Correlation of abnormal intracranial vessel velocity, measured by transcranial Doppler ultrasonography, with abnormal conjunctival vessel velocity, measured by computer-assisted intravital microscopy, in sickle cell disease

The Stroke Prevention Trial has confirmed that utilization of transcranial Doppler ultrasonography (TCD), which examines blood flow in large intracran ial vessels, can identify children with sickle cell disease (SCD) who are a t high risk of developing a premature stroke. It is not known to what exten t the vasculopathy in SCD involves small vessels and whether the abnormalit ies, if present, correlate with large-vessel vasculopathy. Eighteen childre n with SCD were examined with TCD to determine middle cerebral artery (MCA) velocity and computer-assisted intravital microscopy (CAIM) to determine b ulbar conjunctival vessel velocity during the same visit for vasculopathy c orrelation, High MCA velocity (greater than or equal to 200 cm/sec) was fou nd by TCD in 4 patients who also showed abnormal conjunctival velocity (< 0 .2 mm/sec or intermittent trickle flow) by CAIM, Three patients had conditi onal (greater than or equal to 170 cm/sec and < 200 cm/sec) MCA velocity: 2 showed abnormal (trickle) and 1 showed normal conjunctival velocity (1.9 m m/sec), One patient with unmeasurable MCA velocity had abnormal (trickle) c onjunctival velocity. Of the remaining 10 patients who had normal MCA veloc ity, 2 showed abnormal (0.05 mm/sec and 0.1 mm/sec) and 8 showed normal con junctival velocities (1.1-2.4 mm/sec), The MCA velocities correlated signif icantly with bulbar conjunctival flow velocities (P <less than or equal to> .008, Fisher exact test). A correlation exists between MCA(large-vessel) a nd conjunctival (small-vessel) flow velocities. CAIM is a noninvasive quant itative technique that might contribute to the identification of SCD patien ts at high risk of stroke. Small-vessel vasculopathy might be an important pathological indicator and should be further explored in a large-scale stud y. (Blood. 2001;97:3401-3404) (C) 2001 by The American Society of Hematolog y.