Mark N Rubin, MD
Luby M, Warach SJ, Nadareishvili Z, and Merino JG. Immediate Changes in Stroke Lesion Volumes Post Thrombolysis Predict Clinical Outcome. Stroke. 2014
Mr. Berrawas right when he said “it’s tough to make predictions, especially about the future.” This is especially true in acute stroke practice, when all involved want to know exactly how things will go in the short, medium and long-term. However, in that individual patients frequently do not fit cleanly into our myriad risk scores because of the many, many moving parts in the cerebrovascular risk machine, the estimation power of combined clinical experience and risk stratification tools is imperfect.
The investigators of a recent study, as a substudy of a larger observational project, seek to augment our predictive powers with neuroimaging. This substudy was of patients presenting with acute stroke who were able to undergo acute multimodal MRI prior to intervention and then subsequent multimodal MRI scans at 2 and 24 hours post-intervention. These patients were then tracked for functional outcome out to at least three months, and the investigators went back to see which, if any, neuroimaging findings during that physiologically and clinically dynamic period were associated with a favorable outcome (e.g., modified Rankin score of 0-1, which basically means “functional independence”). Overall, in brief, binary multiple logistic regression analysis yielded younger age (per year decrease, OR=1.102, p=0.005, 95% CI: 1.03-1.18), admit NIHSS (per point decrease, OR=1.136, p=0.02, 95% CI: 1.020-1.264) and decrease in DWI volume at 24 hours (OR=1.126, p=0.008, 95% CI: 1.032-1.23) as significant predictors of favorable clinical outcome.
To complement the many studies that suggest DWI reversal with or without acute reperfusion therapy at some point in time during the early phase of acute stroke portends a good outcome for the patient, this investigation gives comprehensive, sequential, multimodal neuroimaging features that support a rational conclusion: if early reperfusion of ischemic tissue is achieved and sustained, less brain is injured and the patient does better.
Multimodal MRI is fascinating and provides valuable information to guide acute stroke therapy and prognostication, but is not widely available. Furthermore, only very few centers have the expertise to perform acute MRI before treatment without unnecessarily delaying systemic thrombolysis. All that being the case, this study should be read with an eye toward the principle of achieving and maintaining early reperfusion rather than implementation of multimodal MRI into pre-treatment acute stroke practice.