Validating a prediction modeling tool for left ventricular outflow tract (LVOT) obstruction after transcatheter mitral valve replacement (TMVR).

OBJECTIVE: Demonstrate proof-of-concept validation of a computed tomography (CT) computer-aided design prediction modeling tool to identify patients at risk for left ventricular outflow tract (LVOT) obstruction in transcatheter mitral valve replacement (TMVR). BACKGROUND: LVOT obstruction is a significant and even fatal consequence of TMVR. METHODS: From August 2013 to August 2017, 38 patients in 5 centers underwent TMVR with compassionate use of balloon-expandable valves for severe mitral valve dysfunction because of degenerative surgical mitral ring, bioprosthesis, or severe native mitral stenosis from to severe mitral annular calcification. All patients had preprocedural CT scans performed for anatomic screening, intraprocedural TEE and invasive hemodynamics performed. Preprocedural prediction modeling was performed utilizing computer-aided design (CAD) of the neo-LVOT post-TMVR. Post-TMVR CT scans were obtained and compared to pre-TMVR LVOT modeling datasets for validation. RESULTS: All patients underwent successful TMVR without device embolization. Seven of the 38 patients experienced LVOT obstruction, defined as an increase of ≥10 mmHg LVOT peak gradient post-TMVR. Anatomic screening using CT was validated in 20/38 patients as preprocedural predicted neo-LVOT surface area correlated well with post-TMVR measurements (R2 = 0.8169, P < 0.0001). A receiver operating curve curve found a predicted neo-LVOT surface area of ≤ 189.4 mm2 to have 100% sensitivity and 96.8% specificity for predicting TMVR-induced LVOT obstruction. CONCLUSION: CAD design and CT postprocessing are indispensable tools in predicting LVOT obstruction and necessary for anatomic screening in percutaneous TMVR.

Application of 3-Dimensional Computed Tomographic Image Guidance to WATCHMAN Implantation and Impact on Early Operator Learning Curve: Single-Center Experience.

OBJECTIVES: The aim of this study was to examine the impact of 3-dimensional (3D) computed tomographic (CT) guided procedural planning for left atrial appendage (LAA) occlusion on the early operator WATCHMAN learning curve. BACKGROUND: Traditional WATCHMAN implantation is dependent on 2-dimensional transesophageal echocardiographic (TEE) sizing and intraprocedural guidance. METHODS: LAA occlusion with the WATCHMAN device was performed in 53 patients. Pre-procedural case plans were generated from CT studies with recommended device size, catheter selection, and C-arm angle for deployment. RESULTS: All 53 patients underwent successful LAA occlusion with the WATCHMAN. Three-dimensional CT LAA maximal-width sizing was 2.7 ± 2.2 mm and 2.3 ± 3.0 mm larger than 2-dimensional and 3D TEE measurements, respectively (p ≤ 0.0001). By CT imaging, device selection was 100% accurate. There were 4 peri-WATCHMAN leaks (<4.5 mm) secondary to accessory LAA pedunculations. By 2-dimensional TEE maximal-width measurements alone, 62.3% (33 of 53) would have required larger devices. Using 3D TEE maximal-width measurements, 52.8% of cases (28 of 53) would have required larger devices. Three-dimensional TEE length would have inappropriately excluded 10 patients from WATCHMAN implantation. Compared with the average of 1.8 devices used per implantation attempt in PROTECT AF (WATCHMAN Left Atrial Appendage System for Embolic Protection in Patients With Atrial Fibrillation) (82% success rate), the present site averaged 1.245 devices per implantation attempt (100% success rate). There were no intraprocedural screen failures and no major adverse cardiac events. CONCLUSIONS: Three-dimensional CT image case planning provides a comprehensive and customized patient-specific LAA assessment that appears to be accurate and may possibly facilitate reducing the early WATCHMAN implantation learning curve.