Experimental coronary dilatation
Percutaneous coronary transluminal angioplasty has had increasing clinical application in patients with focal stenotic noncalcific coronary artery stenoses. The effects of coronary angioplasty have been evaluated in detail angiographically and a sequence of angiographic changes occurs with time in the immediate period after angioplasty and follow-up studies. Immediately following angioplasty the dilated area has a slightly “shaggy” endothelial appearance. In some cases there is not much improvement in lumen size seen angiographically. If the procedure is successful, lumen size is usually improved by at least 20% to 30% and in many cases to 70% or 80%. The irregular endothelial appearance seen angiographically in immediate postangioplasty angiograms is most prominent in femoral angioplasty sites, but is also seen after coronary angioplasty. In 6-month follow-up angiograms, “remodeling” of the dilated area is seen with smoothing of the inner surface of the artery. Frequently, there is improvement in lumen size compared to immediate postangioplasty angiograms. This angiographic appearance of remodeling implies that active changes have occurred within the vessel wall in the area of angioplasty. Remodeling of the medial/intimal surface may provide a larger, smoother lumen in the area that was previously stenotic.
Experimental angioplasty studies have been used to evaluate the pathophysiologic changes that occur immediately and following transluminal angioplasty. Attempts have been made to correlate pathologic changes seen in experimental models with the angiographic appearance seen in human angioplasty experience. Studies of experimental angioplasty have been performed at autopsy in human coronary arteries with coronary atherosclerosis, in normal canine coronary . . .