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

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

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

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.

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

(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

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

†
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 ;

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).
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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

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.
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3.5.6. Pulmonary pressure reduction in groups with and wiothout
preoperative severe pulmonary hypertension.

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.

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

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

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