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Setting Up a Vascular Collaboration Research Project. Sohail Choksy Consultant Surgeon, CHUFT Prof Ralph Beneke Essex University. Atherosclerosis affects all arterial beds. Cerebrovascular disease Ischaemic stroke Transient Ischaemic Attack (TIA). Cardiovascular disease
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Setting Up a Vascular Collaboration Research Project Sohail Choksy Consultant Surgeon, CHUFT Prof Ralph Beneke Essex University
Atherosclerosis affects all arterial beds • Cerebrovascular disease • Ischaemic stroke • Transient Ischaemic Attack (TIA) • Cardiovascular disease • Myocardial Infarction (MI) • Angina (stable/unstable) • Peripheral arterial disease (PAD) • Intermittent claudication • Pain on walking • Severe limb ischaemia • Rest pain • Gangrene, necrosis
Prevalance and risk factors • 5% 55-74 y Claudication, further 8% asymptomatic • Risk factors • Increasing age (>50 yrs old) • Diabetes 2-3X • Smoking 2X • Hypertension 2.5-4X • Hyperlipidaemia 2X • Ethnicity, gender, homocysteinaemia, previous MI Belch et al Arch Int Med. 2003;163: 884-892
Peripheral Arterial Disease (PAD) • Symptomatology • Asymptomatic • Intermittent claudication • Critical limb ischaemia
SymptomatologyIntermittent claudication • “Claudere” to limp • Pain is muscular and cramp-like • Absent at rest, brought on by exercise • Pain relieved within a few minutes of stopping exercise • Pain occurs in muscle group downstream to the diseased artery • Affects walking speed normal 3mph, claudicant 1-2mph
ABPI Diagnosis of PAD Clinical history Physical examination Ankle Brachial Pressure Index (ABPI) Exercise test Duplex ultrasonography Angiography
Symptomatology:Critical limb ischaemia Definition • Inadequate arterial blood flow for the metabolic needs of the tissues at rest Symptoms • Rest pain • Ulcers/gangrene • Doppler pressures • 50mm Hg at ankle • 30 mm Hg at toes • Quality of life similar to terminal cancer
Reduce cardiovascular risk Treating Peripheral arterial disease Reduce symptoms and improve quality of life Exercise Therapy Pharmacological treatment Radiological or surgical treatment • Lifestyle modification • Smoking cessation • Exercise • Diet, weight reduction • Secondary prevention • Antiplatelet • Statins (lipid control) • BP control, diabetic control
Exercise Therapy • Little evidence that exercise advice is effective • Supervised exercise therapy is associated with • Improvement in max walking time (5.12 minutes (95% confidence interval (CI) 4.51 to 5.72;) • pain-free walking distance 82.19 metres (95% CI 71.73 to 92.65) • Max walking distance of 113.20 metres (95% CI 94.96 to 131.43) • No improvement in ABPI Cochrane Database Syst Rev. 2008 Oct 8;(4):CD000990. Exercise for intermittent claudication. Watson L, Ellis B, Leng GC.
Mechanism of improvement in Claudication • Mechanism of improvement of walking distance in claudication unknown • Local or systemic effect? • Possible explanations: • Improved blood flow • Altered gait • Improved extraction of oxygen by muscles i.e. Metabolic • Pain tolerance • Improved cardiovascular fitness
Research Questions • What is/are the dominant mechanism(s) by which exercise causes an improvement in walking performance in claudicants? • How can we tailor exercise to optimise improvement?
Setting up a research collaboration • Project in drawing board stage in “evolution” • Collaborators: • CHUNT: Sohail Choksy, Adam Howard, Chris Backhouse and Emma Raynar • Essex University: R Beneke, C Cooper, A Wittekind, MJD Taylor, RM Leithäuser, T Cudmore • Multidisciplinary project combining expertises in Sports and Exercise Medicine, Vascular Surgery, Patho- and Exercise Physiology, Biomechanics, Biomedical Sciences and Sport Science Support
Subjects • Patients with stable intermittent claudication whose symptoms do not warrant surgical or radiological revascularisation • Diagnosis based on history and ABPI<0.9 • Exclude patients on drugs for claudication e.g. Cilostazol • No other cause limiting exertion e.g. COPD and CHD • Patients recruited into Colchester Vascular Rehabilitation Programme
Vascular Rehabilitation programme • Run by Vascular Nurse Specialist (Emma Rayner) and 2 physiotherapists • Two one hour sessions per week • 8 week course with assessments at beginning and end of course • Brief warm up, general stretch and shake! • Then rotate around 10 stations which are aimed at improving general fitness and working calf muscle. • All stations timed for 3 minutes then on to next one.
Exercise Regimen • Stations are • 1 Treadmill (speed and gradient adjusted according to pt, aim to bring on claudication to level 3) • 2 Trampette ( heel raises on trampette) • 3 Toe walking • 4 Static bike • 5 Round wobble board (move board in circle on floor) • 6 Theraband ( around foot and move foot up and down to exercise calf) • 7 Step ups • 8 Square wobble board ( against bars, they have to wobble it back and forwards) • 9 Arm raises ( holding large ball) • 10 Sitting and standing from chair.
Study Design: Pilot Study • Initial pilot study to gather preliminary data to apply for a grant application • Simple observational study using current established exercise regimen • Aim to answer: • How is the extent of lower limb ischemia associated with claudication pain and temporal and spatial gait measures during self paced ambulation? • How do subsequent exercise interventions affect exercise intensity and exercise induced effort and pain sensations?
Study Design: Pilot Study • Assess maximum walking distance on site at baseline and completion of programme • Flat surface, not on treadmill • Steps recorded on 2 cameras for gait analysis • Muscle ischaemia: Near infra red spectroscopy (NIRS) to assess oxygen saturation of calf musculature in affected leg • Effort monitoring and pain scale • Heart rate and spirometry
NIRS Gardner et al J Vasc Surg. 2008 Sep;48(3):644-9
Study Design During exercise training monitoring of: • What was really done • Heart rate • NIRS of affected leg • pain scale monitoring • Overall effort monitoring
The Future • Larger study comparing the effect of exercise in claudicants Vs age matched controls on muscle ischaemia, gait analysis, pain perception and exercise intensity • Develop novel exercises which optimise performance in claudicants • Setting up a research infrastructure will create further potential avenues of research • Monitoring the effect of pharmacological agents on exercise performance e.g. Cilostazol and Pentoxifylline • Monitoring effect of novel methods to improve muscle perfusion e.g. Calf compression and electrical muscle stimulation