Atherosclerotic Arterial Remodeling in the Superficial Femoral Artery Individual Variation in Local Compensatory Enlargement Response

Background: In previous studies on atherosclerotic arterial remodeling, compensatory enlargement of the artery in response to plaque accumulation was inferred from pooled data based on one cross section per artery. We assessed local arterial remodeling individually by analyzing 45 artery segments at 0.5-cm intervals over a length of 10 to 15 cm. Methods and Results: Twenty patients were studied by 30-MHz intravascular ultrasound (IVUS) before balloon angioplasty of the superficial femoral artery (370 cross sections), and 25 femoral artery segments were studied postmortem (551 cross sections). In each cross section, the area surrounded by the internal elastic lamina (IEL area) and the plaque area were measured. The IEL area was larger in the cross section with the largest plaque area than in the cross section with the smallest plaque area (32.5±13.0 and 32.0±11.5 mm² versus 28.9±9.7 [P=NS] and 26.7±10.1 [P<.05] mm² for IVUS and histology, respectively [mean±SD]). A significant positive correlation was found between plaque area and IEL area for the pooled data (r=.61 and r=.47 and slope=1.07 and 0.90 for IVUS and histology, respectively; both P<.001). In 12 of 20 and 16 of 25 individual arterial segments, however, no significant correlation was observed between plaque area and IEL area for IVUS and histology, respectively. A large variation was found in the correlation of the regression of plaque to IEL area (IVUS, r=-.40 to .89; histology, r=-.13 to .91) and slope (IVUS, -0.28 to 1.29; histology, -0.18 to 1.32). Conclusions: In the majority of atherosclerotic femoral arteries, significant compensatory enlargement could not be determined. It is inferred that arterial remodeling in response to plaque formation may vary among individuals.