To evaluate the incidence of ultrasound vasospasm in Posterior Reversible Encephalopathy Syndrome (PRES) and Reversible Cerebral Vasoconstriction Syndrome (RCVS), its association with acute cerebral ischemic injury and the long-term functional status.

PRES and RCVS can induce cerebral vasospasm e ischemia. Transcranial Doppler is an established test for monitoring these complications in other clinical settings, but its role in these syndromes has not been determined.

Multicentric retrospect study of adults diagnosed with PRES or RCVS, between 2008 and 2020, who underwent transcranial color Doppler (TCCD) and cerebral magnetic resonance imaging (MRI). Vasospasm was determined accordingly to the reference criteria for subarachnoid hemorrhage.  Acute cerebral ischemia was ascertained via MRI with diffusion weighting imaging (DWI+). Functional outcome was based on the modified Rankin scale (mRS) at 90 days. The association between vasospasm and the functional prognosis was studied by multivariate logistic regression.

We included 71 cases (45 PRES and 26 RCVS), 67% females, mean age of 46 years (SD=16). Twenty-three patients fulfilled criteria for ultrasound vasospasm (32%), of which 87% were women. We recorded 14 (20%) DWI+ cases. In PRES, vasospasm was significantly associated with the presence of DWI+ lesions [30 vs 19%, adjusted odds ratio (aOR)=7.7, confidence interval (CI) 95% 1.3-86.0, p=0.03].  In RCVS, we didn’t find a significant association between vasospasm and DWI+ lesions. The presence of DWI+ lesions was independently associated with reduced likelihood of good functional prognosis (36 vs 74%, aOR=0.20, 95% CI 0.05-0.80, p=0.02).

Ultrasound vasospasm is detectable in a third of the patients with PRES/RCVS and is associated with DWI+ ischemic lesions only in PRES. TCCD monitoring can help to stratify patients at risk of cerebral ischemia, a strong predictor of long-term functional prognosis.