunction at baseline. The benefit of using NaHCO3 was demonstrated at all stages of chronic kidney disease. Apart from four studies, 12 studies used low toxicity, low-osmolar contrast. Merten et al. published the first trial of NaHCO3 vs (saline) NaCl in preventing CIN, demonstrated a significantly lower rate in the NaHCO3 group and advocated its widespread use. Subsequent trials using the same regimen have collaborated these results. However, more recently, Gomes et al. concluded that NaHCO3 is not superior to saline-based hydration. Similarly, Brar et al. randomized 323 patients with moderate-to-severe renal insufficiency to receive either an NaHCO3 or an NaCl infusion and observed no difference in CIN rates. Two studies investigated the effects of rapid urine alkanization with bolus injections of NaHCO3 prior to contrast and found significant reductions in CIN rates compared with NaCl-treated groups. One study observed that NaCl is superior to NaHCO3, while all other studies showed a beneficial effect or no difference between NaCl- and NaHCO3-based hydration. The most recent meta-analysis by Jang et al. incorporated 3609 patients across 19 trials and concluded that NaHCO3-based hydration regimens are superior to NaCl-based ones. Based on this review, the authors recommend NaHCO3 alongside an NaCl hydration regimen. The exact regimen will depend on the context within which contrast is being administered and needs further evaluation.

The American Transplant Congress 2022, which took place between June 4th and June 8th of 2022, was a hybrid meeting with in‐person attendance in Boston‐MA and a real‐time virtual experience via an online platform. First, we identified abstracts discussing machine perfusion preservation for all organs, a hot topic and approach that may develop into the new gold standard of organ preservation in the near future. A total of 39 abstracts on organ machine preservation were presented at the meeting. Next, we selected abstracts which focus on advances including new approaches to organ preservation, promising biomarkers, ex‐situ treatment including cellular therapies, and novel research areas. Here, we summarized the latest developments on machine perfusion preservation in both experimental and clinical studies.