Indexing of Left Atrial Volume by various body size parameters in the Indian non-obese normal subjects: Is there an incremental value ?

Background

Left atrial (LA) volume indexing for body surface area (BSA) is the common practice. Since LA volume index is of cardiovascular pathophysiologic significance, it is suggested that indexing for other body size parameters be explored to evaluate a more appropriate alternative method. The aims of this study were to find normal and the best cutoff values for LA volume indexed for multiple body size parameters in normal Indian subjects.

Methods

Data from the multicentric prospective INDEA study conducted through 2018 to 2020 was reviewed and subjects without known cardiac disease and completely normal echocardiograms that had the left atrial volume (LAV) measured by biplane Simpson's method were included. LAV was indexed by BSA (ml/m²), by height (LAV/m), by height raised to exponent 1.72 (mL/m ^1.72 and 2.7 (ml/m^2.7), by body weight, by ideal body weight (IBW), by ideal body surface area (IBSA) and by height squared (ml/h²).

Results

A total of 1046 healthy volunteers (382 female, 38%), mean age 38 ± 10.4 years (range 30–48 years) and body mass index 23.6 kg/m² (22–25 kg/m²) were analyzed. Mean and normal values were: LAV/BSA 18.7 + 3.15 ml/m² (range 15–21 ml/m²), LAV/ht 26.0 ± 4.5 ml/m, (range 17–35 ml/m), LAV/ht² 16 ± 2.8 ml/m² (range 10.4–21.6 ml/m²) and LAV/ht^2.7 8.71 ± 2.2 ml/m^2.7 (range 6.98–13.58 ml/m^2.7). Using ROC curve analysis, LAV/h ^1.72 had the highest AUC and the best predictive value to identify LA enlargement but not very different from LAV/BSA. Ideal BSA and ideal body weight as a denominator did not provide any incremental value.

Conclusion

Normal values for LAV indexed for height, weight, body surface area by three different methods of height as an allometric parameter are described in normal Indian individuals. We reinforce that LA volume indexation for BSA is an acceptable and robust method in non-obese Indian subjects. Indexing for height ^1.72 is probably slightly superior method to evaluate LAV.