Endovascular Thrombectomy: An Important Advancement in Stroke Treatment
Post on 13/10/16
The procedure has a higher rate of success than earlier treatments such as rTPA, and sees about 60% of patients returning to independence within 3 months. Dr Tu Tian Ming explains.
In 2015, a new treatment option for ischemic stroke was announced to the world: Endovascular thrombectomy using second-generation stent retrievers. It was the most important advancement in the field of acute ischemic stroke treatment in the last twenty years, with its efficacy, as an add-on treatment to thrombolysis, being confirmed by 5 separate clinical trials1. The success was a collaborative effort made possible by thousands of clinical stroke researchers across 89 international sites. This treatment option has since been incorporated into clinical guidelines in both United States and Europe2, and is also already available at all major public hospitals in Singapore.
Ischemic stroke is a life threatening condition where the one of the blood vessel leading into the brain is blocked by a blood clot. This obstruction results in disruption to blood flow and causes subsequent damage to the brain due to lack of oxygen supply and glucose delivery. The longer the duration of the occlusion, the more damage the brain suffers. Time is Brain! Hence the faster the occlusion is resolved, the more brain is saved.
Endovascular thrombectomy is a radiological procedure, whereby a doctor inserts a flexible wire through an artery in the groin, directing it to the vessel where the blood clot resides. He will then deploy a metal stent to the site of the blood clot, enabling him to remove the clot by pulling the stent back towards the groin. This procedure is usually performed with the patient awake but with anesthesia applied at the groin. The duration of the procedure may range from an hour to 3 hours depending on the extent of the clot.
Since 1995, the only established treatment available for acute ischemic stroke has been intravenous thrombolysis3. It acts as a clot-buster to dissolve the clot that has obstructed the blood vessel to the brain. The intravenous medication, called recombinant tissue plasminogen activator (rTPA), can be only given within 4.5 hours from onset of symptoms of stroke. Moreover, an urgent brain scan, to rule out bleeding within the brain, is required prior to its administration. The overall success of this treatment to dissolve the clot is only about 30%4 but it was the best we had for a long time. Despite it being the only treatment available, only 5% of all stroke patients actually receive the treatment5 in the real world and the major reason is due to delay of presentation of the patient at the hospital from onset of symptoms6.
The new treatment option of endovascular thrombectomy, which is given in addition to rTPA, will extend the time interval for treatment to 6 hours. In addition, the success of this new treatment is also higher than rTPA alone, with approximately 60% of patients returning to independence of activity at 3 months. However, the procedure is not without risk. Being an invasive procedure that requires the puncturing of a major artery, bleeding is the most common adverse effect. There is also a small (1%) but serious risk of death related to the procedure.
It must be noted that not all ischemic stroke patients qualify for endovascular thrombectomy as this new treatment option has its own set of stringent criteria. The criteria exist to help the doctor decide which patient will benefit most from the treatment. The patient must be evaluated through a specialized x-ray test to determine the presence and the position of blood clot. In addition, endovascular therapy is still an “add-on” to rTPA treatment, hence all ischemic stroke patients will still be offered and treated with rTPA as a first-line treatment.
In conclusion, endovascular thrombectomy is a new treatment option already available to ischemic stroke patients in Singapore. Early presentation to emergency health services is still critical to prevent any delay in treatment.
Dr Tu Tian Ming is a neurologist with the National Neuroscience Institute, with subspecialties in stroke and neurointensive care.
- Saver JL, Goyal M, van der Lugt A, Menon BK, Majoie CB, Dippel DW, et al. Time to treatment with endovascular thrombectomy and outcomes from ischemic stroke: A meta-analysis. Jama. 2016;316:1279-1288
- Powers WJ, Derdeyn CP, Biller J, Coffey CS, Hoh BL, Jauch EC, et al. 2015 american heart association/american stroke association focused update of the 2013 guidelines for the early management of patients with acute ischemic stroke regarding endovascular treatment: A guideline for healthcare professionals from the american heart association/american stroke association. Stroke; a journal of cerebral circulation. 2015;46:3020-3035
- Tissue plasminogen activator for acute ischemic stroke. The national institute of neurological disorders and stroke rt-pa stroke study group. The New England journal of medicine. 1995;333:1581-1587
- Bhatia R, Hill MD, Shobha N, Menon B, Bal S, Kochar P, et al. Low rates of acute recanalization with intravenous recombinant tissue plasminogen activator in ischemic stroke: Real-world experience and a call for action. Stroke; a journal of cerebral circulation. 2010;41:2254-2258
- Fonarow GC, Smith EE, Saver JL, Reeves MJ, Bhatt DL, Grau-Sepulveda MV, et al. Timeliness of tissue-type plasminogen activator therapy in acute ischemic stroke: Patient characteristics, hospital factors, and outcomes associated with door-to-needle times within 60 minutes. Circulation. 2011;123:750-758
- Tong D, Reeves MJ, Hernandez AF, Zhao X, Olson DM, Fonarow GC, et al. Times from symptom onset to hospital arrival in the get with the guidelines–stroke program 2002 to 2009: Temporal trends and implications. Stroke; a journal of cerebral circulation. 2012;43:1912-1917
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