[Evaluation of Changes in Membranous Septum Length during the Cardiac Cycle and by Measurement Methods Using the Preoperative CT for Transcatheter Aortic Valve Replacement: A Single-center Cross-sectional Study].

PURPOSE: The purpose of this study was to evaluate the changes in membranous septum (MS) length during the cardiac cycle and by measurement methods using the preoperative computed tomography (CT) images for transcatheter aortic valve replacement (TAVR).

METHOD: Among 34 consecutive patients who underwent preoperative contrast-enhanced CT for TAVR, we measured MS lengths by three measurement methods (coronal, stretched, and reformatted coronal view method) at 10% intervals in the cardiac cycle.

RESULT: MS lengths differed between the three measurement methods in all cardiac phases. Moderate correlations were observed between the MS lengths measured by the coronal view method and the other two methods. In contrast, strong correlations were observed between the MS lengths measured by the stretched view method and the reformatted coronal view method. The frequencies of the minimum and maximum MS lengths during the cardiac cycle tended to be highest at R-R 90% and R-R 30%, respectively. The median MS lengths at R-R 90% were smaller than those at R-R 30% in all measurement methods.

CONCLUSION

The MS length in patients undergoing contrast-enhanced CT for TAVR varies notably depending on the cardiac cycle and measurement methods. When evaluating MS length, it is crucial to consider the measurement method and to perform measurements during diastole in order to evaluate the minimum value during the cardiac cycle.