Background This study was undertaken to expand the understanding of ultrasound-guided compression repair (UGCR) of postcatheterization femoral artery injuries.Methods and Results In a series of 62 patients with pseudoaneurysms (n=53) or arteriovenous (AV) fistulas (n=9), UGCR was performed as a nonsurgical method in the treatment of postcatheterization femoral artery injuries. When the communicating channel could be visualized (43 cases), pressure was focused on it; otherwise (10 cases) the extraluminal cavity itself was compressed. In 45 cases, the elimination of flow in the pseudoaneurysm and/or the communicating channel could be achieved only with simultaneous temporary complete occlusion of the femoral artery. UGCR was successfully performed in 25 of 27 cases of false aneurysms (93%) in patients without anticoagulation and in 14 of 26 patients (54%) on anticoagulants. Three of 9 AV fistulas could be repaired by this method. No apparent correlation could be found between the therapeutic success and the size of the pseudoaneurysm or the age of the lesion.Conclusions In patients on anticoagulants and in patients with AV fistulas, the detection of a communicating channel that could be obliterated by direct mechanical compression was discerned as a discriminant factor of success. (Circulation. 1994;90:1861-1865.)