INTRODUCTION
Among open intra-cardiac procedures, Aortic valve repair was one
of the first (McMullan et al., 2007; Ruzmetov et al., 2006).
However, the availability of safe valve prostheses led cardiac surgeons
to abandon the use of aortic valve repair. More recently, greater awareness
of the long-term complications associated with currently available prostheses
and the standardization and acceptance of repair techniques for atrio-ventricular
valves, have renewed interest in aortic valve repair. Bicuspid aortic
valves permitting aortic insufficiency are the lesions most amenable to
this intervention (Spataro et al., 2008).
Although several institutions have reported their experience with aortic
valve repair (Casselman et al., 1999; Fraser and Cosgrove, 2001).
This procedure remains controversial. The present study describes our
techniques for repairing congenital bicuspid aortic valve and reports
early and midterm results.
MATERIALS AND METHODS
Patients: Between August 1997 and December 2000, 19 consecutive
patients with Aortic Regurgitation (AR) due to congenital bicuspid aortic
valve underwent surgery at Shariati Hospital. Eighty-nine percent were
male. Patients` ages ranged from 16 to 70 years (mean age, 42 ± 17
years). Preoperatively, 6 patients were assigned to New York Heart Association
(NYHA) class I, 8 to class II and 5 to class III. All patients had a pre
and postoperative 2-D (B and M-mode) echocardiography to determine left
ventricular function, as reflected by the left ventricular end-diastolic
(LVEDD) and end-systolic diameter (LVESD) and the left ventricular fractional
shortening (%FS). Using continuous wave and pulsed Doppler signals, we
assessed maximum velocity across the valve and the presence of residual
regurgitation. The presence of residual AR was graded from 1 to 4 on the
basis of the ratio of jet height/left ventricular outflow tract height
(Perry et al., 1998). AR was graded as 1+ in 1 patient, 2+ in 2
patients, 3+ in 11 patients and 4+ in 5 patients. Fourteen patients had
pure AR. Two patients had active infectious endocarditis, 1 of whom also
had mitral valve regurgitation (MR). The other patient had a Ventricular
Septal Defect (VSD) and tricuspid valve regurgitation (TR). One patient
had angina pectoris and 2 had an ascending aortic aneurysm.
Mid-term follow-up data was obtained by postal questionnaires sent to
referring physicians between July and August 2000. And then, a transthoracic
echocardiography was performed in our hospital. Information was collected
on the patients` current status, medication, morbidity and mortality by
questionnaire.
Surgical procedure: After standard median sternotomy, cardiopulmonary
bypass (CPB) was established. A left ventricular vent and moderate systemic
hypothermia were used in all patients. After aortic cross-clamping, a
transverse aortotomy was performed and cold cardioplegic solution was
infused directly into the coronary ostia.
Following valve repair and resuscitation of the heart, the patient was
weaned from CPB. At this time, the repaired valve was evaluated by transesophageal
ech-ocardiography (TEE). We did not accept an intraoperative result worse
than grade +2 AR. When necessary, the heart was rearrested and aortic
valve replacement or repair was performed.
Operative technique: The details of our technique for aortic valve
repair have been described elsewhere (Kawazoe, 1997; Izumoto et al.,
1995; Kawazoe et al., 2001). Basically, following resection of
the raphe, any redundant or prolapsing cusp is repaired by a few interrupted
stitches placed in the middle of the prolapsing leaflet; the leaflet itself
is not resected. A subcommissural annuloplasty is performed. The reinforced
annuloplasty technique was used in 2 patients, employing an approximately
2 mm-wide Gore-Tex strip (WL Gore and Associates, Flagstaff, AZ).
Concomitant procedures included mitral valve replacement in 1 patient,
VSD patch closure and tricuspid valve annuloplasty in another patient,
patch angioplasty of the left main trunk in 1 patient and replacement
of the ascending aorta in 2 patients. Operative techniques for aortic
valve repair and concomitant procedure are shown in Table
1.
Concomitant procedures: mitral valve replacement (n = 1), patch angioplasty
of left main trunk (n = 1), ventricular septal defect patch closure +
tricuspid valve annuloplasty (n = 1), replacement of the ascending aorta
(n = 2).
| Table 1: |
Operative techniques for aortic valve repair and concomitant
procedures |
 |
Statistical analysis: All data are expressed as the mean ± Standard
Deviation. For statistical analysis, the unpaired Student`s F-test was
used. Results were considered significant at p<0.05. Survival curve
and freedom from reoperation were calculated using the method of Kaplan-Meier.
RESULTS
No patients required valve replacement, but 2 patients developed
aortic stenosis. The left ventricular-aortic mean pressure gradients (mPG)
were 48 and 60 mmHg intraoperatively. One hospital death occurred due
to superior mesenteric artery thrombosis (5-2%). In this series, the mean
CPB time was 134 ± 50 min and the mean aortic cross-clamp time was
94 ± 43 min.
Short-term assessment: One patient required AVR 25 days following
the initial procedure due to a recurrence of infective endocarditis. Based
on echocardiography performed just prior to hospital discharge, AR was
graded as 0 in 6 patients, 1+ in 7 patients, 2+ in 3 patients and 3+ in
one patient. Two patients who were diagnosed with aortic stenosis intraoperatively
had mPGs of 19 and 13 mmHg. Postoperatively 17 patients have NYHA class
1 and 1 was class 2 (p<0.05). The LVEDD decreased from 67 ±
12 to 58 ± 8 mm, the LVESD decreased from 43 ± 10 to 40+7
mm. The echocardiographic ejection fraction changed from 59 ± 12
to 55 ± 9 and fractional shortening decreased from 37 ±
7 to 30 ± 4 (Table 2).
Midterm assessment: Mean duration of follow-up was 40 ± 23
months (range 0.5 to 84 months) and available for all patients.
Two patients underwent aortic valve re-operation at 24 and 50 months
following the initial procedure. One re-operation was due to dehiscence
of the subcommissural annuloplasty and the other was the result of leaflet
suture dehiscence. Both patients underwent AVR without complication. There
was 1 late death due to congestive heart failure. This patient had undergone
AVP + patch angioplasty of the LMT.
| Table 2: |
Preoperative changes in echocardiographic left ventricular
hemodynamic parameters |
 |
AR: Aortic Regurgitation; LVEDD: Left Ventricular
End-Diastric Dimension; LVESD: Left Ventricular End-Systolic Dimension;
LVEF: Left Ventricular Ejection Fraction; FS: Fractional Shortening |
Actuarial survival rate was 90+7% at 5 years. Actuarial freedom from
aortic re-operation was 87 ± 12% at 3 years and 76 ± 23% at
5 years.
DISCUSSION
Valvoplasty for bicuspid AR generated generally satisfactory early
and midterm postoperative results. The 5-year survival rate was 90 ± 7%,
which is comparable to results reported following valve replacement (Kawazoe
et al., 2001). The freedom from re-operation rate was 76 ± 23%
for the first 5 years after surgery. Casselman et al. (1999) reported
an 87% 5-year free from re-operation rate in a group of patients with
bicuspid valve regurgitation who underwent valve repair. In this study,
the re-operation rate and the worsening of AR require careful re-examination
of our procedures.
Bicuspid aortic valve repair creates a non-physiologic valve form. The
line of coaptation of the bicuspid valve does not form an arch, but is
straight and the reconstructed bicuspid valve does not form a true tricuspid
valve. Subcommissural annuloplasty increases the coaptation tension and
helps prevent reflux, but restricts the size of the valvular opening and
increases the risk of stenosis. Furthermore, considering that the line
of coaptation is supported at only two points along the commissure, the
reconstruction must take into account tissue durability at the line of
coaptation and the area of plication. It is evident that reconstructive
procedures for tricuspid AR are fundamentally different from those for
bicuspid AR.
Two patients developed aortic stenosis after valvuloplasty. We think
there are at least two causes. One is overly aggressive subcommissural
annuloplasty to connect the cusp, another is, in the systolic phase, the
leaflet that was repaired by a few interrupted stitches may have restricted
motion and this could cause the reduced opening area. In both patients,
the extent of stenosis as determined intra-operatively depended on systemic
hemodynamics. The cardiac indices were 4.6 and 4.0 1/min/m2,
which reflect a hyperdynamic state. However, the interpretation of these
data depended on the surgeon. In this series, there were no criteria for
determining the extent of stenosis after repair. However, the data showed
that the pressure gradient tended to have improved by the time of discharge
and the patients were asymptomatic. No patient who required re-operation
developed aortic stenosis during follow-up.
Two patients required re-operation for complications related to dehiscence
of the repair. This class of problems has been discussed by Fraser and
Cosgrove (2001). We have reported several modifications of techniques
for aortic valve repair.
Compared with annuloplasty using a pledget, this technique does a better
job of reinforcing the commissure and reducing tension in this area through
the use of Gore-tex material (Izumoto et al., 1995). The philosophy
underlying this approach is that extra care must be taken to protect tissue
damaged by previous surgery.
Izumoto et al. (1995) found that only slight or no calcification
occurs in 96% of cases of bicuspid aortic insufficiency. However, it is
widely accepted that a bicuspid aortic valve develops severe stenosis
with shortened, hypertrophic and calcified cusps, with aging. It is also
believed that aortic stenosis progresses rapidly once the cusps become
calcified. In addition, a bicuspid aortic valve is often associated with
other aortic pathology, such as dilatation, coarctation, cystic medial
necrosis and dissection. The present series did not document a similar
progression of cusp calcification.
There may be some limitations in this study. One of the most important
limitations is the fact that this is a single institutional study of a
relatively small number of patients.
Our experience suggests that treatment must be individualized to obtain
maximum benefit. We believe our data argues aortic valve repair should
continue to be a viable option for aortic valve repair in selected cases.
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