Editors' Note: Prevalence and Significance of Impaired Microvascular Tissue Reperfusion Despite Macrovascular Angiographic Reperfusion (No-Reflow).

Abstract

Pooling data from the EXTEND-IA, EXTEND-IA TNK, and EXTEND IA-TNK part 2 clinical trials, Dr. Ng et al. found that persistent hypoperfusion (“no-reflow”) on follow-up perfusion imaging after successful recanalization was common and associated with poor clinical outcomes. One in 4 patients had perfusion imaging evidence of “no-reflow” at 24 hours, and this radiographic finding accounted for 60% of the final infarct volume and was associated with a 4-fold higher odds of being functionally dependent or dead by day 90. Dr. Schiphorst et al. sought to validate these findings using their data set but found the prevalence of “no-reflow” occurred in half as many patients. They also emphasize that the relationship of no-reflow and clinical outcome is uncertain. Nonetheless, inherent methodologic differences in these studies, specifically selection bias for 24-hour perfusion imaging may account for the variability in findings. The systematic use of perfusion imaging in 99% of included patients from the pooled analysis by Ng et al. and larger sample size make for a convincing argument that postreperfusion hypoperfusion is not only common, but a useful prognostic factor. Pooling data from the EXTEND-IA, EXTEND-IA TNK, and EXTEND IA-TNK part 2 clinical trials, Dr. Ng et al. found that persistent hypoperfusion (“no-reflow”) on follow-up perfusion imaging after successful recanalization was common and associated with poor clinical outcomes. One in 4 patients had perfusion imaging evidence of “no-reflow” at 24 hours, and this radiographic finding accounted for 60% of the final infarct volume and was associated with a 4-fold higher odds of being functionally dependent or dead by day 90. Dr. Schiphorst et al. sought to validate these findings using their data set but found the prevalence of “no-reflow” occurred in half as many patients. They also emphasize that the relationship of no-reflow and clinical outcome is uncertain. Nonetheless, inherent methodologic differences in these studies, specifically selection bias for 24-hour perfusion imaging may account for the variability in findings. The systematic use of perfusion imaging in 99% of included patients from the pooled analysis by Ng et al. and larger sample size make for a convincing argument that postreperfusion hypoperfusion is not only common, but a useful prognostic factor.