Clinical Significance and Prognostic Value of Novel Echocardiographic Index for the Severity of Mitral Regurgitation

Abstract

Background: Recently, the left ventricular early inflow-outflow index (LVEIO), calculated by dividing mitral E-wave velocity by the left ventricular outflow velocity time integral, has been proposed as a simple method for evaluating mitral regurgitation (MR). This study determined the optimal LVEIO threshold to assess severe MR with different etiologies and assessed its prognostic value. Methods and Results: The records of 18,692 consecutive patients who underwent echocardiography were reviewed. MR was classified into 4 groups: Grade 0/1, no, trivial, or mild MR; Grade 2, moderate MR; Grade 3, moderate to severe MR; and Grade 4, severe MR. The mean (±SD) LVEIO of Grades 0/1, 2, 3, and 4 was 3.6±1.4, 6.0±2.5, 7.4±3.1, and 9.5±2.8, respectively. An optimal LVEIO threshold of 5.4 was determined to distinguish moderate to severe or severe MR from non-severe MR (sensitivity 84%, specificity 91%). Kaplan-Meier survival analysis revealed high mortality in the group with LVEIO ≥5.4 (P=0.009, hazard ratio 1.833). This was found only in primary MR when separate analyses were performed according to etiology. Multivariate analysis revealed that LVEIO was an independent predictor for all-cause death only in primary MR. Conclusions: Using appropriate thresholds, LVEIO is a simple and useful method to diagnose severe MR regardless of etiology. LVEIO can also be useful for predicting prognosis in primary MR.

The RVEIO and RV function: More, please

“…The concept of RVEIO came from the recently‐derived left ventricular early inflow‐outflow (LVEIO) index, described in 2015 as a simplified construct relating to regurgitant fraction in severe mitral regurgitation (MR) 5–7 . Conventionally, mitral regurgitant volume can be calculated as the difference between the total inflow volume crossing the mitral valve in diastole from the smaller outflow volume that exits the LVOT in systole.…”

“…In n = 6264 echocardiograms, LVEIO rose with increasing regurgitant fraction, and when LVEIO ≥8, there was a likelihood ratio of 26.5 for severe MR. 5 In a study of n = 18 692 echo studies, an LVEIO ≥5.4 had an 85% sensitivity and 90% specificity in detecting severe MR and was related to patient mortality. 7 Since the E wave rises with left atrial pressures, it can be particularly difficult to disentangle the causes of the higher E wave velocity in patients with both CHF and functional MR, as evidenced by a significant fall in AUC of 0.92 to 0.80 when LVEIO was used in those patients with EF < 50%. 5 Further complicating the outcome analyses, left atrial compliance likely plays a role in accommodating some of the regurgitant volume and pressure, thereby lessening the degree and impact of resultant pulmonary edema.…”

“…The concept of RVEIO came from the recently-derived left ventricular early inflow-outflow (LVEIO) index, described in 2015 as a simplified construct relating to regurgitant fraction in severe mitral regurgitation (MR). [5][6][7] Conventionally, mitral regurgitant volume can be calculated as the difference between the total inflow volume crossing the mitral valve in diastole from the smaller outflow volume that exits the LVOT in systole. In the LVEIO numerator, the peak velocity of the inflow wave, E ("early" diastolic), is a surrogate for total inflow and reflects the sum of the pulmonary venous flow and the prior beat's regurgitant volume that initially crosses the mitral orifice and relates to the severity of MR.…”