Thrombectomy Less Beneficial in Large-Core Stroke

BASEL, Switzerland — Although thrombectomy has been shown to be beneficial in patients with large-core ischemic stroke, a new analysis suggests that patients with the greatest volume of tissue injury benefit less.

The randomized SELECT2 trial recently showed that patients with large-core ischemic stroke benefit from thrombectomy compared with medical management.

Now, a new secondary analysis of the data shows that in patients with a volume of severe hypodensity ≥ 26 mL within their ischemic lesions —– which indicates more evolved tissue injury — the benefit from thrombectomy is uncertain and the risk for hemicraniectomy is increased. 

“This is a proof of concept showing that the amount of tissue of injury does have an effect on the outcomes after endovascular therapy,” said investigator Vignan Yogendrakumar, MD, Royal Melbourne Hospital, Melbourne, Australia. 

“Further validation is required with independent data as the techniques used in this analysis are relatively novel. However, if validated, the prognostic value of assessing CT hypodensity could be used to assist with bedside decision-making, accelerate innovations in automated imaging processing, and could even be used as a biomarker for trial recruitment of new therapies designed to limit reperfusion injury,” he added. 

The findings were presented recently at the recent European Stroke Organization Conference (ESOC) 2024.

The analysis used imaging and outcome data from the 322 patients with large-core ischemic stroke included in the trial to look at whether the occurrence of severe hypodensity modified the effect of thrombectomy. 

The results showed that as the volume of severe hypodensity increased, the odds of a favorable outcome (Modified Rankin Scale [mRS] score 0-3; independent ambulation) with endovascular therapy decreased. 

At a cutoff of ≥ 26 mL for severe hypodensity, thrombectomy was no longer associated with a favorable outcome compared with medical management (Table 1). 

P for interaction =.003 

In addition, patients with higher volumes of severe hypodensity were more likely to undergo decompressive hemicraniectomy if they had undergone endovascular therapy (Table 2). Whereas in those with lower volumes of severe hypodensity, rates of decompressive hemicraniectomy were similar in the endovascular and medical treatment groups. 

P for interaction =.04 

A Promising Beginning

Commenting for Medscape Medical News, Pierre Fayad, MD, chief of the Vascular Neurology and Stroke Division, University of Nebraska Medical Center, Omaha, Nebraska, described the new analysis as a ” good and promising beginning.” 

Fayad n oted there have been concerns about recanalization with thrombectomy of large core infarctions because of the potential for bleeding and edema, but five published randomized controlled trials and one presented but unpublished trial have now shown that thrombectomy improved good outcomes without too many complications in such patients. 

A previous analysis from the SELECT2 trial also showed that in patients with large-core strokes treated with thrombectomy, clinical outcomes worsened as presenting ischemic injury estimates increased. 

“We now come to the second, more rational phase of teasing apart and understanding who among these patients benefit the most and who does not benefit,” Fayad said, adding that the tools for patient selection are limited and challenging. For example, the ASPECTS score on noncontrast CT has been the most commonly used but presents with a lot of variability. 

“This subgroup analysis of patients in SELECT2 measuring the volume of early ischemic severe CT hypodensity as a predictor of outcome shows value and promise. The results suggest the possibility of excluding patients who are least likely to benefit. However, it remains a secondary exploratory analysis and will need to be confirmed in further research,” Fayad concluded. 

Also commenting on the findings for Medscape Medical News, Joseph Broderick, MD, professor of neurology and director of the Neuroscience Institute at the University of Cincinnati, Ohio, noted that the new analysis is timely as “not all ASPECTS scores are created equal,” Broderick said. 

“These data, if validated, provide a more fine-tuned approach to the use of endovascular therapy in patients with larger volumes of ischemic core,” he added. 

Broderick explained that greater intensity of hypodensity has been recognized as a marker for a greater likelihood of unsalvageable brain. 

“There are some parallels with diffusion/flair mismatch that have been used to identify patients who may benefit from reperfusion. The next step will be to test these parameters in other published and reported large-core trials, but time to first image and time to treatment will be important variables to be considered in validating these data and incorporating them into clinical practice,” he added. 

The SELECT2 trial was supported by an investigator-initiated grant from Stryker Neurovascular to University Hospitals Cleveland Medical Center and the University of Texas McGovern Medical School. Yogendrakumar, Fayad, and Broderick report no relevant disclosures.