Methods: Between January 2007 and November 2016, a total of 128 patients (72 males, 56 females; mean age 51.8±17.2 years; range 16 to 84 years) who underwent mitral valve repair in our heart center were retrospectively analyzed. There were mitral regurgitation in 86.7% (n=111), mitral stenosis in 7.8% (n=10), and mixed type valve disease in 5.5% of the patients (n=7). Mitral ring annuloplasty was performed in 80.5% (n=103), implantation of the artificial chordae in 36.7% (n=47), open mitral commissurotomy in 13.3% (n=17), and Alfieri procedure in 6.3% (n=8) of the patients. Sixty-two patients (48.8%) underwent isolated mitral valve repair, while concomitant surgical procedures were performed in the remaining patients. Postoperative mean follow-up was 52 months.
Results: Early (30-day) mortality was observed in seven patients due to low cardiac output. There was no mid-term mortality. During follow-up, various degree of mitral regurgitation was detected in 4 patients (3.6%), regurgitation was severe in two of them and these two require reoperation with the replacement of the valve. Patients with a myxomatous valve pathology who underwent isolated valve repair most benefited from valve repair. Patients with isolated mitral stenosis were the most successful group among the patients with a rheumatic etiology. Postoperative echocardiography showed a significant decrease in the left atrial diameter and pulmonary artery systolic pressures (p<0.01).
Conclusion: Mitral valve repair can be applied as an effective and safe treatment method in patients in whom the mitral valve anatomy is sufficient for repair. We suggest that each patient with mitral valve pathology should be evaluated in terms of reparability.
There were mitral regurgitation in 86.7% (n=111), mitral stenosis in 7.8% (n=10), and mixed type valve disease in 5.5% of the patients (n=7). Valve etiology and lesions were identified by the surgeon with the inspection of the valve during the operation. In the regurgitation group, 36% (n=40) were in the Carpentiers functional classification type 1 (ischemic), 47.7% (n=53) were in type 2 (myxomatous and degenerative), 8.1% (n=9) were in type 3a (rheumatic), and 8.1% of the patients (n=9) were in type 3b (ischemic). The etiology was rheumatic (n=6) and congenital (n=1) in the patients with mitral stenosis.
Preoperative transthoracic echocardiography (TTE) was performed in all patients. Furthermore, the patients who were scheduled for repair surgery due to isolated MR received TEE. The assessment of the myocardial viability was performed in 10 patients with an ischemic etiology and low ejection fraction (EF) values.
Preoperative echocardiographic findings of the patients were compared with the postoperative echocardiographic findings with a mean duration of 52.4±36.7 (range, 2 to 136) months. Postoperative early and mid-term complications and mortality rates were observed, and the effectiveness and the recurrence rates of the repair methods in different valve pathologies were investigated. The patients were identified as low- (51.5% [n=66]), intermediate- (32.8% [n=42]), and high-risk group (15.6% [n=20]) according to the EuroSCORE.
Preoperative echocardiographic findings
The EF, left atrium anteroposterior diameter
(LA-diameter), systolic pulmonary artery pressure
(sPAP), presence of left atrial thrombus, type of valve
pathology, grade of MR, and stenosis were determined
by TTE. The presence of annular dilatation,
mitral valve prolapse, prolapsed segments, chordal
elongation, and chordal rupture were examined by
TEE.
Operative technique
All patients were operated by a single surgical
team with median sternotomy under cardiopulmonary
bypass (CPB) with an arrested heart. The mean CPB
and aortic cross-clamp times were 105.2±42.8 min
and 74.5±33.9 min, respectively. All patients were
assessed with TEE prior to repair and after CPB.
Mitral ring annuloplasty (MRA) was performed to
80.5% (n=103), implantation of the artificial chordae to
36.7% (n=47), open mitral commissurotomy to 13.3%
(n=17), and Alfieri procedure to 6.3% of the patients
(n=8). The mean annuloplasty ring size was 31±0.9 mm and the median number of neochordae implanted per
patient was two (range, 2 to 4). Cryoablation was also
performed in all patients (n=22) with preoperative
atrial fibrillation (AF). Techniques used in MV-repair
and concomitant surgical procedures with repair are
shown in Table 2.
Table 1: Patient characteristics
Table 2: Operative techniques and concomitant surgical procedures
Postoperative parameters
Details regarding follow-up of patients were
obtained from subsequent clinic visit and telephone
follow-up. Mortality, myocardial infarction, reoperation for bleeding, inotropic requirement (longer than
24 hours), presence of low cardiac output, duration of
intensive care unit stay (days), and duration of hospital
stay (days) were evaluated in the early postoperative
period (within 30 days). In the mid-term, mortality,
recurrence, reoperation, and thromboembolism were
evaluated. Factors affecting reoperation and survival
were examined. The early and mid-term results of the
patients are given in Table 3.
Table 3: Early and mid-term results
Statistical analysis
Statistical analysis was performed using
the Number Cruncher Statistical System (NCSS)
2007 statistical software (Kaysville, Utah, USA).
Descriptive data were expressed in mean ± standard
deviation (SD), median (min-max) values, frequency,
and percentage. The Mann-Whitney U test was used
to compare the quantitative data and abnormally
distributed data were compared between the groups.
The Kruskal-Wallis test was used to compare three
and more groups without normal distribution. The
Wilcoxon signed-ranks test was used for intra-group
comparison of abnormally distributed variables. The
Kaplan-Meier survival analysis was used for the
survival analysis. A p value of <0.05 was considered
statistically significant.
Postoperative morbidity and mortality
A total of 9.5% of the patients (n=12) were reoperated
for bleeding in the early postoperative period. A total
of 22.2% of the patients (n=28) required inotropic
therapy for longer than 24 hours, and low cardiac
output was observed in 10.3% (n=13) (Table 3). The
mean duration of intensive care unit stay was 2.3±3.2
(range, 1 to 20) days. The mean time to discharge was
11.2±9.6 (range, 5 to 78) days.
The EuroSCORE values of the patients with
mortality were found to be significantly higher
(p=0.001). After MV-repair, seven patients (5.4%) died
due to perioperative congestive heart failure with low
cardiac output in the early period. These patients were
operated for concomitant coronary artery disease and
had high preoperative EuroSCORE values. During
a mean follow-up of 52 months, no mortality was
observed, except for early mortalities. The mean rate
of freedom from death was 94.5±2% at 128 months
postoperatively (Figure 1).
Figure 1: Kaplan-Meier analysis for late survival in the patients
with mitral valve repair.
During the mean postoperative follow-up period of
52.4±36.7 (range, 2 to 136) months, MR was observed
in 31 patients (25.6%) at various grades. Two of them
(1.5%) had severe MR requiring reoperation, and valve
replacement was also performed in these patients.
Freedom from reoperation and recurrent MR were
98.3% and 74.3% at mid-term follow-up, respectively.
Recurrent AF was observed in four patients (18.1%)
who underwent cryoablation.
Postoperative transthoracic echocardiography
Table 4: Preoperative and postoperative transthoracic echocardiographic parameters
Table 5: Evaluation of recurrent mitral regurgitation in patients operated for mitral regurgitation
According to the results of the repair depending on
the etiology, there was no significant difference between
the groups in EF, LA diameter, and sPAP values
(p>0.05). However, a significant difference was found
between the etiological groups in terms of changes in
MR ratios in mid-term follow-up (p=0.001). In the two
group comparisons to identify the group that makes
the difference, the decreases in the MR scores of the
myxomatous group were higher in ischemic (p=0.001)
and rheumatic group (p=0.001). The decreases in the
MR scores of the ischemic group were also higher in the
rheumatic group (p<0.01). The success in repair for MR
follows from high-to-low for myxomatous, ischemic,
and rheumatic groups, respectively (Table 7).
Table 7: Evaluation of mid-term results according to etiologic groups
There was no significant difference between
preoperative and postoperative EF (p>0.05). The LA
diameter showed improvement by a mean reduction
of 2.2±7.3 mm (p=0.001). Postoperative sPAP values
decreased by a mean of 5.0±14.2 mmHg (p=0.001)
(Table 4). Significant (moderate-to-severe) MR was
observed in four patients with pure MR after MV-repair
in mid-term (Table 5). There was no significant MR
detected in the patients with mitral stenosis and mixed
type valve lesions (Table 6).
In our series, the survival rate was 94.6% at the mean follow-up of 52 months. All mortalities were observed in patients who underwent combined coronary artery bypass grafting (CABG) with MV-repair due to low cardiac output in the early postoperative period. Reoperation requirement was reported to be in only one of 103 patients who underwent MV-repair in the study evaluating the results of MV-repair by Korkmaz et al.[5] In our series, reoperation requirement was two of 128 patients (1.5%). During follow-up, the patients who needed valve replacement were excluded from the study.
In the present study, we determined which surgical technique should be used for pathology using preoperative TEE in all the patients for whom we planned valve repair. Preoperative TEE was not performed in the patients who underwent operation with other surgical indications (i.e., coronary artery disease, other valve diseases, congenital heart diseases). Perioperative TEE was used to assess the mitral valve functions after valve repair.
Ring annuloplasty is a common and reliable method to preserve the shape and diameter of the mitral valve after repair. We used flexible annuloplasty ring with valve repair in all patients with MR. Borghetti et al.[6] r eported t hat f lexible r ings w ere s uperior t o rigid rings in preservation of LV function and valve physiology. Flexible rings were superior in terms of the preservation of EF and mitral valve area; however, there was no significant difference in recurrence, reoperation, and mortality rates between the rings in the study comparing flexibles and rigid rings.[4] In our study, gradient up to 5 mmHg and regurgitation up to Grade 2 on mitral valve were considered negligible after repair. Valve replacement was performed in two patients due to the development of severe MR in midterm follow-up.
Gillinov et al.[7] reported that quadrangular resection and annuloplasty applied for prolapse of the posterior valve are associated with lower reoperation rates. Implantation of artificial chordae has become the preferred option, rather than quadrangular resection, in valve repair surgery owing to several advantages, including simplicity and preservation of valve tissue.[8] We currently p erform the implantation of artificial chordae (n=47), rather than the quadrangular resection (n=9) which we used more frequently in our initial cases.
In developed countries, the most frequent etiological cause in patients undergoing repair is degenerative mitral valve disease.[9] Rheumatic valve diseases are still the most common etiological factors in Turkey. In our series, 17.9% (n=23) of the patients who underwent valve repair surgery had rheumatic valve disease.
In their study, Fedakar et al.[10] reported that MV-repair can be safely performed in patients with combined mitral stenosis and regurgitation and rheumatic mitral valve disease. Combined mitral stenosis and regurgitation was present in 5.5% (n=7) of the patients in our series. In mid-term follow-up, neither severe MR nor stenosis requiring valve replacement after repair was detected. Pathology requiring reoperation was not detected in the mid-term follow-up of the 10 patients (7.8%) who underwent repair for pure rheumatic mitral stenosis. Nevertheless, repair strategies in rheumatic mitral valve disease are still one of the most controversial issues. Also, MV-repair is more complex and less durable in these patients.[11] Fibrosis, thickening, and calcification of the valvular and subvalvular apparatus are the main problems which make repair technically difficult.
The etiology was ischemic MR in 38.3% of the patients (n=49), and CABG was performed combined with valve repair. Operative mortality and morbidity are higher in ischemic MR, and survival rates are lower than other etiologies (rheumatic or degenerative).[12,13] The mitral valve is often normal in these patients. Restrictive movement of mitral valve leaflets is present due to the displacement of the papillary muscle (Carpentier type 3b) and displacement of the chordal attachment points of the mitral valve (Carpentier type 1). Posterior annular dilatation secondary to the left ventricular dilation is also observed.[12,14]
The main goals of combined CABG and mitral reduction annuloplasty are to reduce the mitral annular size in the anterior-posterior direction, to increase the degree of valve coaptation, and to prevent further aneurysm dilatation.[13] The removal of myocardial and, hence, papillary muscle ischemia would be reflected positively on left ventricular geometry and would improve mitral valve function. However, in the case of valve repair in ischemic MR, which is accepted as functional regurgitation, the results of postoperative valve regurgitation and necessity of reoperation are not as satisfactory as in degenerative and myxomatous valve repair.[15] Today, the gold standard treatment of functional MR is combined undersized MRA and CABG. Nevertheless, this procedure results in a recurrence rate of 20 to 30% after two to four years.[16,17]
Recent studies have demonstrated the results in favor of the ring annuloplasty in terms of early survival compared to valve replacement; however, no differences were observed between mid-term results in ischemic MR.[18] On the other hand, there is a controversy on whether ring annuloplasty is superior to valve replacement.
The failure of MV-repair usually occurs due to insufficient or excessive valve leaflet excision, recurrence of chordal rupture, mitral stenosis, or systolic anterior motion.[19] In our series, moderateto- severe MR was detected in perioperative TEE in four patients, and valve replacement was performed in these cases. In mid-term follow-up, MVR was postoperatively performed in two patients at 22 months and at 37 months, respectively. These patients were those who underwent combined undersized MRA and CABG due to annular dilatation. We attributed the cause of reoperation in these patients to deteriorated left ventricular geometry.
Furthermore, in a series of mitral valve repair
reported by Onan et al.,[
Similar survival rates can be achieved in
asymptomatic patients with preserved left ventricular
function as in the normal population in the MV-repair
surgery.[22,23] Besides, MV-repair provides an
improvement in the contractile function, postoperative
quality of life, and mid-term survival, particularly in
patients with impaired left ventricular function. It is
considered an important advantage that anticoagulation
is not required in the mid-term after valve repair in
terms of complications associated with anticoagulants.
In-hospital complications were at the expected rates in
our series. In our mid-term results, recurrences were
not observed, except for two patients.
In conclusion, the valve repair surgery should be
considered an effective and safe treatment method in
all patients with a sufficient valve anatomy for repair.
We advocate that reparability should be evaluated
and valve replacement should be avoided, whenever
possible, in mitral valve surgery. Successful results
with increasing experience of institutions in mitral
valve repair would also change indications for surgical
treatment.
Declaration of conflicting interests
Funding
The authors declared no conflicts of interest with respect to
the authorship and/or publication of this article.
The authors received no financial support for the research
and/or authorship of this article.
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