MORPHOLOGICAL-CHANGES IN HUMAN CEREBRAL-ARTERIES AFTER PERCUTANEOUS TRANSLUMINAL ANGIOPLASTY FOR VASOSPASM CAUSED BY SUBARACHNOID HEMORRHAGE

LIGHT AND ELECTRON microscopy were used to study morphological changes in cerebral arteries after percutaneous transluminal angioplasty (PTA ) for vasospasm in two patients with aneurysmal subarachnoid hemorrhag e. One patient died of gastric bleeding 5 days after PTA. Postmortem e xamination of the inflated middle cerebral arteries revealed heterogen eously extended walls and dilated lumina. Throughout the vessel walls, the extracellular matrix, which was composed of nonmuscle components such as increased collagen, was stretched in conjunction with the medi al muscle component. Also, torn and thinned areas of the wall and intr amural hemorrhages were caused by overinflation. The second patient di ed of massive cerebral infarction caused by diffuse vasospasm 5 days a fter PTA. Prominent stretching of the walls at the atheromatous plaque margin in the dilated vessel was found in addition to the morphologic al changes observed in the first patient. These observations suggest t hat characteristic pathological alterations might be present in the ve ssel wall at the site of angioplasty. The major mechanism of the long- lasting effects of PTA seems to be the stretching and disruption of bo th the degenerative muscle and the proliferative nonmuscle components, mainly in the media of the vasospastic vessels.