Alveolar expansion itself but not continuous oxygen supply enhances postmortem preservation of pulmonary grafts

Abstract Objective: If lungs could be retrieved for transplant after circulatory arrest, the shortage of donors might be significantly alleviated. Great controversy still exists concerning the optimal mode of preservation of pulmonary grafts in these non-heart-beating donors. Methods: Graft function was measured in an isolated room air-ventilated rabbit lung model during reperfusion with homologous, diluted (Hb 9 8.0 g/dl) and deoxygenated (PaO 2 9 40 mmHg) blood up to 4 h. Five groups of cadavers (n =4 in each group) were studied: In the control group, lungs were immediately reperfused. In the other groups, cadavers were left at room temperature for 4 h after death with lungs either deflated (group 1), inflated with room air (group 2), or ventilated with room air (group 3) or 100% nitrogen (group 4). Results: After 1 h of reperfusion, significant differences were noted between group 1 and groups 2, 3, and 4 in peak airway pressure (27 95 cm H 2 0 vs. 15 9 1 cm H 2 0, 17 9 2 cm H 2 0, and 16 91 cm H 2 0, respectively; PB 0.05), in weight gain (137 9 24 vs. 31 9 7, 30 9 3, and 30 9 2%, respectively; PB 0.05), and in veno-arterial oxygen pressure gradient (9 9 5 vs. 95 913, 96 97 and 96 9 4 mmHg, respectively; PB 0.05). Also, wet-to-dry weight ratio at end of reperfusion was significantly different (10.29 1.0 vs. 6.09 0.3, 5.29 0.3 and 5.49 0.5, respectively; PB 0.05). No significant differences in any of these parameters were observed between groups 2, 3, and 4. Conclusions: These data suggest that: (1) pulmonary edema will develop in atelectatic lungs if reperfusion is delayed for 4 h after death; (2) postmortem room air-inflation is as good as ventilation in prolonging warm ischemic tolerance; (3) ventilation with room air is no different from that with nitrogen; (4) therefore, prevention of alveolar collapse appears to be the critical factor in protecting the warm ischemic lung from reperfusion injury independent of continuous oxygen supply

Aortic valve replacement and concomitant procedures with the Perceval valve: results of European trials.

BACKGROUND The Perceval (Sorin Group, Milan, Italy) is a self-anchoring sutureless aortic valve prosthesis. We report the short- to midterm results of combined aortic valve replacement (AVR) with concomitant procedures in elderly patients undergoing operation as part of 3 consecutive prospective multicenter European studies. METHODS From April 2007 to February 2013, 243 patients (mean age, 79.7 ± 5.1 years; female patients, 61%; median EuroSCORE, 9%) underwent AVR with concomitant procedures. The concomitant procedures were coronary artery bypass grafting (CABG) (182 cases), septal myectomy (21 cases), CABG + other procedures (18 cases), and 22 other procedures. Primary and secondary end points included implant feasibility and safety (for mortality and morbidity) and efficacy (New York Heart Association [NYHA] class improvement and hemodynamic results) of the prosthesis at the different follow-up periods. Data were expressed as mean ± standard deviation. Kaplan-Meier analysis was performed for survival analysis. RESULTS Mean aortic cross-clamp and extracorporeal circulation (ECC) times were 50.7 ± 22.8 minutes and 78.9 ± 32.3 minutes, respectively. Thirty-day mortality was 2.1%. Mean postoperative gradient and effective orifice area were 10.1 ± 4.7 mm Hg and 1.5 ± 0.4 cm(2) and 8.9 ± 5.6 mm Hg and 1.6 ± 0.4 cm(2), respectively, at 1 year. There were early explantations, 4 of which resulted from paravalvular leaks. One additional valve explantation resulted from aortic root bleeding, probably caused by excessively extensive decalcification. In the late period, there was 1 mild paravalvular leak and no intravalvular insufficiency. No migration, dislodgement, or degeneration of the valve occurred during follow-up. Median follow-up was 444 days. CONCLUSIONS These trials confirm the safety and efficacy of the Perceval sutureless aortic valve, especially in elderly patients requiring AVR + concomitant procedures. In this patient group, sutureless valves may be advantageous compared to transcatheter valve implantations as concomitant procedures other than percutaneous coronary artery angioplasty are not always possible in the latter

Chronic haemodynamic performance of a biorestorative transcatheter heart valve in an ovine model

Background: The Xeltis biorestorative transcatheter heart valve (BTHV) leaflets are made from an electrospun bioabsorbable supramolecular polycarbonate-urethane and are mounted on a self-expanding nitinol frame. The acute haemodynamic performance of this BTHV was favourable. Aims: We sought to demonstrate the preclinical feasibility of a novel BTHV by evaluating the haemodynamic performances of five pilot valve designs up to 12 months in a chronic ovine model. Methods: Five design iterations (A, B, B', C, and D) of the BTHV were transapically implanted in 46 sheep; chronic data were available in 39 animals. Assessments were performed at implantation, 3, 6, and 12 months including quantitative aortography, echocardiography, and histology. Results: At 12 months, greater than or equal to moderate AR on echocardiography was seen in 0%, 100%, 33.3%, 100%, and 0% in the iterations A, B, B', C, and D, respectively. Furthermore, transprosthetic mean gradients on echocardiography were 10.0±2.8 mmHg, 19.0±1.0 mmHg, 8.0±1.7 mmHg, 26.8±2.4 mmHg, and 11.2±4.1 mmHg, and effective orifice area was 0.7±0.3 cm2, 1.1±0.3 cm2, 1.5±1.0 cm2, 1.5±0.6 cm2, and 1.0±0.4 cm2 in the iterations A, B, B', C, and D, respectively. On pathological evaluation, the iteration D demonstrated generally intact leaflets and advanced tissue coverage, while different degrees of structural deterioration were observed in the other design iterations. Conclusions: Several leaflet material iterations were compared for the potential to demonstrate endogenous tissue restoration in an aortic valve in vivo. The most promising iteration showed intact leaflets and acceptable haemodynamic performance at 12 months, illustrating the potential of the BTHV