Haemodynamic Changes in Femoral-popliteal Bypass Grafts With the Use of Neuromuscular Electrical Stimulation.
试验速览
- 阶段
- 不适用
- 状态
- 撤回
- 试验地点
- 2
- 主要终点
- Change in volume flow rate (VFR).
研究概览
简要总结
The muscles of the leg require a regular supply of oxygen and nutrients. This is supplied by blood carried by a network of large blood vessels known as arteries. Gradually, these arteries can become narrowed or blocked by a build-up of fatty deposits. This process is known as atherosclerosis and leads to a condition called peripheral arterial disease. The restriction of blood flow caused by the blockage prevents exercising muscles getting enough oxygen and nutrients. In some people, this may lead to a painful ache in their legs when they walk, known as intermittent claudication. If the leg pain is severe, surgeons may decide to bypass this blockage using a vein taken from another part of the body, thereby improving blood flow to the foot.
Patients with a narrowing or blockage anywhere in the main artery that runs from the groin to the back of the knee may be treated with a particular type of bypass graft known as a femoral-popliteal bypass graft. However, this graft may collapse if not enough blood is flowing through it.
This study is looking to see whether a circulation booster machine, known as the REVITIVE® device, can improve the amount of blood flowing through femoral-popliteal bypass grafts. Patients with these grafts attending their usual clinic appointment in the Vascular Outpatients department at Charing Cross Hospital, London will be asked to have their leg scanned using an ultrasound machine to measure the amount of blood flowing through the graft. They will then use the REVITIVE® device for 30 minutes, before being re-scanned to see whether the device has improved blood flow. Improvements in blood flow may suggest a promising role for the device in keeping these grafts open, therefore helping them last longer and potentially reducing the leg pain associated with peripheral arterial disease.
详细描述
Within the vascular department at Charing Cross Hospital, there is an on-going NIHR-funded trial looking at the haemodynamics and clinical outcomes of patients with intermittent claudication. The aim of the study is to find out whether the neuromuscular electrical stimulation (NMES) device, REVITIVE®, can improve the time-averaged mean velocity (TAMV) and volume flow rate (VFR) through femoral-popliteal bypass grafts. Previous studies have shown that NMES can enhance arterial TAMV and VFR and have suggested the utility of NMES in the management of intermittent claudication, critical limb ischaemia and limb salvage. By enhancing arterial TAMV and VFR, NMES has been said to mimic the effect of exercise in the redistribution of arterial circulation. This is achieved through activation of the calf muscle pump, which empties the venous bed, thus increasing the pressure difference between the venous and arterial system. This creates a hyperaemic response in which there is faster arterial inflow against a lower venous back pressure. NMES could also enhance TAMV and VFR in femoral-popliteal bypass grafts which could, in turn, improve graft inflow and thus prolong patency.
If TAMV and VFR are enhanced, this may suggest that the REVITIVE® device could help prolong the patency of femoral-popliteal bypass grafts and be given to patients with these grafts to be used for 30 minutes daily as part of their management.
Methods
A Phillips (Guildford, UK) EPIQ 7 ultrasound machine and L12-5 transducer will be used to measure graft flow parameters using a pre-set optimised vascular protocol. A Phillips (Guildford, UK) EPIQ 7 ultrasound machine will be used as these are used frequently by Clinical Vascular Scientists in the Vascular Outpatients department to scan patients. An L12-5 transducer will be used as the proximal section of the femoral-popliteal graft will be scanned, which is a superficial structure and therefore a probe that is designed for imaging superficial structures should be used to obtain the best possible image resolution. Real-time gated Doppler superimposed on B-mode imaging will be used in the evaluation of flow and processed using automated waveform enveloping duplex software, as previously described.
First ultrasound scan: Patients will be called into a vascular ultrasound scanning room where a Clinical Vascular Scientist will ask the patient to rest for 10 minutes on an examination couch. A region of the femoral-popliteal bypass graft 3-5 cm from the saphenofemoral junction, or as proximal as possible depending on the patient's body habitus, will be identified and the position of the probe marked on the skin for consistency of repeat measurements. This method for maintaining consistency was chosen as it proved successful in similar studies. When obtaining measurements, the patient will be positioned semi-recumbent with the leg externally rotated at the hip to 35-40 degrees and flexed at the knee according to their comfort. Baseline measurements of TAMV and VFR (calculated using built-in software) will be taken and recorded via a 15-second electronic screenshot. All diameter measurements will be obtained by placing electronic callipers on the inner edge to inner edge of the graft to obtain the luminal diameter and to improve reliability of this measurement. Where indicated by reliability measurements (see below), a predetermined number of consecutive measurements of TAMV and VFR will be taken and an average calculated later. PV of the greatest waveform amplitude of each screenshot will be analysed at a later date using standard techniques.
研究设计
- 研究类型
- Interventional
- 分配方式
- Na
- 干预模型
- Single Group
- 主要目的
- Basic Science
- 盲法
- None
入排标准
- 年龄范围
- 18 Years 至 —（Adult, Older Adult）
- 性别
- All
- 接受健康志愿者
- 否
入选标准
- •Have a confirmed diagnosis of peripheral arterial disease (PAD);
- •Have undergone revascularisation surgery via a vein femoral-popliteal bypass graft;
- •Are willing to participate and are able to provide written informed consent;
- •Are aged over 18 years;
- •Agree to attend at least one of their usual clinic appointments at the Vascular Outpatients department at Charing Cross Hospital, London before 13th April 2020 (project deadline for the student is Monday 11th May 2020);
- •Have a body mass index (BMI) between 17 and 30 kg/m2.
排除标准
- •Do not have a diagnosis of PAD;
- •Have not had revascularisation surgery;
- •Have had revascularisation surgery via an artificial femoral-popliteal bypass graft;
- •Are fitted with an electronic implanted device;
- •Are being treated for (or have symptoms of) a deep vein thrombosis (DVT);
- •Are pregnant.
结局指标
主要结局
Change in volume flow rate (VFR).
时间窗: 1 to 3 hours
Change in VFR in femoral-popliteal bypass grafts after use of the NMES device.
Change in peak systolic velocity (PSV).
时间窗: 1 to 3 hours
Change in PSV in femoral-popliteal bypass grafts after use of the NMES device.
Change in time-averaged mean velocity (TAMV).
时间窗: 1 to 3 hours
Change in TAMV in femoral-popliteal bypass grafts after use of the NMES device.
次要结局
- Inter-user reliability measurements volume flow rate (VFR).(1 to 3 hours)
- Intra-subject reliability measurements of volume flow rate (VFR).(1 to 3 hours)
- Intra-subject reliability measurements of time-averaged mean velocity (TAMV).(1 to 3 hours)
- Intra-subject reliability measurements of peak systolic velocity (PSV).(1 to 3 hours)
- Inter-user reliability measurements of time-averaged mean velocity (TAMV).(1 to 3 hours)
- Inter-user reliability measurements of peak systolic velocity (PSV).(1 to 3 hours)