Venous haemodynamics and the occurrence of leg oedema in patients with popliteal aneurysm.

OBJECTIVES: To see whether popliteal aneurysms cause venous obstruction and to investigate leg oedema and DVT following repair.

DESIGN: Prospective open clinical study.

SETTING: University Department of Surgery.

MATERIALS: 8 patients undergoing popliteal aneurysm repair in 9 legs (1 bilateral repair).

CHIEF OUTCOME MEASURES: CT and plethysmographic evidence of vein compression, the occurrence of postoperative leg oedema and phlebographic evidence of deep venous thrombosis (DVT).

MAIN RESULTS: Preoperative CT investigation showed that the aneurysm compressed the popliteal vein in 6/9 limbs where surgery was planned and in 9/10 limbs with popliteal aneurysms (patent or occluded) of > 2 cm diameter (p < 0.01). However, on the CT image, increased collateral network could be observed and most patients had normal venous drainage prior to operation as assessed by air plethysmography. Postoperatively, leg volume was measured by the formula of a truncated cone. Following vascular reconstruction, leg volume increased by 23%. Except for one patient with a confirmed DVT preoperatively, postoperative venous congestion and DVT was not observed in the operated leg as assessed by phlebography and plethysmography.

CONCLUSIONS: Popliteal artery aneurysms "2 cm diameter usually compress and dislocate the popliteal vein prior to operation. However, sufficient venous drainage is maintained, possibly because of an increased collateral venous network. Disruption of lymph channels with secondary lymphoedema is probably the most important mechanism behind the leg swelling observed in patients following popliteal aneurysm repair.