Short-term tracking of atherosclerosis in operated and unoperated human carotid arteries by high resolution magnetic resonance imaging.
Academic Article
Overview
abstract
INTRODUCTION: A previous study demonstrated the efficacy of a phospholipid (PL) complexed with a protein (apoAI Milano) in causing 4.6% regression of atheroma volume as assessed by intravascular ultrasonography (IVUS) in a group of 47 patients with carotid atherosclerosis. The results of this study raised the question of whether the phospholipid alone could produce a similar effect. METHODS: To answer this question a trial of 39 subjects at five sites was designed. Patients with > 15% stenosis of at least one carotid artery as determined by US underwent intravenous PL (200 mg/kg) or placebo infusions weekly for 8 weeks. The wall/outer wall ratio, percent lipid-rich/necrotic core, and percent calcification were measured as a proportion of the vessel wall by magnetic resonance imaging (MRI) at 0, 4, 8, and 14 weeks. RESULTS: The substudy of seven of these patients evaluated at our site allowed comparison of the dimensions of five unoperated-unoperated carotid pairs and two operated-unoperated pairs. In patient 1, MRI measurements on unoperated left and unoperated right carotids tracked almost identically over the 14-week study. Both carotids showed similar increases in the volumes of the total wall (+61% vs. 56%), the normal wall (+51% vs. 49%), and plaque (+99% vs. 85%). Both carotids showed similar decreases in lumen volume (-11% vs. -17%). The other four unoperated-unoperated carotid pairs showed dimensional changes over 14 weeks similar to those of patient 1. In patient 2, who underwent left endarterectomy, the operated carotid had a total artery volume of 2300 mm(3), about twofold greater than the unoperated carotid (1100 mm(3)). Operated and unoperated carotid measurements tracked in parallel. The unoperated carotid had volume increases of 25% (+200 mm(3)) in total wall, +19% (+100 mm(3)) in normal wall, and 43% (+75 mm(3)) in plaque. The operated carotid lumen showed no significant changes. Patient 7, who also underwent left endarterectomy, exhibited carotid changes similar to those of patient 2. CONCLUSIONS: Individual unoperated carotid pairs have volumes that track almost identically. In unilateral operated carotid pairs, the operated artery has 1.5- to 2.0-fold greater volume than unoperated carotids. In each of our two unilaterally operated patients, the operated carotid had decreased plaque volume (-3%, -58%), whereas the unoperated carotid had increased plaque volume (+43%, +7%). Among the five unoperated patients, one pair had 85%/99% increase in plaque volume; one pair had -15%/-10% decrease; and the other three pairs had intermediate changes. This study provides additional support to the view that unoperated human carotid arteries are bilaterally symmetrical.
