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Background and aims: Grading of diastolic function can be useful, but indeterminate classifications are common.

Objectives: We aimed to invasively derive and validate a quantitative echocardiographic estimation of pulmonary artery wedge pressure (PAWP), and to compare its prognostic performance to diastolic dysfunction grading.

Methods: Echocardiographic measures were used to derive an estimated PAWP (ePAWP) using multivariable linear regression in patients undergoing right heart catheterization (RHC). Prognostic associations were analyzed in the National Echocardiography Database of Australia (NEDA).

Results: In patients who had undergone both RHC and echocardiography within two hours (n=90), ePAWP was derived using left atrial volume index, mitral peak early velocity (E), and pulmonary vein systolic velocity (S). In a separate external validation cohort (n=53, simultaneous echocardiography and RHC), ePAWP showed good agreement with invasive PAWP (mean±SD difference 0.5±5.0 mmHg) and good diagnostic accuracy for estimating PAWP>15mmHg (area under the curve [95% confidence interval] 0.94 [0.88-1.00]). Among patients in NEDA (n=38,856, median [interquartile range] follow-up 4.8 [2.3-8.0] years, 2,756 cardiovascular deaths), ePAWP was associated with cardiovascular death even after adjustment for age, sex, and diastolic dysfunction grading (hazard ratio (HR) 1.08 [1.07-1.09] per mmHg) and provided incremental prognostic information to diastolic dysfunction grading (improved C-statistic from 0.65 to 0.68, p<0.001). Increased ePAWP was associated with worse prognosis across all grades of diastolic function (HR normal: 1.07 [1.06-1.09]; indeterminate: 1.08 [1.07-1.09]; abnormal: 1.08 [1.07-1.09], p<0.001 for all).

Conclusions: Echocardiographic ePAWP is an easily acquired continuous variable with good accuracy that associates with prognosis beyond diastolic dysfunction grading.