Chapter 7-9: Peripheral Arterial Disease (PAD)

TEXTBOOK PRESENTATION

Classic claudication is defined as reproducible, exercise-induced calf pain that requires stopping and is relieved with < 10 minutes of rest. Critical limb ischemia classically presents with pain in the feet at rest that may be relieved by placing the feet in a dependent position.

DISEASE HIGHLIGHTS

1. In a study of outpatients over the age of 70, or aged 50–69 with a history of smoking or diabetes, the prevalence of PAD was 29%.

   1. Only 11% of the patients with PAD had classic claudication.

   2. 47% of patients had atypical symptoms (exertional leg pain that was not in the calf or was not relieved by rest), and 42% had no leg pain.

2. Critical limb ischemia is the presenting manifestation in 1–2% of patients.

3. Risk factors include

   1. Smoking and diabetes are the strongest risk factors (relative risk of PAD increases by 1.4 for every 10 cigarettes smoked/day and by 2.6 in patients with diabetes).

   2. Hypertension and hyperlipidemia are also risk factors.

   3. Patients with other vascular disease have a high prevalence of PAD (19% in patients with ischemic heart disease and 26% in patients with stroke).

   4. The prevalence of asymptomatic patients with risk factors ranges from 7% to 15%.

4. Patients with PAD have a high prevalence of coronary artery disease and cerebrovascular disease with an annual rate of cardiovascular events of 5–7%.

5. PAD is associated with a progressive decline in walking endurance and an increased rate of depression.

EVIDENCE-BASED DIAGNOSIS

1. History

   1. The presence of classic claudication has an LR+ = 3.30.

   2. The absence of classic claudication has an LR− = 0.89.

2. Physical exam

   1. Skin changes

      1. In symptomatic patients, skin being cooler to the touch and the presence of a foot ulcer in the affected leg both have an LR+ = 5.9 and an LR− of about 0.92.

      2. Skin changes (atrophic or cool skin, blue/purple skin, absence of lower limb hair) are not useful in assessing for PAD in asymptomatic patients.

   2. Bruits

      1. In symptomatic patients the presence of an iliac, femoral, or popliteal bruit has an LR+ = 5.6; the absence of a bruit in all 3 locations has an LR− = 0.39.

      2. In asymptomatic patients, the finding of a femoral bruit has an LR+ = 4.8; the absence of a femoral bruit does not change the probability of PAD.

   3. Pulses

      1. An abnormal femoral pulse has an LR+ = 7.2; an abnormal posterior tibial pulse has an LR+ = 8.10.

      2. An abnormal dorsalis pedis pulse does not substantially increase the probability of PAD (LR+ = 1.9); the dorsalis pedis pulse is not palpable in 8.1% of normal individuals.

      3. The absence of an abnormality in any pulse has a wide range of negative LRs (0.38–0.87).

   4. Capillary refill time

      1. Apply firm pressure to the plantar aspect of the great toe for 5 seconds; after releasing the toe, normal color should return in ≤ 5 seconds.

      2. Neither sensitive nor specific for diagnosing ...