Detection of Non-obstructive Prosthetic Valve Thrombosis: Clinical Significance and Associations

Background- The purpose of this study was to determine how frequently prosthetic valve nonobstructive thrombosis is associated with prosthetic mitral and aortic valves and to assess their correlation with the anticoagulant status and symptoms of patients. Methods- From January 2006 to April 2007, all the patients with prosthetic heart valves who were referred for clinically-indicated transesophageal echocardiography (TEE) were evaluated for the presence of non-obstructive thrombosis. Clinical information was collected through patient interviews. Non-obstructive thrombosis was defined as a distinct mass (more than 1 mm in width and 2 - 15 mm in length) with abnormal echoes attached to the normally functioning prosthesis and clearly seen throughout the cardiac cycle via two-dimensional, Doppler, and cinefluoroscopy studies. Masses were classified according to their size as small (<5 mm), moderate (5-10 mm), and large (>10 mm). Results- The study recruited 102 consecutive patients (64 female) with a mean age of 51 پ}11.4 years with non-obstructive thrombosis. There were 132 prosthetic valves (PVs), of which 94 were prosthetic mitral valves (PMVs) and 38 were prosthetic aortic valves (PAVs). The mean time between surgery and TEE examination (age of the prosthesis) was 12 پ} 7 years. INR value was less than 1.5 in 50 (49%) cases, between 1.5 – 2.5 in 42 (41.2%) patients, and more than 2.5 in 10 (9.8%). Additionally, 34 (33.3%) patients had recent systemic emboli, 32 (31.9%) had exacerbation of dyspnea, and 14 (13.7%) were asymptomatic. Conclusions- Sub-therapeutic anticoagulation (INR values < 2.5), systemic emboli, and dyspnea are the key factors for the detection of non-obstructive thrombosis. Moreover, TEE is particularly useful when the thrombus is not visualized by TTE (Iranian Heart Journal 2009; 10 (2):20-24).