We aimed to evaluate a combination diagnostic method of single-phased, single-contrast injection cardiac computed tomography angiography CTA combined with age-adjusted D-dimer assay for diagnosis of left atrial/left atrial appendage (LA/LAA) thrombus in comparison to transesophageal echocardiography (TEE) in patients with atrial fibrillation. The addition of D-dimer to the CTA is to increase specificity, since CTA is part of the combined method.

Between October 2016 and December 2017, 113consective patients with non-valvular or valvular AF (male: 72.6%; mean age: 57.9 ± 11.5 y) underwent diagnostic work-up, included TEE, single-phased, single contrast injection cardiac CTA, and age-adjusted D-dimer assay, for the evaluation of LA/LAA thrombus formation.

Cardiac CTA identified 32 patients with filling defects in LA or LAA. Of these patients, 17 had an elevated D-dimer value according to age-adjusted cut-off. TEE detected definitive thrombus formation in 15 patients. Using TEE as the reference standard, the combination diagnostic method had a sensitivity of 100.0%, specificity of 97.9%, positive predictive value (PPV) of 88.2, and negative predictive value of 100.0%. Further, compared to cardiac CTA alone, the combination diagnostic method had significantly better specificity (82.7% vs. 97.9%, respectively; p < 0.01) and PPV (46.9% vs. 88.2%, respectively; p < 0.01).

The combination diagnostic method comprising single-phase, single-contrast injection cardiac CTA and age-adjusted D-dimer assay had good diagnostic efficacy for the detection of LA/LAA thrombus in patients with AF. The combination diagnostic method had significantly better specificity and PPV than cardiac CTA alone.

The presented diagnostic approach could potentially facilitate rapid diagnosis or exclusion of left atrial thrombus under emergency situation or when TEE is un-available, with good diagnostic efficacy and no TEE related risks.