Hemodynamic effects of subclavian steal phenomenon on contralateral vertebral artery.
OBJECTIVE
Increased blood flow velocity in the contralateral vertebral artery (VA) is a common finding in subclavian steal syndrome, but its clinical relevance is not known. The aim of this study was to investigate whether the degree of velocity increase in the contralateral VA correlated with the severity of the steal.


METHODS
In a retrospective study of 62 patients with subclavian steal phenomenon and 62 sex- and age-matched controls, we analyzed the peak systolic velocity (PSV), end diastolic velocity (EDV), mean velocity (MV), resistance index (RI), and pulsatility index (PI) of the Doppler spectrum of the VA contralateral to the subclavian steal phenomenon. Clinical information including sex, age, comorbidities and Doppler data were recorded from the sonography registration form.


RESULTS
In patients with subclavian steal syndrome, Doppler spectral analysis showed a complete reversal of flow in the VA in 29 patients (group A) and an alternating flow in 33 patients (group B). The PSV, MV, RI, and PI of the contralateral VA of patients from both groups were higher than in controls (p < 0.01 for both comparisons). The PSV, EDV, and MV in the contralateral VA were higher in patients with reversed flow compared with those with alternating flow (p < 0.05). Comparisons of clinical symptoms and comorbidities between the two groups did not yield significant findings.


CONCLUSIONS
The degree of flow velocity increase in the contralateral VA artery correlates well with the severity of subclavian steal phenomenon.
First Department of Neurology, Chang Gung Memorial Hospital, 123 Ta-Pei Road, Niao-Sung Hsiang, Kaohsiung County 833, Taiwan.
Teng-Yeow
TY
Tan
Ulf
U
Schminke
Ting-Yao
TY
Chen
D000368:Aged; D001783:Blood Flow Velocity; D016022:Case-Control Studies; D016009:Chi-Square Distribution; D005260:Female; D006801:Humans; D008297:Male; D011673:Pulsatile Flow; D012189:Retrospective Studies; D013349:Subclavian Steal Syndrome / Q000000981:diagnostic imaging* / Q000503:physiopathology; D018608:Ultrasonography, Doppler; D014711:Vertebral Artery / Q000000981:diagnostic imaging* / Q000503:physiopathology