VIVA Stent Preclinical Evaluation in Swine: A Novel Cerebral Venous Stent with a Unique Delivery System

Abstract

Background: Venous sinus stenting is a promising treatment for intracranial venous disorders, such as idiopathic intracranial hypertension and pulsatile tinnitus, associated with transverse sinus stenosis. The VIVA Stent System (VSS) is a novel self-expanding braided venous stent designed to navigate tortuous cerebral venous anatomy. This preclinical study assessed the safety, thrombogenicity, and performance of the VSS in a swine model. Methods: Fifteen swine underwent bilateral internal mammary vein stenting with either the VSS (n = 9) or the PRECISE^® PRO RX stent (n = 6, reference). Fluoroscopy and thrombogenicity assessments were conducted on the day of stenting, clinical pathology analysis was carried out throughout the in-life phase, and CT Venography was performed before sacrifice. Animals were sacrificed at 30 ± 3 or 180 ± 11 days post-stenting for necropsy and histological evaluation. Results: Fluoroscopic angiography confirmed the successful VSS deployment with complete venous wall apposition and no vessel damage. The VSS achieved the highest scores on a four-point Likert scale for most performance parameters. No thrombus formation was observed on either delivery system. CT Venography confirmed vessel patency, no stent migration, and complete stent integrity. Histopathology showed a mild, expected foreign body reaction at 30 days, which resolved by 180 days, indicating normal healing progression. Both stents showed increased luminal diameter and decreased wall thickness at 180 days, suggesting vessel recovery. No adverse reactions were observed in non-target organs. Conclusions: The VSS exhibited favorable safety, procedural performance, and thromboresistance in a swine model, supporting its potential clinical use for treating transverse sinus stenosis and related conditions.

Keywords: VIVA Stent System; preclinical study; thrombogenicity; transverse sinus stenosis; venous sinus stenting; venous stenting.

Figure 1

(A,B). Representative histological images of the proximal segment (~0.5 cm from the stent’s edge) of the VIVA Stent (test device) in Animal 14256, retrieved from the left internal mammary vein at 1 month post-implantation. (A) Low-magnification view demonstrating the overall stent structure and tissue response. (B) High-magnification view highlighting key histopathological features. Thin arrows indicate stent struts, while thick arrows mark the neointimal layer forming around the stent. The arrowhead denotes a foreign body reaction surrounding the struts. Red/purple luminal protrusions reflect post-mortem clot formation, which is a normal histological artifact. (C,D) Representative histological images of the proximal segment (~0.5 cm from the stent’s edge) of the PRECISE^® PRO RX Stent (reference device) in Animal 14255, retrieved from the left internal mammary vein at 1 month post-implantation. (C) Low-magnification view illustrating the overall stent structure and surrounding tissue response. (D) High-magnification view providing detailed visualization of the neointimal reaction. Thin arrows indicate stent struts, while thick arrows highlight the neointimal layer. The arrowhead denotes a foreign body reaction surrounding the struts. Red luminal protrusions correspond to post-mortem clot formation, a common histological artifact. (E,F) Representative histological images of the proximal segment (~0.5 cm from the stent’s edge) of the VIVA Stent (test device) in Animal 14114, retrieved from the right internal mammary vein at 6 months post-implantation. (E) Low-magnification view showing the overall stent structure and tissue integration. (F) High-magnification view detailing the neointimal response and luminal characteristics. Thin arrows indicate stent struts, while thick arrows highlight the neointimal layer. Red luminal protrusions represent post-mortem clot formation, a normal histological artifact. (G,H) Representative histological images of the proximal segment (~0.5 cm from the stent’s edge) of the PRECISE^® PRO RX Stent (reference device) in Animal 14121, retrieved from the left internal mammary vein at 6 months post-implantation. (G) Low-magnification view displaying the overall stent structure and surrounding tissue response. (H) High-magnification view providing detailed visualization of the neointimal reaction. Thin arrows indicate stent struts, while thick arrows highlight the neointimal layer. Red luminal protrusions correspond to post-mortem clot formation, a normal histological artifact.