(1) At most, only four or five patients are seen each year by a major vascular centre; (2) aortic aneurysms are found in 37 per cent and bilateral PAAs in 50 per cent of patients; (3) more than 95 per cent of patients are men with a mean age of 65 years and 45 per cent have hypertension; (4) approximately one-third of patients are asymptomatic at the time of initial diagnosis; (5) the risk of ischaemic complications after conservative follow-up varies from 8 to 100 per cent (mean 36 per cent), depending on the selection of patients and duration of follow-up; (6) elective surgical reconstruction is recommended for all asymptomatic aneurysms; (7) 5-year graft patency rates after surgical repair range from 29 to 100 per cent, with 5-year limb salvage ranging from 75 to 98 per cent; (8) patient survival rates at 5 and 10 years are 70 and 44 per cent respectively; (9) lifelong, careful patient surveillance is essential to detect and treat new aneurysms at other sites.

In a retrospective study 42 patients with asymptomatic popliteal artery aneurysm were followed without surgery to identify variables predicting the risk of complications. The mean aneurysm size was 3.1 cm. Abnormal ankle pulses were found in 18 of the 42 limbs in which an asymptomatic popliteal aneurysm was present. Follow-up was complete (mean 6.2 years). Twenty-five patients developed complications at a mean observation time of 18 months. As a result three lost the limb, eight had claudication, two needed a fasciotomy and one had a peroneal nerve palsy. The cumulative risk of developing complications during follow-up was 24 per cent at 1 year, rising to 68 per cent at 5 years. Patients with absent ankle pulses and those already operated on for abdominal aortic aneurysm proved to be especially at risk. Patient survival appeared to be normal for the period of observation. It is concluded that asymptomatic aneurysm of the popliteal artery is a potentially dangerous lesion that may justify elective surgery; it is possible to select those at highest risk.

(1) At most, only four or five patients are seen each year by a major vascular centre; (2) aortic aneurysms are found in 37 per cent and bilateral PAAs in 50 per cent of patients; (3) more than 95 per cent of patients are men with a mean age of 65 years and 45 per cent have hypertension; (4) approximately one-third of patients are asymptomatic at the time of initial diagnosis; (5) the risk of ischaemic complications after conservative follow-up varies from 8 to 100 per cent (mean 36 per cent), depending on the selection of patients and duration of follow-up; (6) elective surgical reconstruction is recommended for all asymptomatic aneurysms; (7) 5-year graft patency rates after surgical repair range from 29 to 100 per cent, with 5-year limb salvage ranging from 75 to 98 per cent; (8) patient survival rates at 5 and 10 years are 70 and 44 per cent respectively; (9) lifelong, careful patient surveillance is essential to detect and treat new aneurysms at other sites.

An acute rupture of a popliteal aneurysm is rare. Although the clinical presentation can be non-specific, this possibility must be especially taken into account when dealing with older male patients presenting with signs and symptoms of generalised atherosclerosis and non-specific pain in the popliteal region.

Major vascular events and additional interventions are common and serious in claudicants. However, it is possible to select low-risk patients in which peripheral bypass surgery is justified.