Release Date: July 10, 2003 This content is archived.
One of the biggest challenges in stroke treatment is finding a way to quickly open blocked vessels in the brain without causing hemorrhage or another stroke.
Some blockages respond to intravenous thrombolytics (drugs that thin the blood and dissolve the clot); however, these agents, such as the standard tPA (tissue plasminogen activator), can cause bleeding in the brain, even when given at recommended dosages. Other serious impediments to the drugs are that they must be administered within three hours of stroke onset to be effective, they are active for only 6 to 10 minutes and they aren't recommended for patients who have had a recent surgery.
Minimally invasive therapies such as balloon angioplasty and stenting are used to compress the plaque against the walls of the artery to establish a channel whereby blood flow can be restored; however, this "mechanical" approach increases the chance that fragments of plaque from the clot will break off, migrate to the brain and cause another stroke (see article, opposite).
To overcome these problems, researchers in the University at Buffalo's Department of Neurosurgery are exploring a novel approach that combines the use of thrombolytics with minimally invasive (endovascular) surgery to treat patients with acute ischemic stroke. Results from a prospective trial they conducted, which were reported in the November 2002 issue of Neurosurgery, show that more than one-third (7 of 19) of the patients-all of whom would otherwise have been expected to suffer severe deficits-returned to functional independence.
"If there is a major artery that's blocked, we know from our cardiology colleagues [who treat blocked coronary arteries] that you can sing and dance and squirt drugs in there all you want, but if you don't remove the clot, if you don't reperfuse the heart or brain, the patient won't get better," explains L. N. "Nick" Hopkins, MD, chair and professor of neurosurgery and professor of radiology at UB. "So, we've been working on ways to use drugs that block platelets and dissolve the clot in combination with the mechanical removal of the clot."
In the prospective trial, which was one of the first of its kind in the country, the UB researchers, led by Adnan Qureshi, MD, used a newer, longer-acting thrombolytic agent called reteplase, which they injected directly into the clot through a catheter placed intra-arterially, rather than through an intravenous line. If the drug alone did not reopen the vessel quickly, then mechanical thrombolysis treatment was used to break up the clot.
"This trial opens up new horizons for stroke treatment," says Qureshi, who is now at the University of Medicine and Dentistry of New Jersey. "It shows the feasibility of using both measures in combination to open up the blood vessels and reduce the risk of hemorrhage. None of the 19 patients treated experienced symptoms of brain hemorrhage. The two worked synergistically."
"This pharmaco-mechanical, intra-arterial approach has launched our department into a whole new area of stroke research," adds Hopkins. "Methodologies such as this have the potential to add greatly to what we are doing already."
