Effects of Mitral Valve Prolapse on Quantification of Mitral Regurgitation and Ejection Fraction Using Cardiac MRI.

ABSTRACT

Purpose: To determine the impact of prolapsed volume on regurgitant volume (RegV), regurgitant fraction (RF), and left ventricular ejection fraction (LVEF) in patients with mitral valve prolapse (MVP) using cardiac MRI. Materials and Methods: Patients with MVP and mitral regurgitation who underwent cardiac MRI from 2005 to 2020 were identified retrospectively from the electronic record. RegV is the difference between left ventricular stroke volume (LVSV) and aortic flow. Left ventricular end-systolic volume (LVESV) and LVSV were obtained from volumetric cine images, with prolapsed volume inclusion (LVESVp, LVSVp) and exclusion (LVESVa, LVSVa) providing two estimates of RegV (RegVp, RegVa), RF (RFp, RFa), and LVEF (LVEFa, LVEFp). Interobserver agreement for LVESVp was assessed using intraclass correlation coefficient (ICC). RegV was also calculated independently using measurements from mitral inflow and aortic net flow phase-contrast imaging as the reference standard (RegVg). Results: The study included 19 patients (mean age, 28 years ± 16 [SD]; 10 male patients). Interobserver agreement for LVESVp was high (ICC, 0.98; 95% CI 0.96, 0.99). Prolapsed volume inclusion resulted in higher LVESV (LVESVp 95.4 mL ± 34.7 vs LVESVa 82.4 mL ± 33.8; P < .001), lower LVSV (LVSVp 100.5 mL ± 33.8 vs LVSVa 113.5 mL ± 35.9; P < .001), and lower LVEF (LVEFp 51.7% ± 5.7 vs LVEFa 58.6% ± 6.3; P < .001). RegV was larger in magnitude when prolapsed volume was excluded (RegVa 39.4 mL ± 21.0 vs RegVg 25.8 mL ± 22.8; P = .02), with no evidence of a difference when including prolapsed volume (RegVp 26.4 mL ± 16.4 vs RegVg 25.8 mL ± 22.8; P > .99). Conclusion: Measurements that included prolapsed volume most closely reflected mitral regurgitation severity, but inclusion of this volume resulted in a lower LVEF.Keywords Cardiac, MRI© RSNA, 2023See also commentary by Lee and Markl in this issue.