Interventional
vascular techniques
By
selective arterial cannulation it is possible to deliver a high local dose of
a chemotherapeutic agent to the feeding vessels of a tumour. This technique
has been used with success for liver turnouts, particular hepatocellular
carcinoma, metastatic colorectal cancer and ocular melanoma.
There
has been a resurgence of interest in the potential of low dose intra-arterial
infusion of thrombolytic agents in peripheral arterial thromboembolic
occlusion. The choice of therapy between surgical embolectomy and thrombolysis
is controversial.
In
patients with recurrent or threatened pulmonary embolisation from lower
extremity or pelvic thrombus, inferior vena caval filters may be inserted
percutaneously, from either a femoral or jugular approach to prevent the
passage of a major embolus. A femoral approach is appropriate if the thrombus
does not extend proximally into the inferior vena cava and if the
contralateral femoral and pelvic veins are patent. Otherwise, a jugular
approach is indicated, assuming the superior vena cava is patent.
Management of vascular obstruction
Percutaneous
transluminal angioplasty
Indications include:
• peripheral vascular disease with relatively short
occlusions (10—15 cm in length);
• ischaemic heart disease with coronary artery stenosis;
• hypertension or chronic renal failure with renal
transplant artery stenosis;
• mesenteric/coeliac artery stenosis.
The
technical success rate for femoral and popliteal angioplasty is between 85
and 95
per cent for stenoses with
a 20—70 per cent patency rate at 5
years (Fig.
2.41). Complications
include local haemorrhage and haematoma, false aneurysm formation at the
puncture site, subintimal dissection and arterial perforation. The incidence
of peripheral
Transjugular intrahepatic porto-systemic shunt
(TIPSS)
A
particular use of expanding metal stents has been in the development of TIPSS,
which involves the percutaneous creation of a communication between the portal
and hepatic venous systems for the relief of portal hypertension (Fig.
2.42).
This procedure was first performed by Richter in 1988 and is now firmly
established as an alternative to surgery in patients with recurrent variceal
bleeding who are resistant to sclerotherapy or endoscopic banding. The
technical success rate is over 90 per cent. The major complication is hepatic
encephalopathy which can develop following the procedure. Shunt occlusion may
develop, usually as a result of intimal hyperplasia. This may require
re-intervention with balloon dilatation or a second stent insertion.
Therapeutic embolisation
Deliberate vascular embolisation with the aim of occluding a vessel can be achieved using a variety of different materials including gelatin, sponge fragments, polyvinyl alcohol foam particles (PVA) and spiral metal coils.
Arterial
embolisation may be used in the treatment of:
• acute haemorrhage;
• tumour therapy;
• arterio-venous malformations;
• hypersplenism;
• priaprism.
Venous
embolisation is used for treatment of:
• gastro-oesophageal varices;
• testicular varicocele.