The Source for Neurovascular News and Education

June 17, 2019

 

Absence of collateralization makes the brain particularly vulnerable to reperfusion delay, investigators suggest.

 

 

Among patients with occlusions of the middle cerebral artery (MCA), involvement of the striatocapsular region could imply that rapid recanalization is especially important, according to data stemming from a German/Swiss collaboration. The lack of collateralization in this region, researchers say, may mean that cell death occurs more rapidly with increasing time to reperfusion.

Time dependency of endovascular therapy outcomes in acute ischemic stroke “may vary substantially according to the site of occlusion and the degree of collateralization,” investigators led by Dennis M Hedderich, MD (Technical University of Munich, Germany), write. They point out that the MCA “territory consists of different vascular supply zones—namely, a well-collateralized cortical and peripheral white matter zone and a poorly collateralized end artery territory in the striatocapsular region supplied by the MCA lenticulostriate arteries.”

As a result, they hypothesize, occlusions in the striatocapsular region may be particularly vulnerable to treatment delays.

To test their idea, the authors matched 97 patients whose MCA occlusions had involvement of the striatocapsular region and 97 patients whose MCA occlusions did not involve that territory based on their symptom onset to reperfusion interval (SORT). All patients were treated endovascularly between January 2007 and June 2016 and achieved substantial reperfusion, defined as TICI ≥ 2a. The findings were published online recently in the Journal of NeuroInterventional Surgery.

Patients without striatocapsular region involvement were older (median 75.8 vs. 72.8, P = 0.024) and had lower NIHSS scores on admission (13 vs. 15, P < 0.001). On the day of discharge, they also tended to have lower NIHSS (P = 0.191) and mRS (P = 0.099) scores.

Multivariate analysis revealed a stronger correlation between both discharge NIHSS score and discharge mRS score and SORT for patients with involvement of the striatocapsular region, compared to those without.

 

Correlation Between SORT and Striatocapsular Region Involvement

 

With Involvement

(n = 97)

Without Involvement

(n = 97)

Discharge NIHSS (ƿ)

0.447

0.234

Change in NIHSS (ƿ)

- 0.396

−0.246

Discharge mRS (ƿ)

0.551

0.292

 

In addition, the interaction of striatocapsular region involvement and SORT was significant for both of these endpoints.

 

May Help Guide Patient Selection

The authors acknowledged that this is an “exploratory, hypothesis-generating, retrospective, single-center study,” with all its associated limitations. Nevertheless, their findings do suggest that “time dependency of outcome after [endovascular therapy] is more pronounced if parts of the proximal MCA territory are affected,” Hedderich et al say. “This may reflect the lack of collateralization in the striatocapsular region and a more stringent cell death with time. If confirmed, this finding may affect the selection of patients based on different time windows according to the territory at risk.”

 


Source:

Hedderich DM, Boeckh-Behrens T, Friedrich B, et al. Impact of time to endovascular reperfusion on outcome differs according to the involvement of the proximal MCA territory. J NeurInterv Surg. 2017;Epub ahead of print.

 

Disclosures:

Hedderich reports no relevant conflicts of interest.