Correcting left ventricular stroke volume for the prolapsed volume in patients with bileaflet mitral valve prolapse significantly reduced the calculated regurgitant volume and reclassified MR severity to a milder grade in 66% of patients.
Observational (n=35)
No
Does correcting left ventricular stroke volume for prolapse volume improve the accuracy of mitral regurgitation quantification by CMR in patients with mitral valve prolapse?
In patients with prominent mitral valve prolapse, correcting left ventricular stroke volume for prolapse volume during CMR prevents systematic overestimation of mitral regurgitation severity.
Absolute Event Rate: 14.1% vs 30.7%
p-value: p=<0.0001
Background To quantify mitral regurgitation (MR) with CMR , the regurgitant volume can be calculated as the difference between the left ventricular (LV) stroke volume (SV) measured with the Simpson's method and the reference SV, i.e. the right ventricular SV (RVSV) in patients without tricuspid regurgitation . However, for patients with prominent mitral valve prolapse (MVP), the Simpson's method may underestimate the LV end-systolic volume (LVESV) as it only considers the volume located between the apex and the mitral annulus , and neglects the ventricular volume that is displaced into the left atrium but contained within the prolapsed mitral leaflets at end systole. This may lead to an underestimation of LVESV, and resulting an over-estimation of LVSV, and an over-estimation of mitral regurgitation . The aim of the present study was to assess the impact of prominent MVP on MR quantification by CMR. Methods In patients with MVP (and no more than trace tricuspid regurgitation) MR was quantified by calculating the regurgitant volume as the difference between LVSV and RVSV. LVSV uncorr was calculated conventionally as LV end-diastolic (LVEDV) minus LVESV. A corrected LVESV corr was calculated as the LVESV plus the prolapsed volume, i.e. the volume between the mitral annulus and the prolapsing mitral leaflets. The 2 methods were compared with respect to the MR grading. MR grades were defined as absent or trace, mild (5–29% regurgitant fraction (RF)), moderate (30–49% RF), or severe (≥50% RF). Results In 35 patients (44.0 ± 23.0y, 14 males, 20 patients with MR) the prolapsed volume was 16.5 ± 8.7 ml. The 2 methods were concordant in only 12 (34%) patients, as the uncorrected method indicated a 1-grade higher MR severity in 23 (66%) patients. For the uncorrected/corrected method, the distribution of the MR grades as absent-trace (0 vs 11, respectively), mild (20 vs 18, respectively), moderate (11 vs 5, respectively), and severe (4 vs 1, respectively) was significantly different ( p < 0.001). In the subgroup without MR, LVSV corr was not significantly different from RVSV (difference: 2.5 ± 4.7 ml, p = 0.11 vs 0) while a systematic overestimation was observed with LVSV uncorr (difference: 16.9 ± 9.1 ml, p = 0.0007 vs 0). Also, RVSV was highly correlated with aortic forward flow ( n = 24, R 2 = 0.97, p < 0.001). Conclusion For patients with severe bileaflet prolapse, the correction of the LVSV for the prolapse volume is suggested as it modified the assessment of MR severity by one grade in a large portion of patients.
Vincenti et al. (2016) conducted an observational in Bileaflet mitral valve prolapse (n=35). Prolapse-corrected left ventricular stroke volume method vs. Uncorrected Simpson's method was evaluated on Regurgitant volume (ml) (p=<0.0001). Correcting left ventricular stroke volume for the prolapsed volume in patients with bileaflet mitral valve prolapse significantly reduced the calculated regurgitant volume and reclassified MR severity to a milder grade in 66% of patients.