Jonathan Avrom Leipsic MD, Presenter: Speakers Bureau, General Electric Company Speakers Bureau, Edwards Lifesciences Corporation Medical Advisory Board, General Electric Company Medical Advisory Board, Edwards Lifesciences Corporation

Cameron John Hague MD, Abstract Co-Author: Nothing to Disclose

Alexander Willson, Abstract Co-Author: Nothing to Disclose

David Wood MD, FRCPC, Abstract Co-Author: Consultant, Edwards Lifesciences Corporation Consultant, St. Jude Medical, Inc

Ronald Binder, Abstract Co-Author: Nothing to Disclose

John Webb MD, FRCPC, Abstract Co-Author: Consultant, Edwards Lifesciences Corporation

  CT annular measurements have strong predictive value of paravalvular regurgitation post TAVR which is a predictor of mortality and morbidity. At present, no formal structure for CT based sizing has been proposed. The purpose of our study was to develop and demonstrate safety of computed tomography (CT) sizing guidelines for transcatheter aortic valve replacement (TAVR).

    The proposed CT sizing guidelines ensure all transcatheter heart valves are over sized relative to the aortic annulus (THV external area > CT annular area). A percentage of annular over sizing is measured by (THV area/CT annular area -1) x 100. 120 consecutive patients underwent CT prior to TAVR with balloon expandable valves using standard echocardiography and clinical sizing recommendations. The theoretical CT THV size was compared to the actual size implanted.

   CT sizing would recommend upsizing of valve size in 33.3% (40/120), no change in valve size in 55.8% (67/120) and a smaller valve size in 10.8%(13/120). In patients where a larger valve was recommended by CT the incidence of at least moderate paravalvular regurgitation was 25% (10/40) compared to 4.5% (3/67) p<0.01, when no change in valve size was recommended. Traditional sizing methods resulted in 33.3%(40/120) of valves being under sized (THV area<CT annular area) but also 28% (34/120) of aortic annuli being oversized by at least 20% with a mean annular over sizing of 9.4±17.4% (range: -21.5% to 65.9%) and no cases of annular rupture. CT sizing would result in a mean annular over sizing of 13.9±8.0% (range 1.3 to 29.8%).  

  CT sizing using annular area enables routine controlled over sizing of the annulus in a safe manner that is likely to result in significantly lower rates of paravalvular regurgitation.

A CT based TAVR sizing protocol is needed to allow for more appropriate valve sizing to reduce the burden of paravalvular leak which has been shown to result in significantly worse clinical outcomes.

Leipsic, J, Hague, C, Willson, A, Wood, D, Binder, R, Webb, J, A Modern Computed Tomography Sizing Guideline for Balloon Expandable Transcatheter Aortic Valve Replacement  .  Radiological Society of North America 2012 Scientific Assembly and Annual Meeting, November 25 - November 30, 2012 ,Chicago IL. http://archive.rsna.org/2012/12031648.html