Three-dimensional left and right atrioventricular coupling indices as prognostic markers in heart failure with reduced ejection fraction

Abstract

Abstract Background While left atrial and left ventricular functional parameters are established prognostic markers in heart failure (HF), recent studies suggest that parameters assessing the atrio-ventricular interaction are better predictors. Left atrioventricular coupling index (LACI) assessed with cardiac magnetic resonance is an emerging outcome predictor in HF patients, however its assessment by three-dimensional (3D) echocardiography hasn't been studied so far. Moreover, the role of the right atrioventricular coupling index (RACI) in HF remains to be established. Purpose We sought to evaluate the LACI, RACI and combined left and right atrioventricular coupling index (CACI) with 3D echocardiography in a cohort of patients with HF and reduced ejection fraction (HFrEF) and to assess their prognostic role. Methods We prospectively enrolled 60 consecutive patients with HFrEF in sinus rhythm, who underwent two dimensional and 3D echocardiographic acquisitions. LACI was calculated as the ratio between 3D left atrial and 3D left ventricular end-diastolic volumes. RACI was calculated as the ratio between 3D right atrial and 3D right ventricular end-diastolic volumes. CACI was defined as the sum between LACI and RACI. Patients were followed for major adverse cardiac events (MACE), defined as a composite endpoint of cardiac death or HF decompensation requiring hospitalization. Results After a mean follow-up of 19±9 months, 33 patients reached the endpoint. Patients with MACE had higher LACI (33.5±21.1% vs. 19.9±12.4%, p=0.003), higher RACI (33.6±23.6% vs. 20.8±13.8%, p=0.01) and higher CACI (67.0±38.0% vs. 40.7±24.4%, p=0.002) – suggestive of atrioventricular decoupling. In ROC analysis, CACI had the best AUC for event prediction (AUC=0.750, p=0.001, cut-off=42.8%, Sen=69.7%, Spe=77.7%), followed by LACI (AUC=0.745, p=0.001, cut-off=20.4%, Sen=72.7%, Spe=70.4%), and then RACI (AUC=0.717, p=0.004, cut-off=18.6%, Sen=75.8%, Spe=70.4%). In unadjusted Cox regression, all three atrioventricular coupling indices were predictors of MACE: HR=3.30 [95% CI, 1.52–7.14], p=0.002 for LACI, HR=4.54 [95% CI, 2.03–10.17], p<0.001 for RACI, HR=3.87 [95% CI, 1.82–8.23], p<0.001 for CACI. A multivariable model was constructed using well-established event predictors in HFrEF: age, global longitudinal strain of the left ventricle, global longitudinal strain of the right ventricular free wall and pulmonary artery systolic pressure. All three atrioventricular coupling indices remained independent predictors of MACE in multivariable regression: HR=3.11 [95% CI, 1.36–7.14], p=0.007 for LACI, HR=4.38 [95% CI, 1.84–10.41], p=0.001 for RACI, HR=3.98 [95% CI, 1.75–9.03], p=0.001 for CACI. Conclusion Greater 3D LACI, RACI and CACI, reflecting atrioventricular uncoupling, are all independent prognostic markers in HFrEF. Funding Acknowledgement Type of funding sources: None.