Background: Noninvasive echocardiographic differentiation between old and fresh left ventricular thrombi after myocardial infarction would be of clinical importance to estimate the risk for embolization and the necessity of anticoagulation.
Methods and results: Fifty-two patients, aged 41 to 87 years, with a thrombus after myocardial infarction were included in this 2-part study: In substudy-I, 20 patients, 10 each with a definite diagnosis of fresh or old thrombus, were included. In the subsequent prospective substudy-II, 32 consecutive patients with an incident thrombus after myocardial infarction but unknown thrombus age were started on phenprocoumon and followed for 6 months. Data on medical history, standard echocardiography, strain-rate (SR) imaging and magnetic resonance tomography were analyzed. In substudy-I, analysis of thrombus deformation revealed the most rapid change in SR during the isovolumetric relaxation period when cavity pressure decreases rapidly. Fresh (range: 5-27 days) and old thrombi (4-26 months) could be discriminated without overlap by peak SR during the isovolumetric relaxation period, using a cutoff value of 1 s(-1). Applying this threshold value in substudy-II, 17 thrombi were echocardiographically classified as fresh (=SR ≥1 s(-1)) and 15 as old. After 6 months in the fresh thrombus group, 16 of 17 thrombi had disappeared (94%), and in 1 patient the thrombus size was diminished by >50% (now presenting an old thrombus SR pattern). In contrast, 14 of the 15 old thrombi remained unchanged in size and deformation (1 thrombus disappeared).
Conclusions: Fresh and old intracavitary thrombi can be reliably differentiated by deformation imaging. In fresh thrombi, anticoagulation with phenprocoumon results in thrombus resolution in most patients.