Introduction: In grading mitral regurgitation (MR) magnetic resonance imaging is the gold standard but 2D echo is mostly used in clinical practice. However, each single echo parameter is prone to confounding influences. With regard to chronic primary and secondary MR the purpose of this study was to compare a new multi-dimensional echo-based grading system with an independent pre-operatively used invasive standard.
Methods: In a retrospective study we analyzed 177 patients with different degrees of MR severity, who were examined both by echocardiography and by cardiac catheterization. For MR grading a combination of four echocardiographic parameters was used: density of the regurgitation velocity profile, peak mitral inflow velocity (Vmax E-wave), radius of the proximal flow convergence zone (PISA), and vena contracta (Vc) width. Invasive grading was based on left ventriculography (Seller's method), V wave hight, and regurgitation fraction. Both methods resulted in an integrative score on an eight point scale (<I-IV in half-steps). Echocardiographic and invasive data were correlated.
Results: There was a reasonable overall correlation of r = 0.72 (p = 0.001) between both grading systems. Echo tended to slightly overestimate MR severity. In patients with secondary MR, agreement was worse (p = 0.01) than in primary MR. The most powerful single echo parameter was Vc r = 0.71 (p = 0.001). Presence or absence of sinus rhythm had no significant influence on echo grading.
Conclusions: The proposed echocardiographic multidimensional MR grading system is feasable and shows good correlation with invasive grading.