Discussion
PDA is one of the most common congenital heart diseases. Excessive blood
flow to the lungs caused by PDA results in pulmonary congestion,
pulmonary edema and respiratory failure (10). This patency may also
cause cerebral, renal or mesenteric hypoperfusion that leads to serious
complications in intensive care unit (11). Medical management, surgical
ligation or percutaneous closure of PDA are treatment methods used
currently for preterm infants. Percutaneous closure of PDA has really
limited place among the teatment methods although transcatheter
technology advances (12-15).
Indomethacin or ibuprofen is used for the medical treatment of PDA. If
medical treatment is unsuccessful surgical closure is performed. These
drugs have various side effects and may cause thrombocytopenia,
necrotizing enterocolitis, pulmonary edema and bleeding, renal failure
(16). There are even publications suggesting early surgery instead of
medical therapy to save the patients from complications of PDA and
medications. (17,18)
In 1938, Gross was first to ligate PDA successfully (19). With the
improvement in cardiovascular surgery better cosmetic results and less
harm to lung tissue became more important. For this purpose, several
minimally invasive techniques have been tried by surgeons instead of the
conventional methods without affecting the operative results (19,20).
Another choice is transcatheter closure of PDA. With the rapid
development of science and technology new occlusion devices serve to
close PDA in appropriately selected preterms. However, it is still not
routinely occluded in very small infants with birth weight ≤2 kg and
still there is a lack of experience (12). As it is safe and successful
transcathater closure of PDA receives more attention; but there are some
concerns about vascular access, risk of residual shunt, providing the
suitable device, possibility of device migration or embolization and
contrast administration in preterm infants (21,22).
Lateral thoracotomy has been procedure of choice for PDA closure in
preterm infants for over five decades; but it doesn’t have the qualities
that left anterior mini-thoracotomy technique has. Lung injury and
potential long-term spinal and chest wall deformities are potential
risks of lateral thoracotomy (23,24)
Verhaegh et al compared lateral thoracotomy with sternotomy for PDA
closure in preterm infants and they found that the postoperative
pulmonary complication rate was significantly lower in the median
sternotomy patients. This obviously shows that it is important not to
touch lungs as much as possible during operation to avoid lung-related
postoperative complications (23).
Technically, left anterior mini-thoracotomy technique requires short
surgical times (< 20 minutes), offering direct visualization
of the left recurrent laryngeal nerve, thus preventing complications
secondary to its damage, guarantees good surgical exposure of the PDA
(also in patients < 1.5 kg who are not routinely managed
through catheterization). In addition, less trauma to lung tissue
reduces the risk of pulmonary complications. This technique also has
good aesthetical results. This is a simple technique and provides good
exposure and the closest approach to the PDA when compared to the other
thoracotomy incisions. The patient is in the supine position during the
operation with the left chest elevated for anterior mini-thoracotomy.
Supine position provides extra comfort for the surgeon and can be
maintained easily in the operating room or in the intensive care unit.
In case of emergency (for example; massive bleeding) you can easily
convert to sternotomy.
We operated all of our patients in the operating room. Patient was under
the heater till the start of the operation. Sometimes even gentle
traction of pulmonary artery for PDA dissection for better view caused
bradycardia and hypotension so adrenaline infusion was started all of
the patients, preoperatively. Our operation time was generally under 20
minutes. Therefore, time under hypothermia was also not long. Our
lightest baby was 480 g. Interestingly, we operated twins, two sisters,
on the same day and discharged them to home one day apart.
In our study, we especially focused on advantages of the technique on
time and lung related complications and possible surgical complications
related with PDA closure. In our cohort, we didn’t have any
intraoperative bleeding, chylothorax and chylomediastinum; but we had
one left diaphragma elevation. Left diaphragma was plicated and the
patient was successfully discharged. Dissection of PDA for beter view
may be dangerous in some patients who have more fragile PDA tissue than
the others. In these type of cases we prefer clip ligation. In these
cases using a metallic vascular clip allows for limited dissection and
safe occlusion. After the operation air was removed using the underwater
drainage system, the thoracotomy was closed without placing a chest tube
. This may have improved the comfort of the patient after the operation.
48% (13) of the patients were transferred to our center for PDA
closure. After the operation we followed-up the patients for one day in
our neonatal intensive care unit. The day after the operation all of the
13 patients were transferred back to their centers. Transfer of a
preterm patient especially before the surgery is important. If the
patient comes to the surgery in hypothermic condition with loss of
intravenous lines or ventilation problems, this may increase the risk of
the surgery.
Although there was no surgery related mortality, our hospital mortality
rate was 29,6 %. This is higher than most of the prior studies related
to PDA closure in preterms (23-25). As our cohort includes preterm
patients with PDA and serious comorbidities these mortality rates are
connected to complications associated with prematurity, infection and
comorbidities. Five were due to sepsis, one was due to necrotizing
enterocolitis, one was due to hydrops fetalis and one was due to renal
failure with hepatoblastoma.
Of course we have several limitations. First of all a limited population
was retrospectively studied. We only have early and mid-term results but
not long term results. Also we can not compare the technique with
another technique as we did not have another group operated by another
surgical technique. All of these avoid us claiming the superiority of
the technique over other techniques. Also, our short and mid term
results with left anterior mini-thoracotomy technique in preterm infants
are promising.
To conclude, PDA closure with the left anterior mini-thoracotomy method
is advantageous in terms of reducing damage to the already congested
lung, shortening the hypothermia time of the baby by shortening the
procedure time, and has good cosmetic results, especially in very low
birth weight preterm babies. Prospective randomised studies are needed
to compare the technique’s safety and efficiency with other conventional
techniques.
Declaration of conflicting interests: The authors declared no conflicts
of interest with respect to the authorship and/or publication of this
article.
Funding: The authors received no financial support for the research
and/or authorship of this article.