Variable extension of the transitional zone in the medial structure of carotid artery tripod

Background: The goal of our study was to demonstrate the extension of the t ransitional zone (TZ) between elastic and muscular medial structure in caro tid artery tripod Patients and methods: A histologic study of 56 probes from 8 carotid artery tripods rt as performed. The probes were obtained from autopsies of 4 adul ts (mean age: 47.5 years, range 38 to 55 years) and were taken from 7 diffe rent topographic sites. Results: At each level of the CCA (at 1 cm and 2 cm proximal to the bifurca tion as well as at the bifurcation) we observed an elastic arterial type in 24 (42.8%) probes with 11 to 20 (medium 15.0) elastic fibers per view fiel d (200 x magnification) in the media. In contrast the histologic structure of the ICA and ECA varied as follows: in 8 sections (14.3%) elastic arteria l type with 11 to 16 (medium 13.1) elastic fibers, in 11 sections (19.6%) m uscular arterial type with 2 to 5 (medium 3.5) elastic fibers and in 9 sect ions (16.1%) a transitional arterial type with 6 to 8 (medium 6.7) elastic fibers in the media. Atherosclerotic lesions hav prevented the assessment o f the arterial type in 4 probes (7.1%). The TZ in the menial structure of c arotid artery tripods is exclusively localized in the ICA/ECA but not in th e CCA. The ICA/ECA presented a TZ with a length I rp to 0.5 cm (4 probes; 25%), li p to 1.5 an (4 probes; 25%) and longer than 1.5 cm (6 probes; 37.5%). Conclusions: In this study we confirmed that in the carotid artery tripod a TZ - an arterial segment with transition from elastic to muscular type - d oes exist, involving a variable length. Furthermore studies on the impact o f the biomechanical properties of the TZ as a potential factor in atheroscl erotic disease are justified In addition, the complex biomechanical behavio r of the TZ should be considered prior to interventional procedures.