SAN ANTONIO - Doctors are learning how to snake threadlike catheters deep into the brains of stroke patients and release clot-dissolving drugs directly into the blood clots that are choking off brain functions.

In a number of small studies dotted around the country, patients who normally would die or survive with severe neurological deficits have left the hospital walking, talking and able to resume their normal lives.

``This is still considered experimental, but the results are very encouraging,'' said Dr. David Barr, director of interventional neuroradiology at Baptist Memorial Hospital in Memphis, Tenn., who presented the findings from his latest study in San Antonio this week. His study indicated the technique could double the time window that doctors have in which to administer the crucial clot-busting drugs.

Barr used reteplase, a newer version of the better-known clot-busting drug TPA, or tissue plasminogen activator. Reteplase has been approved to treat heart attacks and is now being tested in stroke patients.

Barr's study was discussed at the annual scientific meeting of the Society of Cardiovascular and Interventional Radiologists in San Antonio.

Intravenous TPA, infused through the arm, is now a common stroke treatment. But the time window for saving the brain is small - patients must get to the hospital, get diagnosed and treated within three hours.

Barr's study involved nine patients with large clots whose prognosis typically would be poor. Doctors threaded a catheter from the groin area and into the brain, where they administered reteplase directly into the clot.

One patient died and two others had poor recoveries. But six patients had what doctors considered a very good recovery, even some who got the drugs nearly six hours after the stroke onset.

``Three had a complete or nearly complete return to normalcy,'' Barr said. ``The other three still have problems, but they still improved significantly so that they can live independently and function rather well.''

Equally significant, Barr noted, was that the treatment worked in patients who took a long time to get to the hospital.

Studies elsewhere have produced similar results, American Stroke Association spokesman Dr. Arthur Pancioli said. But providing the same standard of treatment for every stroke patient will be difficult because of the high skill level and advanced technology required, he added.

``You've got to get to a place that very few people can go with wires and catheters, and you have to get there both quickly and accurately,'' said Pancioli, vice chairman of emergency medicine at the University of Cincinnati Medical Center in Ohio.

• More news on Stroke

Related MEDLINEplus Pages:

• Stroke