Long-term results of 1 millimeter arterial anastomosis using the 3M precise microvascular anastomotic system.

The 3M Precise Microvascular Anastomotic System has been tested experimentally in long-term studies of arteries of 1 mm in diameter for the first time. The device was placed, using a newly described technique, in the infrarenal aorta of 25 rats. At different intervals (2 weeks, 16 weeks, and 1 year), the section containing the 3M Precise Microvascular Anastomotic System was removed and processed for light microscopy and scanning electron microscopy. All the anastomoses were found to be patent. Using a new device to process the material, both light microscopy and scanning electron microscopy at 2 weeks showed a perfect reparative process at the junction site and the presence of a continuous endothelial layer. Media atrophy was responsible for wall thinning within the device. At 16 weeks, the atrophy of the media was even more marked, reducing the vessel wall thickness within the device to one-third of normal. At 1 year, this atrophy of the media was complete; smooth muscle cells disappeared and were replaced by fibrous tissue. Adventitia was not present over the long term within the device. The continuous endothelial layer, however, was still viable. These long-term results suggest that scar tissue forms within the device, while a continuous endothelial layer remains viable internal to this.