We investigated the histological changes between arteries constricted by endothelin for 7 days and vasospastic arteries induced by the double injection of autologous blood. Group 1 was a sham-operated group. Group 2 animals received a continuous cisternal injection of endothelin-1 (1.7 x 10(-9) mol/7 days) by a miniosmotic pump implanted in the neck musculature for 7 days. Group 3 received double injections of cisternal blood administered 48 hours apart. Angiography showed severe constriction of the basilar artery, 34.6% and 43% in Groups 2 and 3, respectively, on Day 7. Histological study showed marked constriction of the basilar artery in both Group 2 and Group 3. Degenerative changes in endothelial cells and smooth muscle cells were observed in both Group 2 and Group 3. Immunohistochemical study demonstrated endothelin-1 in the endothelial cells in Group 2, but not in Group 1 or in Group 3. It is suggested that endothelin-1 may play an important role in the pathogenesis of cerebral vasospasm.

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Percutaneous transluminal angioplasty for treatment of cerebral vasospasm was performed in primates. Chronic cerebral vasospasm was induced by placement of an autologous blood clot over the right internal carotid artery (ICA), middle cerebral artery (MCA), and anterior cerebral artery (ACA). Cerebral angiography on Day 7 showed that the diameters of the ICA, MCA, and ACA were reduced to 55.7% +/- 1.3%, 55.3% +/- 2.6%, and 59.6% +/- 1.3%, respectively, of baseline. The angioplasty was carried out with a silicone microballoon attached to a microcatheter under somatosensory evoked potential (SEP) monitoring on Day 7. The angioplasty for ICA was performed satisfactorily; however, the balloon could not be advanced to the spastic M1 or A1 portions of the cerebral artery. Following angioplasty, the diameters of the ICA, the M1 segment, and the A1 segment were 79.6% +/- 2.9% (p < 0.001), 67.6% +/- 4.3% (p < 0.05), and 61.7% +/- 2.2% (not significant), respectively, of baseline. Histological studies demonstrated that the vessels were well dilated and patent without endothelial cell damage.

An artificial blood vessel with an endothelial-cell monolayer was used as an arterial substitute in rats. Endothelial cells were isolated from the aorta of a Wistar rat by the digestion method. The cell identification was established by the cobblestone appearance of a confluent cell monolayer, by an expression of factor VIII-related antigen, and by the presence of Weibel-Palade bodies. The luminal surface of the thin-walled polytetrafluoroethylene (PTFE) graft (4 mm in diameter and 10 mm in length) was coated with an endothelial-cell monolayer for 7 days in vitro. An interpositional graft was placed using the endothelial cell-coated PTFE prosthesis on the right common carotid artery in seven rats. A total of 10 rats received an interpositional graft with the noncoated PTFE prosthesis as a control. The patency rate at 1 month after implantation was significantly higher in the coated group than in the control group. The vascular prosthesis with an endothelial-cell monolayer is a promising technique to inhibit the development of thrombosis.

This dynamic method can advance the time of detection of early ischemia in comparison with T2-weighted MR imaging and provides functional information about hemodynamics not provided by other methods of MR imaging.