Cyclooxygenase Activity in the Thoracoabdominal Aorta After 24 Hours of Intraaortic Balloon Counterpulsation: An Assessment of the Effects of Localized Mechanical Trauma

Abstract

Using a canine model, the authors evaluated the effects of twenty-four hours of intraaortic balloon counterpulsation (IABCP) on the morphology of the thoracoabdominal aorta and its spontaneous and arachidonate stimulated pro duction of prostacyclin (PGI₂). The treated group was counter-pulsed at a 1:1 ratio with a 40 cc balloon. The control group had the balloon inserted and left deflated across the thoracoabdominal aorta.

There were no differences between the IABCP or sham groups in prostanoid production either in the thoracic or abdominal aorta. Baseline PGI₂ production in the control versus treated group of thoracic aortas was 1880 ± 1140 pg/cm²/ min vs 1992 ± 1125. The stimulated response in the control group, 9180 ± 1198, was statistically different from baseline (P < .001). The stimulated in crease in the IABCP group, 6269 ± 5240, relative to baseline was also signifi cant (P < .01). There were no significant differences, either between or within groups in the abdominal aortas. Poststimulation values (30 min) were signifi cantly below baseline in each group in each section of the aorta (P < .05). Light microscopy showed a statistically significant difference in endothelial preserva tion between the control and the balloon group, 66 ± 25% vs 19 ± 17% (P < 0.05) .

The authors conclude that IABCP results in severe endothelial destruction but that spontaneous and stimulated PGI₂ production is unimpaired. It remains to be determined whether the aorta may sustain long-term damage due to the repair process after IABCP.