Evaluation of the one-minute exercise test to detect peripheral arterial disease

Exercise testing criteria to diagnose lower extremity peripheral artery disease assessed by computed-tomography angiography

BACKGROUND

The sensitivity and specificity of exercise testing have never been studied simultaneously against an objective quantification of arterial stenosis. Aims were to define the sensitivity and specificity of several exercise tests to detect peripheral artery disease (PAD), and to assess whether or not defined criteria defined in patients suspected of having a PAD show a difference dependent on the resting ABI.

METHODS

In this prospective study, consecutive patients with exertional limb pain referred to our vascular center were included. All patients had an ABI, a treadmill exercise-oximetry test, a second treadmill test (both 10% slope; 3.2km/h speed) with post-exercise pressures, and a computed-tomography-angiography (CTA). The receiver-operating-characteristic curve was used to define a cut-off point corresponding to the best area under the curve (AUC; [CI95%]) to detect arterial stenosis ≥50% as determined by the CTA.

RESULTS

Sixty-three patients (61+/-11 years-old) were included. Similar AUCs from 0.72[0.63-0.79] to 0.83[0.75-0.89] were found for the different tests in the overall population. To detect arterial stenosis ≥50%, cut-off values of ABI, post-exercise ABI, post-exercise ABI decrease, post-exercise ankle pressure decrease, and distal delta from rest oxygen pressure (DROP) index were ≤0.91, ≤0.52, ≥43%, ≥20mmHg and ≤-15mmHg, respectively (p<0.01). In the subset of patients with an ABI >0.91, cut-off values of post-exercise ABI decrease (AUC = 0.67[0.53-0.78]), and DROP (AUC = 0.67[0.53-0.78]) were ≥18.5%, and ≤-15mmHg respectively (p<0.05).

CONCLUSION

Resting ABI is as accurate as exercise testing in patients with exertional limb pain. Specific exercise testing cut-off values should be used in patients with normal ABI to diagnose PAD.

Comparison of different exercise ankle pressure indices in the diagnosis of peripheral artery disease

Although the resting ankle-brachial index (ABI) is commonly used as a tool to diagnose peripheral artery disease (PAD), several additional indices measured after exercise may have increased sensitivity for identifying PAD. The aim of this study was to determine the utility of resting ABI and three post-exercise physiological parameters for diagnosing PAD confirmed by arterial imaging studies. For each qualifying study, we assessed the performance measures for identifying PAD for resting ABI < 0.90, exercise ABI < 0.90, a decrease in ABI > 20% with exercise, and a decrease in ankle pressure > 30 mmHg with exercise. Of the 199 exams that met our inclusion criteria, imaging showed a > 75% stenotic lesion in at least one limb in 138 (69%) of patients. For stenoses > 75%, resting ABI < 0.90 had a sensitivity of 64% (95% CI: 56-72%) and exercise ABI < 0.90 had a sensitivity of 88% (95% CI: 82-93%). The sensitivity for a post-exercise ABI decrease > 20% was 67% (95% CI: 59-75%) and the sensitivity for a decrease in ankle pressure > 30 mmHg was 4% (95% CI: 2-9%). For individuals with a normal resting ABI but stenotic lesions > 75% confirmed by imaging (n=49), the addition of exercise ABI testing correctly identified an additional 25% of this population. Overall, exercise ABI < 0.90 exhibits a greater sensitivity for detecting PAD compared to resting ABI. Furthermore, exercise ABI < 0.90 had added clinical utility in patients with normal resting ABIs and was superior to other commonly used exercise indices.

Noninvasive Peripheral Artery Disease Screening Tools: A Deficient Knowledge among French Vascular Residents from 4 Medical Schools

BACKGROUND

Ankle-brachial index (ABI) at rest, postexercise ABI, and toe-brachial index (TBI) are essential diagnostic tools recommended for peripheral artery disease (PAD) diagnosis. Our study investigates the level of knowledge on these 3 tests among vascular medicine residents from 4 French medical schools in France.

METHODS

We included 19 vascular medicine residents in a cross-sectional study. During an annual obligatory seminar, all residents accepted to fill 3 questionnaires concerning knowledge about these 3 tests.

RESULTS

All residents accepted to fill 3 questionnaires. None of the residents correctly knows how to perform all pressure measurements (ABI, postexercise ABI, and TBI). Two residents had the knowledge to perform the whole ABI at rest procedure, whereas no resident had the knowledge to perform neither the postexercise ABI (P = 0.48) nor the TBI (P = 0.48). Twelve residents correctly completed the question regarding the interpretation of ABI at rest, whereas 2 correctly completed the postexercise ABI question (P = 0.001) and 4 the TBI question (P = 0.02). The number of residents who have performed more than 20 measurements is higher regarding ABI at rest than postexercise ABI and TBI (84%, 5%, and 37% respectively; P < 0.001 and P = 0.006 respectively) and significantly less often in postexercise ABI than TBI (5% vs. 37%; P = 0.04).

CONCLUSIONS

This study shows for the first time that residents' knowledge of pressure measurements (resting-ABI, postexercise ABI, and TBI) of 4 French medical school are insufficient although the importance of pressure measurement has been strongly highlighted by the newly released PAD guidelines (2016) for PAD diagnosis.

Ankle-Brachial Index Testing at the Time of Stress Testing in Patients Without Known Atherosclerosis

BACKGROUND

Individuals referred for stress testing to identify coronary artery disease may have nonobstructive atherosclerosis, which is not detected by stress tests. Identification of increased risk despite a negative stress test could inform prevention efforts. Abnormal ankle-brachial index (ABI) is associated with increased cardiovascular risk.

HYPOTHESIS

Routine ABI testing in the stress laboratory will identify unrecognized peripheral arterial disease in some patients.

METHODS

Participants referred for stress testing without known history of atherosclerotic disease underwent ABI testing (n = 451). Ankle-brachial index was assessed via simultaneous arm and leg pressure using standard measurement, automated blood-pressure cuffs at rest. Ankle-brachial index was measured after exercise in 296 patients and 30 healthy controls. Abnormal postexercise ABI was defined as a >20% drop in ABI or fall in ankle pressure by >30 mm Hg.

RESULTS

Overall, 2.0% of participants had resting ABI ≤0.90, 3.1% had ABI ≥1.40, and 5.5% had borderline ABI. No patient with abnormal or borderline ABI had an abnormal stress test. Participants who met peripheral arterial disease screening criteria (age ≥65 or 50-64 with diabetes or smoking) tended toward greater frequency of low ABI (2.9% vs 1.0%; P = 0.06) and were more likely to have borderline ABI (0.91 to 0.99; 7.8% vs 2.9%; P = 0.006). Postexercise ABI was abnormal in 29.4% of patients and 30.0% of controls (P not significant).

CONCLUSIONS

Ankle-brachial index screening at rest just before stress testing detected low ABI in 2.0% of participants, all of whom had negative stress tests.

Atypical leg symptoms: does routine measurement of the ankle brachial pressure index (ABPI) in primary care benefit patients?

Background : Managing patients with atypical leg symptoms in primary care can be problematic. Determining the ankle brachial pressure index (ABPI) may be readily performed to help diagnose peripheral arterial disease, but is often omitted where signs and symptoms are unclear. Question: Does routine measurement of ABPI in patients with atypical leg symptoms aid management increase satisfaction and safely reduce hospital referral? Methodology: Patients with atypical leg symptoms but no skin changes or neurological symptoms underwent clinical review and Doppler ABPI measurement (suspicious finding ≤ 1.0). Testing was performed by the same doctor (study period: 30 months). Patient outcomes were determined from practice records, hospital letters and a telephone survey. Results : The study comprised 35 consecutive patients (males: N = 15), mean age 64 years (range: 39-88). Presentation included pain, cold feet, cramps, irritation and concerns regarding circulation. Prior to ABPI measurement, referral was considered necessary in 10, not required in 22 and unclear in 3. ABPI changed the referral decision in 10 (29%) and confirmed the decision in 25 (71%). During the study, 10 (29%) patients were referred (9 vascular, 1 neurology). Amongst the vascular referrals, significant peripheral arterial disease has been confirmed in six patients. A further two patients are under review and one did not attend. To date, lack of referral in patients with atypical leg symptoms but a normal ABPI has not increased morbidity. Current status was assessed by telephone review in 16/35 (46% contact rate; mean 18 months, range 2-28). Fifteen patients (94%) appreciated that their symptoms had been quickly and conveniently assessed, 8/11 (73%) with a normal ABPI were reassured by their result and in 8/11 symptoms have resolved. Discussion/Conclusion: APBI conveniently aids management of atypical leg symptoms by detecting unexpected peripheral arterial disease, avoids /confirms the need for referral, reassures patients and guides reassessment. This study suggests ABPI should be used more widely.

Discordant Diagnosis of Lower Extremity Peripheral Artery Disease Using American Heart Association Postexercise Guidelines

To determine whether postexercise criteria for peripheral artery disease (PAD) diagnosis recommended by the American Heart Association (AHA) identifies the same group of PAD patients.Diagnosis of PAD is performed using ankle-brachial index at rest (resting-ABI). When resting-ABI is not contributive, an AHA scientific statement recommend to use 1 of 2 following criteria: a postexercise ABI decrease of greater than 20% or a postexercise ankle pressure decrease of greater than 30 mm Hg.Between 1996 and 2012, 31,663 consecutive patients underwent lower-extremity arterial study at Mayo Clinic. Among them, only unique patients who had exercise treadmill testing were analyzed. In this retrospective analysis, resting-ABI, postexercise ABI, and postexercise decrease of ankle pressure measured at 1-minute were measured in each patient. We conducted an analysis of agreement between postexercise criteria expressing the agreement separately for the positive and the negative ratings. Twelve thousand three hundred twelve consecutive patients were studied with a mean age of 67 ± 12 years, 61% male. According to resting-ABI, 4317 (35%) patients had PAD. In the whole population, if a clinician diagnoses "PAD" with 1 postexercise criterion, the probability that other clinicians would also diagnose "PAD" is 74.3%. If a clinician diagnoses "no PAD", the probability that other clinicians would also diagnose "no PAD" is 82.4%. In the patients to be of potential benefit from treadmill test when the resting-ABI > 0.90, if a clinician diagnoses "PAD" with 1 postexercise criterion, the probability that other clinicians would also diagnose "PAD" is 58.4% whereas if a clinician diagnoses "no PAD," the probability that other clinicians would also diagnose "no PAD" is 87.5%.Postexercise criteria do not identify the same group of PAD patients. In our opinion, postexercise criteria to define PAD deserve additional study.

Society for Vascular Surgery practice guidelines for atherosclerotic occlusive disease of the lower extremities: management of asymptomatic disease and claudication

Peripheral arterial disease (PAD) continues to grow in global prevalence and consumes an increasing amount of resources in the United States health care system. Overall rates of intervention for PAD have been rising steadily in recent years. Changing demographics, evolution of technologies, and an expanding database of outcomes studies are primary forces influencing clinical decision making in PAD. The management of PAD is multidisciplinary, involving primary care physicians and vascular specialists with varying expertise in diagnostic and treatment modalities. PAD represents a broad spectrum of disease from asymptomatic through severe limb ischemia. The Society for Vascular Surgery Lower Extremity Practice Guidelines committee reviewed the evidence supporting clinical care in the treatment of asymptomatic PAD and intermittent claudication (IC). The committee made specific practice recommendations using the GRADE (Grades of Recommendation Assessment, Development and Evaluation) system. There are limited Level I data available for many of the critical questions in the field, demonstrating the urgent need for comparative effectiveness research in PAD. Emphasis is placed on risk factor modification, medical therapies, and broader use of exercise programs to improve cardiovascular health and functional performance. Screening for PAD appears of unproven benefit at present. Revascularization for IC is an appropriate therapy for selected patients with disabling symptoms, after a careful risk-benefit analysis. Treatment should be individualized based on comorbid conditions, degree of functional impairment, and anatomic factors. Invasive treatments for IC should provide predictable functional improvements with reasonable durability. A minimum threshold of a >50% likelihood of sustained efficacy for at least 2 years is suggested as a benchmark. Anatomic patency (freedom from restenosis) is considered a prerequisite for sustained efficacy of revascularization in IC. Endovascular approaches are favored for most candidates with aortoiliac disease and for selected patients with femoropopliteal disease in whom anatomic durability is expected to meet this minimum threshold. Conversely, caution is warranted in the use of interventions for IC in anatomic settings where durability is limited (extensive calcification, small-caliber arteries, diffuse infrainguinal disease, poor runoff). Surgical bypass may be a preferred strategy in good-risk patients with these disease patterns or in those with prior endovascular failures. Common femoral artery disease should be treated surgically, and saphenous vein is the preferred conduit for infrainguinal bypass grafting. Patients who undergo invasive treatments for IC should be monitored regularly in a surveillance program to record subjective improvements, assess risk factors, optimize compliance with cardioprotective medications, and monitor hemodynamic and patency status.