Recanalization Effective Even in Anterior Stroke Patients with Large Lesions

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Acute ischemic stroke patients may still benefit from endovascular therapy even when they have large lesions on diffusion-weighted magnetic resonance imaging (DWI), according to a paper published online June 11, 2013, ahead of print in Stroke. 

Investigators led by Mikael Mazighi, MD, PhD, of Bichat University Hospital (Paris, France), analyzed prospective registry data on 139 acute stroke patients with complete occlusion of the internal carotid or middle cerebral artery who received endovascular therapy between April 2007 and November 2011. Endovascular therapy consisted of recombinant tissue plasminogen activator (tPA), given intravenously to eligible patients and intra-arterially if necessary. In the absence of recanalization after tPA, patients underwent additional mechanical endovascular therapy using either the snare or the Solitaire devices.   

Patients had a median lesion volume of 14 cc (interquartile range [IQR], 5-43 minutes) when measured at a median of 110 minutes (IQR, 77-178 minutes) from symptom onset. Five patients (4%) showed no lesion on DWI. Larger lesions (> 32 cc) tended to be located in the internal carotid artery and patients with such lesions were more apt to be treated by direct endovascular treatment and to be younger. Lesion volume progressively rose alongside National Institute of Health Stroke Scale (NIHSS) score at baseline (P < 0.001).   

When patients were separated into tertiles according to baseline DWI lesion volume, those with larger lesions had poorer clinical outcome (defined as modified Rankin Scale [mRS] score 0-2 at 90 days) and higher rates of intracerebral hemorrhage and 90-day mortality (table 1).   

Table 1. Clinical Outcomes by Lesion Volume

  
Logistic regression analysis that adjusted for age, time from symptom onset to imaging, prior IV tPA, internal carotid artery occlusion, and admission NIHSS score found an association between higher volume and less favorable outcome (adjusted OR 0.55; 95% CI 0.31-0.96). 

Complete recanalization was achieved in 65 patients (47%) at a median of 238 minutes (IQR, 206-285 minutes). Compared with patients who had TIMI flow 0-2 after treatment, patients with TIMI 3 flow tended to have better outcomes, though not all differences reached significance (table 2).   

Table 2. Clinical Outcomes by Complete Recanalization

  
Among the 19 patients with volumes greater than 70 cc, complete recanalization significantly reduced mortality (P = 0.045) but did not increase the rate of favorable outcome (P = 0.12) or decrease the rate of intracerebral hemorrhage (P = 0.62). 

Overall, multivariable adjustment showed complete recanalization to be associated with more favorable outcome compared with no or partial recanalization (adjusted OR 6.32; 95% CI 2.90-13.78). Unadjusted analyses showed that complete recanalization had similarly positive impact on both of the 2 upper tertiles of DWI volume (P < 0.005). 

DWI Has a Role in Clinical Practice

“These original findings suggest that the occurrence of a complete recanalization significantly alters the outcome despite a large DWI lesion,” Dr. Mazighi and colleagues conclude, specifying that “additional studies are needed at this early time point to define which patients with a very large ischemic lesion on DWI may benefit from endovascular treatment. In the meantime, a cautious case by case selection is strongly recommended.”   

The lack of effect seen in patients with smaller volumes can be attributed to low statistical power, they stress.   

In a telephone interview with TCTMD, Lee R. Guterman, MD, PhD, of the Buffalo Neurosurgery Group (Buffalo, NY), described the study as one of the best he has seen using DWI to document acute stroke volume. “This is a really good paper, and it took me 2 or 3 reads to really understand [its complexity].”   

The evidence linking DWI volume and recanalization to outcome, even in large lesions, is new, Dr. Guterman confirmed. Moreover, he added, “in moderate strokes, their recanalization rates and outcomes were excellent.” 

Although DWI is well-regarded, logistical concerns have complicated its use in routine practice, he explained. It “takes longer and is much more sensitive to motion artifact. You have to have a special ventilator if the patient is intubated. . . . It slows down the acute stroke treatment process,” Dr. Guterman said.   

Based on the current study, he reported being inspired to start his own trial specifically employing this technique. “It’s time for all of us to consider incorporating [DWI] and volume analysis into our acute stroke therapy,” Dr. Guterman advised.   

Large lesion volume alone does not preclude endovascular therapy, he concluded, adding that patient selection should factor in age, comorbidities including dementia, and pre-stroke activity level.   

  

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Source:
Olivot J-M, Mosimann PJ, Labreuche J, et al. Impact of diffusion-weighted imaging lesion volume on the success of endovascular reperfusion therapy. Stroke. 2013;Epub ahead of print. 

  

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