Doppler-derived percentage systolic window and the quantitation of arterial stenosis

T. J. Psyhojos, T. G. Lynch, C. T. Araki, R. W. Hobson, H. E. Pawel

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1 Scopus citations


Peak systolic frequency (PSF) and percentage systolic window (%SW) are spectral parameters used to characterize poststenotic flow velocity patterns. The PSF, obtained using a continuous-wave (CW) Doppler velocimeter, has been used more frequently, however, in the quantitation of carotid occlusive disease. The authors have employed a microprocessor-driven pulsatile flow model to evaluate more completely the relationship between stenosis and the %SW. Using an 8MHz CW Doppler probe, the Doppler-shifted frequencies were recorded at 1, 2, 3, 4, and 5 diameters distal to a variable, nonaxisymmetric stenosis, which reduced the cross-sectional area (CSA) 25, 40, 50, 60, 70, 85, and 97 per cent. Four sets of observations were made and the %SW derived using a spectrum analyzer. At one diameter from the stenosis, the relationship between the %SW (Y) and the reduction in CSA (χ) is best described by two first-order regressions (Y = Mχ + B). The slope of the relationship from 0 to 60 per cent reduction in CSA is nearly flat, -0.052, while there is a significant (P < 0.05) decrease in the slope, -1.538, when the CSA is further reduced from 60 to 97 per cent. Beyond 1 diameter, the relationship is best described by a single linear regression, the gradual slope of which does not permit clinically useful comparisons. These data explain the lack of strong correlation between CSA and %SW when the data are evaluated over the entire range of stenoses. However, they do indicate that the %SW may be a useful correlate if it is obtained within one diameter of the stenosis.

Original languageEnglish (US)
Pages (from-to)646-650
Number of pages5
JournalAmerican Surgeon
Issue number12
StatePublished - 1986

ASJC Scopus subject areas

  • Surgery


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