Platelet reactivity in vivo in dogs with arterial prostheses seeded with endothelial cells.

This study was designed to assess platelet activity in vivo with vascular prostheses seeded with endothelial cells to determine the time course for development of thromboresistance and to test the ability of prostheses to produce prostacyclin. Sixteen dogs were randomly allocated to receive seeded (experimental group) or unseeded (control group) velour Dacron aortic prostheses. Serial measurements of platelet survival were performed to assess platelet interaction with prostheses in vivo, and platelet serotonin was monitored as an index of platelet release in vivo. After placement of prostheses, dogs in the experimental group had rapid normalization of platelet survival, with most having normal platelet survival at 4 to 8 weeks after surgery. In contrast, most control animals had reduced platelet survival throughout the 12 week period of study. Significant differences between groups in mean platelet survival were noted at 8 weeks after surgery (p less than .005) and in mean platelet serotonin at 12 weeks after surgery (p less than .05). Luminal surface production of 6-keto-PGF1 alpha from seeded prostheses was similar to aortic production and significantly greater (p less than .05) than that of control prostheses. Gross thrombus was present on 6.0 +/- 3.4% of the prosthetic surface in experimental animals in comparison to 26.6 +/- 19.2% in controls (p less than .005). The results of these studies document accelerated nonreactivity with platelets of seeded prostheses due to rapid coverage with endothelium possessing a normal ability to produce prostacyclin.