Reduction In Ankle-brachial Index Research Articles

Post-Exercise Ankle–Brachial Index Is Reduced in Healthy, Young Individuals at a Level Indicating Peripheral Artery Disease

In young patients referred for exercise-induced pain in the legs, false positive tests are a potential problem for the post-exercise ankle–brachial index (ABI) test when using the current American Heart Association guidelines for diagnosing peripheral artery disease (PAD). The present study aimed to investigate post-exercise ABI in healthy young people, and to explore whether the current diagnostic criteria for pathological ABI should be revised. Forty-eight volunteers (18–30 years) were included. Resting examinations included ABI and ultrasound of the external iliac artery. Post-exercise examinations after a treadmill load included ABI and ultrasound of the external iliac artery; after 0 min and after 3 min. A total of 60.5% of the participants had a post-exercise decrease in ABI > 20%. A total of 6.5% showed a decrease in ankle systolic blood pressure >30 mmHg. No significant association was observed between a change in blood flow in the external iliac artery and a reduction in ABI post-exercise. Analyses of the ultrasound recordings showed no turbulence in the external iliac artery. According to the results, a 20% decrease in ABI post-exercise seems to be a physiological condition present in young people. We support the need for a reassessment of the criteria for diagnosing PAD.

Abstract 15085: Modest Reduction in Ankle-Brachial Index Measurements and Risk of Major Adverse Limb Events Among 133,373 Veterans

Introduction: Low resting ankle-brachial index (ABI) serves as a non-invasive biomarker of poor limb outcomes. Whether modest decrements in ABI translate into higher risks of major adverse limb events (MALE) are unclear, particularly among women and minorities, because prior studies are small or lack racial diversity and incident outcomes. Methods: We analyzed data from participants in the Veterans Affairs Birth Cohort, a prospective, longitudinal cohort of veterans born between 1945-1965 with no clinical history of PAD prior to ABI testing. Participants were enrolled on or after 1/1/2000 and followed through 12/31/2016. The exposure was resting ABI and the outcome was MALE defined as limb revascularization or amputation based on VA and Medicare ICD-9/10 and CPT codes. Cox proportional hazards models assessed the association between ABI and MALE among black and white men and women. Models were adjusted for demographics and PAD risk factors ( Figure Legend ). Results: The analysis included 23,733 black men, 1,257 black women, 96,220 white men, and 2,813 white women. There were 14,431 MALE events. Risk for MALE across the ABI spectrum followed a j-shaped distribution ( Figure ). Both low and high ABIs were associated with an increased risk of MALE for black and white men and women ( Figure ). When we analyzed each sex/race group separately, as compared to a normal ABI measurement (1.11-1.20), a modestly reduced ABI (0.81-0.90) was associated with a significantly increased risk of MALE: black men HR adj , 2.17; 95% CI, 1.67-2.80; black women HR adj , 3,24; 95% CI, 1.21-8.69; white men HR adj , 3.04; 95% CI, 2.68-3.46; white women HR adj , 4.56; 95% CI, 1.73-11.99. Conclusions: In a large, diverse cohort of people free of prior PAD, a modest reduction in ABI was associated with a greater than two-fold increased risk of MALE for all sex/race groups. Further studies are needed to better understand why MALE occurs in this patient population despite only mildly reduced limb perfusion.

Abstract 19013: Longitudinal Changes in Ankle and Brachial Pressures in a Community Dwelling Population: Results From the Baltimore Longitudinal Study of Aging

Reduction in ankle-brachial index (ABI) is a marker of peripheral arterial disease (PAD) and is attributed to flow limiting lesions. It is unclear whether the major changes in blood pressure with aging affect ankle and brachial pressures differently and result in changes in ABI with advancing age. We studies 719 participants (2176 observations) from the Baltimore Longitudinal Study of Aging who were free of clinical cardiovascular (CV) disease at baseline. Ankle and brachial systolic blood pressures (SBP) and their index (ABI) were measured in both sides using oscillometric device (Colin VP2000) and averages of both sides were calculated. Linear mixed effects models were used with age expressed as Entry-Age and Follow up Time (Time) to test for non-linear longitudinal changes in these parameters. About 15% of the sample had diabetes at baseline, 3.5% were current and 38% were former smokers. Adjusting for diabetes, smoking status and anti-hypertensive medications, men had greater ABI than women (B= 0.02, P=<0.001) with no statistically significant differences in trajectories. ABI changed with aging with statistically significant Entry-age X Time terms (P<0.01). Model predicted values (Figure 1) shows a longitudinal decline in ABI after the age of 65. In men, this decline was a result of a longitudinal decline in ankle SBP vs plateauing brachial SBP. In women, the decline in ABI was a result of a greater increase in brachial SBP compared to ankle SBP. In conclusion, aging is independently associated with a decline in ABI in a healthy population free of clinical C disease. There were gender different in the pressure profiles yielding this reduction in ABI. A pathological reduction in ABI could represent an exaggerated age-associated hemodynamic alterations and not exclusively due to flow limiting lesions. Further studies are needed to understand the underlying alterations in arterial properties and the clinical significance of this subclinical reduction in ABI.

Preliminary evidence that low ankle-brachial index is associated with reduced bilateral hip extensor strength and functional mobility in peripheral arterial disease

Peripheral arterial disease (PAD) has been associated with skeletal muscle pathology, including atrophy of the affected muscles. In addition, oxidative metabolism is impaired, muscle function is reduced, and gait and mobility are restricted. We hypothesized that greater severity of symptomatic PAD would be associated with lower levels of muscle mass, strength, and endurance, and that these musculoskeletal abnormalities in turn would impair functional performance and walking ability in patients with PAD. We assessed 22 persons with intermittent claudication from PAD in this cross-sectional pilot study. Outcome assessments included initial claudication distance and absolute claudication distance via treadmill protocols and outcomes from the 6-minute walk (6MW). Secondary outcomes included one repetition maximum strength/endurance testing of hip extensors, hip abductors, quadriceps, hamstrings, plantar flexors, pectoral, and upper back muscle groups, as well as performance-based tests of function. Univariate and stepwise multiple regression models were constructed to evaluate relationships and are presented. Twenty-two participants (63.6% male; mean [standard deviation] age, 73.6 [8.2] years; range, 55-85 years) were studied. Mean (standard deviation) resting ankle-brachial index (ABI) was 0.54 ([0.13]; range, 0.28-0.82), and participants ranged from having mild claudication to rest pain. Lower resting ABI was significantly associated with reduced bilateral hip extensor strength (r = 0.54; P = .007) and reduced whole body strength (r = 0.32; P = .05). In addition, lower ABI was associated with a shorter distance to first stop during the 6MW (r = 0.38; P = .05) and poorer single leg balance (r = 0.44; P = .03). Reduced bilateral hip extensor strength was also significantly associated with functional outcomes, including reduced 6MW distance to first stop (r = 0.74; P = .001), reduced 6MW distance (r = 0.75; P < .001), and reduced total short physical performance battery score (worse function; r = 0.75; P = .003). Our results suggest the existence of a causal pathway from a reduction in ABI to muscle atrophy and weakness, to whole body disability represented by claudication outcomes and performance-based tests of functional mobility in an older cohort with symptomatic PAD. Longitudinal outcomes from this study and future trials are required to investigate the effects of an anabolic intervention targeting the muscles involved in mobility and activities of daily living and whether an increase in muscle strength will improve symptoms of claudication and lead to improvements in other functional outcomes in patients with PAD.

Predicting Coronary Heart Disease: From Framingham Risk Score to Ultrasound Bioimaging

Atherosclerosis is the leading cause of death and disabling disease. Whereas risk factors are well known and constitute therapeutic targets, they are not useful for prediction of risk of future myocardial infarction, stroke, or death. Therefore, methods to identify atherosclerosis itself have been tested and found useful (ie, coronary calcium detection by computed tomography scanning, reduction in ankle-brachial index, and ultrasound scanning of the carotid arteries). This review will focus on the latter technique. Detection of thickened carotid intima-media by ultrasound has been used in many large epidemiological studies, but although it has been found to be associated with increased risk of cardiovascular death, its clinical utility is limited. Detection of carotid plaque has, on the other hand, been found to be associated with a substantial risk of future events. Similarly, detection of plaque in the femoral arteries is associated with increased risk, and plaque in the femoral as well as carotid arteries predicts even higher risk. Furthermore, quantification of plaque size (plaque area), such as quantification of amount of coronary calcium on computed tomography scanning, improves predictability-the larger the plaques, the higher the risk. So far, studies using ultrasound all have been performed with 2-dimensional ultrasound imaging. Recently, 3-dimensional ultrasound imaging has been introduced, which allows for more accurate quantification of atherosclerosis. Small studies pioneering its use have indicated the utility of measuring changes in vessel-wall volume and plaque volume with respect to treatment effect. The High-Risk Plaque Initiative BioImage Study is currently investigating the predictive value of total carotid plaque volume with respect to prediction of future cardiovascular events.

Risk factors of accelerated progression of peripheral artery disease in hemodialysis

Ankle-brachial index (ABI) and brachial-ankle pulse wave velocity (baPWV) are markers for peripheral artery occlusive disease (PAOD) and arterial stiffness, respectively. The aims of this study were to assess whether PAOD and arterial stiffness progressed and to determine the risk factors for ABI and baPWV progression in patients on hemodialysis. This study enrolled 173 routine patients on hemodialysis. Both ABI and baPWV were measured by an ABI-form device at baseline and at 1 year of follow-up. Progression in ABI was defined as reduction in ABI exceeding 0.3, while baPWV measured at 1 year of follow-up exceeding that at baseline indicated baPWV progression. Comparison with baseline data showed increase in both prevalence of ABI < 0.9 (p = 0.045) and baPWV (p = 0.028) at 1 year of follow-up. Multiple linear regression analyses identified high fasting glucose and old age as independent factors of annual change in ABI and baPWV, respectively. Good control of blood sugar may contribute to delay the progression of peripheral artery disease in patients on hemodialysis.

Randomized comparison of effects of suture-based and collagen-based vascular closure devices on post-procedural leg perfusion

Vascular closure devices (VCD) are well established to facilitate hemostasis after cardiac catheterization procedures. However, impairment of flow due to the reduction of femoral artery diameter remains a major concern. The present study aims to evaluate leg perfusion before and after application of collagen- and suture-based vascular closure devices. A total of 366 patients (age: 64.3 years+/-10.7, male: 71.3%) were randomized to receive femoral access site closure with either a collagen-based closure device (group A) (n=214) or a suture-mediated device (group B) (n=152), immediately following coronary catheterization procedures. In all patients, the ankle-brachial-index (ABI) was measured before and the day after closure device application. In group A, mean ABI at baseline was 1.09+/-0.2, in group B 1.11+/-0.2. In both groups, there was a significant, albeit clinically not relevant, reduction in post-procedural ABI (group A: 1.04+/-0.2, p<0.01 vs baseline, group B: 1.06+/-0.2, p<0.01 vs baseline). DeltaABI was not different between both VCD groups (p=0.55). In patients with peripheral vascular disease (PVD), neither the Angioseal device (mean ABI at baseline 0.76+/-0.1) nor the Perclose-device (mean ABI at baseline 0.79+/-0.1) induced a remarkable impairment of leg perfusion (Angioseal: 0.77+/-0.1, p=0.9 vs baseline, Perclose: 0.78+/-0.1, p=1.0 vs baseline). Clinically, no aggravation of claudication was observed in the PVD patient group. Both vascular closure devices are not associated with clinically relevant reduction in ABI. There was no difference between the two groups with respect to the level of flow impairment. Both devices may be safely used in patients with reduced ABI.

A pilot study of l-arginine supplementation on functional capacity in peripheral arterial disease

Peripheral arterial disease (PAD) impairs walking capacity and is often associated with a profound endothelial vasodilator dysfunction, characterized by reduced bioactivity and/or synthesis of endothelium-derived nitric oxide (NO). Previous studies have suggested that dietary supplementation of L-arginine, the precursor of NO, improves endothelium-dependent vasodilation, limb blood flow and walking distance. However, these studies have been small, and have used large intravenous doses of L-arginine. The optimal dose of L-arginine has not been determined. Accordingly, this pilot study was conducted to establish the lowest effective oral dose of L-arginine to improve walking distance in preparation for the definitive study. Patients with PAD and intermittent claudication (n = 80) participated in this study. Eligibility criteria included: (1) ankle-brachial index (ABI) at rest < or = 0.90; (2) post-exercise reduction in ABI > or = 25%; and (3) difference in absolute claudication distance of < or = 25% between two consecutive treadmill tests. Treadmill testing was performed using the Skinner-Gardner protocol and community-based walking was assessed using the walking impairment questionnaire. Patients were randomly assigned to oral doses of 0, 3, 6 or 9 g of L-arginine daily in three divided doses for 12 weeks. Treadmill testing was performed prior to administration of the study drug and again after 12 weeks of treatment. The study drug was well tolerated, with no significant adverse effects of L-arginine therapy. The safety laboratory studies were unremarkable, except for a statistically significant reduction in hematocrit in the L-arginine-treated groups. There was no significant difference observed in absolute claudication distance between the groups. However, a trend was observed for a greater increase in walking distance in the group treated with 3 g L-arginine daily, and there was a trend for an improvement in walking speed in patients treated with L-arginine. This pilot study provided data for safety, for power calculation and for dosing for the larger definitive trial that is now underway.

Natural history of infrainguinal vein bypass stenoses: Early lesions increase the risk of thrombosis

To describe the natural history of stenoses in infrainguinal vein bypasses and to identify factors predicting outcome. Forty-two patients with non-revised vein bypass stenoses were followed prospectively by ultrasound Duplex scanning and ankle blood pressure measurements. During a median follow-up of 8 (range 0-22) months 18 (43%) (95% confidence limits 28-59%) bypasses thrombosed and 6 (14%) (95% confidence limits 5-29%) patients were amputated. Bypass patency was lower in 12 patients with stenoses associated with reduction in ankle brachial index (ABI) exceeding 0.15 than in 30 patients with no or only marginal reduction in ABI (12 month patency 33% vs. 68%, p = 0.005). Among the 30 patients without distal pressure reduction, stenoses identified within 3 months from surgery were associated with an increased risk of thrombosis as compared to stenoses identified at a later stage (12 month patency 51% vs. 92%, p = 0.03). Time interval from surgery to stenosis detection seems to be an independent parameter influencing outcome in patients with vein bypass stenoses.

The importance of routine surveillance of distal bypass grafts with duplex scanning: A study of 379 reversed vein grafts

To assess the utility of routine duplex surveillance, 379 infrainguinal reversed vein grafts performed at two independent teaching hospitals were prospectively entered into a surveillance protocol from March 1986 through August 1989. An average of 3.2 postoperative duplex graft flow velocity (GFV) measurements per graft was obtained during a mean follow-up interval of 21 12 months. Only 2.1% of 280 grafts with GFV measurements greater than 45 cm/sec failed within 6 months of a normal surveillance examination. GFV measurements less than 45 cm/sec in 99 grafts led to arteriography in 75 grafts, identifying 50 stenotic lesions in 48 bypasses (12.6% of series). Inflow lesions were present in 5%, outflow stenoses in 2%, and intrinsic graft stenoses in only 6% of bypasses. Only 29% of grafts identified as failing by duplex scan were associated with a reduction in ankle-brachial index of greater than 0.15. Secondary reconstructions were performed in 48 grafts based on detection of a reduced GFV measurement; all such reconstructions are patent after a mean follow-up of 5 months. Duplex surveillance is more reliable in identification of failing vein grafts than is determination of ankle-brachial index.