Abstract
Background:
Coronary artery bypass grafting (CABG) reduces functional mitral regurgitation (MR) associated with ischemic heart disease, although the predictive factors or mechanisms of reversibility of functional MR after CABG are not fully understood.
We investigated whether mitral valve structure is associated with the outcome of functional MR after CABG.
Methods and Results:
From a consecutive series of 98 patients with mild-moderate functional MR preoperatively who underwent isolated CABG, we enrolled 66 patients who were followed up for >1 year postoperatively using echocardiography. The degree of MR was reduced in 34 patients (52%) postoperatively, in association with a lower rate of in-hospital treatment for cardiac failure in the long term, compared with the 32 patients (48%) with residual MR postoperatively. The patients with reduced MR postoperatively had longer estimated coaptation length and more anteriorly or centrally directed MR jets than those without reduced MR. On statistical analysis, the addition of estimated coaptation length and jet direction to the reported predictors (ejection fraction, left ventricular end-diastolic dimension, and tenting height) more accurately predicted changes in post-CABG MR than the reported 3 factors alone.
Conclusions:
Residual MR was associated with the emergence of congestive heart failure in the long term after CABG. A specific mitral valve structure, such as large mitral leaflet size or predominant tethering of the posterior leaflet, was a predictive factor for the reversibility of post-CABG functional MR.
Myocardial infarction (MI) in the left coronary artery territory remodels the physiology and geometry of the left ventricle (LV), changing the mitral valve (MV) structure (e.g., by dilatation of the annulus or tethering the leaflets) and consequently producing functional mitral regurgitation (MR).1–4
Functional MR is thus a clinical indicator of the LV remodeling stage. It has been suggested that functional MR directly exacerbates congestive cardiac failure in the chronic MI heart by causing fluctuation in the regurgitant volume depending on hemodynamic status. Functional MR is therefore an important therapeutic target in chronic MI,5,6
although the surgical indication or reversibility of functional MR after intervention has not been established.7–9
Functional MR may be pathologically categorized into the following: dysfunction of the posterior papillary muscle induced by regional ischemia/infarction, causing predominant tethering of the medial-sided leaflets with relatively preserved LV function; dilatation and dysfunction of the global LV, causing annular dilation and balanced tethering of the leaflets; and a mixed pathology of the 2. Revascularization therapy (e.g., coronary artery bypass grafting [CABG] for the ischemic territory) improves regional systolic function and theoretically reduces the functional MR grade regardless of pathology, although functional MR remains unchanged after CABG in a certain population presenting with poor clinical outcomes in the long term. Viability of the target myocardium has been suggested to determine the clinical impact of CABG on LV remodeling and associated functional MR, and thereby on long-term clinical outcome.10
On this basis, it has been suggested that reduced functional MR after CABG is predicted by the preoperative ejection fraction (EF), end-diastolic dimension (eDD) of the LV, and tenting height of the MV, all of which are associated with the viability of the LV myocardium. The MV structure, such as annular diameter, leaflet size, or subvalvular apparatus, however, has been suggested to be remodeled by MR.11,12
Additionally, MV structure differs in individual patients regardless of MR pathology or myocardial viability.6,13–16
Based on this, we hypothesized that MV structure may be related to dynamic changes in the severity of functional MR after CABG. To test this hypothesis, we reviewed clinical outcomes following isolated CABG in patients with functional MR preoperatively to explore the predictive factors of the reversibility of functional MR. This was carried out via thorough analysis of LV and MV structure and function.
Methods
Cohort and Data Collection
The retrospective database identified 124 coronary artery bypass surgeries in patients with coronary artery disease (CAD) and mild or more functional MR preoperatively in Osaka University Hospital between January 2002 and December 2013. Mitral annuloplasty was performed in 26 patients with moderate or severe functional MR preoperatively; isolated CABG was performed for the remaining 98 patients with mild or moderate functional MR. Of these 98 patients, 66 patients with annual clinical review and echocardiography by institutional and/or local physicians were enrolled in the present study. Medical charts and/or referral letters, including serial echocardiography, were reviewed to obtain data, which were further supplemented by telephone interviews with patients under the care of distant physicians. Data were collected between November 2014 and June 2015 after obtaining institutional review board approval.
Preoperative Cohort Characteristics
The primary indication for CABG was effort/unstable angina or acute MI associated with a proximal left anterior descending artery lesion assessed on fluoroscopy-based coronary angiography. The cohort background data, retrieved from the electronic chart, were determined according to current guidelines (Table 1).17,18
Emergency surgery was defined as a surgical procedure that could not be delayed, for which there was no alternative, and for which a delay could have resulted in death. Preoperative MR degree was mild in 53 patients (80%) and moderate in 13 patients (20%).
Table 1.
Patient Characteristics
| |
All patients
(n=66) |
| Age (years) |
70 (64–75) |
| Male |
48 (73) |
| NYHA III–IV |
12 (18) |
| Atrial fibrillation |
5 (8) |
| Emergency operation |
10 (15) |
| Off-pump CABG |
39 (59) |
| 3VD |
56 (85) |
| LMTD |
25 (38) |
| SYNTAX score |
32 (27–42) |
| Acute MI |
23 (35) |
| EF (%) |
46 (36–61) |
| EF <40% |
25 (38) |
| LVeDD (mm) |
52 (48–58) |
| LVeSD (mm) |
40 (31–48) |
| TR-PG (mmHg) |
18 (10–26) |
| MR severity |
| Mild |
53 (80) |
| Moderate |
13 (20) |
| Severe |
0 (0) |
Data given as median (IQR) or n (%). 3VD, 3-vessel disease; CABG, coronary artery bypass grafting; EF, ejection fraction; LMTD, left main trunk disease; LVeDD, left ventricular end-diastolic diameter; LVeSD, left ventricular end-systolic diameter; MI, myocardial infarction; MR, mitral regurgitation; NYHA, New York Heart Association Functional Classification; TR-PG, tricuspid regurgitation pressure gradient.
The primary procedural choice of CABG in Osaka University Hospital was consistently complete revascularization using arterial grafts, such as semi-skeletonized bilateral internal thoracic arteries and radial arteries by the off-pump approach, whereas the saphenous vein was grafted in circumflex and/or right coronary artery (RCA) lesions with moderate stenosis. Standard on-pump surgery was performed in 27 patients (41%) who were hemodynamically unsuitable for the off-pump approach.
Echocardiography
All patients were examined on standard transthoracic echocardiography within 7 days preoperatively (Table 2) and >1 year postoperatively. The median interval between surgery and postoperative echocardiography was 2.9 years (range, 1.6–5.7 years). Follow-up echocardiography was performed under stable physical condition at the outpatient echocardiographic laboratory as routine practice. Standard data, such as EF, end-systolic dimension (eSD), eDD, and tricuspid regurgitation pressure gradient (TR-PG), were collected from the official echocardiographic reports. Specific data related to MV structure or the distributions of wall motion abnormalities were analyzed off-line using representative movies of the long- and short-axis views.
Table 2.
Preoperative Mitral Valve Structure and LV Wall Motion on TTE
| |
All patients
(n=66) |
| Tenting height (mm) |
8.9 (6.9–11.0) |
| Aα (°) |
29 (22–37) |
| Pα (°) |
45 (36–52) |
| Anterior leaflet length (mm) |
29 (25–31) |
| Posterior leaflet length (mm) |
15 (12–19) |
| MAD (mm) |
30 (27–32) |
| eCL (mm) |
6.6 (4.7–9.4) |
| Jet direction |
| Anterior |
2 (2) |
| Central |
28 (42) |
| Posterior |
18 (27) |
| Hypokinetic region |
| None |
18 (27) |
| Anterior |
5 (8) |
| Inferior/Posterior/Lateral |
23 (35) |
| Global |
20 (30) |
Data given as median (IQR) or n (%). eCL, estimated coaptation length; LV, left ventricle; MAD, mitral annulus diameter; TTE, transthoracic echocardiography.
Functional MR was defined as MR with anatomically normal leaflets and intact chordae,4,19
while the severity of MR was categorized according to the American College of Cardiology/American Heart Association (ACC/AHA) guidelines 2006: mild, regurgitant orifice area <0.2 cm2, regurgitant volume, <30 mL/beat, regurgitant fraction <30%, and Doppler vena contracta width <0.3 cm; moderate, regurgitant orifice area 0.2–0.39 cm2, regurgitant volume 30–59 mL/beat, regurgitant fraction 30–49%, and Doppler vena contracta width 0.3–0.69 cm; or severe, regurgitant orifice area >0.4 cm2, regurgitant volume >60 mL/beat, regurgitant fraction >50%, and Doppler vena contracta width >0.7 cm.20
Using parasternal long-axis images, the angle between the annular plane and basal portion of the anterior leaflet (Aα) and the angle between the annular plane and posterior leaflet (Pα) were measured in the mid-systole phase to assess tethering of the anterior and posterior leaflet, respectively (Figure 1A). The mid-systole phase of the parasternal long-axis images was used to obtain tenting height and mitral annular anteroposterior diameter (MAD), which was defined as the distance from the anterior root of the anterior mitral leaflet to the posterior root of the posterior mitral leaflet. The lengths of the anterior and posterior mitral leaflets (AL and PL, respectively) were measured using the diastole phase of the parasternal long-axis images (Figure 1B). The jet direction of functional MR was classified as follows: anterior, central, or posterior (Figure 1C). Estimated coaptation length was defined according to the following formula:
The hypokinetic area of the LV was categorized into 4 areas (none; anterior; inferior/posterior/lateral; or global) from short-axis images. Wall motion function in each areas was categorized into 6 stages: normokinesis; mild hypokinesis; hypokinesis; severe hypokinesis; akinesis; and dyskinesis. We defined the alternation to normokinesis or mild hypokinesis by improvement of 2 stages or more in wall motion function as positive myocardial viability.
Statistical Analysis
Data are presented as frequencies with percentages for categorical variables, and as median (IQR) for continuous variables. Categorical variables were analyzed using the chi-squared test or Fisher’s exact test. Continuous variables were examined using the Wilcoxon rank sum test. Overall survival, cardiac event-free survival, and heart failure-free survival were estimated using the Kaplan-Meier method, and differences between groups were compared using the log-rank test. Optimal cut-off of estimated coaptation length to predict reduced MR was determined on receiver operating characteristic (ROC) curve analysis (based on a univariate logistic regression model). The optimal cut-off was defined as that providing maximum accuracy to distinguish between reduced MR and residual MR postoperatively. Correlation between tenting height and coaptation length was analyzed using Spearman’s rank correlation coefficient. The preoperative predictors of reduced functional MR were estimated on univariate and multivariate logistic regression analyses. Preoperative explanatory variables included in the analysis were age at surgery; sex; hypertension; hyperlipidemia; diabetes mellitus; insulin level; hemodialysis; chronic obstructive pulmonary disease; smoking history; serum creatinine level; peripheral arterial disease; EF; LVeDD; LVeSD; TR-PG; atrial fibrillation; 3-vessel disease; left main trunk disease; acute MI; emergency surgery; and off-pump CABG. In particular, to explore new predictive factors of reduced MR after CABG, multivariable logistic regression models with penalized maximum likelihood estimations were used to evaluate the associations between these variables and the outcome while controlling for model overfitting.21–23
Moreover, we evaluated the performance of the new predictive model using integrated discrimination improvement (IDI). Statistical analysis was performed using JMP®
11 (SAS Institute, Cary, NC, USA) and R version 3.3.1 (R Foundation for Statistical Computing, Vienna, Austria). Statistical significance was defined as P<0.05.
Results
Functional MR and Associated Long-Term Clinical Outcomes of CABG
On the postoperative echocardiography, the degree of functional MR was reduced in 34 patients (52%), unchanged in 29 patients (44%), and worsened in 3 patients (5%) compared with preoperative values (Figure 2A). The 3 patients with worsened functional MR had associated substantial reductions in EF without structural abnormality in the MV, indicating the progression of LV remodeling after CABG. The influence of residual functional MR after CABG on clinical outcomes was assessed by comparing the 34 patients with reduced functional MR and the 32 patients with unchanged and worsened functional MR (Table S1).
After a median of 2.9 years (range, 1.6–5.7 years) after CABG, 1 patient with unchanged functional MR died 2 years after the surgery due to cerebral infarction, while there were no deaths in the other patients (P=0.270;
Figure 2B). Major adverse cardiac events, including MI, angina pectoris, repeat intervention, or in-hospital treatment for cardiac failure, occurred in 8 patients without reduced MR and in 5 patients with reduced MR without a statistically significant difference (P=0.351, Kaplan-Meier analysis and log-rank test;
Figure 2C). Notably, 4 patients without reduced MR were treated in hospital for congestive cardiac failure, whereas 1 patient with reduced MR presented with cardiac failure requiring in-hospital treatment (P=0.046,
Figure 2D).
Potential Predictors of Reduced Post-CABG MR
Coronary Artery Pathology
The preoperative angiographic severity of CAD was analyzed as a potential predictive factor of reduced MR after CABG. Three-vessel disease, unprotected left main trunk disease, or unstable state was not associated with changes in MR after CABG (Table S2A). Stenosis grade in the coronary arteries or occlusion of the proximal left anterior descending artery, branch of left circumflex artery, and/or RCA was not associated with the changes in MR after CABG. Moreover, the SYNTAX score or collateral flow associated with total occlusion of the coronary arteries, classified by Rentrop grade, was not associated with changes in MR after CABG.
LV Function and Viability
Global LV function, regional LV wall motion, and myocardial viability and conduction, which were pre- and postoperatively assessed on routine echocardiography and electrocardiography, were analyzed as potential predictive factors for reduced post-CABG MR (Table S2B). Consequently, preoperative EF was not different between the patients with reduced and residual post-CABG MR. Twenty-five patients (38%) had EF <40% preoperatively, while this patient group was not associated with residual MR after CABG. Postoperative increase in EF was not associated with changes in MR (P=0.232,
Figure 3A).
MR reduction differed according to the preoperative hypokinetic region of the LV wall, with a smaller reduction seen in patients with hypokinesia in the inferior/posterior/lateral wall (P=0.063,
Table S3). Moreover, MR reduction was dependent on the viability of the LV wall in patients with inferior/posterior/lateral wall hypokinesia preoperatively (P=0.074,
Table S3). A reduction of LVeDD tended to be associated with reduced MR (P=0.373,
Figure 3B). Complete and incomplete left bundle branch block (LBBB), which were defined as wide QRS (complete LBBB, QRS >0.12 s; incomplete LBBB, 0.10<QRS<0.12 s), monomorphic R waves in I and V6 with no Q waves, and monomorphic S waves in V1 on electrocardiography, were preoperatively diagnosed in 24 patients (36%). Changes in the MR degree after CABG were not different according to preoperative LBBB (P=0.486,
Table S2B).
MV Tethering
Tenting height, Aα, and Pα measured on preoperative off-line transthoracic echocardiography, were analyzed as potential predictive factors of reduced MR degree after CABG. Consequently, tenting height and Aα in the reduced postoperative MR group were significantly greater than in the group without reduced MR (P=0.023 and P<0.001, respectively;
Table S2B), while Pα was not associated with changes in MR (P=0.407;
Table S2B).
Furthermore, the direction of the MR jet, which was classified as anterior, central, or posterior, was analyzed as a potential predictive factor of reduced MR degree after CABG. Consequently, the patients with preoperative anteriorly or centrally directed MR jets were more likely to have reduced MR postoperatively (67%) than those with a posteriorly directed MR jet (22%; P=0.012;
Table S2B;
Figure 4A).
MV Structure
AL, PL, and MAD measured on preoperative off-line transthoracic echocardiography were analyzed as potential predictive factors for reduced MR degree after CABG. Consequently, both AL and PL were significantly longer in patients with reduced MR postoperatively than in those without reduced MR (P=0.049 and P=0.003, respectively,
Table S2B). MAD was not significantly different according to presence of reduced MR postoperatively (P=0.125;
Table S2B).
Additionally, estimated coaptation length was assessed as a factor of the leaflets relative to the annulus. Consequently, preoperative estimated coaptation length was significantly and markedly longer in patients with reduced MR postoperatively (9.3 mm; range, 6.7–11.4 mm) compared with those without reduced MR postoperatively (5.1 mm; range, 2.7–6.3 mm; P=0.001;
Table S2B;
Figure 4B). The cut-off of the estimated coaptation length was 6.5 mm on ROC curve analysis, with an area under the curve (AUC) of 0.863 (Figure 4C). Functional MR was reduced postoperatively in 78% of the patients with estimated coaptation length ≥6.5 mm preoperatively. Conversely, functional MR was reduced postoperatively in 20% of patients with estimated coaptation length <6.5 mm preoperatively (P<0.001,
Figure 4D). Interestingly, the estimated coaptation length was positively correlated with tenting height (r=0.536, P<0.001,
Figure 4E).
New Predictors of Reduced Post-CABG MR
Potential predictive factors, including background, coronary artery pathology, LV function/viability, MV structure/physiology, or surgical approach, were individually assessed on univariate logistic regression analysis to explore factors associated with reduced post-CABG MR. Consequently, 11 factors, consisting of MR severity (mild MR, moderate MR); hypokinetic region of LV wall (inferior/posterior/lateral, general); tenting height; Aα; jet direction (centrally, posteriorly); length of AL; length of PL; and estimated coaptation length; were identified on P<0.10 (Table S2). Factors that correlated with the other factors were removed. Five of 11 factors, including MR severity (moderate MR), hypokinetic region of LV wall (inferior/posterior/lateral), leaflet tethering (Aα), jet direction (posteriorly), and leaflet size (estimated coaptation length) were extracted and further analyzed on multivariate logistic regression to investigate independent predictive factors. Consequently, posteriorly directed MR jet (P=0.016; OR, 0.007; 95% CI: 0.00003–0.2) and estimated coaptation length (P=0.016; OR, 2.2; 95% CI: 1.3–4.8) were independent predictive factors associated with reduced MR degree after CABG (Table 3).
Table 3.
Predictors of Functional MR Reduction
| |
P-value
(univariate) |
P-value
(multivariate) |
OR |
95% CI |
| Moderate MR |
0.016 |
0.064 |
52.3 |
1.5–10,879.3 |
| Inferior/Posterior/Lateral Hypokinesia |
0.045 |
0.420 |
0.4 |
0.05–3.5 |
| Aα (°) |
0.001 |
0.758 |
1.0 |
0.8–1.1 |
| Posteriorly directed MR jet |
0.005 |
0.016 |
0.007 |
0.00003–0.2 |
| eCL (mm) |
0.001 |
0.016 |
2.2 |
1.3–4.8 |
95% CI, 95% confidence interval; eCL, estimated coaptation length; MR, mitral regurgitation; OR, odds ratio.
In previous studies, cardiac function, LV size, and the degree of MV leaflet tethering were associated with MR after CABG.10–12
Here, we explored the impact of the addition of 2 factors (e.g., estimated coaptation length and MR jet direction) to the previously reported factors (EF, LVeDD, and tenting height). The logistic regression model of the 5 factors had better fitting than the 3-factor model (P<0.001). On ROC analysis the AUC of the 5-factor model (0.915) was significantly larger than that of the 3-factor model (0.703, P=0.006;
Figure 5A).
Moreover, we analyzed IDI using probabilities calculated from the 3- and 5-factor models to further verify the statistical significance of the 2 new factors to predict MR reduction after CABG. Consequently, most of the blue points were located above the line y=x, suggesting that the addition of estimated coaptation length and MR jet direction to the previously reported 3 factors increased the predictive precision for MR reduction after CABG. IDI significantly differed between the 2 models (P<0.001;
Figure 5B). Thus, the addition of estimated coaptation length and MR jet direction as predictive factors to the previously reported 3 factors more accurately predicted the outcome of MR after CABG.
Discussion
We reviewed the clinical outcomes associated with functional MR after CABG in patients with mild or moderate functional MR preoperatively, and explored the predictive factors for reduced MR after CABG. Of 66 patients, 48% had unchanged or worsened MR after isolated CABG, which was associated with the emergence of congestive heart failure in the long term. Patient background, coronary artery pathology, global LV function, or surgical approach were not associated with changes in MR degree after CABG. Conversely, estimated coaptation length and posteriorly directed MR jet were predictive factors of changes in MR after CABG. The addition of these 2 new factors to the previously reported predictive factors (EF, eDD, and tenting height) more accurately predicted reduced MR after CABG than the previously reported 3 factors alone.
It has been repeatedly reported that functional MR associated with CAD is the result of structural and/or functional abnormalities of the LV, such as MV annular dilatation, tethering of MV leaflets, or regional ischemia/infarction of the papillary muscle.14,24,25
It has therefore been suggested that recovery of functional MR after CABG depends on the reversibility of the responsible pathology of the LV by revascularization.10,26
Although EF, eDD, and tenting height, which are associated with the viability of the LV myocardium, are predictive factors for the recovery of post-CABG MR, we identified 2 important new factors that can predict changes in degree of MR after CABG: estimated coaptation length and posteriorly directed MR jet.
Estimated coaptation length is a simple index that signifies the size of the MV leaflets relative to the MV annulus on standard transthoracic echocardiography. Importantly, estimated coaptation length was positively correlated with the tenting height of the MV, indicating that leaflet size is positively correlated with tethering severity in the context of mild-moderate MR, and that actual coaptation length was not substantially different despite the different sizes of the leaflet or the severity of tethering. In other words, a combination of severe tethering and poor leaflet tissues results in severe functional MR, whereas a combination of mild tethering and rich leaflet tissues may result in minimal functional MR. It can therefore be asked “what is the pathological association between the size of the leaflets and the leaflet tethering?” This may be explained by the intrinsic nature of the leaflets regardless of LV dilatation-associated leaflet tethering, or by remodeling of the leaflet tissues to adapt to annular dilation, leaflet tethering, and/or emergence of MR, given that mitral leaflet tissues grow in response to chronic mechanical stretching and thus reduce the degree of functional MR.16,27–29
While further studies are needed, it is reasonable to suggest that MV with richer leaflet tissues is less likely to produce MR despite the occurrence of more severe tethering.
In the present study, posteriorly directed MR jet, which suggests predominant tethering of the posterior leaflets, was another important factor to predict residual MR after CABG. This may be explained by the importance of the functionality, viability, and reversibility of the inferior/posterior LV wall to produce the functional MR, as reported by Kumanohoso et al.26
The geometry of the LV and/or the intrinsic location of the papillary muscle may lead to unbalanced tethering of the MV leaflets associated with CAD.
There were several limitations in this retrospective study. Postoperative echocardiography was performed at different time points (1.6–5.7 years), but we selected the first echocardiographic data after one-year interval from CABG and there were no adverse coronary events under the consistent medical treatment during the follow-up period. Cardiac function or degree of MR after CABG does not fluctuate beyond 1 year after surgery, in the absence of adverse coronary events.30
We therefore consider that the difference in the timing of echocardiography would induce minimum change in cardiac function or the degree of MR.
This study was limited by the absence of preoperative myocardial viability data from cardiac magnetic resonance imaging (CMR) and/or stress echocardiography. We assessed the viability of the 4 myocardial areas, however, by comparing the regional wall motion before and after CABG using serial echocardiography. The area that showed improved post-CABG wall motion had myocardial viability, whereas the area without improved wall motion had poor viability. Reduced LV dimension was analyzed with regard to myocardial viability. Although myocardial viability was not analyzed as a predictive factor, myocardial viability was also found to be associated with reduced post-CABG MR degree. Further studies using comprehensive assessment of the viability and/or structure of the LV using the latest imaging tools, such as CMR and/or computed tomography, are warranted.
It could be argued that predicting changes in MR after CABG in the context of mild functional MR is not clinically relevant, given that surgical intervention would not be indicated for mild degrees of functional MR. The degree of functional MR associated with CAD is determined theoretically by the severity of myocardial ischemia, stage of LV remodeling and possible presence of structural abnormality. Although moderate degree of functional MR may differ from a mild degree of functional MR, we consider that the mechanisms of occurrence, progression or recovery of functional MR would not be different between mild and moderate degrees of functional MR. Given that the present patients had a relatively early stage of LV remodeling, we suspect that myocardial ischemia, which would recover after CABG, would be the major determinant of recovery of post-CABG functional MR, whereas non-recovery of MR would indicate the presence of intrinsic structural abnormality, which would not recover after CABG. The moderate functional MR group would be more influenced by the stage of LV remodeling, possibly leading to less exaggeration of the role of structural abnormality in the functional MR, as compared with the mild functional MR group.
In the present study, LV functionality and MV structure appeared to underlie the emergence of functional MR. Although annuloplasty at the time of CABG is the standard surgical method to repair moderate functional MR, annuloplasty that produces unbalanced tethering of the leaflets, such as predominant posterior leaflet tethering, may be associated with failed repair or recurrent MR after surgery.7–9
Conversely, Lee et al suggested that posterior leaflet tethering is unavoidable after annuloplasty, rendering postoperative MV competence highly dependent on distal anterior leaflet mobility.25
Calafiore et al suggested that a tenting height of >10 mm was associated with recurrent MR after repair.31
Further studies are needed to establish the surgical indication and optimal technique for moderate functional MR associated with CAD.
Thus, unchanged or worsened functional MR, even to a mild degree, is associated with the emergence of congestive heart failure in the long-term after CABG. In addition to the reported predictive factors indicating the viability of the LV myocardium, the size of the leaflets relative to the annulus and balance of leaflet tethering are important predictive factors for reversibility of functional MR after CABG.
Disclosures
The authors declare no conflict of interest.
Supplementary Files
Supplementary File 1
Table S1.
Patient background vs. presence of postoperative reduced MR
Table S2.
(A) CAD parameters vs. presence of postoperative reduced MR, (B) LV function and MV structure vs. presence of postoperative reduced MR
Table S3.
Probability of MR reduction vs. region of LV wall preoperative hypokinesis
Please find supplementary file(s);
http://dx.doi.org/10.1253/circj.CJ-16-1280
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