The year 2012 was dark times for endovascular treatment for acute ischemic stroke. MR-RESCUE, IMS-3, and SYNTHESIS were all decidedly negative, and their failures trotted out in the New England Journal of Medicine.
This current year has been much better – a trove of trials following the initial positive result of MR-CLEAN, the key features of which were:
- Improved time from onset to endovascular intervention.
- Effective recanalization, far exceeding that of tPA.
- Narrowly selected patients guided by imaging criteria.
Of those three key features, it appears the universally critical items are primarily the last two – recanalization and salvageable tissue.
This is a reanalysis of IMS-3, looking retrospectively at 78 patients from the trial for whom cerebral angiograms were available. They looked specifically a the “capillary index score”, essentially, an imaging-based classification of the collateral circulation near a lesion. In an outcomes-blinded fashion, the authors calculated the CIS for each, and then correlated the results with functional outcomes. The numbers are small, but the numbers achieving good outcomes are consistent and logical:
- Poor CIS, unsuccessful recanalization: 1/15 (7%)
- Poor CIS, successful recanalization: 2/15 (13%)
- Good CIS, unsuccessful recanalization: 5/24 (25%)
- Good CIS, successful recanalization: 17/24 (71%)
Essentially another brick in the small wall of evidence favoring the necessity of an imaging-based strategy to narrowly select patients for endovascular intervention, rather than a non-selected time-based strategy.
“Relative Influence of Capillary Index Score, Revascularization, and Time on Stroke Outcomes From the Interventional Management of Stroke III Trial”
http://www.ncbi.nlm.nih.gov/pubmed/25953374