Background Increased middle cerebral artery (MCA) blood flow velocities on transcranial duplex sonography (TCD) were recently reported in individual patients after successful mechanical thrombectomy (MT) and were related to intracranial hemorrhage and poor outcome. However, the retrospective study design of prior studies precluded elucidation of the underlying pathomechanisms, and the relationship between TCD and brain parenchymal perfusion still remains to be determined.
Methods We prospectively investigated consecutive patients with stroke successfully recanalized by MT with TCD and MRI including contrast-enhanced perfusion sequences within 48 hours post-intervention. Increased MCA flow on TCD was defined as >30% mean blood flow velocity in the treated MCA compared with the contralateral MCA. MRI blood flow maps served to assess hyperperfusion rated by neuroradiologists blinded to TCD.
Results A total of 226 patients recanalized by MT underwent post-interventional TCD and 92 patients additionally had perfusion MRI. 85 patients (38%) had increased post-interventional MCA flow on TCD. Of these, 10 patients (12%) had an underlying focal stenosis. Increased TCD blood flow in the recanalized MCA was associated with larger infarct size, vasogenic edema, intracranial hemorrhage and poor 90-day outcome (all p≤0.005). In the subgroup for which both TCD and perfusion MRI were available, 29 patients (31%) had increased ipsilateral MCA flow velocities on TCD. Of these, 25 patients also showed parenchymal hyperperfusion on MRI (sensitivity 85%; specificity 62%). Hyperperfusion severity on MRI correlated with MCA flow velocities on TCD (rs=0.379, p<0.001).
Conclusions TCD is a reliable bedside tool to identify post-reperfusion hyperperfusion, correlates well with perfusion MRI, and indicates risk of reperfusion injury after MT.
- Blood Flow
Data availability statement
Data are available upon reasonable request. Study data are available from the corresponding author on reasonable request.
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Contributors MK: study design, acquisition and interpretation of data, manuscript preparation. NH: acquisition of data. OL: acquisition of data. HD: acquisition of data, critical revision of the manuscript content. SH: critical revision of the manuscript content. BP: acquisition of data. SF-H: acquisition of data, critical revision of the manuscript content. IH: acquisition of data. MH: acquisition of data. DP: acquisition of data. AP: acquisition of data. CE: study design, critical revision of the manuscript content. KW: critical revision of the manuscript content. MiK: critical revision of the manuscript content. TG: study design, acquisition and interpretation of data, manuscript preparation, critical revision of the manuscript. All authors have read and approved the final manuscript and agreed to be accountable for all aspects of the work. MK is responsible for the overall content as guarantor.
Funding This study was funded by Austrian Science Fund (FWF).
Competing interests None declared.
Provenance and peer review Not commissioned; externally peer reviewed.
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