Large Field-of-View Intravascular Ultrasound for Mitral and Tricuspid Valve-in-Valve Guidance: A Pilot Study

Area of Science:

• Cardiovascular Imaging
• Interventional Cardiology
• Biomedical Engineering

Background:

• Transcatheter heart valve (THV) expansion may deviate from nominal during valve-in-valve (VIV) procedures for degenerated surgical heart valves (SHV).
• Accurate assessment of THV expansion is crucial for optimal procedural outcomes.

Purpose of the Study:

• To compare THV expansion measurements using intravascular ultrasound (IVUS) versus multi-slice computed tomography (MSCT).
• To assess the correlation between THV dimensions and transvalvular gradients post-VIV implantation.

Main Methods:

• A pilot study involving 14 patients undergoing mitral/tricuspid VIV SAPIEN 3 implantation.
• Comparison of periprocedural IVUS (n=6) with postprocedural MSCT (n=9) for THV dimension assessment.
• Analysis of 190 MSCT and 124 IVUS cross-sections to evaluate THV expansion and transvalvular gradients.

Main Results:

• Excellent agreement was found between IVUS and MSCT measurements of THV dimensions (ICC ≥0.986).
• IVUS revealed smaller THV expansion in the inflow/middle regions (85.9%, 83.8%) compared to the outflow (98.8%) due to SHV ring overlap.
• Increased transvalvular gradients were observed from periprocedural to predischarge, with minimal inner THV frame diameter predicting maximal gradient.

Conclusions:

• Large field-of-view IVUS is feasible for periprocedural measurement of actual THV expansion in VIV procedures.
• Minimal inner THV stent frame dimensions are independently associated with increased postprocedural transvalvular gradients.