O/sub 2/ metabolism in blood vessel walls with stenoses

Abstract

Vascular tissue O/sub 2/ partial pressure (PO/sub 2/) measurements with recessed cathode O/sub 2/ microelectrodes were made in the walls of isolated rabbit abdominal aortas during saline perfusion in vitro. Three months prior to the experiments, the aortic lumen was reduced by approximately 50% using a tantalum metal clip. A 2- to 3-cm segment of the abdominal aorta including the stenosis was removed and mounted in a chamber maintained at 19.9 kPa. With constant perfusion, the minimum tissue PO/sub 2/ in the wall varied axially along the segment. The minimum wall PO/sub 2/ (+or-SE) was 13.5+or-0.4 kPa at the location 5 mm upstream and 14.2+or-0.8 kPa at the location 5 mm downstream. The lowest value, 11.6+or-0.8 kPa, was found 1 mm downstream. O/sub 2/ disappearance rates (dPO/sub 2//dt) at each location were also measured after stopping perfusion to the segment. The disappearance rates varied axially, with the fastest rate, -4.1+or-0.6 kPa/min, found 1 mm upstream. At 4 and 5 mm upstream and downstream from the stenosis, the rates were essentially the same, at 2.8+or-0.3 kPa/min. The average value for O/sub 2/ metabolism at the upstream and downstream ends is 5.0*10/sup -4/ mL O/sub 2//mL tissue/min.<>