The Effect of Post-Exercise Ankle-Brachial Index on Lower Extremity Revascularization

Exercise therapy for chronic symptomatic peripheral artery disease

All guidelines worldwide strongly recommend exercise as a pillar of the management of patients affected by lower extremity peripheral artery disease (PAD). Exercise therapy in this setting presents different modalities, and a structured programme provides optimal results. This clinical consensus paper is intended for clinicians to promote and assist for the set-up of comprehensive exercise programmes to best advice in patients with symptomatic chronic PAD. Different exercise training protocols specific for patients with PAD are presented. Data on patient assessment and outcome measures are narratively described based on the current best evidence. The document ends by highlighting disparities in access to supervised exercise programmes across Europe and the series of gaps for evidence requiring further research.

Exercise therapy for chronic symptomatic peripheral artery disease

All guidelines worldwide strongly recommend exercise as a pillar in the management of patients affected by lower extremity peripheral artery disease (PAD). Exercise therapy in this setting presents different modalities, and a structured programme provides optimal results. This clinical consensus paper is intended to promote and assist the set up of comprehensive exercise programmes and best advice for patients with symptomatic chronic PAD. Different exercise training protocols specific for patients with PAD are presented. Data on patient assessment and outcome measures are described based on the current best evidence. The document ends by highlighting supervised exercise programme access disparities across Europe and the evidence gaps requiring further research.

Exercise Therapy for Chronic Symptomatic Peripheral Artery Disease: A Clinical Consensus Document of the European Society of Cardiology Working Group on Aorta and Peripheral Vascular Diseases in Collaboration With the European Society of Vascular Medicine and the European Society for Vascular Surgery

All guidelines worldwide strongly recommend exercise as a pillar in the management of patients affected by lower extremity peripheral artery disease (PAD). Exercise therapy in this setting presents different modalities, and a structured programme provides optimal results. This clinical consensus paper is intended to promote and assist the set up of comprehensive exercise programmes and best advice for patients with symptomatic chronic PAD. Different exercise training protocols specific for patients with PAD are presented. Data on patient assessment and outcome measures are described based on the current best evidence. The document ends by highlighting supervised exercise programme access disparities across Europe and the evidence gaps requiring further research.

Comparison of resting/postexercise ankle-brachial index and transcutaneous partial pressure of oxygen for noninvasive diagnosis of peripheral artery disease in type 2 diabetes mellitus

Background Type 2 diabetes

Type 2 diabetes mellitus (T2DM) is a strong risk factor for peripheral artery disease (PAD) and PAD diagnosis in T2DM may indicate coexisting coronary artery disease as well. Postexercise ankle brachial index (ABI) and transcutaneous partial pressure of oxygen (TcPO2) have not been evaluated for PAD diagnosis among Indian T2DM patients. This study aimed to evaluate the performance of resting + postexercise(R + PE) ABI and R + PE-TcPO2 for PAD diagnosis among T2DM patients at increased PAD risk, using colour duplex ultrasound (CDU) as reference standard.

Methods

This prospectively conducted diagnostic accuracy study involved T2DM patients at increased PAD risk. R-ABI≤0.9 or PE-ABI decline >20% from resting value in those with R-ABI between 0.91 and 1.4, R-TcPO2 <30 mm Hg or PE decline of TcPO2 to <30 mm Hg in those with R-TcPO2 ≥30 mm Hg, CDU showing >50% stenosis or complete occlusion of lower extremity arteries constituted PAD.

Results

Among 168 patients enrolled, R + PE-ABI diagnosed PAD in 19(11.3%), R + PE-TcPO2 in 61 (36.3%) and 17 (≈10%) had PAD finally confirmed by CDU. Sensitivity, specificity, PPV and NPV of R + PE-ABI for PAD diagnosis were 82.3%, 96.7%, 73.7% and 98% and that of R + PE-TcPO2 were 76.5%, 68.2%, 21.3% and 96.2%, respectively. PE-ABI increased the sensitivity of ABI by ≈ 18% and had 100% PPV for PAD. When both ABI and TcPO2 (R + PE tests) were normal, PAD could be safely excluded in 88% of patients.

Conclusion

PE-ABI should be routinely employed and TcPO2(R/PE) is unreliable as a stand-alone test for PAD detection among moderate to high risk T2DM patients.

Tibio-pedal arterial pressure assessment during endovascular intervention to improve quality-of-life in patients with intermittent claudication

Objective

The aim of this study is to compare the quality-of-life (QOL) outcomes and the tibio-pedal arterial pressure post-endovascular intervention.

Background

Physiological assessment of peripheral arterial lesions is infrequently performed during endovascular interventions.

Materials and methods

We retrospectively reviewed all 343 patients with intermittent claudication who underwent an endovascular intervention via tibio-pedal artery access from October 2018 to May 2021. The baseline and post-intervention tibio-pedal arterial pressures from the pedal sheaths were measured. QOL was assessed using a pre-validated Walking Impairment Questionnaire (WIQ) score before and at 30-day after intervention. We compared the baseline tibio-pedal arterial pressure, post-intervention tibio-pedal arterial pressure, delta pressure (post-intervention minus baseline), baseline WIQ scores, 30-day WIQ scores, and delta score (30-day minus baseline).

Results

All 343 patients had successful tibio-pedal accesses. The average tibio-pedal arterial pressure at baseline was 87.0 ± 1.8 mmHg vs. 135.5 ± 1.7 mmHg post-intervention (p &lt; 0.001). Average baseline and 30-day WIQ scores were summation (99.8 ± 3.3 vs. 115.0 ± 3.1, p &lt; 0.001), walking distance (35.7 ± 1.3 vs. 42.5 ± 1.3, p &lt; 0.001), walking speed (21.1 ± 0.9 vs. 23.6 ± 0.8, p = 0.036), stair climbing (4.7 ± 1.4 vs. 24.2 ± 1.4, p = 0.019), and symptoms (18.8 ± 0.2 vs. 20.1 ± 0.2, p &lt; 0.001), respectively. When comparing the increased post-intervention tibio-pedal arterial pressure &lt;60 mmHg vs. ≥60 mmHg, the average delta WIQ scores were all significantly improved with summation (10.0 ± 3.9 to 25.8 ± 5.5, p = 0.01), walking distance (4.1 ± 1.7 to 9.8 ± 2.5, p = 0.02), walking speed (1.5 ± 1.1 to 4.3 ± 1.5, p = 0.02), stair climbing (2.3 ± 1.8 to 9.4 ± 2.5, p = 0.02), and symptoms (1.0 ± 0.3 to 1.8 ± 0.4, p = 0.04), respectively.

Conclusion

Increasing the post-intervention tibio-pedal arterial pressure by 60 mmHg can enhance QOL as suggested by improvement of WIQ scores.

Artificial intelligence for the evaluation of peripheral artery disease using arterial Doppler waveforms to predict abnormal ankle-brachial index

BACKGROUND

Patients with peripheral artery disease (PAD) are at increased risk for major adverse limb and cardiac events including mortality. Developing screening tools capable of accurate PAD identification is a necessary first step for strategies of adverse outcome prevention. This study aimed to determine whether machine analysis of a resting Doppler waveform using deep neural networks can accurately identify patients with PAD.

METHODS

Consecutive patients (4/1/2015 - 12/31/2020) undergoing rest and postexercise ankle-brachial index (ABI) testing were included. Patients were randomly allocated to training, validation, and testing subsets (70%/15%/15%). Deep neural networks were trained on resting posterior tibial arterial Doppler waveforms to predict normal (> 0.9) or PAD (⩽ 0.9) using rest and postexercise ABI. A separate dataset of 151 patients who underwent testing during a period after the model had been created and validated (1/1/2021 - 3/31/2021) was used for secondary validation. Area under the receiver operating characteristic curves (AUC) were constructed to evaluate test performance.

RESULTS

Among 11,748 total patients, 3432 patients met study criteria: 1941 with PAD (mean age 69 ± 12 years) and 1491 without PAD (64 ± 14 years). The predictive model with highest performance identified PAD with an AUC 0.94 (CI = 0.92-0.96), sensitivity 0.83, specificity 0.88, accuracy 0.85, and positive predictive value (PPV) 0.90. Results were similar for the validation dataset: AUC 0.94 (CI = 0.91-0.98), sensitivity 0.91, specificity 0.85, accuracy 0.89, and PPV 0.89 (postexercise ABI comparison).

CONCLUSION

An artificial intelligence-enabled analysis of a resting Doppler arterial waveform permits identification of PAD at a clinically relevant performance level.

Validation of a Standardised Duplex Ultrasound Classification System for the Reporting and Grading of Peripheral Arterial Disease

INTRODUCTION

Duplex ultrasound (DUS), a non-invasive means of arterial mapping, allows for reliable diagnosis of peripheral arterial disease (PAD). One of our authors (CPO), developed a standardised DUS-based scoring system, devised for rapid detection and reporting of PAD. The purpose of this study is to validate this system, determining diagnostic performance both overall, and per disease severity.

METHODS

250 participants were recruited, based on diagnosis (N = 125), or absence of PAD (N = 125) from GP registers. Right and left legs per subject were handled as independent readings, determining actual PAD status via ABPI <0.9, and then further grading disease severity using suggested ABPI ranges. Data were excluded if no corresponding ABPI value was obtained per DUS-determination, or if the ABPI reading was >1.4, owing to risk of false negatives due to incompressible vessels. Diagnostic sensitivity and specificity were obtained overall, and per severity classification. Furthermore, interrater agreement between ABPI- and DUS-determined PAD severity was determined by linear weighted Cohen's Kappa.

RESULTS

The sensitivity and specificity in the detection of disease overall was 81.0% (95% CI 73.4 - 87.2%) and 86.3% (95% CI 82.3 - 89.8%), respectively. From mild to severe PAD, sensitivity increased from 71.1% (95% CI 55.7 - 83.6%) to 89.3% (95% CI 71.8 - 97.7%). Furthermore, a Cohen Kappa value of 0.63 (95% CI 0.57 - 0.69) was obtained, indicating moderate agreement between the two diagnostic methods.

CONCLUSIONS

Findings in this study validate the diagnostic performance of the standardised DUS scoring system, as well as its capacity to grade severity of disease, offering a potential tool for the identification of PAD in the community / research settings following initial screening methods. Confirmatory work could include a comparison of DUS-determined disease with gold-standard methods of non-invasive angiography, and novel tools such as toe-flex NIRS and multi-site photoplethysmography.

Principal predictors of major adverse limb events in diabetic peripheral artery disease: A narrative review

Background and aims

The increasing prevalence of diabetes mellitus is causing a massive growth of peripheral artery disease incidences, a disabling complication of diabetic atherosclerosis, which leads often to the amputation of the affected limb. Critical limb ischemia is the terminal disease stage, which requires a prompt intervention to relieve pain and save limbs. However, patients undergoing revascularization often suffer from cardiovascular, cerebrovascular and major adverse limb events with poor outcomes. Furthermore, the same procedure performed in apparently similar patients has various outcomes and lack of an outcome predictive support causes a high lower limb arterial revascularization rate with disastrous effects for patients. We collected the main risk factors of major adverse limb events in a more readable and immediate format of the topic, to propose an overview of parameters to manage effectively peripheral artery disease patients and to propose basics of a new predictive tool to prevent from disabling vascular complications of the disease.

Methods

Most recent and updated literature about the prevalence of major adverse limb events in peripheral artery disease was reviewed to identify possible main predictors.

Results

In this article, we summarized major risk factors of limb revascularization failure and disabling vascular complications collecting those parameters principally responsible for major adverse limb events, which provides physio-pathological explanation of their role in peripheral artery disease.

Conclusion

We evaluated and listed a panel of possible predictors of MALE (Major Adverse Limb Event) in order to contribute to the development of a predictive score, based on a summary of the main risk factors reported in scientific articles, which could improve the management of peripheral artery disease by preventing vascular accidents.

Calf and non-calf hemodynamic recovery in patients with arterial claudication: Implication for exercise training

BACKGROUND

Previous studies in patients with arterial claudication have focused on calf hemodynamic recovery. We hypothesized that the duration of hemodynamic recovery with TcpO2 at calf and non-calf levels would be shorter than 10 min. We analyzed the factors that influence the recovery time.

METHODS

We monitored limb changes minus chest changes from rest (DROP) of transcutaneous oximetry on buttocks, thighs and calves, during and following a treadmill test (3.2 km/h; 10% grade). We calculated the time required to reach 50% (50%RT) and 10% (90%RT) of minimal DROP value (DROPm) from walking cessation. Regression analyses were used to determine the factors associated to 50%RT and 90%RT.

RESULTS

Of the 132 patients studied, 18.2% reported isolated non-calf pain by history. Of the 792 recovery time values, only 3 (0.4%) and 23 (2.9%) were in excess of 10 min for 50%RT and for 90%RT, respectively. A weak correlation was found between each of the 792 DROPm and 50%RT (r = -0.270, p < 0.001) as well as for 90%RT (r = -0.311 p < 0.001). Lowest DROPm and BMI (but not age, sex, the use of beta-blockers, the duration of the walking period) were associated to both 50%RT and 90%RT.

CONCLUSION

Although recovery duration correlates significantly with the severity of ischemia of the same location, a wide discrepancy exists and the longest recovery time does not always correlate to the localization of the most severe ischemia. Non-calf ischemia should be measured when one aims at objectifying the biological effects of exercise or the effects of treatments on recovery from exercise.

Diagnosis and Management of Peripheral Artery Diseases

Распространенность заболеваний периферических артерий (ЗПА) во всем мире достигает порядка 200 миллионов человек. Самым частым клиническим проявлением ЗПА является перемежающая хромота, возникающая вследствие недостаточного кровоснабжения пораженной конечности. В настоящем обзоре литературы обобщены и систематизированы последние достижения в области диагностики и лечения пациентов с перемежающей хромотой. Тщательный сбор анамнеза и физикальное обследование являются первоочередными мероприятиями для установления предварительного диагноза и направлены на дифференциацию сосудистых и нейрогенных причин перемежающей хромоты. Лодыжечно-плечевой индекс относится к наиболее часто используемым методам скрининга и диагностики ЗПА. Основу лечения составляют четыре взаимодополняющих подхода: немедикаментозное и лекарственное лечение для купирования симптомов хронической ишемии, фармакотерапия для вторичной профилактики сердечно-сосудистых осложнений, открытая или эндоваскулярная реваскуляризация для увеличения дистанции безболевой ходьбы. Недавнее исследование COMPASS продемонстрировало преимущества комбинированного применения 2,5 мг ривароксабана дважды в день и аспирина в части снижения уровня неблагоприятных сердечно-сосудистых событий, при этом отмечался более высокий риск геморрагических осложнений. На сегодняшний день цилостазол является единственным препаратом, обладающим доказанной терапевтической эффективностью в отношении перемежающей хромоты. Программы лечебной физкультуры под наблюдением врача либо в домашних условиях способствуют улучшению коллатерального кровообращения и увеличивают дистанцию ходьбы без боли. Назначение высоких доз статинов и антитромбоцитарных препаратов абсолютно обосновано всем пациентам с ЗПА. Ингибиторы ангиотензин-превращающего фермента обеспечивают дополнительное снижение кардиоваскулярных рисков, в особенности у пациентов с сахарным диабетом и артериальной гипертензией.

The prevalence of peripheral artery disease (PAD) worldwide reaches about 200 million people. The most frequent clinical manifestation of PAD is intermittent claudication, which occurs due to insufficient blood supply to the affected limb. This literature review summarizes and systematizes recent advances in the diagnosis and treatment of patients with intermittent claudication.Thorough case history collection and physical examination are the primary measures for making a preliminary diagnosis, which is aimed at differentiating the vascular and neurogenic causes of intermittent claudication. The ankle-shoulder index is one of the most commonly used methods for screening and diagnosing PAD. The basis of treatment consists of four complementary approaches: non-pharmacological and pharmacological treatment for the relief of symptoms of chronic ischemia, pharmacotherapy for the secondary prevention of cardiovascular complications, open or endovascular revascularization to increase the distance of pain-free walking. A recent COMPASS study demonstrated the benefits of combining 2.5 mg of rivaroxaban twice daily with aspirin in reducing adverse cardiovascular events, however there was a higher risk of hemorrhagic complications. Today, cilostazol is the only drug with proven therapeutic effectiveness against intermittent claudication. Physical therapy programs under the supervision of a doctor or at home help to improve collateral blood circulation and increase the walking distance without pain. The administration of high doses of statins and antiplatelet drugs is absolutely justified in all patients with PAD. Angiotensin converting enzyme inhibitors provide an additional reduction in cardiovascular risks, especially in patients with diabetes and hypertension.

Involvement of microcirculation in critical ischemia: how to identify it?

Critical limb ischemia represents the most severe pattern of peripheral arterial disease (PAD) associated with the high risk of major amputation, cardiovascular events and death. The diagnosis and management of critical limb ischemia (CLI) is often challenging. Systolic ankle and toe pressure measurements are considered to be the basic techniques for the identification of PAD. However, they provide rough insight into the dependent local tissue perfusion. Furthermore, those techniques do not enable investigation of microcirculation which has crucial role in the pathogenesis of CLI. Some patients with mild deterioration of macrocirculation develop CLI if microcirculation is affected. Investigation of perfusion on macro- and local microcirculatory level enables more effective treatment: revascularization of the angiosome-related artery. The technologies capable of assessing limb tissue oxygenation or perfusion on microcirculatory level enable direct assessment of distant tissue oxygenation. Transcutaneous oxygen tension (TcPO2) measurement which was introduced in clinical practice represents one of the objective criteria for the diagnosis of CLI. Main weakness of this technique as well as laser Doppler flow measurement is low penetrance from the skin surface. Measurement of tissue blood flow on microcirculatory level can be performed with indocyanine green fluorescent imaging (ICG), contrast-enhanced magnetic resonance and vital microscopy. ICG is promising method which provides excellent informative image of tissue perfusion. However, it offers little quantitative information. Investigation of microcirculation in patients with CLI is of outmost importance because it enables insight in local tissue perfusion and oxygenation, which represents the basis of identification of most ischemic regions and provide more successful angiosome related revascularization of an affected artery.

How To Assess a Claudication and When To Intervene

PURPOSE OF THE REVIEW

Peripheral artery disease (PAD) affects close to 200 million people worldwide. Claudication is the most common presenting symptom for patients with PAD. This review summarizes the current diagnostic and treatment options for patients with claudication. Comprehensive history and physical examination in order to differentiate between claudication secondary to vascular disease vs. neurogenic causes is paramount for initial diagnosis. Ankle-brachial index is the most commonly used test for screening and diagnostic purposes. Treatment consists of four different approaches, which are best utilized in combination: non-pharmacological treatment for claudication improvement, pharmacological treatment for claudication improvement, pharmacological treatment for secondary risk reduction, and interventional treatment for claudication improvement.

RECENT FINDINGS

Cilostazol is the only Food and Drug Administration (FDA)-approved agent for symptomatic treatment of claudication. Supervised exercise programs provide the maximum benefit for claudication improvement, but home-based exercise programs are an alternative. High-intensity statins and an antiplatelet agent should be prescribed to all patients with PAD. Angiotensin-converting-enzyme inhibitors can provide additional risk reduction, especially in patients with diabetes or hypertension. Rivaroxaban of low dosage (2.5 mg twice daily) in combination with aspirin further decreases cardiovascular risk, but this reduction comes at the cost of higher bleeding risk. Peripheral artery disease (PAD) is a form of atherosclerotic disease that affects hundreds of millions of people worldwide-one of its most common manifestations is intermittent claudication (IC), which results from insufficient blood flow to meet the metabolic demands of an affected extremity. This paper reviews the current literature regarding the workup, diagnosis, diagnostic modalities, treatment options, and management of intermittent claudication.

Functional hemodynamics assessment during endovascular Tibio-pedal retrograde intervention of peripheral arterial disease

OBJECTIVE

We sought to use a novel technique to measure the functional hemodynamics of peripheral arterial lesions during endovascular interventions.

BACKGROUND

Functional hemodynamics has not been thoroughly evaluated during endovascular interventions. The aim of our study is to evaluate the feasibility and the potential benefits of pedal pressures measurements from tibio-pedal access.

METHODS

We retrospectively reviewed 100 consecutive patients who underwent endovascular interventions via tibio-pedal artery access between October 3, 2018 and December 15, 2018. Baseline and postintervention pedal pressures from the pedal sheaths were measured. We also evaluated the pedal-brachial index (PBI) which is defined as the pedal sheath pressure divided by the simultaneously brachial cuff pressure. We compared baseline pedal pressures, postintervention pedal pressures, baseline PBI, postintervention PBI, % change of PBI ([postintervention PBI minus baseline PBI]/baseline PBI), and resting ankle-brachial index (ABI) versus baseline PBI in this cohort of patients.

RESULTS

All 100 patients had successful tibio-pedal artery access. Baseline pedal pressure was 70 + 30 mmHg with post intervention pedal pressure of 133 + 27 mmHg (p < .001). Baseline PBI was 0.75 + 0.24 with post intervention PBI of 1.09 + 0.19 (p < .001). The correlation coefficient of resting ABI vs. baseline PBI was 0.55. The % change of PBI was 63.2 + 52.4%. There was significant improvement of postintervention PBI when compared to baseline PBI in the majority of patients.

CONCLUSIONS

Obtaining pedal pressures and PBI from tibio-pedal access can be a feasible tool for endovascular interventions. This simple technique can provide us important functional hemodynamics information before and after peripheral revascularization.

Associations of exercise ankle-brachial index, pain-free walking distance and maximum walking distance with the Peripheral Artery Questionnaire: Finding from the PORTRAIT PAD Registry

An exercise ankle-brachial index (ABI) test can provide further insight into the functional significance of peripheral artery disease (PAD). The variability in its use, associated patient factors and its relation to patients' symptoms are unknown. From the international PORTRAIT registry, we identified 1131 patients with PAD. We fit a hierarchical logistic regression model, adjusting for patient factors, country and site, to examine predictors of and variation in ordering exercise ABI testing. We also examined the associations between test components and health status as quantified by the Peripheral Artery Questionnaire (PAQ) using semi-parametric regression methods. Testing was ordered in 22% in the United States versus 80% in the Netherlands and 90% in Australia. Testing was likely to be performed if the patient was male, younger, had typical symptoms and a higher resting ABI, with substantial variability across sites (median odds ratio=5.9, 95% CI: 3.2-19.5). Adjusting for country and site, the resting ABI and all exercise ABI metrics were associated with the PAQ Physical Limitation score. In addition, important components of the test, namely time to onset of claudication, pain-free walking distance (PFWD), and maximum walking distance (MWD), were also associated with PAQ Symptoms and Summary scores. More importantly, even after adjusting for resting ABI, a patient with a post-exercise ABI of 0.29 (25th percentile), compared to 0.61 (75th percentile), achieved 4.4 (95% CI: 0.4-8.4, p=0.031) points less on the PAQ Physical Limitation score. Exercise ABI test use is remarkably variable, and less used in the United States. Its data, specifically PFWD and MWD, might help in objectively assessing the impact of PAD on patients' functioning and quality of life.

Predictors of Change in the Ankle Brachial Index with Exercise

OBJECTIVE

A 20% or greater decrease in the ankle brachial index (ABI) with exercise is suggestive of peripheral artery disease (PAD), and could identify patients with an increased mortality risk. The predictors of a change in the ABI with exercise have received little attention.

METHODS

This was a cross-sectional analysis. Two hundred and sixty five participants of the San Diego Population Study with a resting ABI between 0.90 and 1.10 performed 50 heel raises and immediately had their ABIs measured again. The relationship between the change in the ABI with exercise and multiple potential risk prediction variables were examined using linear regression. In addition, the categorical percent change in the ABI with exercise was analysed by multinomial logistic regression.

RESULTS

The mean age of participants was 71.8 years, and 80.4% were female. At rest, the average ABI was 1.04 (SD 0.04) before and 0.94 (SD 0.13) after exercise; a mean decrease of 9.5%. In analyses of ABI change as a continuous variable, higher age, any smoking history, and a diagnosis of chronic obstructive pulmonary disease (COPD) were associated with a significant decrease in the ABI with exercise (p = .01, .04, and .03, respectively). Categorical analyses of the risk factors associated with a 20% or greater ABI decrease with exercise confirmed these results. Congestive heart failure was associated with an increased ABI with exercise (p = .04) in continuous ABI change analyses only.

CONCLUSIONS

Older age, a positive history of smoking, and a history of COPD were independently and significantly associated with a greater ABI decrease with exercise. These risk variables may help identify persons with subclinical PAD.

Predictors of an abnormal postexercise ankle brachial index: Importance of the lowest ankle pressure in calculating the resting ankle brachial index

BACKGROUND

The postexercise ankle-brachial index (ABI) is useful in patients with suspected peripheral arterial disease (PAD) and a normal resting ABI. Our objective was to determine the independent predictors of an abnormal postexercise ABI.

HYPOTHESIS

We hypothesized that the lowest ankle systolic pressure to calculate the resting ABI would be associated with an abnormal post-exercise ABI.

METHODS

Among 619 consecutive patients referred for suspected PAD, we calculated the postexercise ABI in patients with a normal resting ABI. An ABI <0.90 at rest was considered abnormal. We investigated 3 definitions of an abnormal postexercise ABI, defined as either <0.90, or >5% or >20% reduction compared with rest.

RESULTS

Using multivariate analysis, the lowest ABI (calculated using the lowest and not the highest ankle systolic pressure) was consistently the most powerful independent predictor of an abnormal postexercise ABI. Patients with an abnormal lowest resting ABI were significantly more likely to have an abnormal postexercise ABI, as well as a significantly greater reduction in the ABI compared with rest. The lowest ABI had a high specificity (95%) but low sensitivity (82%) for a postexercise ABI <0.90.

CONCLUSIONS

An abnormal lowest ABI (calculated with the lowest ankle systolic pressure) is the most important independent predictor of an abnormal ABI response to exercise in patients with a conventionally normal ABI. All such patients should be exercised and their ABI measured postexercise.

Discrepancies in Prevalence of Peripheral Arterial Disease between Lower Extremities at Rest and Postexercise

Background  Lower extremity peripheral arterial disease (PAD) is a common medical condition causing substantial morbidity. Limited data exist on whether discrepancies in PAD prevalence exist between the lower extremities using resting ankle-brachial indices (ABIs) and postexercise pressures. Objective  We predicted the prevalence of PAD between the lower extremities. Methods and Results  Consecutive patients who had undergone a noninvasive arterial lower extremity study at Mayo Clinic, Rochester, MN, between January 1996 and December 2012 with suspected PAD were retrospectively reviewed. We identified 12,312 consecutive patients who underwent an arterial lower extremity and an exercise treadmill study. Prevalence of PAD was assessed at rest and after exercise using two criteria: a resting ABI ≤ 0.90 and a postexercise pressure decrease of > 30 mm Hg. Mean age was 67 ± 12 years and there were 4,780 (39%) women studied. At rest, we found a higher prevalence of PAD on the left extremity (27.4%) compared with the right (24.6%) ( p  < 0.0001). After exercise, we found a higher prevalence of PAD on the right extremity (25.1%) compared with the left (19.0%) ( p  < 0.0001). These discrepancies between the prevalence of PAD at rest and after exercise were present in women and men. Conclusion  Using validated criteria of a resting ABI of ≤ 0.90 and postexercise ankle pressure decrease > 30 mm Hg, our results suggest that there is a significantly higher prevalence of PAD in the left lower extremity at rest, in contrast to a greater prevalence of abnormal postexercise testing in the right lower extremity. The reason(s) of these discrepancies remain to be studied.

Prognostic value of an increase in post-exercise ankle-brachial index

Prior studies have assessed the prognostic value of a decrease, not an increase, of the post-exercise ankle-brachial index (ABI) among patients with normal resting results. Thus, we sought to evaluate the prognostic significance of an increase in post-exercise ABI among these patients. From a single center vascular laboratory database between September 2005 and January 2010, we retrospectively identified 1437 consecutive patients with a normal resting ABI (1.00-1.40) and available post-exercise results. We classified them into group 1 (normal subjects; post-exercise ABI drop ⩽ 20%, 58%) and group 2 (post-exercise ABI increase, 42%) after excluding those with an ABI drop > 20% (peripheral artery disease) as they had known disease ( n=192). The primary outcome was to assess the risk of ischemic events, defined as a composite of unadjudicated death, stroke, or myocardial infraction (MACE). Associations between groups and outcomes were examined using multivariable Cox proportional hazard and propensity analyses. Both groups had similar prevalence of cardiovascular comorbidities. In unadjusted analysis, group 2 was more likely to have MACE ( p = 0.001). After adjusting for all baseline characteristics, an increase in post-exercise ABI compared to normal subjects was associated with a higher MACE (adjusted HR: 1.70, 95% CI: 1.14-2.53; p=0.009). This association stayed statistically significant after propensity matching (adjusted HR: 1.80, 95% CI: 1.17-2.76; p=0.007). This hypothesis-generating analysis showed that an increase in post-exercise ABI appears to identify a population with a higher risk for MACE. A prospective study of this association and mechanisms of risk should be conducted.

Resting and Post-Exercise Ankle-Brachial Index Measurements to Diagnose Asymptomatic Peripheral Arterial Disease in Middle Aged and Elderly Chronic Obstructive Pulmonary Disease Patients: A Pilot Study

BACKGROUND

Chronic obstructive pulmonary disease (COPD) patients are at risk for asymptomatic peripheral arterial disease (PAD) because smoking is a risk factor for COPD and PAD. The objectives of this study were to determine the proportion of COPD patients with asymptomatic PAD and to investigate whether the estimated risk of asymptomatic PAD in subjects with COPD differs using resting and exercise ankle-brachial index (ABI) in smokers.

METHODS

Using a cross-sectional study design, consecutive smokers > 50 years old were recruited over 2 months from the inpatient units and the outpatient clinics. Subjects previously diagnosed with PAD, unstable angina, recent (< 3 months) myocardial infarction or abdominal, intracranial, eye or lung surgery, and palliative care patients were excluded. Vascular risk factors, ABI (supine and post-3-minute walk supine), self-reported PAD symptoms, and spirometry were obtained. Two measurements of systolic blood pressure on all limbs were obtained using a sphygmomanometer and a Doppler ultrasound, and the ABI was calculated. Data were expressed as means ± standard deviation (SD). Dichotomous outcomes were assessed using Chi-square statistics; P-values of < 0.05 were considered significant.

RESULTS

Thirty patients with no previous diagnosis of PAD were recruited. Mean age was 67.7 years (SD: 10.5). Overall, 21 subjects (70%) had spirometry-proven COPD. Significant ABI for PAD (< 0.9) was seen in 7/21 COPD (33.5%) and 0/9 non-COPD subjects in the supine resting position (P = 0.07), and in 9/21 COPD (42.9%) vs. 0/9 non-COPD subjects after exercise (P = 0.03).

CONCLUSIONS

A significant proportion of patients with spirometry-proven COPD screened positive for asymptomatic PAD after exercise. Resting ABI may not be very sensitive to diagnose asymptomatic PAD in COPD subjects. ABI may be a reliable, sensitive and practical screening tool to assess cardiovascular risk in COPD patients. Future large-scale studies are required to confirm this finding.

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.