Anatomic location of atherosclerosis in thoracic aorta: Clinical confirmation of atherogenic hypothesis by transesophageal echocardiography

Arterial points of flow separation are areas where blood flow may be disturbed and provide favorable conditions for atherogenesis. The pathophysiology of atherogenesis has been indicated by using the T-junction model. To test this hypothesis clinically, we studied the maximal thickness (THK) of the plaques including intimai and medial layers, and its ultrasonic imaging features in 98 pts (age 71±8 yrs, male 58) with transesophageal echocardiography (TEE) in ascending and descending aorta, proximal and distal arch. Imaging features of plaque were evaluated with echo-patterns of ulceration, calcification with shadowing, or different echogenicity without shadowing (fibrous, hemorrhagic), as well as its mobilization. Results: Plaque Mobile THK(mm) versus pt. n(%) n(%) I II III I Ascending aorta 52(53) 1(1) 4.3±2.0 II Descending aorta 85(87) 5(5) 6.4±2.2*III Proximal arch 89(91) 5(5) 7.1±2.8*# IV Distal arch 97(99) 25(25) 8.2±2.9**◇ (*p<0.0001; ◇p<0.002; #p=0.05) Plaques with mobile components were detected in 32(33%) pts, mostly (78%) locating in the distal arch. Complex plaques with ulceration, either with calcification or no shadowing were present in 92% pts in the distal arch, 89% in the proximal arch and descending aorta, but in only 8% pts in the ascending aorta. Thus, most thickened and complex plaques as well as mobile elements are present in the arch, especially at branch points and flow separation. As an important source of systemic emboli, advanced atherosclerosis of the aortic arch may be clinically determined by TEE.