Endovascular image-guided treatment of in-vivo model aneurysms with asymmetric vascular stents (AVS): evaluation with time-density curve angiographic analysis and histology

In this study, we compare the results obtained from Time-Density Curve (TDC) analysis of angiographic imaging sequences with histological evaluation for a rabbit aneurysm model treated with standard stents and new asymmetric vascular stents (AVS) placed by image-guided endovascular deployment. AVSs are stents having a low-porosity patch region designed to cover the aneurysm neck and occlude blood flow inside. To evaluate the AVSs, rabbits with elastase-induced aneurysm models (n=20) were divided into three groups: the first (n=10) was treated with an AVS, the second (n=5) with a non-patch standard coronary stent, and third was untreated as a control (n=5). We used TDC analysis to measure how much contrast media entered the aneurysm before and after treatment. TDCs track contrast-media-density changes as a function of time over the region of interest in x-ray DSA cine-sequences. After 28 days, the animals were sacrificed and the explanted specimens were histologically evaluated. The first group showed an average reduction of contrast flow into the aneurysm of 95% after treatment with an AVS with fully developed thrombus at 28 days follow-up. The rabbits treated with standard stents showed an increase in TDC residency time after treatment and partial-thrombogenesis. The untreated control aneurysms displayed no reduction in flow and were still patent at follow-up. The quantitative TDC analysis findings were confirmed by histological evaluation suggesting that the new AVS has great potential as a definitive treatment for cerebro-vascular aneurysms and that angiographic TDC analysis can provide in-vivo verification.

[1]  Stephen Rudin,et al.  Asymmetric Vascular Stent: Feasibility Study of a New Low-Porosity Patch-Containing Stent , 2008, Stroke.

[2]  Stephen Rudin,et al.  Evaluation of an asymmetric stent patch design for a patient specific intracranial aneurysm using computational fluid dynamic (CFD) calculations in the computed tomography (CT) derived lumen , 2006, SPIE Medical Imaging.

[3]  David F. Kallmes,et al.  Creation of Saccular Aneurysms in the Rabbit , 2000 .

[4]  Daniel R. Bednarek,et al.  Measurement of flow modification in phantom aneurysm model: comparison of coils and a longitudinally and axially asymmetric stent--initial findings. , 2004, Radiology.

[5]  Isabel Wanke,et al.  Double-stent method: therapeutic alternative for small wide-necked aneurysms. Technical note. , 2004, Journal of neurosurgery.

[6]  S. Tateshima,et al.  Matrix and Bioabsorbable Polymeric Coils Accelerate Healing of Intracranial Aneurysms: Long-Term Experimental Study , 2003, Stroke.

[7]  D. Ku,et al.  Fluid mechanics of vascular systems, diseases, and thrombosis. , 1999, Annual review of biomedical engineering.

[8]  Stephen Rudin,et al.  Flow modification in canine intracranial aneurysm model by an asymmetric stent: studies using digital subtraction angiography (DSA) and image-based computational fluid dynamics (CFD) analyses , 2006, SPIE Medical Imaging.

[9]  Christopher M. Putman,et al.  Qualitative comparison of intra-aneurysmal flow structures determined from conventional and virtual angiograms , 2007, SPIE Medical Imaging.

[10]  Ciprian N Ionita,et al.  Particle image velocimetry (PIV) evaluation of flow modification in aneurysm phantoms using asymmetric stents , 2004, SPIE Medical Imaging.

[11]  Daniel R. Bednarek,et al.  Angiographic analysis of blood flow modification in cerebral aneurysm models with a new asymmetric stent , 2004, SPIE Medical Imaging.

[12]  B. Sellhaus,et al.  Long-term Histological and Scanning Electron Microscopy Results of Endovascular and Operative Treatments of Experimentally Induced Aneurysms in the Rabbit , 2006, Neurosurgery.

[13]  Thomas Schmitz-Rode,et al.  Treatment of Experimentally Induced Aneurysms with Stents , 2005, Neurosurgery.

[14]  R. Close,et al.  X-ray videodensitometric methods for blood flow and velocity measurement: a critical review of literature. , 2000, Medical physics.