Purpose: The differential diagnosis and prognostic implications of small left atria has not been explored extensively. We aim to evaluate the association between very small left atria (VSLA) on non-gated CT pulmonary angiography (CTPA) and mortality in patients without pulmonary embolism (PE).
Methods: Patients investigated for dyspnea who underwent non-gated CTPA between 2011-2015 in order to rule out PE, and had an echocardiogram within 24 hours of the CTPA, were retrospectively identified. The left atrial volume (LAV) of non-gated CTPA was calculated using automatic 4 chamber volumetric analysis (4 CVA) software. The association between the lowest 5th percentile of LAV, indexed to body surface area (BSA), and mortality was investigated after adjustment for age, gender, background diseases and laboratory values.
Results: The study cohort included 241 patients with a median age of 72 (IQR 54-81). The median LAV/BSA was 43.6mL/m2 (IQR 33.3-57.2). Patients in the lowest 5th percentile of LAV/BSAhad avolume/BSA of <24mL/m2 (n=11), and were regarded as the VSLA group. Demographics and background diseases did not differ between the study groups. Median follow-up was 22.7 months (IQR 0.03-54.3). VSLA was an independent predictor of mortality (HRadj=3.6, 95% CI 1.46-8.87; p=0.005), along with malignancy (HRadj=2.28, 95% CI 1.32-3.93; p=0.003) and lower hemoglobin concentrations (HRadj=0.86, 95% CI 0.76-0.99; p=0.032).
Conclusions: Our findings suggest that very small left atria on non-gated CTPA may serve as a marker for mortality. The use of CTPA volumetric analysis can help risk stratification in patients with dyspnea and no PE.
