Impairment of microcirculation and energy metabolism in intermittent claudication: beneficial effects of exercise training

Although in peripheral arterial disease (PAD) the primary determinant of inadequate blood supply to the affected limb during exercise is a flow-limiting lesion of a conduit artery, there is a large body of evidence that impairment of microcirculation and skeletal muscle energy metabolism play a relevant role in the reduced working ability of affected individuals. This review was conceived to cast some light on this topic, paying special attention to the functional benefits of exercise training (ET) in the treatment of claudicant patients. In PAD, the ischemia induced by maximal exercise increases oxidative stress, inflammation and endothelial dysfunction. Perturbation of the endothelial homeostasis results in increased adhesiveness of leukocytes and platelets, and in reduced vasodilator capability. These events, expression of the interplay between inflammation and endothelium, provoke an obstacle in the microcirculation with a reduction in the nutritive blood flow, leading to acidosis and impaired energy metabolism in skeletal muscle, with consequent reduced exercise tolerance. ET counteracts these effects by improving walking ability and quality of life in patients with intermittent claudication, thus representing the gold standard in the treatment of PAD

Abdominal aortic aneurysm in patients affected by intermittent claudication: prevalence and clinical predictors

BACKGROUND: Abdominal aortic aneurysm (AAA) is a frequent cause of death among elderly. Patients affected by lower extremity peripheral arterial disease (LE-PAD) seem to be particularly at high risk for AAA. We aimed this study at assessing the prevalence and the clinical predictors of the presence of AAA in a homogeneous cohort of LE-PAD patients affected by intermittent claudication. METHODS: We performed an abdominal ultrasound in 213 consecutive patients with documented LE-PAD (ankle/brachial index ≤ 0.90) attending our outpatient clinic for intermittent claudication. For each patient we registered cardiovascular risk factors and comorbidities, and measured neutrophil count. RESULTS: The ultrasound was inconclusive in 3 patients (1.4%), thus 210 patients (169 males, 41 females, mean age 65.9 ± 9.8 yr) entered the study. Overall, AAA was present in 19 patients (9.0%), with a not significant higher prevalence in men than in women (10.1% vs 4.9%, p = 0.300). Patients with AAA were older (71.2 ± 7.0 vs 65.4 ± 9.9 years, p = 0.015), were more likely to have hypertension (94.7% vs 71.2%, p = 0.027), and greater neutrophil count (5.5 [4.5 - 6.2] vs 4.1 [3.2 - 5.5] x 10(3)/μL, p = 0.010). Importantly, the c-statistic for neutrophil count (0.73, 95% CI 0.60 - 0.86, p = 0.010) was higher than that for age (0.67, CI 0.56-0.78, p = 0.017). The prevalence of AAA in claudicant patients with a neutrophil count ≥ 5.1 x 10(3)/μL (cut-off identified at ROC analysis) was as high as 29.0%. CONCLUSIONS: Prevalence of AAA in claudicant patients is much higher than that reported in the general population. Ultrasound screening should be considered in these patients, especially in those with an elevated neutrophil count

Femoral Plaque Echogenicity and Cardiovascular Risk in Claudicants

ObjectivesThe present study was designed to verify whether the evaluation of femoral plaque echogenicity might be a useful tool for cardiovascular risk assessment in patients affected by lower extremity peripheral arterial disease.BackgroundLower extremity peripheral arterial disease is a common manifestation of atherosclerosis and is associated with a high risk of developing major cardiovascular events. Vulnerable atherosclerotic plaque plays a central role in the occurrence of acute ischemic events in different vascular territories. Furthermore, atherosclerosis is a systemic disease, and the presence of an unstable atherosclerotic plaque in a certain vascular district, characterized by low echogenicity at B-mode ultrasound, is associated to a greater prevalence of unstable plaques in other vascular beds.MethodsFemoral plaque echogenicity of 246 claudicants with ankle/brachial index ≤0.90 was evaluated at B-mode ultrasound by visual analysis and by calculating the grayscale median (GSM) value. In these patients, the occurrence of myocardial infarction and stroke was prospectively assessed.ResultsFemoral GSM values and plaque types assessed by visual analysis were highly correlated by Spearman analysis (rho = 0.905, p < 0.001). During a median follow-up of 30 months, 32 patients (13%) had a major cardiovascular event. Compared with patients without events, those who experienced an event during the follow-up had a lower femoral plaque GSM value (42.9 ± 26.2 vs. 58.8 ± 19.3, p = 0.002) and a higher prevalence of hypoechoic femoral plaque at visual analysis (68.8% vs. 19.6%, p < 0.001). At Cox analysis, femoral GSM showed an inverse relationship with cardiovascular risk, even after adjustment for possible confounders (hazard ratio: 0.96, 95% confidence interval [CI]: 0.95 to 0.98, p < 0.001). Furthermore, patients with hypoechoic femoral plaques at visual analysis had a 7.24-fold increased cardiovascular risk compared with patients with hyperechoic plaques after adjustment for possible confounders (95% CI: 3.23 to 16.22, p < 0.001).ConclusionsThis study demonstrates that the presence of hypoechoic atherosclerotic femoral plaques is associated with higher cardiovascular risk in lower extremity peripheral arterial disease patients

Effects of Successful Percutaneous Lower Extremity Revascularization on Cardiovascular Outcome in Patients with Peripheral Arterial Disease

Background. Lower extremity peripheral arterial disease (LE-PAD) reduces walking capacity and is associated with an increased cardiovascular risk. Endovascular revascularization of LE-PAD improves walking performance and quality of life. In the present study, we determined whether successful lower limbs revascularization also impacts cardiovascular outcome in LE-PAD patients. Methods. 479 consecutive LE-PAD patients at stage II of Fontaine’s classification, with ankle/brachial index ≤0.90 and one or more stenosis >50% in at least one leg artery, were enrolled in the study. According to the Trans-Atlantic Inter Society Consensus II recommendations, 264 (55.1%) underwent percutaneous lower extremity angioplasty (PTA group), while 215 (44.9%) were managed with conservative therapy (MT group). The incidence of major cardiovascular events (including cardiovascular death, myocardial infarction, ischemic stroke, coronary and carotid revascularizations) was prospectively analyzed by Kaplan-Meier curves. Crude and adjusted HRs (95% CI) of developing a cardiovascular event were calculated by Cox analysis. Results. No baseline differences were observed among the groups, except for a lower maximum walking distance in the PTA group. During a median follow-up of 21 months (12.0–29.0), the incidence of cardiovascular events was markedly lower in PTA compared to MT patients (6.4% vs. 16.3%; p=0.003), and patients in the MT group showed a 4.1-fold increased cardiovascular risk compared to patients in the PTA group, after adjustment for potential confounders (95% CI 1.22-13.57, p=0.023). Conclusions. This study shows that successful revascularization of LE-PAD patients affected by intermittent claudication, in addition to improving functional status, reduces the occurrence of future major cardiovascular events