A Guide to Diagnosing Peripheral Arterial Disease

Executive Summary

  • In PAD, the level of the lesion is grouped into three categories: aortoiliac, femoropopliteal, and tibiopedal/crural.
  • An ABI less than 0.90 is diagnostic for PAD in patients with claudication or other signs of ischemia, with 95% sensitivity and 100% specificity.
  • A proximal-to-distal decrease in sequential pressures greater than 20 mm Hg or a decrease in segmental-brachial index greater than 0.15 indicates occlusive disease and correlates with the level of the lesion.
  • A normal lower extremity arterial Doppler velocity tracing is triphasic, with a sharp upstroke and peaked systolic component, an early diastolic component with reversal of flow, and a late diastolic component with forward flow. A biphasic signal is considered abnormal if there is a clear transition from triphasic signal along the vascular tree. Monophasic waveforms are always considered abnormal.
  • Abnormal PVR findings include decreased amplitude, a flat peak, and an absent dicrotic notch.
  • In symptomatic patients with normal or borderline ABI at rest, an exercise ABI should be performed. The sensitivity for the detection of PAD may be increased with postexercise measurements.
  • Source Paper
  • Handy Reference (Angiologist)

rg-2017160044-fig1

In PAD, the level of the lesion is grouped into three categories: aortoiliac, femoropopliteal, and crural (tibiopedal)

Recent Use Trends

Review of Medicare Part B databases between 2002 and 2013 by Patel et al (10) revealed that MR and CT angiography nearly replaced diagnostic catheter angiography (DCA) in the diagnosis of PAD among radiologists, whereas the use of DCA rose sharply among cardiologists and surgeons despite available noninvasive alternatives.  (I will not editorialize since this follows every other major trend in utilization.)

Waveform

rg-2017160044-fig2

A normal lower extremity arterial Doppler velocity tracing is triphasic, with a sharp upstroke and peaked systolic component, an early diastolic component with reversal of flow, and a late diastolic component with forward flow. A biphasic signal is considered abnormal if there is a clear transition from triphasic signal along the vascular tree. Monophasic waveforms are always considered abnormal.

Exercise Study

In symptomatic patients with normal or borderline ABI at rest, an exercise ABI should be performed. The sensitivity for the detection of PAD may be increased with postexercise measurements. The patient should walk on a treadmill at 2 mph (3.22 km/h) at a 10%–12% grade for 5 minutes or until claudication symptoms develop. ABIs should be measured immediately after exercise and every minute until ABIs normalize to pre-exercise values. The examination allows assessment of functional limitation and should be reproducible to allow monitoring of response to therapy. A decrease in the ABI after exercise of greater than 0.2 indicates PAD. The time required for the ABI to return to baseline is also useful in detecting PAD. Ankle pressures normally return to baseline within 2 minutes after cessation of exercise. Return to baseline after 2–6 minutes of rest indicates single-segment disease (Fig 8), whereas return to baseline in 6–12 minutes indicates multisegment disease and return to baseline in greater than 15 minutes typically indicates rest pain (13). In addition, an exercise study may be useful to determine quantitative limitation in functional capacity secondary to claudication, which can then be used to assess response to therapy or an exercise program (29).

Advertisements

Leave a Reply

Please log in using one of these methods to post your comment:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s