Stroke

Key Points:

- Study examines whether lesion growth on DWI predicts endovascular stroke therapy outcomes

- Faster growth linked to poorer outcome among patients who did not achieve successful recanalization

Among patients who do not achieve successful recanalization with endovascular therapy for large vessel occlusion, greater diffusion-weighted imaging lesion growth rate (IGR) is associated with a lower chance of favorable outcome, researchers report.

For their study published in the September 2016 issue of Stroke, Jean-Marc Olivot, MD, PhD, of Toulouse University Hospital (Toulouse, France), and colleagues looked at 166 patients with acute brain infarction complicating an occlusion of the internal carotid or middle cerebral artery who were treated at Bichat University Hospital between April 2007 and March 2013. They calculated each patient’s IGR by dividing lesion volume on diffusion-weighted imaging by the delay from onset to MRI.

Median IGR was 7 mL/hour (interquartile range 2-26 mL/hour), and 68 patients (41%) experienced a favorable outcome, defined as an mRS score ≤ 2 at 90 days after onset of the occlusion.

Patients with successful recanalization, defined as a TICI score 2b/3 and achieved in 55% of cases, were more likely to have a favorable outcome than those without. The link successful recanalization and outcome grew with incresing IGR rate. But after adjustment for age, systolic blood pressure, vessel site occlusion, NIHSS score, and use of antithrombotic medication, only an IGR greater than 13.8 mL/hour was associated with a decreased occurrence of favorable outcome (table 1).

Table 1. Rate of Favorable Outcome

Each standard-deviation increase in IGR of 0.58 mL/hour was associated with a 40% lower odds of favorable outcome (adjusted OR 0.60; 95% CI 0.38-0.94).

However, the link between IGR and outcome was only present among patients who did not achieve successful recanalization (adjusted OR 0.32; 95% CI 0.12-0.85; P = .02).

A Sign of Size and Aggressiveness

“In our study, the median delay from onset to MRI was 105 minutes,” write the authors. “Our results confirm a high IGR variability at this early time point and after stratification on vessel occlusion site. We hypothesize that as previously demonstrated, hypoperfusion severity and collateral score contributed to this variation in addition to the site of occlusion.”

Unlike in previous studies, however, the assocation between IGR and outcome persisted even after controlling for NIHSS score. The authors hypothesize that “IGR is not only a biomarker of large infarction but also an assessment of the aggressiveness of the ongoing ischemic process.”

But the impact of IGR did not persist among patients who achieved successful recanalization, a group in which even those with the highest IGR benefited, the authors point out. This may suggest that successful recanalization occurring after a median delay of 4.5 hours, the time frame seen in the current study, “may dramatically alter the course of a fast progressing ischemic lesion outlined by DWI,” they say. “Also, we do hypothesize based on the results of previous studies that in addition to the prevention of the infarct progression, part of the beneficial effect may also be related to the reversal of the acute DWI lesion.”

The current findings may mean that the “patients who may benefit the more from an acute revascularization are the ones experiencing the more aggressive subtype of [brain infarction],” they write. “On the contrary, this rapid progression may lead to critical volumes associated with limited salvageable penumbra for which reperfusion may be futile or even deleterious.”

Source:

Olivot JM, Sissani L, Meseguer E, et al. Impact of initial diffusion-weighted imaging lesion growth rate on the success of endovascular reperfusion therapy. Stroke. 2016;47:2305-2310.

Disclosures:

Dr. Olivot reports receiving consulting fees from Astra Zeneca, Boston Scientific, and Servier and lecture fees from Bristol-Myers Squibb and Boehringer Ingelheim

fShare

Tweet