Effects of Systemic and Local Caffeine on Vessel Diameter, Anastomosis Patency, and Intimal Hyperplasia in the Rat.

Abstract

The use of caffeine is not recommended prior to elective microsurgery due to its demonstrated negative effects on vessel anastomosis by the presumed sympathomimetic induction of vasoconstriction. In this study, we aimed to elucidate the systemic and local effects of caffeine on vessel diameter, anastomosis patency, and degree of intimal hyperplasia during the healing process. Twenty-five rats were randomly assigned to five groups: (1) negative control, (2) preoperative systemic caffeine, (3) postoperative systemic caffeine, (4) perioperative systemic caffeine, and (5) a local caffeine group. Both the right and left femoral arteries were used. Ten anastomoses were performed per group. The arterial diameter was measured by micrometer, anastomosis patency was assessed surgically and histologically, and the histological examination was conducted 3 weeks postoperatively to determine intimal hyperplasia. The overall patency rate was 96%. Mild vasoconstriction was observed in the systemic caffeine groups (statistically insignificant); however, there were no negative effects on anastomosis patency. Local caffeine irrigation resulted in significant vasodilatation in the local caffeine group (p = 0.001); a similar effect was not observed in the other groups. There was a significant decrease in the intima/media ratio in the local caffeine group (p < 0.01), when compared with the control and systemic caffeine groups. No other intima/media ratio differences were observed among other comparison groups. The systemic administration of caffeine, although statistically insignificant, has an observable effect on vasoconstriction. However, it does not appear to have negative effects on anastomosis patency regardless of its application period (pre-, post-, or perioperatively). The local application of caffeine resulted in considerable vasodilatation as opposed to the vasoconstriction effect in the systemic caffeine groups. Decreased intimal hyperplasia at the anastomosis edge, and antifibrotic properties in the surgical field were also observed in this group. Histologically, the local caffeine group demonstrated an additional beneficial effect on anastomosis remodeling.