“For the stroke field, this is a really big deal,” Walter Koroshetz, deputy director of the National Institute of Neurological Disorders and Stroke, said of the findings, which were presented over three days at the International Stroke Conference in Honolulu.
NINDS paid for two of the trials, one of which cost $27 million. One study took eight years to complete because it was so difficult to enroll patients willing to take the chance that they would be randomly assigned to get the older treatment.
Practitioners hoped that “endovascular treatment,” in which a catheter is threaded into a blocked artery and the clot pulled out, would do for stroke patients what it has done for heart attack patients. In them, going after clots with angioplasty balloons and stents is clearly more effective than giving clot-dissolving drugs through a vein in the arm.
“We did this study with the strong expectation that we would find a positive benefit. We were surprised,” said Joseph P. Broderick of the University of Cincinnati Neuroscience Institute, who headed one of the studies.
His view was echoed by Alfonso Ciccone, a neurologist from Milan who led a clinical trial in Italy: “We were surprised. We wanted the superiority of endovascular treatment.”
Whether the findings will cause physicians to abandon the practice is uncertain.
Insurance companies and Medicare, the health insurer for the elderly, already cover the endovascular procedure. It costs about $23,000 compared with $11,000 for acute stroke treatment using intravenous clot-dissolving drugs, known as thrombolytics.
Further, many practitioners think that newer clot-retrieving devices work better than the ones used in the three trials. Because endovascular procedures were shown to be no more dangerous than IV thrombolytics, physicians may continue to perform them and assume the outcomes can only get better.
“Will it change practice? That’s a good question,” said Koroshetz. “The payers may look at this and wonder if they should continue paying for these procedures. If it gets to that point, then clearly things will change.”
Stroke is the fourth-leading cause of death in the United States. About 800,000 people suffer a stroke each year, and about 130,000 die.
Nearly 90 percent of strokes occur when a clot blocks an artery in the brain, starving the region downstream of blood and oxygen. If flow isn’t restored quickly, brain tissue and the functions it controls — movement, speech, cognition — are damaged or can die.
Over the past 20 years, studies showed that if a person having a stroke gets a thrombolytic drug within three hours of when the symptoms start (4½ hours for certain patients), the process can be reversed and a lifetime of disability avoided. Later than that, little is gained; the brain cells are too damaged to survive. In fact, giving the drugs too late can make matters worse. Uncontrolled bleeding can occur as the dying tissue breaks down.