Gen Thorac Cardiovasc Surg DOI 10.1007/s11748-013-0341-2
ORIGINAL ARTICLE
Post-repair coaptation length and durability of mitral valve repair for posterior mitral valve prolapse Tomoya Uchimuro • Minoru Tabata • Kiyomi Saito • Kentaro Shibayama • Hiroyuki Watanabe • Toshihiro Fukui • Tomoki Shimokawa • Hitoshi Kasegawa • Shuichiro Takanashi
Received: 18 January 2013 / Accepted: 29 October 2013 Ó The Japanese Association for Thoracic Surgery 2013
Abstract Objective Chordal placement with no or minimal leaflet resection has been suggested as the preferred technique for mitral valve repair for posterior leaflet prolapse, because it creates a longer coaptation zone. However, whether or not a long coaptation zone improves the durability of mitral valve repairs remains unclear. Methods We reviewed 119 patients with chronic degenerative mitral regurgitation including posterior middle scallop prolapse who underwent mitral valve repair between June 2004 and July 2008. We divided them into two groups according to post-repair coaptation length C8 mm (group A) or \8 mm (group B). We assessed whether coaptation length is associated with recurrent mitral regurgitation at 1 year after surgery and increase in the regurgitant jet area over 1 year. Results The group A had a lower incidence of recurrent mitral regurgitation (4.7 vs 9.2 %, p = 0.30), smaller increase in mitral regurgitant jet area over 1 year (0.29 vs
T. Uchimuro M. Tabata (&) T. Fukui H. Kasegawa S. Takanashi Department of Cardiovascular Surgery, Sakakibara Heart Institute, 3-16-1 Asahi-Cho, Fuchu, Tokyo 183-0033, Japan e-mail: [email protected] K. Saito Department of Cardiology, Sakakibara Heart Institute, Tokyo, Japan K. Shibayama H. Watanabe Department of Cardiology, Tokyo Bay Urayasu Ichikawa Medical Center, Chiba, Japan T. Shimokawa Department of Cardiovascular Surgery, Teikyo University School of Medicine, Tokyo, Japan
0.40 cm2, p = 0.43), and higher 5-year freedom from recurrent mitral regurgitation (85.6 vs 76.1 %, p = 0.76), although the differences were not statistically significant. The multivariate analysis showed that large coaptation length tends to be associated with decreased recurrent mitral regurgitation at 1 year (odds ratio 0.02, 95 % confidence interval 0.00–3.67, p = 0.14). Conclusions This study did not confirm the association between coaptation length and durability of mitral valve repair for posterior middle scallop prolapse. However, there was a trend towards decreased recurrent mitral regurgitation with larger coaptation length. Keywords Echocardiography Mitral valve repair Degenerative mitral valve disease
Introduction Mitral valve repair (MVR) is the gold standard for severe degenerative mitral regurgitation (MR). Resection of the prolapsed leaflet has been widely performed and has shown excellent outcomes for posterior leaflet prolapse. The concept of leaflet preservation has become increasingly appreciated [1]. Falk et al. found that chordal placement with minimal or no leaflet resection may contribute to better durability of MVR compared with leaflet resection, because of a longer zone of coaptation [2]. Post-repair coaptation length (CL) has been shown to be related to durability of MVR in patients with ischemic MR [3]. However, the association between post-repair CL and durability of MVR in degenerative MR has not been investigated. In this study, we aimed to assess the association between post-repair CL and durability of MVR in patients with degenerative MR, including posterior middle scallop prolapse. Our hypothesis
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was that a larger post-repair CL contributes to the prevention of recurrent MR at 1 year and a smaller increase in mitral regurgitant jet area (MRA) over 1 year after surgery.
Materials and methods Subjects and study design A total of 135 patients with severe chronic MR including isolated posterior leaflet prolapse underwent MVR at our hospital between June 2004 and July 2008. We did not include patients with acute mitral regurgitation, isolated anterior leaflet prolapse, posterior leaflet/bileaflet prolapse without posterior middle scallop prolapse or Barlow’s disease from this study. All patients received pre-operative and post-operative transthoracic echocardiograms (TTE), and 125 patients had a 1-year follow-up TTE. We excluded six patients with mild MR on post-operative TTE and 10 patients with no 1-year follow-up TTE, and we reviewed the operative and echocardiographic data of the remaining 119 patients. We assessed the association between postrepair CL and recurrent mild or greater MR at 1-year, and the difference in MRA during the 1-year follow-up period. We divided the 119 patients into two groups according to post-repair CL: 43 patients had a CL C8 mm (group A) and 76 patients had a CL \8 mm (group B). The cut-off length of 8 mm was based on previous studies that recommended a minimum CL of 8 mm after repair of ischemic MR [3, 4]. This study was approved by the institutional review board of Sakakibara Heart Institute, and a waiver of informed consent was obtained. Operative procedure All operations included in this study were performed via a median sternotomy approach. Cardiopulmonary bypass was established by ascending aortic and bicaval cannulation. The aorta was cross-clamped and cardiac asystole was achieved using intermittent antegrade and retrograde cardioplegia. Posterior leaflet prolapse was primarily repaired by leaflet resection. The resection size and shape were determined by a surgeon in charge of each case. Neochordal placement was added if necessary. Ring annuloplasty was performed in all cases. The type of ring was chosen based on surgeon’s preference. The size of ring was determined by sizing the area of anterior leaflet using prosthetic sizers made by each manufacturer.
1 year after surgery or later. All echocardiographic exams were performed by well-trained echocardiographic technicians and reviewed by an echocardiologist (H.W.) and technician (K.S.). We measured CL, coaptation depth (CD), and MRA (Fig. 1). CL was defined as the length of the coaptation zone of the anterior and posterior leaflets at the level of the middle scallops. CD was defined as the perpendicular distance from the annular plane to the highest coaptation point. MRA was defined as the area of color Doppler regurgitant jet at early to mid-systolic phase. These parameters were measured in apical three-chamber view. The severity of MR was determined according to the ACC/AHA 2006 Guidelines [5]. Sub-analysis by operative technique We divided the patients into two groups according to operative technique: resection without neochordal placement group (group R, n = 93) and neochordal placement group (group N, n = 26), and compared the echocardiographic findings and incidences of recurrent MR between two groups. Statistical analysis All statistical analyses were performed using IBM SPSS version 19 (IBM, Armonk, NY, USA). Continuous values were expressed as mean ± standard deviation, and were compared by unpaired or paired t tests as appropriate. Categorical variables were compared using v2 or Fisher’s exact tests as appropriate. All comparisons were planned and the tests were two-sided. A p value of \0.05 was considered statistically significant. Multivariate logistic and linear regression models were used to assess the associations between CL and recurrence of mild or greater MR and increase in MRA over 1 year post-operation. The covariates in the models included age, hypertension, atrial fibrillation, pre-operative left ventricular ejection fraction (LVEF), operative technique, and postrepair CD. We selected these covariates as potential confounding factors based on previous findings [3, 6, 7]. We applied multivariate models with post-repair CL as a continuous variable without dichotomization to ensure that the results were not influenced by the cut-off value of 8 mm. Kaplan–Meier analysis was used to estimate long-term survival and freedom from mild or greater MR.
Results
Echocardiographic study
Pre-operative and operative data
Post-operative TTE was performed 4–7 days after surgery and before discharge. A follow-up TTE was performed at
The mean age of all patients was 58.4 ± 11.8 years and 38 patients (31.9 %) were women. All patients had a posterior
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Fig. 1 Echocardiographic measurements in the apical three-chamber view. a CL and CD. b MRA. CL coaptation length, CD coaptation depth, MRA mitral regurgitant jet area Table 1 Pre-operative patient characteristics, echocardiographic data, and operative techniques
Table 2 Post-operative and 1-year echocardiographic data Variable
Group A (n = 43)
Group B (n = 76)
p value
Variable
Group A (n = 43)
Group B (n = 76)
p value
Age (years)
57.6 ± 12.9
58.8 ± 11.2
0.61
Female n (%)
11 (25.6)
27 (35.5)
0.26
NYHA class III or IV n (%)
12 (27.9)
18 (23.7)
0.61
LVEDD (mm)
47.8 ± 7.1
47.6 ± 6.0
0.92
LVEF (%)
65.3 ± 6.6
66.3 ± 7.3
0.46
LVESD (mm)
34.4 ± 7.3
33.4 ± 5.9
0.43
Post-operative echocardiographic data LVEF (%) LAD (mm)
53.1 ± 11.1 39.1 ± 7.3
54.6 ± 7.9 39.8 ± 5.7
0.41 0.57
LAD (mm)
45.2 ± 8.0
46.7 ± 6.7
0.27
CL (mm)
9.9 ± 1.8
6.7 ± 0.8
\0.01
LVEDD (mm)
55.2 ± 7.4
56.2 ± 5.6
0.42
CD (mm)
2.3 ± 2.0
3.4 ± 1.7
\0.01
MRA (cm2)
0.22 ± 0.37
0.27 ± 0.41
LVESD (mm)
35.3 ± 7.0
34.7 ± 6.0
0.62
Posterior leaflet resection n (%)
43 (100)
75 (98.7)
0.64
Posterior neochordal placement n (%)
10 (23.3)
16 (21.1)
0.78
NYHA New York Heart Association, LVEF left ventricular ejection fraction, LAD left atrial diameter, LVEDD left ventricular end-diastolic diameter, LVESD left ventricular end-systolic diameter
middle scallop prolapse, 30 patients (25.2 %) demonstrated NYHA class III or IV heart failure, and the mean LVEF was 65.9 ± 7.1 %. All patients underwent ring or band annuloplasty, 118 (99.2 %) underwent posterior leaflet resection, and 26 (21.8 %) had posterior neochordal placement. Pre-operative and operative data for each group are shown in Table 1. There were no significant differences between the two groups. Post-operative echocardiographic findings All patients presented with no or trivial MR on postoperative TTE. The mean CL was 7.8 ± 2.0 mm, the mean CD was 3.0 ± 1.9 mm, and the mean MRA was 0.25 ± 0.39 cm2. The mean CD was significantly smaller in group A than group B.
0.53
1-year echocardiographic data LVEF (%)
57.8 ± 7.4
59.2 ± 7.3
0.30
LAD (mm)
37.7 ± 6.7
39.2 ± 6.2
0.22
LVEDD (mm)
44.9 ± 5.7
45.2 ± 5.1
0.78
LVESD (mm)
30.5 ± 5.9
30.0 ± 6.0
CL (mm)
8.2 ± 2.3
6.3 ± 1.4
\0.01
0.69
Change in CL over 1 year (mm)
-1.7 ± 2.2
-0.3 ± 1.3
\0.01
CD (mm)
2.4 ± 1.9
3.5 ± 1.7
\0.01
Change in CD over 1 year (mm)
0.1 ± 1.8
0.2 ± 1.9
0.85
MRA (cm2)
0.51 ± 0.58
0.67 ± 0.78
0.24
Change in MRA over 1 year (cm2)
0.29 ± 0.59
0.40 ± 0.82
0.43
Recurrent mild or greater MR n (%)
2 (4.7)
7 (9.2)
0.30
LVEF left ventricular ejection fraction, LAD left atrial diameter, LVEDD left ventricular end-diastolic diameter, LVESD left ventricular end-systolic diameter, CL coaptation length, CD coaptation depth, MRA mitral regurgitant jet area, MR mitral regurgitation
One-year echocardiographic findings Nine patients (7.6 %) presented with recurrent mild MR on 1-year TTE. No patients had moderate or severe MR and no patients required mitral valve reoperation. The post-
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Fig. 2 Post-operative and 1-year echocardiographic variables, showing 95 % confidence intervals. a Left ventricular ejection fraction (mm). b Left ventricular end-diastolic diameter (mm). c Left ventricular end-systolic diameter (mm). d Left ventricular end-
systolic diameter/left ventricular end-diastolic diameter. e Coaptation length (mm). f Coaptation depth (mm). g Mitral regurgitant jet area (cm2)
operative and 1-year TTE findings in each group are shown in Table 2. The group A tended to have a lower incidence of recurrent MR and smaller increase in MRA although the differences were not statistically significant. The differences in left ventricular dimensions, CL, CD, and MRA over 1 year are shown in Fig. 2. Both groups showed significant decreases in left ventricular dimensions and significant increases in LVEF over 1 year. The mean 1-year CL was 7.0 ± 2.0 mm, which was significantly smaller than the post-repair CL (p \ 0.01). The mean 1-year CD was 3.1 ± 1.9 mm, which was similar to the post-repair CD (p = 0.42). The mean 1-year MRA was 0.61 ± 0.71 cm2, which was significantly larger than the post-repair MRA (p \ 0.01). Mean CL was significantly reduced (p \ 0.01 and p = 0.03 in groups A and B, respectively), mean CD remained unchanged (p = 0.72
and p = 0.46 in groups A and B, respectively), and mean MRA was significantly increased (both p \ 0.01) over 1 year post-operation. The increases in MRA were similar in both groups (p = 0.43). Multiple logistic regression analysis showed no significant associations between CL and recurrent mild MR and increase in MRA over 1 year. However, there was a trend towards decreased recurrent mild MR with larger CL (odds ratio 0.02; 95 % confidence interval 0.00–3.67; p = 0.14) (Table 3). We reviewed the echocardiographic findings in nine cases with recurrent mild MR. We found no recurrent prolapsed but high echoic change and poor mobility of the posterior middle scallop in six cases (2 in group A and 4 in group B), and poor coaptation despite normal leaflet position and motion in the other three cases in group B.
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Gen Thorac Cardiovasc Surg Table 3 Multivariate analysis of factors associated with increasing mitral regurgitation over 1 year after surgery Recurrent MR Cmild at 1 year
Increasing MRA during 1 year
Variable
OR
95 % CI
p value
OR
95 % CI
p value
Post-repair CL
0.02
0.00–3.67
0.14
0.24
0.03–2.04
0.19
Post-repair CD
0.34
0.00–26.24
0.63
1.12
0.11–11.86
0.93
Age
1.02
0.95–1.09
0.64
0.97
0.94–1.01
0.13
Hypertension
7.69
0.82–71.98
0.07
1.60
0.71–3.59
0.25
Atrial fibrillation
0.63
0.04–8.88
0.73
1.29
0.36–4.63
0.70
Pre-operative LVEF
0.99
0.88–1.12
0.93
0.97
0.92–1.03
0.39
Neochordal placement Use of flexible ring
0.51 2.14
0.10–2.55 0.23–19.81
0.41 0.50
0.78 0.70
0.30–2.04 0.25–1.96
0.61 0.50
MR mitral regurgitation, MRA mitral regurgitant jet area, OR odds ratio, CI confidence intervals, CL coaptation length, CD coaptation depth, LVEF left ventricular ejection fraction
Fig. 3 Kaplan Meier curves for freedom from recurrent mild or greater mitral regurgitation. a Group A (post-repair coaptation length C8 mm) vs Group B (post-repair coaptation length \8 mm). b Group R (resection only) vs Group N (neochordal placement)
Echocardiographic findings at C1 year after surgery The mean duration of echocardiographic follow-up was 36.4 ± 24.2 months. There was no significant difference in 5-year freedom from recurrent MR between groups A and B (85.6 ± 6.2 vs 76.1 ± 7.2 %, respectively, p = 0.76) (Fig. 3a).
after surgery or 1 year after surgery (Table 4). The incidences of mild or greater MR at 1 year were 6.5 % (n = 6) in group R and 11.5 % (n = 3) in group N (p = 0.31). There was no significant difference in 5-year freedom from mild or greater MR between groups R and N (76.1 ± 6.7 and 88.3 ± 6.4 %, p = 0.81) (Fig. 3b).
Sub-analysis by operative technique
Discussion
There were no significant differences in LV dimension, CL, CD, and MRA between the two groups immediately
Previous studies have compared operative outcomes between different valvular pathologies and surgical
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Gen Thorac Cardiovasc Surg Table 4 Sub-group analysis according to surgical procedure Variable
Group R (n = 93)
Group N (n = 26)
p value
Post-operative echocardiographic data LVEF (%)
54.0 ± 9.1
54.5 ± 9.7
0.81
LVEDD (mm)
47.4 ± 6.5
48.8 ± 5.7
0.31
LVESD (mm)
33.5 ± 6.6
34.6 ± 5.7
0.45
CL (mm)
7.8 ± 1.9
8.0 ± 0.3
0.68
2.8 ± 1.9
3.5 ± 1.8
0.10
0.35 ± 0.53
0.27
CD (mm) 2
MRA (cm ) 0.23 ± 0.35 1-year echocardiographic data LVEF (%)
59.3 ± 7.1
56.7 ± 8.2
0.12
LVEDD (mm)
44.9 ± 5.3
45.9 ± 5.3
0.39
Change in LVEDD over 1 year (mm)
-2.5 ± 4.4
-2.9 ± 4.2
0.67
LVESD (mm)
30.0 ± 5.9
31.4 ± 5.9
0.25
Change in LVESD over 1 year (mm)
-3.6 ± 5.6
-3.2 ± 4.3
0.72
CL (mm) Change in CL over 1 year (mm)
6.9 ± 1.8 -0.8 ± 1.8
7.2 ± 2.4 -0.7 ± 1.9
0.52 0.81
CD (mm)
3.1 ± 1.9
3.3 ± 1.6
0.62
Change in CD over 1 year (mm)
0.2 ± 2.0
-0.2 ± 1.4
0.27
MRA (cm2)
0.59 ± 0.70
0.68 ± 0.77
0.56
Change in MRA over 1 year (cm2)
0.36 ± 0.70
0.33 ± 0.88
0.85
MR Cmild recurrence n (%)
6 (6.5)
3 (11.5)
0.31
LVEF left ventricular ejection fraction, LVEDD left ventricular enddiastolic diameter, LVESD left ventricular end-systolic diameter, CL coaptation length, CD coaptation depth, MRA mitral regurgitant jet area, MR mitral regurgitation
procedures in degenerative mitral valve disease. Anterior leaflet prolapse and bileaflet prolapse have been shown to be predictors of poor durability of MVR [8, 9]. Another study has shown that outcomes of MVR in Barlow disease are similar to those in fibroelastic deficiency, provided optimal surgical techniques are used [10]. Regarding the surgical procedure, MVR without ring annuloplasty has been shown to be associated with recurrent MR [11]. Neochordal placement without leaflet resection and conventional leaflet resection has been shown to have similar excellent results in patients with posterior leaflet prolapse [2, 6]. However, the post-repair valvular configuration can vary widely depending on the original leaflet height, leaflet resection area, length of the neochordae, and selected size and type of annuloplasty ring, even when the same technique is used for the same pathology. We, therefore, focused on the post-repair valvular configuration, rather than on valvular pathology and surgical techniques in this study.
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In our study, large CL tended to be associated with a lower incidence of recurrent MR (p = 0.30), a smaller increase in MRA over 1 year (p = 0.43), and higher 5-year freedom from recurrent mild or greater MR (p = 0.76), though the differences were not significant. Echocardiographic findings in 9 patients with mild or greater MR recurrence showed that advanced degenerative change in the posterior leaflet was possibly a primary cause of recurrence. Large CL may thus ensure sustained coaptation even after progression of degenerative changes. In the subgroup analysis, neochordal replacement group tended to have a higher incidence of recurrent MR than resection without neochordal replacement group although the difference was not statistically significant. During this series, our first choice was leaflet resection for the posterior leaflet prolapsed and we added neochordal replacement if the isolated resection is not enough. Thus, this result might be because of the difference in complexity of pre-operative valvular pathology. In our more recent series, we more frequently use neochordal replacement without leaflet resection for posterior prolapse to create a larger CL after MVR unless the leaflet per se is damaged. There are some limitations of this study, which is associated with its retrospective and observational natures. MRA has limited use for evaluating the severity of MR with eccentric jets [12]. The reliability of MRA as an outcome measure might not be a very robust. Regurgitant volume, regurgitant fraction, or regurgitant orifice area are more precise quantitative parameters of MR than MRA, but are difficult to measure in cases of trivial MR. To minimize biases and maximize reproducibility, all MRAs were measured by one technician (K.S.) who was blinded to the purpose of the study at the time of measurement. In addition, the small sample size may have contributed to failure of statistical confirmation of the association between postrepair CL and durability of MVR. In conclusion, this study found no significant association between CL and recurrence of MR or increase in MRA during a 1-year period after MVR for chronic degenerative MR, including posterior middle scallop prolapse. However, there was a trend towards decreased recurrence of MR with larger post-repair CL. Further studies with larger follow-up periods and larger sample sizes are needed to clarify these relationships. Conflict of interest interest exists.
The authors have declared that no conflict of
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ORIGINAL ARTICLE
Post-repair coaptation length and durability of mitral valve repair for posterior mitral valve prolapse Tomoya Uchimuro • Minoru Tabata • Kiyomi Saito • Kentaro Shibayama • Hiroyuki Watanabe • Toshihiro Fukui • Tomoki Shimokawa • Hitoshi Kasegawa • Shuichiro Takanashi
Received: 18 January 2013 / Accepted: 29 October 2013 Ó The Japanese Association for Thoracic Surgery 2013
Abstract Objective Chordal placement with no or minimal leaflet resection has been suggested as the preferred technique for mitral valve repair for posterior leaflet prolapse, because it creates a longer coaptation zone. However, whether or not a long coaptation zone improves the durability of mitral valve repairs remains unclear. Methods We reviewed 119 patients with chronic degenerative mitral regurgitation including posterior middle scallop prolapse who underwent mitral valve repair between June 2004 and July 2008. We divided them into two groups according to post-repair coaptation length C8 mm (group A) or \8 mm (group B). We assessed whether coaptation length is associated with recurrent mitral regurgitation at 1 year after surgery and increase in the regurgitant jet area over 1 year. Results The group A had a lower incidence of recurrent mitral regurgitation (4.7 vs 9.2 %, p = 0.30), smaller increase in mitral regurgitant jet area over 1 year (0.29 vs
T. Uchimuro M. Tabata (&) T. Fukui H. Kasegawa S. Takanashi Department of Cardiovascular Surgery, Sakakibara Heart Institute, 3-16-1 Asahi-Cho, Fuchu, Tokyo 183-0033, Japan e-mail: [email protected] K. Saito Department of Cardiology, Sakakibara Heart Institute, Tokyo, Japan K. Shibayama H. Watanabe Department of Cardiology, Tokyo Bay Urayasu Ichikawa Medical Center, Chiba, Japan T. Shimokawa Department of Cardiovascular Surgery, Teikyo University School of Medicine, Tokyo, Japan
0.40 cm2, p = 0.43), and higher 5-year freedom from recurrent mitral regurgitation (85.6 vs 76.1 %, p = 0.76), although the differences were not statistically significant. The multivariate analysis showed that large coaptation length tends to be associated with decreased recurrent mitral regurgitation at 1 year (odds ratio 0.02, 95 % confidence interval 0.00–3.67, p = 0.14). Conclusions This study did not confirm the association between coaptation length and durability of mitral valve repair for posterior middle scallop prolapse. However, there was a trend towards decreased recurrent mitral regurgitation with larger coaptation length. Keywords Echocardiography Mitral valve repair Degenerative mitral valve disease
Introduction Mitral valve repair (MVR) is the gold standard for severe degenerative mitral regurgitation (MR). Resection of the prolapsed leaflet has been widely performed and has shown excellent outcomes for posterior leaflet prolapse. The concept of leaflet preservation has become increasingly appreciated [1]. Falk et al. found that chordal placement with minimal or no leaflet resection may contribute to better durability of MVR compared with leaflet resection, because of a longer zone of coaptation [2]. Post-repair coaptation length (CL) has been shown to be related to durability of MVR in patients with ischemic MR [3]. However, the association between post-repair CL and durability of MVR in degenerative MR has not been investigated. In this study, we aimed to assess the association between post-repair CL and durability of MVR in patients with degenerative MR, including posterior middle scallop prolapse. Our hypothesis
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was that a larger post-repair CL contributes to the prevention of recurrent MR at 1 year and a smaller increase in mitral regurgitant jet area (MRA) over 1 year after surgery.
Materials and methods Subjects and study design A total of 135 patients with severe chronic MR including isolated posterior leaflet prolapse underwent MVR at our hospital between June 2004 and July 2008. We did not include patients with acute mitral regurgitation, isolated anterior leaflet prolapse, posterior leaflet/bileaflet prolapse without posterior middle scallop prolapse or Barlow’s disease from this study. All patients received pre-operative and post-operative transthoracic echocardiograms (TTE), and 125 patients had a 1-year follow-up TTE. We excluded six patients with mild MR on post-operative TTE and 10 patients with no 1-year follow-up TTE, and we reviewed the operative and echocardiographic data of the remaining 119 patients. We assessed the association between postrepair CL and recurrent mild or greater MR at 1-year, and the difference in MRA during the 1-year follow-up period. We divided the 119 patients into two groups according to post-repair CL: 43 patients had a CL C8 mm (group A) and 76 patients had a CL \8 mm (group B). The cut-off length of 8 mm was based on previous studies that recommended a minimum CL of 8 mm after repair of ischemic MR [3, 4]. This study was approved by the institutional review board of Sakakibara Heart Institute, and a waiver of informed consent was obtained. Operative procedure All operations included in this study were performed via a median sternotomy approach. Cardiopulmonary bypass was established by ascending aortic and bicaval cannulation. The aorta was cross-clamped and cardiac asystole was achieved using intermittent antegrade and retrograde cardioplegia. Posterior leaflet prolapse was primarily repaired by leaflet resection. The resection size and shape were determined by a surgeon in charge of each case. Neochordal placement was added if necessary. Ring annuloplasty was performed in all cases. The type of ring was chosen based on surgeon’s preference. The size of ring was determined by sizing the area of anterior leaflet using prosthetic sizers made by each manufacturer.
1 year after surgery or later. All echocardiographic exams were performed by well-trained echocardiographic technicians and reviewed by an echocardiologist (H.W.) and technician (K.S.). We measured CL, coaptation depth (CD), and MRA (Fig. 1). CL was defined as the length of the coaptation zone of the anterior and posterior leaflets at the level of the middle scallops. CD was defined as the perpendicular distance from the annular plane to the highest coaptation point. MRA was defined as the area of color Doppler regurgitant jet at early to mid-systolic phase. These parameters were measured in apical three-chamber view. The severity of MR was determined according to the ACC/AHA 2006 Guidelines [5]. Sub-analysis by operative technique We divided the patients into two groups according to operative technique: resection without neochordal placement group (group R, n = 93) and neochordal placement group (group N, n = 26), and compared the echocardiographic findings and incidences of recurrent MR between two groups. Statistical analysis All statistical analyses were performed using IBM SPSS version 19 (IBM, Armonk, NY, USA). Continuous values were expressed as mean ± standard deviation, and were compared by unpaired or paired t tests as appropriate. Categorical variables were compared using v2 or Fisher’s exact tests as appropriate. All comparisons were planned and the tests were two-sided. A p value of \0.05 was considered statistically significant. Multivariate logistic and linear regression models were used to assess the associations between CL and recurrence of mild or greater MR and increase in MRA over 1 year post-operation. The covariates in the models included age, hypertension, atrial fibrillation, pre-operative left ventricular ejection fraction (LVEF), operative technique, and postrepair CD. We selected these covariates as potential confounding factors based on previous findings [3, 6, 7]. We applied multivariate models with post-repair CL as a continuous variable without dichotomization to ensure that the results were not influenced by the cut-off value of 8 mm. Kaplan–Meier analysis was used to estimate long-term survival and freedom from mild or greater MR.
Results
Echocardiographic study
Pre-operative and operative data
Post-operative TTE was performed 4–7 days after surgery and before discharge. A follow-up TTE was performed at
The mean age of all patients was 58.4 ± 11.8 years and 38 patients (31.9 %) were women. All patients had a posterior
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Fig. 1 Echocardiographic measurements in the apical three-chamber view. a CL and CD. b MRA. CL coaptation length, CD coaptation depth, MRA mitral regurgitant jet area Table 1 Pre-operative patient characteristics, echocardiographic data, and operative techniques
Table 2 Post-operative and 1-year echocardiographic data Variable
Group A (n = 43)
Group B (n = 76)
p value
Variable
Group A (n = 43)
Group B (n = 76)
p value
Age (years)
57.6 ± 12.9
58.8 ± 11.2
0.61
Female n (%)
11 (25.6)
27 (35.5)
0.26
NYHA class III or IV n (%)
12 (27.9)
18 (23.7)
0.61
LVEDD (mm)
47.8 ± 7.1
47.6 ± 6.0
0.92
LVEF (%)
65.3 ± 6.6
66.3 ± 7.3
0.46
LVESD (mm)
34.4 ± 7.3
33.4 ± 5.9
0.43
Post-operative echocardiographic data LVEF (%) LAD (mm)
53.1 ± 11.1 39.1 ± 7.3
54.6 ± 7.9 39.8 ± 5.7
0.41 0.57
LAD (mm)
45.2 ± 8.0
46.7 ± 6.7
0.27
CL (mm)
9.9 ± 1.8
6.7 ± 0.8
\0.01
LVEDD (mm)
55.2 ± 7.4
56.2 ± 5.6
0.42
CD (mm)
2.3 ± 2.0
3.4 ± 1.7
\0.01
MRA (cm2)
0.22 ± 0.37
0.27 ± 0.41
LVESD (mm)
35.3 ± 7.0
34.7 ± 6.0
0.62
Posterior leaflet resection n (%)
43 (100)
75 (98.7)
0.64
Posterior neochordal placement n (%)
10 (23.3)
16 (21.1)
0.78
NYHA New York Heart Association, LVEF left ventricular ejection fraction, LAD left atrial diameter, LVEDD left ventricular end-diastolic diameter, LVESD left ventricular end-systolic diameter
middle scallop prolapse, 30 patients (25.2 %) demonstrated NYHA class III or IV heart failure, and the mean LVEF was 65.9 ± 7.1 %. All patients underwent ring or band annuloplasty, 118 (99.2 %) underwent posterior leaflet resection, and 26 (21.8 %) had posterior neochordal placement. Pre-operative and operative data for each group are shown in Table 1. There were no significant differences between the two groups. Post-operative echocardiographic findings All patients presented with no or trivial MR on postoperative TTE. The mean CL was 7.8 ± 2.0 mm, the mean CD was 3.0 ± 1.9 mm, and the mean MRA was 0.25 ± 0.39 cm2. The mean CD was significantly smaller in group A than group B.
0.53
1-year echocardiographic data LVEF (%)
57.8 ± 7.4
59.2 ± 7.3
0.30
LAD (mm)
37.7 ± 6.7
39.2 ± 6.2
0.22
LVEDD (mm)
44.9 ± 5.7
45.2 ± 5.1
0.78
LVESD (mm)
30.5 ± 5.9
30.0 ± 6.0
CL (mm)
8.2 ± 2.3
6.3 ± 1.4
\0.01
0.69
Change in CL over 1 year (mm)
-1.7 ± 2.2
-0.3 ± 1.3
\0.01
CD (mm)
2.4 ± 1.9
3.5 ± 1.7
\0.01
Change in CD over 1 year (mm)
0.1 ± 1.8
0.2 ± 1.9
0.85
MRA (cm2)
0.51 ± 0.58
0.67 ± 0.78
0.24
Change in MRA over 1 year (cm2)
0.29 ± 0.59
0.40 ± 0.82
0.43
Recurrent mild or greater MR n (%)
2 (4.7)
7 (9.2)
0.30
LVEF left ventricular ejection fraction, LAD left atrial diameter, LVEDD left ventricular end-diastolic diameter, LVESD left ventricular end-systolic diameter, CL coaptation length, CD coaptation depth, MRA mitral regurgitant jet area, MR mitral regurgitation
One-year echocardiographic findings Nine patients (7.6 %) presented with recurrent mild MR on 1-year TTE. No patients had moderate or severe MR and no patients required mitral valve reoperation. The post-
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Fig. 2 Post-operative and 1-year echocardiographic variables, showing 95 % confidence intervals. a Left ventricular ejection fraction (mm). b Left ventricular end-diastolic diameter (mm). c Left ventricular end-systolic diameter (mm). d Left ventricular end-
systolic diameter/left ventricular end-diastolic diameter. e Coaptation length (mm). f Coaptation depth (mm). g Mitral regurgitant jet area (cm2)
operative and 1-year TTE findings in each group are shown in Table 2. The group A tended to have a lower incidence of recurrent MR and smaller increase in MRA although the differences were not statistically significant. The differences in left ventricular dimensions, CL, CD, and MRA over 1 year are shown in Fig. 2. Both groups showed significant decreases in left ventricular dimensions and significant increases in LVEF over 1 year. The mean 1-year CL was 7.0 ± 2.0 mm, which was significantly smaller than the post-repair CL (p \ 0.01). The mean 1-year CD was 3.1 ± 1.9 mm, which was similar to the post-repair CD (p = 0.42). The mean 1-year MRA was 0.61 ± 0.71 cm2, which was significantly larger than the post-repair MRA (p \ 0.01). Mean CL was significantly reduced (p \ 0.01 and p = 0.03 in groups A and B, respectively), mean CD remained unchanged (p = 0.72
and p = 0.46 in groups A and B, respectively), and mean MRA was significantly increased (both p \ 0.01) over 1 year post-operation. The increases in MRA were similar in both groups (p = 0.43). Multiple logistic regression analysis showed no significant associations between CL and recurrent mild MR and increase in MRA over 1 year. However, there was a trend towards decreased recurrent mild MR with larger CL (odds ratio 0.02; 95 % confidence interval 0.00–3.67; p = 0.14) (Table 3). We reviewed the echocardiographic findings in nine cases with recurrent mild MR. We found no recurrent prolapsed but high echoic change and poor mobility of the posterior middle scallop in six cases (2 in group A and 4 in group B), and poor coaptation despite normal leaflet position and motion in the other three cases in group B.
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Gen Thorac Cardiovasc Surg Table 3 Multivariate analysis of factors associated with increasing mitral regurgitation over 1 year after surgery Recurrent MR Cmild at 1 year
Increasing MRA during 1 year
Variable
OR
95 % CI
p value
OR
95 % CI
p value
Post-repair CL
0.02
0.00–3.67
0.14
0.24
0.03–2.04
0.19
Post-repair CD
0.34
0.00–26.24
0.63
1.12
0.11–11.86
0.93
Age
1.02
0.95–1.09
0.64
0.97
0.94–1.01
0.13
Hypertension
7.69
0.82–71.98
0.07
1.60
0.71–3.59
0.25
Atrial fibrillation
0.63
0.04–8.88
0.73
1.29
0.36–4.63
0.70
Pre-operative LVEF
0.99
0.88–1.12
0.93
0.97
0.92–1.03
0.39
Neochordal placement Use of flexible ring
0.51 2.14
0.10–2.55 0.23–19.81
0.41 0.50
0.78 0.70
0.30–2.04 0.25–1.96
0.61 0.50
MR mitral regurgitation, MRA mitral regurgitant jet area, OR odds ratio, CI confidence intervals, CL coaptation length, CD coaptation depth, LVEF left ventricular ejection fraction
Fig. 3 Kaplan Meier curves for freedom from recurrent mild or greater mitral regurgitation. a Group A (post-repair coaptation length C8 mm) vs Group B (post-repair coaptation length \8 mm). b Group R (resection only) vs Group N (neochordal placement)
Echocardiographic findings at C1 year after surgery The mean duration of echocardiographic follow-up was 36.4 ± 24.2 months. There was no significant difference in 5-year freedom from recurrent MR between groups A and B (85.6 ± 6.2 vs 76.1 ± 7.2 %, respectively, p = 0.76) (Fig. 3a).
after surgery or 1 year after surgery (Table 4). The incidences of mild or greater MR at 1 year were 6.5 % (n = 6) in group R and 11.5 % (n = 3) in group N (p = 0.31). There was no significant difference in 5-year freedom from mild or greater MR between groups R and N (76.1 ± 6.7 and 88.3 ± 6.4 %, p = 0.81) (Fig. 3b).
Sub-analysis by operative technique
Discussion
There were no significant differences in LV dimension, CL, CD, and MRA between the two groups immediately
Previous studies have compared operative outcomes between different valvular pathologies and surgical
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Gen Thorac Cardiovasc Surg Table 4 Sub-group analysis according to surgical procedure Variable
Group R (n = 93)
Group N (n = 26)
p value
Post-operative echocardiographic data LVEF (%)
54.0 ± 9.1
54.5 ± 9.7
0.81
LVEDD (mm)
47.4 ± 6.5
48.8 ± 5.7
0.31
LVESD (mm)
33.5 ± 6.6
34.6 ± 5.7
0.45
CL (mm)
7.8 ± 1.9
8.0 ± 0.3
0.68
2.8 ± 1.9
3.5 ± 1.8
0.10
0.35 ± 0.53
0.27
CD (mm) 2
MRA (cm ) 0.23 ± 0.35 1-year echocardiographic data LVEF (%)
59.3 ± 7.1
56.7 ± 8.2
0.12
LVEDD (mm)
44.9 ± 5.3
45.9 ± 5.3
0.39
Change in LVEDD over 1 year (mm)
-2.5 ± 4.4
-2.9 ± 4.2
0.67
LVESD (mm)
30.0 ± 5.9
31.4 ± 5.9
0.25
Change in LVESD over 1 year (mm)
-3.6 ± 5.6
-3.2 ± 4.3
0.72
CL (mm) Change in CL over 1 year (mm)
6.9 ± 1.8 -0.8 ± 1.8
7.2 ± 2.4 -0.7 ± 1.9
0.52 0.81
CD (mm)
3.1 ± 1.9
3.3 ± 1.6
0.62
Change in CD over 1 year (mm)
0.2 ± 2.0
-0.2 ± 1.4
0.27
MRA (cm2)
0.59 ± 0.70
0.68 ± 0.77
0.56
Change in MRA over 1 year (cm2)
0.36 ± 0.70
0.33 ± 0.88
0.85
MR Cmild recurrence n (%)
6 (6.5)
3 (11.5)
0.31
LVEF left ventricular ejection fraction, LVEDD left ventricular enddiastolic diameter, LVESD left ventricular end-systolic diameter, CL coaptation length, CD coaptation depth, MRA mitral regurgitant jet area, MR mitral regurgitation
procedures in degenerative mitral valve disease. Anterior leaflet prolapse and bileaflet prolapse have been shown to be predictors of poor durability of MVR [8, 9]. Another study has shown that outcomes of MVR in Barlow disease are similar to those in fibroelastic deficiency, provided optimal surgical techniques are used [10]. Regarding the surgical procedure, MVR without ring annuloplasty has been shown to be associated with recurrent MR [11]. Neochordal placement without leaflet resection and conventional leaflet resection has been shown to have similar excellent results in patients with posterior leaflet prolapse [2, 6]. However, the post-repair valvular configuration can vary widely depending on the original leaflet height, leaflet resection area, length of the neochordae, and selected size and type of annuloplasty ring, even when the same technique is used for the same pathology. We, therefore, focused on the post-repair valvular configuration, rather than on valvular pathology and surgical techniques in this study.
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In our study, large CL tended to be associated with a lower incidence of recurrent MR (p = 0.30), a smaller increase in MRA over 1 year (p = 0.43), and higher 5-year freedom from recurrent mild or greater MR (p = 0.76), though the differences were not significant. Echocardiographic findings in 9 patients with mild or greater MR recurrence showed that advanced degenerative change in the posterior leaflet was possibly a primary cause of recurrence. Large CL may thus ensure sustained coaptation even after progression of degenerative changes. In the subgroup analysis, neochordal replacement group tended to have a higher incidence of recurrent MR than resection without neochordal replacement group although the difference was not statistically significant. During this series, our first choice was leaflet resection for the posterior leaflet prolapsed and we added neochordal replacement if the isolated resection is not enough. Thus, this result might be because of the difference in complexity of pre-operative valvular pathology. In our more recent series, we more frequently use neochordal replacement without leaflet resection for posterior prolapse to create a larger CL after MVR unless the leaflet per se is damaged. There are some limitations of this study, which is associated with its retrospective and observational natures. MRA has limited use for evaluating the severity of MR with eccentric jets [12]. The reliability of MRA as an outcome measure might not be a very robust. Regurgitant volume, regurgitant fraction, or regurgitant orifice area are more precise quantitative parameters of MR than MRA, but are difficult to measure in cases of trivial MR. To minimize biases and maximize reproducibility, all MRAs were measured by one technician (K.S.) who was blinded to the purpose of the study at the time of measurement. In addition, the small sample size may have contributed to failure of statistical confirmation of the association between postrepair CL and durability of MVR. In conclusion, this study found no significant association between CL and recurrence of MR or increase in MRA during a 1-year period after MVR for chronic degenerative MR, including posterior middle scallop prolapse. However, there was a trend towards decreased recurrence of MR with larger post-repair CL. Further studies with larger follow-up periods and larger sample sizes are needed to clarify these relationships. Conflict of interest interest exists.
The authors have declared that no conflict of
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