Diastolic pressure-volume quotient (DPVQ) as a novel echocardiographic index for estimation of LV stiffness in HFpEF

BACKGROUND: End-diastolic pressure-volume relationship and LV stiffness, key parameter for diagnosing diastolic dysfunction within Heart failure with preserved ejection fraction (HFpEF) patients, can be directly obtained only by invasive pressure-volume (PV) measurements. Therefore, we aimed to establish diastolic pressure-volume quotient (DPVQ), as a new non-invasive parameter for estimation of LV stiffness in HFpEF obtained by 3D echocardiography (3DE) and tissue Doppler imaging. METHODS: Twenty-three HFpEF patients with suspected diastolic dysfunction, scheduled for invasive pressure-volume loop analyses obtained by conductance catheterization were included. PV loop measurements were compared with simultaneous 3DE full-volume recordings of the LV and tissue Doppler measurements for LV diastolic function. LV filling index E/E’ was used for estimation of diastolic pressure. Single-beat method was performed to calculate LV stiffness constant (beta SB). RESULTS: Fourteen of twenty-three patients showed increased and 9/23 revealed normal LV stiffness beta. End-diastolic, end-systolic and stroke volume obtained by 3DE correlated with those from PV loop analysis (r = 0.63, r = 0.57 and r = 0.71, respectively). Estimated diastolic pressure and DPVQ correlated with invasive measurements (r = 0.81 and r = 0.91, both p < 0.001). Accordingly, calculated stiffness constant beta SB revealed a significant correlation with invasive determined stiffness coefficient beta (r = 0.73, p < 0.001). DPVQ and beta SB correlated with NT-proBNP plasma level (r = 0.67 and r = 0.58, both, p < 0.001). CONCLUSION: 3D echocardiography allows accurate non-invasive measurements of diastolic pressure-volume quotient which correlates with invasive determined LV stiffness in HFpEF