Cardiac Imaging to Screen Anatomical Suitability for Transapical Transcatheter Mitral Valve Implantation with a Tether-Based Device

Background: This analysis sought to assess effectiveness of simple but standardized multi-slice computed tomography (MSCT) and transthoracic echocardiographic (TTE) measurements for their ability to discriminate between patients who passed anatomical screening for Tendyne (Abbott Vascular, CA, USA) transcatheter mitral valve implantation (TMVI).

Method: Between 01/2016 and 09/2019, a total of 496 patients were screened for TMVI. MSCT- and TTE-screening measurements included left ventricle diameter at end-systole (LVESD) and end-diastole (LVEDD) and mitral intercommissural (IC) diameter. Measurements were performed by independent core laboratory blinded to results of MSCT analysis. Receiver operating characteristic (ROC) curves were constructed for anatomic variables of interest. Area under the curve (AUC) was used to characterize performance of each anatomic measurement in correctly classifying subjects as anatomically suitable. Relationship between MSCT and TTE-derived dimensions was assessed using Pearson's correlation and Bland-Altman analysis.

Results: Of 257 subjects meeting clinical eligibility criteria and with mitral anulus dimensions within the manufacturer's suggested range, 153 (59.5%) underwent TMVI, while 104 (40.5%) were excluded for other anatomic reasons, with risk of left ventricle outflow tract obstruction being the most common. MSCT-derived LVESD had the highest discriminatory power for predicting anatomical suitability, with an area under the curve of 0.908 (p < 0.0001). MSCT and TTE measured LVESD-dimension showed a linear correlation (r = 0.75), but statistical analysis demonstrated a systematic difference with MSCT measurements being ~5.4 ± 7.3 mm larger on average than TTE. LVESD as measured by TTE demonstrated smaller AUC than LVESD assessed by MSCT for predicting anatomical suitability (AUC = 0.840 for TTE vs. 0.908 for MSCT). IC-diameter was systematically underestimated in TTE compared with MSCT (mean difference –3.8 ± 5.1 mm) with a weak linear correlation (r = 0.555).

Conclusion: In addition to MSCT measured effective predictors LVESD and IC-diameter, LVESD measured by TTE can be used as an easy-to-obtain parameter for initial screening of anatomical suitability for this tether-based TMVI device.

Publication History

Article published online:
03 February 2022