Removal of the clot causing a severe stroke, in combination with the standard medication, improves the restoration of blood flow to the brain and may result in better long term outcomes, a new study has found.
"These findings are a game-changer for how we should treat certain types of stroke," said Dr Demetrius Lopes, surgical director of the comprehensive stroke center at Rush University Medical Center and a co-author of the study.
"These outcomes are the difference between patients being able to care for themselves after stroke and being dependent," Lopes said.
The findings of the Swift Prime trial (Solitaire With the Intention For Thrombectomy as PRIMary Endovascular treatment) are published in the New England Journal of Medicine.
The standard treatment for ischemic stroke within the first three to four and a half hours of symptoms is intravenous tissue plasminogen activator (IV tPA), a medication which dissolves the clot.
During thrombectomy, a neurovascular surgeon threads a catheter through an incision in the patient's groin, snaking it through the blood vessels and into the brain.
The doctor then uses a device attached to the catheter to grab and dislodge the clot and pull it all the way out through the incision.
IV tPA currently is the only treatment for ischemic stroke approved by the US Food and Drug Administration, but the use of thrombectomy is allowed in clinical trials.
The Swift Prime study randomly divided patients with severe ischemic strokes into two groups, one receiving IV tPA alone, and the other receiving combination therapy of IV tPA and thrombectomy within six hours of the onset of stroke symptoms.
In all, 196 patients - 98 in each group - at 39 centres in the US and Canada participated in the study between December 2012 and November 2014.
The researchers assessed each patient's level of disability after 90 days using a standardised measurement.
The study found that the patients who received IV tPA plus thrombectomy exhibited reduced disability across the entire range of the measurement, with a functional independence rate of 60 per cent compared to 35.5 per cent for those patients who received only IV tPA.
"For every 2.6 patients treated, one additional patient had an improved disability outcome; for every four patients treated, one additional patient was independent at 90 day follow-up," the researchers said.
The study also found that patients who received thrombectomy had better cerebral blood flow rates: At 27 hours after treatment, 82.8 per cent of those patients had blood flow that was 90 per cent of normal or better, versus 40.4 per cent of patients who only received IV tPA.
