ABSTRACT
Transthoracic echocardiography (TTE) is the most commonly used imaging modality to diagnose left ventricular thrombus (LVT), however, cardiac magnetic resonance (CMR) remains the gold standard investigation. A comparison of the diagnostic performance between two modalities is needed to inform guidelines on a diagnostic approach towards LVT. We performed a systematic review and meta-analysis to investigate the diagnostic performance of three methods of TTE (non-contrast, contrast, and apical wall motion scoring) for the detection of LVT compared to CMR as a reference test. Studies comprising 2113 patients investigated for LVT using both TTE and CMR were included in the meta-analysis. For non-contrast TTE, pooled sensitivity and specificity were 47% [95% confidence interval (CI): 32-62%], and 98% (95% CI: 96-99%), respectively. In contrast, TTE pooled sensitivity and specificity values were 58% (95% CI: 46-69%), and 98% (95% CI: 96-99%), respectively. Apical wall motion scoring on non-contrast TTE yielded a sensitivity of 100% [95% CI: 93-100%] and a specificity of 54% (95% CI: 42-65%). The area under the curve (AUC) values from our summary receiver operating characteristic curve (SROC) for non-contrast and contrast TTE were 0.87 and 0.86 respectively, with apical wall motion studies having the highest AUC of 0.93. Despite high specificity, routine contrast and non-contrast TTE are likely to miss a significant number of LVT, making it a suboptimal screening tool. The addition of apical wall motion scoring provides a promising method to reliably identify patients requiring further investigations for LVT, whilst excluding others from unnecessary testing.
The formation of left ventricular thrombus (LVT), a blood clot in the left pumping chamber of the heart, can lead to serious complications such as a stroke. Whilst cardiac magnetic resonance (CMR) is the best imaging tool to detect these clots, the most used tool is a transthoracic echocardiogram (TTE), which visualizes the heart by placing an ultrasound on the chest. This is due to the affordability and widespread availability of TTE. Thus, it is important to know how TTE compares to CMR when it comes to detecting LVT. This study pools the results of previous research to compare the diagnostic performance of three different methods of TTE compared to CMR for detecting LVT. Non-contrast TTE.Contrast TTE: The addition of an enhancing dye is thought to improve imaging.Apical wall motion scoring: Evaluating the movement of the heart's walls using TTE. Our results show that current methods of TTE may miss half of the patients with LVT and that the use of contrast did not provide significant improvement. Interestingly, the use of apical wall motion scoring was able to accurately detect all the patients with LVT. This shows promise as a future tool to reliably exclude patients from unnecessary testing, whilst identifying those who need further investigations.
