Catheter-induced intimal injury during routine coronary catheterization in dogs

The location and progression of changes in arterial permeability and structure were studied in nine dogs over a 13-week period following left coronary catheterization with standard coronary catheters. Changes in arterial permeability were analyzed by quantitating Evans blue dye (EBD) uptake over the aortic luminal surface (blue areas). Structural changes were assessed by light and electron microscopy. In the catheterized animals, compared to uncatheterized controls, we observed a significant increase in aortic luminal EBD uptake that was maximal 4 hours after the procedure but still present up to 13 weeks later. Microscopic analysis of "blue areas" shortly after the procedure revealed widespread endothelial denudation, platelet and leukocyte adherence, with occasional intimal avulsions, disruption of the internal elastica, and thrombi. The EBD uptake patterns in association with the electron microscopic findings in these animals suggested that 67-89% of the aortic endothelium was removed by the catheter during the procedure. The proliferative response that occurred following this catheter-induced injury produced fibrocellular intimal thickening in the aortas and left main coronary arteries of animals studied 10 to 92 days after the procedure. In the aortic root, such thickening was associated with incomplete re-endothelialization, thrombogenicity, and grossly abnormal permeability patterns. We conclude that significant catheter-induced intimal injury can occur during coronary angiography. In the canine model, such injury is associated with widespread fibrocellular intimal thickening and abnormal permeability that persists for at least 13 weeks after the procedure.