Patient-specific coronary stenoses can be modeled using a combination of OCT and flow velocities to accurately predict hyperemic pressure gradients.

Computational fluid dynamics (CFD) is increasingly being developed for the diagnostics of arterial diseases. Imaging methods such as computed tomography (CT) and angiography are commonly used. However, these have limited spatial resolution and are subject to movement artifact. This study developed a new approach to generate CFD models by combining high-fidelity, patient-specific coronary anatomy models derived from optical coherence tomography (OCT) imaging with patient-specific pressure and velocity phasic data. Additionally, we used a new technique which does not require the catheter to be used to determine the centerline of the vessel. The CFD data were then compared with invasively measured pressure and velocity. Angiography imaging data of 21 vessels collected from 19 patients were fused with OCT visualizations of the same vessels using an algorithm that produces reconstructions inheriting the in-plane (10 µm) and longitudinal (0.2 mm) resolution of OCT. Proximal pressure and distal velocity waveforms ensemble averaged from invasively measured data were used as inlet and outlet boundary conditions, respectively, in CFD simulations. The resulting distal pressure waveform was compared against the measured waveform to test the model. The results followed the shape of the measured waveforms closely (cross-correlation coefficient = 0.898 ± 0.005, ), indicating realistic modeling of flow resistance, the mean of differences between measured and simulated results was -3. 5 mmHg, standard deviation of differences (SDD) = 8.2 mmHg over the cycle and -9.8 mmHg, SDD = 16.4 mmHg at peak flow. Models incorporating phasic velocity in patient-specific models of coronary anatomy derived from high-resolution OCT images show a good correlation with the measured pressure waveforms in all cases, indicating that the model results may be an accurate representation of the measured flow conditions.

Location of side branch access critically affects results in bifurcation stenting: Insights from bench modeling and computational flow simulation.

BACKGROUND: The aim of this study was to evaluate the impact of stent design and side branch access on final strut apposition during bifurcation stenting. METHODS AND RESULTS: A series of 6 different commercially available Drug Eluting Stents (DES) (n=42) were deployed in an identical model of a coronary bifurcation. Kissing Balloon (KB) optimization was performed after either proximal or distal recrossing of the guidewire and results were analyzed by micro-Computed-Tomography. Stent design only had a minor impact on side branch lumen area free of stent struts. Similar rate of strut malapposition was observed within the bifurcation when a consistent KB optimization protocol and an optimal distal recrossing of the wire to reaccess the side branch (SB) are followed. Conversely, proximal instead of distal cell recrossing toward the side branch produced a significant lower area of the side branch lumen free of struts than an optimal distal recrossing (60.3±7.1% versus 81.1±8.0%, p<0.0001), as well as a higher rate of strut malapposed toward the SB ostium (40.6±6.0% versus 26.0±5.7%, p=0.0005). CONCLUSIONS: Optimal cell recrossing of the guidewire may be critical to ensure successful stent optimization in bifurcation PCI.