Right ventricular outflow tract histology post-stenting and in-stent stenosis

Figures

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  Figure 1. (a) Intraoperative findings after opening the main pulmonary artery longitudinally demonstrating the RVOT stent. (b) Explanted stent in toto with surrounding cardiac tissue. (c) CT scan with 3D reconstruction demonstrating the RVOT stent with adequately grown branch PAs. RVOT - Right ventricular outflow tract, CT - computerized tomogram, 3D - Three-dimensional

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  Figure 2. (a) Explanted stent in toto with surrounding cardiac tissue (b) Histopathology of the tissue surrounding the explanted stent (detailed description of histopathology is in Figure 3) (H and E staining, ×100). Zone-1: No adherent tissue. Zone-2: No inflammation seen in the native pulmonary valve. Zone-3: Divided into upper/distal (zone 3a) and lower/proximal (zone 3b). Higher grades of inflammation and neovascularization seen as we move proximally from zone 3a to zone 3b

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  Figure 3. Zonal histopathology (H and E staining, × 400). (a) Zone-2 (native pulmonary valve) demonstrating maintained valvar architecture with endothelial lining (arrow), no evidence of inflammation or foreign body reaction. (b) Zone-3a, tissue protruding into the lumen through the stent interstices demonstrates neointimal formation with neovascularization (arrow) and atrophic myocardial fibers (*). (c) Zone-3b, dense lymphoplasmacytic infiltrate adjacent to the stent with foreign body giant cells (arrow) seen with neovascularization and atrophic myocardium