Morphometric changes in normal arteries and those undergoing transluminal angioplasty.

To understand the morphometric effects of balloon catheter angioplasty in autopsy specimens, we studied the effect of histologic preparation on the size of control arterial specimens (N) and those having angioplasty at room temperature (CD) or body temperature (WD). Diameters of external and internal iliac arteries were measured with calipers, photography, and X-rays without any distention, after 200 mm Hg in a balloon catheter, after angioplasty to 4 atmospheres, and after fixation with a balloon catheter in place was inflated to 200 mm Hg. Arterial diameters were also taken from the tissue blocks and histologic slides. Images taken from the photos, X-rays, tissue blocks, and slides were digitized, and the diameter was calculated from circumference measurements. Diameters increased approximately 30% (P less than .001) when distended from the resting state to 200 mm Hg. There was a 7.4-8.2% decrease in diameter of arteries in blocks (P less than .01) and a further decrease of 9.8-11.9% from block to slide (P less than .005). Thus, significant size changes occur during arterial preparation. The postmortem artery shrinks without any distending pressure. Paraffin embedding and slide preparation are also associated with significant decreases in arterial size. These changes may influence the understanding of the pathophysiology of angioplasty and the estimation of stenoses by histopathology.