Abstract 13052: Sub-Optimal Detection of Left Ventricular Thrombi with 2D Transthoracic Echocardiography Compared to Cardiac Magnetic Resonance Despite the Use of Contrast Echocardiography

Abstract

Background: Two Dimensional transthoracic echocardiography (TTE) is routinely utilized for the assessment of Left Ventricular (LV) thrombus. Recent studies have demonstrated a more accurate detection of LV thrombus by contrast enhanced cardiac magnetic resonance (CE-CMR). Whether the use of contrast echocardiography (CEcho) improves the detection of LV thrombus by TTE to a degree similar to CMR is still unclear.

Aim: To compare TTE (without and with CEcho) to CE-CMR in the assessment of LV thrombus.

Methods: Patients were identified from both TTE and CE-CMR databases from 2008 to 2011 who had both studies performed for clinical indications such as stroke or suspected cardio-embolic source, myocardial infarction, heart failure or cardiomyopathy. The patients who underwent both TTE and CE-CMR studies within 7 days of each other and without an interim anticoagulation or interventions were included.

Results: A total of 481 patients were identified. There were 49 patients with thrombus by CE-CMR; mean time between the 2 studies was 2.6±2.0 days. Non -contrast TTE identified 9 definite thrombi (18%) and another 9 (18%) as suspicious for thrombi (total 36%). The addition of contrast echo (n=34) improved the definite detection of thrombi to only 42%. Specificity for thrombi with non-contrast TTE was 98% and was 93% with CEcho. The detection rate of TTE for small (< 5 mm) thrombi was lower than for medium or large thrombi (≥ 5 mm): 3/9 (33%) vs. 18/40 (45%) respectively. The rate of detection of TTE for layered thrombi was lower than by CE-CMR (4.7% vs. 26.5%, p<0.001). Review of the missed cases, despite knowledge of thrombus, revealed findings of a wall motion abnormality and a non specific area of increased echogenicity with echocardiography.

Conclusion: TTE significantly underestimates the presence of LV thrombus compared to CE-CMR. While the addition of contrast echo improves the detection and interpretive confidence of TTE, identification of thrombus is still suboptimal. The missed thrombi are usually small, layered and incorporated into the wall of the LV. Whether 3D echocardiography with contrast further improves the detection of thrombi remains to be determined.