ANGIOPLASTY OR BYPASS? 261
(a) (b) (c) (d)
Figure 21.3 Arterialisation of vein grafts; a femoro-tibial vein graft in an insulin-dependent diabetic patient imaged 12 years after reconstruction, when angioplasty for stenosis was required for the third time: (a) proximal anastomosis to the common femoral artery; (b) aneurysmal dilatation and diffuse irregularity at mid-thigh level; (c) the atherosclerotic vein graft crosses the knee in a subcutaneous tunnel; (d) distal anastomosis to the atherosclerotic upper anterior tibial artery.
from centres with an interest in distal bypass, irrespective of inflow source or outflow vessel.38 Beyond this time, survival declines more rapidly than graft failure. Good-quality vein grafts are capable of indefinite survival, as is seen when they have to be constructed in children. However, arterialised vein grafts in atherosclerotic hosts are eventually susceptible to the same degenerative processes as arteries (Figure 21.3).
ANGIOPLASTY OR BYPASS?
With increasing experience, these treatment options are coming to be regarded as complemen- tary, rather than as competing alternatives.
Attempts at conducting randomised prospective comparisons have been limited by the difficulty of recruiting cases in whom the choice of one or other method is not dictated by clinical or angiographic imperatives.
When the endovascular option is available, it will usually be preferred on grounds of safety, low morbidity and economy.
Most vascular surgical units have seen at least a 50% reduction in the annual number of infrainguinal bypass operations performed since the introduction of
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262 PERIPHERAL VASCULAR DISEASE AND RECONSTRUCTION
endovascular interventions for CLI. The relative lack of durability of angioplasty is offset by its repeatability and the limited life expectancy of the subjects. These trends have meant that the rump of patients being considered for surgical bypass are likely to present complex challenges. The criteria influencing the choice of angioplasty or bypass are summarised below.
Surgical bypass Angioplasty
Relative considerations SFA occlusion: flush origin or >20cm Short stenoses, occlusions <20 cm Advanced ischaemic necrosis Venous or neuropathic ulceration ABPI <0.5 ABPI >0.5 Life expectancy > 2 years Life expectancy <2 years Combined inflow and CFA disease Aorto-iliacs dilatable, CFA clear Inframalleolar occlusion Absolute indications for surgery Failed angioplasty Acute ischaemia Aneurysmal disease Heavy calcification
CONCLUSIONS Although developments in endovascular technique have reduced the volume of patients requir- ing bypass reconstruction for CLI, those that are ineligible or unsuitable for angioplasty, many of whom have diabetes, present complex challenges to vascular surgeons. In order to achieve optimal limb salvage with minimal morbidity, the surgical team requires multidisciplinary support and must have access to a wide range of skills and techniques. When revascularisation proves impossible, an equally positive approach to palliation, amputation and rehabilitation is necessary.