Jay Shah, MD

Nogueira RG, Haussen DC, Dehkharghani S, Rebello LC, Lima A, Bowen M, et al. Large Volumes of Critically Hypoperfused Penumbral Tissue Do Not Preclude Good Outcomes After Complete Endovascular Reperfusion: Redefining Malignant Profile. Stroke. 2016

Reperfusion in acute ischemic stroke is a fine balance between improved clinical outcomes and potential reperfusion injury. Therefore, judicious patient selection is essential. Pooled analysis from both DEFUSE and EPITHET studies confirmed poor outcomes in patients achieving reperfusion with malignant profile. This profile was defined with perfusion volumes of 85 cc and greater. The DEFUSE trial also defined a target mismatch profile that could distinguish ideal candidates for reperfusion therapy. However, this was derived from perfusion imaging that used a Tmax > 10 second threshold. This threshold was established in the pre-stent retriever era which is known to result in faster and better reperfusion. In this study, the authors evaluated the impact of the malignant profile using Tmax > 10s lesion on outcomes of patients undergoing complete reperfusion with stent retrievers.

This was a retrospective review from a database of patients with anterior circulation large-vessel occlusion that underwent CT perfusion imaging and achieved full reperfusion. Follow-up MRI were obtained to determine final infarct volume. The primary outcome was impact of Tmax >10s lesion on infarct growth. In total, 113 patients were included. Patients with malignant profile lesions had larger baseline and core infarct volumes. However, there were no significant differences in absolute volume of infarct growth, 90-day mortality or severe intracranial hemorrhage.

This study suggests that large volumes of severely hypoperfused tissue on CT perfusion are not associated with higher rates of infarct growth, severe hemorrhage, or unfavorable outcomes as long as there is not a large baseline ischemic core. The implications of this study is important in that patients who may potentially benefit from reperfusion therapy should not be excluded. Since reperfusion therapy has been proven to demonstrate clinical efficacy, the focus has appropriately been on ideal patient selection. This study is limited by its relatively small size, retrospective nature, and small percentage of patients receiving intravenous thrombolytics. This latter limitation may confound the findings in that thrombolytic remains the first line therapy as long as no absolute contraindications are present. Future prospective trials are needed to determine ideal endovascular candidates.