Continuous flow left ventricular assist device related aortic root thrombosis complicated by left main coronary artery occlusion

From the Brigham and Women’s Hospital Heart and Vascular Center and Harvard Medical School, Boston, MA Thrombosis and thromboembolism are an increasingly recognized source of early postoperative morbidity following institution of mechanical circulatory support. We report an unusual case of aortic root thrombus occluding the left main coronary artery four days after implantation of an axial continuous flow HeartMate II (Thoratec, Pleasonton, CA USA) left ventricular assist device (LVAD). A 48-year old man with refractory, inotrope-dependent heart failure due to idiopathic dilated cardiomyopathy underwent elective LVAD implantation as a bridge to cardiac transplantation. Aspirin 325mg was initiated within 24 hours of surgery and unfractionated intravenous heparin (target partial thromboplastin time 60-80 seconds) was started within 36 hours. Lactate dehydrogenase was measured at 502 U/L. On the fourth postoperative day, an echocardiogram was performed for LVAD speed and flow optimization. The pump speed was decreased from 9600 RPM to 8600 RPM until intermittent aortic valve opening was achieved; immediately after the pump speed was reduced, the patient had abrupt onset of nausea, dyspnea and left shoulder discomfort. An electrocardiogram revealed 4mm ST-segment elevations in leads V2-V6 consistent with anterior myocardial injury. The patient underwent emergent coronary angiography, which revealed thrombotic obstruction of the terminal portion of the left anterior descending (LAD) coronary artery, but no proximal disease. Root aortography revealed a thrombus in the left coronary cusp obstructing the left main coronary artery ostium (Figure 1). Transesophageal echocardiography confirmed the presence of a thrombus in the left coronary cusp with dense spontaneous echo contrast noted throughout the aortic root (Figure 2). A guide catheter was left engaged in the left main coronary artery to protect against recurrent Figure 1 Contrast injection in the aortic root revealing thrombus in the left coronary cusp partially obstructing the left main coronary artery.