Assessing Vascular Surgery Options In Patients With PAD
Pertinent Diagnostic Pointers
When it comes to the diagnosis of PAD, there are a number of components, beginning with an in-depth history and physical examination. It has been noted that practitioners often miss the diagnosis of PAD during a routine physical exam. Ninety-two percent of the time, physicians perform cardiovascular histories during exams but only 37 percent of internists address questions and history regarding PAD.8 During the history portion of the exam, it is important to ask if the patient has any other medical problems or conditions, such as Leriche syndrome, which can have some of the same signs and symptoms of PAD.
Internists also only calculate an ABI or palpate a dorsalis pedis pulse 60 percent of the time in comparison to the heart and lung exam, which patients undergo 92 percent of the time. During the history and physical, one should emphasize the peripheral vasculature, take blood pressure, palpate pulses (taking into account the quality of the pulse), and perform auscultation of pulses and bruits in addition to noninvasive and, if necessary, invasive diagnostic testing.8 Noninvasive testing includes ABI, segmental pulse pressures, exercise testing and ultrasonic duplex scanning.
Ankle-brachial indices have become a mainstay in the initial evaluation of patients suspected to have PAD. They are simple to perform as they only require the use of an ordinary blood pressure cuff and a Doppler ultrasound. A reduced ABI in patients with claudication symptoms confirms the presence of an occlusive disease between the heart and the ankle. An ABI reading of <0.90 is the cutoff point for the diagnosis of PAD.3 The lower the ABI, the more severe the occlusive disease.
Measurement of segmental pressures and pulse volume recordings can localize occlusions of different limb segments. One would compare systolic blood pressures and pulse volumes to segments both distal and proximal to the occlusion.
If the area of the occlusion needs to be localized further than the arterial segments, a duplex ultrasound is a good diagnostic measure.4 One can use a duplex ultrasound to obtain information on artery wall thickness, the degree of flow turbulence, changes in blood flow velocity in areas of stenosis and vessel morphologic characteristics.8 Since the duplex ultrasound is costly in comparison to other noninvasive tests, physicians should reserve it for patients who need more detailed information on flow characteristics and vessel morphology. An arteriogram is a roadmap for treatment only and cannot qualify the quantity of flow.9