Vignan Yogendrakumar, MD, MSc

Tan Z, Parsons M, Bivard A, Sharma G, Mitchell P, Dowling R, Bush S, Xu A, Yan B. Optimal Tissue Reperfusion Estimation by Computed Tomography Perfusion Post-Thrombectomy in Acute Ischemic Stroke. Stroke. 2021.

In the thrombectomy era of acute stroke care, it is commonplace to utilize mTICI scores as one of the primary measures of assessing reperfusion status immediately post-procedure. In many studies, it is common to see a measure of mTICI scores 2b-3 as a representation of a good study outcome. However, registry data shows us that mTICI 2b scores are associated with an independent functional state in only 40% of patients. While the surrogate use of mTICI status to represent tissue reperfusion status is certainly a reasonable approach, the association between mTICI score and actual tissue status remains unclear.

In this study by Tan and colleagues, acute stroke patients treated at the Royal Melbourne Hospital with endovascular clot retrieval underwent CT or MRI perfusion at 24-36 hours post procedure. Comparing the baseline and follow-up perfusion scans, the authors defined optimal tissue reperfusion (TOR) as a >90% reduction of penumbra (using TMax>6s) volume. In 82 patients, those who had higher mTICI scores were more likely to achieve TOR at follow-up. Notably, achieving mTICI scores of 2c or 3 were more likely to be associated with TOR compared to mTICI 2b. Clinically, TOR was associated with improved clinical outcomes in multivariable logistic regression models.

While more investigations into post-procedure tissue reperfusion status are required, the findings of this study highlight two things: a) that higher mTICI scores are associated with better tissue perfusion status, but also b) there is notable difference in tissue perfusion between mTICI 2c/3 and 2b. Moving forward, in both routine care and clinical trials, we may need to aim towards mTICI 2c and 3 as our actual standard of success.

Disclosure: While he was not involved in the conduct of this study, Dr. Yogendrakumar is presently a fellow and PhD candidate at the Royal Melbourne Hospital.