Author + information
- Tomasz Barona,b,
- Lovisa Holm Orndahla,b,
- Tanja Keroa,b,
- Jens Sorensena,b,
- Tomas Bjernera,b,
- Eva-Maria Hedina,b,
- Elisabeth Stahlea,b and
- Frank Flachskampfa,b
Background: Assessment of asymptomatic patients with severe mitral regurgitation (MR) and preserved left ventricular (LV) ejection fraction (EF) is difficult. We aimed to compare the volumetric measurements by transthoracic echocardiography (echo) and cardiac magnetic resonance imaging (MRI) with independent validation of forward stroke volume by dynamic positron emission tomography (PET) in such patients.
Methods: 18 asymptomatic patients with severe MR underwent a dynamic (11)C-acetate PET scan directly followed by cardiac MRI and echo. LV end-diastolic volume (EDV), end-systolic volume (ESV) and total stroke volume (SV), as well as EF and mitral regurgitant volume (RVol) were measured by echo and MRI. Mitral RVol was calculated on echo by proximal convergence or “PISA” method and on MRI by subtracting forward SV from total LV SV. Forward SV was also obtained independently by PET using indicator dilution theory.
Results: LV volumes measured by MRI were significantly higher than by echo (EDV 250.7±51.0 vs. 157.1±34.9 ml, ESV 89.3±26.9 vs. 48.6±12.6 ml, total SV 161.4±31.2 vs. 108.5±25.3 ml; p<0.001 for all comparisons), but showed a good or modest correlation (r=0.74, p=0.002 for EDV, r=0.72, p=0.003 for ESV and r=0.58, p=0.023 for SV). Contrary, the mitral Rvol was significantly lower by MRI as compared to echo (71.8±35.0 vs. 113.9±77.1 ml), since the use of the PISA method by echo led to very large effective regurgitant areas (0.72±0.50 cm2), leading to unrealistic estimation of mitral RVol, in spite of modest correlation with MRI (r=0.60, p=0.015). Forward stroke volumes by cardiac MRI and PET correlated strongly (r=0.84, p<0.001).
Conclusions: As compared to MRI, echo heavily underestimates LV volumes, but overestimates regurgitant volumes calculated by the proximal convergence method in patients with severe degenerative mitral regurgitation and preserved LV systolic function. Forward stroke volume by MRI used for indirect quantification of severity of mitral regurgitation showed good agreement with PET suggesting advantage of volumetric calculation of regurgitant volume by MRI, while the usefulness of PISA method in this selected group of patients might be limited.
Poster Hall, Hall C
Friday, March 17, 2017, 3:45 p.m.-4:30 p.m.
Session Title: Valvular Heart Disease: Mitral Valve Disease
Abstract Category: 36. Valvular Heart Disease: Clinical
Presentation Number: 1145-031
- 2017 American College of Cardiology Foundation