Accepted Manuscript Left Ventricular Performance Early after Repair for Posterior Mitral Leaflet Prolapse: Chordal Replacement versus Leaflet Resection Ken-ichi Imasaka, MD, PhD, Eiki Tayama, MD, PhD, Yukihiro Tomita, MD, PhD PII:
S0022-5223(15)01030-2
DOI:
10.1016/j.jtcvs.2015.06.022
Reference:
YMTC 9645
To appear in:
The Journal of Thoracic and Cardiovascular Surgery
Received Date: 3 March 2015 Revised Date:
19 May 2015
Accepted Date: 6 June 2015
Please cite this article as: Imasaka K-i, Tayama E, Tomita Y, Left Ventricular Performance Early after Repair for Posterior Mitral Leaflet Prolapse: Chordal Replacement versus Leaflet Resection, The Journal of Thoracic and Cardiovascular Surgery (2015), doi: 10.1016/j.jtcvs.2015.06.022. This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
1
ACCEPTED MANUSCRIPT
1
Left Ventricular Performance Early after Repair for Posterior Mitral Leaflet Prolapse:
2
Chordal Replacement versus Leaflet Resection
3
5
Ken-ichi Imasaka, MD, PhD
6
Eiki Tayama, MD, PhD
7
Yukihiro Tomita, MD, PhD
10
The Department of Cardiovascular Surgery, Clinical Research Institute, National Hospital
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SC
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Organization Kyushu Medical Center, Fukuoka, Japan
11 12
Correspondence to Yukihiro Tomita, MD, PhD
14
Department of Cardiovascular Surgery
15
National Hospital Organization Kyushu Medical Center
16
1-8-1 Jigyo-hama, Chuo-ku, Fukuoka 812-8582, Japan
17
Fax: +81-92-847-8802; Tel: +81-92-852-0700
18
E-mail: [email protected]
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Total word count: 4702 words
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Conflict of interest: none
23
Funding for this work: none
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ACCEPTED MANUSCRIPT
Abstract (248 words)
2
Objectives: We aimed to review hemodynamic performance early after valve repair with
3
chordal replacement versus leaflet resection for posterior mitral leaflet prolapse.
4
Methods: Between April 2006 and September 2014, 72 consecutive patients underwent valve
5
repair with chordal replacement (30 patients) or leaflet resection (42 patients) for isolated
6
posterior mitral leaflet prolapse. Left ventricular ejection fraction, end-systolic elastance,
7
effective arterial elastance, and ventricular efficiency were non-invasively measured by
8
echocardiography and analyzed preoperatively and ~1 month postoperatively. Mitral valve
9
repair was accomplished in all patients, and no regurgitation (including trivial) was observed
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postoperatively.
11
Results: Chordal replacement resulted in significantly less reduction in left ventricular ejection
12
fraction, and significantly greater increase in end-systolic elastance than leaflet resection (left
13
ventricular ejection fraction: 4.8% versus 16.7% relative decrease, P = 0.005; end-systolic
14
elastance: 19.0% versus -1.3% relative increase, P = 0.012). Despite comparable preoperative
15
ventricular efficiency between the groups, the postoperative ventricular efficiency in the chordal
16
replacement group was superior to that in the leaflet resection group (ventriculoarterial
17
coupling: 32.0% versus 89.3% relative increase, P = 0.007; ratio of stroke work to
18
pressure-volume area: 4.3% versus 13.4% relative decrease, P = 0.008). In multivariate analysis,
19
operative technique was a significant determinant of left ventricular ejection fraction and ratio
20
of stroke work to pressure-volume area (P = 0.030 and P = 0.030, respectively).
21
Conclusions: Chordal replacement might provide patients undergoing valve repair for posterior
22
mitral leaflet prolapse with better postoperative ventricular performance than leaflet resection. A
23
longer follow-up is required to compare long-term outcomes.
24
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Central Message (18 words)
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Our findings suggested that LV performance in patients undergoing chordal replacement was
3
superior to that in leaflet resection.
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Perspective (58 words)
2
Little is known regarding the relative superiority of chordal replacement or leaflet resection as
3
operative techniques for valve repair in PML prolapse. Our findings suggested that LV
4
performance after chordal replacement was superior to that after leaflet resection. This result
5
contributes to clarifying the optimal technique to preserve LV function in patients undergoing
6
MV repair for PML prolapse.
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Ultramini-abstract (46 words)
2
We performed a comparative study of postoperative LV performance in patients who
3
undergoing mitral valve repair using chordal replacement or leaflet resection for isolated
4
posterior mitral leaflet prolapse. Our findings showed that LV performance in chordal
5
replacement group was superior to that in leaflet resection group.
6
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Key words: left ventricular performance, mitral valve repair, chordal replacement, leaflet
8
resection
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Introduction
2
Mitral valve (MV) repair is now the standard treatment of choice for the majority of patients
3
with degenerative mitral regurgitation (MR). In general, prolapse of the posterior mitral leaflet
4
(PML) is more common than prolapse of the anterior mitral leaflet or both mitral leaflets. A
5
broad spectrum of reconstructive techniques has been developed to treat the complex MV
6
pathology.1-4 Of these techniques, quadrangular resection of the prolapsing segment with or
7
without sliding plasty has been the standard technique for the repair of PML.1 Limited triangular
8
resection of PML has also been reported as a good alternative procedure that significantly
9
reduces resection size and eliminates annular compression.2 In addition to these leaflet resection
10
procedures, MV repair by chordal replacement with expanded polytetrafluoroethylene (e-PTFE)
11
sutures is a technique that shows high effectiveness and reliability in patients with PML
12
prolapse.3,4 Furthermore, we previously reported this technique could also be applied to anterior
13
or bilateral mitral leaflet prolapse, as well as uncommon MV prolapse.5-8 However, the effect of
14
the respective reconstructive techniques on left ventricular (LV) function remains unclear.
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Parameters such as LV cavity dimensions and ejection fraction (EF) have been widely
16
used in a number of studies to detect subclinical LV myocardial dysfunction for chronic
17
degenerative MR. However, LV dysfunction as assessed by echocardiography is often
18
underestimated in patients with severe MR because of a systolic unloading effect resulting from
19
low-resistance ejection to the left atrium.9,10 Therefore, EF might not be a precise index of LV
20
systolic contractility in patients with MR.
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End-systolic elastance (Ees), effective arterial elastance (Ea), ventriculoarterial
22
coupling (Ea/Ees), and the stroke work to pressure-volume area (SW/PVA) ratio enable analysis
23
of LV contractility, afterload, and ventricular efficiency.11,12 Previously, LV performance was
24
analyzed in patients undergoing MV surgery (asymptomatic patients vs. symptomatic patients,
25
or MV repair vs. MV replacement).13,14 In the present study, we hypothesized that the choice of
26
operative technique (chordal replacement or leaflet resection) could impact postoperative LV
7
ACCEPTED MANUSCRIPT
function in patients undergoing MV repair for PML prolapse. Therefore, we sought to 1) assess
2
postoperative LV function including LV mechanics in patients undergoing MV repair with
3
chordal replacement in comparison to patients with leaflet resection, and 2) investigate
4
determinants of postoperative LV function in multivariate analysis.
5 6
Methods
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Study Population
9
This study was approved by the Institutional Review Board, and the medical records of patients
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10
undergoing MV repair for chronic severe MR were reviewed retrospectively. The Institutional
11
Review Board waived the requirement for obtaining individual consent.
12
From April 2006 to September 2014, isolated MV repair for PML prolapse was performed in 72 patients with chronic severe MR. We included patients undergoing concomitant
14
tricuspid annuloplasty (TAP) (n = 24) or the Maze procedure (n = 14). One patient underwent
15
MV repair with quadrangular resection for recurrence of PML prolapse 10 years after MV repair
16
with chordal replacement. The MR was assessed by transesophageal or transthoracic
17
echocardiography before and ~1 month after the surgery. It was graded according to the
18
published guidelines using an integrated approach that included valvular morphological
19
characteristics, regurgitant jet size in the left atrium, proximal regurgitant jet width, and
20
pulmonary venous flow pattern.15 No patients underwent MV replacement following
21
unsuccessful repair.
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Surgical Procedure
24
The MV repair was performed under cardiopulmonary bypass, with aortic and bicaval
25
cannulation and tepid hypothermia. Myocardial protection was achieved using antegrade and
26
retrograde cardioplegia. The MV was exposed through a superior transseptal approach (n = 29)
8
ACCEPTED MANUSCRIPT
or in left atriotomy through the interatrial groove (n = 43). The standard technique for MV
2
repair was performed according to the anatomic lesions responsible for MR. MV repair for the
3
PML prolapse was performed using artificial chordal replacement with e-PTFE (n = 30),
4
quadrangular resection (n = 30), and triangular resection (n = 12).
5
RI PT
1
In the chordal replacement technique, briefly, the double-armed sutures (CV-4 e-PTFE sutures) are passed twice through the fibrous portion of the papillary muscle head that anchors
7
the elongated or ruptured chordae. The two arms of the suture are then brought up to the free
8
margin of the leaflet and passed through the point where the original chordae were attached
9
(thickened portion of the leaflet). The needle is brought from the ventricular side of the leaflet to
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its atrial side and then passed once more through the leaflet. The length of the e-PTFE chordae
11
is adjusted by referring to the contact area of the opposite leaflet. Once the length is adjusted,
12
both ends of the suture are passed through the leaflet again and tied together on the ventricular
13
side. We did not use any pledgets. When the prolapsed portion was wide, another PTFE suture
14
was placed in the same manner.5-8
15
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Meanwhile, the leaflet resection was performed using standard techniques of resection in the redundant posterior leaflet tissue.1,2 After the resection of PML prolapse, the
17
approximation of the leaflet remnants was followed by using interrupted sutures. The MV repair
18
was completed by a sliding annuloplasty or annular plication whenever necessary. No
19
concomitant procedure to chordal replacement or leaflet resection was performed in any of the
20
patients. Ring annuloplasty (Cosgrove ring, n = 20; Edwards Lifesciences, Irvine, CA; Physio
21
ring, n = 52; Edwards Lifesciences, Irvine, CA) was performed in all cases. The ring size for
22
annuloplasty was chosen according to the area of the anterior leaflet. The choices of the
23
annuloplasty ring and repair technique were determined according to surgeon preference.
24
Twenty four patients with functional tricuspid regurgitation underwent ring TAP
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(Edwards Lifesciences, Irvine, CA) (9 patients) or suture TAP (Kay’s procedure) (15 patients)
26
with concomitant MV repair.
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1
For evaluating residual MR, cold cardioplegic solution and saline solution were injected into the LV cavity. The repair was considered acceptable when the regurgitation was
3
less than trivial during testing. After removal of the cardiopulmonary bypass, the presence of
4
residual MR was reevaluated in all cases by intraoperative transesophageal echocardiography.
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5 Echocardiographic Data
7
The MR severity and LV function were assessed by transthoracic or transesophageal
8
echocardiography before and ~1 month after MV repair. LV volume was calculated by the
9
Teichholz M-mode method using echocardiography data, LV end-diastolic dimension, and end-systolic dimension.16 Moreover, the EF (%) was calculated as follows:
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EF = (1– LV end-systolic volume/LV end-diastolic volume) × 100
13 LV mechanics
15
Arterial blood pressure (BP) was measured by the Korotkoff technique using the manchette
16
method. Systolic and diastolic pressure values corresponded to the onset of phase I and V
17
Korotkoff sounds, respectively. Diastolic Korotkoff phase IV was used when the sounds were
18
audible even after complete deflation of the manchette cuff.17 The mean arterial pressure was
19
calculated as follows:
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Mean arterial pressure = (systolic BP – diastolic BP)/3 + diastolic BP
23
The calculation of Ees (contractility) and Ea (afterload) were performed by an approximation
24
method as previously described.13,14,18 The approximation of Ees and Ea were as follows:
25 26
Ees = mean arterial pressure/minimal LV volume
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1 2
Ea = maximal LV pressure/(maximal LV volume – minimal LV volume)
3 Maximal LV pressure and volume were defined as being the same as the systolic BP and LV
5
end-diastolic volume, respectively. The minimal LV volume was defined as being the same as
6
the LV end-systolic volume. The LV volume was normalized to body surface area. Ea/Ees12 and
7
SW/PVA were calculated as indexes of LV efficiency. The SW/PVA (%) was calculated as
8
follows:19
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SW/PVA = 1/(1 + 0.5 Ea/Ees) × 100
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LV Mass Index (LVMI)
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The LV mass was calculated in grams as follows:20
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LV mass = 0.80 × (1.04 × [LV end-diastolic dimension + posterior wall thickness in diastole +
16
septal wall thickness in diastole]3 – [LV end-diastolic dimension]3) + 0.6
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The results obtained were indexed to the body surface area and expressed as g/m2.
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Moreover, to distinguish the effect of LV function in MV surgery using chordal replacement
21
from that using leaflet resection, the changes in postoperative parameters (LVEF, LVMI, Ees,
22
Ea, Ea/Ees, and SW/PVA) were calculated as follows:
23 24
Relative change (%) = (postoperative parameter – preoperative parameter)/preoperative
25
parameter × 100
26
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Statistical Analysis
2
Categorical variables were expressed as frequencies and percentages, and continuous variables
3
as means ± standard deviations. On the other hand, the changes in postoperative parameters
4
(LVMI, LVEF, Ees, Ea, Ea/Ees, and SW/PVA) were expressed as means ± standard error. The
5
Mann-Whitney U test (unpaired data) and Wilcoxon Rank test (paired samples) were used to
6
compare continuous variables, while Fisher’s exact test was used to compare categorical
7
variables. The sample size of 72 patients undergoing MV repair (fixing α = 0.05, 1-β = 0.8, and
8
effect size = 0.7) was sufficient for statistical comparisons of unpaired and paired two-sample.
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We performed univariate regression analysis with LVMI, LVEF, Ees, Ea, Ea/Ees, and
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SW/PVA as independent variables. Then, multivariate analysis based on stepwise multiple
11
linear regression was performed among variables with significant univariate correlations. A P
12
value < 0.05 was considered statistically significant. The data were analyzed using the statistical
13
analysis system software JMP 11.0.0 (SAS Institute Inc, Cary, NC).
15
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Results
Patients’ Characteristics and Surgical Data
17
Table 1 shows the patients’ characteristics and surgical data. Of the study population, there were
18
47 men and 25 women; the mean age was 62.9 ± 12.9 years (range, 33–87 years). The
19
preoperative electrocardiogram revealed atrial fibrillation in 16 patients. Fifty-nine patients
20
were designated as New York Heart Association functional class I or II, and 13 were designated
21
as class III or IV. In terms of preoperative characteristics, no differences were observed between
22
the chordal replacement and leaflet resection groups. With respect to surgical data, the superior
23
transseptal approach and TAP were performed more frequently in the chordal replacement group
24
than in the leaflet resection group (each parameter P < 0.001). Meanwhile, the Cosgrove ring
25
was used more frequently in MV repair with leaflet resection than in that with chordal
26
replacement (P < 0.001). The mean annuloplasty ring size was observed to be 28.4±1.4 mm for
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both groups (P = 0.975). Although the aortic cross-clamping time was comparable between both
2
groups (P = 0.096), the cardiopulmonary bypass time was significantly longer in the chordal
3
replacement group than that in the leaflet resection group (P = 0.011). No perioperative or
4
hospital deaths were recorded.
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5 Hemodynamic Data
7
The preoperative and postoperative hemodynamic data for MV repair with chordal replacement
8
or leaflet resection are shown in Table 2. The LVMI significantly decreased early after surgery
9
for both the chordal replacement and leaflet resection group (each P
S0022-5223(15)01030-2
DOI:
10.1016/j.jtcvs.2015.06.022
Reference:
YMTC 9645
To appear in:
The Journal of Thoracic and Cardiovascular Surgery
Received Date: 3 March 2015 Revised Date:
19 May 2015
Accepted Date: 6 June 2015
Please cite this article as: Imasaka K-i, Tayama E, Tomita Y, Left Ventricular Performance Early after Repair for Posterior Mitral Leaflet Prolapse: Chordal Replacement versus Leaflet Resection, The Journal of Thoracic and Cardiovascular Surgery (2015), doi: 10.1016/j.jtcvs.2015.06.022. This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
1
ACCEPTED MANUSCRIPT
1
Left Ventricular Performance Early after Repair for Posterior Mitral Leaflet Prolapse:
2
Chordal Replacement versus Leaflet Resection
3
5
Ken-ichi Imasaka, MD, PhD
6
Eiki Tayama, MD, PhD
7
Yukihiro Tomita, MD, PhD
10
The Department of Cardiovascular Surgery, Clinical Research Institute, National Hospital
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SC
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Organization Kyushu Medical Center, Fukuoka, Japan
11 12
Correspondence to Yukihiro Tomita, MD, PhD
14
Department of Cardiovascular Surgery
15
National Hospital Organization Kyushu Medical Center
16
1-8-1 Jigyo-hama, Chuo-ku, Fukuoka 812-8582, Japan
17
Fax: +81-92-847-8802; Tel: +81-92-852-0700
18
E-mail: [email protected]
21
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Total word count: 4702 words
22
Conflict of interest: none
23
Funding for this work: none
24
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2
ACCEPTED MANUSCRIPT
Abstract (248 words)
2
Objectives: We aimed to review hemodynamic performance early after valve repair with
3
chordal replacement versus leaflet resection for posterior mitral leaflet prolapse.
4
Methods: Between April 2006 and September 2014, 72 consecutive patients underwent valve
5
repair with chordal replacement (30 patients) or leaflet resection (42 patients) for isolated
6
posterior mitral leaflet prolapse. Left ventricular ejection fraction, end-systolic elastance,
7
effective arterial elastance, and ventricular efficiency were non-invasively measured by
8
echocardiography and analyzed preoperatively and ~1 month postoperatively. Mitral valve
9
repair was accomplished in all patients, and no regurgitation (including trivial) was observed
M AN U
SC
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1
postoperatively.
11
Results: Chordal replacement resulted in significantly less reduction in left ventricular ejection
12
fraction, and significantly greater increase in end-systolic elastance than leaflet resection (left
13
ventricular ejection fraction: 4.8% versus 16.7% relative decrease, P = 0.005; end-systolic
14
elastance: 19.0% versus -1.3% relative increase, P = 0.012). Despite comparable preoperative
15
ventricular efficiency between the groups, the postoperative ventricular efficiency in the chordal
16
replacement group was superior to that in the leaflet resection group (ventriculoarterial
17
coupling: 32.0% versus 89.3% relative increase, P = 0.007; ratio of stroke work to
18
pressure-volume area: 4.3% versus 13.4% relative decrease, P = 0.008). In multivariate analysis,
19
operative technique was a significant determinant of left ventricular ejection fraction and ratio
20
of stroke work to pressure-volume area (P = 0.030 and P = 0.030, respectively).
21
Conclusions: Chordal replacement might provide patients undergoing valve repair for posterior
22
mitral leaflet prolapse with better postoperative ventricular performance than leaflet resection. A
23
longer follow-up is required to compare long-term outcomes.
24
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Central Message (18 words)
2
Our findings suggested that LV performance in patients undergoing chordal replacement was
3
superior to that in leaflet resection.
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Perspective (58 words)
2
Little is known regarding the relative superiority of chordal replacement or leaflet resection as
3
operative techniques for valve repair in PML prolapse. Our findings suggested that LV
4
performance after chordal replacement was superior to that after leaflet resection. This result
5
contributes to clarifying the optimal technique to preserve LV function in patients undergoing
6
MV repair for PML prolapse.
RI PT
1
AC C
EP
TE D
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Ultramini-abstract (46 words)
2
We performed a comparative study of postoperative LV performance in patients who
3
undergoing mitral valve repair using chordal replacement or leaflet resection for isolated
4
posterior mitral leaflet prolapse. Our findings showed that LV performance in chordal
5
replacement group was superior to that in leaflet resection group.
6
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1
Key words: left ventricular performance, mitral valve repair, chordal replacement, leaflet
8
resection
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Introduction
2
Mitral valve (MV) repair is now the standard treatment of choice for the majority of patients
3
with degenerative mitral regurgitation (MR). In general, prolapse of the posterior mitral leaflet
4
(PML) is more common than prolapse of the anterior mitral leaflet or both mitral leaflets. A
5
broad spectrum of reconstructive techniques has been developed to treat the complex MV
6
pathology.1-4 Of these techniques, quadrangular resection of the prolapsing segment with or
7
without sliding plasty has been the standard technique for the repair of PML.1 Limited triangular
8
resection of PML has also been reported as a good alternative procedure that significantly
9
reduces resection size and eliminates annular compression.2 In addition to these leaflet resection
10
procedures, MV repair by chordal replacement with expanded polytetrafluoroethylene (e-PTFE)
11
sutures is a technique that shows high effectiveness and reliability in patients with PML
12
prolapse.3,4 Furthermore, we previously reported this technique could also be applied to anterior
13
or bilateral mitral leaflet prolapse, as well as uncommon MV prolapse.5-8 However, the effect of
14
the respective reconstructive techniques on left ventricular (LV) function remains unclear.
TE D
M AN U
SC
RI PT
1
Parameters such as LV cavity dimensions and ejection fraction (EF) have been widely
16
used in a number of studies to detect subclinical LV myocardial dysfunction for chronic
17
degenerative MR. However, LV dysfunction as assessed by echocardiography is often
18
underestimated in patients with severe MR because of a systolic unloading effect resulting from
19
low-resistance ejection to the left atrium.9,10 Therefore, EF might not be a precise index of LV
20
systolic contractility in patients with MR.
AC C
21
EP
15
End-systolic elastance (Ees), effective arterial elastance (Ea), ventriculoarterial
22
coupling (Ea/Ees), and the stroke work to pressure-volume area (SW/PVA) ratio enable analysis
23
of LV contractility, afterload, and ventricular efficiency.11,12 Previously, LV performance was
24
analyzed in patients undergoing MV surgery (asymptomatic patients vs. symptomatic patients,
25
or MV repair vs. MV replacement).13,14 In the present study, we hypothesized that the choice of
26
operative technique (chordal replacement or leaflet resection) could impact postoperative LV
7
ACCEPTED MANUSCRIPT
function in patients undergoing MV repair for PML prolapse. Therefore, we sought to 1) assess
2
postoperative LV function including LV mechanics in patients undergoing MV repair with
3
chordal replacement in comparison to patients with leaflet resection, and 2) investigate
4
determinants of postoperative LV function in multivariate analysis.
5 6
Methods
7
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1
Study Population
9
This study was approved by the Institutional Review Board, and the medical records of patients
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SC
8
10
undergoing MV repair for chronic severe MR were reviewed retrospectively. The Institutional
11
Review Board waived the requirement for obtaining individual consent.
12
From April 2006 to September 2014, isolated MV repair for PML prolapse was performed in 72 patients with chronic severe MR. We included patients undergoing concomitant
14
tricuspid annuloplasty (TAP) (n = 24) or the Maze procedure (n = 14). One patient underwent
15
MV repair with quadrangular resection for recurrence of PML prolapse 10 years after MV repair
16
with chordal replacement. The MR was assessed by transesophageal or transthoracic
17
echocardiography before and ~1 month after the surgery. It was graded according to the
18
published guidelines using an integrated approach that included valvular morphological
19
characteristics, regurgitant jet size in the left atrium, proximal regurgitant jet width, and
20
pulmonary venous flow pattern.15 No patients underwent MV replacement following
21
unsuccessful repair.
EP
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22
TE D
13
23
Surgical Procedure
24
The MV repair was performed under cardiopulmonary bypass, with aortic and bicaval
25
cannulation and tepid hypothermia. Myocardial protection was achieved using antegrade and
26
retrograde cardioplegia. The MV was exposed through a superior transseptal approach (n = 29)
8
ACCEPTED MANUSCRIPT
or in left atriotomy through the interatrial groove (n = 43). The standard technique for MV
2
repair was performed according to the anatomic lesions responsible for MR. MV repair for the
3
PML prolapse was performed using artificial chordal replacement with e-PTFE (n = 30),
4
quadrangular resection (n = 30), and triangular resection (n = 12).
5
RI PT
1
In the chordal replacement technique, briefly, the double-armed sutures (CV-4 e-PTFE sutures) are passed twice through the fibrous portion of the papillary muscle head that anchors
7
the elongated or ruptured chordae. The two arms of the suture are then brought up to the free
8
margin of the leaflet and passed through the point where the original chordae were attached
9
(thickened portion of the leaflet). The needle is brought from the ventricular side of the leaflet to
M AN U
SC
6
its atrial side and then passed once more through the leaflet. The length of the e-PTFE chordae
11
is adjusted by referring to the contact area of the opposite leaflet. Once the length is adjusted,
12
both ends of the suture are passed through the leaflet again and tied together on the ventricular
13
side. We did not use any pledgets. When the prolapsed portion was wide, another PTFE suture
14
was placed in the same manner.5-8
15
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10
Meanwhile, the leaflet resection was performed using standard techniques of resection in the redundant posterior leaflet tissue.1,2 After the resection of PML prolapse, the
17
approximation of the leaflet remnants was followed by using interrupted sutures. The MV repair
18
was completed by a sliding annuloplasty or annular plication whenever necessary. No
19
concomitant procedure to chordal replacement or leaflet resection was performed in any of the
20
patients. Ring annuloplasty (Cosgrove ring, n = 20; Edwards Lifesciences, Irvine, CA; Physio
21
ring, n = 52; Edwards Lifesciences, Irvine, CA) was performed in all cases. The ring size for
22
annuloplasty was chosen according to the area of the anterior leaflet. The choices of the
23
annuloplasty ring and repair technique were determined according to surgeon preference.
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Twenty four patients with functional tricuspid regurgitation underwent ring TAP
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(Edwards Lifesciences, Irvine, CA) (9 patients) or suture TAP (Kay’s procedure) (15 patients)
26
with concomitant MV repair.
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For evaluating residual MR, cold cardioplegic solution and saline solution were injected into the LV cavity. The repair was considered acceptable when the regurgitation was
3
less than trivial during testing. After removal of the cardiopulmonary bypass, the presence of
4
residual MR was reevaluated in all cases by intraoperative transesophageal echocardiography.
RI PT
2
5 Echocardiographic Data
7
The MR severity and LV function were assessed by transthoracic or transesophageal
8
echocardiography before and ~1 month after MV repair. LV volume was calculated by the
9
Teichholz M-mode method using echocardiography data, LV end-diastolic dimension, and end-systolic dimension.16 Moreover, the EF (%) was calculated as follows:
M AN U
10
SC
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11 12
EF = (1– LV end-systolic volume/LV end-diastolic volume) × 100
13 LV mechanics
15
Arterial blood pressure (BP) was measured by the Korotkoff technique using the manchette
16
method. Systolic and diastolic pressure values corresponded to the onset of phase I and V
17
Korotkoff sounds, respectively. Diastolic Korotkoff phase IV was used when the sounds were
18
audible even after complete deflation of the manchette cuff.17 The mean arterial pressure was
19
calculated as follows:
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Mean arterial pressure = (systolic BP – diastolic BP)/3 + diastolic BP
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The calculation of Ees (contractility) and Ea (afterload) were performed by an approximation
24
method as previously described.13,14,18 The approximation of Ees and Ea were as follows:
25 26
Ees = mean arterial pressure/minimal LV volume
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Ea = maximal LV pressure/(maximal LV volume – minimal LV volume)
3 Maximal LV pressure and volume were defined as being the same as the systolic BP and LV
5
end-diastolic volume, respectively. The minimal LV volume was defined as being the same as
6
the LV end-systolic volume. The LV volume was normalized to body surface area. Ea/Ees12 and
7
SW/PVA were calculated as indexes of LV efficiency. The SW/PVA (%) was calculated as
8
follows:19
SC
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10
SW/PVA = 1/(1 + 0.5 Ea/Ees) × 100
11
M AN U
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12
LV Mass Index (LVMI)
13
The LV mass was calculated in grams as follows:20
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LV mass = 0.80 × (1.04 × [LV end-diastolic dimension + posterior wall thickness in diastole +
16
septal wall thickness in diastole]3 – [LV end-diastolic dimension]3) + 0.6
18
EP
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The results obtained were indexed to the body surface area and expressed as g/m2.
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Moreover, to distinguish the effect of LV function in MV surgery using chordal replacement
21
from that using leaflet resection, the changes in postoperative parameters (LVEF, LVMI, Ees,
22
Ea, Ea/Ees, and SW/PVA) were calculated as follows:
23 24
Relative change (%) = (postoperative parameter – preoperative parameter)/preoperative
25
parameter × 100
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Statistical Analysis
2
Categorical variables were expressed as frequencies and percentages, and continuous variables
3
as means ± standard deviations. On the other hand, the changes in postoperative parameters
4
(LVMI, LVEF, Ees, Ea, Ea/Ees, and SW/PVA) were expressed as means ± standard error. The
5
Mann-Whitney U test (unpaired data) and Wilcoxon Rank test (paired samples) were used to
6
compare continuous variables, while Fisher’s exact test was used to compare categorical
7
variables. The sample size of 72 patients undergoing MV repair (fixing α = 0.05, 1-β = 0.8, and
8
effect size = 0.7) was sufficient for statistical comparisons of unpaired and paired two-sample.
SC
We performed univariate regression analysis with LVMI, LVEF, Ees, Ea, Ea/Ees, and
M AN U
9
RI PT
1
10
SW/PVA as independent variables. Then, multivariate analysis based on stepwise multiple
11
linear regression was performed among variables with significant univariate correlations. A P
12
value < 0.05 was considered statistically significant. The data were analyzed using the statistical
13
analysis system software JMP 11.0.0 (SAS Institute Inc, Cary, NC).
15
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Results
Patients’ Characteristics and Surgical Data
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Table 1 shows the patients’ characteristics and surgical data. Of the study population, there were
18
47 men and 25 women; the mean age was 62.9 ± 12.9 years (range, 33–87 years). The
19
preoperative electrocardiogram revealed atrial fibrillation in 16 patients. Fifty-nine patients
20
were designated as New York Heart Association functional class I or II, and 13 were designated
21
as class III or IV. In terms of preoperative characteristics, no differences were observed between
22
the chordal replacement and leaflet resection groups. With respect to surgical data, the superior
23
transseptal approach and TAP were performed more frequently in the chordal replacement group
24
than in the leaflet resection group (each parameter P < 0.001). Meanwhile, the Cosgrove ring
25
was used more frequently in MV repair with leaflet resection than in that with chordal
26
replacement (P < 0.001). The mean annuloplasty ring size was observed to be 28.4±1.4 mm for
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both groups (P = 0.975). Although the aortic cross-clamping time was comparable between both
2
groups (P = 0.096), the cardiopulmonary bypass time was significantly longer in the chordal
3
replacement group than that in the leaflet resection group (P = 0.011). No perioperative or
4
hospital deaths were recorded.
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5 Hemodynamic Data
7
The preoperative and postoperative hemodynamic data for MV repair with chordal replacement
8
or leaflet resection are shown in Table 2. The LVMI significantly decreased early after surgery
9
for both the chordal replacement and leaflet resection group (each P
