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Biomedical subjects

V B Graves

Publications and source records attributed to V B Graves.

At least 37 records · Page 2Linked to original sources
PubMedDate not supplied

A new guidewire with kink-resistant core and low-friction coating.

A new guidewire constructed from kink-resistant titanium-nickel alloy, polyurethane, and hydrophilic polymer is described. We have used this wire in 119 angiographic and 49 interventional procedures without complications. In numerous applications, it offers significant advantages over other guidewires. It is particularly helpful for angiography and interventional procedures requiring catheterization through markedly tortuous vessels, tight stenoses, or occlusions.

Alloys↗
PubMedDate not supplied

MR imaging of spinal pachymeningitis.

We report a case with pathologic correlation that demonstrates the magnetic resonance imaging characteristics of spinal pachymeningitis. Contrast enhanced T1-weighted images clearly demonstrated the thickened contrast enhancing meninges in a patient with progressive radiculomyelopathy who had both clinical and imaging evidence of progression of disease.

Aged↗
PubMedDate not supplied

Flow dynamics of lateral carotid artery aneurysms and their effects on coils and balloons: an experimental study in dogs.

PURPOSE: To investigate the hemodynamic characteristics of lateral carotid artery aneurysms in a canine model and to determine their influence on coils and balloons. MATERIALS AND METHODS: Forty aneurysms were created in fourteen dogs and their hemodynamic characteristics and influence on coils and balloons were evaluated with angiography and color Doppler pre- and postplacement. Twenty aneurysms were treated with coils, eight with balloons, and 12 aneurysms served as controls. RESULTS: The aneurysms demonstrated three distinct zones of flow: 1) an inflow zone entering at the distal aspect of the aneurysm ostium, 2) an outflow zone exiting at the proximal ostium, and 3) a central slow flow vortex. The inflow zone is a determining factor in the placement and stability of coils and balloons placed within the aneurysm and in the thrombosis of an aneurysm. The force of the inflow is considerable and can alter the shape of coils and displace both coils and balloons positioned within the aneurysm. CONCLUSIONS: Coils and balloons need to be of shapes and sizes that do not conform to the inflow and outflow zones. Filling the aneurysm and blocking or displacing the inflow zone can produce thrombosis of an aneurysm with preservation of the parent artery.

Angioplasty, Balloon↗
PubMedDate not supplied

Aneurysm hemodynamics: an experimental study.

PURPOSE: To study the flow of blood in aneurysms. METHODS: A canine model was used to study the hemodynamics of lateral, bifurcation, and terminal aneurysms with angiography and color Doppler techniques. FINDINGS: Flow within experimental aneurysms, although not laminar, is seldom if ever turbulent, but rather is highly predictable, varying primarily according to the relationship of the aneurysm to its parent artery. CONCLUSIONS: These studies support earlier in vitro work and provide further evidence that not all aneurysms share similar stresses. A more complete understanding of these hemodynamic features will be useful in the establishment of criteria that allow recognition of those aneurysms that are more or less likely to rupture, to grow, or to thrombose.

Aneurysm↗
PubMedDate not supplied

Treatment of carotid artery aneurysms with platinum coils: an experimental study in dogs.

The objectives of this study were to investigate the consistency, patency, and natural history of a vein graft canine aneurysm model and to determine the effectiveness of various coil designs on inducing aneurysm thrombosis. Twenty-one sacculuslike aneurysms were created in mongrel dogs by anastomosing a vein pouch to the common carotid artery. The model produced wide-neck aneurysms with 100% patency. The canine vein graft aneurysm provided an excellent model for the evaluation of endovascular devices. Three types of specially designed platinum coils were placed in the aneurysms: those with simple curves, those with complex curves, and those with flower petal curves and silk fibers. These coils were placed by the endovascular route by means of microcatheters. Flower petal coils with silk fibers were effective in producing thrombosis of the aneurysms, suggesting that coils of the appropriate design may be useful in the endovascular treatment of aneurysms. The other coil designs evaluated, those with simple and complex curves without silk fibers, demonstrated insufficient thrombogenicity and spatial stability.

Animals↗
PubMedDate not supplied

Biocompatibility of 1-French polyethylene catheters used in interventional neuroradiology procedures: a study with rats and dogs.

This study was designed to investigate the thrombogenicity, inflammatory response, and endothelial response to the presence of sterilized, 1-French polyethylene catheters implanted into the arterial system and subcutaneous tissues of 18 rats and two dogs. At time periods ranging from 1 week to 6 months, repeat angiography was done, the animals sacrificed, and the tissues containing the catheter removed for histologic study. In the subcutaneous tissues the catheter became encased in a very thin (less than 0.5 mm) coating of fibrous tissue with no evidence of inflammation. In large vessels, the catheter at all time periods appeared identical both angiographically and histologically to that at the time of implantation. In small to medium-sized vessels a slight increase in vessel size (25% increase in diameter of the rat iliac) was observed angiographically. On histologic evaluation, there was evidence of myointimal hypertrophy, which was asymmetrically placed, centered around the position of the catheter. There was no evidence of thrombi or of incorporation of the catheter itself into the hypertrophic tissue. In dogs and rats, an implanted 1-French polyethylene catheter is well tolerated: the animals showed no evidence of thrombotic, thromboembolic, or inflammatory complications. Myointimal hypertrophy was observed in small to medium-sized arteries, which is of unknown significance.

Animals↗
PubMedDate not supplied

Treatment of experimental canine carotid aneurysms with platinum coils.

PURPOSE: To evaluate and compare the deliverability, positioning, stability, and effectiveness of aneurysm occlusion and the incidence of parent-artery thrombosis of two different types of platinum coils, using a canine carotid aneurysm model. METHODS: 29 experimental canine carotid aneurysms (19 lateral, 6 bifurcation, and 4 terminal) were constructed and treated with complex-shaped fibered platinum coils and simple curved nonfibered platinum Guglielmi detachable coils (GDCs). RESULTS: Fibered complex coils were stable, producing 38% complete aneurysm occlusion and 61% average reduction in aneurysm lumen size but resulting in 19% parent artery occlusions. GDC coils were stable, producing 31% complete aneurysm occlusion and 95% average reduction in aneurysm lumen size with no parent-artery occlusions. CONCLUSIONS: GDC coils produced an average reduction in aneurysm lumen size of 95% without any associated parent-artery occlusions. There were no delayed migrations of GDC coils. The ability to remove, reposition, and detach a coil was the most significant feature of the GDC coil.

Aneurysm↗
PubMedDate not supplied

Canine model of terminal arterial aneurysm.

A canine model of terminal aneurysms using a venous pouch surgical technique is described. This model mimics the anatomy and hemodynamics of some types of carotid and basilar tip aneurysms. This technique produces aneurysms 15 x 21 mm in size. The aneurysms have been used to investigate the hemodynamics and treatment of terminal aneurysms.

Aneurysm↗