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OBJECTIVES:
Segmental pressures and air plethysmography waveform (APW) analysis are widely used for noninvasive diagnosis of lower extremity peripheral arterial disease (PAD). Pressure criteria for identifying significant PAD above the level of the common femoral artery (INFLOW) have been extensively reported. In contrast, the contribution of APW analysis to the interpretation of INFLOW is negligible and subjective. The purpose of this study is to examine the characteristics of the thigh arterial pulse waveform to determine which features best identify INFLOW disease (>/=50% diameter).
METHODS:
Non-diabetic vascular laboratory patients having segmental APW analysis and arteriography within thirty days of the noninvasive procedure were investigated. Thigh air plethysmography waveforms were evaluated for: 1) acceleration time (TIME) from onset to peak systole; 2) relative amplitude reduction (RAR) one-fifth of a second after peak systole; and 3) waveform down-slope curvature (CURV) in relationship to baseline.
RESULTS:
46 extremities were analyzed. Normal arteries or insignificant INFLOW was defined by thigh air plethysmography waveforms with >0.28< sec TIME and inward CURV, or <0.28 sec TIME and even CURV. Borderline INFLOW was defined 0.28 sec TIME, RAR >0.50< and inward or even CURV. Significant INFLOW was defined >0.28 sec TIME and outward or even CURV. Sensitivity for defining INFLOW was 94% (15/16) and specificity 81% (26/30); positive predictive value was 79% (15/19) and negative predictive value 96% (26/27).
CONCLUSIONS:
Thigh-level APW characteristics may improve identification of INFLOW disease in non-diabetic patients undergoing physiologic testing for lower extremity PAD.