Lower-Limb Vascularization in Diabetic Patients

Abstract

OBJECTIVE -To investigate, by thallium-201 scanning, circulation in the muscles of the lower limb (LL) in diabetic patients without clinical peripheral vascular disease but with a high cardiovascular risk profile. RESEARCH DESIGN AND METHODS-A total of 80 diabetic patients (76 patients with type 2 diabetes, mean age 57.3 years, duration of diabetes 13.0 Ϯ 7.5 years) with more than one additional cardiovascular risk factor but no claudication were investigated. After stress testing, 1.5 MBq/kg thallium-201 was administered to perform myocardial single-photon emission computed tomography followed by LL scanning. Muscle blood flow was considered abnormal if the asymmetry in thallium-201 uptake between the two buttocks and/or thighs and/or calves was Ͼ10%.RESULTS -Muscle perfusion defects were found in 42% of the patients, mainly in the calves. These defects correlated with retinopathy (P ϭ 0.042) and the HbA 1c level (P ϭ 0.044). In patients with defects in the buttock and/or thigh, the prevalence of nephropathy and retinopathy was higher than in those with isolated defects in the calf (P ϭ 0.032 and 0.023, respectively).CONCLUSIONS -This study suggests that LL scanning coupled with myocardial scintigraphy is a convenient method of investigating peripheral muscle circulation. Proximal perfusion defects in patients without clinical arterial disease are associated with increased prevalence of retinopathy and nephropathy and, therefore, may be due to microvascular disease of LL muscle. Distal defects may indicate silent macrovascular disease of the LL. Diabetes Care 24:870 -874, 2001A fter 38 years of follow-up, the Framingham Heart Study showed that the risk of developing intermittent claudication was increased by associated coronary heart disease and diabetes (1). The prevalence of coronary artery disease and peripheral vascular disease (PVD) is high in the diabetic population (2,3).More than 50% of diabetic patients die from cardiovascular diseases (4), and the morbidity due to PVD is very high (5). Furthermore, claudication is, in turn, a strong predictor of subsequent cardiovascular events (6 -8).In diabetic patients with other risk factors, myocardial scintigraphy is suggestive of silent myocardial ischemia (SMI) in 20 -30% of cases (9). These patients commonly have angiographically normal coronary arteries and endothelial dysfunction, and myocardial microvascular changes are involved (10). Whole-body exercise thallium-201 ( 201 Tl) scintigraphy, performed after stress testing, permits detection of early functional abnormalities of lower-limb (LL) vascularization (11)(12)(13)(14)(15)(16)(17)(18)(19). Furthermore, this test investigates not only macrovascular but also microvascular blood flow (12,19).We performed myocardial 201 Tl scintigraphy after stress testing to detect SMI in a selected population of diabetic patients without claudication and without cardiac symptoms and signs but with a high cardiovascular risk profile. We took this opportunity to perform LL scanning. In particular, we examined the prevalen...

Transcutaneous Oxygen Pressure Measurements on the Buttocks During Exercise to Detect Proximal Arterial Ischemia

“…26 Proximal ischemia with or without claudication is found in 40% of diabetic patient with abnormal whole-body thallium scintigraphy. 13 The present study illustrates, as suggested from recent reports, 12,13 that proximal ischemia even without symptoms is a frequent (and likely underestimated) event.…”

“…In most reported cases, angiography is the only examination that allowed for the diagnosis of isolated internal iliac lesions. 1,2,6,12 It is likely that the real number of patients suffering from proximal ischemia with or without claudication is underestimated 13 because of the lack of effective, noninvasive investigation tools to aid in the diagnosis of this condition. It is controversial whether a more extensive approach toward revascularization of the internal iliac arteries is needed to limit the risk of postsurgical proximal ischemia in aortobifemoral bypass.…”

Skin Blood Flow in the Upper and Lower Extremities of Diabetic Patients with and without Autonomic Neuropathy

“…They speculate that nonuniform disease progression between paired legs may be involved and suggest the possibility of using symmetry-based parameters to develop early markers of subclinical peripheral arterial disease progression. Cosson et al [52]have also described asymmetry between blood flow in the right and left leg. They speculated that lower limb perfusion abnormalities may result not only from macrovascular but also from microvascular disorders, which may be asymmetrically distributed.…”

Lower Limb Pain Caused by Insufficient Muscular Microcirculation

“…Total counts in each of the three levels were then determined by computer, and right-to-left ratios were calculated at each level. A ratio <0.9 or >1.1 at one or several levels defined an abnormal result of lower limb scintigraphy for the level considered, as reported previously [17,19]. The perfusion defects were obvious in some patients, but counting was always performed.…”

“…Briefly, ECG was performed during graded exercise testing on a bicycle ergometer. The results of exercise ECG were interpreted as negative if there were no ischemic changes during exercise [17]. Single-photon emission computed tomography (SPECT) imaging was performed within 5-10 min after the injection of Thallium-201, with the patient in the supine position, using a single-head, wide-angle-lens gamma camera and a low-energy, highresolution collimator.…”