Transluminal angioplasty in experimental atherosclerosis. Analysis for embolization using an in vivo perfusion system.

We used polarized light microscopy and thin-layer chromatography to determine whether embolization of atherosclerotic material occurs after transluminal angioplasty. The experimental model consisted of an in vivo perfusion system of the atherosclerotic rabbit left iliac artery. Of eight rabbits that underwent successful angioplasty, four had angiographic evidence of dissection and three showed aneurysm formation. Histologic studies demonstrated fracture of the intimal plaque, dissection, and stretching of the noninvolved portion of the vessel. Perfusate analysis revealed no detectable cholesterol by thin-layer chromatography in six of eight rabbits. In two rabbits, a very small amount of cholesterol was measured, which was totally accounted for by hemorrhage into the perfusate rather than from cholesterol in the plaque. No evidence of arterial wall embolic debris could be detected by polarized light microscopy in seven rabbits, but lipid debris from the plaque was found in the perfusate of one rabbit that had excessive arterial trauma. We conclude that the major mechanism of successful transluminal angioplasty in this experimental model is intimal fracture combined with stretching of a noninvolved portion of the vessel. Furthermore, embolization of atheromatous lipid debris was an uncommon event related to arterial trauma during catheter placement rather than transluminal angioplasty itself.