Peripheral Artery Disease (PAD) : Its Effects on Bone (AMICOS)

Prevalence of PAD and osteoporosis (OP) both get higher with age. Clinical and epidemiologic evidence have showed an increased cardiovascular risk in OP and bone loss and fragility fractures in patient with cardiovascular disease. This study will examine the relationship between vascular disease in legs and sBMD and vBMD at trabecular and cortical sites and bone microarchitecture.

The primary goal of our study is to determinate if presence of PAD is associated with lower sBMD and vBMD values at the tibias, assuming that BMD should be more alterate in the predominant vascular impairement site. Our secondary objectives are to : determine if severity of PAD quantified by ankle brachial index ABI is associated to a decrease of BMD values defined by T-Score at the left hip, spine and legs, but also with volumetric values, assessed by HRpQCT at the non dominant radius and at both tibias. determine the prevalence of osteoporosis in our population To evaluate the relationships between ; lipids and bone parameters vit D and parathormone with PAD severity levels of physical activity and both vascular and bone impairments

PAD patients, diagnosis after undergoing an echo-doppler in the Vascular Medicine Department of Orleans regional Hospital

DXA : BMD assessment at the left hip, rachis and both legs HRpQCT : Volumic Bone mineral density, cortical and trabecular parameters, at the non dominant radius and legs Biological samples

Relations between areal BMD results (DXA) at the hip and lumbar spine and the ankle brachial index measured at the two legs.

The following micro structural parameters assessed by HRpQCT at both tibias will be : Dtrab : volumetric trabecular bone mineral density (mg HA/ cm3), Dinn : inner trabecular bone density (mg HA/cm3), Dmeta: metatrabecular bone density (mg HA/cm3), Dcort: volumetric cortical bone mineral density (mg HA/cm3), D100: total volumetric bone mineral density (mg HA/cm3), Tb.Th: trabecular thickness (mm), Tb.N: trabecular number (mm-1); Tb.Sp: trabecular separation (mm), Ct.Th: cortical thickness (mm); Tb1.NSD: intra-distribution individual separation (mm), BV / TV: trabecular bone volume (%).

comparison between bone microarchitecture parameters at the tibia: the parameters will be compared between the most severely limb and the contralateral one.

We will study the relation between lipidic and bone parameters. Potential correlations between on the one hand (lipid parameters: total and HDL-cholesterol, triglyceridemia, LDL-cholesterol calculation) and on the other hand bone parameters: vBMD volumetric bone mineral density (mg HA/cm3) Ct.BMD: cortical volumetric bone mineral density (mg/cm3); Tb.BMD: trabecular volumetric bone mineral density (mg HA/cm3)

The risk of fracture at 10 years will be evaluate by the Fracture Risk Assessment Tool (FRAX) survey. The FRAX® tool was developed by the then WHO Collaborating Centre for Metabolic Bone Diseases (1991-2010) at the University of Sheffield. It was launched in 2008 following approximately 10 years of meta-analyses of a variety of risk factors for osteoporotic fracture. Although not the only fracture prediction tool available, FRAX® is the only risk calculator which has been calibrated to rates of fracture and mortality per individual country and has been shown to identify a risk amenable to available treatments.

Cardiovascular risk assessment using the SCORE tool (Systematic Coronary Risk Estimation). Four levels of risk are defined: Very high cardiovascular risk ≥ 10%; High risk, which includes subjects with major or particularly high risk factors (familial hypercholesterolemia, severe hypertension, etc.) and those with a score between 5 and 10%; Moderate risk, which concerns patients with a score between 1 and 5%; Low risk, which includes subjects with a score < 1%;

comparison between bone microarchitecture at the tibia and of the radius. The following micro structural parameters assessed by HRpQCT at tibias and radius will be : Dtrab : volumetric trabecular bone mineral density (mg HA/ cm3), Dinn : inner trabecular bone density (mg HA/cm3), Dmeta: metatrabecular bone density (mg HA/cm3), Dcort: volumetric cortical bone mineral density (mg HA/cm3), D100: total volumetric bone mineral density (mg HA/cm3), Tb.Th: trabecular thickness (mm), Tb.N: trabecular number (mm-1); Tb.Sp: trabecular separation (mm), Ct.Th: cortical thickness (mm); Tb1.NSD: intra-distribution individual separation (mm), BV / TV: trabecular bone volume (%).

Inclusion Criteria: PAD patients defined by an Ankle brachial index < 0.9 Written consent Patient affiliated with a social security organism Exclusion Criteria: Age < 18 years Pregnancy or risk of pregnancy Patients Under guardianship Patient with known PAD who had been previously treated by surgery or endovascular pathway

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