Stroke Centers - All About Interventional Radiology!
The following passages are excerpted from “Interventional Quarter,” issue 2, July 2010.
Click here to go to the actual issue.
People need to be aware of their options. Today, we have vastly improved stroke treatment options compared to 30, 20 or even 10 years ago. I am amazed at the techniques and technology that is currently available. With continued education, stroke awareness has become much more widespread. Treatment options continue to improve. Remember, speed is of the essence. The window for treatment of a stroke is within SIX hours from TIME OF ONSET of symptoms.
The medical affliction of stroke has been known for almost 2,500 years, being described by Hippocrates (then called apoplexy). However, all that was known until recently were the symptoms - the sudden onset of paralysis. The cause and the cure remained outside the influence of medicine for many, many centuries. Therapy has only become available in recent years as doctors discovered more about the causes and mechanisms of stroke. Currently, many stroke patients can experience no or few disabilities - provided they get treated promptly.
According to the WHO, stroke is the leading cause of long-term disability worldwide, as well as being the second most important cause of cognitive impairment after Alzheimer’s disease. This can have a terrible effect on the quality of life of the affected individual and their families, and results in massive healthcare and pension costs. It is also the third greatest cause of death worldwide, after coronary heart disease and cancer1. But far from being untreatable, a substantial body of evidence has established the efficacy of various strategies for the prevention and treatment of stroke.
Ischemic stroke is caused by a blockage of blood vessels which irrigate the brain, and accounts for 80% of strokes. Ischemic stroke can result from different causes, but large artery atherosclerosis is generally the most frequent cause. Ischemic stroke affects both a core area and the surrounding tissue (penumbra). The core area is usually damaged irreparably, but the penumbra can often be salvaged, if blood supply is re-established in time. Saving this tissue is the focus of most treatments.
Risk factors for stroke are either non-modifiable (age, sex, race/ethnicity, family history) or modifiable. Modifiable factors include cigarette smoking, arterial hypertension, diabetes mellitus, hypercholesterolemia, obesity, contraceptive pill or hormone replacement therapy, atrial fibrillation and other cardiac diseases, and stenosis and occlusion of cerebral arteries.
Accordingly, the Face Arm Speech Test (FAST) is a simple way to recognize if someone has suffered a stroke or TIA. Any of these signs can indicate stroke:
- Face: Mouth or eye drooping, inability to smile normally
- Arms: Weakness, inability to raise both arms properly
- Speech: Slurred or unintelligible speech, inability to understand speech of others
➡ Time to call the emergency services
The most important thing when faced with stroke or TIA is to seek urgent medical attention. The longer the brain is deprived of oxygen, the less chance that the brain will survive unharmed.
As the experts say, “time is brain” - up to 2 million brain cells can die every minute that oxygen perfusion is cut off.
Thrombolytic drugs (tissue plasminogen activator or t-PA) can often dissolve a clot, returning blood flow to normal. Studies have shown that intravenous thrombolysis (IVT) given within 4.5 hours of symptom onset is beneficial in selected stroke patients. This medication carries a slight risk of symptomatic hemorrhage (about 5% in routine clinical practice), but used correctly by experienced doctors, the benefits usually outweigh the risks.
This 4.5-hour window can be extended up to 6 hours by intra-arterial thrombolysis (IAT) or up to 8 hours by mechanical thrombectomy (MT), performed by an interventional radiologist. IAT uses a catheter to deliver the drugs directly to the clot site. Many centers also use "bridging" - a two-step thrombolytic treatment where the first dose is delivered intravenously and the remaining one intra-arterially.
Why IR is gaining ground
According to current WHO data, between 1981 and 2001, the number of minimally invasive preventative stroke treatments performed increased steadily, while surgical treatment numbers remained constant or declined. This clearly shows the growing importance of interventional treatments in stroke therapy. Given that there has been a phenomenal increase in the number of dedicated stroke units since this data was collected, it can only be assumed that this trend has continued even more steeply.
Dedicated stroke units
With increased patient volumes, hospitals are in a position to dedicate resources to this patient population. Many hospitals are establishing dedicated stroke units, which adhere to increasingly uniform treatment protocols and standards for ensuring swift and suitable treatment.
In larger hospitals with appropriate interventional radiology staffing arrangements, IR techniques such as intra-arterial thrombolysis and thrombectomy can be offered on a 24-hour basis. However, both in terms of availability of staff, and in terms of quality standards and costs, it is not feasible to offer the full range of available treatments in every hospital.
It goes without saying that patient outcomes improve in centers that are capable of achieving a case volume that ensures a threshold level of technical and clinical experience.
Of the total number of stroke patients who present to a stroke centre for acute therapy, an estimated 10-20% requires IR intervention.
Some of these treatments may be costly, but the bottom line is that stroke treatment is nearly always a money-saving venture. Without treatment, patients who are lucky enough to survive their stroke inevitably face some degree of disability.
Minimally invasive stroke treatment options provide both patient and health provider with opportunities that could not have been dreamed of 30 years ago. Incorporating their potential into the range of treatments made available to patients is essential if the burden of stroke is to be countered and reduced. Advances in medicine are continually offering patients new options, and interventional radiology is certainly playing its part.
Websites of interest:
www.strokeassociation.org (American Stroke Association/US)
www.stroke.org.uk (The Stroke Association/UK)
www.irishheart.ie (Irish Heart Foundation/IE)
www.world-stroke.org (World Stroke Organisation/WSO)
www.eso-stroke.org (European Stroke Organisation/ESO)
www.safestroke.org (Stroke Alliance for Europe/SAFE)