Original title: Automated 3-Dimensional Aortic Annular Assessment by Multidetector Computed Tomography in Transcatheter Aortic Valve Implantation. Reference: Yusuke Watanabe et al. J Am Coll Cardiol Intv 2013;6:955–64.
Percutaneous aortic valve implantation ( TAVI ) has emerged as an alternative for patients with severe aortic stenosis and high surgical risk. While this technique was improved over the time, residual paravalvular regurgitation is still a common occurrence and has been associated with worse outcomes. One of the primary causes of paravalvular failure is the underestimation of ring size when choosing a valve so that a correct measurement is essential. Multislice tomography allows 3D ring reconstruction in a reproducible manner, which could help to choose the right valve and potentially improve outcomes. The new image multislice tomography processing software (version 5.1. sp1 , Pie Medical Imaging BV , Maastricht , the Netherlands ) was designed to provide pre-operative measures of the aortic annulus in a precise, reproducible, automated and fast manner.
Between 2010 and 2012, 459 consecutive patients were treated with TAVI at a center of which 105 were chosen randomly to perform the pre-implant screening comparing the new software and the traditional manual measurements in the same patients. There was an excellent correlation measurement of he annulus between the automated software and manual measurement. The correlation coefficient for inter and intra observer reproducibility was also very good. The degree of ≥ mild aortic regurgitation was observed in 14 patients (31.8 %) , the ratio between the diameter of the valve and the average diameter of the ring by tomography and the relationship between the nominal area of the valve and ring area using CT, were the best predictors of aortic insufficiency post implant.
Conclusion:
The software to automatically process 3-D images by multislice tomography of the aortic valve ring provides reliable and reproducible measurements in patients who are planning a percutaneous aortic valve replacement while providing greater predictive value of the risk of aortic failure post implant than the manual measurement method.
Editorial Comment:
The aortic annulus is a complex three-dimensional structure with oval shape hindering measurement. 3D trans-esophageal echocardiography can measure transverse and perpendicular, but requires experienced operators and reproducibility is relatively low. It is true that the underestimation of the ring when choosing the size of the valve is a cause of aortic insufficiency, but not the sole one. So are the valve sub expansion for calcium nodules and the implant that can be too high or too low.
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