Echocardiographic atrial and right heart to pulmonary circulation coupling indices identify high-risk in moderate aortic stenosis

Emerging evidence points on an increased mortality risk associated to moderate aortic stenosis (AS), yet this population remains insufficiently characterized. We tested the prognostic value of two echocardiographic coupling indices reflecting right and left-sided cardiac function: the ratio of tricuspid annular plane systolic excursion to pulmonary artery systolic pressure ratio (TAPSE/PASP) and the left atrial volumetric/mechanical coupling index (LACI).

Retrospective, single-center study including 135 patients with moderate AS. TAPSE/PASP was used as a non-invasive surrogate of right ventricular-pulmonary circulation (RV-Pc) coupling, and LACI was defined as ratio of left atrial volume index to mitral a' velocity. The primary endpoint was all-cause mortality. Cox regression and Kaplan-Meier analyses were used to assess the prognostic value of both indices.

During a mean follow-up of 1.61 ± 0.79 years, 33 patients (24%) died. Reduced TAPSE/PASP (< 0.67 mm/mmHg) and elevated LACI (> 5.17) were independently associated with an increased mortality (HR: 3.03 and 3.16, respectively, p < 0.01). These associations remained significant even after adjusting for age. Stratification into three groups - preserved, single, or combined uncoupling -showed progressively lower 1-year survival rates, ranging from 95% to 49% (p < 0.0001). None of the coupling-derived variables was associated with hemodynamic progression or need of aortic valve replacement.

TAPSE/PASP and LACI are independently associated with mortality in patients with moderate AS. These parameters may provide incremental prognostic information in this often-overlooked population. These findings may prompt further studies evaluating the potential role of these parameters in helping to refine prognostic phenotyping.