Rapid Resolution of Pulmonary Thromboemboli

To the Editor:—  An appreciation of the dynamic interplay which exists between thrombus formation, anticoagulant therapy, and natural fibrinolysis appears to be lacking in the excellent article by Fred et al 196:1137, 1966).The authors disclaimed knowledge of the mechanism of embolus dissolution, even though natural fibrinolysis was almost certainly responsible.They assigned "no role" to anticoagulant therapy in the unexpectedly rapid dissolution of pulmonary emboli in man, even though six of their seven patients received such. Because one patient did not receive anticoagulant therapy, there is no proof that this therapy played no role in the other six cases. The opposite conclusion, if any, is warranted.The authors cited Sabiston's first case report (Ann Surg160:575, 1964) showing resolution of a pulmonary thromboembolus in eight weeks. But they failed to cite Sabiston's second report (J Thorac Cardiov Surg50:339, 1965) in which he documented a complete