Download Prediction of left ventricular ejection fraction 6 months after surgical

European Heart Journal – Cardiovascular Imaging (2012) 13, 922–930
doi:10.1093/ehjci/jes068
Prediction of left ventricular ejection fraction
6 months after surgical correction of organic
mitral regurgitation: the value of exercise
echocardiography and deformation imaging
Erwan Donal 1*, Sophie Mascle 1, Anne Brunet 1, Christophe Thebault 1,
Herve Corbineau 2, Marcel Laurent 1, Alain Leguerrier 2, and Philippe Mabo 1
1
Department of Cardiology, CIT-IC 804, INSERM U1099 LTSI, Hospital Pontchaillou-University Medical Center, Rue Henri-Le-Guillou, Rennes 35033, France; and
Department of Cardiovascular Surgery, CHU Pontchaillou, Rennes 35033, France
2
Received 29 January 2012; revised 7 March 2012; accepted after revision 13 March 2012; online publish-ahead-of-print 14 April 2012
Aims
Left ventricular (LV) end-systolic diameter and LV ejection fraction (LVEF) are correlated with postoperative LVEF
and prognosis in patients with organic mitral regurgitation (MR). However, in some patients, the LVEF does not
return to normal 6 months postoperatively, despite normal preoperative diameters. Thus, our study aimed to evaluate whether preoperative LV strain values assessed by echocardiography at rest and during exercise were predictors
of postoperative LVEF at 6-month follow-up in patients undergoing surgery for severe organic MR.
.....................................................................................................................................................................................
Methods
In total, 88 patients with severe organic MR (mean age 62.6 + 1.4 years) were prospectively recruited. All patients
and results
underwent an echocardiogram at rest and submaximal exercise (110 + 10 bpm) prior to surgery and then at rest
6 months after surgery. Exclusion criteria were significant coronary artery disease, other organic valvular diseases,
uncontrolled arrhythmia, and haemodynamic instability. Among the 88 patients, 77 had complete data sets with
rest and exercise echocardiograms and underwent isolated mitral valve surgery (repaired, n ¼ 72). Global longitudinal
strain (GLS) at rest (R ¼ 20.42, P ¼ 0.011) and during exercise (R ¼ 20.36, P ¼ 0.034) correlated with postoperative
LVEF. When normalized for LV end-systolic diameter, GLS during exercise was more closely correlated with postoperative LVEF and was its best predictor based on a multivariate linear regression model. At a cut-off of 25.7%/cm,
sensitivity was 0.83, specificity 0.70, negative predictive value 0.64, and positive predictive value 0.86 for predicting a
6-month postoperative LVEF of ,50%.
.....................................................................................................................................................................................
Conclusion
In patients undergoing surgery for severe organic MR, GLS normalized for LV end-systolic diameter at submaximal
exercise may be used as a predictor of postoperative LVEF.
----------------------------------------------------------------------------------------------------------------------------------------------------------Keywords
Mitral regurgitation † Exercise stress echocardiography † Global longitudinal strain † Left ventricular function
Introduction
Determining the optimal timing for patients with severe organic
mitral regurgitation (MR) to undergo mitral valve repair remains
a challenge.1,2 Preoperative left ventricular (LV) systolic function
and LV end-systolic diameter (LVeSD) are important postoperative prognostic factors.3 – 6 According to European recommendations,7 in asymptomatic patients, surgical repair should
be proposed if the LV ejection fraction (LVEF) is ,60% or
LVeSD reaches 45 mm.
However, the LVEF is not a sensitive parameter of LV systolic
function, being too load-dependent. In severe MR, LV afterload is
low, resulting in a preserved LVEF even in the advance stages of
the disease despite a decrease in LV systolic function. Therefore,
predicting postoperative LVEF in patients undergoing surgical
correction of MR is still challenging.8,9
* Corresponding author. Tel: +33 (0) 2 99 28 25 25; fax: +33 (0) 2 99 28 25 10, Email: [email protected]
Published on behalf of the European Society of Cardiology. All rights reserved. & The Author 2012. For permissions please email: [email protected]
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Mitral regurgitation and exercise stress echocardiography
Submaximal exercise may be an effective means to detect LV
systolic dysfunction or, at least, demonstrate the absence of contractile reserve. Moreover, longitudinal myocardial function was
shown to be more sensitive than the LVEF in detecting disturbances in LV function.10 An assessment of longitudinal myocardial
function using speckle tracking was previously proposed, and this
may be applied during submaximal exercise.11
The aim of our study was to determine whether preoperative
LV longitudinal strain values assessed at rest and during submaximal stress echocardiography were able to identify preoperative
LV systolic dysfunction and predict postoperative LVEF in patients
undergoing surgical correction for severe organic MR.
Methods
Patients
Between 2008 and 2010, 88 out of 120 solicited patients were prospectively recruited at our university hospital. All patients with degenerative MR (fibroelastic degeneration or Barlow disease) and
scheduled to undergo mitral valve surgery were eligible for inclusion
in the study. The 2007 European recommendations were used as a
guideline to determine the indications for surgery.3 Asymptomatic
patients with severe MR but without other formal indications for
surgery [i.e. LVEF ,60%, LVeSD .45 mm, atrial fibrillation, or systolic
pulmonary artery pressure (sPAP) .50 mmHg at rest] were also proposed to undergo surgery, if there was a high likelihood of mitral valve
repair and low operative risk. Patients with non-significant coronary
artery disease on preoperative angiography were also included, as
they did not justify any revascularization treatment. Exclusion criteria
were the following: age ,18 years, MR of ischaemic or functional
origin, haemodynamic instability, requirement for urgent surgery, uncontrolled arrhythmias, and patient refusal (patients were requested
to return to our tertiary centre for follow-up 6 months after
surgery, which is not the standard practice). Each patient gave his or
her signed consent after receiving written and oral study information.
The study was approved by an ethics committee (Person Protection
Committee West V) (PIME 08/16-675).
After enrolment in the study and prior to surgery, the patients
underwent a detailed evaluation, involving a clinical evaluation,
12-lead resting electrocardiogram, resting echocardiogram, and exercise echocardiogram.
Echocardiography
The resting echocardiography was performed using a GE ViVid scanner
(General Electric Healthcare, Horten, Norway), while secondary data
analysis was carried out with the EchoPAC software (General Electric
Healthcare, Horten, Norway). Multiple parameters were analysed
during the resting echocardiography. Measurements of LV end-diastolic
diameter (LVeDD) and LVeSD were obtained from M-mode analysis
using the left parasternal long-axis view. MR was quantified using a multiparametric approach: measurement of the effective regurgitant orifice
(ERO) and regurgitant volume using the proximal isovelocity surface
area, measurement of the vena contracta, analysis of the mitral to
aortic velocity-time integral ratio, and study of the pulmonary venous
reflux.12 The LVEF was measured using the modified Simpson’s biplane
method. Tissue Doppler was used to measure systolic velocity (S′ ) at
the septal and lateral sites of the mitral annulus. Deformation analysis
using two-dimensional strain was performed, as it represents a promising
technique for evaluating LV systolic function. Two-dimensional grey scale
images were acquired in standard apical four-, three-, and two-chamber
views at a frame rate of 80 frames/s (mean 89 + 4 frames/s). LV was
divided into 17 segments, with each segment being individually analysed.
Using a dedicated software package (EchoPAC PC), average global longitudinal strain (GLS) was calculated automatically. Two-dimensional
strain is a non-Doppler-based method for evaluating systolic strain
using standard two-dimensional acquisitions. After placing three endocardial markers in an end-diastolic frame, the software automatically
tracked the contour on subsequent frames. Adequate tracking was verified in real time and corrected by adjusting the region of interest or
manually correcting the contour to ensure optimal tracking. Twodimensional longitudinal strain was assessed in apical views, with the
average longitudinal strains being calculated for the 16 segments.13
However, this measurement was load and geometry dependent. Thus,
we evaluated an index that combined the GLS and LVeSD.14
Diastolic LV function was evaluated by analysing the E- and A-waves
of mitral inflow. Early diastolic velocity (e′ ) was acquired using pulsed
tissue Doppler at the septal and lateral sites of the mitral annulus. Endsystolic left atrial (LA) volume was obtained with Simpson’s biplane
method. sPAP was estimated based on the systolic gradient between
the right ventricle and right atrium.
An exercise echocardiogram was performed in a semi-supine position on a tilting exercise table. After an initial workload of 30 W for
2 min, workload was increased by 30 W every 2 min. Blood pressure
and 12-lead ECG were continuously recorded. Two-dimensional
Doppler echocardiography was performed in the same manner as
that recorded at rest during the entire exercise duration. The data
obtained for a stable heart rate (120 bpm) was used for the analysis
(Figure 1).
As stipulated at the time of inclusion in the study, each patient was
asked to return for a follow-up rest echocardiogram obtained 6 + 1
months after surgery. Intra- and inter-observer reproducibility as
well as test and re-test variability were recently reassessed in our laboratory,15 especially for strain analysis.
Patients were divided into two subgroups based on their postoperative LVEF. Group A included patients with a postoperative
LVEF ≥50%, whereas group B included those with LV dysfunction
and postoperative LVEF ,50%.
Statistical analysis
Quantitative data were expressed as mean + standard deviation and
qualitative data as numbers and percentages. Student’s t-test was
used to compare the means between independent samples, whereas
paired Student’s t-test was employed for intra-group comparisons.
The comparisons of qualitative variables were performed using x2
test. The Pearson test was used to assess correlations. Receiver operating characteristic (ROC) curves were constructed to determine the
sensitivity and specificity of pre-operative parameters to predict
6-month postoperative LVEF.
Stepwise multiple regressions were used to assess whether parameters obtained from the preoperative exercise stress echocardiography could predict 6-month postoperative LVEF. A logistic
regression model was used to define the predictive parameters of
LV dysfunction 6 months after surgical intervention. The level of statistical significance was set at P , 0.05.
Results
Patient population
In total, 88 patients were enrolled in this study, but complete data
sets at rest and during exercise were only available for 77. Thus,
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E. Donal et al.
Figure 1 Assessment of global longitudinal strain at rest and during submaximal exercise in a patient with severe organic mitral regurgitation.
Global longitudinal strain in the apical four-chamber view increased from 218.8 to 225.5% in this example.
Table 1
Patient characteristics
Characteristics
Total population (n 5 77)
Group A (n 5 65)
Group B (n 5 12)
P-value
0.34
...............................................................................................................................................................................
Clinical
Age (years)
63 + 16
64 + 13.3
62 + 18
Sex (male) (%)
59 (67)
45 (61.6)
14 (93.3)
0.01
AFib (%)
Hypertension (%)
15 (17)
38 (44)
11 (15)
32 (46.3)
4 (26.6)
6 (40)
0.27
0.65
Diabetes (%)
3 (3.5)
2 (2.8)
1 (6.6)
0.46
BMI (kg/m2)
NYHA (I/II/III/IV)
25 + 4
28/53/6/1
25 + 4
25/43/4/1
25 + 4
3/10/2/0
0.9
0.5
Coronary heart disease (%)
13 (15)
10 (13.7)
3 (20)
0.53
37 (42)
31 (42.5)
6 (40)
0.86
42 (48)
34 (46.5)
8 (53)
0.63
30 (35)
25 (35.2)
5 (33.3)
0.89
ECC (min)
109 + 40
109.7 + 42.2
104.1 + 27.3
0.66
Clamping (min)
80 + 29
80.2 + 30.5
79.5 + 22.4
0.93
Treatment
BB/Ca (%)
ACE inhibitor/ARA II (%)
K-inh/APA (%)
Surgery
Group A: Patients with 6-month postoperative LVEF ≥50%.
Group B: Patients with 6-month postoperative LVEF ,50%.
AFib, history of atrial fibrillation; BMI, body mass index; BB, beta-blockers; Cal, calcium channel antagonists; ACE, angiotensin-converting enzyme; ARA II, angiotensin-II receptor
antagonists; K-inh, vitamin K inhibitor; APA, anti-platelet treatment: ECC, extra-corporeal circulation.
the analysis was performed using the data from these 77 patients.
A higher prevalence of males was found in the group of patients
with postoperative LV dysfunction, with this difference being statistically significant. However, gender was not found to be a predictor of postoperative LVEF at 6-month follow-up in the regression
analysis.
Table 1 summarizes the clinical characteristics of patients at the
time of inclusion in the study. All patients had degenerative MR
with a flail leaflet and all, excepting five, underwent mitral valve
repair. As a separate analysis of these five patients did not affect
the final results, we did not distinguish these patients from the
remaining 72.
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Mitral regurgitation and exercise stress echocardiography
Extracorporeal circulation (ECC) lasted for 109 + 40 min on
average, while the average duration of clamping was 80 +
29 min. The duration of ECC and clamping did not differ
between groups A and B. The postoperative period and duration
of hospital stay were identical in both groups. Furthermore,
there was also no between-group difference in terms of the type
of surgery performed (repair vs. replacement). Surgical revision
after mitral valve repair was required for two patients (one at 2
weeks and the other at 6 months) due to recurrent severe
mitral insufficiency. None of these clinical or surgical characteristics in our population was correlated with LVEF at the 6-month
follow-up.
Echocardiographic data
All patients had severe MR. Preoperative echocardiographic data at
rest and during exercise is provided in Table 2. Based on the multiparametric evaluation described above, all of the patients in this
study presented severe MR (Grade 3-4/4).
Comparison of echocardiographic
parameters according to postoperative
LVEF
Table 3 summarizes the comparisons of echocardiographic parameters. An overall reduction in postoperative LVEF was
observed, with the average preoperative LVEF being 67 + 12%
compared with 54.6 + 7.3% postoperatively (P , 0.001). In
total, 12 patients had a postoperative LVEF ,50% (group B).
These patients with postoperative LV systolic dysfunction presented a more severe LA and LV dilatation in the preoperative
period when compared with patients with normal postoperative
LV systolic function. Table 3 shows the higher values of LA
volume, area, and diameter as well as LVeSD and LVeDD and
volumes in patients with postoperative LV systolic dysfunction.
Notably, no differences were observed between patients with
normal and reduced postoperative LVEF in terms of preoperative
LVEF at rest or during exercise and LV S′ at rest. However, preoperative LV GLS values at rest and during exercise were poorer
in patients with postoperative LV systolic dysfunction, with this
difference being statistically significant. Moreover, when normalized for LVeSD, preoperative LV GLS values at rest and during
exercise were still statistically lower in patients with postoperative LV systolic dysfunction. Among these patients, six
had class I indications for surgery according to the European
Society of Cardiology criteria, with five patients presenting
LVEF ≤60% and one Stage III heart failure according to the
New York Heart Association classification. None of the patients
had LVeSD ≥26 mm/m2. Patients with postoperative LV dysfunction had a more dilated left atria compared with patients with
normal LVEF (50 + 21 vs. 64 + 3 mm, respectively; P ¼ 0.022).
These patients also had more dilated LV at the end-systole
(LVeSD: 35 + 6 vs. 40 + 5mm; P ¼ 0.004) and end-diastole. Preoperative sPAP at rest was higher among group B patients. Preoperative LVEF did not differ between the two groups at the
time of inclusion. However, the LV GLS varied more widely
among the patients with postoperative LV dysfunction (220 +
3 vs. 217 + 2%; P ¼ 0.012).
Table 3 Differences in the echocardiographic
parameters between groups A and B
Gp A
Exercise stress echocardiography data
Variable (n 5 77)
Mean + SD
................................................................................
Workload (W)
Blood pressure (mmHg)
71 + 28
Rest: 132/78, exercise 168/87
HR (bpm)
Rest: 73 + 13, exercise 119 + 19
LV EF (%)
Exercise LV EF (%)
67 + 12
71 + 12
GLS (%)
218 + 5
Exercise GLS (%)
SPAP (mmHg)
221 + 6
38 + 12
Exercise sPAP (mmHg)
58 + 17
HR, heart rate; LA Vol, left atrial volume; LVeSD, left ventricular end-systolic
diameter; sPAP, systolic pulmonary artery pressure; GLS, global longitudinal strain.
P-value
(A vs. B)
................................................................................
Left atrium (LA)
LA-vol (mL/m2)
50 + 21
64 + 33
0.022
LA-area (cm2)
LA-diam (mm)
25 + 8
44 + 8
31 + 9
50 + 9
0.013
0.005
LVeSD (mm)
LVeSD (mm/m2)
35 + 6
20 + 3
40 + 5
21.5 + 3
0.004
0.019
LVeDD (mL)
55 + 7
60 + 6
0.01
LVeSV (mL)
LVeDV (mL)
50 + 23
144 + 48
63 + 20
175 + 37
0.028
0.018
E (cm/s)
128 + 32
127 + 30
0.4
9+3
9.5 + 2
0.4
Left ventricle (LV)
LV-S′ (cm/s)
LVEF (%)
66 + 7
64.5 + 10
0.2
LVGLS (%)
ExGLS (%)
71 + 6
220 + 3
69 + 10
217 + 2
0.17
0.012
LVGLS/LVeSD (%/mm)
Ex.LVEF
Table 2
Gp B
222 + 4
218.5 + 4.5
0.001
Ex LVGLS/LVeSD
(%/mm)
26 + 1
24.4 + 1
0.001
Right ventricle
27 + 2
25.2 + 1
sPAP (mmHg)
TAPSE (mm)
35 + 9
22 + 4
Stric (cm/s)
14 + 4
46.5 + +17
24 + 5
16 + 3
0.001
0.001
0.03
0.05
LA-vol, left atrial volume; LA-diam, Left atrial diameter in parasternal long-axis
view; LVeDD, left ventricular end-diastolic diameter; LVeDV, left ventricular
end-diastolic volume; LV-S′ , average of systolic velocities (S′ ) obtained using pulsed
tissue Doppler at the septal and lateral sides of the mitral annulus; ExGLS, global
longitudinal strain during exercise; Stric, systolic velocity (S′ ) obtained using pulsed
tissue Doppler at the tricuspid annulus; TAPSE, tricuspid annulus plane systolic
excursion.
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Table 4 Pearson correlation coefficient between the
preoperative echocardiographic parameters and
6-month postoperative LVEF
Variables
Pearson correlation
coefficient
P-value
LA diameter
Indexed LA volume
20.339
20.350
0.047
0.039
LVeDD
20.354
0.037
LVeSD
Exercise LVeSD
20.338
20.508
0.047
0.002
Indexed LVeSD
20.325
0.057
LVeDVol
LVeSVol
20.345
20.336
0.043
0.048
................................................................................
LV EF
0.302
0.078
Exercise LV EF
GLS
20.058
20.422
0.739
0.011
Exercise GLS
20.360
0.034
GLS/LVeSD
Exercise GLS/LVeSD
20.469
20.534
0.004
0.001
sPAP
20.133
0.445
The abbreviations are the same as those in Table 3.
Correlations between preoperative
ultrasound parameters and postoperative
LVEF
Table 4, Figures 2, and 3 present the preoperative parameters considered to impact postoperative LVEF along with their Pearson
correlation coefficients (r). Although statistically significant, the
values of the correlation coefficients for GLS at rest and exercise
were low, but better when normalized for LVeSD. However, a
better correlation coefficient was found for GLS/LVeSD during
exercise. The results from the ROC curve (Figure 2) analysis are
provided in Figure 3 and Table 5. GLS/LVeSD with a cut-off of
25.7%/cm had the best predictive value, with a negative predictive
value of 0.64 and positive predictive value of 0.86.
Determinants of postoperative LVEF
In stepwise multivariate linear regression analysis, GLS normalized
to LVeSD during exercise was the best parameter for predicting
postoperative LVEF (Table 6).
Discussion
Determining the optimal timing of surgery prior to the development of LV dysfunction and progression of symptoms is critical,
as prognosis after surgery is poor in patients with permanent LV
Figure 2 Linear regression analysis. (A) Correlation between GLS (global longitudinal strain) and 6-month postoperative left ventricular ejection fraction (LVEF). (B) Correlation between the indexed left ventricular end-systolic diameter (LVeSD) and 6-month post-operative left ventricular ejection fraction (LVEF). (C ) Correlation between GLS (global longitudinal strain) during exercise and 6-month post-operative left
ventricular ejection fraction (LVEF). (D) Correlation between GLS (global longitudinal strain) during exercise and normalized for LVeSD and
6-month post-operative left ventricular ejection fraction (LVEF).
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Figure 3 Receiver operating characteristic curves for: (A) Global longitudinal strain (GLS). (B) Left ventricular end-systolic diameter (LVeSD).
(C ) GLS during exercise. (D) GLS/LVeSD during exercise.
Table 5
Receiver operating characteristic curve analysis
LVeSD (mm)
Indexed LVeSD (mm/m2)
Rest GLS (%)
Exercise GLS (%)
Exercise GLS/LVeSD (%/mm)
38
0.74
19.4
0.55
218
0.77
219
0.88
25.7
0.83
Specificity
0.65
0.83
0.56
0.61
0.70
PPV
NPV
0.85
0.51
0.88
0.44
0.80
0.52
0.84
0.70
0.86
0.64
...............................................................................................................................................................................
Best cut-off value
Sensitivity
Best cut-off values along with their sensitivity, specificity, and positive and negative predictive values.
damage.2,7,16,17 In this study, we showed that LV systolic longitudinal deformations (GLS) measured at rest and during submaximal exercise gave greater weight to LVeSD than the LVEF in predicting
postoperative LV function.
Indications for mitral surgery and
controversies
The standard criteria for surgery in patients with severe organic MR
include the presence of severe symptomatic MR or LV dysfunction
(LVEF ,60%, LVeSD ≥45 mm, atrial arrhythmias, or SPAP
≥50 mmHg). However, among patients for whom surgical decisions
were based on these criteria or mitral valve repair was considered
feasible, LV dysfunction may still occur even after mitral valve
repair. A recently published paper by Tribouilloy et al. 18 effectively
demonstrated not only the value of LVeSD, but also its limitations
in sensitivity and specificity for predicting postoperative LVEF. To
date, a randomized study is yet to be conducted in order to guide
the treatment procedure for asymptomatic patients with MR.
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E. Donal et al.
Table 6
Multivariate regression analysis results (linear and logistic)
Parameter
Value
Standard
deviation
Pr > |t|
t
Inferior limit
(95%)
Superior
(95%)
...............................................................................................................................................................................
Multivariate linear regression analysis
Constante
,0.0001
0.425
0.092
4.640
0.000
20.003
0.000
0.002
21.400
21.265
LV EF
0.002
0.001
1.819
0.073
0.000
0.004
sPAP
GLS
20.001
20.003
0.001
0.002
21.357
21.382
0.179
0.171
20.002
20.007
0.000
0.001
20.009
0.004
22.405
0.019
20.017
20.002
Khi2 Wald
Pr . Khi2
Wald inf. limit
(95%)
Indexed LA Vol
Indexed LVeSD
Exercise GLS/LVeSD
Parameter
Logistic regression analysis
Indexed LA volume
0.166
0.210
0.242
0.608
20.001
20.008
0.000
0.002
Wald sup. limit
(95%)
0.941
0.332
20.204
0.605
Indexed LV eSD
4.143
0.042
20.786
20.015
LVEF
sPAP
1.767
3.395
0.184
0.065
20.624
20.644
0.120
0.020
Rest GLS
4.829
0.028
0.047
0.825
Exercise GLS/LVeSD
0.179
0.672
20.659
0.425
The abbreviations are the same as those in Table 3.
Consequently, the existing recommendations3 are causing controversy as to the optimal time for surgical intervention in such
patients.19,20 In certain patients, the assessment of longitudinal
strain both at rest and during submaximal exercise may help in the
decision-making process as to whether or not to propose a mitral
valve repair.
Prediction of postoperative LV
dysfunction
In severe MR, chronic LV dilatation and eventually eccentric hypertrophy occur so as to accommodate the additional regurgitant
volume and maintain LV outflow. End-systolic volume and wall
stress increase, leading to LV dysfunction, which may be irreversible if the myocytes are replaced with subendocardial fibrosis.
Conventional LVEF was normal in all of our patients as a result
of the considerable load dependence. Deformation imaging was
considered a more sensitive index of LV systolic function than
the LVEF. However, even after assessing the robustness and reproducibility of this component of LV deformation, we are still addressing the load-dependent indices.21 In addition, longitudinal strain is
considered to be geometry dependent.14,22 Marciniak et al. proposed the normalization of strain values for LV dimensions. In
our study, linear multivariate regression analysis led us to conclude
that GLS recorded during exercise and normalized for LVeSD was
the best predictor of 6-month postoperative LVEF. The importance of this result is emphasized by the fact that all of our patients
had severe MR, although most were asymptomatic or mildly symptomatic, without conventional LVEF dysfunction or obvious enlargement. We applied an ‘early surgery’ strategy based on the
feasibility of mitral repair as well as the patient’s wishes, rather
than the ‘watchful waiting’ approach.1,20 Despite this ‘aggressive
strategy’, postoperative LV dysfunction was still observed in 12
patients 6 months after surgery. Our results are in line with
recent evidence in favour of early surgery.22 – 24 For patients with
postoperative LV dysfunction, preoperative evaluation showed
that the atrial and ventricular cavities were more dilated. A
recent study also showed that a high preoperative estimation of
sPAP (.50 mmHg) using echocardiography at rest and during exercise was an independent prognostic factor for postoperative
morbidity and mortality.25 However, in our specific population,
these factors were less powerful predictors of postoperative LV
dysfunction than LVeSD or deformation indices (strains).
Value of systolic function indices: LVEF
and LV GLS
Preoperative LVEF ,60% was previously shown to be associated
with a higher risk of postoperative cardiac events, including
cardiac mortality.2,5 However, among the patients in our study
undergoing an early operation, we were not able to determine
the prognostic value of load-dependent, preoperative LVEF.8
Other tools for assessing LV systolic function have been suggested;
notably, measurements of myocardial deformation, particularly the
longitudinal component, may be useful in evaluating systolic function. This parameter was considered one of the earliest altered
indicators in the case of systolic dysfunction, with a simple and reproducible measurement.26,27 In our study, patients with postoperative LV dysfunction had larger alterations in preoperative
LV GLS at rest and during submaximal exercise compared with
those with normal postoperative LVEF. These results suggest
that GLS may be more sensitive than the LVEF in detecting
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Mitral regurgitation and exercise stress echocardiography
latent LV dysfunction in patients with severe MR. Lancellotti et al.
demonstrated that in asymptomatic patients with degenerative MR,
subnormal LV function may be reliably identified using twodimensional strain imaging. Limited exercise LV longitudinal contractile recruitment during exercise was also found to be correlated with postoperative LV dysfunction.9 Additionally, Marciniak
et al. showed that the imaging deformation (strain and strain rate
calculated using tissue Doppler at a high frame rate) was improved
compared with the Simpson measure of LVEF for predicting LVEF
after mitral repair.10
New perspectives
Current European recommendations3 are based on LVeSD measurements and LVEF analysis using the biplane Simpson technique
in order to determine whether surgery should be proposed to
patients with degenerative MR. Regarding the clinical decisionmaking process,28,29 we believe that indicators such as pulmonary
arterial hypertension,30 atrial fibrillation,31 dilation of the left
atrium,25 elevated BNP, and altered VO2 may be useful in a multivariate approach to best determine how early an asymptomatic
patient should be operated on to preserve LV systolic function.
Furthermore, the role of cardiac deformation for the preoperative
evaluation of MR has not yet been fully examined, but recent
studies,9 – 31 including our own, suggest that cardiac deformation
imaging may be a useful method for evaluating preoperative LV systolic function. However, combining this method with a submaximal
exercise stress echocardiography appears to be clinically relevant,
as it is a straightforward way of assessing LV systolic function in
two different haemodynamic conditions, while providing an opportunity to assess the myocardial reserve and its adaptability to
changes in load and stress.
Limitations
This study was limited by its relatively small sample size. However,
this was a prospective study of a selected population of patients.
All patients underwent surgery for severe MR and were considered good candidates for mitral valve repair. This study was
limited to determining via ultrasound the predictive factors of postoperative LV dysfunction 6 months after surgery. More data on the
clinical outcome of such patients should be obtained from complementary studies with extended follow-up.
Conclusions
Determining the optimal timing of mitral valve surgery for asymptomatic severe degenerative MR remains controversial. The practice of observing patients with severe MR and waiting for
symptoms or echocardiographic evidence suggesting LVEF
changes has been questioned in many studies, which demonstrated
the benefits of conservative surgery in patients with severe regurgitation or LVeSD .40 mm (or even as low as 37 mm). This study
added to the existing data by demonstrating that preoperative LV
GLS normalized for LVeSD during submaximal exercise had an
additional and independent prognostic value beyond LVEF and
LVeSD. This parameter may be used as a predictor of
postoperative LV systolic function in patients undergoing surgery
for severe organic MR.
Acknowledgements
The authors would like to acknowledge Marie Guinoiseau, Valérie
Le Moal, and Marcel Laurent for their support in recruiting the
patients. In addition, we would like to thank CHU Rennes for
the grant given to conduct the study.
Conflict of interest: none declared.
Funding
We obtained a grant from Rennes University Hospital (COREC).
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doi:10.1093/ehjci/jes111
Online publish-ahead-of-print 31 May 2012
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An abnormal echo-bright structure seen in the ascending aorta: right
coronary artery stent protrusion
T.A.C. Snow*, J. Voss, P.N. Ruygrok, and S.C. Greaves
Green Lane Cardiovascular Service, Auckland City Hospital, Auckland, New Zealand
* Corresponding author. Tel: +6421353523, Email: [email protected]
These images are from the
post-procedure transoesophageal echocardiogram of a
43-year-old female who was admitted to our unit for primary
percutaneous coronary intervention (PCI) following diagnosis of an inferior ST-elevation
myocardial infarction (MI). She
had a complicated procedure
due to agitation and eventually
received two Promus Element
stents measuring 3.0 × 32 mm
Figure 1 Short- and long-axis transoesophageal images showing stent protrusion from right coronand 3.5 × 12 mm to the ostium
ary sinus.
of the right coronary artery
(RCA).
The transthoracic echocardiogram outlined a 16 × 6 mm echo-bright slightly mobile structure in the aortic root close to the origin
of the RCA. She underwent transoesophageal echocardiography to further identify this mass and to exclude a potential embolic cause
of her MI.
The transoesophageal echocardiogram identified the mass as exaggerated protrusion of the stent into the aortic root which on
review of the angiography images occurred due to the patient taking an unexpected deep breath in during stent deployment.
The patient was discharged on lifelong aspirin and clopidogrel to reduce the risk of potential thrombus formation.
Supplementary data are available at European Journal of Echocardiography online.
Published on behalf of the European Society of Cardiology. All rights reserved. & The Author 2012. For permissions please email: [email protected]