Retrospective angiographic study to determine the effect of atherosclerotic stenoses of upstream arteries on the degree of atherosclerosis in distal vascular territories.

OBJECTIVE: Experimental coarctation of the aorta prevents the development of downstream atherosclerosis. The aim of this study was to find out whether or not atherosclerotic stenoses protect distal vascular territories from developing atherosclerosis in humans. DESIGN AND SETTING: A total of 2125 vascular segments from angiographies of 101 patients were evaluated by calculating the maximum degree of stenosis (NASCET criteria), the degree of calcification, the degree of collaterals and the Friesinger score. RESULTS: Stenosis ≥30-49% was found in 685 vascular segments (32.2%), ≥50-69% in 490 (23.1%), ≥70-89% in 373 (17.6%) and ≥90% in 265 (12.5%). If a stenosis of at least ≥70-89% was present in the common iliac, the external iliac or the common femoral artery, the degrees of stenosis distal to it were lower than those on the contralateral side (19.8±22.3% (CI 11.7 to 28.0) vs 25.2±20.7% (CI 21.2 to 29.1); Friesinger scores 1.1±1.2 (CI 0.6 to 1.5) vs 1.4±1.1 (CI 1.2 to 1.6); degrees of calcification 0.8±1.0 (CI 0.4 to 1.1) vs 1.2±1.1 (CI 1.2 to 1.6); p<0.05 each). This effect depended on the degree of proximal stenosis, but not on collaterals, and was most pronounced distal to stenoses of the common iliac, the superficial femoral and the popliteal artery. In regression models, stenoses of the pelvic arteries were shown to be an independent protective factor for the distal vascular territories. CONCLUSIONS: Atherosclerotic stenoses seem to protect distal vascular territories from developing atherosclerosis. The underlying pathophysiological mechanism of this phenomenon remains to be determined. It could be based on pulse pressure reduction.