Discussion
Since the classification of Rastelli, CAVSD is a congenital anomaly, the
anatomy of which is well known and operated with very successful
outcomes with the contribution of developing technology and surgical
techniques. Coexisting additional anomalies do not affect the outcomes
with low morbidity and mortality. Andrew et al. stated that there was no
difference between a single patch or a two-patch in terms of residual
lesion or valve regurgitation in trisomy 21 cases.12İxe et al. reported the optimal surgical time as 3-6 months in among
their patients to who have been operated 92% by TPT and 2.2% the
single-patch technique. Besides they have observed that Down syndrome
was not a risk factor for reoperation.13 On the other
hand, Tumanyan at al compared 214 patients with only CAVSD to 163
patients with concomitant Down syndrome. They have applied the TPT to
75.4% and the single-patch technique to 24.6%. Although the researcher
could not find a difference in terms of the repair technique, he stated
that the additional morbidity of Down syndrome patients compared to
patients without this accompanying disorder, affected the recovery
period and life expectancy.14 In our cases, as can be
seen from the table, the coexistence of additional cardiac anomalies and
Down syndrome (65%) is quite common. However, like other anomalies,
trisomy 21 did not cause additional morbidity and mortality, which
revealed statistical significance.
CAVSD malformations are patients with AV junction defect and a common
single complete AV valve.15-16 In CAVSD, the increased
flow due to a large defect may increase pulmonary pressure very
early.1 This does not cause problems due to high
pulmonary resistance in the first 3 months. Full correction surgery in
the early period prevents pulmonary vascular disease. In this sense,
CAVSD repair should be performed in an average of 4 months. Bakhtiari
and Rudid Takacs reported an operation time in the 3.8 months on average
in their series.17 In our series, the fact that there
were 23(%41) patients who have right ventricle outflow truct stenosis
and pulmonary banding due to additional anomalies. Mean and median age
of these patients are 17 and 33 months respectively. Nevertheless,
almost all of our patients came from abroad and from regions where early
diagnosis-treatment remained insufficient caused the our median
operation timing to be the 7,5 months in MSP and the 14 months in TPT,
and the mean average was the 9 months. However, there were no serious
problems related to pulmonary hypertension, and just 4 of 6 patients who
had undergone pulmonary banding before required NO2inhalation.
Transthoracic echocardiography or even perinatal echocardiography is
sufficient for diagnosis. Cohen GA reported that intraoperative
transesophageal echocardiography (TEE) would be highly an instructive
guiding and beneficial examination during CAVSD repair as in all
congenital heart disease surgeries.18 Approximately
35% of our cases were performed under guidance of intraoperative TEE.
Cardiac catheterization, magnetic resonance imaging, and computerized
tomography should be performed at an advanced age to measure pulmonary
pressure reversibility or if evaluation for additional anomaly is
required.
The MSP has been used more frequently in the last decade, in addition to
the conventional single-patch and TPT that have been used in the
past.8
In this retrospective study, 66% of the cases were operated with MSP
technique, while 34% were operated with the TPT. The conventional
single-patch technique was not preferred in our center like in many
centers. In our series, the VSD diameter was found to be smaller and ACC
and CPB times were found to be shorter in the MSP technique. Li et al.
compared the MSP and TPT in terms of many parameters (VSD diameter,
CPB-ACC time, mortality, reoperation). As in our series, the VSD
diameter was smaller and the CBP and ACC times were shorter in MSP, and
there was no significant difference in other
parameters.(19) Jeong IS and Pan G found only CPB and
ACC time and hence ischemia time shorter in the use of a modified single
patch, while they found other parameters to be
similar.20-21
In the study, short CPB and ACC time did not create a significant
difference in the intubation time, duration of intensive care and
hospitalization, in accordance with the literature. Moreover, the amount
of drainage was significantly higher in TPT, but there was no
significant difference in the use of blood products. This is also
compatible with our institutional policy that we use restricted
blood-blood products for drainages not causing clinical and hemodynamic
deteriotaion.22
The late outcomes of the both tecniques were analysed in the literature,
there was no statistically significant difference.23The most important factor affecting the late period outcomes is the
incidence of reoperations. Ginde S et al. followed 198 patients for an
average of 17.2 years and found LAVV regurgitation as the most common
cause of reoperation. In this series, the 30-year no-reoperation rate is
78%, while the 10-year rate is 88%.24 Prifti and
Massimo stated that left LAVV malfunctions during the primary repair of
CAVSD were important risk factor for reoperations.25In our study where we compared TPT and MSP, performed mostly,
moderate-severe LAVV regurgitation was observed statistically
significantly less in the MSP group in the postoperative early and
middle period. The reduced three-dimensional calculations in the MSP
technique, the number of patches and the easy applicability of the
technique cause this result. Graham Nunn reported 1.6% mortality and
2.3% residual VSD in 128 patients in whom he applied MSP in his series,
while he did not report valve regurgitation in these patients. In the
mean time he observed late-stage LAVV regurgitation to be 0% and LVOTO
to be 2.3% in 46 patients to whom he applied a
two-patch.8 LVOTO was not observed in any of our
groups.
When the two techniques are compared conventionally, reoperation rates
emerge as the most important difference. LVOTO is not observed in the
MSP, whereas reoperation rates can increase up to 15% due to LVOTO in
the TPT. Mortality rates are 1.2% in the MSP and 3.5% in the TPT.
Reoperation rates due to the AV valve are 2.2% and 7.2%, and pacemaker
rates are 0.4% and 1.9%, respectively.26-27 In our
series, while there was no difference in terms of mortality and
pacemaker implantation, our overall pacemaker average was observed to be
above the average indicated in the literature (4%). While the AV block
risk was 2-2.5% in general in the TPT, it is between 0-1% in many
series in which the MSP is applied.26
The most common cause of reoperation after additional AV valve repair is
recurrent LAVV regurgitation (9-17%).28-29 However,
as can be seen from the above-mentioned rates, the reoperation rates
(2.2%) are quite low in the MSP. Some studies have stated that the most
important cause of left ventricular AV valve regurgitation is annular
dilatation, which is related to the operation timing.30-31 In addition to its ease to perform between 2-4
months, reduces reoperation rates. Delayed surgical timing and LAVV
insufficiency are regarded as important risk factors for
reoperation.13 Although LAVV insuffiency as a cause of
reoparation was more frequent in our series, both could not be
identified as a risk factors in our study. However, this result may have
been obtained with the positive effect of the MSP technique applied at a
high rate of 66% on LAVV insufficiency in our series. Alhough our
patients operation timing was later that the recommended time in the
literature, no difference was found in long terms of reoperation and
mortality when the two techniques were compared.
The most significant advantage of the MSP technique is eliminating
complications that may occur due to the dimensions of this patch by not
placing a VSD patch. The non-splitting of the valve prevents tissue loss
from the valves, thus eliminating another technical cause that may
contribute to AV valve regurgitation. The mortality in reoperations due
to left AV valve residual defect and other reoperation causes is about
9.8%.26 The rate of LVOTO is usually 4.2%. While
Geoffrion et al. presented this rate as 0.6% in their series, the rate
was reported to be 0 % in Nunn’s series in the MSP technique.26-27
In conclusion, when the modified single-patch technique is compared with
the two-patch technique in this series, the CPB-ACC time is shorter in
favor of MSP, the VSD is smaller in accordance with the nature of the
technique, LAVV regurgitation is less, and, accordingly, the risk of AV
valve reoperation is lower. Therefore MSP technique may be prefeferred
in patients with suitable VSD diameter and localization in CAVSD.