Physical Examination and Chronic Lower-Extremity Ischemia a Critical Review
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ORIGINAL INVESTIGATION Physical Examination and Chronic Lower-Extremity Ischemia A Critical Review Steven R. McGee, MD; Edward J. Boyko, MD, MPH Objective: To determine the clinical utility of physical cians diagnose the presence of peripheral arterial dis- examination in patients with suspected chronic ische- ease: abnormal pedal pulses, a unilaterally cool extrem- mia of the lower extremities. ity, a prolonged venous filling time, and a femoral bruit. Other physical signs help determine the extent and dis- Data Sources: MEDLINE search (January 1966 to tribution of vascular disease, including an abnormal fem- January 1997), personal files, and bibliographies of oral pulse, lower-extremity bruits, warm knees, and the textbooks on physical diagnosis, surgery, and vascular Buerger test. The capillary refill test and the findings of surgery. foot discoloration, atrophic skin, and hairless extremi- ties are unhelpful in diagnostic decisions. Mathematical Study Selection: Both authors independently graded formulas, derived from 2 studies using multivariate analy- the studies as level 1, 2, or 3, according to predeter- sis, allow clinicians to estimate the probability of periph- mined criteria. Criteria deemed essential for analysis of eral arterial disease in their patients. sensitivity, specificity, and likelihood ratios were (1) clear definition of study population, (2) clear definition of Conclusion: Certain aspects of the physical examination physical examination maneuver, and (3) use of an ac- help clinicians make accurate judgments about the pres- ceptable criterion standard test for comparison. ence of peripheral arterial disease and its distribution. Results: The following positive findings help clini- Arch Intern Med. 1998;158:1357-1364 N HIS book The Circulatory Dis- helpful, especially capillary refill and de- turbances of the Extremities, pub- pendent rubor.2,3 lished in 1924, Buerger intro- Chronic arterial disease usually af- duced to clinicians several new fects 3 distinct segments in the lower limbs: physical signs of peripheral vas- the aortoiliac segment (especially the in- Icular disease. Whereas earlier writers on frarenal abdominal aorta and common iliac vascular disease had confined them- arteries), the femoropopliteal segment (es- selves to descriptions of gangrene, Buerger pecially the superficial femoral artery in stressed the importance of certain “pro- the adductor canal, a tunnel amid muscle dromal” findings, including absent pulses, groups of the middle third of the thigh), toe and foot ulcers, impaired nail growth, and the peroneotibial segment (below the soft tissue atrophy, poor capillary refill (the knee). Most patients have femoropop- “expression test”), foot pallor with eleva- liteal disease, aortoiliac disease, or both.4 tion, and a deep-red color of the limb in Significant peroneotibial disease is un- the lowered position (“erythromelia”).1 common unless the patient has diabetes Modern clinicians have accepted Buer- or thromboangiitis obliterans. According ger’s findings as characteristic of chronic to traditional teachings, disease in each of arteriosclerosis, a somewhat surprising in- these segments causes specific claudi- ference because Buerger considered them cation symptoms and pulse abnormali- most characteristic of thromboangiitis ties, and requires different surgical ap- obliterans, a rare form of small-vessel vas- proaches (Table 1). From the Department of culitis now known as Buerger disease. The ankle-to-arm systolic pressure in- Medicine, Veterans Affairs Moreover, other prominent physicians, dex (AAI), the most common criterion Puget Sound Health Care writing soon after the appearance of Buer- standard used in studies of physical diag- System, University of ger’s book, argued that some of Buerger’s nosis, is obtained by measuring the high- Washington, Seattle. findings were unreliable and clinically un- est systolic blood pressure at the ankle ARCH INTERN MED/ VOL 158, JUNE 22, 1998 1357 ©1998 American Medical Association. All rights reserved. Downloaded From: https://jamanetwork.com/ on 09/30/2021 0.97 identify patients with angiographically proven oc- clusions or significant stenoses with a sensitivity of 96% MATERIALS AND METHODS to 97% and specificity of 94% to 100%.6,8 Most patients with claudication have AAIs between 0.5 and 0.8 and dis- One of us (S.R.M.) performed a MEDLINE search of ease in a single segment; those with rest pain and gan- grene have AAIs less than 0.5 and disease in at least 2 articles published between January 1966 and Janu- 6-8 ary 1997 to retrieve all relevant publications on the segments. bedside diagnosis of peripheral vascular disease (the This review addresses the diagnostic accuracy of specific strategy was arterial occlusive diseases/di AND many of Buerger’s prodromal findings, compared with physical examination OR peripheral vascular dis- the AAI and other criterion standard measures, and ease/di OR intermittent claudication/di OR pulse/), whether certain aspects of the physical examination ac- all limited to the English language and human sub- tually help clinicians accurately determine the location jects. Based on review of titles and abstracts, rel- of the patient’s arterial occlusions and stenoses, as sug- evant publications were retrieved, including all ar- gested in Table 1. ticles that determined interobserver variability and all that compared physical signs with an objective cri- terion standard. To complete the search, the bibli- RESULTS ographies of these articles and those of textbooks on physical diagnosis, surgery, and vascular surgery were reviewed. DIAGNOSIS OF PERIPHERAL ARTERIAL DISEASE Both of us independently examined the se- lected studies for the following criteria: (1) clear defi- Examination of the Pedal Pulses nition of the study population, (2) clear definition of the physical examination maneuver, (3) use of an To best understand the diagnostic value of the pulse ex- acceptable criterion standard test (calculation of AAI, direct pressure measurement, angiography), (4) un- amination, it is important to first address interobserver biased selection of patients (ie, consecutive patients variation and the normal variations in the vascular per- or population-based sample), (5) predefined abnor- fusion of the foot. When deciding whether a particular mal thresholds for the criterion standard, and (6) pulse is present or absent, clinicians demonstrate fair to blinded comparison of test and criterion standard re- almost perfect agreement (k=0.20-0.92) (Table 2), al- sults. Studies satisfying all 6 criteria were graded level though attempts to distinguish the normal and reduced 1; those with fewer than all 6 but satisfying at least pulse cause considerable dissension (k=0.01-0.15) (Table 1, 2, and 3 were graded level 2; and all others were 2). Table 3 reveals that, in studies of large numbers of graded level 3. We discussed and resolved any dis- healthy individuals, the dorsalis pedis, posterior tibial, agreement in classification by consensus. and femoral pulses are not palpable 8.1%, 2.9%, and 0% Of the 17 studies identified, 7 were graded level 37 9-15 16-20 of the time, respectively (Table 3), findings that are con- 1, 5 were graded level 2, and 5 were graded level 35 3.21-25 Four studies10,11,16,21 were excluded from the sistent across all age groups. Even when a physician can- analysis of the pulse examination because each de- not palpate one of the pedal pulses of a healthy indi- fined as abnormal the absence of only 1 of the 2 pedal vidual, however, it is usually audible by a Doppler pulses, a common finding in healthy individuals (see flowmeter, the dorsalis pedis artery being congenitally below) and a biologically implausible sign of dis- absent in only 2% of extremities and the posterior tibial ease (lower-extremity ischemia, in any of the upper in 0.1%.39,40 Anatomists dissecting normal feet have found 2 segments, should cause both pedal pulses to dis- that when the dorsalis pedis artery is small or absent, the appear). Level 3 studies and other citations may ap- posterior tibial artery is prominent; when the posterior pear in the discussion if they provide original de- tibial artery is small, the dorsalis pedis is prominent.41 scriptions of physical findings, unique insights, or data that support findings from level 1 and 2 studies. How- These normal patterns of collateral circulation not only ever, we used only level 1 and 2 studies for calcula- help explain why clinicians use whichever pedal pulse tions of sensitivity, specificity, and likelihood ratios has the highest blood pressure to calculate the AAI, but (LRs). also why only 0.7% of normal extremities are missing both Data were expressed as sensitivity, specificity, pedal pulses (Table 3). positive and negative LRs, and the k statistic accord- Consistent with these anatomic studies and inves- ing to traditional definitions.26 If a particular LR, posi- tigations in healthy subjects, the absence of both pedal tive or negative, has a value close to 1, that outcome pulses has been shown to be a powerful predictor for the of the test is unhelpful in making diagnostic deci- presence of vascular disease (AAI,0.9) in the extremity sions at the bedside.27 examined (LR+=9.0-44.6; Table 4). For definitions of disease that include only the most severe cases (AAI,0.5), however, the positive LRs are lower (LR+=3.0-3.8), prob- ably because of diminished specificity (ie, many pa- (dorsalis pedis and posterior tibial arteries) with a hand- tients with AAIs between 0.5 and 0.9 also lack pedal held Doppler flowmeter and dividing it by the blood pres- pulses). sure in the brachial artery. In healthy individuals, the AAI Nevertheless, up to about one third of patients with is greater than 0.97 (this cutoff represents the lower 2.5% disease, sometimes at limb-threatening levels (ie, of measurements from large numbers of young, non- AAI,0.5),12 have at least 1 palpable pedal pulse (sensi- smoking, asymptomatic individuals).6-9 Values less than tivity, 0.63-0.95) (Table 4).