Progressive gastric perfusion in rats: Role of ischemic conditioning

Abstract

Occult ischemia of the mobilized stomach is usually related to the dehiscence of an esophagogastric anastomosis. The principle of ischemic conditioning was studied to verify its clinic use. This study aims to evaluate progressively the tissue perfusion of the stomach in ischemic conditioning, establishing the best moment for gastric transposition. Twenty-four male EPM-1 Wistar rats were used, which also underwent partial desvacularization of the stomach by ligature of the left gastric vessels. Tissue perfusion was measured through flowmetry by laser Doppler (tissue perfusion unit; TPU) in the antrum (10 mm distal from the cardiac region). This measurement was done before (baseline) and immediately after the ligature, and on different postoperative days (POD) (days 3, 7, 10, and 14). A statistical analysis was done with nonparametric tests (P <or= 0.05). The mean value (+/-SD) of the gastric perfusion, during the whole study period, was 88 +/- 6 (baseline), 23 +/- 5 (postligature), 31 +/- 5 (3rd POD), 55 +/- 4 (7th POD), 71 +/- 16 (10th POD), and 84 +/- 6 (14th POD), respectively. Perfusion immediately after the artery ligature was significantly lower (74%) than the baseline of the gastric perfusion; therefore, in the following days, tissue perfusion increased progressively (35%, 63%, 81%, and 96%, respectively). The flowmetry of the stomach reached basal values in the 14th POD of desvascularization, suggesting that this would the best day to perform a gastric transposition. However, on the 10th POD, good tissue perfusion was observed. The extrapolation from these data to the clinic could improve the results of esophagogastric anastomosis.

Ischemic conditioning shows a time-dependant influence on the fate of the gastric conduit after minimally invasive esophagectomy

“…Numerous animal experiments have pondered the merits of gastric ischemic conditioning [17][18][19][20], most notably the work by Urschel [43], and more recently, the work of Lamas et al [21].…”

“…The technique, described elsewhere [19], involves a thoracoscopic esophageal mobilization with mediastinal lymphadenectomy followed by a laparoscopic gastric mobilization and conduit formation with radical lymphadenectomy and finally a resection and cervical anastomosis.…”

“…The discovery of the ''delay phenomenon'' in plastic surgery, whereby a graft is rendered ischemic before translocation to increase its eventual vascularity through the dilation of choke vessels [16], is recognized as having potential benefit for the gastric conduit [17]. Further animal studies by Urschel et al [18], Alfabet et al [19], Reavis et al [20], and more recently, Lamas et al [21] have shown a potential benefit.…”

Modelo videolaparoscópico de condicionamento isquêmico do estômago em ratos

“…This better perfusion may be due not only to new vascularization that would occur as a response to continual tissue ischemia, but also to the alteration in the blood flow of the microcirculation promoted by denervation 15 and the vascularization resulting from the scarring process itself 16 . In our laboratory, Alfabet et al 3 made a study of the functioning of the gastric wall at different postoperative times and showed a recovery of tissue perfusion from the seventh day onwards and a return to base levels on the tenth day. The animal model chosen was the rat, which has been proposed by several authors who have shown this to be an experimentation animal that is suitable for the study of ischemic conditioning, and also for accomplishing research on video-surgery 17,18 .…”

“…This phenomenon was named ischemic conditioning of the stomach. Alfabet et al 3 evaluated laser-Doppler flowmetry in the gastric wall of rats at various times subsequent to ligature of the left gastric vessels. They showed that the blood flow returned to base levels after 10 days.…”