Calculation of Regurgitant Volume Using Echocardiographic Volumetric Method for Accurate Diagnosis of Severe Mitral Regurgitation.

Abstract

Objectives: To evaluate the accuracy of regurgitant volume calculated by volumetric transthoracic echocardiography (RegVol__TTE) for diagnosing severe primary mitral regurgitation (MR).

Background: Recent studies have shown suboptimal results of the proximal isovelocity surface area (PISA) method and the American Society of Echocardiography (ASE) algorithm for diagnosing severe primary MR.

Methods: A total of 74 patients with primary MR due to prolapse or flail leaflet were prospectively recruited for both TTE and cardiac magnetic resonance imaging (CMR). RegVol was calculated using PISA (RegVol__PISA) or the volumetric method (left ventricular total stroke volume-systolic forward outflow volume; RegVol__TTE). According to the ASE algorithm, patients with four or more parameters were diagnosed with severe MR. RegVol__CMR of ≥60 mL was used as the gold standard for diagnosing severe MR.

Results: All subjects had at least moderate to severe MR based on ASE guidelines. CMR confirmed that 30 patients (41%) had severe MR. The concordance correlation coefficient between RegVol__TTE and RegVol__CMR (0.809; 95% confidence interval [CI], 0.715-0.893) was higher than that between RegVol__PISA and RegVol__CMR (0.468; 95% CI, 0.323-0.576). The overall accuracy of RegVol__TTE for the diagnosis of severe MR was 90.5% (95% CI, 81.5-96.1), which was significantly higher than that of RegVol__PISA (64.9%; 95% CI, 52.9-75.6; p<0.001) and the ASE algorithm (77.0%; 95% CI, 65.8-86.0; p=0.004). The area under the curve of RegVol__TTE (0.95; 95% CI, 0.90-1.00) was significantly larger than that of RegVol__PISA (0.88; 95% CI, 0.80-0.96; p=0.028).

Conclusions: RegVol__TTE showed better diagnostic performance than the PISA method and the ASE algorithm in diagnosing severe MR. Further investigations are necessary to evaluate the clinical usefulness of routine utilization of RegVol__TTE.