Left Atrial Volume as a Biomarker of Target Organ Damage in Cardio-Nephrology: A Study in a Wide Range of Renal Function

Introduction: Cardio-renal syndrome encompasses a wide variety of pathophysiological processes and sequelae, which includes the effect of renal function impairment on the heart chambers. By now, cardiac chambers` size has been studied by echocardiography, among patients with progressive kidney disease only.

Objectives: We aimed to explore the relations between all heart chambers` volumes and renal function – at all ranges, as assessed by CT pulmonary angiography (CTPA).

Methods: Using a novel technology of automatic four chamber volumetric analysis (4CVA), we analyzed CTPA of 744 consecutive patients without pulmonary embolism (PE), and correlated the chambers` volume indexed to body surface area (BSA), to the estimated glomerular filtration rate (eGFR).

Results: After adjustment for age, inverse linear relation between the LA volume was demonstrated throughout the entire eGFR values, including the normal range of renal function, for all patients (r=-0.425, p<0.001) as well as for each gender separately. Patients with even minimal renal dysfunction (eGFR 60-90 ml/min/1.73m²) had a 10.3% larger left atrial (LA) volume (95% CI 3.1-17.9; p=0.004) compared to patients with an eGFR >90 ml/min/1.73m². The right cardiac chamber volumes had a significant inverse relation to eGFR (for every 10 units increment) as well (-2.3% change 95% CI -3.8 - -0.8, p=0.003; -1.5% change 95% CI -2.6 - -0.4, p=0.007 for the right atrium and right ventricle, respectively).

Conclusions: A simple concomitant volumetric analysis of all four cardiac chambers` volumes of CTPA demonstrated that differences in volumes correlate to renal function even within the spectrum of the normal range. This finding may be the first clue to an evolving cardio-renal syndrome and may serve as a target for early therapeutic interventions.