Intraoperative venous dilation and subsequent development of deep vein thrombosis in patients undergoing total hip or knee replacement

This patient study was based on the observation of characteristic intimal lesions in jugular and femoral veins removed from dogs a few hours following total hip replacement. The lesions, small localized intimal tears, suggested that smooth muscle and connective tissue, might have dilated beyond the ability of intima to accommodate. Intraoperative venous dilation correlated with the incidence of intimal lesions. It was postulated that surgical trauma resulted in circulating vasoactive substances which caused venous dilation and that dilation of smooth muscle and connective tissue beyond the yield point of intima resulted in intimal rupture. Similar intraoperative dilation and lesions, in patients might predispose to development of deep vein thrombosis (DVT). Total hip (THR) and total knee (TKR) replacement patients were selected for study because: (a) of the high incidence of DVT and (b) blood circulation is present in THR but not in TKR patients during operation. Ultrasound was used to monitor cephalic vein diameter during the perioperative period. Development of DVT postoperatively was compared with intraoperative venous dilation. In THR patients, intraoperative venous dilation ranged from 6%–56%. One of nine patients with dilation ≤ 17% developed DVT while 12 patients with dilation of ≥22% developed DVT, giving a correct prediction of 95%. Of four patients in the intermediate range (19%, 20%), two developed DVT and two did not. The sharp demarcation was to be expected because of abrupt rupture of viscoelastic material when the critical point of elongation is exceeded. In TKR patients (with no intraoperative circulation in the operated leg), nine of 11 developed DVT, all in the operated leg, but only one had venous dilation ≥ 22%. We suggest that intraoperative ultrasound monitoring promises to identify susceptible patients, making it possible to target prophylaxis to them.