Keys To Diagnosing And Addressing PAD In Patients With Wounds
With increasing numbers of elderly patients and patients with diabetes, clinicians will encounter more and more patients with wounds and ischemic legs. In the United States, an estimated 8 million patients, or approximately 12 percent of the adult population, have peripheral arterial disease (PAD).1 Accordingly, our expert panelists discuss pertinent diagnostic tips, appropriate referrals and how to ensure adequate follow-up on these high-risk patients who often present to wound care centers.
What characteristics in patients with wounds make you suspect PAD?
After implementing a strict, non-compromising pressure reduction plan (total contact cast or instant total contact cast), Nicholas Bevilacqua, DPM, notes a well perfused, uninfected wound should reduce in size by 50 percent after four weeks.
When patients present with a non-healing wound, he says one must rule out underlying infection, ischemia and ensure an appropriate offloading plan. However, if the wound is properly offloaded and there are no clinical signs and symptoms of infection, Dr. Bevilacqua says physicians must suspect PAD. He says ischemic ulcers often appear on the distal aspect of the toes. The wound base with these ulcers is often fibrotic and may contain necrotic tissue, according to Dr. Bevilacqua.
To Kazu Suzuki, DPM, CWS, it is “quite obvious” that if patients have dry, gangrenous toe wounds, they most likely have severe PAD. On the other hand, when it comes to ischemic legs, he notes the most typical physical exam findings — such as lack of hair growth, shiny and atrophic skin, or pulses that are difficult to palpate — are not accurate enough to rule in or rule out PAD.2 Therefore, Dr. Suzuki recommends a subsequent Doppler exam to help evaluate leg perfusion right after the physical exam and prior to wound debridement procedures.
Desmond Bell, DPM, concurs, noting that a cursory Doppler exam can provide “extremely valuable” information in comparison to palpation of pedal pulses. He advocates regular non-invasive arterial screening for all patients with diabetes. Dr. Bell notes that any diabetic foot ulcer may have a component of arterial insufficiency as a contributing factor in addition to the structural deformities and reduced ability to heal that are inherent in patients with diabetes.
Furthermore, Dr. Bell says ulcers previously diagnosed as being due to chronic venous insufficiency often have an arterial component, which physicians can easily overlook if they do not perform a thorough arterial assessment.
“Just because it looks like a venous ulcer does not mean it is fully venous in etiology,” cautions Dr. Bell.
One should also suspect PAD or critical limb ischemia when toe ulcers are accompanied by intense pain and other changes such as dependent rubor or cyanosis, according to Dr. Bell.
Based on the American College of Cardiology/American Heart Association (ACC/ AHA) guidelines for the management of PAD, Dr. Suzuki assumes most of his patients over 70 years of age have some degree of PAD.3 He also assumes the presence of PAD in those over 50 years of age with known risk factors of diabetes; a history of smoking, hypertension and high cholesterol; or other cardiovascular diseases, coronary artery disease or stroke.
For example, in the case of a 60-year-old male patient with palpable pulses, Dr. Suzuki would consider him at high risk for PAD if he has diabetes with a history of heart attack and coronary artery bypass graft (CABG). He says such a patient would probably have some degree of stenosis and plaques in his leg arteries in the same manner that he had stenosis in his coronary arteries.
Dr. Suzuki also cautions that the probability of PAD increases as we age and 20 percent of 70-year-old Americans are known to have PAD.1 Given that he frequently sees new wound patients in their 80s and 90s, Dr. Suzuki would presume they would have some degree of PAD.