Peripheral arterial disease in diabetic and nondiabetic patients: a comparison of severity and outcome

Peripheral arterial disease in patients with diabetes

Peripheral arterial disease (PAD) is a chronic, lifestyle-limiting disease and is an independent predictor of cardiovascular and cerebrovascular ischemic events. Despite the recognition that PAD is associated with a marked increase in the risk of ischemic events, this particular manifestation of systemic atherosclerosis is largely underdiagnosed and undertreated. The risk of PAD is markedly increased among individuals with diabetes, and ischemic event rates are higher in diabetic individuals with PAD than in comparable non-diabetic populations. Consequently, early diagnosis and treatment of PAD in patients with diabetes is critically important in order to reduce the risk of cardiovascular events, minimize the risk of long-term disability, and improve quality of life. A diagnosis of PAD in patients with diabetes mandates a multi-faceted treatment approach, involving aggressive risk-factor modification, antiplatelet therapy, and revascularization procedures. The American Diabetes Association recently issued a consensus statement on the epidemiology, pathophysiology, diagnosis, and management of PAD in patients with diabetes. This article will review the clinical implications of the consensus statement and highlight the treatment options available in order to help prevent future ischemic events in diabetic individuals with PAD.

Assessment of critical limb ischemia in patients with diabetes: comparison of MR angiography and digital subtraction angiography

OBJECTIVE

The purpose of our study was to evaluate the diagnostic accuracy of hybrid MR angiography by comparison with digital subtraction angiography (DSA) in diabetic patients with critical limb ischemia.

SUBJECTS AND METHODS

Thirty-one patients prospectively underwent both hybrid MR angiography and DSA. The hybrid MR angiography study consisted of high-resolution MR angiography of a single calf and foot using a contrast-enhanced 3D gradient-echo volumetric interpolated breath-hold examination with surface coils, followed by three-station bolus chase MR angiography with a dedicated peripheral vascular coil. Two blinded reviewers separately analyzed maximum-intensity-projection hybrid MR angiograms and DSA images. The peripheral vessels were divided into 10 anatomic segments for review. The status of each segment was graded as normal, stenosis less than 50% in diameter, stenosis greater than 50%, or occluded. The sensitivity and specificity of hybrid MR angiography were determined using DSA as the gold standard. Treatment options were considered separately from the results of each examination.

RESULTS

Among 310 analyzed segments, the sensitivities of hybrid MR angiography for stenosis and occlusion were, respectively, 95% and 95% for reviewer 1 and 96% and 90% for reviewer 2. The specificities of hybrid MR angiography for stenosis and occlusion were, respectively, 98% and 98% for reviewer 1 and 98% and 99% for reviewer 2. In 25 patients (81%), the quality of bolus chase MR angiography images was insufficient to assess runoff arteries. All treatments proposed on the basis of DSA findings were endorsed by hybrid MR angiography findings. Eleven more treatments were formulated on the basis of hybrid MR angiography findings. Of these, four were due to overestimation of stenosis on MR angiography and seven were due to the detection of patent infrageniculate arteries on hybrid MR angiography that were not detected on DSA.

CONCLUSION

Hybrid MR angiography depicts runoff arteries not seen on DSA. Hybrid MR angiography may be useful for treatment planning in selected diabetic patients with critical limb ischemia.

Association of Cardiovascular Risk Factors with Pattern of Lower Limb Atherosclerosis in 2659 Patients Undergoing Angioplasty

OBJECTIVES

Aim of this study is to correlate distribution pattern of lower limb atherosclerosis with cardiovascular risk factor profile of patients with peripheral arterial occlusive disease (PAD).

PATIENTS AND METHODS

Analysis is based on a consecutive series of 2659 patients (1583 men, 1076 women, 70+/-11 years) with chronic PAD of atherosclerotic origin undergoing primary endovascular treatment of lower extremity arteries. Pattern of atherosclerosis was grouped into iliac (n=1166), femoropopliteal (n=2151) and infrageniculate (n=888) disease defined according to target lesions treated. A multivariable multinomial logistic regression analysis was performed to assess relation with age, gender and classical cardiovascular risk factors (diabetes mellitus, arterial hypertension, hypercholesterolemia, cigarette smoking) using femoropopliteal disease as reference.

RESULTS

Iliac disease was associated with younger age (RRR 0.95 per year of age, 95%-CI 0.94-0.96, p<0.001), male gender (RRR 1.32, 95%-CI 1.09-1.59, p=0.004) and cigarette smoking (RRR 2.02, 95%-CI 1.68-2.42, p<0.001). Infrageniculate disease was associated with higher age (RRR 1.02, 95%-CI 1.01-1.02, p<0.001), male gender (RRR 1.23, 95%-CI 1.06-1.41, p=0.005) and diabetes mellitus (RRR 1.68, 95%-CI 1.47-1.92, p<0.001). Hypercholesterolemia was less prevalent in patients with lesions below the knee (RRR 0.82, 95%-CI 0.71-0.94, p=0.006), whereas no distinct pattern was apparent related to arterial hypertension.

CONCLUSION

Clinical phenotype of peripheral atherosclerosis varies with prevalence of cardiovascular risk factors suggesting differences in mechanisms involved in iliac as compared with infrageniculate lesions. Identification of molecular mechanism might have influence on future therapeutic strategies in PAD patients.

The US experience with cilostazol in treating intermittent claudication

The management of peripheral arterial disease (PAD) patients with intermittent claudication (IC) requires both aggressive risk management and targeted symptomatic therapies. The phosphodiesterase inhibitor cilostazol is the only US Food and Drug Administration (FDA) approved medication to demonstrate consistent benefits on both objective measures of exercise capacity and subjective measures of everyday functioning and quality of life. Pentoxifylline is also approved by the FDA for the treatment of claudication, but with less clinical benefit than cilostazol. This report will provide an overview of cilostazol's role in the treatment of patients with IC. Data will be presented regarding the safety and efficacy demonstrated by cilostazol in clinical trials, as well as the effects of risk-factor control, exercise therapy, revascularization, and experimental drugs on the treatment of claudication in the PAD population. Based on the available evidence, a comprehensive approach to claudication management is recommended.

Peripheral Angioplasty as the First-choice Revascularization Procedure in Diabetic Patients with Critical Limb Ischemia: Prospective Study of 993 Consecutive Patients Hospitalized and Followed Between 1999 and 2003

OBJECTIVE

To evaluate the effectiveness of peripheral angioplasty (PTA) as the first-choice revascularisation procedure in diabetic patients with critical limb ischemia (CLI).

DESIGN

Prospective study.

METHODS

PTA was employed as first choice revascularisation in a consecutive series of diabetic patients hospitalized for CLI between January 1999 and December 2003.

RESULTS

PTA was successful performed in 993 patients. Seventeen (1.7%) major amputations were carried out. One death and 33 non-fatal complications were observed. Mean follow-up was 26+/-15 months. Clinical restenosis was observed in 87 patients. The 5 years primary patency was 88%, 95% CI 86-91%. During follow-up 119 (12.0%) patients died at a rate of 6.7% per year.

CONCLUSIONS

PTA as the first choice revascularisation procedure is feasible, safe and effective for limb salvage in a high percentage of diabetic patients. Clinical restenosis was an infrequent event and PTA could successfully be repeated in most cases.

Changing perspectives in diabetic foot ulcer management

Diabetic foot ulceration is a serious complication of diabetes mellitus; it is the cause of more than half of nontraumatic lower limb amputations. Diabetic foot ulcers are the major cause of hospital admission for diabetic patients. Treatment costs are high. There have been advances in managing diabetic foot ulceration with the development of new dressings, growth factors, skin substitutes, and other novel approaches to stimulating wound healing. The management of vascular disease in the patient with diabetes mellitus is an essential and important consideration. However, the need for a multidisciplinary team to provide good foot care to diabetic patients is still vital for the prevention and treatment of diabetic foot ulceration.

Incidence of Peripheral Arteriosclerotic Complications of the Lower Extremities in Diabetic Patients With Chronic Renal Failure

Patients with diabetes mellitus are at high risk of arteriosclerotic complications. The same is true for those with chronic renal failure (CRF). The present study evaluated clinical factors on the occurrence of peripheral arterial diseases. The severity of peripheral arterial disease was defined as mild (plaque, calcifications) or severe (70% stenosis, obstructions) based upon ultrasonographical examination. Overall in diabetic patients, mild ultrasonographical findings such as plaque and calcification were observed in 25% (17/69) of predialysis patients and in 18% (7/38) of those on hemodialysis (HD). Severe arteriosclerotic findings such as stenosis and obstruction were seen in 42% (29/69) of predialysis patients and in 50% (19/38) of those on HD. The incidence is identical between predialysis patients and patients on HD, regardless of the severity of peripheral arterial diseases. In an attempt to compare diabetics with non-diabetics, the incidence of mild abnormal findings was found in 22% (24/107) of diabetics and in 30% (11/37) of non-diabetics. Similarly, the percentage of patients with severe arteriosclerotic findings was found in 45% (48/107) in diabetics and 11% (4/37) in non-diabetics. The incidence of the severe type findings in the diabetics is significantly more frequent than that in the non-diabetics (P < 0.01, by the chi(2) test). In non-diabetic predialysis patients, the incidence of mild arteriosclerotic findings was observed in 30% (7/23), and 29% (4/14) of non-diabetic patients on HD. Similarly, the percentage of severe type was 9% (2/23) in non-diabetic predialysis patients, and 14% (2/14) in non-diabetic patients on HD. These data are not only supportive of previous data that diabetes is a risk factor for arteriosclerosis, but also suggestive that, even before the initiation of dialysis, patients with CRF are already susceptible to arteriosclerotic assault of peripheral arterial complications.

Greater effect of enhanced pharmacist care on cholesterol management in patients with diabetes mellitus: a planned subgroup analysis of the Study of Cardiovascular Risk Intervention by Pharmacists (SCRIP)

STUDY OBJECTIVE

To determine the effect of enhanced pharmacist care on cholesterol management in patients with and without diabetes mellitus.

METHODS

We conducted a planned subgroup analysis of the Study of Cardiovascular Risk Intervention by Pharmacists (SCRIP), a 54-center randomized trial of pharmacist intervention compared with usual care in patients at high risk for cardiovascular events. The patients involved had atherosclerotic disease or diabetes. We compared the effect of pharmacist intervention in patients with and without diabetes. The primary end point was a composite of performing a fasting cholesterol profile, or adding or increasing the dosage of a cholesterol-lowering drug. Secondary end points were individual components of the primary end point and change in 10-year risk for cardiovascular events, using the Framingham risk equation.

RESULTS

Of the 675 patients enrolled in the SCRIP study, 294 (44%) had diabetes. Enhanced pharmacist care had a more beneficial effect on cholesterol management in those with diabetes (odds ratio [OR] 4.8) than without diabetes (OR 2.1), p=0.01. Secondary end points showed similar trends, and reduction in Framingham risk was greater in patients with diabetes than without.

CONCLUSION

Pharmacist intervention for dyslipidemia appears to have a greater impact in patients with diabetes. Results of this substudy suggest that pharmacists should target this patient group for interventions in cholesterol risk management.

The diabetic foot: from art to science. The 18th Camillo Golgi lecture

Diabetic foot ulceration represents a major medical, social and economic problem all over the world. While more than 5% of diabetic patients have a history of foot ulceration, the cumulative lifetime incidence may be as high as 15%. Ethnic differences exist in both ulcer and amputation incidences, with both being less common in patients of Indian subcontinent origin living in the UK. Foot ulceration results from the interaction of several contributory factors, the most important of which is neuropathy. With respect to the management of acute Charcot neuroarthropathy in diabetes, recent studies suggest that bisphosphonates reduce disease activity as judged not only by differences in skin temperature, but also by assessing markers of bone turnover. The use of the total-contact cast is demonstrated in the treatment of acute Charcot feet and of plantar neuropathic ulcers. Histological evidence suggests that pressure relief results in chronic foot ulcers changing their morphological appearance by displaying some features of an acute wound. Thus, repetitive stresses on the insensate foot appear to play a major role in maintaining ulcer chronicity. It is hoped that increasing research activity in foot disease will ultimately result in fewer ulcers and less amputation in diabetes.

Relationship of high and low ankle brachial index to all-cause and cardiovascular disease mortality: the Strong Heart Study

BACKGROUND

The associations of low (<0.90) and high (>1.40) ankle brachial index (ABI) with risk of all-cause and cardiovascular disease (CVD) mortality have not been examined in a population-based setting.

METHODS AND RESULTS

We examined all-cause and CVD mortality in relation to low and high ABI in 4393 American Indians in the Strong Heart Study. Participants had bilateral ABI measurements at baseline and were followed up for 8.3+/-2.2 years (36 589 person-years). Cox regression was used to quantify mortality rates among participants with high and low ABI relative to those with normal ABI (0.90 < or =ABI < or =1.40). Death from all causes occurred in 1022 participants (23.3%; 27.9 deaths per 1000 person-years), and of these, 272 (26.6%; 7.4 deaths per 1000 person-years) were attributable to CVD. Low ABI was present in 216 participants (4.9%), and high ABI occurred in 404 (9.2%). Diabetes, albuminuria, and hypertension occurred with greater frequency among persons with low (60.2%, 44.4%, and 50.1%) and high (67.8%, 49.9%, and 45.1%) ABI compared with those with normal ABI (44.4%, 26.9%, and 36.5%), respectively (P<0.0001). Adjusted risk estimates for all-cause mortality were 1.69 (1.34 to 2.14) for low and 1.77 (1.48 to 2.13) for high ABI, and estimates for CVD mortality were 2.52 (1.74 to 3.64) for low and 2.09 (1.49 to 2.94) for high ABI.

CONCLUSIONS

The association between high ABI and mortality was similar to that of low ABI and mortality, highlighting a U-shaped association between this noninvasive measure of peripheral arterial disease and mortality risk. Our data suggest that the upper limit of normal ABI should not exceed 1.40.

The diabetes epidemic: a national and global crisis

Diabetes mellitus is a serious problem that will soon reach epidemic proportions in the United States and throughout the world. The incidence of this condition will skyrocket in the next quarter century as demographic changes increase the size of highly susceptible populations (e.g., the elderly and Hispanic communities) and sociocultural developments create a more sedentary populace as well as expose people in developing nations to new risk factors for this disease. Along with substantial direct morbidity and mortality, diabetes is independently associated with the incidence and severity of a variety of cardiovascular illnesses. Individuals with diabetes are substantially more likely than their nondiabetic counterparts to suffer stroke, myocardial infarction, or heart failure, with a worse prognosis following any of these conditions. Many factors may be relevant to this association, but recent studies have elucidated a major role for the metabolic syndrome, which has been shown to be predictive of both diabetes and cardiovascular disease. Consequently, early intervention to control blood glucose levels and other risk factors may mitigate the severity of these conditions, possibly even before the disease begins.

Profilin acts downstream of LDL to mediate diabetic endothelial cell dysfunction

The changes occurring at the luminal surface of endothelial cells in diabetes and their relevance to endothelial dysfunction are poorly characterized in vivo. In this study, we developed an integrated strategy to discover cell surface proteins associated with diabetes and to test their role in endothelial dysfunction. First, a peptide phage display library was screened over the endothelial surface of the intact aorta or in retinal endothelial cells from diabetic and control rats. Then, we purified profilin-1 as a binding partner for one of the diabetic aorta-specific phage. Profilin was increased in the aortic endothelium of human diabetic individuals and streptozotocin-diabetic rats. Furthermore, overexpressing profilin in rat aortic endothelial cells triggered 3 indicators of endothelial dysfunction: increased apoptosis, elevated expression of ICAM-1, and decreased phosphorylation of the vasodilator-stimulated phosphoprotein, a marker for nitric oxide signaling. The changes in ICAM-1 and vasodilator-stimulated phosphoprotein were recapitulated in the diabetic aorta in vivo. LDL and oxysterols elevated profilin in cultured aortic endothelial cells. Interference with the de novo synthesis of profilin abrogated the LDL-mediated increase in ICAM-1 expression. Finally, profilin expression was markedly elevated in atherosclerotic plaques. These data indicate that profilin contributes to endothelial dysfunction in a pathway that is downstream of LDL.

Soft tissue enhancement on time-resolved peripheral magnetic resonance angiography

PURPOSE

To evaluate the incidence and locations of soft tissue enhancement on time-resolved two-dimensional projection magnetic resonance angiography (MRA) of the calf and foot.

MATERIALS AND METHODS

Time-resolved two-dimensional projection MRA of the knee, calf, and foot, performed at 1.5 Tesla using the head coil, was retrospectively reviewed in 326 patients. Soft tissue enhancement of the foot was identified and graded by blinded review. Subsequently, patient medical records were reviewed to determine the presence or absence of diabetes, cellulitis, gangrene, and ulceration of the foot and presence of neuropathic joints.

RESULTS

Enhancing spots were identified in 228 patients. For those feet without clinical abnormalities, diabetic patients had an average of 1.2 enhancing spots per foot, while nondiabetics had only 0.6 (P < 0.001). Higher-grade lesions were more prevalent in diabetics and in heavier patients. Of 64 patients with follow-up, 8 (13%) developed cellulitis (N = 4) or ulceration (N = 4) at the location of an enhancing spot, including 5 diabetic and 3 nondiabetic patients.

CONCLUSION

Pedal soft tissue enhancement frequently occurs on time-resolved gadolinium (Gd):MRA of the feet. The etiology is uncertain, but the high frequency in diabetic patients and observation of progression to cellulitis/ulceration suggest this soft tissue enhancement may identify sites of subclinical pedal soft tissue injury.

Type 2 diabetes mellitus in adolescence: lipid and cardiovascular risk factors

This review discusses the important consequences of dyslipidemia and arteriosclerosis in type 2 diabetes as documented in studies in adults. It then examines the relatively recent upsurge in type 2 diabetes in children and adolescents, its characteristics, and its importance in directing our attention to cardiovascular risk factors in this age group. The discussion concludes with an examination of the information available about arteriosclerosis in the young and about the treatment of hypercholesterolemia in children and adolescents.

Prevalence and risk factors of peripheral arterial obstructive disease in Taiwanese type 2 diabetic patients

The aim of this study was to evaluate the prevalence and risk factors of peripheral arterial obstructive disease (PAD) in Taiwanese type 2 diabetic patients. A total of 610 patients (268 men and 342 women), aged 63.3 +/- 10.8 years, were recruited from a diabetic clinic in a teaching hospital. PAD was diagnosed by an ankle-brachial index (ABI) < 0.9 on either leg. Risk factors studied were age, sex, body mass index (BMI), smoking, diabetes duration, hypertension, insulin therapy, systolic blood pressure (SBP), diastolic blood pressure (DBP), fasting plasma glucose (FPG), serum total cholesterol (TC), and triglyceride (TG). Overall prevalence of PAD was 10.0% without significant sexual difference. Univariate analyses disclosed age, BMI (inverse association), diabetes duration, hypertension, insulin therapy, and SBP as significant risk factors. In stepwise logistic regression, age, SBP, BMI, and insulin therapy were independent risk factors with respective odds ratios (95% confidence intervals, CI) of 1.09 (1.05-1.13), 1.02 (1.01-1.04), 0.88 (0.80-0.96), and 3.37 (1.83-6.19). In conclusion, prevalence of PAD in Taiwanese type 2 diabetic patients was 10.0% and the major risk factors were older age, lower BMI, higher SBP, and insulin therapy. The inverse association between PAD and BMI is contradictory to the general impression that obesity is a risk factor for PAD.

High-risk foot and ankle patients

The surgical treatment of complicated foot and ankle problems requires recognition and appreciation of patient and disease characteristics that may compromise surgical results. Appropriate patient selection is an important factor in obtaining a successful outcome. Modulation and management of these patient characteristics are critical in minimizing complications that are associated with treatment.

Mechanisms underlying the programming of small artery dysfunction: review of the model using low protein diet in pregnancy in the rat

Human and animal studies have shown that unbalanced maternal nutrition is associated with the development of cardiovascular and metabolic disease in adulthood. In the Southampton maternal low protein model (SMLP), protein deprivation (50%) throughout pregnancy in rats leads to elevated blood pressure in adult offspring. Impaired peripheral arterial function may contribute to the cardiovascular dysfunction observed in these offspring. This review discusses the impact of such a dietary insult on the vascular function of resistance arteries from pregnant rats (pF(o)), their offspring (F(1)), the pregnant offspring (pF(1)) and the second generation (F(2)). At each stage, disturbances in endothelium-dependent relaxation were observed, implicating changes in endothelial nitric oxide (NO)-guanylate cyclase (GC) signalling pathway in the vascular adaptations to pregnancy and the programmed effects on offspring.