A Doppler-exclusive non-invasive computational diagnostic framework for personalized transcatheter aortic valve replacement

Abstract

Given the associated risks with transcatheter aortic valve replacement (TAVR), it is crucial to determine how the implant will affect the valve dynamics and cardiac function, and if TAVR will improve or worsen the outcome of the patient. Effective treatment strategies, indeed, rely heavily on the complete understanding of the valve dynamics. We developed an innovative Doppler-exclusive non-invasive computational framework that can function as a diagnostic tool to assess valve dynamics in patients with aortic stenosis in both pre- and post-TAVR status. Clinical Doppler pressure was reduced by TAVR (52.2 ± 20.4 vs. 17.3 ± 13.8 [mmHg], p < 0.001), but it was not always accompanied by improvements in valve dynamics and left ventricle (LV) hemodynamics metrics. TAVR had no effect on LV workload in 4 patients, and LV workload post-TAVR significantly rose in 4 other patients. Despite the group level improvements in maximum LV pressure (166.4 ± 32.2 vs 131.4 ± 16.9 [mmHg], p < 0.05), only 5 of the 12 patients (41%) had a decrease in LV pressure. Moreover, TAVR did not always improve valve dynamics. TAVR did not necessarily result in a decrease (in 9 out of 12 patients investigated in this study) in major principal stress on the aortic valve leaflets which is one of the main contributors in valve degeneration and, consequently, failure of heart valves. Diastolic stresses increased significantly post-TAVR (34%, 109% and 81%, p < 0.001) for each left, right and non-coronary leaflets respectively. Moreover, we quantified the stiffness and material properties of aortic valve leaflets which correspond with the reduced calcified region average stiffness among leaflets (66%, 74% and 62%; p < 0.001; N = 12). Valve dynamics post-intervention should be quantified and monitored to ensure the improvement of patient conditions and prevent any further complications. Improper evaluation of biomechanical valve features pre-intervention as well as post-intervention may result in harmful effects post-TAVR in patients including paravalvular leaks, valve degeneration, failure of TAVR and heart failure.

Incremental prognostic value of intensity-weighted regional calcification scoring using contrast CT imaging in TAVR

“… 4 , 13 Similarly, determination of the calcium burden and distribution pattern in the AV and left ventricular outflow tract (LVOT) are predictors for PVL, annular rupture, and the need for a second valve implantation. 7 , 11 , 17 The relationship between post-TAVR complications and TAVR risk assessment both with or without pre- or post-dilatation is ambiguous. 10 For example, the presence of severe valvular calcium is a mechanical barrier to the ideal device expansion, and it might seem appropriate to perform a pre-dilation to improve subsequent implantation.…”

“…This is indicative that calcification patterns primarily play a role in adjudicating clinical decision in device selection, sizing, expansion rate, positioning, and dilation strategy, especially in balloon-expandable devices. Further analysis using computer-aided simulations 17 , 18 , 20 , 21 , 25 or in vitro experiments 22 could help shed light on the interaction between these factors.…”