Monitoring the effect of anticoagulants on left atrial thrombi in patientswith rheumatic heart disease: Assessment with In-111-oxine-labelled platelet heart scintigraphy and transoesophageal echocardiography

In-111-oxine-labelled platelet heart scintigraphy (In-plt) was used to eval uate the activity of left atrial thrombi detected by transoesophageal echoc ardiography (TEE) in 16 cases of rheumatic heart disease. The effect of ant icoagulants on the therapeutic intervention of these patients was evaluated by In-pit and TEE. In-Fit was performed in all patients in serial pre- and post-anticoagulant therapy studies with anterior, 45 degrees left anterior oblique and left lateral views taken daily from the second to sixth day af ter injection of labelled platelets. After discontinuing anticoagulants for at least 1 week, only nine cases of left atrial thrombi were detected amon g the 16 cases by initial Ln-plt. After anticoagulants were again used for at least 3 weeks, all nine positive cases became negative on repeat In-pit. These results suggest that the diagnostic sensitivity of In-pit is lower t han that of TEE. However, In-plt is more suitable and useful for evaluating the activity of left atrial thrombi after antithrombotic agent therapy and for monitoring the effect of anticoagulant therapy on left atrial thrombi in patients with rheumatic heart disease. ((C) 2000 Lippincott Williams & W ilkins).