Prognostic Significance of Declining Ankle-brachial Index Values in Patients with Suspected or Known Peripheral Arterial Disease

Evaluation of Lower Extremity Calcium Score as a Measure of Peripheral Arterial Disease Burden and Amputation Risk

BACKGROUND

The ankle-brachial pressure index (ABI) and toe-brachial pressure index (TBI) are commonly used diagnostic tools for peripheral artery disease (PAD) that are unreliable in the presence of calcified vessels. In this study, we aimed to demonstrate the utility of the lower extremity calcium score (LECS) in addition to ABI and TBI in measuring disease burden and predicting the risk of amputation in patients with PAD.

METHODS

Patients who were evaluated in the vascular surgery clinic at Emory University for PAD and who underwent noncontrast computed tomography of the aorta and lower extremities were included in the study. Aortoiliac, femoral-popliteal, and tibial calcium scores were measured using the Agatston method. ABI and TBI that were obtained within 6 months of the computed tomography scan were noted and divided into categories of PAD severity. Associations between ABI, TBI, and LECS of each anatomic segment were evaluated. Univariate and multivariate ordinal regression analyses were performed to predict the outcome of amputation. Receiver operating characteristic analysis was performed to compare LECS with other variables in its ability to predict amputation.

RESULTS

Fifty patients included in the study cohort were divided into LECS quartiles, with 12-13 patients in each quartile. The highest quartile tended to be older (P = 0.016), had a higher percentage of diabetics (P = 0.034), and had a higher frequency of major amputations (P = 0.004) compared to the other quartiles. Patients in the highest quartile of tibial calcium score were more likely to have stage 3 chronic kidney disease (CKD) or greater (P = 0.011) and also had a higher frequency of amputation (P < 0.005) and mortality (P = 0.041). We found no significant association between each anatomic LECS and ABI/TBI categories. On univariate analysis, CKD (Odds Ratio [OR] 12.92 (95% CI 2.01 to 82.83), P = 0.007), diabetes mellitus (OR 5.47 (95% CI 1.27 to 23.64), P = 0.023), tibial calcium score (OR 6.62 (95% CI 1.79 to 24.54), P = 0.005), and total bilateral calcium score (OR 6.32 (95% CI 1.18 to 33.78), P = 0.031) were associated with increased risk of amputation. On multivariate stepwise ordinal regression, TBI and tibial calcium score were identified as important predictors of amputation, with hyperlipidemia and CKD increasing the overall prediction of the model. On Receiver operating characteristic analysis, the addition of the tibial calcium score (area under the curve 0.94, standard error 0.048) significantly improved the prediction of amputation compared to hyperlipidemia, CKD, and TBI alone (area under the curve 0.82, standard error 0.071, P = 0.022).

CONCLUSIONS

The addition of tibial calcium score to other known PAD risk factors may improve the prediction of amputation in patients with PAD.

Infrared Thermography as a Diagnostic Tool for Peripheral Artery Disease

OBJECTIVE

The prevalence of peripheral arterial disease (PAD) is increasing worldwide. The ankle-brachial index (ABI) is considered the criterion standard of noninvasive screening, but it does have limitations. The present study aimed to clarify the clinical diagnostic potential of infrared thermography (IRT) compared with conventional noninvasive measurements for PAD.

METHODS

Patients were divided into two groups: the healthy control group (n = 93) and the PAD group (n = 164). Control participants had an ABI 0.9 to 1.4 and no former PAD diagnosis. The PAD group was divided into three subgroups based on ABI classifications and two subgroups based on toe pressure measurements. Investigators performed IRT using a standardized protocol with temperature measurements at five different foot sites.

MAIN RESULTS

Differences in skin temperatures between feet were greater (P < .001) in the PAD group than in healthy controls. In general, mean foot temperatures were lower in the PAD group than in controls but did not differ significantly among PAD subgroups based on ABI classifications or toe pressure measurements.

CONCLUSIONS

Infrared thermography effectively distinguished temperature differences between feet and thus might be diagnostically useful. However, because normal skin surface temperature varies among individuals, IRT alone cannot be recommended for evaluating PAD. However, it does have potential to provide additional information about circulation, subclinical infections, and the severity of vascular disease.

Ankle-Brachial Index for Risk Stratification in Patients With Symptomatic Peripheral Artery Disease With and Without Prior Lower Extremity Revascularization: Observations From the EUCLID Trial

[Figure: see text].

Change in ankle-brachial index and mortality among individuals with chronic kidney disease: findings from the Chronic Renal Insufficiency Cohort Study

BACKGROUND

Patients with chronic kidney disease (CKD) have an increased risk of peripheral arterial disease (PAD). The ankle-brachial index (ABI), a noninvasive measure of PAD, is a predictor of adverse events among individuals with CKD. In general populations, changes in ABI have been associated with mortality, but this association is not well understood among patients with CKD.

METHODS

We conducted a prospective study of 2920 participants in the Chronic Renal Insufficiency Cohort Study without lower extremity revascularization or amputation at baseline and with at least one follow-up ABI measurement (taken at annual visits) during the first 4 years of follow-up. The ABI was obtained by the standard protocol.

RESULTS

In Cox proportional hazard regression analyses, we found a U-shaped association of average annual change in ABI with all-cause mortality. After adjusting for baseline ABI and other covariates, compared with participants with an average annual change in ABI of 0-<0.02, individuals with an average annual change in ABI <-0.04 or ≥0.04 had multivariable-adjusted hazard ratios (HRs) of 1.81 [95% confidence interval (CI) 1.34-2.44) and 1.42 (95% CI 1.12-1.82) for all-cause mortality, respectively. Compared with the cumulative average ABI of 1.0-<1.4, multivariable-adjusted HRs for those with a cumulative average ABI of <0.9, 0.9-<1.0 and ≥1.4 were 1.93 (95% CI 1.42-2.61), 1.20 (0.90-1.62) and 1.31 (0.94-1.82), respectively.

CONCLUSIONS

This study indicates both larger decreases and increases in average annual changes in ABI (>0.04/year) were associated with higher mortality risk. Monitoring changes in ABI over time may facilitate risk stratification for mortality among individuals with CKD.

Rehabilitative Exercise Reduced the Impact of Peripheral Artery Disease on Vascular Outcomes in Elderly Patients with Claudication: A Three-Year Single Center Retrospective Study

The study retrospectively evaluated the association between rehabilitative outcomes and risk of peripheral revascularizations in elderly peripheral artery disease (PAD) patients with claudication. Eight-hundred thirty-five patients were enrolled. Ankle-brachial index (ABI) and maximal walking speed (S_max) were measured at baseline and at discharge from a structured home-based rehabilitation program. For the analysis, patients were divided according to a baseline ABI value (severe: ≤0.5; moderate: ≥0.5) and according to hemodynamic or functional rehabilitative response (responder: ABI ≥ 0.10 and/or S_max > 0.5 km/h). Three-year outcomes were collected from the regional registry. According to the inclusion criteria (age 60–80, ABI < 0.80; program completion) 457 patients, 146 severe and 311 moderate, were studied. The whole population showed significant functional and hemodynamic improvements at discharge, with 56 revascularizations and 69 deaths at follow-up. Compared to the moderate group, the severe group showed a higher rate of revascularizations (17% vs. 10%, p < 0.001) and deaths (29% and 8%, respectively; p < 0.001). However, patients with severe PAD who were ABI responders after rehabilitation showed less revascularizations than non-responders (13% vs. 21%; hazard ratio (HR): 0.52) and were not different from patients with moderate disease (9%). Superimposable rates were observed for S_max responders (13% vs. 21%; HR: 0.55; moderate 10%). In conclusion, elderly patients with severe PAD empowered by better rehabilitation outcomes showed lower rates of peripheral revascularizations and deaths that were comparable to patients with moderate PAD.

Ankle brachial index is equally predictive of exercise-induced limb ischemia in diabetic and non-diabetic patients with walking limitation

BACKGROUND

In diabetic patients, arterial stiffness may impair compressibility of vessels and result in higher ankle to brachial index (ABI) than in non-diabetic subjects.

METHODS

We studied 1972 non-diabetic and 601 diabetic patients, with suspected peripheral artery disease, Exercise transcutaneous oxygen pressure (Ex-tcpO2), expressed in DROP index (limb tcpO2 change minus chest tcpO2 change), is insensitive to arterial stiffness and can estimate exercise-induced regional blood flow impairment (RBFI). A minimal DROP <-15 mm Hg indicates the presence of RBFI (positive test). ABI was simplified to a category variable (ABIc) by rounding ABI to the closest first decimal.

RESULTS

In the ABIc range 0.4 to 1.1 linear regression for mean DROP values were: y = 34 x - 53; (R² = 0.211) and y = 33 x - 52; (R² = 0.186) in diabetic and Non-diabetic patients, respectively. Both Db and non-D patients showed a high proportion of positive Ex-tcpO2 tests for ABIc in the normal range (ABIc: 1.0 and over) from 27.1 to up to 58%. More than half of patients with borderline ABI (ABIc = 0.9) had RBFI during exercise. it was 65.6% in diabetic and 58.5% non-diabetic patients.

CONCLUSIONS

Resting ABI was not a better predictor of exercise-induced RBFI in non-Db than in Diabetic patients. Our results highlights the interest of still measuring resting-ABI in diabetic patients to argue for the vascular origin of exertional limb pain, but also of performing exercise tests in patients with walking impairment.

Exercise transcutaneous oximetry significantly modifies the diagnostic hypotheses and impacts scheduled investigations or treatments of patients with exertional limb pain

INTRODUCTION

In lower extremity peripheral artery disease (PAD), transcutaneous oximetry at exercise (Ex-TcpO2) has been largely validated in research practice, but evidence of routine practice in various vascular laboratories is missing. We hypothesized that Ex-TcPO2 would change the diagnosis hypotheses, investigations and treatments for patients referred for exertional limb pain.

MATERIAL & METHODS

A multicenter prospective trial was conducted in nine different referral centers. Investigators performed Ex-TcpO2 and recorded investigations and treatments already scheduled for the patient. We encoded referral physician's diagnostic hypothesis. Before Ex-TcpO2, vascular physicians were asked to give their diagnosis hypotheses. A minimal decrease from rest of oxygen pressure (DROP)<minus 15mmHg defined the presence of exercise-induced ischemia on the area of interest. After Ex-TcPO2, we recorded post-test diagnostic hypothesis and investigations and treatments to be cancelled or performed. We compared the diagnosis hypotheses, scheduled investigations and treatments, before and after the Ex-TcpO2.

RESULTS

We included 603 patients (485 males: 80.4%), aged 64.7±9.8years. The post-test diagnosis hypothesis differed in 266 patients (44.1%; p<0.0001) and in 96 patients (15.9%) from the pre-test hypothesis of referring and vascular physician, respectively. This led to the recommendation to cancel 27 scheduled investigations or treatments of a total cost of ~130,000 euros.

DISCUSSION

Ex-TcPO2 in patients with exertional limb pain is applicable in various vascular institutions, and significantly modifies the diagnostic hypotheses and impacts scheduled investigations or treatments of patients with exertional limb pain.

Additional functional outcomes after endovascular treatment for intermittent claudication

Background Endovascular treatment (EVT) for intermittent claudication (IC) is performed in selected patients where conservative treatment and training fail. Treatment outcomes reported in vascular registries (survival, limb-survival, and re-intervention rate) are inadequate for low-risk patients with IC. Additional measurements of blood flow reduction and functional impairment clarify the indication for treatment and facilitate outcome evaluation. Purpose To analyze the additional outcome information on peripheral arterial pressures and walking capacity obtained from a local registry of EVT. Material and Methods Patients with IC treated with endovascular technique (angioplasty or stent) were prospectively entered into a local registry in addition to the national registry (NORKAR), with information on arterial pressures (ankle brachial index [ABI]) and treadmill performance (maximum walking distance [MWD]). Results A total of 242 consecutive patients (41% women; median age, 70 years) receiving the first treatment between July 2010 and December 2012 were included, 61% with aorto-iliac lesions. After 3 months, mean ABI increased from 0.62 (0.59-0.64) to 0.85 (0.83-0.87). The median MWD increased from 160 m to 410 m. Sixty-two percent reached the test maximum of 10 min. The improvement in ABI and MWD persisted after 1 year. When preoperative ABI was moderately reduced (0.5-0.9), ABI was normal in 61% after 3 months and in 55% after 1 year. When preoperative ABI was low (<0.5), ABI was normal in 43% both after 3 months and 1 year. Conclusion ABI and walking capacity were important outcome variables and improved after EVT. ABI improvement was better for patients with moderately reduced preoperative ABI than with low ABI.

Detection of Subclinical Peripheral Artery Ischemia in Healthy Male Smokers by an Ankle-Brachial Index After Exercise: Sasayama Study

We investigated the relationship between smoking and the risk of nonnormal (≤0.99) ankle-brachial index (ABI) at rest and after ankle plantar flexion exercise in healthy male community dwellers. A cross-sectional study was performed including 228 Japanese men aged 40 to 64 years without a history of cardiovascular diseases. Participants were classified as never, ex-, and current smokers. We estimated the multivariate-adjusted odds ratios (ORs) for nonnormal ABI of ex- and current smokers in relation to never smokers after adjusting for age and other confounding factors. At rest, the prevalence of nonnormal ABI was not significantly different by smoking status. After exercise, the prevalence of nonnormal ABI increased from 1.8% to 11.5% in ex-smokers and from 3.8% to 17.0% in current smokers, while the prevalence did not significantly change in never smokers. The multivariate-adjusted OR for nonnormal ABI after ankle plantar flexion exercise, in relation to never smokers, was 3.85 (95% confidence interval [CI]: 0.79-18.9) for ex-smokers and 6.97 (95% CI: 1.32-36.7) for current smokers. Our results suggest that ABI after ankle plantar flexion exercise is useful for early detection of subclinical peripheral artery ischemia in male smokers without typical symptoms.

Earlobe Crease May Provide Predictive Information on Asymptomatic Peripheral Arterial Disease in Patients Clinically Free of Atherosclerotic Vascular Disease

The diagonal earlobe crease (ELC) has been regarded as a simple marker of atherosclerosis. There is no knowledge concerning the relation of ELC to the presence, extent, and severity of peripheral arterial disease (PAD). Patients (n = 253) without known atherosclerotic vascular disease and symptoms were enrolled consecutively. Ankle brachial index (ABI) was measured. Patients with ELC had lower ABI compared to those with no ELC (1.02 ± 0.12 vs 1.11 ± 0.08, P < .001). Multivariate analysis demonstrated ELC (95% confidence interval [CI]: 3.3-21.9; P: .001) and age (95% CI: 0.87-0.99; P = .02) as independent determinants of abnormal ABI. There was incremental increased frequency of ELC from normal ABI to significant PAD. We have shown for the first time a significant and independent association between presence of ELC and increased prevalence, extent, and severity of PAD in patients without overt atherosclerotic vascular disease.

Relation between aortic valve sclerosis and ankle-brachial index in participants clinically free of atherosclerotic vascular disease

Most patients with peripheral arterial disease (PAD) are asymptomatic and have similar vascular morbidity and mortality with patients with symptomatic PAD. Despite being a very highly prevalent disease, physicians underdiagnose and undertreat PAD. A total of 100 participants with aortic valve sclerosis (AVS) and 100 participants without AVS and age-, gender-, and cardiovascular risk factor-matched participants were enrolled. Ankle-brachial index (ABI) and AVS were evaluated by handheld Doppler device and echocardiography, respectively. There was significantly lower ABI in participants with AVS compared with those without AVS (1.04 ± 0.14 v 1.11 ± 0.07, P = .001). There was a negative correlation between ABI and AVS (r = -.29, P < .001). Linear regression analysis demonstrated an independent association between ABI and AVS (95% confidence interval [CI]: -0.91 to -0.27, P < .001) and β-blocker use (95% CI: -0.96 to -0.02, P: .04). Our findings confirm an association between AVS and PAD that may be attributed to shared vascular risk factors.

Change in ankle-brachial index over time and mortality in diabetics with proteinuria

Peripheral arterial disease is common in diabetic chronic kidney disease (CKD) and is characterized either by abnormally low or high ankle-brachial index (ABI). Whether low or high ABI carries similar prognostic value is unknown. The association of baseline ABI with all-cause mortality over 40 ± 21 months (mean ± SD) was ascertained in 167 proteinuric diabetics (age 57 ± 7 years; median urine protein-creatinine, 2.5 mg/mg). Association of change in ABI with all-cause mortality was determined in 75 subjects with normal ABI (0.9 - 1.3) at baseline. Among 167 participants, 41% had an abnormal ABI: < 0.9, 18%; and > 1.3 or non-compressible arteries, 23%. Only individuals with low ABI had a significantly higher risk for all-cause mortality (hazards ratio (95% confidence interval), HR: 2.23 (1.07, 4.65)). In subjects with normal ABI at baseline with follow-up measurement (n = 75), vascular disease worsened in 39% over 23 ± 6 months: 17% had either a decrease in ABI by ≥ 0.1 or a final ABI < 0.9, and 21% had a final ABI > 1.3 or noncompressible arteries. Only individuals who had a decrease in ABI over time had a significantly higher risk for death (adjusted HR, 7.41 (1.63, 33.65)). Peripheral arterial disease is not uncommon and progresses rapidly in individuals with diabetes and proteinuria. Low or declining ABI is a strong predictor of all-cause mortality. Routine measurement of ABI is a simple bed-side procedure that may permit easy risk-stratification in diabetic CKD patients.

Peripheral artery disease in peritoneal dialysis and hemodialysis patients: single-center retrospective study in Taiwan

Background

Peripheral artery disease (PAD) is a condition characterized by restricted blood flow to the extremities, and is especially common in the elderly. PAD increases the risk for mortality and morbidity in patients with end-stage renal disease (ESRD), especially those on hemodialysis (HD).

Methods

The records of 484 patients with end-stage renal disease who were on HD or peritoneal dialysis (PD) were reviewed. PAD was diagnosed based on the ankle-brachial pressure index (ABI). Demographic and clinical characteristics were analyzed.

Results

PAD had an overall prevalence of 18.2% and was significantly more common in HD patients (21.8%) than in PD patients (4.8%). Advanced age, diabetes mellitus, smoking, low parathyroid hormone level, elevated serum ferritin, elevated serum glucose, and low serum creatinine levels increased the risk for PAD. PAD was independently associated with advanced age, diabetes mellitus, duration of dialysis, low serum creatinine, and hyperlipidemia. PD patients had a significantly lower prevalence of PAD than HD patients, maybe due to their younger age and lower prevalence of diabetes mellitus in this present study.

Conclusions

The prevalence of PAD was greater in the HD group than the PD group. Most of the risk factors for PAD were specific to HD, and no analyzed factor was significantly associated with PAD in PD patients.

The relationship of peripheral arterial disease and metabolic syndrome prevalence in asymptomatic US adults 40 years and older: results from the National Health and Nutrition Examination Survey (1999-2004)

Peripheral arterial disease (PAD) is a subclinical marker of coronary artery disease and identifies asymptomatic individuals at high risk for cardiovascular disease (CVD) events. The metabolic syndrome (MetS) is a constellation of clinical factors that increases the risk of developing diabetes and CVD. The authors' objectives were to estimate the prevalence of MetS in patients with PAD and to determine the prevalence of PAD in the population of asymptomatic US adults 40 years and older with MetS. The authors analyzed data from 3 National Health and Nutrition Examination Surveys (NHANES, 1999-2004). Prevalence of MetS as defined by the Third Report of the Adult Treatment Panel criteria and prevalence of associated cardiac risk factors were determined in 5376 asymptomatic participants 40 years and older. Presence of PAD was defined as ankle-brachial index <0.9. Estimates were weighted with the sample weights accounting for the unequal selection probability of complex NHANES sampling and over sampling of selected population subgroups. Prevalence of PAD in asymptomatic US adults 40 years and older was 4.2%. PAD prevalence in persons with MetS was 7.0% compared with 3.3% in persons without MetS. A total of 38% of the population with PAD also had MetS. High rates of abdominal obesity, hypertension, hyperglycemia, and low high-density lipoprotein cholesterol are significant contributors to both MetS and PAD. Persons with MetS have twice the risk of having PAD. Of persons with PAD, almost 40% have MetS. The presence of either PAD or MetS should warrant screening for both conditions so that risk stratification and management of risk factors may be performed.

The role of ankle brachial index and carotid intima-media thickness in vascular risk stratification

PURPOSE OF REVIEW

To summarize recent findings on the role of ankle brachial index (ABI) and carotid intima-media thickness (cIMT) in vascular risk stratification.

RECENT FINDINGS

The combination of either ABI or cIMT with the Framingham risk score does not appear to improve risk stratification more than the Framingham risk score alone.

SUMMARY

ABI and cIMT are well studied markers of atherosclerotic burden. Considerable evidence shows that they both are independently associated with increased vascular morbidity and mortality. However, their value in identifying high-risk patients among those with low or intermediate estimated risk appears to be limited. Regarding cIMT, this might be because cIMT is mostly a marker of early atherosclerosis. On the contrary, peripheral arterial disease (i.e. ABI <0.9) develops mostly in patients who already have high estimated vascular risk (e.g. elderly smokers or diabetic patients). Nevertheless, ABI is inexpensive, can be performed quickly and has high validity and good reproducibility, in contrast to the technical equipment and expertise required for measuring cIMT. Accordingly, ABI should be measured in patients at risk for peripheral arterial disease but not in all intermediate-risk patients indiscriminately. Finally, it has not been evaluated whether adding ABI or cIMT to the Framingham risk equation to guide management decisions will prevent more events than the use of the Framingham risk equation alone. Before the wider implementation of ABI or cIMT for risk stratification, this critical question has to be answered.

Study on Unrecognized Peripheral Arterial Disease (PAD) by Ankle/Brachial Index and Arterial Comorbidity in Catania, Sicily, Italy

Peripheral arterial disease (PAD) is under diagnosed and early diagnosis decreases consequences. We screened unrecognized PAD focusing on arterial co-morbidities. In the 3412 subjects, screened from 10 general practices in the city of Catania (Sicily, Italy), ankle brachial index (ABI) measurements were performed. An ABI ≤0.9 was considered as valid in diagnosing PAD. ABI value ≤0.9 was found in 2.3%, and a significant rate of carotid stenosis was also found Echocardiographic markers left ventricular diameter (LVD) >55 mm, interventricular septum (IVS) >11 mm, left ventricular diastolic volume (LVDV) was found > 100 ml), and ejection fraction (EF) was <50% were found with high frequency in those with ABI ≤0.9. Unrecognized PAD is lower compared with other findings but our prevalence resulted higher than other prevalence previously found by other study performed in Italy. Unrecognized PAD shows significant arterial co-morbidities and the ABI is a useful method to screen asymptomatic PAD.

Endofibrosis in athletes: is a simple bedside exercise helpful or sufficient for the diagnosis?

OBJECTIVE

Ankle-to-brachial index (ABI) can be easily performed by all physicians. The Ruffier-Dickson (RD) test is an easy procedure to attain moderate exercise at the bedside for physicians who do not have an ergometer.

DESIGN

Retrospective analysis.

SETTING

Tertiary care, institutional practice.

PATIENTS

Fifty-three asymptomatic athletes and 22 patients suffering from unilateral pain due to histologically proven exercise-induced arterial endofibrosis (EIAE).

INTERVENTION

Brachial and ankle systolic blood pressures were measured in the supine position on the suspected leg in EIAE or left leg in controls, at rest (rest) and at the first minute of the recovery from incremental maximal cycle ergometer exercise (maxCE) and Ruffier-Dickson (RD) exercise tests.

MAIN OUTCOME MEASURES

Comparison of ABI(rest), ABI(maxCE), and ABI(RD) in discriminating patients from normal subjects, using receiver operating characteristics (ROC) curves.

RESULTS

Area (+/-SE of area) of ROC curve was 0.76 +/- 0.06 for ABI(rest), 0.83 +/- 0.05 for ABI(RD) (nonsignificant from rest), and 0.99 +/- 0.01 for ABI(maxCE) (P < 0.01 from ABI(RD) and P < 0.001 from ABI(rest)). An ABI(maxCE) below 0.48 was 100% specific and 80% sensitive for EIAE. For the RD test, a 100% negative predictive value was only attained for postexercise ABI values higher than 0.92.

CONCLUSION

ABI after maximal cycle ergometer exercise is more accurate than ABI after an RD test to search for unilateral EIAE in athletes.

Brachial-ankle pulse wave velocity is associated with walking distance in patients referred for peripheral arterial disease evaluation

OBJECTIVE

Impaired functional capacity predicts morbidity and increased mortality in patients with PAD. We hypothesized that brachial-ankle pulse wave velocity (baPWV), a measure of arterial stiffness, is associated with functional capacity in patients undergoing noninvasive evaluation for peripheral arterial disease (PAD).

METHODS

We studied 114 patients (age 68+/-10 years) referred to Mayo Clinic's noninvasive vascular laboratory. Functional capacity was estimated in terms of distance walked in 5 min on a treadmill at a speed of 1.0-2.0 mph. Ankle-brachial index (ABI) was obtained with Doppler method before and 1 min after exercise. baPWV was estimated noninvasively using an oscillometric device. The association of baPWV with walking distance was assessed using accelerated failure time and Cox proportional-hazards models.

RESULTS

The mean baPWV was higher in patients who were unable to complete the walk test compared to those who successfully completed the test (P=0.008). Higher baPWV was associated with a lower walking distance after adjustment for heart rate, mean arterial pressure, and cardiovascular risk factors (P=0.017) and after additional adjustment for pulse pressure (P=0.034) and ABI (P=0.030). Higher baPWV was associated with failure to complete the treadmill walk test, after adjustment for heart rate, mean arterial pressure, and cardiovascular risk factors (P=0.025) and after additional adjustment for pulse pressure (P=0.041) and ABI (P=0.039).

CONCLUSION

Increased baPWV, a measure of arterial stiffness, is associated with impaired functional capacity in patients undergoing evaluation for PAD.

Epidemiology and diagnosis of peripheral arterial disease in patients with chronic kidney disease

Chronic kidney disease (CKD) and peripheral arterial disease (PAD) are common and frequently coexist. Among subjects with CKD, arterial disease may be due to atherosclerosis, medial arterial calcification (MAC), or both conditions concomitantly. It is important for clinicians to recognize both conditions because each identifies individuals at higher risk of cardiovascular disease events, and because the presence of MAC complicates interpretation of the ankle brachial index, the most commonly used diagnostic test for artherosclerotic PAD. To that end, we review the epidemiology and diagnosis of atherosclerotic PAD and medical arterial calcification in patients with CKD.

Physiological and functional impact of an unsupervised but supported exercise programme for claudicants

OBJECTIVES

To evaluate an unsupervised home-based exercise programme for physiological, functional, and quality of life impact in patients with symptomatic peripheral arterial disease.

DESIGN

Prospective cohort with exercise intervention.

MATERIALS

Human performance laboratory with non-invasive haemodynamic assessment facilities.

METHODS

Forty-seven patients with symptomatic peripheral arterial disease (mean age 67.6+/-7 years, 33 males) participated in an unsupervised home-based exercise programme. Heart rate (HR), ankle brachial blood pressure index (ABPI), leg blood flow (BF), and blood lactate were measured before and after a graded treadmill walk at baseline and after the 12-week exercise programme. Maximum walking distance (MWD) during the treadmill walk was measured at baseline and 12 weeks. Exercise compliance, functional parameters, and quality of life (VascuQoL) were assessed by questionnaire.

RESULTS

MWD, leg BF, and VascuQoL scores increased significantly, while resting HR, exercise HR, and end of walk rate-pressure-product (RPP) decreased significantly after 12 weeks. Exercise compliance was significantly correlated with increase in MWD (r=0.89, p<0.001) and QOL score improvement (r=0.61, p<0.001).

CONCLUSIONS

This supported but unsupervised exercise programme generated improvements in walking distance and leg blood flow without detectable increases in cardiorespiratory work. Exercise compliance is related to MWD and VascuQoL score in a dose-response manner.