Rapid advancements in endovascular interventions have facilitated the use of intracranial endovascular interventions to treat cerebrovascular diseases using minimally invasive intravascular techniques. Developments in computer-aided imaging and high-resolution digital subtraction angiography with reconstruction techniques, as well as easier access to the cerebral vasculature through improved microcatheter design, have lured the interest of physicians across multiple specialties.
Consequently, the increasing popularity of these interventions has led to some controversy regarding who should perform these procedures and the methods of training. Other controversies surround how the efficacy and safety of endovascular procedures compare with standard open procedures. Considering these issues, guidelines have been released by the American Heart Association (AHA) and American Stroke Association (ASA). Published in the April 6, 2009 issue of Circulation, the guidelines examine current information and data about the safety and efficacy of procedures that are used for intracranial endovascular interventional treatment of cerebrovascular diseases (Table 1). They also provide recommendations based on the best available evidence to date.
A Multidisciplinary Approach
AFL may be caused by abnormalities or diseases of the heart as well as diseases elsewhere in the body that affect the heart. These include diseases of the heart valves, especially the mitral valve, and chamber enlargement/hypertrophy. Diseases of the heart that have been linked to AFL include ischemia, atherosclerosis, myocardial infarction, hypertension, and cardiomyopathy. Other diseases/conditions associated with AFL include hyperthyroidism, pulmonary embolism, COPD and emphysema, alcoholism, and stimulant abuse. Some patients with AFL will experience few or no symptoms. For this reason, AFL is often identified incidentally with an electrocardiogram. Other ways to diagnose AFL include cardiac rhythm assessment with outpatient Holter monitoring, event monitors, or more prolonged continuous rhythm monitors.
As the third leading cause of death in the United States, stroke affects over 800,000 people and causes 200,000 deaths annually. “Significant advances in minimally invasive procedures and catheter-based interventions for the treatment of brain blood vessel disease have made these procedures enticing for physicians,” says Philip M. Meyers, MD, FAHA, who chaired the writing committee for the guidelines. “We now have data demonstrating great potential for improved outcomes, shorter recovery time, lower cost, and greater patient satisfaction when treating stroke.”
The perspectives from neuroscience disciplines that span the gamut are included in the AHA/ASA guidelines. They also feature a broad range of experience and expertise on neurovascular disease and treatment. The writing group was composed of neurointerventionalists, neurosurgeons, and neurologists, as well as a vascular medicine specialist and an interventional radiologist. The guidelines then underwent multidisciplinary review by medical and interventional cardiologists, who also had the opportunity to express their perspective and opinions.
“Our goal was to codify the current status of intracranial endovascular cerebrovascular procedures,” says Dr. Meyers. “Currently, we are seeing tremendous interest in and proliferation of these endovascular techniques to treat cerebrovascular disease. This enthusiasm emanates from multiple medical specialties. This is partially due to the potential impact these procedures may have on important causes of disability and death, such as acute stroke. However, many of these techniques remain essentially experimental and require significantly more investigation before they become broadly applied to general medical practice. Consequently, many of these procedures still aren’t reimbursed or have circumscribed indications. For these reasons, a multidisciplinary committee is especially important to weigh the evidence until there is greater scientific proof.”
Guideline Indications & Recommendations
The AHA/ASA guidelines characterize the expected success and complication rates for the most common intracranial endovascular interventional procedures when performed by highly-skilled operators. They should facilitate clinical assessment of the appropriateness, safety, and efficacy of neurovascular procedures for individual operators and institutional programs. The recommendations for their application should be based on current levels of evidence (Table 2).
“The general levels of evidence for many intracranial endovascular cerebrovascular interventions are limited,” explains Dr. Meyers. “The general levels of evidence for many intracranial endovascular cerebrovascular interventions are limited,” explains Dr. Meyers. “For example, the evidence supporting use of endovascular interventions in the setting of acute ischemic stroke is still preliminary.” He adds that use of clot retrieval devices has been approved by the FDA, and there is growing evidence suggesting that retrieving clots may be effective. However, the data are still incomplete, and it is still unproven as to whether or not clot retrieval directly improves clinical outcomes. Similarly, the use of intracranial stents is a viable new approach to treatment of intracranial stenosis, but these devices are still under investigation.
By contrast, one area where the evidence for endovascular intervention has become reasonably well supported by medical evidence is the treatment of ruptured cerebral aneurysms, according to Dr. Meyers. Data comparing the safety and efficacy of endovascular coil occlusion to surgical clipping now support the use of endovascular aneurysm occlusion with platinum micro-coils as a feasible alternative to open surgical clipping in selected cases. These procedures should be performed by appropriately qualified and certified physicians in properly equipped medical centers.
Continuing With Caution
“There is tremendous potential for endovascular interventions to treat complex cerebrovascular diseases,” Dr. Meyers says, “but there are still pros and cons to consider. The AHA/ASA guidelines can be used as a baseline from which we can document the progress and improvement of neurointerventional procedures over time. The hope is that they will help us promote the use of evidence-based medicine over blind enthusiasm so that we can implement these procedures wisely.”
Readings & Resources (click to view)
Meyers PM, Schumacher HC, Higashida RT, et al. Indications for the performance of intracranial endovascular neurointerventional procedures: a scientific statement from the American Heart Association Council on Cardiovascular Radiology and Intervention, Stroke Council, Council on Cardiovascular Surgery and Anesthesia, Interdisciplinary Council on Peripheral Vascular Disease, and Interdisciplinary Council on Quality of Care and Outcomes Research. Circulation. 2009;119:2235-2249.
Meyers PM, Schumacher HC, Higashida RT, et al. Reporting standards for endovascular repair of saccular intracranial cerebral aneurysms. Stroke. 2009;40:e366-e379.
Adams HP Jr, del Zoppo G, Alberts MJ, et al. Guidelines for the early management of adults with ischemic stroke: a guideline from the American Heart Association/American Stroke Association Stroke Council, Clinical Cardiology Council, Cardiovascular Radiology and Intervention Council, and the Atherosclerotic Peripheral Vascular Disease and Quality of Care Outcomes in Research Interdisciplinary Working Groups: the American Academy of Neurology affirms the value of this guideline as an educational tool for neurologists [published corrections appear in Stroke. 2007;38:e38 and 2007;38:e96]. Stroke. 2007;38:1655–1711.
Chimowitz MI, Lynn MJ, Howlett-Smith H, et al. Warfarin-Aspirin Symptomatic Intracranial Disease Trial Investigators. Comparison of warfarin and aspirin for symptomatic intracranial arterial stenosis. N Engl J Med. 2005;352:1305-1316.
Higashida RT, Lahue BJ, Torbey MT, et al. Treatment of unruptured intracranial aneurysms: a nationwide assessment of effectiveness. AJNR Am J Neuroradiol. 2007;28:146-151.