An optical coherence tomography and endothelial shear stress study of a novel bioresorbable bypass graft

Figures

• 

  Figure 1. Routine imaging acquisitions (coronary angiogram and OCT) at 180 days and µCT at 200 days. (a) 2D angiographic views of biorestorative polymeric coronary bypass grafts and the two consecutive OCT pullback locations. (b) The two OCT pullbacks were manually matched and combined to form a single longitudinal view. The “flap” covers a length of 3.5 mm (35 frames), as indicated by the yellow dashed lines. (c) Selected 2D OCT cross-sections within the “flap” segment. The white dash line indicates the circumferential location of the longitudinal view in (b). (d) displays co-registered µCT images at 200 days. Red arrows point to the remaining shoulders of the “flap”, which was originally identified at 180 days OCT images. (e) 3D OCT representation of the “flap”. (f) 3D computer-aided design model of the bypass graft using the 3D-QCA-OCT reconstruction technique. A section view A–A (with distal segment removed at black dashed line) shows the internal view of the “flap” with (and without) the OCT catheter. µCT micro-computed tomography, OCT optical coherence tomography, QCA quantitative coronary angiography.

• 

  Figure 2. Section view A–A (Fig. 1f) with flow pattern distal to the “flap” with (left panels) and without the catheter (right panels). Results are shown at peak blood flow velocity (a,b) and minimum blood flow velocity (c,d). White arrows point to the flow recirculation distal to the flap.

• 

  Figure 3. ESS patterns on the XABG at selected angiogram frame time points: peak (time pt. 2), median [time pt. 6 (dashed line)] and minimum blood flow (time pt. 9). Insets show the section view A–A and the corresponding ESS pattern distal to the “flap”. White and yellow arrows point to the low ESS region on the graft lumen and “flap” surface, respectively. Red dotted circles highlight the focal region of low ESS at distal anastomosis. (a) CFD with the OCT catheter and (b) CFD without the OCT catheter. CFD computational fluid dynamic simulation, ESS endothelial shear stress, OCT optical coherence tomography, XABG Xeltis coronary artery bypass graft.

• 

  Figure 4. OSI patterns on the XABG: (a) with and (b) without the catheter. Insets show section views A–A and the corresponding OSI patterns distal to the “flap”. Red dotted circles highlight the focal region of high OSI at distal anastomosis. (c) Cartoon showing the impact of different OSI on the flap. OSI oscillatory shear index. XABG Xeltis coronary artery bypass graft.