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Background: Peripheral arterial disease (PAD) is characterized by myofiber degeneration and loss of function in muscles of the lower limbs. Human enterovirus (HEV) infection has been implicated in the pathogenesis of a number of muscle diseases. However, its association with PAD has not been studied. In this study, we tested the hypothesis that infectious HEV is present in skeletal muscle of patients with PAD and is associated with severity of disease., Methods and Results: Gastrocnemius biopsies from 37 patients with PAD and 14 controls were examined for the presence of HEV RNA, viral capsid protein, viral RNA copy number, and viral infectivity. HEV RNA was detected in 54% of the biopsies from patients with PAD but was not detected in muscle biopsies from control patients. This difference in prevalence among PAD and control patients was significant at P<0.001. Viral RNA copy numbers were increased significantly at the later stages of disease; Fontaine Stage IV (10(5.50) copies/mg muscle wet weight, at P<0.005) and Stage III (10(4.87) copies/mg, at P<0.010) compared to Stage II (10(2.50) copies/mg). Viral replication was confirmed by the presence of the negative-strand of viral RNA in all specimens positive for HEV RNA. Cultures of HeLa and human skeletal muscle cells treated with muscle homogenates showed HEV replication and the presence of HEV capsid protein., Conclusion: Our data identified infectious HEV in the gastrocnemius of PAD patients but not in controls. Viral copy number and prevalence of infection were higher in the later stages of disease. Our data point to the need for further studies to determine the contribution of HEV infection to the pathophysiology of PAD.

Objective: Claudication is the most common manifestation of peripheral arterial disease, producing significant ambulatory compromise. Our study evaluated patients with bilateral lower limb claudication and characterized their gait abnormality based on advanced biomechanical analysis using joint torques and powers., Methods: Twenty patients with bilateral claudication (10 with isolated aortoiliac disease and 10 with combined aortoiliac and femoropopliteal disease) and 16 matched controls ambulated on a walkway while 3-dimensional biomechanical data were collected. Patients walked before and after onset of claudication pain. Joint torques and powers at early, mid, and late stance for the hip, knee, and ankle joints were calculated for claudicating patients before and after the onset of claudication pain and were compared to controls., Results: Claudicating patients exhibited significantly reduced hip and knee power at early stance (weight-acceptance phase) due to decreased torques produced by the hip and knee extensors. In mid stance (single-limb support phase), patients had significantly reduced knee and hip power due to the decreased torques produced by the knee extensors and the hip flexors. In late stance (propulsion phase), reduced propulsion was noted with significant reduction in ankle plantar flexor torques and power. These differences were present before and after the onset of pain, with certain parameters worsening in association with pain., Conclusions: The gait of claudication is characterized by failure of specific and identifiable muscle groups needed to perform normal walking (weight acceptance, single-limb support, and propulsion). Parameters of gait are abnormal with the first steps taken, in the absence of pain, and certain of these parameters worsen after the onset of claudication pain., (Copyright (c) 2010 Society for Vascular Surgery. Published by Mosby, Inc. All rights reserved.)

Background: Claudication secondary to peripheral arterial disease leads to reduced mobility, limited physical functioning, and poor health outcomes. Disease severity can be assessed with quantitative clinical methods and qualitative self-perceived measures of quality of life. Limited data exist to document the degree to which quantitative and qualitative measures correlate. The current study provides data on the relationship between quantitative and qualitative measures of symptomatic peripheral arterial disease., Method: This descriptive case series was set in an academic vascular surgery unit and biomechanics laboratory. The subjects were symptomatic patients with peripheral arterial disease patients presenting with claudication. The quantitative evaluation outcome measures included measurement of ankle-brachial index, initial claudication distance, absolute claudication distance, and self-selected treadmill pace. Qualitative measurements included the Walking Impairment Questionnaire (WIQ) and the Medical Outcomes Study Short Form-36 (SF-36) Health Survey. Spearman rank correlations were performed to determine the relationship between each quantitative and qualitative measure and also between the WIQ and SF-36., Results: Included were 48 patients (age, 62 +/- 9.6 years; weight, 83.0 +/- 15.4 kg) with claudication (ABI, 0.50 +/- 0.20). Of the four WIQ subscales, the ankle-brachial index correlated with distance (r = 0.29) and speed (r = 0.32); and initial claudication distance and absolute claudication distance correlated with pain (r = 0.40 and 0.43, respectively), distance (r = 0.35 and 0.41, respectively), and speed (r = 0.39 and 0.39 respectively). Of the eight SF-36 subscales, no correlation was found for the ankle-brachial index, initial claudication distance correlated with Bodily Pain (r = 0.46) and Social Functioning (r = 0.30), and absolute claudication time correlated with Physical Function (r = 0.31) and Energy (r = 0.30). The results of both questionnaires showed reduced functional status in claudicating patients., Conclusions: Initial and absolute claudication distances and WIQ pain, speed, and distance subscales are the measures that correlated the best with the ambulatory limitation of patients with symptomatic peripheral arterial disease. These results suggest the WIQ is the most specific questionnaire for documenting the qualitative deficits of the patient with claudication while providing strong relationships with the quantitative measures of arterial disease. Future studies of claudication patients should include both quantitative and qualitative assessments to adequately assess disease severity and functional status in peripheral arterial disease patients.