Distribution of Calcium in the Ascending Aorta in Patients Undergoing Transcatheter Aortic Valve Implantation and Its Relevance to the Transaortic Approach

Objectives 
This study sought to identify how many patients suitable for transcatheter aortic valve implantation (TAVI) would have a contraindication for the transaortic (TAo) approach due to ascending aortic calcification.

Background 
TAo is an emerging approach for implantation of the Sapien valve through the ascending aorta. A "porcelain aorta" is often considered a contraindication for the TAo approach. This may not always be true, as the TAo procedure requires a small calcium-free area for the purse-string suture, usually in the upper outer quadrant of the distal ascending aorta, identified as the "TAo zone."

Methods 
A total of 237 patients underwent TAVI between February 2008 and June 2011. Multislice computed tomography scans (MSCT) were analyzed for distribution of calcium with special attention to the TAo zone. Each MSCT was interrogated in cross section and three dimensional (3D) reconstructions. Correlation between the calcium distribution on MSCT and the 3D reconstruction with the clinical findings was sought in patients undergoing the TAo procedure.

Results 
The vast majority of patients had calcification in the aortic arch (n = 154, 64.9%) and aortic root (n = 220, 92.8%). Of the 237 patients, only 1 patient had diffuse calcification in the ascending aorta, including the TAo zone, thus precluding a TAo procedure. MSCT and 3D reconstruction data in the 33 patients who underwent a TAo procedure, including 6 who were identified as having porcelain aorta preoperatively, correlated very well with the absence of calcium in the TAo zone during surgery. There were no post-procedure neurological events in this group.

Conclusions 
Conventionally defined porcelain aorta should not be considered a contraindication for performing TAVI by the TAo approach.