SEQUENCE OF MORPHOLOGICAL AND HEMODYNAMIC-CHANGES OF GASTRIC MICROVESSELS IN PORTAL-HYPERTENSION

Changes in gastric microvasculature and blood flow at different phases of portal hypertension were studied in rats 1, 2, 3, 4, and 15 days after induction of portal hypertension or sham operation. Vessel lumen and vessel wall thickness were expressed as a ratio referred to the vessel size. On day 2 after constriction of the portal vein, gastric blood flow was decreased (0.57 ± 0.06 vs. 0.99 ± 0.20 mL · min-1 · 100 g-1; P < 0.05), and gastric vessels had a distended lumen (0.42 ± 0.02 vs. 0.28 ± 0.03; P < 0.01) and a thin wall (2.11 ± 0.2 vs. 3.82 ± 0.4; P < 0.01). On day 4, the gastric blood flow of portal hypertensive animals was increased (1.15 ± 0.14 vs. 0.71 ± 0.07 mL · min-1 · 100 g-1; P < 0.05), whereas gastric vessels had a reduced lumen (0.27 ± 0.02 vs. 0.33 ± 0.02; P < 0.01) and a thick wall (4.19 ± 0.52 vs. 3.16 ± 0.30; P < 0.05). By day 15, vessels with the largest lumens (0.45 ± 0.01 vs. 0.29 ± 0.01; P < 0.01) and the thinnest walls (1.78 ± 0.26 vs. 3.58 ± 0.62; P < 0.01) were observed in portal hypertensive animals. In conclusion, the gastric vessels of the 15-day portal vein-ligated rat resemble the structural abnormalities described in human portal hypertensive gastropathy. © 1992.