What You Should Know About Screening For PAD
Pearls On Conducting The Physical Exam
After assessing patients for possible claudication and completing the risk factor profile, does the clinical picture of the patient match your suspicions? The lower extremity vascular tree is the most important feature of the physical exam when it comes to the presence of PAD. Are the pedal pulses diminished or absent? Are the popliteal and femoral pulses palpable?
Keep in mind that you may see an array of physical findings. These findings may include many of the trophic changes within the physical exam. Cool temperatures are not always present due to collateralization. Muscle atrophy and weakness may or may not be present.
When one suspects moderate to significant PAD, the physician should evaluate the tone and presence or absence of the gastrocnemius muscle. This is a unique muscle of the lower extremity because only the sural nerves supply the muscle with no available collateral development.
The information one gathers from the claudication assessment, the risk factor profile and the physical exam should provide a clear picture for determining whether non-invasive vascular studies are necessary. Non-invasive vascular studies provide objective, quantitative information should you need to refer the patient for an appropriate vascular consult.
How Reliable Is The ABI In Gauging PAD Risk?
The ankle brachial index is the most sensitive and reproducible test when it comes to gauging the associated risk for the development of morbidity and mortality related to the development of PAD. The American Heart Association and the American College of Cardiology have recommended practice guidelines on how to obtain a proper ABI.10
First, the patient needs to be in a supine position for 10 minutes. Proceed to measure the systolic blood pressures of both brachial arteries and use the highest one in the calculation. Then obtain the systolic blood pressure of both the dorsalis pedis and posterior tibial arteries. Use the larger value for the calculation of the ABI for the respective limb.
In regard to these values, there is much debate as to when one should refer a patient to a vascular specialist in the case of moderate PAD. Podiatric physicians should refer these patients to an internal medicine doctor, if they do not already have one, to begin a regimen of appropriate exercise therapy and/or drug therapy.
There is no debate that any patient who demonstrates critical limb ischemia (CLI) should obtain an immediate referral to a vascular specialist. These patients are at a high risk of developing ischemic ulcerations, rest pain or gangrene — if they do not already exhibit some of those signs — and tend to trend downward without intervention.
Be aware that patients who have elevated ABIs > 1.30 have incompressible arteries that decrease the specificity of the test. For these patients, the arterial Doppler can be useful for evaluating increasing levels of ischemia. Dopplers are useful in the presence of significant calcification with non-compressible vessels. The peak velocity and morphology of the waveforms become more useful for interpreting the levelof disease.
Peripheral arterial disease is becoming more of a concern with an increasing number of people who are being diagnosed with diabetes. Many of these patients will be coming to see their podiatrist with or without ymptoms. Considering the prevalence of asymptomatic PAD, patients who are at risk need to undergo assessment.
Dr. Sefcik is a first-year resident at Pontiac Osteopathic Hospital in Pontiac, Mich.
Dr. Wilusz is a Fellow of the American College of Foot and Ankle Surgeons. He is in private practice in Clarkston, Mich.