Evaluation of Hemodynamics After Mitral Valve Repair for Degenerative Mitral Disease using Stress Echocardiography

Objective: The purposes of this study are to evaluate the hemodynamics of patients with mitral valve repair (MVR) using annuloplasty devices for degenerative MR during exercise, and to evaluate the relationships between these parameters and indexed ring orifice area (iROA). Methods: Sixty-one patients (mean age, 58 years, M/F=43/18) who underwent MVR for degenerative MR had been studied by exercise stress echocardiography (ESE). The workload during ESE was increased at a rate of 25 Watts. Patients were divided into two groups according to their iROA (geometric annuloplasty ring orifice area/BSA) (Group S: iROA< 300mm2, n=29, Group L: iROA ≥ 300mm2, n=32). Changes of cardiac index (CI), stroke volume index (SVI), heart rate (HR), and mean pressure gradient across the mitral valve (mPG) were measured at each workload, and differences of these parameters between two groups were evaluated. Results: There was no intergroup difference in mean age, sex, BSA, LVEF, and annuloplasty devices. In both groups, CI increased proportionally to workload, and there was no significant difference in CI at each workload between groups (Fig. A). HR and mPG increased significantly in response to exercise in both groups, however, HR at each workload and mPG at rest and each workload were significantly higher in Group S (Fig. B, C). Though the absolute SVI value of the two groups at each workload did not show statistical difference (Fig. D), increment of SVI (δSVI) from minimum (at rest) to maximum value was significantly larger in Group L (δSVI in Group L: 9.8 ml/m2 vs. Group S: 6.2 ml/m2, p=0.007). Conclusions: CI during exercise was preserved both in patients with smaller and larger iROA. However, CI increase was adjusted by higher HR at the cost of higher mPG in smaller iROA patients, whereas CI increase in larger iROA patients tended to depend on SVI increase along with lower mPG. KEYWORD: e-PD-03 H. YAKU declares a conflict of interest: Medtronic consultant.