Coronary thromboembolism (CE) is a rare cause of prosthetic valve derived complications. This study investigates the diagnosis and treatment strategies for non-ST elevation acute coronary syndrome (NSTEACS) in patients with prosthetic heart valves. Forty-eight NSTEACS patients with prosthetic heart valves (mitra1:27; aortic:14; mitral+aortic:7) were included in this study. All patients underwent transthoracic and transesophageal echocardiographic examination and coronary angiography. Normal coronary angiographic findings, or visible trombus in one of the coronary arteries, international normalized ratio <2, concomitant prosthetic valve thrombosis (PVT) and absence of multivessel atherosclerotic disease favored CE rather than atherothrombosis. Thrombolytic therapy (TT) with low-dose slow-infusion of tissue type plasminogen activator was used in patients with suspected CE and/or PVT. Coronary angiography demonstrated normal coronary arteries in 26 patients, CE in 16 patients and coronary atherosclerosis in 6 patients. Trans esophageal echocardiography revealed obstructive PVT in 9 and nonobstructive PVT in 28 patients whereas 11 patients had normally functioning prostheses. TT was administered to 24 patients with PVT and/or CE. In these patients, TT was successful in 19 patients, partially successful in 4 patients and failed in 1 patient. In conclusion, NSTEACS in patients with prosthetic heart valves is more likely to be associated with PVT derived CE rather than atherosclerosis. TT with low-dose slow infusion of type plasminogen activator has proved its efficacy and safety in patients with CE and/or PVT. (C) 2018 Elsevier Inc. All rights reserved.