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Predicted vs Observed Valve to Coronary Distance in Valve-in-Valve TAVR: A Computed Tomography Study
Georgios Tzimas1, Mariama Akodad2, David Meier2
1Center for Heart Valve Innovation, St. Paul's Hospital, University of British Columbia, Vancouver, British Columbia, Canada; Service of Cardiology, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland.
Insights
Preprocedural computed tomography (CT) measurements for valve-in-valve transcatheter aortic valve replacement (ViV TAVR) may underestimate post-TAVR distances due to underexpansion. Postdilatation can alter these distances, impacting accuracy.
Area of Science:
- Cardiology
- Radiology
- Medical Imaging
Background:
- Preprocedural computed tomography (CT) is used to predict coronary obstruction risk during valve-in-valve transcatheter aortic valve replacement (ViV TAVR).
- Virtual transcatheter heart valve-to-coronary ostia (VTC) and valve-to-sinus (VTS) distances are assessed pre-TAVR to estimate risks.
Purpose of the Study:
- To evaluate the agreement between predicted VTC/VTS distances and actual post-TAVR CT measurements.
- To assess the relationship between these distances and transcatheter heart valve (THV) expansion and deployment.
Main Methods:
- Fifty-one patients undergoing balloon-expandable ViV TAVR were studied.
- THV stent frame expansion was evaluated at four levels: inflow, sewing ring, outflow, and THV outflow.
- Pre-TAVR CT (VTC/VTS) and post-TAVR CT measurements were compared.
Main Results:
- THV stent frames were generally underexpanded post-ViV TAVR, especially at the sewing ring.
- Postdilatation significantly increased THV expansion compared to nominal balloon filling.
- Observed distances differed from predicted distances: larger with nominal filling, smaller with postdilatation.
Conclusions:
- Pre-TAVR VTC/VTS distances can underestimate post-TAVR distances due to THV underexpansion with nominal balloon filling.
- Postdilatation may lead to overexpansion and distances smaller than predicted, particularly at the outflow level.
Background:
Preprocedural computed tomography (CT) workup with assessment of virtual transcatheter heart valve-to-coronary ostia (VTC) distance and transcatheter heart valve-to-sinus (VTS) distances is recommended to assess the risk of coronary obstruction following valve-in-valve (ViV) transcatheter aortic valve replacement (TAVR).
Objectives:
The authors sought to investigate the agreement of predicted VTC and VTS distances and observed post-TAVR anatomy on CT and their relationship with transcatheter heart valve (THV) expansion and deployment conditions.
Methods:
Fifty-one patients who underwent a balloon-expandable ViV procedure were included in this study. The expansion of the THV stent frame was evaluated at 4 levels: THV inflow, surgical heart valve (SHV) sewing ring, SHV outflow, and THV outflow. Assessment of the VTC/VTS distances was performed on the pre-TAVR CT, and THV-to-coronary ostia and THV-to-sinus distances were assessed on the post-TAVR CT.
Results:
Following the ViV procedure, the THV stent frame flared toward the outflow but was generally underexpanded at all levels, particularly at the SHV sewing ring level. Postdilatation impacted the extent of THV expansion, resulting in greater expansion than nominal balloon filling at all 4 THV levels (P < 0.001). Observed THV-to-coronary ostia distances were systematically larger than predicted by the VTC distance (mean difference 1.25 ±1.28 mm) in patients with nominal balloon filling but systematically smaller in case of postdilatation (mean difference -0.45 ± 0.52 mm). A similar relationship was observed between VTS and THV-to-sinus distance measurements.
Conclusions:
With nominal balloon filling, VTC and VTS distances underestimate postprocedural distances due to THV frame underexpansion. However, postdilatation may lead to distances smaller than predicted due to THV overexpansion at the outflow level.
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