Objective: Reversible cerebral vasoconstriction syndromes (RCVS) are characterized by thunderclap headaches and reversible cerebral vasoconstrictions. No systematic studies on cerebral hemodynamics have been published.
Methods: Patients with RCVS were consecutively recruited. Sequential transcranial color-coded sonography studies were performed on the middle cerebral artery (MCA) for 3 months. Mean flow velocities (V(MCA)) and Lindegaard Index (LI) were recorded and compared with those of controls.
Results: Thirty-two patients (all female; average age, 49.7 +/- 6.8 years) were enrolled. Four developed of reversible posterior leukoencephalopathy syndrome, and two of them, ischemic strokes. One hundred and twenty-six sonography studies were performed on 57 eligible MCAs. The mean maximum V(MCA) (109.5 +/- 30.8 cm/sec) and LI (2.2 +/- 0.7) of RCVS patients exceeded those of controls (V(MCA): 66.3 +/- 9.5 cm/sec, p < 0.001; LI: 1.4 +/- 0.3, p < 0.001). The V(MCA) and LI levels were still at their plateau at the mean time (day 22 after headache onset) of headache resolution. Fifteen (46.9%) patients had V(MCA) exceeding 120 cm/sec, and 5 (16%) had LI exceeding 3. Patients fulfilling the criteria of subarachnoid hemorrhage mild vasospasm (n = 4; 13%), that is, both V(MCA) greater than 120 cm/sec and LI greater than 3, had a greater risk of posterior leukoencephalopathy (75 vs 4%; p = 0.003) and ischemic strokes (50 vs 0%; p = 0.01) than those without.
Interpretation: Patients with RCVS experienced prolonged vasoconstriction, making the risk for posterior leukoencephalopathy and ischemic strokes outlast headache resolution. Patients fulfilling mild vasospasm criteria for subarachnoid hemorrhage carry a high risk.