NEW ORLEANS – Improving the outcomes of endovascular stroke intervention lies – at least in part – in selecting the best candidates.
But even those who are at the highest risk of harm from the treatment still may reap some benefit when compared with the grim alternative, researchers said at the International Stroke Conference, which was sponsored by the American Heart Association.
The oldest patients and those with large ischemic infarcts are at exceedingly high risk of very poor outcomes with mechanical embolectomy, according to Dr. Albert Yoo and Dr. Yogesh Moradiya. But their analyses of stroke study cohorts indicate that clinicians might be able to predict and screen for patients who will benefit most from endovascular stroke treatment.
Patients with the lowest scores on the ASPECTS (Alberta Stroke Program Early CT Score) assessment are known to have "dismal outcomes, and should probably be excluded from this therapy," said Dr. Yoo, a vascular radiologist at Massachusetts General Hospital, Boston. But, he said, his analysis identified a subgroup of patients he now believes should be treated, despite their prior reputation as barely salvageable.
"If you take the wrong person, and the procedure goes bad and they die on the table, this is not helping the brain."
In the prediction of outcome by ASPECTS, patients with ischemic stroke are grouped by the size of their initial infarct, as seen on noncontrast CT scan. The 10-point score has conventionally dichotomized patients into those destined to have poor outcomes (ASPECTS 0-7) and those with much better outcomes (APSECTS 8-10).
Dr. Yoo examined outcomes in two stroke study cohorts that used ASPECTS as a predictor of outcome. The pooled analysis included 215 patients with a mean age of 66 years. Their mean National Institutes of Health Stroke Scale score was 17. Most of the strokes (77%) were in the middle cerebral artery.
The pretreatment ASPECTS score was 0-4 in 16% of patients, 5-7 in 34%, and 8-10 in the remainder. The median ASPECTS score was 7, which is the widely accepted cutoff level for using mechanical embolectomy with a reasonable hope of good outcome.
The procedure was successful in most patients, with 83% achieving a TIMI (thrombolysis in myocardial infarction) score of 2 or 3. Most of the reperfusions occurred in a timely manner as well (within 6 hours for 27% and shortly thereafter for the rest).
Dr. Yoo said that, generally, those with the lowest scores on ASPECTS fared significantly worse, as expected. In the conventional split, 24% of those with scores of 0-7 had a good 90-day outcome (defined as discharge home with self-care), compared with 44% of those with scores of 8-10. Time to reperfusion did not affect outcomes in the lower-scoring group. The patients who reperfused early had almost exactly the same poor outcome as did those who reperfused late and those who never received the intervention.
But when Dr. Yoo split the scores of the cohorts into three groups, he found that the vast majority of poor outcomes occurred in the 0- to 4-point range. Among these patients, only 4% had good outcomes, and no one in the 0- to 3-point group had a good outcome.
Patients who had a score of 5, 6, or 7 points on ASPECTS, however, fared significantly better, with good outcomes in about 20%, 30%, and 40%, respectively. Time to reperfusion was important in these patients: Outcomes were good in 53% of early reperfusions, 31% of late reperfusions, and 20% of those who were not reperfused.
The results for patients with 8-10 points on ASPECTS – generally considered the group most likely to benefit – were similar to those seen in the 5- to 7-point group. Good outcomes occurred in 54% of those in the 8- to 10-point group with early perfusion. The rates were 46% in those with later reperfusions and 17% in those with no reperfusion.
When Dr. Yoo combined patients with 5-7 points and 8-10 points on ASPECTS, the outcomes still looked positive. "Almost all [85%] of the patients in these groups who achieved a TIMI 2-3 reperfusion had good outcomes," he said. This was a threefold increase over similar patients with a TIMI score of 0-1.
"The ASPECTS score does identify a group of patients highly likely to have dismal outcomes who probably will not benefit from reperfusion therapy and should be excluded from it," he said. "But patients with ASPECTS scores of 5-7 do appear to benefit, and treatment should not be withheld from this group."
Age as the determining factor of who should undergo reperfusion therapy proved a tougher sell for Dr. Yogesh Moradiya, a neurology fellow at the SUNY Downstate Medical Center, Brooklyn, N.Y.