nghiên cứu một số thông số huyết động và chức năng tim bằng siêu âm doppler ở bệnh nhân phẫu thuật thay van hai lá sorin bicarbon bản tóm tắt tiếng anh

INTRODUCTION
1. The necessaty of the thesis
Mitral valve replacement is the last choice for treating mitral
valve diseases if the valve lesions are too severe for preservation.
In VietNam, valve replacement surgery has been carried out
for more than 10 years, but the number of the patients receiving valve
prostheses has incessingly increased. The number of valve
replacement operation actually has reached 100 cases per month,
among which, nearly a half are single mitral valve.
However well prosthetic valves have been improved, patients risk
many complications: thrombosis, infective endocarditis, prosthetic
degeneration,…Therefore, these patients need to be followed up
periodically to find out these complications as early as possible.
Echocardiography is an established technique for postoperative routine
serial assessment of hemodynamics, ventricular function as well as valve
operation. Around the world, there have been many studies on prosthetic
valve operation as well as on evaluating the postoperative
hemodynamics and cardiac function changes by echocardiography. In
our country, there are a few previous studies on normally functioning
prostheses using mainly transthoracic Doppler echocardiography. We
have not seen any studies using transesophageal echocardiography to
assess the activity of the prosthetic valve. Therefore, to study this
problem is topical, scientific and helpful to cardiologists in clinical
practice.
2. The significance of topics
Heart valve replacement surgery is done more and more now.
This is an effective treatment to improve symptoms and survival of
patients. Hemodynamics has been improved, pulmonary pressure and
heart failure have been reduced in the majority of patients. However,
1
some patients may also manifest heart failure as well as the

complications of prosthetic valve. Echocardiography plays an
important role and is one of the major techniques for monitoring
patients. Echocardiography research on outcome after prosthetic
valve replacement is really meaningful for prognosis and monitoring
patients after surgery.
3. Objectives of the study
- To study the changes of hemodynamics and cardiac function
after surgical mitral valve replacement with Sorin Bicarbon valve.
- To evaluate the normally functioning and complications (if
any) of prosthetic mitral valve Sorin Bicarbon by transthoracic and
transesophageal echocardiography.
4. Structure
The thesis consists of 105 pages (excluding appendices and
references) with 4 main chapters: Introduction - 2 pages , Chapter 1 -
Overview 28 pages, Chapter 2 - Subjects and Methods 16 pages,
Chapter 3 - Research Results 31page, Chapter 4 - Discussion 25
pages, Conclusions and Recommendations - 3 pages. Thesis has 37
tables, 7 diagrams, 26 illustrations, 149 references, including 33
Vietnamese and 116 English and French documents.
Chapter 1
OVERVIEW
1.1.Mitral valve diseases and the treatment
1.1.1. Causes and pathophysiology changes in mitral diseases
The mitral diseases include stenosis, regurgitation, and the
combination of stenosis and regurgitation. A common cause is post-
rhumatism. Other causes may be degeneration, annular calcification,
infective endocarditis
2
Mitral stenosis increases the average pressure in the left
atrium, and if severe enough, it leads to secondary pulmonary

hypertension. Long-standing pulmonary hypertension (increased
right ventricular afterload) will lead to the dilatation and remodeling
of the right ventricle, which causes tricuspide annular dilatation and
tricuspide regurgitation.
Mitral regurgitation resuts in LV overload and will cause
chronic left ventricular dilatation. Because of the regurgitant flow
entering the low-impedance left atrium, clinical

indices of myocardial
systolic function, such as ejection fraction (EF)

and fractional
circumferential fiber shortening (FS), can

still be normal even if
severely depressed LV systolic contractility

is present. Chronic
regurgitant flow into the left atrium leads to progressive atrial
enlargement but left atrial pressure is normal or only slightly above
normal. In this situation, pulmonary artery pressure and pulmonary
vascular resistance usually still remain in the normal range or are
only modestly elevated.
In patients with concomitant mitral stenosis and regurgitation,
the left atrium is dilated and intra - atrial pressures increased. Left
atrial thrombosis prevalance is usually less. Long - standing elevated
pressure in the left atrium will increase the pulmonary artery
pressure. Degree of left ventricular dilatation depends on the degree
of regurgitation.
1.1.2. Treatment of mitral valve diseases

Treatment of mitral valve diseases includes medical therapy,
percutaneous balloon dilatation, surgical treatment
(commissurotomy, mitral valve repair, mitral valve replacement).
Over the past 40 years, a large variety of prosthetic valves have
been developed with the aim of improving hemodynamic function,
inceasing durability, and reducing complications. Nevertheless, there
3
is no ideal valve, and all prosthetic valves are prone to dysfunction.
The valve types now implanted include bileaflet and tilting disc
mechanical and biological and autografts (Ross procedure) in which,
Sorin Bicarbon mechanical valves (Sorin Biomedica, Saluggia, Italy)
is one of the most common used bileaflet mechanical prostheses in
the world and in Vietnam.
1.1.3. Diagnostic methods for evaluation of prosthetic valve
function
The currently available modalities in the evaluation of
prosthetic valve function include cinefluoroscopy, cardiac
catheterization, computerized tomography and echocardiography.
With the advent of Doppler and transesophageal imaging,
echocardiography has become the method of choice for the
evaluation of prosthetic valve function. Motion as well as structure of
prosthetic valves and the causes of valve dysfunction (if any) can be
assessed by transthoracic and transesophagial echocardiography.
With the application of Doppler echocardiography, information on
transvalvular gradients, effective areas, and the physiologic and
pathologic valve regurgitation are provided. In addition to valve
function, echocardiography offers unique information about the
anatomy of the cardiac structures adjacent to the prosthesis as well as
cardiac size and function and an estimate of pulmonary artery
pressure.

1.2. STUDY ON THE CLINICAL AND HEMODYNAMIC
CHANGES AFTER MITRAL VALVE REPLACEMENT
SURGERY
1.2.1. Around the world
There are many studies on different aspects of mitral
prosthetic valve:
- The early and longterm clinical experiences of the different
4
types of prostheses: Goldsmith (1999), Camilleri (2001), Borman
(2003), Ikonomidis (2003), Misawa (2007), Palatinos (2007)
- Study of normal Doppler echocardiographic characteristics of
different prostheses: Badano (1997), Reisner (1998), Joseph (2005),
review of Rosenhek (2003) The role of transesophageal
echocardiography in detection the causes of prosthetic malfunction:
Muratori (2006), Ozkan (2006), Pedersen (2010) :.
- The study of Doppler echocardiographic changes in left
ventricular size and function and / or pulmonary pressure after mitral
valve replacement: Le Tourneau (2000), Chowdhury (2005), Zakai
(2010), Aris (1996), Mubeen (2008)
1.2. In Vietnam
In 2005, Nguyen Hong Hanh studied normal Doppler
echocardiographic characteristics of St. Jude valve. Research of Ho
Huynh Quang Tri (2007), Dang Hanh Son (2010) for clinical and
echocardiographic medium-and long-term experiences of the patients
after mitral replacement surgery. The majority of patients had
improved NYHA grade, pulmonary pressures, cardiac chamber
sizes, Researches by Nguyen Duy Thang (2011), Nguyen Hong
Hanh (2012) shows the good results of mitral valve St Jude
replacement with low complication rates. Research in 2012 by
Nguyen Hong Hanh showed the 6 months’ improvement of clinical

and subclinical improved. These studies did not analyze the changes
in echocardiographic in detail nor performe transesophageal
echocardiography.
5
Chapter 2.
SUBJECTS AND METHODS
2.1. SUBJECTS
The study population consisted of 104 patients undergoing
mitral valve replacement using mechanical Sorin Bicarbon prostheses
in Hanoi Heart Hospital between 9/2008 and 11/2009. All patients
were followed up to 6 months. There were 80 patients assessed at 1
year’s post-operative time.
2.1.1. Selection criteria
All patients with mitral valve lesions (stenosis, regurgitation or
mixed lesion) undergoing successful mitral valve replacement
surgery using Sorin Bicarbon prosthses with or without tricuspid
valve repaired were invited to the study.
For the purpose of accurate data analysis, the patients were
divided into 3 groups based on their predominant hemodynamic
valve lesion:
- Group I: dominant mitral stenosis: included 32 patients with
severe miral stenosis (MS) with/out slight MR (≤ 1/4) w/o light aortic
valve lesion.
- Group II: dominant mitral regurgitation: included 35 patients
with severe MR, and may have mild MS w/o mild aortic valve
lesion.
- Group III: mixed mitral valve lesion: included 40 patients
with severe MS and MR grade ≥ 2/4 w/o mild aortic valve lesion.
2.1.2. Exclusion criteria
The patients with concomitant procedure, such as aortic valve

replacement, coronary bypass surgery, congenital heart defects
corrected were excluded from the research.
6
2.2. METHODOLOGY
2.2.1. Study design:
This is a prospective, cross-sectional, longitudinal follow-up study.
2.2.2. Steps:
+ Preoperative assessements: preoperative bilan including physical
examination, chest X-ray, 12-lead ECG, transthoracic
echocardiography and blood sample was completed within 1
week before operation.
+ The patients underwent mitral valve replacement with cardio - pulmonary
bypass and had tricuspide repaired if indicated. Operative
parameters were noted.
+ Postoperative assessements: were carried out at the time of
1-2 weeks, 1 month, 3 months, 6 months after operation or when
there is suspicious symptoms. Note the results of clinical examination
and echocardiography in patients’ records. TEE were performed
within 1 month of the operation or when there were suspected
mechanical valve malfunction or endocarditis.
2.2.3. The echocardiographic data
A. Transthoracic echocardiography Doppler
Transthoracic echocardiography Doppler was performed in a
standard manner using a Nemio 30 ultrasonoscope (Toshiba,
Japan).
* The following parameters were noted in preoperative examination:
- The left ventricular end-diastolic diameter (Dd) and end-systolic
(Ds), fraction of shortening (FS) and ejection fraction (EF).
- The mitral valve lesions (stenosis, regurgitation, mixed lesion).
- Grade of tricuspide regurgitation and pulmonary systolic pressure.

- The diameter and area of the atria, right ventricular diameter,
Tricuspid annular plane systolic excursion (TAPSE), systolic
7
tissue Doppler signal of the tricuspid annulus (St).
* The following parameters were noted in all postoperative
echocardiography - Doppler checkup:
- All parameters evaluated before operation and some other
parameters to assess the functioning of prostheses: maximal and mean
trans – prosthetic gradients (Gmax and Gmean, Vmax and Vmean), the
pressure half time (PHT), effective orifice area (EOA), assessing the
physiological prosthetic regurgitation, pericardial effusion.
B. Transesophageal echocardiography
We noted the parameters evaluating the functioning of
prosthetic heart valves: peak and mean transprosthetic gradients and
velocity (Gmax and Gmean, Vmax and Vmean), the pressure half
time (PHT), effective orifice area (EOA), the physiological and
paraprosthetic prosthetic regurgitation (if any).
* The values of echocardiographic parameters were averaged
over 5 cardiac cycles in patients with atrial fibrillation.
2.4. Statistical analysis
The data collected were treated using SPSS 15.0 software
program.
The results are expressed as mean ± standard deviation
Using "t" test student and Chi square test to compare results
between groups. Compare ANOVA was used to compare mean
values of 2 groups.
Using a paired t test (Paired - t test) to compare the results
obtained before and after surgery, and TTE and TEE results. A
probability (p) valuesless than 0,05was considered statistically
significant.

Chapter 3
8
RESULTS
3.1. Baseline characteristics of the study group
The research population included 104 patients with mitral
mechanical Sorin Bicarbon inserted from 9/2008 to 11/2009, and
were followed up for 6 months. There were 80 patients assessed at 1
year after operation.
The study group included 64.4% female and 35.6% male.
Their ages ranged from 16 to 6 years( mean 44.2 ± 11.5 years).
All patients were in New York Heart Assocition (NYHA)
functional class II or higher before surgery, among them, 14 patients
(13.5%) in the NYHA III – IV. Preoperative atrial fibrillation was
observed in 80 patients (76.9%), 24 patients (23.1%) maintained
sinusal rhythm.
3.2. Pre-operative Doppler echocardiography data
Most patients in the study had post-rhumatismal lesions on
echocardiography: 84 patients accounted for 80.8%.
The patients had left atrial dilatation (average 56.5 mm).
64.4% of patients had spontaneous contrast echo in the left atria, of
these, 17 (16.3%) observed thrombosis in the left atria and/ or left
atrial appendages. 74 patients (71.2%) had 2+ TR or more. 69.9% of
patients with severe pulmonary hypertension (systolic PAP ≥
60mmHg) and 16 patients (15.4%) had EF <50% before surgery.
3.3. Characteristics of mitral valve replacement operation
In the 104 patients studied, the size of the Sorin Bicarbon valve
used ranged from 25 to 33 and included all the intermediat size. The
most used size were 29 and 31 (63.4%). The concomitant tricuspid
valve repair was performed in 68 patients (65.2%). Left atrial and
appendage thrombosis were dredged in 20 patients. 71 patients

(68.9%) had left atrial appendage sutures.
3.4. Doppler echocardiography data assessing mitral Sorin
9
Bicarbon prostheses
3.4.1. Transthoracic echocardiograhy
An adequate recording of the jet through mitral Sorin Bicarbon
protheses have been obtained in 103 patients because one patient had
early prosthetic valve thrombosis.
Table 3.8 gives the values of some transthoracic
echocardiographic parameters evaluating the prosthetic function
Table 3.8. Doppler data of normally functioning mitral Sorin Bicarbon
prostheses
Variables
mean values (x
±
SD)
Limit values
V max (m/s) 1,5 ± 0,2 1,1 – 2,0
V mean (m/s) 1,0 ± 0,15 0,7 – 1,5
G max (mmHg) 9,9 ± 2,7 4,7 – 16,0
G mean (mmHg) 4,2 ± 1,3 1,5 – 7,5
PHT (ms) 74,1 ±8,1 55 - 96
EOA
PHT
(cm
2
) 3,0 ± 0,3 2,3 – 4,0
VTI (cm) 29,0 ± 7,6 17,7 - 85
EOA
continuaty equation

(cm
2
) 2,2 ± 0,6 1,1 – 3,9
EOA index (EOA /BSA) 1,5 ± 0,4 0,75 – 2,6
VTI
mitral
/ VTI
L
1,5 ± 0,3 0,88 – 2, 66
We do not see the significant difference of the peak and mean
velocities, peak and mean pressure gradients, PHT, VTI, and EOA by
PHT method and continuity equation between the sizes of valves (p>
0.05). On TTE, physiological regurgitations were observed in 83 patients
(80.5%).
3.4.2. Transesophageal echocardiography Doppler
The TEE data were evaluated in 98 patients. The
transprosthetic peak and mean pressure gradients measured by TEE
were lower than that measured by TTE (p <0.001 and <0,05). PHT
also shorter and EOA by PHT method also higher with statistical
significance (p <0.001).
On transesophageal study, 3 physiological regurgitant flows
10
were observed in all 98 patients, including one central and 2
peripheral. The largest flows were usually the peripheral ones. The
mean width at the origin was 2.1 ± 0.3 (mm), the mean jet length was
20.2 ± 4.6 (mm) and the mean jet area was 1.3 ± 0.5 (cm
2
).
On 1 month post-operative TEE study, 10 patients (10.2%) had a
small paraprosthetic regurgitation. There was no regurgitant jet with the

width at the origin > 2.6 mm, the length > 38 mm and the jet area > 3.4 cm
2
.
3.5. Changes of the cardiac size and function after mitral valve
replacement surgery.
Early after operation, left ventricular end-diastolic size (Dd, Vd)
decreased significantly, but the size of left ventricular end-systolic (Ds,
Vs) didnot change significantly (p> 0.05). Therefore, FS and EF reduced
significantly after surgery, as compared with before surgery. At the time
of 6 months and 12 months after surgery, left ventricular end-diastolic
and end-systolic size reduced significantly (p<0.001), and left
ventricular systolic function improved significantly with p <0.001.
Post-operative right ventricular size and function reduced
significantly. The parameters asessing right ventricular systolic function
increased significantly from 3 months after surgery. Systolic pulmonary
artery pressure decreased significantly after mitral replacement surgery
with p <0.001. Pulmonary pressure continued to decline in 6 months and 1
year after surgery but not as much as immediately after surgery (p <0,05).
To further analyze these changes, we divided the study subjects
into three groups: mitral stenosis (MS), mitral regurgitation (MR), and
mixed lesion (MS/MR).
3.5.1. Changes of the cardiac size and function in MS group
Table 3.20 lists the preoperative and postoperative Doppler
echocardiographic variables assessing left ventricular size and function in
the MS group.
11
Table 3.20. Changes of echocardiographic - Doppler parameters
assessing left ventricular size and function in the MS group
Variable Preop M0 M3 M6 M12
n 33 31 33 33 28

Dd
(mm)
46,5 ± 6,9 47,5 ± 6,6 47,2 ± 6,6 46,9 ± 4,7 46,5 ± 4,6
Ds (mm) 31,9 ± 5,8 33,3 ± 4,8 31,4 ± 4,0‡ 31,2 ± 4,0* 30,6 ± 3,4*
Vd (ml) 102,9±32,6 105,9± 40 104,6± 24,4 103,7± 24,4 99,5 ± 21,4
Vs (ml) 43,2 ± 18,7 48,9±24,1 39,9± 12,7* 39,7±12,1* 37,1 ± 9,8*
FS (%) 31,4 ± 4,8 30,4 ± 6,2 33,5 ± 6,1* 33,3 ± 5,0* 34,2 ± 4,7*
EF (%) 59,2 ± 7,1 57,5 ± 9,2 61,7 ± 8,4* 61,6 ± 6,9* 62,9 ± 6,6*
*- p < 0,05; ‡: p = 0,05 compared with early postoperative (M0)
The values of echoardiographic - Doppler parameters evaluating
left ventricular size and function after surgery in the MS groups did not
change significantly with p > 0.05. 12- month postoperative Dd and Vd
showed no significant change but Ds and Vs significantly decreased
from the 3
rd
month and left ventricular systolic function was significantly
improved from this point.
Table 3.22. Data of echocardiographic - Doppler parameters assessing
RV size and function and pulmonary pressure in the MS group
Variable Preop M0 M3 M6 M12
n 33 31 33 33 28
RDd (mm) 25,7±7,5 22,1±3,7 22,3±3,6 22,2±3,7 22,1 ± 3,5
TA (mm) 31,6 ± 7,9 27,1±3,8† 27,5 ± 4,6 27,5 ± 3,9 28,1 ± 4,3
TAPSE (mm) 14,9 ± 4,2 9,4 ± 2,5† 12,2±2,5
§
12,5±2,7
§
13,2±3,5
§
St (cm/s) 9,4 ± 2,0 7,1 ± 1,6† 7,4± 1,2

§
7,5± 1,5
§
8,9 ± 1,6
§
sysPAP (mmHg) 54,3±17,0 36,8±7,4† 35,5 ± 7,8 35,5 ± 8,6 34,6 ± 8,9
†- p < 0,001 compared with preoperation;
*- p < 0,05;
§
- p < 0,001 compared with early postoperative (M0.
In the MS group, right ventricular size and systolic function were
significantly reduced after surgery. Postoperative pulmonary pressure
decreased significantly (p <0.001). During 1 year’s follow-up period, RV
diameter did not change significantly, but the systolic function improved
12
significantly from 3 months after surgery (p <0.001); Pulmonary pressure
tended to decrease more, but not significantly (p> 0,05).
3.5.2. Changes of the left ventricular size and function in the MR group
Table 3.23. Changes of left ventricular size and function in the MR group
Variable Preop M0 M3 M6 M12
n 31 31 31 31 22
Dd (mm) 66,4 ± 13,7 57,7± 11,4
†
55,6 ± 10,2 54,1 ± 9,3 53,8 ± 9,7
Ds (mm) 42,9 ± 10,3 42,5 ± 10,5 40,4 ± 10,4 38,1 ± 9,5* 38,2 ± 10,7*
Vd (ml) 239,1±134,5 173,6± 85,4
†
156,1±74,6 146,6±59,9* 139,7±53,9*
Vs (ml) 89,5 ± 58,7 91,8 ± 58,9 76,2±46,2* 67,2± 42,8* 68,6 ± 47,3*
FS (%) 35,6 ± 5,9 25,9 ± 5,1

†
28,0 ± 6,2* 29,8 ± 6,2
§
30,8 ± 6,6
§
EF (%) 63,5 ± 8,3 49,8 ± 8,5
†
53,3±10,0* 55,7± 10,3* 56,7 ± 12,6*
†- p < 0,001 compared with preoperation;
* - p< 0,05; §

- p<0,001 compared with early postoperative (M0)
Early after surgery, Dd as well as FS and EF decreased
significantly (p <0.001) but Ds and Vs did not change significantly (p>
0.05). Dd and Vd did not change significantly from early to 12 months
after surgery (p> 0.05), but Ds, Vs reduced significantly from 6 months
after operation. Left ventricular systolic function improved significantly,
but the values of LV variables weren’t as high as preoperative ones.
Table 3.25: Changes of RV size and function and pulmonary pressure
in the MR group.
Variable Preop M0 M3 M6 M12
n 31 31 31 31 22
RDd (mm) 23,1 ± 6,3 21,7 ± 4,8 22,3 ± 4,0 24,4 ± 9,8 22,7 ± 5,5
TA (mm) 30,3 ± 6,7 29,3 ± 4,2 27,9 ± 3,2 27,9 ± 4,1 29,0 ± 3,3
TAPSE (mm) 20,3 ± 5,6 10,6±3,1† 12,1 ± 3,3 13,5±3,7
§
14,4±3,3*
St (cm/s) 11,8 ± 2,6 7,4 ± 1,4† 8,5 ± 1,7* 8,9 ± 1,6* 9,2 ± 1,5*
sysPAP (mmHg) 45,6 ± 16,1 33,8±6,7† 32,7 ± 7,2 33,7 ± 7,6 32,5±10,8
†- p < 0,001 compared with before operation ;

*-p< 0,05;
§
-p<0,001 compared with early after operation
13
Right ventricular dimensions did not change significantly after
surgery at 12 months after surgery (p> 0,05). RV function decreased
significantly after surgery (p <0001), and then gradually improved
but still lower than before surgery (p <0.001). Pulmonary pressure
decreased significantly after surgery from 45.6 ± 16.1 to 33.8 ± 6.7
(mmHg) (p <0.001), then the change is not significantly to 12 months
after surgery.
3.5.3. Changing the size and cardiac function in the MS/MR group
Table 3.26 showed left ventricular size and systolic function
before, early and 3, 6, 12 months after operation.
Bảng 3.26. Changes of left ventricular size and function in
MS/MR group
Variable Trước PT M0 M3 M6 M12
n 40 39 40 38 20
Dd (mm) 53,2 ± 7,2 52,8 ± 7,1 51,1 ± 5,4* 50,4 ± 5,1
§
50,2± 4,7
§
Ds(mm) 37,2 ± 6,1 37,5 ± 6,7 38,3±17,6 34,5 ± 5,1
§
34,6± 5,5
§
Vd (ml) 143,8± 40,0 137,0±37,2 126,1±31,3* 120,8±31,8
§
122,8±32,9
§

Vs(ml) 61,2 ± 23,3 62,8±32,8 52,6 ± 19,6* 49,9 ± 19,2* 51,7± 20,8*
FS (%) 31,1 ± 5,2 28,9 ± 6,1 31,9 ± 6,3* 31,5 ± 4,4* 31,7± 5,9
§
EF (%) 58,1 ± 7,7 54,8 ± 9,5 56,9 ± 9,9* 56,8 ± 8,4* 59,5± 8,1*
*-p< 0,05;
§
-p<0,001 compared with early after operation
Early after surgery, left ventricular end-systolic and end-
diastolic dimensions and LV systolic function did not change
with statistical significance (p> 0.05). At 6 and 12 months after
surgery, Dd, Ds decreased significantly (p<0.01), and left
ventricular systolic function improved significantly (FS and EF
increased with statistical significance p < 0.001 and p <0,05).
14
Table 3 .27. Changes of RV size and function and pulmonary pressure
in the MS/MR group.
Variable Preop M0 M3 M6 M12
n 40 39 40 38 20
RDd (mm) 22,8 ± 5,1 22,8 ± 3,7 23,8 ± 6,5 22,1 ± 3,4 22,3 ± 3,3
TA (mm) 31,7 ± 5,8 26,9± 4,1
†
26,8 ± 3,3 27,7 ± 5,3 28,1 ± 5,6
TAPSE (mm) 16,1 ± 5,2 9,7 ± 2,8
†
11,9±
2,7*
11,9±
2,9*
13,2± 2,9*
St (cm/s) 9,2 ± 2,2 7,2 ± 1,4

†
8,2 ± 1,6
§
8,1 ± 1,7
§
8,3 ± 2,0
§
sysPAP (mmHg) 53,9 ± 16,0 34,6± 5,9
†
32,8 ± 5,2 33,7 ± 8,6 34,4 ± 1,8
†- p < 0,001 compared with before operation;
*-p< 0,05; §-p<0,001 compared with early after operation
Right ventricular size changed without statistical significance
(p> 0.05), but right ventricular systolic function reduced (p<0.001).
Tricuspid annular diameter decreased significantly with p<0.001.
Following up to 12 months after operarion data showed no changed
with statistical significance, but right ventricular function improved
significantly from 3rd month (p <0,05).
3.5.4. Tricuspid regurgitation after surgery
After surgery, the incidence of moderate and severe TR decreased
and those of mild TR increased. But there were still 12 patients with
moderate TR (2/4) and 5 patients with severe TR (3/4). The incidences
were similar at 3 and 6 months and tended to decrease at 12 months after
surgery, but the decrease was not statistically significant (p> 0,05).
3.5.5. Comparison of postoperative left ventricular systolic
function between group with and without decreased preoperative
systolic function
Table 3.38. Comparison of postoperative EF between groups with
15
EF < 50% and EF ≥ 50%

Timing Group EF < 50% Group EF ≥ 50% p
n = 13 n = 91
Preop 46,6 ± 1,5 61,9 ± 6,6 < 0,001
M1 52,2 ± 10,5 55,9 ± 8,6 0,133
M6 53,2 ± 9,3 60,5 ± 7,8 < 0,001
M12 53,2 ± 10,4 61,7 ± 8,3 < 0,001
Left ventricular systolic function in the 2 groups were reduced
early after surgery. At 6 months and 1 year after surgery, left
ventricular systolic function had recovered, but in preoperative EF
<50% group, LV function is still worse than that in the preoperative
EF ≥ 50% group.
In the MS group, early after surgery, left ventricular systolic
function did not differ significantly (p> 0.05). However, at 6 and 12
months after surgery, patients with EF ≥ 50% had left ventricular
systolic function better with statistical significance p <0.05.
In the MR group, the patients with EF ≥ 50% had left
ventricular systolic function recovered better at 1, 6 and 12 months
after surgery, as compared with preoperative EF <50% group
(p<0,05). Group of patients with preoperative EF <50% had left
ventricular systolic function did not change at 6 months and 12
months after surgery, as compared with early postoperation (p>
0,05).
In the MS/MR group, left ventricular systolic function in
groups with preoperative EF ≥ 50% tended to be higher in the group
with EF <50%, but without statistical significance. Nevertheless, p
was lower at 12 months after operation, as compared with that at 6
months and gradually comed closer to 0.05.
16
3.5.6. Pulmonary pressure reduction in groups with and wiothout
preoperative severe pulmonary hypertension.

Table 3:42. Compare systolic PAP between groups with < 60 mmHg and
group with systolic PAP
≥
60mmHg
Timing
sys PAP < 60 mmHg Sys PAP ≥ 60 mmHg
p
n 72 31
M1 32,9 ± 6,0 37,7 ± 11,2 0,01
M6 33,1 ± 6,1 36,1 ± 8,2 <0,05
M12 32,4 ± 7,5 35,5 ± 8,9 0,121
Early after surgery, the systolic PAP in the severe PAP
hypertension group was still higher than that of the group without
severe hypertension (p <0,01). Systolic PAP in the 2 groups with
and without severe pulmonary hypertension did not differ
significantly at 12 months after surgery (p> 0.05) .
3.5.13. Thrombotic complications of prosthetic mechanical valve
There were 2 cases of mechanical obstructive thrombosis
complications in our study, accounting for 2%. 1 patient had this
complication early, during the first months after surgery (1%) and the
other at 2 years after surgery due to giving up re-examination. Both the
patients had the diagnosis suspected by TTE and determined by TEE.
3.5.14. Complications of infective endocarditis
There are 2 patients with positive blood cultures soon after
surgery but there were no abnormal images on TTE and on TEE,
possibly because these patients had early antibiotic treatment and
infection has been localized.
17
Chapter 4
DISCUSSION

4.1. General characteristics of the study group patients
The general characteristics of age, gender ratio, NYHA level,
the percentage of atrial fibrillation, chest cardiac index were similar
to other studies on mitral valve replacement surgery as Nguyen Hong
Hanh, Ho Huynh Quang Tri, Nguyen Duy Thang Dang Hanh Son
4.2.Preoperative echocardiographic Doppler characteristics
The preoperative echocardiographic data demonstrates that our
patients are operated on in the late stages of the disease. Mitral valve
diseases had affected the heart and pulmonary pressure: right and left
ventricular dilatation, severe TR and pulmonary hypertension, similar
to the studies of other authors in the country.
4.3. Surgical characteristics of the study subjects
The sizes of prothetic valves the most used were 29 and 31, similar
to the study of Nguyen Hong Hanh. There were 68/74 patients with
preoperative TR ≥ 2/4 and had tricuspid annuloplasty, in which 58
patients (56.3%) underwent modified De Vega method. This rate is
similar to D. H. Son’s research and higher than that of N. D. T.
Tricuspid valve repair resulted in significantly improved long-term
survival, event-free survival, and survival free of recurrent TR
4.4. Echocardiographic characteristics of the mitral Sorin
Bicarbon prostheses
In our study, transprosthetic peak gradient is 10.0 ± 3.0 mmHg
and mean gradient is 4.1 ± 1.3 mmHg, similar to the results of Banado.
There were no statistically significant difference (p> 0, 05)
between our results and those of N. H. H’s data on the St. Jude valve
Masters, i.e the performance of Sorin Bicarbon and St. Jude Masters
valve are similar . Camilleri had the same results.
The average value of PHT was 74.1 ± 8.1 (ms), and average
effective orifice area calculated by PHT method was 3.0 ± 0.5 cm2,
similar to the results of Banado and Reisner.

18
On transthoracic echocardiography, physiological regurgitation
is observed in 81.1% of the patients, higher than in the Banado’s
study (17%). On TEE study, 3 minimal regurgitant flows were
clearly observed in all patients (100%), and the largest flows were
often the peripheral ones. The length of the largest flow was 20.2 ±
5.2 (mm), the average width of 2.3 ± 0.5 (mm), and open flow area
average was 1.3 ± 0.5 cm
2
. This result is similar to the results of
Banado.
No severe paraprosthetic regurgitation was discovered on TTE
and TEE study. 10 patients (10.2%) had a small paraprosthetic
regurgitant flow discovered on TEE within 1 month after surgery. This
prevalance is lower than Ionescu’s data (38%), possibly because in
Ionescu's study, TEE was performed only 2 hours after surgery when
small jets between a suture and the edges of the hole produced by the
needle remained and we used interrupted sutures technique.
4.5. The changes in size and left ventricular function after surgery
For all the patients, FS and EF decreased early after surgery
due to the reduction of left ventricular end-diastolic size, while left
ventricular end-systolic size did not change sinificantly. However, at
12 months after surgery, LV end-diastolic and end-systolic size
decreased significantly (p <0.001), and left ventricular systolic
function improved with EF increased from 54.1 ± 9.5 to 60.1 ± 9.3
(%) (p <0.001). In this study, improved left ventricular systolic
function can be observed from the 3rd month.
In the MS and the MS/MR group, left ventricular size and
systolic function did not change significantly after surgery but the
function was only at the lower limit of normal. However, by 6

months after surgery, left ventricular systolic function improved
significantly, possibly due to increased left ventricular filling would
increase left ventricular muscle contraction according to Starling's
law. This result is similar to the results of Crawford.
In the MR group, LV end-diastolic size decreased significantly
after surgery (p <0.001), whereas ther were no significant change in end-
19
systolic size (p> 0,05). This leads to the significant reduction (p <0.001)
of fraction shortening (FS) and ejection fraction (EF). Follow up
revealed no significant change of LV end-diastolic size from
immediately after surgery to 12 months after surgery (p> 0.05), while
end-systolic size significantly smaller from 6 month, and LV function
improved from 3
rd
month. However, the FS and EF values were lower
than before surgery. This result is similar to the results of many foreign
published data. In our study, recovery of left ventricular systolic function
in patients with EF <50% was worse than those with preoperative EF ≥
50%, especially in predominant MR group.
4.6. Changes in pulmonary pressure
Lowering pulmonary pressure is one of the goals of the mitral
replacement surgery, in order to limit the progression of heart failure
and to severe tricuspid regurgitation. Our study shows that the
pulmonary pressure reduced markedly after replacement surgery due
to left atrial pressure reduction and decreased pulmonary
vasoconstriction. Mubeen’s study on patients with severe pulmonary
hypertension demonsrated that all patients had reduced pulmonary
pressure immediat after mitral replacement surgery. Pulmonary artery
pressure continued to decrease over the next 6 months, but the further
decrease was less than in immediate postoperative period. In our

study, at 12 months after surgery, the systolic PAP was not
significantly different between the group with and without severe
pulmonary hypertension, which suggests that mitral valve
replacement surgery can be carried out safely and effectively in
patients with severe pulmonary hypertension.
4.7. Changes in right ventricular size and function
Right ventricular function is also an important prognostic
factor in chronic heart failure and valvular heart disease. In this
study, we selected tricuspid annular plane systolic excursion
(TAPSE) and systolic tissue Doppler signal of the tricuspid annulus
(St) to assess right ventricular function because they are easy to
20
measure, reliable and reproducible and reflect the predominant RV
longitudinal contraction.
In our study, right ventricular and tricuspid annular diameters
reduced early after surgery. However, the right ventricular contractile
function also significantly reduced. After mitral replacement surgery,
reduction of pulmonary arterial pressure and the correction of tricuspid
annulus may have facilitated the right ventricle as well as decreased the
TA diameters. Right ventricular systolic function reduced after surgery
may be explained by the surgical procedure affected the right ventricle.
Experimental models have shown that 20% to 40% of RV systolic
pressure and volume outflow results from left ventricular contraction
and the reduction of left ventricular systolic function after surgery also
affects right ventricular systolic function.
Over the 12- month follow-up, right ventricular size and TA
diameter did not change significantly, but right ventricular systolic
function improved, perhaps by PAP reduction, improvement of TR
grade and left ventricular systolic function.
4.8. Changes in the prevalance of tricuspid valve regurgitation

The immediate result and 6–month outcome of tricuspid
annuloplasty in our study are good. There was a significant reduction
in tricuspid regurgitation severity: Prevalance of mild TR increased,
and those of moderate and severe TR decreased.
At our hospital, tricupide annuloplasty was performed by the
De Vega suture annuloplasty technique, using pericardial strips or
annuloplasty ring, in which, De Vega method was applied in 58/68
patients and 50/58 of these patients had improved TR. This method is
simple, cost effectiveness and a number of series have reported its
short and long-term success. However, other investigators have
reported a relatively high recurrence rate for the De Vega
21
technique, particularly in patients with severe tricuspid annular
dilation and/or pulmonary hypertension. 6 of our patients (10.3%)
still had 2+ TR after surgery. 2 other patients had recurrent severe TR
at 6 months after surgery. In our study, there was a nonsignificant
trend (p> 0.05) toward TR recurrence after De Vega's method, as
compared with ring annuloplasty. This may be due to the number of
patients having annuloplasty ring is rather low, only 6 patients. There
was no recurrent TR in patients with ring annuloplasty at the time of
6 months and 12 months after surgery, although these patients had
more severe TR and pulmonary hypertension, as compared with
patients having modified De Vega method. Many foreign published
data revealed that an annuloplasty ring confers significant
improvements over the De Vega repair in long-term survival and
event-free survival, as well as recurrence of TR, especially in patients
with severe TA and pulmonary hypertension.
4.9. Obstructive prosthetic valve thrombosis
Two of our patients had obstructive prosthetic valve
thrombosis. One had this complicatiopn within 1 month after surgery

and the other two years after operation. In both of the2 patients,
transthoracic examination suggested and TEE completed the
diagnostic.
Obstructive prosthetic valve thrombosis is diagnosed using
Doppler echocardiography. This complication is suspected if TTE
demonstrates increased transvalvular gradients, prolonged PHT and
reduced effective orifice area (EOA). TEE plays very important role
to help confirm the diagnosis, monitoring and assessment of
thrombolytic treatment. TEE allows the demonstration of limited
leaflet motion and the detection of any obstructive mass, and the
visualization of coexistent left atrial thrombi.
22
23
CONCLUSION
Through the early results and follow-up the patients
undergoing mitral valve replacement with Sorin Bicarbon
prostheses, we draw some conclusions:
1. About hemodynamics and cardiac function changes after
mitral valve replacement surgery by Sorin Bicarbon prostheses.
 Left ventricular systolic function improved at 3 months (p
<0.05) and markedly from month 6 and 12 months after mitral valve
replacement surgery (p <0.001), and pulmonary pressure also
decreased significantly after surgery (p <0.001).
 In the MS and MS/MR group, left ventricular size and
systolic function did not change with statistical significance (p> 0.05)
early after surgery, but 6-12 month postoperative left ventricular
systolic function improved (p <0,05).
 In the mitral regurgitation group, ejection fraction
decreased significantly after surgery (63.5 ± 8.3% to 49.8 ± 8.5%) (p
<0.001). From 6 months after surgery, ejection fraction improved

gradually, but still remained lower than before surgery.
 Pulmonary artery pressure decreased significantly from
51.7 ± 18.0 mmHg to 35.0 ± 17.8 mmHg (p <0.001) early after
surgery. Pulmonary pressure had further reduction during follow-up,
but the reduction is less than the early postoperative period (p <0,05).
 Improvement of the severity or TR. Prevalance of mild tricuspid
regurgitation increased, those of moderate and severe TR decreased.
 The incidence of postoperative pericardial effusion was
61.5%, most were clinically insignificant and needn’t drainage.
2. TTE and TEE assessement of Sorin Bicarbon mitral prostheses
 Leaflet movements can be observed both by transthoracic
and transesophageal echocardiography.
 Results on some parameters of the mitral Sorin Bicarbon
transprosthetic flows obtained as follows:
• Peak pressure gradient: 9.9 ± 2.7 mmHg
24
• Mean pressure gradient: 4.2 ± 1.3 mmHg.
• The pressure half time (PHT) : 74.1 ± 8.1 ms.
• Effective orifice area calculated by the continuity equation:
2.2 ± 0.6 cm2
• Effective orifice area calculated by the continuity equation
indexed : 1.5 ± 0.4 cm2/m2.
 The incidence of detection of physiologic regurgitation on
on TTE was 81.1% and TEE was 100%.
 Within 1 month after mitral valve replacement surgery by
Sorin Bicarbon valves, 10.2% of patients had small paraprosthetic
regurgitant flows on TEE.
 Prevalance of obstructive prosthetic mitral valve was 1.9%;
The diagnose is suspected and diagnosis identified by SATQTQ.
 1.9% of patients had infective endocarditis, but there

weren’t any abnomal images on TTE and TEE, maybe due to early
treatment.
PROPOSALS
With the results obtained from this study we propose following
recommendations:
 Sorin Bicarbon is one of the prosthetic valves improving
hemodynamic and left ventricular function after mitral valve
replacement, the values of Doppler echocardiographic parameters on
the transprosthetic flow are similar to other two leaflets prostheses,
so the valve can be widely used for patients when mitral valve
replacement is indicated.
 Mitral replacement surgery should be performed when
ejection fraction was ≥ 50% for better postoperative left ventricular
systolic function improvement. Further studies of improvement left
ventricular function after mitral replacement with subvalvular
preservation should be carried out, especially in patients having
reduced left ventricular systolic function.
25