Intra-arterial Treatment Outcomes Improve for Basilar Artery Occlusion

Nancy A. Melville

September 08, 2016

Outcomes in stroke patients with acute basilar artery occlusion who are given intra-arterial treatment have improved significantly in recent years, reflecting important advances over outcomes reported with the treatment in older trials, new research suggests.

"Our study is of clinical relevance because it demonstrates that intra-articular treatment is a safe and probably effective treatment for patients with acute stroke due to basilar artery occlusion," coauthor Maarten Uyttenboogaart, MD, PhD, an interventional neurologist at the University Medical Center Groningen, in the Netherlands, tells Medscape Medical News.

"Based on our results and those of other recent cohorts reporting the outcomes of intra-articular treatment with mechanical thrombectomy, we raise the question if further randomized controlled trials are mandatory," he said.

Their findings were published online August 8 in JAMA Neurology.

The study, which the authors describe as one of the largest single-center retrospective analyses to look at outcomes of intra-arterial treatment in patients with acute basilar artery occlusion, involved 38 patients who received the treatment between 2006 and 2015 at the University Medical Center Groningen.

Thirty of the patients received intra-arterial treatment as mechanical thrombectomy, while seven patients received local urokinase without thrombectomy.

Twenty-seven (71%) had been treated with intravenous thrombolysis before intra-arterial therapy.

The patients had a mean age of 58 years; 21 (51%) were male. The median time to intra-arterial treatment was 288 minutes, and patients' median National Institutes of Health Stroke Scale score was 21 points.

Adequate recanalization was reached in 34 of the 38 cases (89%), with functional outcome, defined as a modified Rankin Scale (mRS) score of 0 to 3 at first follow-up at 3 months, shown to be favorable in 19 (50%) patients.

The improvement was substantially greater than the favorable outcome rate of 32% that was reported in the previous Basilar Artery International Cooperation Study (BASICS), which included cases between 2002 and 2007.

Among patients with severe stroke in the new study, 39% had favorable outcomes, compared with only 17% in the intra-arterial group in the BASICS registry.

The improvements seen in the new study likely reflect changes, including better patient selection, the use of intra-arterial therapy in addition to intravenous thrombectomy (which was not included in the BASICS study), and improved treatment techniques using modern stent retrievers, the authors note.

Other differences included that the greater prevalence of embolic stroke and lower occurrence of vessel atherosclerosis in the BASICS registry.

The findings from the new study are meanwhile notably in line with those shown among patients with ischemic stroke of the anterior circulation in the MR CLEAN trial, which was the first randomized clinical trial to demonstrate the effectiveness of thrombectomy among those patients, also showing 50% of patients had favorable outcomes with mRS scores of 0 to 3 after 3 months.

"We were surprised to see that outcome results at 3 months were comparable to the results in the intra-articular group of the MR CLEAN trial, in particular because the natural history of basilar artery occlusion is worse compared to anterior circulation stroke," Dr Uyttenboogaart said.

The new study found no correlation between the status of collateral vessels and outcomes, in contrast to a recent post hoc analysis of the MR CLEAN trial, which showed that the treatment effect of intra-arterial therapy in people with anterior circulation strokes was strongest when collateral vessel status was good at baseline.

"The fact that collateral circulation did not appear to influence functional outcome, which is the case for anterior circulation stroke, was another interesting observation," Dr Uyttenboogaart said.

Two patients (5%) in the new study experienced symptomatic intracranial hemorrhage, which was treated with local urokinase and other pharmacologic therapy.

The 5% complication rate was, again, similar to that seen in the MR CLEAN trial and significantly lower than the 14% reported in the BASICS registry.

"Outcome in endovascular-treated patients with acute basilar artery occlusion in the era of modern thrombectomy devices is better than it was before," the authors conclude.

"Since the natural history of basilar artery occlusion is poor, it may be justified to offer routinely intra-articular treatment in eligible patients, Dr Uyttenboogaart said.

Historic Controls "Fraught With Difficulty"

Commenting on the study, Larry B. Goldstein, MD, professor and chairman of the Department of Neurology and Co-Director of the Kentucky Neuroscience Institute at the University of Kentucky, in Lexington, said he agrees that the treatment approach has evolved in recent years to become effective and commonly used for basilar artery occlusion. Hence, the significant improvement over older data might be expected.

"One thing we've learned over the years is this use of historic controls for these types of comparisons is fraught with difficulty," he told Medscape Medical News.

"The outcomes of patients with these types of abnormalities have improved dramatically over the last few decades, with medical therapy and ICU [intensive care unit] treatments and various other improvements that weren't done a few years ago, so trying to compare with something done 5 to 10 years ago may not be valid."

He added that "the findings are reassuring, but without appropriate contemporaneous controls, it's hard to know what that 50% favorable outcomes really means."

On the other hand, Dr Goldstein agreed that with the risks involved in not treating patients with what is considered the best chance for a good outcome — recommended in American Heart Association guidelines as a reasonable approach — the prospect of a randomized trial seems challenging.

"Most aggressive stroke centers treat patients with basilar artery occlusion this way right now, so it would be a problem to do a randomized controlled trial to prove benefit at this point because we are already fairly convinced that this is a reasonable approach."

Coauthor Reinoud P.H. Bokkers receives support from the Dutch Heart Foundation. No other disclosures were reported. Dr Goldstein has disclosed no relevant financial relationships.

JAMA Neurol. Published August 8, 2016. Abstract

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