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Case 7-Aneurysms and Guglielmi Coils

Case 7 - Treatment of Cerebral Aneurysms with Intravascular Delivered Coils: Guglielmi Detachable Coil (GDC)

Motivation

Repair of a cerebral aneurysm is in some sense the inverse of stenting a coronary artery stenosis in that it is a treatment of widened blood vessels that are at risk of rupture. The problem is often described as analogous to filling in a pot hole in a highway.

Background

Source: http://www.webmd.com/brain/tc/brain-aneurysm-topic-overview

What is a brain aneurysm? A brain (cerebral) aneurysm is a bulging, weak area in the wall of an artery that supplies blood to the brain. In most cases, a brain aneurysm causes no symptoms and goes unnoticed. In rare cases, the brain aneurysm ruptures, releasing blood into the skull and causing a stroke.

When a brain aneurysm ruptures, the result is called a subarachnoid hemorrhage. Depending on the severity of the hemorrhage, brain damage or death may result.

The most common location for brain aneurysms is in the network of blood vessels at the base of the brain called the circle of Willis. In the image immediately below an arteriogram that shows an unruptured aneurysm at the vertebrobasiliar junction.

Source of http://emedicine.medscape.com/article/252142-overview - showall

The image below illustrates conceptually what can happen when the aneurysm ruptures. The volume of lost of blood is not directly life threatening, but the oxygen deprevation of the downstream brain tissue can lead to irreversible cell death. The subsequent tissue response to the blood pooling and occasional clotting can lead to additional damage to neighboring areas of the brain.

http://www.mayfieldclinic.com/PE-sah.HTM

CT scans can be used to detect the pooling of blood following rupture of an aneurysm (the event is called a 'subarachnoid hemorrhage'). In the figure below the aneurysm was located in the middle cerebral artery marked by the asymmetric white areas.

Basavaraj V. Ghodke, M.D. , Danial K. Hallam, M.D., M.Sc. , Louis J Kim, M.D. , Laligam Natarajan Sekhar, M.D. (http://www.uwmedicine.org/patient-care/our-services/medical-services/stroke-center/pages/articleview.aspx?subid=83&P=1)

How is it treated? (from webmd)

"The following surgeries are used to treat both ruptured and unruptured brain aneurysms:

  • Coil embolization. During this procedure, a small tube is inserted into the affected artery and positioned near the aneurysm. Tiny metal coils are then moved through the tube into the aneurysm, relieving pressure on the aneurysm and making it less likely to rupture. This procedure is less invasive and is believed to be safer than surgical clipping, although it may not be as effective at reducing the risk of a later rupture. It should be done in a large hospital where many such procedures are done.

  • Surgical clipping. This surgery involves placing a small metal clip around the base of the aneurysm to isolate it from normal blood circulation. This decreases the pressure on the aneurysm and prevents it from rupturing. Whether this surgery can be done depends on the location of the aneurysm, its size, and your general health.

Aneurysms that have bled are very serious and in many cases lead to death or disability. Management includes hospitalization, intensive care to relieve pressure in the brain and maintain breathing and vital functions, and treatment to prevent rebleeding."

Note: italics were added by instructor: please examine the italicized statement critically.

A Guglielmi detachable coil, or GDC, is a device first used in intracranial non-invasive surgery to treat brain aneurysms. It was invented by Italian interventional neuroradiologist Dr. Guido Guglielmi in 1990, and was gradually introduced in the later 1990s as an alternative to surgery. In aneurysms that are not surgically accessible a specialized catheter is used to place a platinum coil in the bulge of the artery wall. The lodgment of the coil is intended to stabilize the aneurysm and prevent further expansion of the bulge in the wall. Localized thrombosis is thought to contribute to the 'resolution' of the aneurysm, though other healing mechanisms may be important.

The long-term efficacy of GDC coils and similar coils in the treatment of cerebral aneurysms is still being studied.

Specific Clinical Case (NEJM, 2006)

The patient described below was a complex case in which a combination of treatments were used to stabilize the aneurysm.

[this is pretty dense reading] full article: http://www.nejm.org/doi/full/10.1056/NEJMra052760

Figure: http://www.nejm.org/doi/full/10.1056/NEJMra052760

Figure: Stent-Assisted Re-Coiling after Recurrence of an Aneurysm Initially Treated with Coiling. Panel A (three-dimensional rotational catheter angiogram) and Panel B (left carotid injection, two-dimensional catheter angiogram, oblique view) show an aneurysm of the posterior communicating artery (Panel B, arrow). Panel C (two-dimensional catheter angiogram, lateral view) shows the successful coiling of the aneurysm (arrow); this was followed eight months later with marked coil compaction and recanalization of the aneurysm (Panel D, two-dimensional catheter angiogram, lateral view). Panel E (two-dimensional catheter angiogram, lateral view) shows successful re-coiling of the aneurysm with the assistance of a stent (too small to visualize). Panel F shows the configuration used for the stent and the coil.

Questions to guide preparation

Brief case summary

  1. Problem

  2. Intervention

  3. Outcome – consider not only this case, but also what is the outcome in a statistically averaged sense?

History of the intervention

  1. Have intravascular delivered coils been used previously to the implementation of the GDC technology?

  2. What company got the first patent on the GDC?

  3. Who first used a GDC in human surgery?

Composition and manufacture of the GDC and related coil types

  1. Material(s) used in their manufacture

  2. Physical, mechanical, and chemical properties that are relevant to this treatment.

  3. Consider also (but with less emphasis) the composition and manufacture of the delivery system.

Short and long-term biological response

  1. How does the aneurysm respond to the coil in the short- and long-term?

  2. What adverse tissue and thrombotic reactions are possible?

  3. What positive tissue and thrombotic reactions are possible?

  4. What categories of aneurysms exist in the brain and what are best suited for treatment with current coil designs?

Limitations of the GDC as therapy and opportunities for improvement

  1. How does the underlying material differ from coronary stents?

  2. What repair process might be enhanced to improve stabilization of the aneurysm?

  3. What is the optimal outcome?

  4. What is the typical outcome?

DMU Timestamp: October 22, 2013 11:06





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