We retrospectively studied 40 patients who underwent MV repair for atrial functional MR between January 2011 and December 2018 at the Saitama Medical University International Medical Center (mean age, 69 ± 9 years; 68% male (n=27)). All patients had long-standing AF that had persisted for more than 1 year, preserved LV ejection fraction (>40%), and moderate to severe functional MR. Patients with organic valvular heart disease, including rheumatic or degenerative MV disease, a history of coronary artery disease, LV wall motion abnormality, or a history of prior cardiac surgery were excluded from the study because these conditions may confound the results. The patients’ preoperative characteristics are shown in Table 1.
The LA dimension, LV end-diastolic dimension, LV end-systolic dimension, and LV ejection fraction were measured . The MR grade was evaluated using a multiparametric approach, including assessment of the Doppler-derived jet, effective regurgitant orifice area, MR volume and fraction, and pulmonary vein flow velocity pattern [12,13]. The tricuspid regurgitation (TR) grade was also defined using a multiparametric approach [12,13]. Pseudoprolapse of the anterior mitral leaflet (AML) was defined when there was a gap between the AML and the posterior mitral leaflet (PML) due to atriogenic PML tethering [8,10,14,15.]
Through median sternotomy, cardiopulmonary bypass was established using ascending aortic and bicaval cannulation. After sizing the intercommissural distance and AML area, an annuloplasty ring or band [semirigid Future annuloplasty band (n = 1), Medtronic, Minneapolis, MN; Carpentier-Edwards Physio Ring II, Edwards Lifesciences, Irvine, CA (n = 34); Cosgrove annuloplasty band (n = 3), Edwards Lifesciences; or Profile 3D (n = 2), Medtronic] was implanted with interrupted 2-0 Ethibond sutures. In the first half of this study, undersized ring annuloplasty was performed to address annular dilatation and increase the coaptation length. Once we understood the mechanisms of atrial functional MR, we performed true-sized ring annuloplasty to prevent aggravation of PML tethering. In the latter half of the present study, we used only a semi-rigid ring (Carpentier-Edwards Physio Ring II) larger than 28 mm. If AML pseudoprolapse existed, AML neochordoplasty was added. A pair of artificial neochordae with 4-0 or 5-0 polytetrafluoroethylene sutures (Gore-Tex sutures, W.L. Gore & Associates, Newark, DE) was placed at A2 from the anterolateral and posteromedial papillary muscle. Then, the length of the neochordae was adjusted after mitral ring annuloplasty until residual MR was diminished on water saline test. Concomitant tricuspid annuloplasty was performed in patients with severe TR, or mild or moderate TR with a dilated annulus (≥40 mm or >21 mm/m2 by transthoracic echocardiography) . A tricuspid annuloplasty ring [MC3 ring (n = 17), Edwards Lifesciences; Physio Tricuspid annuloplasty ring (n = 10), Edwards Lifesciences; Contour 3D annuloplasty ring (n = 3), Medtronic; or a Tri-Ad Adams tricuspid annuloplasty ring (n = 1), Medtronic] was implanted with interrupted 2-0 Ethibond sutures. The indication of the maze procedure and LA plication was decided at surgeon’s discretion based on the period of atrial fibrillation and the size of LA.
Clinical follow-up examinations were completed for all patients. The mean follow-up period was 42 ± 24 months. Follow-up echocardiography was performed 1 week after surgery and every year after discharge. The mean echocardiographic follow-up period was 26 ± 24 months.
Descriptive statistics were reported as the mean ± standard deviation for continuous variables and as frequencies and percentages for categorical variables unless otherwise noted. A comparison between the groups was performed using Student’s t test or Wilcoxon-Mann-Whitney U-test for continuous variables and the chi-square or Fisher’s exact test for categorical variables. Event-free rates were estimated using Kaplan-Meier analysis. P-values <0.05 were considered to indicate statistical significance. Statistical analyses were performed using JMP software (version 14.1.0; SAS institute, Cary, NC).