Utilization of the delay phenomenon improves blood flow and reduces collagen deposition in esophagogastric anastomoses

Complications of anastomotic healing are a common source of morbidity and mortality after esophagogastrostomy. The delay phenomenon is seen when a skin flap is partially devascularized in a staged procedure prior to its definitive placement, resulting in increased blood flow at the time of grafting. This effect may be applied to esophagogastrectomy, potentially reducing anastomotic complications. The purpose of this investigation was to apply the delay principle to the gastrointestinal tract, investigate mechanisms by which it occurs and examine the effects of delay on anastomotic healing. Thirty-seven opossums were assigned to Sham (n = 5), Immediate (n = 14), and Delay (n = 18) groups. Each underwent laparotomy and measurement of baseline gastric fundus blood flow. The Delay and Immediate animals underwent ligation of the left, right, and short gastric vessels and subsequent measurement of gastric fundus blood flow. The Delay group underwent repeat measurement of blood flow, esophagogastrectomy, gastric tubularization, and esophagogastrostomy 28 days after vessel ligation. The Immediate group completed the procedure immediately after vessel ligation. The anastomoses in both groups were harvested 32 days after esophagogastrostomy. The Sham group underwent blood flow measurement on initial laparotomy, followed by harvesting of esophagogastric junction 60 days later. Sections taken through the anastomoses were examined with trichrome-staining and immunohistochemistry (IHC) for actin. Collagen content of the gastric submucosa 5 mm below the anastomosis was quantified, and preservation of the muscularis propria and muscularis mucosa was determined histologically. Capillary content of the esophagogastric junction was quantified using IHC for vascular endothelium in the Delay and Sham groups. Blood flow decreased by 73% following vessel ligation in Delay and Immediate groups. The Delay group had over 3 times the gastric blood flow of the Immediate group at the time of anastomosis at 16 (interquartile range [IQR] 11-17) versus 5, (IQR 5-6) mL/min/100 g (P = 0.000003). Two Immediate animals developed anastomotic leak and died; the Delay group had no complications. Submucosal collagen content in Sham, Delay, and Immediate groups were 57% (IQR 52-62), 65% (IQR 57-72), and 71% (IQR 60-82), respectively (P = 0.0004). The median distance of full-thickness atrophy of the muscularis propria was 0.10 mm (IQR 0-0.60 mm) in the Delay group and 0.53 mm (IQR 0.03-0.80 mm) in