Oxygenated machine perfusion at room temperature as an alternative for static cold storage in porcine donor hearts

Background There is a continued interest in ex situ heart perfusion as an alternative strategy for donor heart preservation. We hypothesize that oxygenated machine perfusion of donor hearts at a temperature that avoids both normothermia and deep hypothermia offers adequate and safe preservation. Methods Cardioplegia-arrested porcine donor hearts were randomly assigned to six hours of preservation using cold storage (CS, n = 5) or machine perfusion using an oxygenated acellular perfusate at 21 degrees C (MP, n = 5). Subsequently, all grafts were evaluated using the Langendorff method for 120 min. Metabolic parameters and histology were analyzed. Systolic function was assessed by contractility and elastance. Diastolic function was assessed by lusitropy and stiffness. Results For both groups, in vivo baseline and post-Langendorff biopsies were comparable, as were lactate difference and myocardial oxygen consumption. Injury markers gradually increased and were comparable. Significant weight gain was seen in MP (p = 0.008). Diastolic function was not impaired in MP, and lusitropy was superior from 30 min up to 90 min of reperfusion. Contractility was superior in MP during the first hour of evaluation. Conclusion We conclude that the initial functional outcome of MP-preserved hearts was transiently superior compared to CS, with no histological injury post-Langendorff. Our machine perfusion strategy could offer feasible and safe storage of hearts prior to transplantation. Future studies are warranted for further optimization

Oxygenated machine perfusion at room temperature as an alternative for static cold storage in porcine donor hearts

Background There is a continued interest in ex situ heart perfusion as an alternative strategy for donor heart preservation. We hypothesize that oxygenated machine perfusion of donor hearts at a temperature that avoids both normothermia and deep hypothermia offers adequate and safe preservation. Methods Cardioplegia-arrested porcine donor hearts were randomly assigned to six hours of preservation using cold storage (CS, n = 5) or machine perfusion using an oxygenated acellular perfusate at 21 degrees C (MP, n = 5). Subsequently, all grafts were evaluated using the Langendorff method for 120 min. Metabolic parameters and histology were analyzed. Systolic function was assessed by contractility and elastance. Diastolic function was assessed by lusitropy and stiffness. Results For both groups, in vivo baseline and post-Langendorff biopsies were comparable, as were lactate difference and myocardial oxygen consumption. Injury markers gradually increased and were comparable. Significant weight gain was seen in MP (p = 0.008). Diastolic function was not impaired in MP, and lusitropy was superior from 30 min up to 90 min of reperfusion. Contractility was superior in MP during the first hour of evaluation. Conclusion We conclude that the initial functional outcome of MP-preserved hearts was transiently superior compared to CS, with no histological injury post-Langendorff. Our machine perfusion strategy could offer feasible and safe storage of hearts prior to transplantation. Future studies are warranted for further optimization.</p

The role of transesophageal echocardiography in guiding heart donation after circulatory death.

peer reviewedHeart donation after circulatory death (DCD) can significantly expand the heart donor pool, helping to overcome the problem of organ shortage and the increase in waiting list mortality and morbidity. To improve the outcome of DCD heart transplantation, thoraco-abdominal normothermic regional perfusion (TA-NRP) can be performed by selectively restoring circulation followed by in vivo functional heart assessment. Here, we report on the use of periprocedural transoesophageal echocardiography (TOE) as a minimally invasive cardiac assessment tool during different stages of a DCD heart procurement procedure using TA-NRP. We conclude that TOE is a valuable method to assess the donor heart for transplantation eligibility before and after withdrawal of life-sustaining therapy and during subsequent TA-NRP

Individually tailored training to improve less invasive coronary surgery

Background: Minimal invasive coronary surgery has been criticized for being unsafe and lack of dispersion. To allow an individually tailored training and improve dispersion, training models and self-evaluation are needed. We wanted to build a realistic beating heart model and scoring system to allow a surgeon to evaluate his skills and limitations in minimal invasive coronary surgery and to use it at training model for both Off Pump Coronary Artery Bypass Surgery (OPCAB) and Minimal Invasive Direct Coronary Artery Bypass Surgery (MIDCAB) procedures. Methods: We used a beating heart model (CABG HEARTS #1259, The Chamberlain group, Great Barrington, MA, USA) and installed it in a dedicated box or skeleton to mimic the spatial limitations in OPCAB and MIDCAB. 5 fellows and 5 residents were enrolled and trained single coronary anastomosis with beating heart techniques. Pig ureters were used as grafts, and plastic tubes (1.75mm) were used as target vessels. Before and after the training, subjects were evaluated for anastomotic time, leakage, shape, flow measurement and personal appreciation of their work. Each aspect has a score from 1 to 5 points (full marks; 25points) and total scores were calculated afterwards. The significance was evaluated using Wilcoxon rank sum test and the Mann-Whitney test. Results: In all 10 cases, median score increased significantly from 15.5[12-18] to 18.5[17-20], P=0.03. Total score was different between fellows and residents pre-exercise (12vs18, P=0.01), but no longer after 3 initial training sessions (17vs19, P=0.29). Anastomosis times decreased significantly in the resident group (27min to 18min, P=0.05) but not in fellow group (14min to 18min, P=0.59). Evaluating only the objective parameters by an observer confirms the rapid learning in residents, but plateau phase in the already more skilled fellows. Conclusions: With this beating heart anastomosis model we can evaluate pre-training skills and improve test scores by incremental learning. In young residents this increases their performance quickly to a level of fellow trainees. Subsequently, the more experienced fellow can continue to use it in a more challenging minimal invasive environment to continuously further improve their anastomotic skills.status: accepte

Mechano-biological adaptation of the pulmonary artery exposed to systemic conditions

Cardiac surgeries may expose pulmonary arterial tissue to systemic conditions, potentially resulting in failure of that tissue. Our goal was to quantitatively assess pulmonary artery adaptation due to changes in mechanical environment. In 17 sheep, we placed a pulmonary autograft in aortic position, with or without macroporous mesh reinforcement. It was exposed to systemic conditions for 6 months. All sheep underwent 3 ECG-gated MRI’s. Explanted tissue was subjected to mechanical and histological analysis. Results showed progressive dilatation of the unreinforced autograft, while reinforced autografts stabilized after two months. Some unreinforced pulmonary autograft samples displayed more aorta-like mechanical behavior with increased collagen deposition. The mechanical behavior of reinforced autografts was dominated by the mesh. The decrease in media thickness and loss of vascular smooth muscle cells was more pronounced in reinforced than in unreinforced autografts. In conclusion, altering the mechanical environment of a pulmonary artery causes changes in its mechano-biological properties.status: publishe