Download Opening and Closing Characteristics of the Aortic Valve

Opening and Closing Characteristics of the Aortic Valve
After Different Types of Valve-Preserving Surgery
Rainer G. Leyh, MD; Claudia Schmidtke, MD;
Hans-Hinrich Sievers, PhD, FETCS; Magdi H. Yacoub, PhD, FRCS
Downloaded from http://circ.ahajournals.org/ by guest on April 30, 2017
Background—The surgical approach to aortic root aneurysm and/or dissection remains controversial. The use of
valve-sparing operations, which are thought to have many advantages, is increasing. We hypothesized that the particular
technique and type of surgery could influence valve motion characteristics and function. Therefore, we studied the
instantaneous opening and closing characteristics of the aortic valve after the main 2 types of valve-sparing surgery.
Methods and Results—In 20 patients (10 with tube replacement of the aortic root, group A; and 10 with separate
replacement of the sinuses of Valsalva, group B) and 10 controls (group C), transthoracic and transesophageal studies
on aortic valve dynamics were performed. Three distinct phases of aortic valve motion were identified. They were as
follows: (1) a rapid opening, with a velocity of 20.964.2 cm/s in group C, 27.1610.9 cm/s in group B (P5NS), and
58.3618.4 cm/s in group A (group A versus group C, P,0.001; group A versus group B, P50.001); (2) a slow systolic
closure, with 12.566.6% and 10.862.2% of maximal opening in groups C and B, respectively (P5NS), and 3.861.6%
in group A (group A versus group C, P50.001; group A versus group B, P,0.001); and (3) a rapid closing movement,
with a velocity of 26.365.6 cm/s in group C, 32.4611.4 cm/s in group B (P5NS), and 21.863.5 cm/s in group A (group
A versus group C, P5NS; group A versus group B, P50.008). The pressure strain of the elastic modulus was different
in groups C and B only at the commissures (6826145 g/cm2 versus 18966726 g/cm2, respectively; P,0.001). At all
root levels, the distensibility was reduced in group A (P,0.001). Systolic contact of aortic cusps and wall occurred only
in group A.
Conclusions—Near-normal opening and closing characteristics can be achieved by a technique that preserves the shape
and independent mobility of the sinuses of Valsalva. (Circulation. 1999;100:2153-2160.)
Key Words: aorta n valves n surgery n echocardiography
T
he surgical approach to aortic root aneurysm and/or
dissection is still controversial. Replacing the diseased
aortic root with a composite graft including a mechanical
valve is commonly performed; with this procedure, patients
must accept the disadvantages of lifelong anticoagulation and
risks of thromboembolism, hemorrhage, endocarditis, and
restricted hemodynamics in favor of defined, long-term
function of the prosthesis.1–5 Because aortic disease leaves
the aortic valve cusps largely unaffected, valve-preserving
operations, with excision of all diseased tissue, have been
developed and used in several series.6 –13 The main 2 techniques used either replace the diseased sinuses of Valsalva by
3 separate, tongue-shaped extensions of the Dacron tube, thus
maintaining the independent mobility of each sinus,6,7,13 or
suture the mobilized aortic valve inside the cylindrical Dacron tube.8 The influence of the particular technique used on
the opening and closing characteristics of the aortic valve,
including the pattern of instantaneous movements of the
cusps and aortic wall during the different parts of the cardiac
cycle, has not been studied before. These movements could
have important implications on the durability of the repair
and, possibly, on coronary flow and left ventricular function
and, thus, long-term results. The purpose of this study was to
evaluate echocardiographically the opening and closing characteristics of the aortic valve after the 2 main types of
valve-preserving surgery.
Methods
Patients
Between November 1992 and September 1997, 20 patients with
aortic root disease underwent 2 different types of aortic valvesparing operations. During the initial period, the David technique
(group A; n510) was performed8; subsequently, the Yacoub technique (group B; n510) was used.7,13 The inclusion criteria for both
groups were identical and consisted of the absence of gross organic
changes in the valve cusps, regardless of the size of the aneurysm,
the duration of aortic insufficiency, ventricular function, or age.
Patients with severe neurological abnormalities before the operation
were excluded. The control group (group C) consisted of 10 healthy
Received March 11, 1999; revision received July 16, 1999; accepted July 20, 1999.
From the Departments of Cardiac Surgery, Medical University of Lübeck, Lübeck, Germany (R.G.L., C.S., H.-H.S.), and the National Heart and Lung
Institute at the Imperial College of Science, Technology, and Medicine, London, UK (M.H.Y.).
Correspondence to Prof H.H. Sievers, Klinik für Herzchirurgie, Medizinische Universität zu Lübeck, Ratzeburger Allee 160, D-23538 Lübeck,
Germany. E-mail [email protected]
© 1999 American Heart Association, Inc.
Circulation is available at http://www.circulationaha.org
2153
2154
Circulation
November 23, 1999
TABLE 1.
Clinical and Operative Data
Group A
(n510)
Group B
(n510)
Group C
(n510)
7/3
7/3
8/2
Sex, M/F
Age, y
48617
58613
41614*
1.9260.15
1.8960.23
1.8260.21
Acute dissection, n
6
3
Chronic aneurysm, n
3
7
BSA, m2
Marfan syndrome, n
1
0
Follow-up, mo
23.268.5
4.161.8†
Bypass time, min
195628
192628
Ischemic time, min
143612
134617
Diameter of Dacron
prostheses
28 mm: n54
30 mm: n56
28 mm: n53
30 mm: n57
BSA indicates body surface area.
*P50.012, group C vs group B; †P,0.001, group A vs group B.
Downloaded from http://circ.ahajournals.org/ by guest on April 30, 2017
individuals in whom no abnormalities of the aortic valve, aortic root,
or left ventricle were detected by medical history, standard clinical
examination, and transesophageal echocardiography. The clinical
characteristics of all groups are shown in Table 1. Informed written
consent was obtained before echocardiography. The investigative
procedures were performed in accordance with institutional guidelines. All patients were clinically evaluated at regular intervals at
our hospital.
Operative Technique
Standard cardiopulmonary bypass with a membrane oxygenator
(Hollow Fiber Oxygenator, Spiral Gold) at moderate hypothermia
(28°C nasopharyngeal temperature) or deep hypothermic circulatory
arrest (18°C nasopharyngeal temperature) was used, and cold crystalloid cardioplegia (St. Thomas’ Hospital solution) was used for
myocardial protection. The operative techniques are described in
detail elsewhere.7,8,11,12 In brief, the David technique is performed as
follows: after excision of the sinuses, the aortic valve is implanted
inside a straight (not tailored) Dacron tube (Hemashield Gold,
Meadox Medicals) in a manner similar to the implantation of an
aortic valve homograft; this is followed by reimplantation of the
coronary ostia (Figure 1). The Yacoub technique, in brief, is as
follows: after excision of the diseased sinuses, the end of the sized
Dacron tube is trimmed to produce 3 separate, tongue-shaped
extensions, which are fixed to the aortic annulus at the line of
attachment of the cusps; this is followed by reimplantation of the
coronary ostia (Figure 1). No reduction annuloplasties were performed, except for 1 in a patient with Marfan syndrome who needed
plication of the intervalvular trigone between the noncoronary and
left coronary sinus.
Echocardiographic Data Acquisition
and Measurements
Echocardiograms were performed on a Hewlett Packard Sonos 2500
system with 2.5- and 5.0-MHz ultrasound transducers during routine
follow-up investigations. All patients underwent transthoracic and
transesophageal echocardiography at rest. Examinations were performed with the patients in the left lateral decubitus position. A
modified ECG lead I was continuously recorded. Blood pressure was
measured by cuff sphygmomanometry (Dinamap, Siemens). Echocardiographic measurements were performed while blood pressure
was constant.
Root dimensions and valve-motion parameters were determined
by 2 independent observers from video-recorded studies, and the
average value of 5 consecutive beats in sinus rhythm was taken.
To evaluate the reproducibility of the echocardiographically determined aortic root diameters at base, sinus, and commissural levels,
3 patients were studied twice using transesophageal echocardiography within a period of 10 days. The range of variation of the
sequentially measured diameters was 0% to 2.9%.
Two-Dimensional Echocardiography
First, the morphology of all 3 aortic cusps was examined in standard
longitudinal and cross-sectional views. Then, the diameters of the
aortic root at the level of the annulus, the sinuses of Valsalva, and the
commissures were determined transesophageally by using the leading edge method, as described by Roman et al.15
By definition, the annulus level was circumscribed by the nadir
hinge points of the aortic cusps, the sinus level was the largest root
diameter between the annulus and the supraaortic ridge, and the
commissural diameter was measured at the distal rim of the sinuses
of Valsalva.
Measurements of diameters were made perpendicular to the long
axis of the aorta in views showing the largest and smallest dimensions during 1 cardiac cycle. Left ventricular end-systolic and
end-diastolic volumes were obtained from standard apical 4-chamber
views. Diastole was defined as the beginning of the QRS complex on
the simultaneous ECG recording. Left ventricular outflow tract
diameter was obtained by freeze frame at maximum aortic valve
leaflet opening in systole.
M-Mode Echocardiography
Tracings were recorded from transesophageal views at 100 mm/s
paper speed on a strip chart and magnified. The purpose of these
recordings was to analyze the intermittent systolic contact of an
aortic cusp and the aortic wall, as well as the opening and closing
movements of the aortic leaflets, as defined in Figure 2. Only views
with the leaflet coaptation at the midline of the aortic root and a
symmetrical configuration of the echocardiographic appearance of
the valve motion pattern were analyzed.
Continuous-Wave and Pulsed-Wave Doppler
Figure 1. Illustration of 2 different valve-sparing techniques
used, which were modified from David et al8 and Shabbeer et
al.14 A, Technique according to David et al.8 The mobilized aortic valve is sutured inside a cylindrical Dacron tube. B, Technique according to Yacoub et al.7 The diseased sinuses are
replaced by 3 separate, tongue-shaped extensions of Dacron
tube.
Maximum velocities across the aortic valve were obtained by
continuous-wave Doppler using the apical 5-chamber view showing
the aorta and left ventricular outflow tract. With pulsed-wave
Doppler, the sample volume was placed just below the aortic leaflets
and recorded at 0.5-cm intervals to the midventricular level, where
the drop-off of aortic velocities occurred, to measure velocities and
velocity time integrals in the left ventricular outflow tract. Pulsedwave Doppler was also used for mapping the left ventricular outflow
tract to assess aortic regurgitation.
Leyh et al
Aortic Valve Motion After Valve-Preserving Surgery
2155
TABLE 2. Heart Rate, Cardiac Output, Blood Pressure, and
Valve Function
Figure 2. Schematic drawing of measured aortic valve opening
and closing characteristics of 3 distinct phases: a-b, rapid valve
opening; b-c, slow systolic closure; and c-d, rapid valve closing
movement. RVOT indicates rapid valve opening time; D1, maximal leaflet displacement; RVCT, rapid valve closing time; ET,
ejection time; SCD, slow closing displacement; and D2, leaflet
displacement before rapid valve closing.
Downloaded from http://circ.ahajournals.org/ by guest on April 30, 2017
Resting coronary artery blood flow velocity was determined by
pulsed-wave Doppler exploration of the anterior descending coronary artery.16 The resting systolic and diastolic coronary flow
velocity time integrals, defined as the area under the curve during
systole and diastole, were measured. The ratio of resting systolic to
diastolic velocity time integrals was then calculated.
Color-Flow Doppler
Aortic regurgitation was assessed by color-flow Doppler techniques
in the standard transthoracic and transesophageal views and graded
as follows using the ratio of jet height/left ventricular outflow tract
height17: ratio of 1% to 24%, Grade I; 25% to 46%, Grade II; 47%
to 64%, Grade III; and $65%, Grade IV.
Group A
(n510)
Group B
(n510)
Group C
(n510)
HR, min21
73.8611.7
80.6616.4
70.7612.2
SV, mL
84.5611.2
85.8612.4
89.3614.7
CO, L/min
6.261.0
6.461.0
6.261.1
LV-EF, %
60.466.9
61.367.6
64.266.3
SBP, mm Hg
120610
126611
120612
DBP, mm Hg
7867
8167
77611
PG, mm Hg
RG grade
5.461.4
3.862.0
4.361.6
grade 0: n55*
grade 0: n57†
grade 0: n510
grade I: n55
grade I: n53
HR indicates heart rate; SV, stroke volume; CO, cardiac output; LV-EF, left
ventricular ejection fraction; SBP, systolic blood pressure; DBP, diastolic blood
pressure; PG, maximum pressure gradient; and RG, regurgitation.
*P50.039, group A vs group C; †P50.039, group B vs group C.
Pressure strain elastic modulus (PSEM) was calculated as follows:
PSEM5~DP3R!/DR
where DP is the difference between systolic and diastolic blood
pressures.18
Slow closing displacement (SCD) of leaflets was calculated using
the following:
SCD5
D1 2D2
3100
D2
where D1 indicates the maximal leaflet displacement, and D2, leaflet
displacement before rapid valve closing (Figure 2).
Statistical Analysis
Calculations
The following items were calculated with the indicated formulas.
Cardiac output (CO) was calculated using:
CO5HR3SV
where HR indicates heart rate, and SV, stroke volume, which was
calculated as follows:
SV5VTI3~D/ 2! 23p
where VTI indicates velocity time integral in the left ventricular
outflow tract, and D, the diameter of the left ventricular outflow
tract.
Ejection fraction (EF) was calculated as follows:
EF5
EDV2ESV
3100
EDV
where EDV and ESV indicate the end-diastolic and end-systolic
volumes of the left ventricle, calculated according to the modified
Simpson’s rule.
Peak systolic pressure gradient across the aortic valve (Dp) was
calculated as follows:
Dp54V 2
where V indicates the peak systolic velocity across the aortic valve.
Percent change in radius (PCR) was calculated using the
following:
PCR5~DR3100!/R
where DR indicates the difference between the largest and smallest
diameter, and R, the average diameter.18
Data are given as mean6SD. To compare the continuous data of
different groups, the H test according to Kruskal-Wallis was used. If
significantly different, a Mann-Whitney ranked sum test (U-test) was
applied. According to Bonferroni’s method for multiple pairwise
tests, a 2-tailed P#0.016 (0.05/3) was considered significant. Relative frequencies were analyzed using the x2 test. Statistics were
performed using statistical software (SPSS for Windows 6.0, SPSS
Inc).
Results
No early or late deaths occurred in this series during the
follow-up period of 2 to 42 months (mean, 13.7611.6
months). No endocarditis or thromboembolic events occurred. No patient was on oral anticoagulants or antiplatelets.
All patients were in New York Heart Association Class I at
the latest follow-up. Clinically, all patients were judged to
have good valve function throughout the follow-up period.
Heart rate, stroke volume, cardiac output, ejection fraction,
blood pressure, and the transvalvular aortic pressure gradient
were comparable in the 3 groups (Table 2).
A total of 50% of patients in group A (David procedure)
and 70% of patients in group B (Yacoub procedure) had no
aortic regurgitation. None of the patients had more than grade
I aortic regurgitation. No calcifications, vegetation, or areas
of thickening were observed on any leaflet.
Valve Opening and Closing Characteristics
Three distinct phases of aortic valve movement were observed: a rapid valve opening, a slow systolic closure, and a
2156
Circulation
November 23, 1999
distensibility in group A was significantly reduced; it did not
exceed a 2.2% change in radius with a high pressure strain
elastic modulus of .1900 g/cm2 at any measured level. In
contrast, near-normal values for percent change in radius at
the sinus and annulus level of 9.6% and 10.1% were observed
for group B; at the commissural level, the root was relatively
stiff, with only a 2.7% change in radius and a pressure strain
elastic modulus, on average, of 18966726 g/cm2.
Figure 3. Diagram of 3 distinct phases of aortic valve motion
pattern derived from mean values of measured data. Note faster
opening and reduced slow systolic closure in group A.
Downloaded from http://circ.ahajournals.org/ by guest on April 30, 2017
rapid valve closing movement (Figures 2 and 3 and Table 3).
Valve opening and closing characteristics were largely similar in groups B and C (Figure 3, Table 3). The rapid opening
of the valve in these groups was smooth, with a similar
average speed of 27.1 cm/s in group B and 20.9 cm/s in
controls. Maximal opening of the valve was achieved 14.5 ms
later, on average, in controls compared with group B patients.
Valve displacement was 21.1 mm smaller in group B than in
group C (23.1 mm).
In contrast, the valves in group A opened faster, with an
essentially increased speed of 58.3 cm/s and a shorter time
(23.0 ms) for maximal opening. Valve displacement (Table 3)
was largest (26.0 mm) in this group of patients.
The duration of valve opening as expressed as ejection
time was shortest in group B. The decrease of valve displacement during the slow closing movement (Table 3, Figure 3)
was less apparent in group A (only 3.8% of maximal opening)
than in groups B and C (.10% for both). The valves in group
A took longer for rapid closing (Table 3, Figure 3), with a
decreased speed (21.8 cm/s) when compared with groups B
and C (32.4 and 26.3 cm/s, respectively).
Intermittent systolic contact of $1 aortic cusp with the
aortic wall was a constant finding in all patients in group A
but no patients in groups B and C (Figure 4).
Aortic Root Distensibility
Cyclic changes in the radius and pressure strain elastic
modulus, as parameters of the distensibility of the aortic root,
are listed in Table 4 and illustrated in Figure 5. Aortic root
TABLE 3.
Coronary Artery Blood Flow Velocity
A biphasic pattern of coronary blood flow velocity in the left
anterior descending coronary artery at rest with a greater
diastolic component (9.02 cm in group B, 8.63 cm in group
A, and 9.98 cm in group C) and a smaller systolic component
(3.1 cm in group A, 3.48 cm in group B, and 3.98 cm in group
C) was recorded (Table 5). No significant differences in
coronary artery flow velocity were observed in the 3 groups.
Discussion
This study defines, for the first time, the pattern of instantaneous valve opening and closing after valve-sparing operations compared with normal subjects. In addition, we showed
that valve opening and closing characteristics varied with the
particular technique used. These findings could have implications on the durability of the repair and, possibly, on
cardiac performance.
The concept of valve repair is extremely appealing in
patients with aortic root malformation in whom the disease
process is largely confined to the aortic wall, leaving the
aortic cusps capable of functioning normally for varying
periods of time, despite the presence of histological abnormalities, particularly in Marfan syndrome.19
The success of this operation depends on preserving the
extremely sophisticated dynamic function of the valve, which
is best suited for its hemodynamic performance to maintain
optimal left ventricular function, coronary blood flow, and
cardiac output under widely different physiological and
pathological conditions while minimizing mechanical stress
on the leaflets.
Previous studies in animal models using high-speed cineradiography20 or electromagnetic induction techniques21 have
shown changes in root dimension during the cardiac cycle
Valve Opening and Closing Characteristics
P
Group A
(n510)
Group B
(n510)
Group C
(n510)
A vs C
B vs C
A vs B
RVOT, ms
23.069.5
43.0611.6
57.5611.1
,0.001
0.018
0.003
D1, mm
26.063.4
21.163.5
23.161.3
0.019
NS
0.006
RVOV, cm/s
58.3618
27.1610.9
20.964.2
,0.001
NS
0.001
ET, ms
319648
254654
329663
NS
0.011
0.011
3.861.6
10.862.2
12.566.6
0.001
NS
,0.001
RVCT, ms
58.5610
31.568.8
39.565
0.001
0.014
,0.001
D2, mm
25.063.5
18.962.9
20.562.4
0.006
NS
0.002
RVCV, cm/s
21.863.5
32.4611.4
26.365.6
NS
NS
0.008
SCD, %
RVOT indicates rapid valve opening time; D1, maximal leaflet displacement; RVOV, rapid valve opening velocity; ET,
ejection time; SCD, slow closing displacement; RVCT, rapid valve closing time; D2, leaflet displacement before rapid
valve closing; RVCV, rapid valve closing velocity; and NS, not significant.
Leyh et al
Aortic Valve Motion After Valve-Preserving Surgery
2157
Downloaded from http://circ.ahajournals.org/ by guest on April 30, 2017
Figure 4. Echocardiographic picture of systolic contact (arrow) of 1 aortic cusp and aortic wall in group A.
that are thought to be important for the smooth functioning of
the aortic valve. These changes have 3 distinct phases: a rapid
valve opening, a slow systolic closure, and a rapid valve
closing movement.
Using transesophageal echocardiography in control subjects, we found a pattern of movement of the cusps and the
aortic root similar to that observed by Thubrikar et al20,22 and
Higashidate et al21 in animal models.
After root replacement with separate reconstruction of the
sinuses (group B), we measured an opening velocity of
27.1610.9 cm/s, which was similar to that of the controls
(group C; 20.9642 cm/s). The aortic root distensibility in
group B was also comparable to controls, except for a
distensibility of a 2.7% change in radius at the upper part of
TABLE 4.
the sinuses. This restricted distensibility, however, did not
affect valve opening and closing characteristics, which were
largely normal in this group of patients. In contrast, the
distensibility of the aortic root was reduced in group A, with
a maximal change in the radius of 2.2% at all levels; in this
group, the velocity of valve opening was significantly faster
(57.3 cm/s). This might be explained by the fact that the aortic
root cannot change its shape during the cardiac cycle, as was
suggested by the work of Higashidate et al,21 Thubrikar et
al,20,22 and Sievers et al.23 These authors observed that the
semilunar valves start to open, without any forward flow,
only because of root expansion during the beginning of
systole in animal models. This interaction between the root
and the leaflets leads to a stellate orifice of the valve that
Aortic Root Distensibility
P
Group A
(n510)
Group B
(n510)
Group C
(n510)
A vs C
B vs C
A vs B
PCR annulus, %
2.260.5
10.163.4
9.661.5
,0.001
NS
,0.001
PCR sinus, %
1.760.4
9.662.5
10.363.4
,0.001
NS
,0.001
PCR commissures, %
2.260.5
2.760.9
7.061.8
,0.001
,0.001
NS
PSEM annulus, g/cm2
19786610
4836156
465675
,0.001
NS
,0.001
PSEM sinus, g/cm2
277061381
5026173
4676157
,0.001
NS
,0.001
PSEM commissures, g/cm2
19586493
18966726
6826145
,0.001
,0.001
NS
PCR indicates percent change in radius; PSEM, pressure strain elastic modulus; and NS, not significant.
2158
Circulation
November 23, 1999
Figure 5. Diagram of cyclic changes in dimensions derived from
mean values of measured data at base, sinus, and commissural
levels. Note reduced distensibility in group A at all levels of aortic root.
Downloaded from http://circ.ahajournals.org/ by guest on April 30, 2017
becomes circular with increasing blood flow velocity.22 Thus,
a gradual, smooth opening movement of the valve is
achieved, which reduces stresses on the leaflets.24,25
Also, left ventricular ejection parameters might have influenced valve-opening velocities.21 In our series, the ejection
time was lower in group B compared to group A and group C.
In conjunction with an equal stroke volume, this would lead
to more abrupt changes in the valve-opening motion, which is
contrary to what we observed. This emphasizes the importance of repair techniques on cusp movement. Furthermore,
we observed contact of the leaflets with the aortic wall only
in group A patients. This could be due to the rapid leaflet
displacement during opening or due to the lack of sinuses in
group A; this is supported by the echocardiographic appearance of 3 separate sinuses in controls and in patients in group
B (Figure 6). In this context, Bellhouse et al.26 reported that
the fully opened cusps are normally accurately positioned
between the sinus wall and the bloodstream, with the sinus
vortex adjusting the sinus pressure to balance that on the
aortic side of the cusps. The lack of sinuses in group A
probably prevents this mechanism from operating and, consequently, contributes to leaflet contact. Another reason for
this phenomenon could be the lack of space in the Dacron
tube, leading to a redundancy of cusp tissue.
Bellhouse and Bellhouse27 reported, in an in-vitro study,
that a valve in a straight tube without the closing forces of the
sinus vortices would increase regurgitation considerably during closure. We were, however, not able to confirm these
results; only grade I regurgitation, without significant differences between groups A and B, occurred.
In the second phase of valve movement, the degree of slow
closing motion was 10.862.2% of maximal opening in group
B, which is comparable to that of controls (12.566.6%). In
TABLE 5.
Doppler-Derived Indexes of Coronary Flow Velocity
Group A
(n56)
Group B
(n58)
Group C
(n58)
VTIs, cm
3.160.62
3.4861.11
3.9861.25
VTId, cm
8.6360.99
9.0261.1
9.9862.03
S/D ratio
0.3760.12
0.3860.1
0.4260.14
VTIs indicates resting systolic velocity time integral; VTId, resting diastolic
velocity time integral; and S/D ratio, ratio of resting systolic to diastolic time
integrals.
group A, we measured a slow closing motion of only
3.861.6%. Again, the missing sinus vortices impair the
ability of leaflets to begin to close before the onset of flow
deceleration in these patients.27 Furthermore, the lack of
internal forces, which are stored by the displacement of the
cusps after root distension and which initiate valve closure
during flow deceleration (as described for normal valves by
Thubrikar et al20 ), could have contributed to the reduced slow
systolic valve closure with reduced root distensibility in
group A.
During the third phase of valve movement, we observed
differences in the valve closing velocity between groups A
(21.863.5 cm/s) and B (32.4611.4 cm/s), although both
values are not different from that of controls (26.365.6 cm/s).
This rapid valve closure is determined by the radial thrust of
the sinus vortices on the sinus surface of the leaflets during
the deceleration phase of aortic blood flow,27 and it is then
completed by the reversal of aortic flow. The lower speed for
this movement in group A patients is probably also related to
the lack of sinus configuration and, thus, the closing forces of
sinus vortices to push the leaflets to the midline.
In addition, Bellhouse et al26 reported that sinus vortices
not only initiate valve closure but also promote coronary
artery blood flow. In our series, differences between groups
in coronary artery blood flow at rest could not be detected
during systole or diastole. Whether this holds true for exercise
conditions remains to be established.
Limitations
This study has several limitations. (1) It could be argued that
the resolution of the ultrasound technique is not sufficient to
define accurate instantaneous movements of the aortic root
and the leaflets. However, possibly more accurate techniques,
such as high speed cineradiography20 or electromagnetic
induction,21 are not applicable to humans and could interfere
with valve movement. The ultrasound technique used in this
study operates at a 900-Hz sampling frequency, providing an
interval between 2 consecutive signals of 1.1 ms, which we
believe is adequate to define aortic root motion. In addition,
the technique produced reproducible results. (2) The fact that
the aortic root moves during measurement could induce
errors. However, these errors would apply to all groups and,
therefore, should not affect comparative results. (3) Another
limitation relates to the significantly longer period of
follow-up in group A than in group B (23.268.5 versus
4.161.8 months) and the fact that this was not a randomized
study. However, the 2 groups were well matched with regard
to patient demographics and the size of the Dacron tube used.
In conclusion, we demonstrated important differences in
valve opening and closing characteristics after valve-sparing
operations, depending on the particular technique used. The
near-normal pattern of valve movement and the preserved
distensibility after the Yacoub technique could reduce stress
on the valve. This is supported by the study of Reis et al,28
who showed that increased flexibility of a stented semilunar
valve results in marked reduction of the measured stress on
the cusps. Whether the observed differences in valve movement and distensibility between the 2 groups will affect
Leyh et al
Aortic Valve Motion After Valve-Preserving Surgery
2159
Downloaded from http://circ.ahajournals.org/ by guest on April 30, 2017
Figure 6. Echocardiographic appearance of
cross-section through aortic root at sinus level.
A, group A; B, group B; and C, group C. Note
near-normal shape of sinuses of Valsalva in
group B in comparison with group A.
2160
Circulation
November 23, 1999
long-term valve durability, cardiac performance, and patient
survival remains to be evaluated.
Acknowledgment
We thank Bettina Hansen for her assistance in the preparation of
the manuscript.
References
Downloaded from http://circ.ahajournals.org/ by guest on April 30, 2017
1. Bentall HH, de Bono A. A technique for complete replacement of the
ascending aorta. Thorax. 1968;23:338 –339.
2. Crawford ES, Kirklin JW, Naftel DC, Svensson LG, Coselli JS, Safi
HJ. Surgery for acute dissection of ascending aorta. J Thorac Cardiovasc
Surg. 1992;104:46 –59.
3. Kouchoukos NT, Wareing TH, Murphy SF, Perillo JB. Sixteen-year
experience with aortic root replacement: results of 172 operations. Ann
Surg. 1991;214:308 –320.
4. Gott VL, Laschinger JC, Cameron DE, Dietz HC, Greene PS, Gillinov
AM, Pyeritz RE, Alejo DE, Fleischer KJ, Anhalt GJ, Stone CD,
McKusick VA. Marfan syndrome and the cardiovascular surgeon. Eur
J Cardiothorac Surg. 1996;10:149 –158.
5. Cabrol C, Pavie A, Mesnildrey P, Gandjbakhch I, Laughlin L, Bors V,
Corcos T. Long term results with total replacement of the ascending aorta
with reimplantation of the coronary arteries. J Thorac Cardiovasc Surg.
1986;91:17–25.
6. Fagan A, Pillai R, Radley-Smith R, Yacoub MH. Results of new valve
conserving operation for treatment of aneurysms or acute dissection of
aortic root. Br Heart J. 1983;49:302. Abstract.
7. Yacoub MH, Fagan A, Stassano, Radley-Smith R. Results of valve
conserving operations for aortic regurgitation. Circulation. 1983;68:
III-321. Abstract.
8. David TE, Feindel M. An aortic valve-sparing operation for patients with
aortic incompetence and aneurysm of the ascending aorta. J Thorac
Cardiovasc Surg. 1992;103:617– 622.
9. Simon P, Moritz A, Moidl R, Kupilik N, Grabenwoeger M, Erlich M,
Havel M. Aortic valve resuspension in ascending aortic aneurysm repair
with aortic insufficiency. Ann Thorac Surg. 1995;60:176 –180.
10. Schäfers HJ, Borst HG. Valve sparing operation in aortic root ectasia. In:
Cox JL, Sundt TM, eds. Operative Techniques in Cardiac and Thoracic
Surgery. A Comparative Atlas. Philadelphia: Saunders; 1996:38 – 43.
11. Yacoub MH, Sundt TM, Rasmi N. Management of aortic valve incompetence in patients with Marfan syndrome. In: Hetzer R, Gehle P, Ennker
J, eds. Cardiovascular Aspects of Marfan Syndrome. Darmstadt,
Germany: Steinkopf Darmstadt; 1995:71– 81.
12. Yacoub MH. Valve-conserving operation for aortic root aneurysm or dissection.
In Cox JL, Sundt TM, eds. Operative Techniques in Cardiac and Thoracic
Surgery. A Comparative Atlas. Philadelphia: Saunders; 1996:57–67.
13. Yacoub MH, Gehle P, Chandrasekaran V, Birks EJ, Child A,
Radley-Smith R. Late results of a valve preserving operation in patients
with aneurysms of the ascending aorta and root. J Thorac Cardiovasc
Surg. 1998;115:1080 –1090.
14. Shabbeer J, Child A, Yacoub M. Molecular and surgical aspects of
Marfan syndrome. In: Yacoub M, Pepper JR, eds. Annual of Cardiac
Surgery. 8th ed. Glasgow, UK: Current Science; 1995:56 – 61.
15. Roman MJ, Devereux RB, Kramer-Fox R, O’Loughlin J. Two dimensional echocardiographic aortic root dimensions in normal children and
adults. Am J Cardiol. 1989;64:507–512.
16. Memmola C, Iliceto S, Carella L, Napoli VF, de Martino G, Marangelli
V, Rizzin P. Transesophageal Doppler evaluation of coronary blood flow:
velocity in hypertrophic obstructive cardiomyopathy. J Am Coll Cardiol.
1992;19(Suppl A):323A. Abstract.
17. Perry GJ, Helmcke F, Nanda NC, Byard C, Soto BL. Evaluation of aortic
insufficiency by Doppler color flow mapping. J Am Coll Cardiol. 1987;
9:4:952–959.
18. Jarmakani JMM, Graham TP, Benson DW, Canent RV, Greenfield JC. In
vivo pressure-radius relationships of the pulmonary artery in children
with congenital heart disease. Circulation. 1971;43:585–592.
19. Fleischer KJ, Nousari HC, Anhalt GJ, Stone CD, Laschinger JC. Immunohistochemical abnormalities of fibrillin in cardiovascular tissues in
Marfan’s syndrome. Ann Thorac Surg. 1997;63:1012–1017.
20. Thubrikar MJ, Heckman JL, Nolan SP. High speed cine-radiographic
study of aortic valve leaflet motion. J Heart Valve Dis. 1993;26:653– 661.
21. Higashidate M, Tamiya K, Beppu T, Imai Y. Regulation of the aortic
valve opening. J Thorac Cardiovasc Surg. 1995;110:496 –503.
22. Thubrikar M, Bosher LP, Nolan SP. The mechanism of opening of the
aortic valve. J Thorac Cardiovasc Surg. 1979;40:863– 870.
23. Sievers HH, Storde U, Rohwedder EB, Lange PE, Onnasch DGW,
Heintzen PH, Bernhard A. Superior function of a bicuspid over a monocuspid patch for reconstruction of a hypoplastic pulmonary root in pigs.
J Thorac Cardiovasc Surg. 1993;105:4:580 –590.
24. Thubrikar M, Skinner JR, Aouad J, Finkelmeier BA, Nolan SP. Analysis
of the design and dynamics of aortic bioprostheses in vivo. J Thorac
Cardiovasc Surg. 1982;84:282–290.
25. Thubrikar MJ, Nolan SP, Aoud J, Deck JD. Stress sharing between the
sinus and leaflets of canine aortic valves. Ann Thorac Surg. 1986;42:
434 – 440.
26. Bellhouse BJ, Bellhouse FH, Reid KG. Fluid mechanics of the aortic root
with application to coronary flow. Nature. 1968;219:1059 –1061.
27. Bellhouse BJ, Bellhouse FH. Mechanism of closure of the aortic valve.
Nature. 1968;217:86 – 87.
28. Reis RL, Hancock WD, Yarbrough JW, Glancy DL, Morrow AG. The
flexible stent: a new concept in the fabrication of tissue heart valve
prostheses. J Thorac Cardiovasc Surg. 1971;62:683– 689.
Opening and Closing Characteristics of the Aortic Valve After Different Types of
Valve-Preserving Surgery
Rainer G. Leyh, Claudia Schmidtke, Hans-Hinrich Sievers and Magdi H. Yacoub
Downloaded from http://circ.ahajournals.org/ by guest on April 30, 2017
Circulation. 1999;100:2153-2160
doi: 10.1161/01.CIR.100.21.2153
Circulation is published by the American Heart Association, 7272 Greenville Avenue, Dallas, TX 75231
Copyright © 1999 American Heart Association, Inc. All rights reserved.
Print ISSN: 0009-7322. Online ISSN: 1524-4539
The online version of this article, along with updated information and services, is located on the
World Wide Web at:
http://circ.ahajournals.org/content/100/21/2153
Permissions: Requests for permissions to reproduce figures, tables, or portions of articles originally published
in Circulation can be obtained via RightsLink, a service of the Copyright Clearance Center, not the Editorial
Office. Once the online version of the published article for which permission is being requested is located,
click Request Permissions in the middle column of the Web page under Services. Further information about
this process is available in the Permissions and Rights Question and Answer document.
Reprints: Information about reprints can be found online at:
http://www.lww.com/reprints
Subscriptions: Information about subscribing to Circulation is online at:
http://circ.ahajournals.org//subscriptions/