Vessel Occlusion

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Boston Scientific is committed to assisting Interventional Radiologists in improving patient care by developing products that facilitate successful vessel occlusion.

Vessel occlusion, also referred to as embolotherapy, is an image-guided percutaneous intervention designed to reduce or obstruct blood supply to targeted lesions or organs.

A catheter-based technique, occlusion is defined as the injection of occlusive material through a catheter into a blood vessel (or vessels) to produce a blockade of blood flow. The goal of the procedure is to produce a specific and effective vessel blockade that will be either temporary or permanent, depending upon the clinical indication for the intervention.

Applications for Vessel Occlusion

Among the applications for vessel occlusion, control of hemorrhage is perhaps the most common, providing a life-saving option for many patients. Vascular delivery of embolic material may control epistaxis, hemoptysis, upper and lower gastrointestinal bleeding, postpartum hemorrhage and trauma-associated bleeding.

A variety of vascular lesions can be treated with occlusion. Abnormal vascular communications such as arteriovenous malformations (AVMs) and arteriovenous fistulae (AVFs) may be corrected via precise placement of embolic materials to interrupt the blood flow. Potentially lethal consequences of aneurysm or psuedoaneurysm rupture may be avoided by embolization of the sac.

Preoperative organ ablation may be achieved with vessel occlusion, and it may also be used for control of endoleaks after stent graft placement for treatment of an abdominal aortic aneurysm.

Angiographic Assessment and Vessel Occlusion

As with many interventional procedures, vessel occlusion begins with detailed angiographic assessment. After percutaneous access to the vasculature is achieved and a guidewire is in place, an angiographic catheter is advanced over-the-wire and contrast is injected to visualize the vessel. It is critical that vessels to be occluded be clearly visualized.

Once the target vessel or vessels are accurately identified, the vessel occlusion phase of the procedure can proceed.

At times, the selective angiographic catheter that has already been utilized for angiographic assessment can be used for embolization. An angiographic catheter cannot, however, provide superselective vascular access and in this case, a coaxial approach must be used. In this technique, a microcatheter/microguidewire system is advanced through the angiographic catheter over-the-wire and the vessel is selected. The Fathom™ Steerable Guidewire is designed for access through tortuous vasculature, and the Renegade® STC Microcatheter is designed for distal access and exceptional flow.

Embolic Agents

Upon the completion of the angiographic assessment, an embolic agent is delivered via the microcatheter to provide effective occlusion. Boston Scientific’s Contour SE™ Microspheres, are compressible and designed to conform to the vessel wall, providing complete blockade.

An embolic agent should also provide targeted occlusion, meaning blockade at a precise location within the vessel, and therefore should be available in a range of sizes to allow selection of a size that will block the vessel at the desired site, without impacting proximally or flowing distally from that site. Boston Scientific’s retractable Interlock™ Fibered IDC Occlusion System is designed for control and precision in placement and is available in a variety of coil lengths, diameters and shapes. Contour® PVA Particles and Contour SE Microspheres are also available in a wide range of sizes, providing an excellent choice in embolic size and materials for different applications.

Radiographic visualization of embolic materials is also necessary. Some current embolic agents such as platinum coils, including the Interlock Fibered IDC Occlusion System, VortX® 35 Vascular Occlusion Coils and Fibered Platinum Coils, are radiopaque because of the material from which they are manufactured. Others, such as PVA microspheres including Contour SE Microspheres, are radiolucent and are routinely mixed with contrast to allow intraprocedure visualization of solution delivery.