Far infrared treatment on the arteriovenous fistula induces changes in sVCAM and sICAM in patients on hemodialysis.

INTRODUCTION: There is a substantial risk of developing stenosis and dysfunction in the arteriovenous fistula (AVF) in patients on hemodialysis (HD). Far infrared radiation (FIR) is a non-invasive local intervention with a potentially beneficial effect on AVF patency. The underlying mechanism is not clear. It was hypothesized that a single FIR treatment reduces factors of inflammation and promotes endothelial vasodilators in the AVF. METHODS: Forty HD patients with an AVF were included in an open-label intervention study. Patients were randomized to receive either FIR (FIR group) or no FIR (control group). Blood samples were drawn directly from the AVF and from a peripheral vein in the non-AVF arm before (T0) and 40 min after (T40) treatment during a HD session. The changes [median (interquartile range)] in circulating factors of inflammation, endothelial function and vasoreactivity during FIR were measured. RESULTS: In the AVF a single FIR treatment during dialysis resulted in a significantly diminished decrease in soluble vascular cell adhesion molecule, sVCAM [-31.6 (-54.3; 22.1) vs -89.9 (-121.6; -29.3), P = .005] and soluble intercellular adhesion molecule, sICAM [-24.2 (-43.5; 25.3) vs -49 (-79.9; -11.6), P = .02] compared with the control group. Other factors, such as interleukins, nitrite, nitrate and tumor necrosis factor 1, also declined during dialysis, but with no significant differences related to FIR in either the AVF or the non-AVF arm. CONCLUSION: A single FIR treatment attenuated the decrease in sVCAM and sICAM in the AVF compared with a control group during HD. Findings do not support the hypothesis of a vaso-protective effect of FIR. The long-term effects of FIR on the AVF are unknown.

Effect of revascularization on lower extremity muscle function in combined type 2 diabetes and critical limb threatening ischemia.

BACKGROUND: Critical limb-threatening ischemia (CLTI) and type 2 diabetes (T2D) frequently co-exist and often with less favorable outcome after revascularization. The objective was to evaluate the effects of revascularization on muscle function, perfusion and mitochondrial respiration in patients with combined CLTI and T2D. METHODS: A prospective translational observational study. Two groups of patients facing unilateral peripheral revascularization was included: Patients suffering from combined disease with CLTI+T2D (N.=14) and patients suffering from CLTI (N.=15). During pedal exercise testing, calf muscle perfusion was monitored with near-infrared spectroscopy (NIRS) and leg arterial volume flow in the common femoral artery with duplex ultrasound. Calf muscle biopsy and subsequent assessment of mitochondrial respiratory capacity on isolated muscle fibers was performed. Tests was performed before and six weeks after revascularization. RESULTS: After revascularization, patients CLTI+T2D improved in muscle force from 8.48 kg (CI: 7.49-9.46) to 13.11 kg (CI: 11.58-14.63), (P<0.001). Conversely, muscle force in patients suffering from non-diabetic CLTI decreased from 10.03 kg (CI: 9.1-10.96) to 9.73 kg (CI: 8.77-10.69), (P=0.042). Muscle oxygenation during exercise improved more in the CLTI+T2D group (6.36 µM/kg/s [CI: 5.71-7.01] compared to 2.11 µM/kg/s [CI:1.38-2.83] in the CLTI group; P=0.002). No improvement or difference between groups regarding mitochondrial function was detected. CONCLUSIONS: Patients with combined CLTI+T2D, had an unsuspected better effect of revascularization compared to patients with non-diabetic CLTI, in terms of increased muscle force and improved muscle perfusion. Further studies are needed to elucidate the apparent interaction of the CLTI and T2D syndromes.

Ensuring Competency in Open Aortic Aneurysm Repair - Development and Validation of a New Assessment Tool.

OBJECTIVE: The aims of this study were to develop a procedure specific assessment tool for open abdominal aortic aneurysm (AAA) repair, gather validity evidence for the tool and establish a pass/fail standard. METHODS: Validity was studied based on the contemporary framework by Messick. Three vascular surgeons experienced in open AAA repair and an expert in assessment and validation within medical education developed the OPEn aortic aneurysm Repair Assessment of Technical Expertise (OPERATE) tool. Vascular surgeons with varying experiences performed open AAA repair in a standardised simulation based setting. All procedures were video recorded with the faces anonymised and scored independently by three experts in a mutual blinded setup. The Angoff standard setting method was used to establish a credible pass/fail score. RESULTS: Sixteen novices and nine experienced open vascular surgeons were enrolled. The OPERATE tool achieved high internal consistency (Cronbach's alpha .92) and inter-rater reliability (Cronbach's alpha .95) and was able to differentiate novices and experienced surgeons with mean scores (higher score is better) of 13.4 ± 12 and 25.6 ± 6, respectively (p = .01). The pass/fail score was set high (27.7). One novice passed the test while six experienced surgeons failed. CONCLUSION: Validity evidence was established for the newly developed OPERATE tool and was able to differentiate between novices and experienced surgeons providing a good argument that this tool can be used for both formative and summative assessment in a simulation based environment. The high pass/fail score emphasises the need for novices to train in a simulation based environment up to a certain level of competency before apprenticeship training in the clinical environment under the tutelage of a supervisor. Familiarisation with the simulation equipment must be ensured before performance is assessed as reflected by the low scores in the experienced group's first attempt.

Diagnostic methods for measurement of peripheral blood flow during exercise in patients with type 2 diabetes and peripheral artery disease: a systematic review.

INTRODUCTION: Measurement of systolic ankle and to some extent toe pressure in patients suffering from combined type 2 diabetes mellitus (T2DM) and peripheral arterial disease (PAD) face several obstacles due to complex changes in the vascular bed. The aim of this review was to address the current literature on blood flow during exercise in patients with PAD and T2DM and assess the feasibility of these methods to diagnose and grade arterial insufficiency. EVIDENCE ACQUISITION: A systematic review of the PubMed and EMBASE databases, supplemented by hand searching was performed according to PRISMA guidelines. Clinical studies evaluating methods to investigate peripheral blood flow in patients with PAD and T2DM during exercise were included. EVIDENCE SYNTHESIS: In total nine eligible studies consisting of 1105 non-diabetic PAD patients, 336 diabetic PAD patients, 161 diabetic patients without PAD and 69 healthy controls were included in the review. Near-infrared spectroscopy (NIRS) was described in three studies, transcutaneous oxygen pressure measurement (TcpO2) in two and the following methods described in single studies: thermodilution, contrast enhanced ultrasound (CEUS), scintigraphy and TcpO2 in combination with ultrasound. These studies shows that patients with PAD and T2DM compared with patients with only PAD suffers different atherosclerotic lesions characterised by increased arterial stiffness and microcirculation abnormalities, not well differentiated by pressure measurement alone. Investigating patients with PAD and T2DM during exercise reveals that NIRS, TcpO2, CEUS, and scintigraphy have distinct advantages over ankle and toe-pressure. CONCLUSIONS: Using methods like NIRS, TcpO2, CEUS and scintigraphy, peripheral blood flow during exercise can be measured at a detailed level and potentially improve future severity grading in patients with combined T2DM and PAD.