Degenerative processes in bioprosthetic mitral valves in juvenile pigs

Abstract Background Glutaraldehyde-treated bioprosthetic heart valves are commonly used for replacement of diseased heart valves. However, calcification and wear limit their durability, and the development of new and improved bioprosthetic valve designs is needed and must be evaluated in a reliable animal model. We studied glutaraldehyde-treated valves 6 months after implantation to evaluate bioprosthetic valve complications in the mitral position in juvenile pigs. Materials The study material comprised eight, 5-month old, 60-kg pigs. All pigs received a size 27, glutaraldehyde-treated, stented, Carpentier-Edwards S.A.V. mitral valve prosthesis. After six months, echocardiography was performed, and the valves explanted for gross examination, high resolution X-ray, and histological evaluation. Results Five pigs survived the follow-up period. Preexplant echocardiography revealed a median peak and mean velocity of 1.61 m/s (range: 1.17-2.00) and 1.20 (SD = ±0.25), respectively, and a median peak and mean pressure difference of 10.42 mmHg (range: 5.83-16.55) and 6.51 mmHg (SD = ±2.57), respectively. Gross examination showed minor thrombotic depositions at two commissures in two valves and at all three commissures in three valves. High resolution X-ray imaging revealed different degrees of calcification in all explanted valves, primarily in the commissural and belly areas. In all valves, histological evaluation demonstrated various degrees of fibrous sheath formation, limited immunological infiltration, and no overgrowth of host endothelium. Conclusions Bioprosthetic glutaraldehyde-treated mitral valves can be implanted into the mitral position in pigs and function after 6 months. Echocardiographic data, calcification, and histological examinations were comparable to results obtained in sheep models and human demonstrating the suitability of the porcine model.</p

Perioperative lipid-enriched enteral nutrition versus standard care in patients undergoing elective colorectal surgery (SANICS II):a multicentre, double-blind, randomised controlled trial

Postoperative ileus and anastomotic leakage severely impair recovery after colorectal resection. We investigated the effect of perioperative lipid-enriched enteral nutrition versus standard care on the risk of postoperative ileus, anastomotic leakage, and other clinical outcomes. We did an international, multicentre, double-blind, randomised, controlled trial of patients (≥18 years) undergoing elective colorectal surgery with primary anastomosis at six clinical centres in the Netherlands and Denmark. Patients were randomly assigned (1:1), stratified by location (colonic and rectal) and type of surgery (laparoscopic and open), via online randomisation software, with block sizes of six, to receive either continuous lipid-enriched enteral tube feeding from 3 h before until 6 h after surgery (intervention) or no perioperative nutrition (control). Surgeons, patients, and researchers were masked to treatment allocation for the entire study period. The primary outcome was postoperative ileus. Secondary outcomes included anastomotic leakage, pneumonia, preoperative gastric volumes, time to functional recovery, length of hospital stay, the need for additional interventions, intensive care unit admission, postoperative inflammatory response, and surgical complications. Analyses were by intention to treat. This study is registered with ClinicalTrials.gov, number NCT02175979, and trialregister.nl, number NTR4670. Between July 28, 2014, and February 20, 2017, 280 patients were randomly assigned, 15 of whom were excluded after random allocation because they fulfilled one or more exclusion criteria. 265 patients received perioperative nutrition (n=132) or standard care (n=133) and were included in the analyses. A postoperative ileus occurred in 37 (28%) patients in the intervention group versus 29 (22%) in the control group (risk ratio [RR] 1·09, 95% CI 0·95-1·25; p=0·24). Anastomotic leakage occurred in 12 (9%) patients in the intervention group versus 11 (8%) in the control group (RR 1·01, 95% CI 0·94-1·09; p=0·81). Pneumonia occurred in ten (8%) patients in the intervention group versus three (2%) in the control group (RR 1·06, 95% CI 1·00-1·12; p=0·051). All other secondary outcomes were similar between groups (all p>0·05). Perioperative lipid-enriched enteral nutrition in patients undergoing elective colorectal surgery has no advantage over standard care in terms of postoperative complications. Netherlands Organisation for Health Research and Development (ZonMW), Fonds NutsOhra, and Danone Researc