Ethan J. Halpern MD, Presenter: Nothing to Disclose

Praneil Patel MD, Abstract Co-Author: Nothing to Disclose

Hugh White MD, Abstract Co-Author: Nothing to Disclose

When performing transcatheter aortic valve replacement (TAVR), the cranial margin of the fabric surrounding the prosthesis must be positioned below the orifices of the coronary arteries. Axial images obtained from CT angiography (CTA) demonstrate an asymmetric appearance to the aortic root, and suggest a more superior origin of the left coronary artery (LCA) as compared with the right coronary artery (RCA). The purpose of this study was to define the position of the coronary artery origins relative to the aortic annulus and root at CTA.

This retrospective study reviewed 52 consecutive ECG-gated cCTA examinations of the thoracic aorta and coronary arteries. Two independent reviewers evaluated the position of the coronary artery origins visualized on CTA using the Brilliance 3D workstation (Philips Medical Systems). Measurements were obtained along the long axis of the aortic root to define the distance from the aortic annulus to each coronary artery origin.

Analysis of variance for the length of the aortic root demonstrated no significant effect based upon side (right vs left), cardiac phase (diastole vs systole), or reader (p>0.55). Mean length of the aortic root (± standard deviation) was 2.2cm ± 0.05. The coronary arteries originated below the sinotubular junction in all subjects. Analysis of variance for the height of the coronary artery origins demonstrated a significant effect based upon side (F=14.4; p=0.0002), but no effect based upon cardiac phase (F=0.3; p=0.6). The RCA origin was slightly closer to the sinotubular junction than the LCA origin (mean of 1.6cm vs 1.5cm above the aortic annulus) in both diastole and systole.

The aortic root is a clover-shaped symmetric structure, measuring approximately 2.2cm in length, with both coronary arteries arising just below the sinotubular junction. Although the LCA origin is superior to the RCA origin in the chest, the RCA origin is actually slightly further from the aortic annulus and closer to the sinotubular junction.

When a stent/prosthesis is implanted within the aortic root, the covered portion of the stent must terminate below the coronary artery origins. The distance between the aortic annulus and the origins of the coronary arteries is not accurately assessed on axial images, but can be measured in long axis on a 3D workstation. The mean height of the coronary artery origins is 1.5cm above the aortic annulus.

Halpern, E, Patel, P, White, H, Normal Position of the Origins of the Coronary Arteries within the Aortic Root.  Radiological Society of North America 2014 Scientific Assembly and Annual Meeting, - ,Chicago IL. http://archive.rsna.org/2014/14045430.html