Page 153 - Libro 2

8 — Indirect Assessment of Arterial Disease
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Figure 8-10 Normal PVR waveforms from the right lower extremity, whereas the left lower extremity results indicate stenosis (or occlusion with collateralization) in the iliofemoral segment, with the suggestion of additional disease at femoropopliteal level and severe disease below the knee. (Image courtesy of John Hobby, RVT, Pueblo, CO.)
noncompressible and can be substituted for ABIs when assessing the response to exercise. Toe pres- sures may also be expressed directly in millimeters of mercury. To indicate the likelihood of healing fol- lowing a vascular procedure in the forefoot/toe seg- ment, 50 mm Hg is regarded as adequate even in the presence of diabetes.
Upper extremity digital pressures are important in the workup prior to the creation/revision of dialysis
fistulas and grafts, and for assessing steal from the hand by the fistula/graft. The absolute pressure indi- cates present or potential ischemia of the hand or it can be used to calculate a digit–brachial index (DBI), similar to ABIs and TBIs. The normal value for the DBI is 􏰃0.9 (Table 8-4d).17 In dialysis patients who are symptomatic for fistula steal, the digital pressures should double when the outflow side of the fistula is compressed.