Preprocedural computed tomography angiography-based conduction system simulation for optimized patient-specific transcatheter aortic valve implantation deployment.

BACKGROUND

Conduction disturbances requiring permanent pacemaker implantation (PPI) remain a major limitation to transcatheter aortic valve implantation (TAVI).

OBJECTIVE

We applied post hoc classification using a novel preprocedural computed tomography angiography (CTA)-based conduction system simulation technology to understand optimized patient-specific TAVI implantation depth to reduce PPI risk.

METHODS

CARA Metis conduction system simulation based on identifying key landmarks of the conduction axis was retrospectively applied to patients who received TAVI. Device depth was measured from postprocedural CTA. The primary outcome was postprocedural PPI. Post hoc classification of patients into 4 implantation strategies was applied: (1) patient-specific conduction system protocol vs (2) implantation 1-2 mm, (3) 2-3 mm, and (4) 3-4 mm below the aortic annulus, respectively.

RESULTS

Among 228 patients (median age 82.0; 57% female), 51 (22.4%) required PPI. Mean (standard deviation) distances of the estimated course of His bundle (point B and midpoint BC) and left bundle branch origin (point C) to the aortic annulus were 5.3 mm (2.3), 3.9 mm (2.1), and 2.5 mm (2.2), respectively. Implantation below the conduction pathway (n = 203) resulted in significantly higher odds of PPI (for each 1 mm below points B, midpoint BC, and C, odds ratio [OR] 1.25 [95% confidence interval {CI} 1.14-1.39], OR 1.27 [95% CI 1.14-1.42], and OR 1.24 [95% CI 1.12-1.38], respectively). Implantation above (n = 25) resulted in significantly fewer PPI (0.0% vs 17.4%, 10.0%, and 25.0% implanting above the patient's conduction system vs 1-2 mm, 2-3 mm, and 3-4 mm below the aortic annulus, respectively; P < .0001).

CONCLUSION

CTA-based conduction system simulation may offer a patient-specific, conduction-axis-guided TAVI deployment strategy, minimizing the need for PPI. The results of this study are hypothesis generating and require prospective trial validation.