Noninvasive estimation of left ventricular filling pressures in patients with heart failure after surgical ventricular restoration and restrictive mitral annuloplasty

Objective

Doppler echocardiography, including tissue Doppler imaging, is widely applied to assess diastolic left ventricular function using early transmitral flow velocity combined with mitral annular velocity as a noninvasive estimate of left ventricular filling pressures. However, the accuracy of early transmitral flow velocity/mitral annular velocity in patients with heart failure, particularly after extensive cardiac surgery, is debated. Global diastolic strain rate during isovolumic relaxation obtained with 2-dimensional speckle-tracking analysis was recently proposed as an alternative approach to estimate left ventricular filling pressures.

Methods

We analyzed diastolic function in patients with heart failure after surgical ventricular restoration and/or restrictive mitral annuloplasty. Echocardiography, including tissue Doppler imaging and speckle-tracking analysis, was performed to determine early transmitral flow velocity/atrial transmitral flow velocity, isovolumetric relaxation time, deceleration time, early transmitral flow velocity/mean mitral annular velocity, strain rate during isovolumic relaxation, and early transmitral flow velocity/strain rate during isovolumic relaxation. These noninvasive indices were correlated with relaxation time constant Tau, peak rate of pressure decline, and left ventricular end-diastolic pressure obtained in the catheterization room using high-fidelity pressure catheters.

Results

Twenty-three patients were analyzed 6 months after restrictive mitral annuloplasty (n = 8), surgical ventricular restoration (n = 4), or a combined procedure (n = 11). The strongest correlation with invasive indices, in particular left ventricular end-diastolic pressure, was found for strain rate during isovolumic relaxation (r = −0.76, P < .001). Early transmitral flow velocity/mean mitral annular velocity did not correlate significantly with any of the invasive indices. Strain rate during isovolumic relaxation (cutoff value < 0.38 s⁻¹) accurately predicted left ventricular end-diastolic pressure of 16 mm Hg or more with 100% sensitivity and 93% specificity.

Conclusions

In a group of patients with heart failure who were investigated 6 months after cardiac surgery, early transmitral flow velocity/mean mitral annular velocity correlated poorly with invasively obtained diastolic indexes. Global strain rate during isovolumic relaxation, however, correlated well with left ventricular end-diastolic pressure and peak rate of pressure decline. Our data suggest that global strain rate during isovolumic relaxation is a promising noninvasive index to assess left ventricular filling pressures in patients with heart failure after extensive cardiac surgery, including restrictive mitral annuloplasty and surgical ventricular restoration.

CTSNet classification: 17, 17.1, 35.4.1, 36.2

Abbreviations and Acronyms: A, atrial transmitral flow velocity, AUC, area under the curve, CABG, coronary artery bypass grafting, dP/dt_MIN, peak rate of pressure decline, DT, deceleration time, E/E′, early transmitral flow velocity/mitral annular velocity, IVRT, isovolumetric relaxation time, LV, left ventricular, LVEDP, left ventricular end-diastolic pressure, RMA, restrictive mitral annuloplasty, SR_IVR, strain rate during isovolumic relaxation, SVR, surgical ventricular restoration