MSCT guided sizing of the Edwards Sapien XT TAVI device: impact of different degrees of oversizing on clinical outcome.

Aims: Prospective data on the usage of 3-dimensional imaging based annulus sizing on the outcome of TAVI is not available yet and there is general uncertainty about the optimal degree of oversizing. In the current study we therefore assessed a 3-D MSCT guided over-sizing approach and evaluated the clinical outcome of different degrees of oversizing.

Methods: TAVI-size-selection was done using systolic MSCT-annulus cross-sectional-area (CSA) measurements in 107 patients with severe aortic stenosis with the goal to oversize the 3rd generation balloon expandable Edwards Sapien XT (ESTV) device in relation to the native aortic annulus CSA.

Results: Among different degrees of oversizing there were no differences in the occurrence of stroke, myocardial infarction and death. No aortic injuries were observed. The overall rate of >mild postprocedural aortic regurgitation (PAR) was 7.6%. Increasing oversizing ratios are associated with lower rates of >mild PAR (r = -0.236, p<0.02) with the lowest rate of >mild PAR in patients with area based oversizing ratios >25% and the highest rate in patients with oversizing ratios <15% (0% vs. 15.8%, p<0.02). The rate of postprocedural permanent pacemakers tended to be lower in patients with <15% oversizing compared to those with >25% oversizing (5.3 vs. 16.7%, p<0.23).

Conclusions: MSCT guided ESTV-device sizing is safe and is associated with significantly lower than previously reported rates for PAR. A device/annulus oversizing ratio of 15-25% based on area and 7-12% based on mean diameter appears to provide the best risk-benefit ratio in terms of PAR reduction and conduction disorders.