[Radioisotope studies of the spontaneous course of postoperative deep venous thrombosis].

Radiofibrinogen tests were applied to 88 surgical and urological patients with postoperative thrombosis of deep veins to establish point and time of thrombus origin and courses taken by thrombi. Most of the thrombi thus recorded had originated from venous bulges of the calf, the soleus sinus. These accounted for 83 per cent of all thrombi detected. Progress was in all cases in proximal direction, towards the popliteofemoral veins. The intraoperative phase was found to be the most dangerous juncture for the development of thrombi, with 36 per cent of all thrombi emerging on the day of surgery and another 22 per cent on the first and second postoperative days. Prophylaxis against thrombosis, therefore, should be initiated prior to surgical intervention in any case. Bilateral thrombosis was recorded from 22 cases. Sixty-one per cent of all thromboses were localised on the left side, and 81 per cent of all postoperative thromboses were clinically latent. There were six non-lethal outbreaks of pulmonary embolism and one lethal case. While the majority of calf vein thromboses was relatively harmless, the risk of pulmonary embolism increased considerably, as thrombi emerged at the level of the popliteal vein. Radioisotope investigation can be used to identify deep vein thrombosis and to figure out those patients in whom pulmonary embolism or chronic venous insufficiency may be expected to develop.