Dynamics of mitral regurgitant flow and orifice area. Physiologic application of the proximal flow convergence method: clinical data and experimental testing.

Abstract

The proximal flow convergence method demonstrates that regurgitant flow and orifice area vary throughout systole in distinct patterns characteristic of the underlying mechanism of mitral incompetence. Therefore, in addition to the potential of the method as a tool to quantify mitral regurgitation, it allows analysis of the pathophysiology of regurgitation in the individual patient, which may be helpful in clinical decision making. Calculating mitral regurgitant flow rate and volume from the time-varying proximal flow field (ie, without assuming a constant orifice area that would produce overestimation in individual patients) provides excellent agreement with independent te

Mitral Valve Prolapse With Mid-Late Systolic Mitral Regurgitation

“…In patients with MVP, the dynamic nature of MR during the cardiac cycle is well documented, 17,18 but little attention has been directed toward MVP with mid-late systolic MR. 19 Previous outcome studies of organic MR either included exclusively holosystolic MR 12 or did not address the specific outcome of mid-late systolic MR. 10,11,14,28 -30 We report herein the first sizable series of patients with mid-late systolic MR due to MVP with prospective, quantitative assessment and analysis of long-term outcome. Our study shows that purely mid-late systolic MR due to MVP can be particularly misleading.…”

“…32 Doppler echocardiography subsequently demonstrated the dynamic MR of MVP, 17,18 with MVP progression throughout systole even in patients with holosystolic MR. Pathophysiologically, as systole progresses, LV volume decreases, causing increasing mitral billowing, 33 which, compounded by the dysfunctional enlarging mitral annulus, 34 leads to wider ERO, so that most of the regurgitant volume penetrates the LA in mid-late systole. 17,18 With dynamic ERO measured by the instantaneous flow convergence method, concerns in regard to accuracy were raised, but ERO measured at peak MR velocity closely reflects average holosystolic ERO 18 and determines outcome. 12 Mid-late systolic MR has not been well studied, and the observation that it may have serious clinical consequences 19 raised the issue that marked late-systolic MR predominance 17,18 makes the differentiation of MR presence in early systole an academic consideration of little clinical significance.…”

“…MR associated with MVP is dynamic 17,18 predominantly or purely in the later phase of systole (mid-late systolic MR). Patients with MR that is not holosystolic were not represented in outcome studies, 12 and it is not possible to determine whether such patients incur the same consequences (ventricular, atrial, hemodynamic, outcome) as their counterparts with holosystolic MR and whether the measured ERO carries similar implications in mid-late systolic MR and holosystolic MR. From the theoretical physiological point of view, there is relative equipoise in that regard.…”

Chordal Cutting

“…Mitral geometry was analyzed at midsystole (time of closest leafletannulus approach). 6,24 The 3D leaflet surface area separating the atrial and ventricular cavities (that is, not including any surfaces where the leaflets coapt) was reconstructed from intersecting leaflet traces using a validated surfacing algorithm. 21 This calculation provided the minimum surface area needed to occlude the orifice as dictated by the shape of the mitral leaflets; this was defined as the leaflet covering area (Figure 3).…”

Paradoxic Decrease in Ischemic Mitral Regurgitation With Papillary Muscle Dysfunction

“…Mitral geometry was analyzed at mid-systole (time of closest leafletannulus approach). 6,24 The PMs were traced, and their most basal and anterior tips were identified from several adjacent images.…”