Page 81 - Medicine and Surgery

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Chapter 2: Hypertension and vascular diseases 77

paraesthesia and paralysis, which is a surgical emer- popliteal or tibial artery as the stenosis or occlu-
gency (see page 80). sion is usually long.
4 Amputation:vasculardiseasecausesmorethan90%
of all amputations; however, most vascular disease
Investigations
does not result in this. The level of amputation is
X-ray may show calcification of the vessels in the leg.

dependent on blood supply, state of joints, general
Doppler ultrasound to measure ankle systolic blood

health and age. Conservation of the knee joint is im-
pressure and assess blood flow.
portant (possible in 50%) for prosthesis and walk-
Arteriography or digital subtraction angiography al-

ing.Normallythestumpisclosedbyprimarysuture.
lows visualisation of the arterial tree.
Prognosis
Management
Five-year patency rates with femoro-distal bypass vary
Risk factors should be modified where possible, stop-

between 30 and 50%, aortoiliac reconstruction has a pa-
ping smoking in particular may prevent further dete-
tency rate of 80%. The most common cause of death
riorationandimprovessymptomsinmanycases.Care
peri-operatively and during long-term follow-up is is-
should be taken to avoid trauma. Exercise should be
chaemic heart disease.
encouraged as it improves collateral supply.
Low-dose aspirin should be used to reduce risk of

thromboembolism. Aneurysms
In most patients clinical symptoms are static or fluc-

tuate, so conservative care is sufficient. There are four Definition
options for persistently severe symptoms. Arterioscle- An aneurysm is defined as an abnormal focal dilation of
rosis in older patients is difficult to treat surgically, as an artery (see Table 2.12).
the vessels are small.
1 Sympathectomy reduces vasospasm. It is useful to
Pathophysiology
relieve rest pain in small vessel disease. It can be
An arterial aneurysm may be true or false. A true
done percutaneously with an injection of phenol.
aneurysm is enclosed by all three layers of the arte-
2 Percutaneous angioplasty is most useful for short
rial wall. A true aneurysm may be further subdivided
stenoses or occlusions in medium-sized arteries
into saccular in which there is a focal out-pouching
suchastheiliac,femoralandrenalarteries;however,
or fusiform where there is dilation of the whole cir-
as patients often present late the disease may be too
cumference of the vessel. A false (pseudo) aneurysm
widespread. A guide wire is inserted and then a bal-
occurs following penetrating trauma when there is a
loon fed over the wire and inflated within the lesion.
pulsatile haematoma, which is in contact with the ar-
Stentsareoftenusedtoimprovepatency.Complica-
terial lumen.
tions include restenosis, dissection or thrombosis.
Aneurysms tend to slowly enlarge, causing local pres-
3 Arterial reconstruction is preferably reserved for
sure problems. They may dissect and cut off blood
critical ischaemia or severely limiting intermittent
supply to tissue or rupture with resulting haemor-
claudication, because failed grafting worsens symp-
rhage.
toms and repeat surgery is very difficult. In addi-
Altered flow patterns predispose to thrombus forma-
tion, most patients have other conditions such as
tion, which may embolise to distal arteries or cause
ischaemic heart disease, diabetes and cerebrovascu-
occlusion at the site of the aneurysm.
lar disease, which increases peri- and postoperative
morbidity and mortality. Procedures include
femoro-popliteal grafts using saphenous vein, or Investigations

polytetrafluorethylene (PTFE) and CT and ultrasound scanning can demonstrate the posi-
more distal disease is best treated with a bypass tion and type of aneurysm. Arteriography or 3-D recon-

graft from the common femoral artery to the struction using MRI is used to outline the anatomy.