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Screening for Peripheral Arterial Disease: An Update

Peripheral arterial disease (PAD) is common disease and associated with significant morbidity and mortality. PAD is caused due to fatty deposition on artery walls that leads to narrowing of the arteries and blockage in the main blood vessels of the lower limb, which may results in discomfort or pain in the legs during walk, as well as poor quality life and an increased risk of death because of heart and cerebrovascular diseases [1-6]. Risk factors for PAD are shown in Figure 1. The main aim of this review is to focus on the status and progress of screening for peripheral arterial disease.


Introduction
Peripheral arterial disease (PAD) is common disease and associated with significant morbidity and mortality. PAD is caused due to fatty deposition on artery walls that leads to narrowing of the arteries and blockage in the main blood vessels of the lower limb, which may results in discomfort or pain in the legs during walk, as well as poor quality life and an increased risk of death because of heart and cerebrovascular diseases [1][2][3][4][5][6]. Risk factors for PAD are shown in Figure 1. The main aim of this review is to focus on the status and progress of screening for peripheral arterial disease.
A prevalence of 10% of people fewer than 70 years and 15% to 20% of people over 70 years, and an estimated prevalence of 13% in the age group over 50 years of age is estimated. Asymptomatic PAD may be responsible for up to 75% of cases and only 10% of sufferers have typical intermittent claudication. Many patients suffer from significant functional limitations, and the most severe cases are at risk of limb loss [7]. Physical examination shows decreased or absence of pulses in the legs and feet, and the color of the legs become pale when elevated above horizontal. The ratio of the leg to arm pressure is normally 1.0, but a ratio of less than 0.9 indicates that a significant blockage may be observed in leg artery. The severity of the reduction of ankle brachial index is classed as mild illness being 0.71 to 0.9, moderate disease being from 0.5 to 0.7, severe disease is less than 0.5 [7]. Two systematic reviews and meta-analysis, and contrasted the screening ABI and mortality and amputations results were included in a study. Screening for PAD has averaged 17% (range 1%−42%) and was 1% to 4% in lowrisk populations. In patients with PAD ABI was associated with an increased risk adjusted mortality from all causes (HR 2.99; 95% confidence interval 2.16 to 4.12) and cardiovascular mortality (HR 2, 35, 95% confidence interval 1.91 to 2.89). ABI screening was associated with prognosis and risk stratification for heart disease, although the data on benefits harms and cost-effectiveness of screening are limited [8].
Patients on hemodialysis (n=210) were examined using the anklebrachial index (ABI) and toe-brachial index (TBI). The prevalence of PAD was 38.1%, and 42.5% were diagnosed with TBI <0.6, although ABI ≥ 0.9. The prevalence of cerebrovascular disease was 36.3%, coronary artery disease was 42.5% [9]. A study reported prospective cross-sectional study that included 162 patients who were evaluated and classified into three groups according to their ABI: normal ABI (n=104, values between 1.00 and 1.40); Borderline PAD (n=23, values between 0.91 and 1.00); and patients with PAD (n=35, ≤ 0.90). The presence of intermittent claudication (IC) was assessed using the Edinburgh Claudication Questionnaire and the level of physical activity was assessed by the short version of the International Physical Activity Questionnaire (IPAQ) and functional capacity was assessed by walking distance of 6 minutes (6MWT). The prevalence of PAD was 21.6%. The 6MWT showed a strong correlation with the absence of IC (r=0.785; P < 0.001), moderate correlation with age (r = -0.347; p < 0.001), and weak correlations with IPAQ score (r=0.164; P=0.038) and ABI (r=0.216, P=0.006) [10]. According to another study 100 patients were selected with suspected obstructive sleep apnea (OSA) to PAD, and polysomnography, ankle-brachial index (ABI), central pulse wave velocity, pulse wave index and duplex ultrasonography parameters were recorded for those patients.  [11]. Other study reported about two hundred forty-one Swiss multicenter cohort study (SSCS) of systemic lupus erythematosus (SLE) patients cross being evaluated for peripheral arterial disease (PAD). Patients with (SLE) were compared with a cohort of 193 patients with type 1 diabetes mellitus of the patients within the SSCS, 13.3% who had one or more vascular events: 1.2% PAD. In type-1 diabetes mellitus, 15% had vascular events: 5.6% PAD. Vascular events in patients with SLE were associated with age, duration of disease, dyslipidemia, and hypertension [12]. In a Korean study (72.14 ± 5.15 years) PAD was detected in 79 subjects (4.9%). Current smoking was significantly associated with PAD (P < 0.001) [13]. A design was assessed (n=135) in order to evaluate the prevalence of peripheral arterial disease (PAD) and its related risk factors in prediabetes patients. The prevalence of PAD in diabetes patients was higher than the normal group (8.5% vs. 0.0%) (P < 0.05). The ABI in normal, prediabetes, and diabetes group was (1.11 ± 0.11), (1.09 ± 0.12), and (1.05 ± 0.03) respectively (P < 0.1) [14]. In a meta-analysis (n=43 919) showed that the ABI could reclassify 10-year risk for coronary artery disease (CAD) [15]. In a systematic review assesses the ability of non-invasive screening tests to detect PAD in patients with diabetes mellitus. Thirteen studies reporting sensitivity and specificity were only reliable in the identification or exclusion of PAD [16].
In a study with Familial hypercholesterolemia (FH), the authors assessed 202 patients (51 ± 14 years, 35% of men) with heterozygous FH (90.6% with LDL receptor mutations), and total cholesterol levels of 342 ± 86 mg /dL. The prevalence of PAD was 28.2 %. An independent association between CVD and the diagnosis of PAD was observed (OR=2.50; 95% CI: 1.004 -6.230; p=0.049) [17]. In a prospective cross-sectional study (n=329, aged >50 years) was conducted at a single emergency department were screened. The prevalence of PAD was 10.3% (95% CI7.5-14.1%). The prevalence of symptomatic and asymptomatic PAD was 6.4% (95% CI 4.2-9.6%) and 3.9% (95% CI 2.3-6.7%) [18]. Atherosclerosis diabetes is the major source of CVD in patients with diabetes mellitus types 1 and 2 (T1D and T2D). The diabetes is able to impair morphological and functional characteristics of the vascular walls and this condition plays as precursor of atherosclerotic disease. Family history of diabetes mellitus is related to increase in metabolic alterations predisposing to diabetes and increases cardiovascular risk profile of individuals. Although this is not supported by scientific evidences, many observational studies revealed its relationship [19][20][21][22][23][24][25].
Several methods [flow-mediated vasodilatation (FMD); anteroposterior abdominal aorta diameter (APAO); intima-media thickness of the common carotid artery (CCA-IMT); arterial stiffness; trying to assess their function, but have many limitations general characteristics of the population, and should be used according to gender and age [26]. Available evidence shows that PAD is common in patients with multiple cardiovascular risk factors and is associated with significant morbidity and mortality, but at the moment do not get benefits of your routine screening. Mortality and limb loss is greater in chronic asymptomatic PAD, guidelines suggest that we should treat an asymptomatic ABI 0.7 aggressively with smoking cessation, drugs, and lifestyle intervention.