Patient-Specific Computer Simulation to Predict Conduction Disturbance With Current-Generation Self-Expanding Transcatheter Heart Valves

Figures

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  Figure 1. Patient-specific computer simulation. (a) Baseline ECG demonstrated no significant conduction disturbance. (b) Cardiac CT imaging demonstrated a trileaflet valve with moderate valvular calcification. (c and d) A finite element model of the aortic root was created. (e) Procedural contrast angiography was reviewed and (f) finite element analysis performed to simulate the same implantation depth. (g) The membranous septum was identified in 3 locations, and a region of interest defined corresponding to the atrioventricular bundle and proximal left bundle branch. The percentage of this area (contacted pressure index [CPI]) and maximum pressure exerted by the THV (CPMax) was recorded. In this example, computer simulation predicts major conduction disturbance (CPI 51%, CPMax 0.50 MPa). (h) Postprocedural ECGs demonstrated left bundle branch block. ∗Values above this maximum are displayed in the high color in the scale. Abbreviations: CT, computed tomography; ECG, electrocardiogram; THV, transcatheter heart valve.

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  Figure 2. Indications for permanent pacemaker implantation. The most common indication for PPM was third-degree atrioventricular block. Abbreviations: AF, atrial fibrillation; AVB, atrioventricular block; LBBB, left bundle branch block; PPM, permanent pacemaker; RBBB, right bundle branch block.

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  Figure 3. Discriminatory power to predict the development of major conduction abnormalities. Contact pressure index (CPI), maximum contact pressure (CPMax), and THV implantation depth were predictive of major conduction abnormalities, whereas membranous septum (MS) length did not demonstrate any discriminatory power. Diagonal segments are produced by times. Abbreviation: THV, transcatheter heart valve.

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  Figure 4. Patient-specific THV positioning. (a) A patient underwent TAVI with a 26-mm Evolut PRO THV, developing LBBB. (b) Conduction disturbance simulation predicts major conduction disturbance (CPI 25%, CPMax 0.82 MPa). (c and d) Computer simulation suggests that implanting the THV in a high position will reduce the risk of conduction disturbance (CPI 6%, CPMax 0.11 MPa). (e) A patient underwent TAVI with a 34-mm Evolut R THV, requiring implantation of a PPM for third-degree atrioventricular block. (f) Conduction disturbance modeling predicts major conduction disturbance (CPI 48%, CPMax 0.46 MPa). (g and h) Computer simulation of a high implant suggests that the patient may remain at risk major conduction disturbance (CPI 6%, CPMax 0.51 MPa). Abbreviations: CPI, contact pressure index; CPMax, maximum contact pressure; LBBB, left bundle branch block; PPM, permanent pacemaker; THV, transcatheter heart valve.

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  Figure 5. Patient clinical outcomes. (a) Postprocedural length of stay was longer in patients who required implantation of a PPM and in patients where computer simulation predicted a higher contact pressure from the THV. (b) LVEF increased in patients who did not develop major conduction disturbance, in patients who did not have a PPM implantation, and in patients where computer simulation predicted a low maximum contact pressure. (c) At 3 years, an elevated CPMax was associated with a higher risk of death from any cause. Green boxplots/bars represent the absence of factors, and red boxplots represent the presence of factors. Error bars represent 95% CI. Abbreviations: CI, confidence interval; CPMax, maximum contact pressure; LVEF, left ventricular ejection fraction; PPM, permanent pacemaker; THV, transcatheter heart valve.

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  Figure 6. Potential utility for patient-specific transcatheter heart valve deployment. (a) A finite element model of the aortic root has been created, and a 3-cusp view identified. (b) Finite element analysis is performed to simulate the implanted THV. (c) Conduction disturbance modeling indicates a low risk of conduction disturbance (CPI 4%, CPMax 0.38 MPa). (d) During the procedure, the computer simulations could be used to match this target implant depth. (e-h) This process can be repeated in the cusp-overlay view. Abbreviations: CPI, contact pressure index; CPMax, maximum contact pressure; THV, transcatheter heart valve.

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  Figure 7. Patient-specific computer simulation in a patient at high risk for conduction disturbance. (a) A patient with pre-existing RBBB (b) had a finite element model of their aortic root created. (c) Finite element analysis and (d) conduction disturbance modeling is performed, demonstrating a low risk of conduction disturbance (CPI 1%, CPMax 0.05 MPa). (e) Deployment of a THV at this implantation depth (f) did not result in any new conduction disturbance. Abbreviations: CPI, contact pressure index; CPMax, maximum contact pressure; RBBB, right bundle branch block; THV, transcatheter heart valve.