Hemodynamic Relevance Evaluation of Coronary Artery Anomaly During Stress Using FFR/IVUS in an Artificial Twin

Figures

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  Visual Summary. Comparison of Clinical and Artificial Twin Hemodynamics and Morphologic Changes: Fractional Flow Reserve and Intravascular Ultrasound of Anomalous Aortic Origin of Coronary Artery Under Rest and Stress Conditions The left column displays, from top to bottom, the patient’s CCTA, the patient’s 3-dimensional reconstruction, the coronary computed tomography angiography scan of the 3DPSP, and an image of the 3DPSP. The center column shows, from top to bottom, the patient’s resting measurements, including FFR and IVUS for both the ostial and intramural regions, followed by the 3DPSP’s resting measurements for FFR and IVUS in the same regions. The right column presents, from top to bottom, the patient’s stress measurements for FFR and IVUS (ostial and intramural, i.e. morphologic changes), and the 3DPSP’s corresponding stress measurements. 3DPSP = 3-dimensional printed patient-specific phantom; CCTA = coronary computed tomography angiography; FFR = fractional flow reserve; IVUS = intravascular ultrasound.

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  Figure 1. Schematic Overview of the Normal Coronary Artery Anatomy and Anomalous Aortic Origin of Coronary Artery and Depiction of the Anatomic Geometric Changes in Rest and Stress Conditions (Top) R-AAOCA with an interarterial course between the aorta and the pulmonary artery and intramural course (within the tunica media of the aortic wall). The green markers on the top panel indicate the ostium of the anomalous vessel with the slit-like vessel shape, whereas the orange markers indicate the locations of the intramural vessel lumen. The elliptic ratio is represented by the major axis (red) divided by the minor axis (blue). During stress, both the ostial and intramural stenosis are accentuated (decrease in lumen area), whereas the elliptic ratio increases. (Bottom) Normal anatomy is shown as a reference. Here, the ostium and the normal proximal vessel course are round with equal lengths of the major and minor axes. During stress, the lumen area may slightly increase, whereas the elliptic ratio remains unchanged. LCA = left coronary artery; R-AAOCA = right anomalous aortic origin of coronary artery; RCA = right coronary artery.

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  Figure 2. Workflow of 3DPSP Creation Workflow from CCTA-based creation of the 3DPSP to its integration into hemodynamic testing in the flow loop. 3DPSP = 3-dimensional–printed patient-specific phantom; CAD = computer-aided design; CCTA = coronary computed tomography angiography.

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  Figure 3. Detailed 3-Dimensional–Printed Patient-Specific Phantom Computer-Aided Design In the left panel, the isometric view of the 3-dimensional–printed patient-specific phantom (3DPSP) with marked components is shown. The connectors were used to provide access to the phantom with the clinical instrumentation through the access channel and to connect the right coronary artery to the coronary circuit. The connectors were fixed to the frame via flexible hinges to prevent the vessels from kinking. The hinges were made of flexible material to allow for limited movement of the right coronary artery, channel, and aorta during the cardiac cycle and reduce stresses at the contact points. In the right panel, the transversal section through the 3DPSP at the center of the right coronary artery ostium on the right is shown, with marked locations for the clinical pressure measurements in green and the locations for the cross-sectional evaluation of the intravascular ultrasound recording in red. The light green surface marks the cutting surface of the section. Blue represents VeroPureWhite (Stratasys) parts (frame and connectors). Gray represents Agilus30Clear (Stratasys) parts (seals, anatomy and…

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  Figure 4. Flow Loop Setup Flow loop setup with the ability to assess FFR and IVUS anatomic deformation of the anomalous coronary artery in resting and stress conditions (mimicked physical exercise with increasing heart rate and blood pressure). FFR = fractional flow reserve; IVUS = intravascular ultrasound.