MR CLEAN: Time is Everything

Still basking in the glow of several newly reported studies

confirming that interventional neurology dramatically helps a set of stroke patients, a standing-room crowd of neurologists and other professionals today applauded another presentation on the MR CLEAN trial.

The

American Heart Association/American Stroke Association International Stroke Conference in Nashville, Tenn

logged its highest attendance since it started keep track -- 5,485 people, over 4,300 of them medical professionals.

The main event appeared to be interest in those studies, starting with MR CLEAN,

the seminal Dutch study that had the effect of restoring confidence in the ability of physicians to help stroke patients by mechanically removing clots—in a carefully selected group of patients with major ischemic strokes.

In today’s report at the conference Puck Fransen, MD and colleagues from the Erasmus Medical Center in Rotterdam looked at their MR CLEAN data to examine what effect the amount of time it took to treat and reperfuse the brain tissue had on how well patients did.

Several other studies looking at the same question—whether clot retrieval paired with clot-busting IV tPA is better for patients—were halted when MR CLEAN’s results were announced. At the Nashville meeting, the results of those studies have also been presented. All found a benefit to the dual therapy, and one investigator suggested that maybe physicians could do away with tPA (as yet an untested hypothesis.)

In Fransen’s discussion, she reviewed the MR CLEAN numbers with a focus on how outcomes were related to reperfusion times.

The most important finding, she said, was that there is a 7% downward decline in outcome for every hour a patient’s time from onset of stroke to reperfusion is delayed.

When that time is decreased, “The chances of a good outcome increase rapidly,” she said. Fransen said the study’s 500 patients were included in the new analysis of reperfusion times.

“The absolute effect of treatment was largest in patients with time to reperfusion of less than 5 hours,” she said.The mechanical intervention resulted in a shift patients’ modified Rankin Scale scores, with 14% more patients being independent after their stroke.

Patients with reperfusion after 6 hours likely do not benefit from intra-arterial treatment, she said.

But the main conclusion remains that “The effect of treatment is stronger and chances of reaching independence are better when patients reach reperfusion earlier.

The findings leave many issues to be resolved: will stroke treatment guidelines be changed? If they are, can the health systems in the US and elsewhere get this high-tech procedure to the hinterlands, community hospitals, and medically underserved populations.