Prognostic importance of left atrial size measured by non-contrast cardiac computed tomography - A DANCAVAS study

BACKGROUND

Enlargement of left atrium (LA) is a valuable marker of cardiovascular events, and LA size is readily available while performing non-contrast cardiac computed tomography (NCCT) for preventive purposes. We aimed to evaluate the predictive value of a single LA area from NCCT in a population-based cohort.

METHOD

Mainly men aged 60-75 years from DANCAVAS were included. Traditional risk factors were recorded, and an NCCT scan performed at baseline. Coronary artery calcifications (CAC) score and the largest LA area were measured. LA was indexed to body surface area and categorised into four groups. Data on incident atrial fibrillation (AF), thromboembolic events, heart failure (HF) and death were obtained from Danish national registries.

RESULTS

In total, 14,557 individuals were eligible, excluding those without LA measurement (N = 232) and with heart valve replacement (N = 197). Known AF or HF were respectively excluded from follow-up. Median follow-up time was 2.1 to 3.4 years. In total, 304 developed AF, 149 had thromboembolism, 129 developed HF and 482 died. In adjusted analysis, LA enlargement was associated with AF (HR (95% CI): large 1.99 (1.46-2.71) and very large LA 3.77 (2.31-6.14)) and HF (large 2.40 (1.50-3.85) and very large LA 6.54 (4.07-10.51)). A very large LA significantly increased mortality (HR: 2.01 (1.44-2.82)), and was associated with a two-fold increased risk of thromboembolism; however, not significantly in adjusted analysis (p = 0.09).

CONCLUSION

We demonstrated that determination of LA area from NCCT was an important predictor of AF, HF and death. This knowledge could inform current risk assessment beyond CAC score.

Left ventricular area on non-contrast cardiac computed tomography as a predictor of incident heart failure - The Multi-Ethnic Study of Atherosclerosis

BACKGROUND

The use of non-contrast cardiac computed tomography measurements to predict heart failure (HF) has not been studied. In the present study we evaluated the prognostic value of left ventricular area adjusted for the body surface area (LVA-BSA) measured by non-contrast cardiac CT to predict incident HF and cardiovascular disease (CVD) events.

METHODS

We studied left ventricular dimensions and calculated LVA-BSA in 6781 participants of the MESA study (mean age: was 62 ± 10 years, 53% females; 62% non-white) free from prior HF who underwent non-contrast cardiac CT to evaluate the coronary artery calcium score (CAC) at baseline and were followed up for a median of 10.2 years.

RESULTS

During follow up, 237 (3.5%) incident HF and 475 (7.0%) CVD events occurred. After adjustment for clinical variables and CAC, LVA-BSA was significantly associated with incident HF (hazard ratio [HR]: 1.10 per 100 mm²/m², p < 0.001) and CVD events (HR: 1.07 per 100 mm²/m², p < 0.001). The area under the ROC curve for the prediction of incident HF improved from 0.787 on a model including only risk factors to 0.798 when CAC was added (p = 0.02), and to 0.816 with the additional inclusion of LVA-BSA (p = 0.007). Similar improvements for the prediction of CVD events were noted.

CONCLUSION

In an ethnically diverse population of asymptomatic individuals free from baseline CVD or HF, the left ventricular area measured by non-contrast cardiac CT is a strong predictor of incident HF events beyond traditional risk factors and CAC score.