Segmental arterial disease in the lower extremities: correlates of disease and relationship to mortality

Association of sex and cardiovascular risk factors with atherosclerosis distribution pattern in lower extremity peripheral artery disease

Objective

Atherosclerosis expression varies across not only coronary, cerebrovascular, and peripheral arteries but also within the peripheral vascular tree. The underlying pathomechanisms of distinct atherosclerosis phenotypes in lower extremity peripheral artery disease (PAD) is poorly understood. We investigated the association of cardiovascular risk factors (CVRFs) and atherosclerosis distribution in a targeted approach analyzing symptomatic patients with isolated anatomic phenotypes of PAD.

Methods

In a cross-sectional analysis of consecutive patients undergoing first-time endovascular recanalization for symptomatic PAD, data of patients with isolated anatomic phenotypes of either proximal (iliac) or distal (infrageniculate) atherosclerosis segregation were extracted. We performed a multivariable logistic regression model with backward elimination to investigate the association of proximal and distal PAD with CVRFs.

Results

Of the 637 patients (29% females) with endovascular recanalization, 351 (55%) had proximal and 286 (45%) had distal atherosclerosis. Female sex [odds ratio (OR) 0.33, 95% confidence interval (CI) 0.20-0.54, p = 0.01], active smoking (OR 0.16, 95% CI 0.09-0.28, p < 0.001), and former smoking (OR 0.33, 95% CI 0.20-0.57, p < 0.001) were associated with proximal disease. Diabetes mellitus (DM) (OR 3.25, 95% CI 1.93-5.46, p < 0.001), chronic kidney disease (CKD) (OR 1.18, 95% CI 1.08-1.28, p < 0.001), and older age (OR 1.31, 95% CI 1.06-1.61, p = 0.01) were associated with distal disease.

Conclusion

Female sex, particularly in the context of smoking, is associated with clinically relevant, proximal atherosclerosis expression. Our additional findings that distal atherosclerosis expression is associated with DM, CKD, and older age suggest that PAD has at least two distinct atherosclerotic phenotypes with sex-specific and individual susceptibility to atherogenic risk factors.

Red blood cell distribution width as a predictor of cardiovascular outcomes in extensive aortoiliac disease

BACKGROUND

Aortoiliac peripheral artery disease may lead to disabling lower limb claudication or to lower limb chronic threatening ischemia, which is associated with increased short and long-term morbi-mortality. The red blood cell distribution width-coefficient of variation (RDW-CV) has been able to predict outcomes in other atherosclerotic diseases, such as myocardial infarction and stroke. The main objective of this study was to assess the predictive ability of perioperative RDW-CV in accurately predicting short and long-term major adverse cardiovascular events (MACE) and all-cause mortality in patients submitted to aortoiliac revascularization due to extensive aortoiliac atherosclerotic disease.

METHODS

From 2013 to 2020, patients who underwent aortoiliac revascularization due to severe aortoiliac disease were included in a prospective cohort. Blood samples were taken preoperatively and the patient's demographics, comorbidities, and postoperative outcomes were assessed. A multivariate Cox regression model was used to adjust for confounding and assess the independent effect of these prognostic factors on the outcomes.

RESULTS

The study group included 107 patients. Median follow-up was 57 (95% CI: 34.4-69.6) months. Preoperative RDW-CV was increased in thirty-eight patients (35.5%). Increased RDW-CV was associated with congestive heart failure - adjusted odds ratio of 5.043 (95% CI: 1.436-17.717, P=0.012). It could predict long-term occurrence of MACE (adjusted hazard ratio [aHR] 1.065, 95% CI: 1.014-1.118, P=0.011), all-cause mortality (aHR=1.069, 95% CI: 1.014-1.126, P=0.013), acute heart failure (AHF) (aHR=1.569, 95% CI: 1.179-2.088, P=0.002), and stroke (aHR=1.343, 95% CI: 1.044-1.727, P=0.022).

CONCLUSIONS

RDW is a widely available and low-cost marker that was able to independently predict long-term AHF, stroke, MACE, and all-cause mortality in patients with extensive aortoiliac disease submitted to revascularization. This biomarker could help assess which patients would likely benefit from stricter follow-up in the long-term.

Lower Extremity Artery Disease as a Predictor of Coronary Artery Disease

Coronary artery disease (CAD) is an important determinant of long-term outcome in patients with lower extremity artery disease (LEAD). In this study we evaluated the CAD prevalence among LEAD patients and the association of LEAD lesions location with the CAD presence and severity. 203 patients with LEAD, referred for peripheral and simultaneous coronary angiography, were evaluated. LEAD and CAD were considered angiographically significant for stenosis higher than 50% of arterial lumen. More than two-thirds of LEAD patients had significant CAD, half of them having multi-vessel CAD and a quarter single CAD. Infrapoplitheal arterial lesions seemed to be the strongest predictor of CAD being associated with significant and multi-vessel CAD and also with the presence of left main (LM) lesions. Femoral artery lesions were highly associated with multi-vessel CAD, but there was no association with significant CAD and LM lesions. No association was found between iliac artery lesions and CAD.

Racial and Gender Disparity in Aortoiliac Disease Open Revascularization Procedures

BACKGROUND

The impact of race and gender on surgical outcomes has been studied in infrainguinal revascularization for peripheral arterial disease. The aim of this study is to explore how race and gender affect the outcomes of suprainguinal bypass (SIB) for aortoiliac occlusive disease.

MATERIALS AND METHODS

Patients who underwent SIB were identified from the procedure-targeted National Surgical Quality Improvement Program data set (2011-2016). Patients were stratified into four groups: nonblack males, black males (BM), nonblack females, and black females (BF). Primary outcomes were 30-d major adverse cardiac events, a composite of myocardial infarction, stroke, or death; postoperative bleeding requiring transfusion or intervention; major amputation and prolonged length of stay (>10 d). Predictors of outcomes were determined by multivariable logistic regression analysis.

RESULTS

About 5044 patients were identified. BM were younger, more likely to be smokers, less likely to be on antiplatelet drug or statin, and to receive elective SIB (all P ≤ 0.01). BFs were more likely to be diabetic and functionally dependent (all P ≤ 0.02). Major adverse cardiac events were not significantly different among all groups. BM had a threefold higher risk of amputation (adjusted odds ratio [OR] [95% confidence interval (95% CI)], 3.10 [1.50-6.43]; P < 0.002). Female gender was associated with bleeding in both races, that association was more drastic in BF (OR [95% CI], 2.43 [1.63-3.60]; P < 0.0001), whereas nonblack females (OR [95% CI], 1.46 [1.19-1.80]; P < 0.0001). BF had higher odds of prolonged length of stay (OR [95% CI]: 1.62 [1.08-2.42]; P < 0.019).

CONCLUSIONS

In this large retrospective study, we demonstrated the racial and gender disparity in SIB outcomes. BM had more than threefold increase in amputation risk as compared with nonblack males. Severe bleeding risk was more than doubled in BF. Race and gender consideration is warranted in risk assessment when patients are selected for aortoiliac disease revascularization, which in turn necessitate preoperative risk modification and optimization in addition to enhancing their access to primary preventive care measures.

Multivessel tibial revascularization does not improve outcomes in patients with critical limb ischemia

OBJECTIVE

Multivessel tibial revascularization for critical limb ischemia (CLI) remains controversial. The purpose of this study was to evaluate single vs multiple tibial vessel interventions in patients with multivessel tibial disease. We hypothesized that there would be no difference in amputation-free survival between the groups.

METHODS

Using the Vascular Quality Initiative registry, we reviewed patients undergoing lower extremity endovascular interventions involving the tibial arteries. Patients with CLI were included only if at least two tibial vessels were diseased and adequate perioperative data and clinical follow-up were available for review. The primary outcome was amputation-free survival.

RESULTS

There were 10,849 CLI patients with multivessel tibial disease evaluated from 2002 to 2017; 761 limbs had adequate data and follow-up available for review. Mean follow-up was 337 ± 62 days. Of these, 473 (62.1%) underwent successful single-vessel tibial intervention (group SV), whereas 288 (37.9%) underwent successful multivessel (two or more) intervention (group MV). Patients in group MV were younger (69.1 vs 73.2 years; P < .001), with higher tobacco use (29.5% vs 18.2%; P < .001). Group SV more commonly had concurrent femoral or popliteal inflow interventions (83.7% vs 78.1%; P = .05). Multivessel runoff on completion was significantly greater for group MV (99.9% vs 39.9%; P < .001). No differences were observed between group SV and group MV for major amputation (9.0% and 7.6%; P = .6), with similar amputation-free survival at 1 year (90.6% vs 92.9%; P = .372). In a multivariate Cox model, loss of patency was the only significant predictor of major amputation (hazard ratio, 5.36 [2.7-10.6]; P = .01). A subgroup analysis of 355 (46.6%) patients with tissue loss data showed that tissue loss before intervention was not predictive of future major amputation.

CONCLUSIONS

In the Vascular Quality Initiative registry, patients with CLI and occlusive disease involving multiple tibial vessels did not appear to have a limb salvage benefit from multiple tibial revascularization compared with single tibial revascularization.

The extent of atherosclerotic lesions in crural arteries predicts survival of patients with lower limb peripheral artery disease: A new classification of crural atherosclerosis

BACKGROUND AND AIMS

Several studies report correlation of ankle brachial index (ABI) values and mortality. However, no studies exist on the predictive value of anatomical distribution of atherosclerotic lesions and the extent of atherosclerosis at defined arterial segments on life expectancy. The aim of the present study was to evaluate the significance of both extent and localisation of atherosclerotic lesions to mid-term patient survival.

METHODS

Digital subtraction angiography (DSA) images of 887 consecutive patients admitted to the Department of Vascular Surgery at Turku University Hospital (Turku, Finland) were retrospectively analysed. Each angiography was classified according to the TASC II classification for aorto-iliac and femoro-popliteal segments, and a similar four-grade index was created for crural arteries. Patients were followed until 36-months post DSA.

RESULTS

During 36-month follow-up 295 (33%) deaths occurred. Death during follow-up was strongly associated with extensive crural disease, but not with extensive proximal disease (Crural Index III-IV, p = 0.044 and < 0.001, respectively). In a Cox regression analysis incorporating baseline variables, Crural Index IV and most severe atherosclerosis on crural vessels were the strongest predictors of poor prognosis (HR 2.20 95% CI 1.3-3.7, p = 0.003 and HR 2.45 95% CI 1.5-4.0, p < 0.001 respectively).

CONCLUSIONS

The extent of crural atherosclerosis is independently associated with poor mid term life expectancy. Therefore, a classification of the extent of crural atherosclerosis could serve as an indicator of mortality among PAD patients and aid in clinical decision making.

Management of Atherosclerotic Aortoiliac Occlusive Disease

Development of aortoiliac occlusive disease (AIOD) is associated with classic risk factors for atherosclerotic disease such as hyperlipidemia, hypertension, diabetes, or smoking. Risk factor modification, smoking cessation, and prevention of cardiovascular events remain the cornerstones of AIOD management. Symptom improvement and limb loss prevention are considered secondary goals of therapy. Continuous technological advances, new devices, as well as new revascularization techniques are constantly changing the landscape of AIOD management. Surgical interventions, which were considered a gold standard therapy for nearly 50 years, currently give way to newer and less invasive endovascular techniques.

Patterns of disease distribution of lower extremity peripheral arterial disease

Peripheral arterial disease (PAD) is a common manifestation of atherosclerosis that is associated with an increased risk of mortality and cardiovascular (CV) events. Peripheral arterial disease involves the arteries distal to the aortic bifurcation in a nonuniform manner. Studies have shown that symptoms and prognosis of patients with PAD vary according to the location and size of the affected artery. Several modalities have been used to identify the location of PAD, including noninvasive evaluations and invasive procedures. Peripheral arterial disease has a risk factor profile similar to that associated with coronary artery disease (ie, age, gender, diabetes, smoking, hypertension, and hyperlipidemia). Many studies have shown that the distribution, extent, and progression of PAD are influenced by CV risk factors but the findings are not consistent. Management strategies for PAD are different for proximal and distal PAD. The objective of this review is to discuss the patterns of diseases distribution in patients with PAD.

Disease location is associated with survival in patients with peripheral arterial disease

BACKGROUND

We investigated whether disease location influences survival in patients with peripheral arterial disease.

METHODS AND RESULTS

Patients (n = 12,731; mean age, 67.5 ± 12.7 years; 57.4% male) who underwent outpatient noninvasive lower extremity arterial evaluation were followed up for 5.9 ± 3.1 years for all-cause mortality. Peripheral arterial disease (n = 8930) was defined as a resting or postexercise ankle-brachial index (ABI) ≤ 0.90, and normal ABI (n = 3,801) was defined as a resting and postexercise ABI of 1.00 to 1.30. Presence or absence of disease at the proximal location or distal location was determined on the basis of Doppler signals in leg arteries; 42% had no PD or DD, 45% had proximal (14% postexercise PD only), 30% had distal disease, 17% had both proximal and distal disease, 28% had proximal only and 14% had distal only. We performed multivariable logistic regression to identify factors associated with disease location, and Cox proportional hazard regression to assess the respective effects of proximal or distal disease on survival. Older age, male sex, diabetes, heart failure, and critical limb ischemia were associated with distal disease, whereas female sex, smoking, hypertension, dyslipidemia, coronary heart disease, cerebrovascular disease, chronic obstructive pulmonary disease, and critical limb ischemia were associated with proximal disease. Over a mean follow-up of 5.9 ± 3.1 years, 3039 patients (23.9%) died. After adjustment for potential confounders, the hazard ratios (HRs) of death associated with PD only and DD only were 1.3 (1.3 to 1.4) and 1.5 (1.4 to 1.6), respectively. After additional adjustment for resting ABI, there was no significant association between proximal disease and death, whereas the association of distal disease with death remained significant (HR, 1.2; 95% CI, 1.1 to 1.3).

CONCLUSIONS

In patients with peripheral arterial disease, proximal and distal disease locations were associated with distinctive risk factor and comorbidity profiles. Distal disease was associated with worse survival even after adjustment for risk factors, comorbidities, and resting ABI.

Blood pressure regulation VIII: resistance vessel tone and implications for a pro-atherogenic conduit artery endothelial cell phenotype

Dysfunction of the endothelium is proposed as the primary initiator of atherosclerotic peripheral artery disease, which occurs mainly in medium- to large-sized conduit arteries of the lower extremities (e.g., iliac, femoral, popliteal arteries). In this review article, we propose the novel concept that conduit artery endothelial cell phenotype is determined, in part, by microvascular tone in skeletal muscle resistance arteries through both changes in arterial blood pressure as well as upstream conduit artery shear stress patterns. First, we summarize the literature supporting the involvement of sympathetic nerve activity (SNA) and nitric oxide (NO) in the modulation of microvascular tone and arterial blood pressure. We then focus on the role of elevated blood pressure and shear stress profiles in modulating conduit artery endothelial cell phenotype. Last, we discuss findings from classic and emerging studies indicating that increased vascular resistance, as it occurs in the context of increased SNA and/or reduced NO bioavailability, is associated with greater oscillatory shear stress (e.g., increased retrograde shear) in upstream conduit arteries. The ideas put forth in this review set the stage for a new paradigm concerning the mechanistic link between increased microvascular tone and development of conduit artery endothelial dysfunction and thus increased risk for peripheral artery disease. Indeed, a vast amount of evidence supports the notion that excessive blood pressure and oscillatory shear stress are potent pro-atherogenic signals to the endothelium.

Tibial artery calcification as a marker of amputation risk in patients with peripheral arterial disease

OBJECTIVES

The purpose of this study was to evaluate the relationship between calcification in tibial arteries, the degree of limb ischemia, and the near-term risk of amputation.

BACKGROUND

Determining the amputation risk in patients with peripheral arterial disease (PAD) remains difficult. Developing new measures to identify patients who are at high risk for amputation would allow for targeted interventions and focused trials aimed at limb preservation.

METHODS

Two hundred twenty-nine patients underwent evaluation by history, arterial Doppler, and multislice computed tomography of the lower extremities. We then explored the relationship between a tibial artery calcification (TAC), traditional risk factors for PAD, limb status at presentation, and near-term amputation risk.

RESULTS

Increased age and traditional atherosclerosis risk factors were associated with higher TAC scores. Patients with critical limb ischemia had the highest TAC scores, and increasing TAC scores were associated with worsening levels of limb ischemia in ordinal regression analysis. Receiver-operator characteristic analysis suggested that the TAC score predicted amputation better than the ankle-brachial index (ABI). Symptomatic patients with a TAC score greater than 400 had a significantly increased risk of amputation. In Cox regression analysis, there was a strong association between the TAC score and the risk of major amputation that remained after adjustment for traditional risk factors and the ABI.

CONCLUSIONS

In patients presenting with PAD, the TAC score is associated with the stage of disease and it identifies those who are at high risk for amputation better than traditional risk factors and an abnormal ABI.

Is chronic diabetic foot ulcer an indicator of cardiac disease?

OBJECTIVE

To evaluate presence and severity of cardiac disease in individuals with chronic diabetic foot ulcers using echocardiography.

METHOD

Eighty consecutive patients with chronic foot ulcers attending the multidisciplinary diabetes foot clinic at Helsingborg Hospital underwent clinical examination, toe blood pressure measurement and a standard echocardiographic examination.

RESULTS

Sixty-nine percent of the patients had a history of myocardial infarction and/or hypertension and/or heart failure; 78% had signs of left ventricular dysfunction and/or left ventricular hypertrophy and/or diastolic dysfunction; 76% of the patients without a history of cardiovascular disease had signs of cardiac dysfunction on echocardiography.

CONCLUSION

Cardiac dysfunction is a common occurrence present in patients with chronic diabetic foot ulcers, even in those without known cardiac disease or hypertension. Echocardiography may be recommended as a screening procedure in the management of diabetic patients with chronic foot ulcers. The present study supports the view that diabetic chronic foot ulcers ought to be seen as a sign of cardiac disease, although further research is needed to elucidate this issue.

Physical activity is a predictor of all-cause mortality in patients with intermittent claudication

OBJECTIVE

We examined whether all-cause mortality was predicted by physical activity level in peripheral arterial disease (PAD) patients limited by intermittent claudication.

METHODS

This retrospective, natural history follow-up study determined survival status of each patient. Patients with stable symptoms of intermittent claudication were evaluated in the Geriatrics, Research, Education, and Clinical Center at the Maryland Veterans Affairs Health Care System (MVAHCS) at Baltimore between 1994 and 2002, and were classified into a physically sedentary group (n = 299) or a physically active group (n =135), and followed in 2004 using the Social Security Death Index.

RESULTS

Median follow-up was 5.33 years (range = 0.25 to 8.33 years) for the physically active group, and 5.0 years (range = 0.17 to 8.5 years) for the sedentary group. At follow-up, 108 patients (24.9%) had died, consisting of 86 (28.8%) in the sedentary group and 22 (16.3%) in the active group. Unadjusted risk of mortality was lower (P = .005) in the physically active group (hazard ratio [HR] = 0.510, 95% CI = 0.319 to 0.816). In multivariate Cox proportional hazards analysis, age (HR = 1.045, 95% CI = 1.019 to 1.072, P < 0.001), body mass index (BMI) (HR = 0.943, 95% CI = 0.902 to 0.986, P = 0.009), ankle-brachial index (ABI) (HR = 0.202, 95% CI = 0.064 to 0.632, p = 0.006), and physical activity status (HR = 0.595, 95% CI = 0.370 to 0.955, P = .031) were predictors of mortality.

CONCLUSION

Patients limited by intermittent claudication who engage in any amount of weekly physical activity beyond light intensity at baseline have a lower mortality rate than their sedentary counterparts who perform either no physical activity or only light-intensity activities. The protective effect of physical activity persists even after adjusting for other predictors of mortality, which include age, ABI, and BMI.

Patterns of ambulatory activity in subjects with and without intermittent claudication

PURPOSE

This study compared the patterns of ambulatory activity in subjects with and without intermittent claudication.

METHODS

The study participants were 98 subjects limited by intermittent claudication and 129 controls who were matched for age, gender, and race. Subjects were assessed on their ambulatory activity patterns for 1 week with a small, lightweight step activity monitor attached to the ankle using elastic Velcro (Velcro Industries BV, Manchester, NH) straps above the lateral malleolus of the right leg. The step activity monitor recorded the number of strides taken on a minute-to-minute basis, the time spent ambulating, and the time and number of strides measured at low (<15 strides/min), medium (15 to 30 strides/min), and high (>30 strides/min) cadences.

RESULTS

Subjects with intermittent claudication took fewer total strides each day than the controls (3149 +/- 1557 strides/d vs 4230 +/- 1708 strides/d; P < .001) and fewer strides at medium (1228 +/- 660 strides/day vs 1638 +/- 724 strides/day; P = .001) and high (766 +/- 753 strides/day vs 1285 +/- 1029 strides/day; P < .001) cadences. Subjects with intermittent claudication also had a lower daily average cadence than the controls (11.8 +/- 2.9 strides/min vs 13.5 +/- 3.1 strides/min; P < .001) and spent less total time ambulating each day (264 +/- 109 min/day vs 312 +/- 96 min/day; P = .034), primarily at medium (58 +/- 30 min/day vs 75 +/- 32 min/day; P < .001) and at high (19 +/- 17 min/day vs 30 +/- 22 min/day; P = .001) cadences.

CONCLUSION

Intermittent claudication is associated with lower total daily ambulatory activity owing both to less time ambulating and to fewer strides taken while ambulating, particularly at moderate and high cadences.

Large and Small Vessels Atherosclerosis: Similarities and Differences

Atherosclerosis is a systemic, multifocal disease leading to a various symptoms and clinical events. Beyond disparities related to the organs involved, some differences might exist according to whether the lesions occur in the large (proximal) or small (distal) arteries. Atherosclerotic lesions occur predominantly in the large vessels first, and more distal lesions occur with aging. Proximal lesions are usually more evolving, especially with higher rates of unstable plaques in the proximal segments of coronary arteries. Racial differences regarding lesion distribution exist, with higher rates of distal lesions observed in races other than caucaians. Despite conflicting results found in each vascular territory, there is a suggestion of a stronger association between large vessel disease and smoking and dyslipidemia, whereas diabetes appears more specific for small vessel disease. Hypertension is more frequently reported in intracranial than in extracranial cerebrovascular disease. Preliminary studies report inflammatory markers preferably associated to large-vessel atherosclerosis. Proximal lesions in 1 territory are more frequently associated with concomitant lesions in other territories. Geometric, hemodynamic, and histologic particularities in large and small vessels may at least partially explain these differences, and some recent data point out different biologic properties of the endothelium according to its location.

Hyperhomocysteinemia in patients with arterial occlusive disease

PURPOSE

Hyperhomocysteinemia (HHCA) is defined as an independent risk factor for atherothrombotic vascular disease; therefore, screening for HHCA is recommended. However, the incidence and characteristics of HHCA in patients with vascular disease remain unclear. We conducted this study in an attempt to resolve these issues.

METHODS

This nonrandomized prospective study included 56 patients who were admitted with occlusive arterial disease (group I), and 39 control patients without occlusive arterial disease (group II). We recorded all the demographic data of both groups and collected blood samples for fasting homocysteine, vitamin B(12), and folic acid. All of the patients were followed up and the results were compared.

RESULTS

The mean concentration of homocysteine was 12.69 +/- 3.82 micromol/l in group I and 10.46 +/- 5.08 micromol/l in group II (P = 0.00048). In group I, the mean homocysteine levels for patients aged > or =70 years and those aged <70 years were 13.74 +/- 3.02 and 11.55 +/- 4.15 micromol/l, respectively (P = 0.021). There was no significant difference in mortality between the patients with HHCA and those with normal homocysteine levels during follow-up.

CONCLUSION

The incidence of hyperhomocysteinemia was higher in the patients with occlusive vascular disease than in the control patients. More evidence of the association with vitamins B(12) and folate and the benefits of homocysteine-lowering therapy is needed since we found no relationship between these vitamins and homocysteine in this study.

Metabolic syndrome impairs physical function, health-related quality of life, and peripheral circulation in patients with intermittent claudication

PURPOSE

This study was conducted to (1) examine the effect of metabolic syndrome on intermittent claudication, physical function, health-related quality of life, and peripheral circulation in patients with peripheral arterial disease (PAD), and (2) determine whether peripheral vascular function was predictive of intermittent claudication and physical function in patients with metabolic syndrome.

METHODS

Patients limited by intermittent claudication and who had metabolic syndrome (n = 133) were compared with those without metabolic syndrome (n = 201). Patients were assessed on metabolic syndrome characteristics, PAD-specific measures consisting of ankle/brachial index and claudication distances, physical function measures, health-related quality of life, and calf blood flow and transcutaneous oxygen tension responses after 3 minutes of vascular occlusion.

RESULTS

Initial claudication distance (mean +/- SD) was 29% shorter (P = .018) in patients with metabolic syndrome than in the controls (128 +/- 121 meters vs 180 +/- 166 meters), and absolute claudication distance was 22% shorter (P = .025) in those with metabolic syndrome (319 +/- 195 meters vs 409 +/- 255 meters). Furthermore, patients with metabolic syndrome had lower peak oxygen uptake (P = .037), a shorter 6-minute walk distance (P = .027), lower values on six domains of health-related quality of life (P < .05), reduced calf hyperemia (P = .028), and greater calf ischemia (P < .001) after vascular occlusion. In the group with metabolic syndrome, calf ischemia was correlated with initial claudication distance (r = 0.30, P = .004), absolute claudication distance (r = 0.40, P < .001), and peak oxygen uptake (r = 0.52, P < .001).

CONCLUSION

Metabolic syndrome worsens intermittent claudication, physical function, health-related quality of life, and peripheral circulation in patients with PAD. Calf ischemia in those with metabolic syndrome was predictive of intermittent claudication and physical function. The additive burden of metabolic syndrome thus places patients who are limited by intermittent claudication at an even greater risk for living a functionally dependent lifestyle. Aggressive risk-factor modification designed to treat components of metabolic syndrome should be evaluated for efficacy in modifying physical and vascular function in patients with intermittent claudication.

Does nutrition have a role in peripheral vascular disease?

Peripheral vascular disease (PVD) is a manifestation of systemic atherosclerosis in the lower limbs, and PVD patients have a 3- to 5-fold increased risk of cardiovascular mortality compared with age-matched controls. Nevertheless, recent reports show how PVD patients are undertreated with regard to CVD risk-factor reduction and the use of lipid-lowering or antiplatelet drugs. There is appreciable evidence that demonstrates the beneficial effects of certain nutrients and dietary habits in the prevention of CVD, but there has been little attention paid to the role of nutrients in PVD. The purpose of the present review is to provide an overview of our understanding of how foods could possibly benefit PVD. In the last few decades, several nutrients have arisen as potentially health-promoting in PVD. While nutritional interventions in PVD show positive clinical effects for fish oil, carnitine or vitamin E, others such as olive oil or vitamin C seem to interact only at a biochemical level by decreasing risk factors. Moreover, only epidemiological associations exist for the potential role of fibre, folates or vitamin B6 in this disease. In all cases, the limited data available provide no clear-cut evidence in favour of the clinical benefit of nutritional interventions aimed at reducing risk factors and ameliorating symptoms in PVD patients. No practical recommendations can be given at this stage, and further studies are clearly needed.

Peripheral arterial disease in diabetic patients selected from a primary care setting: Implications for nursing practice

Although the care of patients with diabetes is increasingly provided in primary care, there is relatively little information on the prevalence and long-term progression of asymptomatic peripheral arterial disease (PAD) in diabetic populations selected from primary care settings. The aims of this study were to investigate prevalence and progression of PAD in 146 diabetic patients, and to compare mortality with 113 nondiabetic controls over a 7-year period. The prevalence of PAD in individual pedal arteries varied between 28.6% in the right posterior tibial artery to 48.8% in the left peroneal artery. During the 7-year period, 34.25% of the diabetic subjects died, and 17.5% moved to other locations. Of the remaining 70 patients, 35 (50%) showed no change in ankle-brachial index and 35 (50%) did show change. Comparison of risk factors between those who did and did not show evidence of progression revealed (1) a strong, significant, independent association between hyperglycemia (measured by plasma HbA1c) and progression of PAD among the diabetic population; and (2) a strong association between progression of the disease and family history of diabetes and ischemic vascular disease. There was a high death rate (34.25%) among the diabetic group, which was greater than for the age- and sex-matched nondiabetic controls (13.2%) drawn from the same practice. This high mortality was significantly related (P < .001) to the presence of PAD identified during first-year assessment. Once PAD develops in association with diabetes the long-term prognosis is poor and carries a high mortality rate mainly because of cardiovascular and cerebrovascular diseases. Both progression and mortality were significantly related to poor diabetic control. The role of the primary care nurse in assessing such patients by using Doppler-assisted measurements is one that should be expanded with the massive increase in the number of diabetic patients in the coming years.

Epidemiology and pathophysiology of peripheral arterial disease

Evidence that both asymptomatic and symptomatic peripheral arterial disease (PAD) represent an independent risk for cardiovascular morbidity and mortality has triggered a resurgence in epidemiologic and clinical interest in PAD. Between 8 and 12 million people in the United States are presumed to have PAD, and as the US population ages the incidence of PAD is expected to increase. Epidemiologic studies have shown that the prevalence of PAD among men and women is similar, and autopsy studies of young adults have shown a high frequency of advanced atherosclerotic lesions in distal abdominal aorta by the second decade of life. The pathophysiology of PAD is complex and has not been studied thoroughly. Additional research to understand the pathophysiologic mechanisms in disease-specific circulatory beds is crucial for the advancement of medical therapy for PAD.

Effect of postmenopausal hormone replacement on atherosclerosis in femoral arteries

OBJECTIVES

On the basis of epidemiological and experimental data, it has been supposed that hormone replacement therapy (HRT) inhibits atherosclerosis in postmenopausal women. This randomized controlled trial examined whether 1 mg 17beta-estradiol daily, combined cyclically with 0.025 mg gestodene in every month (HRT 1), or in every third month (HRT 2) slows the increase of intima-media thickness in femoral arteries compared with no HRT.

METHODS

Healthy postmenopausal women (n=321) with an increased risk for future vascular disease as indicated by >1 mm of intima-media thickness in the carotid arteries were equally randomized to one of the three groups for 48 weeks. Ultrasound scans of femoral arteries were recorded at study start and study end, together with a thorough clinical examination and laboratory work-up.

RESULTS

Complete scans were obtained in 260 of the 264 subjects who participated until study end. Mean maximum intima-media thickness of four femoral artery segments (common and superficial, both sides) was 0.93+/-0.37 mm (mean+/-S.D.) at study start. It increased by 0.02+/-0.05, 0.02+/-0.05, and 0.03+/-0.05 mm in the HRT 1, HRT 2 and no HRT groups, respectively (HRT 1 versus no HRT, HRT 2 versus no HRT; both P>0.2). Compared with no HRT, HRT significantly lowered follicle stimulating hormone, low-density lipoprotein cholesterol, and fibrinogen.

CONCLUSIONS

In this 1-year trial, irrespective of the progestogen dose used, HRT with 1 mg 17 beta-estradiol did not inhibit progression of femoral artery atheroslerosis in postmenopausal women with subclinical vascular disease.

The impact of diabetes on arterial reconstructions for multilevel arterial occlusive disease11Presented at the 28th Annual Symposium on Vascular Surgery of the Society for Clinical Vascular Surgery, Rancho Mirage, California, March 15–19, 2000

PURPOSE

Critical limb ischemia due to multilevel arterial occlusive disease often may be treated with an inflow procedure alone; however, a subset patients require a subsequent infrainguinal revascularization for persistence of their symptoms. As diabetic patients typically exhibit a pattern of extensive distal arterial disease, we sought to determine if the presence of diabetes mellitus altered the need for an outflow procedure after inflow bypass.

METHODS

A total of 504 patients undergoing inflow bypass for occlusive disease and lower extremity ischemia between 1990 and 1998 were entered prospectively into a computerized vascular registry. Inflow bypass procedures performed were as follows: aortofemoral (370; 73%), axillofemoral (56; 11%), femorofemoral (81; 16%). Of these patients, 79 required subsequent outflow bypass for unresolved ischemic symptoms. Multiple logistic regression analysis was used to analyze the effects of diabetes and multiple other risk factors on the need for an additional outflow procedure.

RESULTS

The indications for surgery were limb salvage (78%) and disabling claudication (22%). Overall morbidity was 17.7% (hematoma, 3.8%; wound infection, 2.5%; graft occlusion, 1.3%; myocardial infarction, 2.5%; acute renal failure,1.3%; pulmonary failure, 2.5%; pneumonia, 3.8%). Overall mortality was 0%. Diabetic patients comprised a greater proportion of the total number of patients requiring inflow bypass (301 of 504) as well as a greater proportion of patients requiring inflow and outflow procedures (47 of 79). Diabetes was determined not to be an independent risk factor for the need for multiple revascularization procedures by multiple logistic regression analysis (P >0.10).

CONCLUSION

Although patients with diabetes are predisposed to the development of distal arterial occlusive disease, in this study the subgroup of diabetic patients who present with aortoiliac occlusive disease were no more likely than patients without diabetes to require multiple levels of revascularization. These findings provide little rationale for simultaneous inflow and outflow procedures based on the presence of diabetes alone.

Reduction of aortic wall motion inhibits hypertension-mediated experimental atherosclerosis

Hypertension is a well-known risk factor for coronary artery disease and carotid and lower extremity occlusive disease. Surgically induced hypertension in hypercholesterolemic animals results in increased aortic wall motion and increased plaque formation. We tested the hypothesis that reduction in aortic wall motion, despite continued hypertension, could reduce plaque formation. New Zealand White rabbits (n=26) underwent thoracic aortic banding to induce hypertension and were fed an atherogenic diet for 3 weeks. In 13 rabbits, a segment of aorta proximal to an aortic band was externally wrapped to reduce wall motion. All animals were fed an atherogenic diet for 3 weeks. Four groups were studied: 1, coarctation control (no wrap, n=7); 2, coarctation with loose wrap (n=6); 3, coarctation with firm wrap (n=7); and 4, control (noncoarcted, n=6). Wall motion, blood pressure, and pulse pressure were measured at standard reference sites proximal and distal to the coarctation by use of intravascular ultrasound. Quantitative morphometry was used to measure intimal plaque. Mean arterial pressure and cyclic aortic wall motion were equally increased proximal to the aortic coarctation in all 3 coarcted rabbit groups compared with the control group (P:<0.001). Wall motion in the segment of aorta under the loose and firm wraps was no different from the control value. The external wrap significantly reduced intimal thickening in the 4 groups by the following amounts: group 1, 0.30+/-0.03 mm(2); group 2, 0.06+/-0.02 mm(2); group 3, 0. 04+/-0.02 mm(2); and group 4, 0.01+/-0.01 mm(2) (P:<0.001). Localized inhibition of aortic wall motion in the lesion-prone hypertensive aorta resulted in significant reduction in intimal plaque formation. These data suggest that arterial wall cyclic motion may stimulate cellular proliferation and lipid uptake in experimental atherosclerosis.

Hyperhomocysteinaemia is not associated with isolated crural arterial occlusive disease: The Hoorn Study

OBJECTIVES

Hyperhomocysteinaemia is an independent risk factor for peripheral arterial disease (PAD). The localization of peripheral arterial disease is clinically relevant, because proximal (aortoiliac and femoropopliteal) disease is associated with a particularly poor overall prognosis, whereas isolated distal (i.e. crural) disease is associated with a better overall prognosis. The aim of the study was to investigate whether the strength of the association between hyperhomocysteinaemia and peripheral arterial disease differs according to the localization of the anatomical obstruction.

DESIGN

Fasting serum total homocysteine (tHcy) was measured in an age-, sex- and glucose-tolerance stratified random sample (n = 631) of a 50- to 75-year-old general Caucasian population. History of a peripheral arterial reconstruction was recorded. Aortoiliac, femoropopliteal and crural arterial obstructions were registered by means of Doppler flow velocity curves.

RESULTS

The median serum tHcy level was 12.2 micromol L-1 (interquartile range: 10.0-15.3) in men and 10.7 micromol L-1 (interquartile range: 9.0-13.3) in women. The prevalences of aortoiliac, femoropopliteal and crural obstructions were 2.1%, 2.7% and 11.9%, respectively. After adjustment for age, sex, systolic blood pressure, current smoking, serum cholesterol and diabetes mellitus, the odds ratios (95% confidence interval) per 5 micromol L-1 tHcy increment were 1.41 (1.05-1.89) for aortoiliac, 1.03 (0. 70-1.52) for femoropopliteal and 0.82 (0.59-1.15) for crural obstructions. Finally, diabetes mellitus, HbA1c and current smoking were significantly associated with crural and femoropopliteal disease, whereas systolic blood pressure was significantly associated with aortoiliac obstructions.

CONCLUSIONS

The present study indicates that hyperhomocysteinaemia is associated with aortoiliac but not with isolated crural arterial occlusive disease.

Prognostic importance of lower extremity arterial disease in patients undergoing coronary revascularization in the Bypass Angioplasty Revascularization Investigation (BARI)

OBJECTIVES

The purpose of this study was to evaluate the prevalence and prognostic importance of lower extremity arterial disease (LEAD) in patients with multivessel coronary artery disease.

BACKGROUND

The presence of clinically evident LEAD increases the risk of death in patients with known coronary artery disease. Because studies have lacked noninvasive measures of subclinical LEAD, the true prognostic importance of lower extremity atherosclerosis in this population has probably been underestimated.

METHODS

Ankle blood pressures were measured in 405 consecutive patients with angiographically documented multivessel coronary disease from seven Bypass Angioplasty Revascularization Investigation (BARI) sites and a parallel study site within 3 years of enrollment. Lower extremity arterial disease was defined as an ankle/arm systolic blood pressure ratio of 0.90 or less.

RESULTS

Among patients studied, 69 (17%) had LEAD. These patients were more likely to be current smokers, treated for diabetes, older and present with unstable angina compared with patients without LEAD. Among patients who underwent coronary arterial bypass grafting, major complications occurred in 2.8% of those without LEAD compared with 20.7% of those with LEAD (p = 0.002). Five-year mortality rates were similar for symptomatic LEAD (14%) and asymptomatic LEAD (14%). Patients without LEAD had a 3% mortality. After adjusting for baseline differences, the relative risk of death was 4.9 times greater for patients with LEAD compared with those without (95% confidence interval [CI]: 1.8, 13.4, p < 0.01).

CONCLUSIONS

Patients with LEAD have a significantly higher risk of death than patients without LEAD, regardless of the presence of symptoms. An abnormal ankle/arm index is a strong predictor of mortality and can be used to further stratify risk among patients with multivessel coronary artery disease.

Oxidation of LDL and extent of peripheral atherosclerosis

Evidence has accumulated for oxidative modification of low-density lipoproteins (LDL) to play an important role in the atherogenic process. Therefore, we investigated the relation between susceptibility of LDL to oxidation and risk of peripheral atherosclerosis among 249 men between 45 and 80 years of age. The ankle-arm index was calculated for both legs as the ratio of systolic blood pressure in the leg divided by the arm systolic blood pressure. The lowest of both ankle-arm indices was used to categorize subjects. Thirty-nine men with an ankle-arm index < 1.00 (20% cut-off point of distribution) were classified as subjects with peripheral atherosclerosis. Subjects with peripheral atherosclerosis reported more often the use of a special diet and the use of antihypertensive medication, aspirin and coumarin derivatives. No significant differences in total, LDL and HDL cholesterol and triglycerides were present between groups. Resistance time and maximum rate of oxidation were measured ex vivo using copper-induced LDL oxidation. Subjects with peripheral atherosclerosis had a significantly lower resistance time, whereas the maximum rate of oxidation tended to be increased in subjects with peripheral atherosclerosis. Odds ratios (ORs, and 95% confidence interval) for the successive tertiles of resistance time were 1.00 (reference), 0.37 (0.15-0.89) and 0.37 (0.16-0.86) (p(trend) < 0.01). ORs for the successive tertiles of maximum rate of oxidation were 1.00 (reference), 1.34 (0.47-3.82) and 1.50 (0.55-4.15). This inverse association was borderline significant (p(trend) = 0.07). These results support an association between LDL oxidation and the development of peripheral atherosclerosis.

Smoking history is related to free-living daily physical activity in claudicants

PURPOSE

To determine whether smoking history was related to free-living daily physical activity in peripheral arterial occlusive disease (PAOD) patients with intermittent claudication, and whether the effect of smoking history on physical activity level persisted after controlling for group differences in ambulatory function, peripheral circulation, and body composition.

METHODS

Patients were separated into three groups: those who never smoked (N = 35), those who had a lower pack-year history of smoking (< or =40 pack-yr; N = 33), and those who had a higher pack-year history (>40 pack-yr; N = 30). Free-living daily physical activity was assessed by activity monitors (an accelerometer and a pedometer) worn on each hip over 2 consecutive weekdays. Patients also were characterized on ambulatory function, peripheral circulation, and body composition because of their relationship with physical activity.

RESULTS

A progressive decline (P < 0.001) in free-living daily physical activity with increasing smoking exposure was obtained from the accelerometer in the nonsmokers (482 +/- 36 kcal x d(-1); mean +/- SE), smokers with a lower pack-year history (361 +/- 37 kcal x d(-1)), and smokers with a higher pack-year history (227 +/- 23 kcal x d(-1)). A similar decline was found with the pedometer data (P < 0.001). After controlling for group differences in 6-min walk distance and in calf transcutaneous heating power, group differences in free-living daily physical activity were no longer significant.

CONCLUSION

Progressive decrements in free-living daily physical activity with greater levels of smoking exposure in PAOD patients are primarily due to smoking-related impairments in ambulatory function and peripheral circulation.

Cigarette smoking shortens the duration of daily leisure time physical activity in patients with intermittent claudication

PURPOSE

The authors determined (1) whether peripheral arterial occlusive disease (PAOD) patients who smoke have a reduction in either the duration or intensity of daily physical activities compared with nonsmoking patients, and (2) whether group differences in the pattern of physical activity persisted after controlling for potential confounding variables.

METHODS

A total of 170 smokers and 201 nonsmokers who had quit smoking for at least 1 year prior to investigation were studied. Physical activity patterns were measured using the Minnesota Leisure Time Physical Activity (LTPA) questionnaire. Patients also were characterized on potential covariates such as demographics, comorbid conditions, cardiovascular risk factors, ambulatory measures, peripheral hemodynamics, and anthropometric measures.

RESULTS

The smokers were 37% less physically active than the nonsmokers (87 +/- 90 versus 139 +/- 121 kcal/day; P = 0.027). The reduced total LTPA in the smokers was due to a 28% shorter duration of performing activities (26 +/- 7 versus 36 +/- 22 min/day; P = 0.031), and a 3% lower mean intensity of the activities (3.3 +/- 1.0 versus 3.8 +/- 0.8 kcal/min; P = 0.038). The distance score on the Walking Impairment Questionnaire and the hip circumference were significant covariates of the LTPA measures. After adjusting for these covariates, the total LTPA remained 29% lower in the smokers (P = 0.039), the mean daily duration of LTPA remained 20% lower (P = 0.043), but the mean intensity of LTPA was no longer different between the groups.

CONCLUSION

Compared with their nonsmoking counterparts, claudicants who smoke have a reduced total LTPA because they engage in activities of similar intensity for a shorter duration of time.

Hyperhomocysteinemia is associated with an increased risk of cardiovascular disease, especially in non-insulin-dependent diabetes mellitus: a population-based study

A high serum total homocysteine (tHcy) level is an independent risk factor for cardiovascular disease. Because it is not known whether the strength of the association between hyperhomocysteinemia and cardiovascular disease is similar for peripheral arterial, coronary artery, and cerebrovascular disease, we compared the three separate risk estimates in an age-, sex-, and glucose tolerance-stratified random sample (n=631) from a 50- to 75-year-old general white population. Furthermore, we investigated the combined effect of hyperhomocysteinemia and diabetes mellitus with regard to cardiovascular disease. The prevalence of fasting hyperhomocysteinemia (>14.0 micromol/L) was 25.8%. After adjustment for age, sex, hypertension, hypercholesterolemia, diabetes, and smoking, the odds ratios (ORs; 95% confidence intervals) per 5-micromol/L increment in tHcy were 1.44 (1.10 to 1.87) for peripheral arterial, 1.25 (1.03 to 1.51) for coronary artery, 1.24 (0.97 to 1.58) for cerebrovascular, and 1.39 (1.15 to 1.68) for any cardiovascular disease. After stratification by glucose tolerance category and adjustment for the classic risk factors and serum creatinine, the ORs per 5-micromol/L increment in tHcy for any cardiovascular disease were 1.38 (1.03 to 1.85) in normal glucose tolerance, 1.55 (1.01 to 2.38) in impaired glucose tolerance, and 2.33 (1.11 to 4.90) in non-insulin-dependent diabetes mellitus (P=.07 for interaction). We conclude that the magnitude of the association between hyperhomocysteinemia and cardiovascular disease is similar for peripheral arterial, coronary artery, and cerebrovascular disease in a 50- to 75-year-old general population. High serum tHcy may be a stronger (1.6-fold) risk factor for cardiovascular disease in subjects with non-insulin-dependent diabetes mellitus than in nondiabetic subjects.

Physical activity is related to ankle/brachial index in subjects without peripheral arterial occlusive disease

The purpose of this study was to determine whether physical activity level was directly and independently related to the ankle/brachial systolic blood pressure index (ABI) in subjects without peripheral arterial occlusive disease (PAOD). A total of 353 subjects between the age of 38 and 88 years (63.7 +/- 9.1 years; mean +/- standard deviation) who had ABI values > or = 1.00 were studied. The sample consisted of 230 men and 123 women, of whom 274 were caucasian and 79 were African-American. Subjects were characterized on blood pressure, physical activity level from validated questionnaires, anthropometry, plasma lipoprotein lipids, and smoking history. The ABI (1.16 +/- 0.13) was related to physical activity obtained from the Minnesota Leisure Time Physical Activity (LTPA) questionnaire (r = 0.413, P < 0.001). Multiple regression analysis identified race, hypertension, current smoking status, and body mass index (BMI) as cardiovascular risk factors that were independently related to ABI. After controlling for these variables, the relationship between ABI and physical activity persisted (partial r = 0.329, P < 0.001). Thus, physical activity was positively related to ABI in subjects free of PAOD, and the relationship between physical activity and ABI persisted after controlling for race, hypertension, current smoking status, and BMI. It is concluded that adopting a physically active lifestyle is associated with a reduced risk of developing PAOD.

Intermittent claudication. A risk profile from The Framingham Heart Study

BACKGROUND

Intermittent claudication identifies persons at increased risk for death and disability.

METHODS AND RESULTS

Using 38-year follow-up data for the original cohort in the Framingham Heart Study, we developed an intermittent claudication risk profile. Intermittent claudication occurred in a total of 381 men and women. Age, sex, serum cholesterol, hypertension, cigarette smoking, diabetes, and coronary heart disease were associated with an increased risk for claudication and were included in the profile. A pooled logistic regression model was used to compute the probability of intermittent claudication for specified levels of risk factors.

CONCLUSIONS

The intermittent claudication risk profile allows physicians to identify high-risk individuals during a routine office visit and can be used to educate patients about modifiable risk factors, particularly smoking and blood pressure. Improved compliance with risk factor modification strategies may result in a beneficial impact on survival.

Variation in cardiovascular risk factors by angiographic site of lower limb atherosclerosis

OBJECTIVE

To determine differences in the levels of the cardiovascular risk factors, cigarette smoking, serum lipids and blood pressure, between three groups of patients with different sites of lower limb atherosclerosis.

DESIGN

Cross-sectional survey of a consecutive series of patients with symptoms of either intermittent claudication or rest pain.

METHODS AND MATERIALS

One hundred and ninety-two men and women who had undergone angiography were classified using the Bollinger scoring system into groups with predominantly aortoiliac, femoropopliteal or dual-site disease. History of cigarette smoking, serum cotinine, serum thiocyanate, total cholesterol and HDL cholesterol were estimated. Systolic and diastolic pressures were measured and the ankle brachial pressure index (ABPI) was calculated.

RESULTS

Eighty-five patients were classified as having femoropopliteal disease, 34 aortoiliac disease and 73 dual-site disease. After adjusting for age, sex and severity of disease, aortoiliac patients were significantly younger (p </- 0.001), more likely to be female and current smokers, and had the highest levels of diastolic blood pressure. Life time cigarette consumption (pack-years) and total cholesterol concentrations were highest in femoropopliteal disease. Patients with dual-site disease were more likely to have had a myocardial infarction and angina pectoris (p </- 0.05). Systolic blood pressure was also highest in this group.

CONCLUSION

different levels of cardiovascular risk factors may predispose individuals to atherosclerosis at different sites in the lower limb. Large population studies would be required to delineate the risks more precisely.

Hypertension-enhanced monocyte adhesion in experimental atherosclerosis

PURPOSE

Hypertension is a known clinical risk factor for atherosclerosis. In experimental atherosclerosis, monocyte adhesion to the endothelial surface is enhanced and is considered to be an important early stage in plaque formation. We tested the hypothesis that hypertension enhances monocyte adhesion in experimental atherosclerosis.

METHODS

Twenty-two New Zealand White rabbits were fed an atherogenic diet for 3 weeks to induce plaque formation. Aortic coarctation was created in eight rabbits by wrapping a Dacron band around the midportion of the descending thoracic aorta (stenosis group), whereas six rabbits underwent banding without aortic constriction (no stenosis group). Eight rabbits served as nonoperated controls. Monocyte binding to the aortic endothelial surface was counted with epifluorescent microscopy on standard aortic segments proximal and distal to the band. Immunohistochemistry was performed for the following antibodies: VCAM-1, RAM11, CD11b, and factor VIII.

RESULTS

Mean blood pressure was 89 +/- 3 mm Hg in the aorta proximal to the stenosis, compared with 64 +/- 4 mm Hg in the no stenosis group and 74 +/- 3 mm Hg in the control group (p < 0.01). The mean aortic blood pressure gradient across the stenosis was 16 +/- 2 mm Hg in the stenosis group, whereas the aortic blood pressure gradient was 0.2 +/- 0.6 mm Hg in the no stenosis group and -0.3 +/- 0.4 mm Hg in the control group (p < 0.001). Monocyte adhesion to the aortic endothelial surface proximal to the stenosis was increased twofold compared with adhesion to the aorta distal to the stenosis and compared with the proximal aorta in the control group (p < 0.02). The proximal-to-distal aortic ratio of monocyte binding was enhanced in the stenosis group (2.2) compared with the no stenosis (0.76) and control (0.83) groups (p < 0.01). The intima area of the aorta proximal to the stenosis was significantly increased compared with the proximal aortas in the no stenosis and control groups (p < 0.01). RAM11, CD11b, and endothelial VCAM-1 expression were enhanced in the hypertensive region proximal to the stenosis.

CONCLUSIONS

In the hypertensive region in the aorta proximal to the stenosis, monocyte adhesion and endothelial VCAM-1 expression were increased, with intimal thickening and accumulation of macrophages. These findings suggest that hypertension may promote atherosclerotic plaque formation by enhancing monocyte adhesion.

Plasma homocysteine and severity of atherosclerosis in young patients with lower-limb atherosclerotic disease

Elevated plasma homocysteine levels are recognized as an independent risk factor for atherosclerotic disease. It is not known (1) whether the severity of atherosclerotic disease is related to hyperhomocyst(e)inemia or (2) whether any such relation differs between fasting and post-methionine loading plasma homocysteine levels. Therefore, in 171 consecutive patients under 55 years of age with first symptoms of lower-limb disease, we examined the relation between severity of atherosclerosis and plasma homocysteine concentration. Severity of atherosclerotic disease was estimated from the prevalence of coronary artery disease and cerebrovascular disease and from the angiographic extent of lower-limb disease. Plasma homocysteine was measured after a period of fasting and in response to methionine loading (0.1 g/kg). In multivariate analysis, the prevalence of coronary artery disease plus cerebrovascular disease was related to both fasting and postmethionine homocysteine levels (odds ratio [OR] for the upper quartile versus the lower three quartiles, 2.8, 95% confidence interval [CI], 1.1 to 7.5; and OR 3.0, 95% CI, 1.1 to 7.8, respectively). The extent of lower-limb disease was weakly related to the fasting homocysteine level (partial correlation coefficient, .12; P = .17) and more strongly related to the postmethionine homocysteine level (partial correlation coefficient, .25; P = .003). These relations tended to be more pronounced in women than in men. They were independent of age, total serum cholesterol, blood pressure, and smoking habit. We concluded that the severity of atherosclerotic disease in young patients with lower-limb atherosclerotic disease is associated with high postmethionine and fasting homocysteine concentrations.

Morbidity, mortality, and antihypertensive treatment effects by extent of atherosclerosis in older adults with isolated systolic hypertension

BACKGROUND AND PURPOSE

The Systolic Hypertension in the Elderly Program (SHEP) demonstrated a significant reduction in stroke and coronary event rates among participants randomly assigned to active blood pressure treatment. Selected participants were evaluated for peripheral atherosclerosis and followed up for cardiovascular events beyond the end of the SHEP trial. Antihypertensive treatment effects were evaluated based on the presence or absence of clinical or subclinical atherosclerosis.

METHODS

As an ancillary study to SHEP, 190 participants at the Pittsburgh center were evaluated for peripheral atherosclerosis, defined as either an internal carotid stenosis (by duplex scan) or lower extremity arterial disease (identified by ankle blood pressure). Participants were subsequently followed up for cardiovascular events.

RESULTS

Estimates of 4-year mortality rates were 4.8% for participants with no atherosclerosis, 16.7% for those with subclinical atherosclerosis, and 23% among those with clinical evidence of atherosclerosis (P < .001). Fatal plus nonfatal cardiovascular event rates were 10.9%, 29.8%, and 58.3% for the three groups, respectively (P < .001). Differences remained significant after adjustment for age, sex, treatment assignment, smoking, and high-density lipoprotein cholesterol. Individuals assigned to placebo at the beginning of SHEP had higher cardiovascular event rates than individuals assigned to active treatment (P = .011), with the most striking difference 3 or more years after the end of the SHEP trial. When this analysis was stratified by the presence or absence of detectable atherosclerosis, the absolute treatment effect was largest among those with evidence of disease.

CONCLUSIONS

Individuals with systolic hypertension and evidence of peripheral atherosclerosis are at high risk for cardiovascular events. Targeting this group for antihypertensive therapy would result in the prevention of a large number of cardiovascular events.

Peripheral arterial disease in relation to glycaemic level in an elderly Caucasian population: the Hoorn study

We investigated the cross-sectional association between peripheral arterial disease and glycaemic level in an age, sex, and glucose tolerance stratified random sample from a 50-74-year-old Caucasian population. Subjects treated with oral hypoglycaemic agents or insulin were classified as having known diabetes mellitus (KDM) (n = 67). Using two oral glucose tolerance tests, and based on World Health Organisation criteria, all other participants were categorized as having a normal (NGT) (n = 288), an impaired (IGT) (n = 170), or a diabetic (NDM) (n = 106) glucose tolerance. Prevalence rates of ankle-brachial pressure index less than 0.90 were 7.0%, 9.5%, 15.1% and 20.9% in NGT, IGT, NDM and KDM subjects, respectively (chi-square test for linear trend: p < 0.01). Prevalence rates of any peripheral arterial disease (ankle-brachial pressure index < 0.90, at least one monophasic or absent Doppler flow curve or vascular surgery) were 18.1%, 22.4%, 29.2% and 41.8% in these categories (chi-square test for linear trend: p < 0.0001). The prevalence of any peripheral arterial disease was higher in KDM and NDM than in NGT (p < 0.03, p < 0.0001, respectively), whereas no statistically significant difference was demonstrated between IGT and NGT. The same applied when using the ankle-brachial pressure index criterion. Logistic regression analyses showed that any arterial disease was significantly associated with HbA1c, fasting and 2-h post-load plasma glucose after correction for cardiovascular risk factors (odds ratios and 95% confidence intervals 1.35; 1.10-1.65 per %, 1.20; 1.06-1.36 and 1.06; 1.01-1.12 per mmol/l, respectively), whereas it was not associated with fasting and 2-h post-load specific insulin. Ankle-brachial pressure indices were not associated with either plasma glucose parameters or insulin in univariate or multivariate analyses. In conclusion, parameters of glucose tolerance are independently associated with any peripheral arterial disease, whereas insulin is not.