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Background information
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Background Information
1) Stroke and TIA
Patients with symptomatic 70% carotid stenosis have a 25% risk of disabling stroke within three years.
Patients with transient ischaemic attacks (TIA) or cerebrovascular attack (CVA) should have a carotid investigation within four weeks of initial symptoms.
An ultrasound diagnosed symptomatic 70% stenosis should be operated on within one month.
Stroke accounts for 4% of NHS resources1. Rehabilitation costs the NHS £10,000 to £13,000 per patient in the first year following a stroke2.
Delayed diagnosis increases the risk of litigation, which in the case of stroke would be extremely costly.
Preventing just eight strokes per year by early diagnosis of carotid disease will pay for a full-time IVS vascular service.
References
1. Wade DT. Stroke (acute cerebrovascular disease) In: Stevens-A, Raferty-J, eds Health Care Needs Assessment. Vol. 1 Oxford: Radicliffe Medial Press; 1994:111-255
2. Costs of Stroke Care to Handicap Levels and Stroke Subtype’Cerebrovasc Dis. 2004; 17(2-3):134-142 & ‘Cost of stroke in Australia form a societal perspective:results form the North East Melbourne Stroke Incidence Study (NEMESIS)’ Stroke 2001 Oct;32(a0):2409-16
2) Deep vein thrombosis (DVT)
Ultrasound is the most accurate and cost effective way to diagnose calf and thigh DVT1.
Early diagnosis and treatment reduces the risk of pulmonary embolus (PE) and post thrombotic leg symptoms. Frequency of PE is 52 to 79.4%2.
Recently a Manchester NHS hospital paid a legal claim of over £130,000 for not diagnosing a DVT, this would cover the entire cost of a full time IVS service for two years.
References
1.Safety of a single duplex scan to exclude deep venous thrombosis. Wolf B, Nichols D M, Duncan J L. Br J Surg 2000; 87: 1525-1528.
2. Mostbeck A, Ludwig Boltzman-Institut fur Niklearmedizin, Wein. Incidence of pulmonary embolism in venous thrombosis. Wein-Med-Wochenschr. 1999; 149(2-4): 72-5
3) Aneurysm screening
Aneurysms in men should only be repaired if the diameter exceeds 5.5cm1.
Ultrasound is an accurate way to identify abdominal aortic aneurysms and determine the time for intervention2.
Screening men for abdominal aortic aneurysms is cost effective and reduces mortality by over 50%3.
Recommend surveillance program in patients with aneurysms
| Men |
Women |
Review times |
| 3.0 – 4.0cm | 3.0 – 4.0 cm | Annual |
| 4.0 – 4.9cm | 4.0 – 4.5cm | Six monthly |
| 5.0 – 5.5cm | 4.5 – 5.0cm | 3 monthly |
| >5.5cm | >5.0cm | CT scan and ? repair |
References
1. Immediate repair compared with surveillance of small abdominal aortic aneurysms. Lederle F A, Wilson S E, Johnson G R et al. N Eng J Med 2002; 346: 1437-1444.
2. Mortality results for randomised controlled trial of early elective surgery or ultrasonographic surveillance for small abdominal aortic aneurysms. The UK Small Aneurysm Trial Participants. Lancet 1998; 352: 1649-1655.
3. The Multicentre Aneurysm Screening Study (MASS) into the effect of abdominal aortic aneurysm screening on mortality in men: a randomised controlled trial. The Multicentre Aneurysm Screening Study Group. Lancet 2002; 360: 1531-1539.
4) Varicose vein surgery
Duplex ultrasound should be routine before varicose vein surgery. Clinical and hand held Doppler assessment of varicose veins are unreliable when compared to Duplex ultrasound1.
Precise diagnosis and treatment of varicose veins, guided by simple Doppler and Duplex imaging, reduces the risk of recurrence from over 40% to below 5%2.
References
1. The use of routine duplex scanning in the assessment of varicose veins. Wills V, Moylan D, Chambers J. Aust NZ J Surg 1998; 68: 41-44.
2. Surgicares recurrence rate has been reduced to less than 5% compared a national recurrence rate of up to 60%. www.surgicare.co.uk
5) Peripheral artery assessment
Over 4% of patients with symptomatic lower limb arterial disease will have an amputation within 5 years1.
A third of patients with symptomatic disease will die within 5 years1
60% from coronary artery disease
15% from stroke
10% will develop an abdominal aortic aneurysm.
References
1. www.medical–library.org
6) Vein mapping for use in lower limb and coronary artery bypass grafts (CABG)
1.Saphenous vein mapping by duplex ultrasound is reliable, marking the vein, checking patency and measuring vein diameter prior to harvest. This reduces unnecessary exploration and the time to harvest vein for grafting.
2. Radial artery may be used as a conduit for CABG and has a patency rate of 91.6% at 5 years1.
Ultrasound can be used to assess the suitability of the radial artery but also ensure the ulnar artery adequately supplies the arm/hand before removing the radial artery.
References
1. Acar-C et al. department of Cardiovascular surgery, hospital Bichat and Broussais, Paris, France. The radial artery for coronary artery bypass grafting: clinical and angiographic results at five years. J-Thorac-Cardiovasc-Surg. 1998 Dec; 116(6):981-9
7) Vein graft surveillance
Graft surveillance has a proven benefit and reduces costs to the NHS from re-operation and limb loss1.
Risk of graft stenosis reduces after one year but there is still a 10-20% risk of developing a late stenosis. Graft surveillance should continue indefinitely2.
References
1. Dunlop-P; Hartsthorne-T; Bolia-A; Bell-PR; London-NJ. Department of Surgery, Leicester Royal Infirmary, UK. The long term outcome of infrainguinal vein graft surveillance. Eur-J-Vasc-Endovasc- Surg. 1995 Oct; 10(3):352-5
2. McCarthy-MJ; Olojugba-D; Loftus-IM; Naylor-AR; Bell-PR; London-NJ. Department of Surgery, Leicester Royal Infirmary, UK. Lower limb surveillance following autologus vein bypass should be life long. Br-J-Surg. 1998 Oct; 85(10):1369-72
8) Transcranial Doppler (TCD)
TCD may be used to measure blood flow in the brain. It can be used to continuously monitor the middle cerebral artery flow with clear criteria for shunting and emboli detection during and after carotid surgery.
Spontaneous cerebral emboli, detected by TCD, are associated with a risk of stroke in patients with carotid disease.
New evidence suggests that cerebral emboli may be a preventable cause of both Alzheimers disease and vascular dementia. If spontaneous cerebral emboli are detected in otherwise healthy people, there may be a risk of dementia that could be prevented by simple drug therapy.
9) Patent foramen ovale (PFO) and paradoxical embolism
Venous to arterial shunts (v-aCS) are a frequent cause of stroke in young people and are common in patients with both Alzhimers disease and vascular dementia.
TCD has a 100% sensitivity and 82% specificity for identifying PFO. All patients with v-aCS are at risk of paradoxical embolism which may cause stroke, gut or other tissue ischaemia.
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