Preoperative planning for TEVAR is based on the Aortic Arch Map with zones 0–4,
described by Ishimaru, that defines the proximal landing zone (PLZ) for the endograft,
and the associated debranching procedure. However,
the Aortic Arch Map does not account for PLZ angulation,
which represents a critical anatomic feature for adequate endograft fixation.
Our aim was to assess whether the additional use of Aortic Arch Classification in Type II,
originally developed for predicting difficult...
Methods and Materials
We retrospectively evaluated 60 patients (mean age 71±8 years,
70% male) which underwent to preoperative CT angiography.
All cases were stratified according to Aortic Arch Classification,
and 20 patients of each Type of Arch (ToA) were selected.
We used two methods to calculate the β angle: 1) wall to wall method; 2) center line method (Fig.1).
β angles were independently measured by one blinded investigator using both method,
and classified into cases of mild (<40°),
Angulation was moderate in I/0,
and in II/0,
Angulation was also moderate in III/0,
and in III/1,
and it was severe in III/2,
and in III/3.
Linear regression analysis showed significant increase in angulation depending on ToA using the two different methods (p<0.001).
Within ToA II and III,
angulation decreased significantly when moving towards more proximal landing zones (p<0.001 and p=0.001,
respectively) using the wall to wall method.
Aortic Arch Classification is associated with a consistent geometric pattern of the Aortic Arch Map,
that identifies specific PLZs with suboptimal angulation for stent-graft deployment.
Although both methods can be used to measure β angle,
the wall to wall method is more accurate in the evaluation of decrease of angulation in ToA II and III that are considered less favorable anatomy for TEVAR.