Higher Mortality in Case of Small Left Atrium on Nongated Computed Tomography Pulmonary Angiography Is Associated with the Presence of Malignancy

Purpose: The purpose of this study was to evaluate the association between small left atria (LA) according to computed tomography pulmonary angiography (CTPA) and mortality among individuals without pulmonary embolism, and to examine which volumes begin to portend adverse outcomes. Materials and Methods: Left atrial volume indices (LAVIs) of 752 consecutive patients who underwent CTPA, in which pulmonary embolism were ruled out, were measured retrospectively using an automatic 4-chamber volumetric analysis software. Groups of 5 percentiles within the lower quartile were investigated, and the interquartile range (25th to 75th percentiles) was regarded as the control group. Results: Patients within the lower 25th LAVI percentiles (<33 mL/m²; n=188) were younger and had less cardiovascular morbidities, while malignancies were less common in the control group (LAVI: 33 to 54 mL/m²; n=376). Percentiles 5th to 25th did not demonstrate an independent association with mortality. After adjustment for baseline characteristics, the risk for 30-day and 1-year mortality was 5.6 (95% confidence interval: 2.1-14.8, P=0.001) and 6.1 (95% confidence interval: 2.4-15.1, P<0.001) times higher, respectively, among the lowest five LAVI percentiles (<24 mL/m²) compared with the control group. Among patients with small LA who died within 1 year, 83% had a diagnosis of malignancy. Albeit, only a minority (3%) of patients with malignancies had small LA. Conclusions: Individuals undergoing CTPA whose LAVI is within the lowest five percentiles have a markedly increased risk for short-term and long-term mortality. The risk can probably be attributed to an underlying malignancy. The feasibility of 4-chamber volumetric analysis while avoiding a time-consuming process due to the automatic properties enables the introduction of this feature to clinical practice.