Atherosclerosis is the major cause of poor arterial flow in the foot. It decreases flow by narrowing or occluding the arterial lumen. In patients with diabetes, you’ll see occlusion in the distal bifurcation points. However, in non-diabetic patients, you’ll most often see the occlusion at proximal points.1 It is important that we are able to recognize the presence and severity of disease. Symptoms of claudication and ischemic rest pain are important warning signs that suggest the need to order NIV studies.
In addition to ordering NIVs for those with atherosclerosis, you should also order NIV studies for patients who have:
• signs of critical ischemia, skin changes or gangrene;
• absent or diminished pedal pulses; or
• femoral bruits.
Then there’s the question of which NIV study is best for the given clinical situation. Here are some key points to keep in mind.
• The ABI/TBI/PPG have been shown to be closely associated with arterial physiology for vascular evaluation of the distal foot.
• Segmental pressure measurements and exercise testing can give you reliable information on iliac and femoral popliteal occlusive disease.
• Employing TCOM helps to determine the severity of lower extremity arterial occlusive disease and ascertain the greatest likelihood of healing ulcers or success in digital amputations.
• Dopplers are an excellent adjunctive modality in finding the exact location of stenosis/occlusion and when ABI and segmental pressures are inconclusive.
It’s also essential to pay close attention to the testing environment. Be aware of things like ambient temperature, the patient’s state of relaxation and limb positioning.
Understanding the limitations of these NIV studies is necessary for applying the results to clinical situations.