A multicenter randomized controlled study to evaluate whether neuromuscular electrical stimulation improves the absolute walking distance in patients with intermittent claudication compared with best available treatment.

OBJECTIVE: To assess the clinical efficacy of a neuromuscular electrical stimulation (NMES) device to improve the absolute walking distance in patients with intermittent claudication as an adjunct to the local standard care available at the study sites compared with local standard care alone. METHODS: This open, multicenter, randomized controlled trial included eight participating centers in England. Sites are equally distributed between those that provide supervised exercise therapy programs and those that do not. Patients with intermittent claudication meeting the eligibility criteria and providing consent will be randomized, depending on the center type, to either NMES and locally available standard care or standard care alone. The primary end point is change in absolute walking distance at 3 months (the end of the intervention period) by treadmill testing. Secondary outcomes include quality of life, compliance with the interventions, economic evaluation of the NMES device, and lower limb hemodynamic measures to further the understanding of underlying mechanisms. Recruitment commenced in March 2018 and will continue for a total of 15 months. The Neuromuscular Electrical Stimulation Improves the Absolute Walking Distance in Patients with Intermittent Claudication trial is funded by the UK Efficacy and Mechanism Evaluation Programme, Medical Research Council, and National Institute for Health Research partnership.

Homocysteine lowering interventions for peripheral arterial disease and bypass grafts.

BACKGROUND: Elevated plasma levels of the amino acid homocysteine (hyperhomocysteinaemia) are associated with narrowing or blocking of the arteries (atherosclerosis). Treatment to lower homocysteine levels has been shown to be both effective and cheap in healthy volunteers. However, the impact of reducing homocysteine levels on the progression of atherosclerosis and patency of the vessels after treatment for atherosclerosis is still unknown and forms the basis for this review. This is the second update of a review first published in 2002. OBJECTIVES: To assess the effects of plasma homocysteine lowering therapy on the clinical progression of disease in people with peripheral arterial disease (PAD) and hyperhomocysteinaemia including, as a subset, those who have undergone surgical or radiological intervention. SEARCH METHODS: For this update, the Cochrane Peripheral Vascular Disease Group Trials Search Co-ordinator (TSC) searched the Specialised Register (last searched January 2013) and CENTRAL (2012, Issue 12). Trial databases were searched by the TSC (January 2013) for details of ongoing and unpublished studies. We also searched the reference lists of relevant articles. SELECTION CRITERIA: Randomised trials in which participants with PAD and hyperhomocysteinaemia were allocated to either homocysteine lowering therapy or no treatment, including participants before and after surgical or radiological interventions. DATA COLLECTION AND ANALYSIS: Two review authors independently assessed trial quality and extracted the data. Information on adverse events was collected from the trials. MAIN RESULTS: Two randomised trials with a total of 161 participants were included in this review. The studies did not report on mortality and rate of limb loss. One randomised trial with a total of 133 participants showed that there was a significant improvement in ankle brachial index (ABI) in participants who received folic acid compared with placebo (mean difference (MD) 0.07, 95% confidence interval (CI) 0.04 to 0.11, P < 0.001) and in participants who received 5-methyltetrahydrofolate (5-MTHF) versus placebo (MD 0.05, 95% CI 0.01 to 0.10, P = 0.009). A second trial with a total of 18 participants showed that there was no difference (P non-significant) in ABI in participants who received a multivitamin B supplement (mean ± SEM: 0.7 ± 01) compared with placebo (mean ± SEM: 0.8 ± 0.1). No major events were reported. AUTHORS' CONCLUSIONS: Currently, no recommendation can be made regarding the value of treatment of hyperhomocysteinaemia in peripheral arterial disease. Further, well constructed trials are urgently required.

Value of thromboelastography in the assessment of platelet function.

Thromboelastography (TEG) is a useful measure of coagulation. Modified TEG (that is with the addition of a GP IIb/IIIa receptor antagonist) has been used to assess the contribution of the fibrinogen-platelet interaction to TEG parameters (in particular the maximum amplitude, MA). Modified TEG was compared with other investigations of platelet function to assess its sensitivity in both normal subjects and in patients with peripheral arterial disease (PAD), a condition associated with activated platelets. Blood was collected from eight healthy subjects and 12 PAD patients. Platelet function was measured by TEG, flow cytometry (using PAC-1, P-selectin, GP IIIa and GP Ib murine antibodies) and platelet aggregometry (spontaneous and ADP-induced) in the presence and absence of tirofiban (a GP IIb/IIIa receptor antagonist). TEG showed a statistically significant reduction in MA with tirofiban at 0.4 mg/L and an increase in k (kinetic time; which indicates how fast clot strength is increasing once clotting starts) at 0.2 and 0.4 mg/L of tirofiban in both healthy subjects and PAD patients. Flow cytometry showed a significant decrease in the PAC-1 binding index (at 0.2 mg/L). This finding was compatible with the significant reductions found in spontaneous and ADP-induced platelet aggregation. However, aggregometry and flow cytometry were more sensitive indicators of platelet inhibition than the TEG parameters. TEG does not provide a comprehensive or sensitive reflection of impaired platelet function. If TEG is used as an index of severely impaired platelet function, we recommend that the k parameter should be used as well as MA. TEG should be supplemented by other methods of platelet function assessment wherever possible.