Transcranial Doppler Hemodynamic parameters and risk of stroke - The Rotterdam study

Background and Purpose - We explored the association between transcranial Doppler hemodynamic parameters and the risk of stroke in the general population. Methods - At baseline, we assessed mean flow velocity, peak systolic flow velocity, end diastolic flow velocity, and vasomotor reactivity with transcranial Doppler in 2022 Rotterdam Study participants aged 61 years and over in both middle cerebral arteries. All participants, who at baseline were free from previous stroke, were subsequently followed for occurrence of stroke (average follow-up time 5.1 years). We calculated hazard ratios for the association between hemodynamic parameters and risk of stroke using Cox proportional hazards models with adjustment for age, sex, systolic blood pressure, antihypertensive drug use, diabetes mellitus, ever smoking, current smoking, carotid intima media thickness, and carotid distensibility. Results - Risk of stroke (n = 122) and ischemic stroke (n = 89) increased with increasing middle cerebral artery flow velocity; when comparing the tertile with highest velocity to the tertile with lowest velocity, the hazard ratio was 1.74 (95% CI: 1.09 to 2.77) for the association between mean flow velocity and stroke, 1.63 (95% CI: 1.03 to 2.58) for end diastolic flow velocity and stroke, and 1.33 (95% CI: 0.86 to 2.08) for peak systolic flow velocity and stroke. These estimates increased 10% to 26% when only ischemic strokes were included. The side of highest flow velocity was not associated with the side of stroke. We found no associations between vasomotor reactivity and risk of stroke. Conclusions - Risk of stroke increased strongly with increasing middle cerebral artery flow velocity as measured with transcranial Doppler in the general population.