Catheterization and Cardiovascular Diagnosis 15:247-251 (1988) Prolonged Selective Urokinase Infusion in Totally Occluded Coronary Arteries and Bypass Grafts: zyx Two Case Reports Louis McKeever, MD, Joseph Hartmann, MD, Vincent Bufalino, MD, Joseph Marek, MD, Alan Brown, MD,Mark Goodwin, MD, Nicholas Stamato, MD, John Cahill, MD, Michael Colandrea, MD, and Firouz Amirparviz, MD Reports are presented demonstrating a technique for dissolving thrombus in coronary arteries and bypass grafts by using prolonged selective infusion of urokinase via an infusion wire. This allows one to pass a steerable guide wire through the culprit stenosis and perform angioplasty on a distal lesion which could not be previously seen. Key words: thrombolysis, myocardial infarction, clot lysis INTRODUCTION zyxwvutsrq line. The patient was placed on a heparin drip. Three Thrombolytic therapy is effective in lysing thrombi in the setting of acute myocardial infarction [ 1,2]. The lysis of clots in unstable angina or limited subendocardial necrosis is not widely reported in the literature zyxwvu [3,4]. The cases reported here demonstrate the presence of clot in these individuals; a technique is described of lysing the clots with a prolonged infusion of low-dose urokinase via an infusion wire inserted directly into the thrombus. Clot lysis may uncover a hidden stenotic lesion which can then be dilated with angioplasty. This management approach may obviate the risk of showering emboli into the distal vascular bed, as is sometimes seen when angio- plasty is attempted zyxwvuts [5]. CASE 1 J.S. is a 67-year-old white male who presented to the emergency room with an acute inferior wall myocardial infarction complicated by ventricular fibrillation. After successful resuscitation with defibrillation and cardiopul- monary resuscitation, intravenous streptokinase was given at a dose of 1.5 million units while the cardiac catheterization laboratory prepared to accept the patient. The electrocardiogram revealed ST segment elevation in leads 11, I11 and AVF. Coronary arteriography revealed a total occlusion of a large dominant right coronary artery distal to a large acute marginal branch (Fig. 1). The left anterior descending had nonocclusive plaques and the circumflex was normal. Because of persistent chest pain the right coronary artery occlusion was successfully opened with a 4.0 mm balloon catheter over a O.Ol&inch guide wire with residual stenosis of 10% (Fig. 2). A localized dissection possibly related to a slightly over- sized balloon was noted in the dilated segment. The chest pain resolved and ST segment elevation returned to base- zyxwv 0 1988 Alan R. Liss, Inc. hours elapsed uneventfully until nausea, vomiiing , and hematemsis occurred. Gastroenterology consultation was obtained and a diagnosis of Mallory-Weiss syndrome was made. Heparin was discontinued. Packed red blood cells were given along with fresh-frozen plasma and cryopre- cipitate which normalized coagulation parameters and stopped the bleeding. Low-dose subcutaneous heparin was started the following day but systemic anticoagula- tion was avoided. The patient was asymptomatic for the next week. On the eighth hospital day, the patient had several episodes of recurrent dyspnea and chest pain and was brought back to the catheterization laboratory. Revisualization of the right coronary artery again revealed a total occlusion but this time about 30 mm proximal to the area of pre- vious angioplasty at the level of the origin of a large acute marginal branch (Fig. 3). Collaterals were now seen filling the distal vessel retrograde. The occlusion could not be crossed with a guide wire. The etiology of the occlusion could not be certain. Coronary spasm, extensive dissection, and high coronary vascular resis- tance with poor distal visualization were all consid- ered.Experience in peripheral vessel occlusion suggested to us that regardless of the cause of obstruction, thrombus is usually present, and if lysed, can uncover an offending lesion [6]. From the Section of Cardiology, Good Samaritan Hospital, Down- ers Grove, Illinois. Received February 8, 1988; revision accepted June 20, 1988 Address reprint requests to Louis McKeever, M.D., Midwest Heart Specialists, Ltd., 2340 Highland Avenue, Suite 310, Lombard, IL 60148.