Ankle-brachial Index Categories Research Articles

Noncompressible Arteries Correlate With Increased Cardiovascular Mortality at 2 Years

The ankle-brachial index (ABI) is a useful screening tool for the detection of peripheral vascular disease (PVD). Using ABI measurements, patients can be stratified into different severities of arterial occlusive disease. Four hundred forty-four Veterans Health Administration Medical Center patients were referred for PVD between 2004 and 2005. Of those, 231 patients had an ABI ≤0.90 or >1.2 with known treatment and follow-up obtained from electronic medical records. These individuals had bilateral ABI measurements and were observed for a median of 23months (range, 4.0-60.0months). Patients were divided into 4 ABI categories: severe (ABI≤0.30; n = 62), moderate (ABI 0.30-≤0.60; n = 138), mild (ABI 0.60-≤0.90; n = 89), normal (ABI 0.90-≤1.2; n = 86), and noncompressible (ABI>1.2; n = 69). Mortality from cardiovascular disease in the severe, moderate, mild, normal, and noncompressible groups was 4.8%, 8.0%, 10.1%, 0%, and 21.7%, respectively, at the mean follow-up of 2years. For all-cause mortality, the overall percent for each group respectively was 32.3%, 31.9%, 31.5%, 14%, and 42% (P = 0.003). To our surprise, ABIs<0.9 did not show a linear correlation with 2-year survival. However, an ABI >1.2, indicating noncompressible arteries, correlated significantly with higher rates of mortality at a mean follow-up of 2years (33.3%). Cardiovascular disease and amputation were also significantly higher in those with noncompressible arteries than in the other groups. ABI is a noninvasive, inexpensive test that provides valuable information on a patient's risk of death. We recommend that patients with noncompressible vessels undergo systemic cardiovascular work-up, including coronary and carotid artery evaluation.

Predictive value of ankle-brachial index to all-cause mortality and cardiovascular mortality in Chinese patients with chronic kidney disease

To investigate the predictive value of ankle-brachial index (ABI) for all-cause mortality and cardiovascular mortality in Chinese patients with chronic kidney disease (CKD). 1563 CKD patients were enrolled in the cohort and were followed up for about 3 years in China. CKD was defined as an eGFR less than 60 ml/min/1.73m(2). 573 participants were diagnosed with PAD using ABI <= 0.90. Their average age was 73.4 ±8.2 years. During a median follow-up of 38 months, there were 1353 CKD patients with complete data. A total of 313 patients (161 with and 152 without PAD) died during follow-up. 184 deaths (99 with and 85 without PAD) were caused by cardiovascular disease (CVD). All-cause and CVD mortality of CKD patients with PAD was increased 2.2-fold and 2.4-fold compared with CKD patients without PAD. The hazard ratio (HR) of PAD for all-cause and CVD mortality was 2.15 (95 % CI: 1.66 - 2.79) and 2.51 (95 % CI: 1.80 - 3.50) respectively. Mortality of CKD patients significantly increased with decreasing ABI. That of CKD patients with ABI <= 0.4 was the highest (42.9 % and 28.6 %, respectively) in different ABI categories. Relative risks of all-cause and CVD mortality of CKD patients with ABI <= 0.4 were increased 3.479-fold (95 % CI: 2.076 - 5.830) and 4.960-fold (95 % CI: 2.644 - 9.302) respectively compared with those of patients with ABI > 1.0 and <= 1.4. Special models to evaluate the predictive value of ABI to mortality of CKD patients suggested that addition of ABI significantly increased the predictive value of the model for 3-year mortality compared with a model including conventional risk factors alone. Low ankle-brachial index can predict increased mortality of chronic kidney disease patients. Addition of ankle-brachial index can significantly improve the prediction of 3-year mortality compared with conventional risk factors alone.

Influencia de la elevación del índice tobillo/brazo en el riesgo cardiovascular y supervivencia en varones adultos sin enfermedad arterial periférica

ObjectiveThe clinical significance of an increased ankle/brachial index (ABI) and its association with risk factors and cardiovascular disease has been subject of controversy. Our objective was to evaluate the association between an increased baseline ABI with the risk of cardiovascular mortality (CVM), total mortality (TM) and increased major coronary events (MCE) at 5 years of follow-up in a Mediterranean population. Subjects and methodsA prospective survey was conducted on 614 men between 55 and 74 years-old with no peripheral arterial disease and representative of an urban district near Barcelona (Spain). Baseline cardiovascular risk factors and categorised ABI were recorded. ABI categories were: 0.9-1.24 (A), 1.25-1.34 (B), ≥1.35 (C). MCE, mortality and their cause were evaluated during 5-years of follow-up. ResultsThe distribution of subjects according to their ABI was: A=441 (71.8%), B=113 (18.4%) and C=60 (9.7%). The B and C group subjects had a higher prevalence of hypertension (P<.01), higher cholesterol plasma levels (P=.04) and smokers (P<0.01) compared to the normal ABI group (A), with the other risk factors assessed being similar. At 5-year follow-up (mean 65 months), and after adjustment for confounding factors, CVM and TM risk for B subjects were 1.33 (0.48-3.6, P=.57) and 1.07 (0.55-2.08, P=.83) respectively, compared to the normal ABI group (A). For C subjects they were 0.53 (0.07-4.02, P=.54) and 0.79 (0.28-2.22, P=.66). There were no significant differences in MCE risk between ABI groups (P=.07 for B and P=0.97 for C, related to A). ConclusionsIn our study, an increased ABI is associated with a higher prevalence of some risk factors; however this haemodynamic finding does not seem to be associated with an additional independent risk of MCE or mortality in our setting.

Peripheral Arterial Disease as an Independent Predictor for Excess Stroke Morbidity and Mortality in Primary-Care Patients: 5-Year Results of the getABI Study

Background:There is controversial evidence with regard to the significance of peripheral arterial disease (PAD) as an indicator for future stroke risk. We aimed to quantify the risk increase for mortality and morbidity associated with PAD. Methods:In an open, prospective, noninterventional cohort study in the primary care setting, a total of 6,880 unselected patients ≧65 years were categorized according to the presence or absence of PAD and followed up for vascular events or deaths over 5 years. PAD was defined as ankle-brachial index (ABI) <0.9 or history of previous peripheral revascularization and/or limb amputation and/or intermittent claudication. Associations between known cardiovascular risk factors including PAD and cerebrovascular mortality/events were analyzed in a multivariate Cox regression model. Results:During the 5-year follow-up [29,915 patient-years (PY)], 183 patients had a stroke (incidence per 1,000 PY: 6.1 cases). In patients with PAD (n = 1,429) compared to those without PAD (n = 5,392), the incidence of all stroke types standardized per 1,000 PY, with the exception of hemorrhagic stroke, was about doubled (for fatal stroke tripled). The corresponding adjusted hazard ratios were 1.6 (95% confidence interval, CI, 1.1–2.2) for total stroke, 1.7 (95% CI 1.2–2.5) for ischemic stroke, 0.7 (95% CI 0.2–2.2) for hemorrhagic stroke, 2.5 (95% CI 1.2–5.2) for fatal stroke and 1.4 (95% CI 0.9–2.1) for nonfatal stroke. Lower ABI categories were associated with higher stroke rates. Besides high age, previous stroke and diabetes mellitus, PAD was a significant independent predictor for ischemic stroke. Conclusions:The risk of stroke is substantially increased in PAD patients, and PAD is a strong independent predictor for stroke.

Association of Chronic Kidney Disease With the Spectrum of Ankle Brachial Index: The CHS (Cardiovascular Health Study)

This study sought to determine the association of chronic kidney disease (CKD) with high ankle brachial index (ABI) measurement and to compare its strength with that of CKD with a low ABI. CKD is an important risk factor for cardiovascular disease (CVD) events. A high ABI, a marker of lower extremity arterial stiffness, is associated with CVD events and mortality. The association between CKD and high ABI is unknown. The CHS (Cardiovascular Health Study) enrolled community-living people >65 years of age and measured kidney function and ABI. Glomerular filtration rate (GFR) was estimated using equations that incorporated either cystatin C or creatinine, and CKD was defined by estimated GFR <60 ml/min/1.73 m(2). The ABI was categorized as low (<0.90), low-normal (0.90 to 1.09), normal (1.10 to 1.40), and high (>1.40 or incompressible). Multinomial logistic regression was used to evaluate the associations of CKD with ABI categories. Among 4,513 participants, 23% had CKD, 13% had a low ABI, and 3% had a high ABI. In models adjusted for age, sex, race, hypertension, diabetes, smoking, body mass index, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, and C-reactive protein, cystatin C-based CKD was associated with both low ABI (relative risk [RR]: 2.0; 95% confidence interval [CI]: 1.6 to 2.5; p <0.001) and high ABI (RR: 1.6; 95% CI: 1.0 to 2.3; p = 0.03). Results were similar when CKD was defined by creatinine. CKD is associated with both the high and the low extremes of ABI in community-living older people. Future studies should evaluate whether arterial stiffness is an important mechanism leading to CVD in people with CKD.

Relationship of ankle–brachial index with all-cause mortality and cardiovascular mortality after a 3-year follow-up: the China ankle–brachial index cohort study

This study aimed to investigate the relationship of ankle-brachial index (ABI) with all-cause mortality and cardiovascular (CV) mortality in Chinese inpatients after 3 years of follow-up. All the participants were inpatients at high risk of atherosclerosis and enrolled from July to November 2004. A total of 3210 patients were followed up until an end point was reached or until February 2008. The mean follow-up time was 37.65+/-1.54 months. Patients with ABI <or=0.4 were significantly older than other ABI categories (P<0.001) at baseline. The all-cause and CV disease (CVD) mortality were highest (37.7 and 27.5%, respectively) after a 3-year follow-up in patients with ABI <or=0.4. There was a significant increasing tendency in mortality with decreasing ABI levels (P<0.001). The Kaplan-Meier curves of survival showed a decreasing survival rate with the ABI decreasing, not only for all-cause mortality but also for CVD mortality (P<0.001). Adjusted for other risk factors, patients with ABI <or=0.4 were 3.105 times (95% CI 1.936-4.979) as likely to die as those with ABI in the range of 1.00-1.4; patients with ABI <or=0.4 were about five times (95% CI 2.740-8.388) as likely to die of CVD as those with ABI in the range of 1.00-1.4. Even patients with ABI in the range of 0.41-0.90 were more than 1.5 times as likely to die (relative risk=1.534, 95% CI 1.199-1.962), or die of CVD (relative risk=2.031, 95% CI 1.479-2.789) as those with ABI in the range of 1.00-1.4. Low ABI is related to a higher all-cause and CV mortality compared with normal ABI. ABI as a marker of atherosclerosis should be routinely evaluated to assess the risk of CV mortality in Chinese patients.

Associations of Borderline and Low Normal Ankle-Brachial Index Values With Functional Decline at 5-Year Follow-Up: The WALCS (Walking and Leg Circulation Study)

We studied associations of borderline and low normal ankle-brachial index (ABI) values with functional decline over a 5-year follow-up.The associations of borderline and low normal ABI with functional decline are unknown.The 666 participants included 412 with peripheral arterial disease (PAD). Participants were categorized as follows: severe PAD (ABI <0.50), moderate PAD (ABI 0.50 to 0.69), mild PAD (ABI 0.70 to 0.89), borderline ABI (0.90 to 0.99), low normal ABI (1.00 to 1.09), and normal ABI (ABI 1.10 to 1.30). Outcomes were assessed annually for 5 years. Mobility loss was defined as loss of the ability to walk one-quarter mile or walk up and down 1 flight of stairs without assistance among participants without baseline mobility impairment. Becoming unable to walk for 6 min continuously was defined as stopping during the 6-min walk at follow-up among those who walked for 6 min continuously at baseline. Results were adjusted for age, sex, race, comorbidities, and other confounders.Hazard ratios (HRs) for mobility loss according to ABI category were as follows: severe PAD, HR: 4.16 (95% confidence interval [CI]: 1.58 to 10.92); moderate PAD, HR: 3.82 (95% CI: 1.66 to 8.81); mild PAD, HR: 3.22 (95% CI: 1.43 to 7.21); borderline ABI, HR: 3.07 (95% CI: 1.21 to 7.84); and low normal ABI, HR: 2.61 (95% CI: 1.08 to 6.32; p trend = 0.0018). Similar associations were observed for becoming unable to walk for 6 min continuously (p trend < 0.0001).At 5-year follow-up, persons with borderline ABI values have a higher incidence of mobility loss and becoming unable to walk for 6 min continuously compared with persons who have a normal baseline ABI. A low normal ABI is associated with an increased incidence of mobility loss compared with persons who have a normal ABI.

Systemic Risk Score Evaluation in Ischemic Stroke Patients (SCALA)

Stratification of patients with transient ischemic attack (TIA) or ischemic stroke (IS) by risk of recurrent stroke can contribute to optimized secondary prevention. We therefore aimed to assess cardiovascular risk factor profiles of consecutive patients hospitalized with TIA/IS to stratify the risk of recurrent stroke according to the Essen Stroke Risk Score (ESRS) and of future cardiovascular events according to the ankle brachial index (ABI) as a marker of generalized atherosclerosis In this cross-sectional observational study, 85 neurological stroke units throughout Germany documented cardiovascular risk factor profiles of 10 consecutive TIA/IS patients on standardized questionnaires. Screening for PAD was done with Doppler ultrasonography to calculate the ABI. A total of 852 patients (57% men) with a mean age of 67+/-12.4 years were included of whom 82.9 % had IS. The median National Institutes of Health stroke sum score was 4 (TIA: 1). Arterial hypertension was reported in 71%, diabetes mellitus in 26%, clinical PAD in 10%, and an ABI < or = 0.9 in 51%. An ESRS > or = 3 was observed in 58%, which in two previous retrospective analyses corresponded to a recurrent stroke risk of > or = 4%/year. The correlation between the ESRS and the ABI was low (r = 0.21). A high proportion of patients had asymptomatic atherosclerotic disease and a considerable risk of recurrent stroke according to the ABI and ESRS category. The prognostic accuracy as well as the potential benefit of various risk stratification scores in secondary stroke prevention require validation in a larger prospective study.

Metabolisches Syndrom und periphere arterielle Verschlusskrankeit als Indikatoren für erhöhtes kardiovaskuläres Risiko

The usefulness of the metabolic syndrome (MetS) or a low ankle brachial index (ABI), respectively, to identify patients with high risk for cardiovascular events has repeatedly been postulated. However, robust data on the prevalence and prognosis of such patients are missing in the primary care setting. In the prospective, non-interventional "German epidemiological trial on Ankle Brachial Index (getABI) at total of 6880 unselected patients > or = 65 years were observed by their General Practitioners over 3 years. Death and cardiovascular events were recorded. The definition of MetS was similar to the one of NCEP ATP III (National Cholesterol Education Program--Adult Treatment Panel III). ABI (ratio of the systolic blood pressures measured at the distal part of the calf and at the upper arm) was measured with Doppler sonography. Peripheral arterial disease (PAD) was defined as ABI <0.9 or peripheral revascularization/amputation owing to PAD. Survival analyses were conducted with a Cox proportional hazard model. Hazard rate ratios (HRR, 95 % confidence intervals, CI) were multvariate adjusted. The observation time for the total cohort was more than 20,000 patient years (PY). Cardiovascular mortality in patients with MetS (n = 3040, 44 %) compared to patients without MetS (n = 3795; 55 %) was doubled (8.5 vs. 4.0 per 1,000 PY; HRR: 2.0; CI 1.3 - 2.9). Concomitant presence of MetS and PAD (n = 651; 9.5 %) increased the mortality risk compared to patients without both conditions (n = 3194; 46.4 %) drastically (21.1 vs. 3.0 per 1000 PY; HRR: 5.7; CI: 3.5 - 9.4). Similar significant risk increases also were noted for all-cause mortality or a combined endpoint of mortality and vascular morbidity. Further, in lower ABI categories cardiovascular event rates increased. Patients with MetS carry a substantially increased risk of premature death, especially cardiovascular death, and therefore require intensive treatment of their risk factors. This holds especially true if concomitant PAD is present.

Association Between the Ankle-Brachial Index and Future Coronary Calcium (The Rancho Bernardo Study)

This study investigated whether the ankle-brachial index (ABI) is associated with coronary artery calcium (CAC) in a cohort of men and women who were free of clinical coronary heart disease. CAC was assessed by electron beam computed tomography in 279 community-based subjects who also had ABI measurements 7 years previously. Patients' mean age was 65.8 years and 51.3% were women. Thirty-three patients (11.8%) had an ABI < 1.0, 11 (3.9%) had an ABI < 0.9, and 4 (1.4%) had an ABI < 0.8. Prevalences of any CAC were 70% for women and 95% for men. In men and women, there was a U-shaped relation between CAC and ABI category, with the lowest CAC score being in the interval from 1.0 to 1.09. On multivariable analysis, women whose ABI was < 1.0 had a 2.7-fold higher risk (p = 0.03) for increasing amounts of CAC. Men whose ABI was below this same cutpoint had a similar but nonsignificant increase in risk (odds ratio 2.1, p = 0.1). In conclusion, ABI was significantly associated with the presence and extent of future CAC measured 7 years later.

Low Ankle-Brachial Index Associated With Rise in Creatinine Level Over Time

A low ankle-brachial index (ABI) predicts risk of cardiovascular death, myocardial infarction, peripheral arterial disease events, and stroke. However, it is unknown whether a low ABI also predicts a decline in renal function. We examined the association between ABI and change in serum creatinine level over time among 13 655 participants in the Atherosclerosis Risk in Communities (ARIC) study who underwent serum creatinine and ABI measurement at baseline and also underwent serum creatinine measurement 3 years later at the second study visit. The study outcome was a 50% rise in serum creatinine level from baseline to the second study visit. Overall, 0.48% of participants with an ABI of 1 or higher, 0.9% of participants with an ABI between 0.9 and 0.99, and 2.16% of participants with an ABI lower than 0.9 experienced a 50% or greater increase in serum creatinine level. In multivariate analysis, participants with an ABI lower than 0.9 were still more than twice as likely as those in the referent category (ABI > or = 1) to experience an increase in serum creatinine level (odds ratio 2.5; 95% confidence interval, 1.1-5.7) (P = .04), and a linear trend in the incidence of worsening renal function was noted across ABI categories (P = .02). Analyses excluding participants with renal insufficiency, diabetes, and hypertension at baseline all produced similar results. In addition to known associations of the ABI with stroke, myocardial infarction, peripheral arterial disease events, and cardiovascular death, a low ABI also predicts an increase in serum creatinine level over time.

Impaired lung function and subclinical atherosclerosis: The ARIC Study

An association between reduced pulmonary function and increased risk of atherosclerotic vascular events has been reported. The mechanisms underlying this association are unknown, but are unlikely to be entirely due to smoking given the presence of the association among non-smokers. Few studies have examined the cross-sectional association between subclinical atherosclerosis and pulmonary function. In 14,000 adults in the ARIC Study, we examined the cross-sectional relationship between lung function, measured by the forced expiratory volume at 1 s (FEV 1), and three markers of subclinical atherosclerosis: ankle–brachial index (ABI), carotid intimal–medial thickness (IMT), and presence of carotid plaques. Mean FEV 1 was computed by ABI category, IMT category, or plaque status, in the full cohort and after stratification by smoking status, adjusted for age, gender, race, study center, height, height-squared, smoking, and pack years. Decreased FEV 1 was associated with decreased ABI and increased IMT in the full cohort and in each smoking group. Further adjustment for CVD risk factors did not alter the ABI association, but attenuated the IMT association, eliminating it in never smokers. Plaque was not associated with FEV 1. These findings suggest a complex relationship between FEV 1 and atherosclerotic vascular disease that invites further study.