Stroke Rounds: Lesion Site Affects Reperfusion Benefit With Clot Grabber

If the ICA is blocked is it even a stroke since that is prior to entering the Circle of Willis? And if the Circle of Willis is complete then that wouldn't cause problems. Is this problem even defined correctly?
http://www.medpagetoday.com/Cardiology/Strokes/55888?xid=nl_mpt_cardiodaily_2016-01-28&eun=gd3r
The magnitude of functional outcome benefits from reperfusion with endovascular thrombectomy may depend on the site of occlusion, a meta-analysis showed.
Reperfusion was associated with 3.5-fold higher odds of a good functional outcome (0-2 on the modified Rankin Scale) at 90 days among patients with internal carotid artery (ICA) occlusions and 6.2-fold higher among those with proximal middle cerebral artery (MCA) occlusions versus persistent occlusion.
Reperfusion had no significant association with good functional outcome in distal MCA lesions (OR 1.4, 95% confidence interval 0.8-2.6), although there was a link in the M2 occlusion subset (OR 2.2, 95% CI 1.0-4.7), Robin Lemmens, MD, PhD, of University Hospitals Leuven in Belgium, and colleagues reported online in Neurology.
"The association between reperfusion and good clinical outcomes is stronger in patients with proximal(closer) occlusions compared to distal(farther) occlusions," the group concluded. "Our results, however, do not indicate that patients with distal MCA occlusions do not benefit from endovascular therapy."
"In contrast, the results underscore the need for additional clinical trial data to determine the effect of endovascular therapy in this subgroup," they continued.
Indeed, the study "is not going to change my practice," Haitham Dababneh, MD, of Doctors Hospital at Renaissance in Edinburg, Texas, told MedPage Today. He likewise called for better data from randomized controlled trials, noting differing baseline characteristics between groups in the meta-analysis and the fact that there were fewer patients with distal strokes than proximal strokes.
For now, "it's hard to compare apples to oranges," Dababneh said.
As for the reason why patients with distal MCA occlusions might show less benefit from reperfusion, the authors suggested that those individuals "have less brain tissue at risk of infarction (i.e., less brain tissue that can be salvaged with reperfusion) compared to patients with more proximal MCA or ICA occlusions."
Lemmens and colleagues pooled patient-level data from four large endovascular trials -- SWIFT, STAR, DEFUSE 2, and IMS III -- for a total of 710 patients in their analysis.
Panagiotis Papanagiotou, MD, of Hospitals Bremen-Mitte in Germany, told MedPage Today that clinicians should focus on careful patient selection, perhaps with advanced imaging techniques.
Papanagiotou, who was an investigator for SWIFT, added that the improvement of endovascular techniques -- such as "direct thrombus aspiration to achieve higher recanalization rates" -- may also be helpful for the treatment of distal lesions.