Discussion
VSD is one of the most common congenital heart diseases, accounting for
up to 40% of all congenital cardiac
malformations[5]. Because of fetal heart color
Doppler ultrasound screening and heart murmurs after birth, most VSDs
are detected at birth and are treated in infancy and early childhood.
Only a small percentage of these patients are re-tested in adulthood,
either because VSD was not detected at birth as a result of relatively
low screening levels for congenital cardiac disease decades ago, or
because surgery was delayed for financial reasons. Because of most
patients being asymptomatic, these patients were found to have VSDs in
the course of college entrance examinations or orientation medical
examination in China. With the rapid development of endoscopic
technology over the past ten years, increasing numbers of patients begin
to choose this minimally invasive technique. In addition, compared with
conventional surgery and thoracotomy, total thoracoscopic technology is
favored by patients because there is no metal implant and there is not
much trouble on physical examinations at the company or security check
at airports or railway stations. Results of conventional surgical VSD
patch closure are excellent with low operative mortality and morbidity.
Patients undergoing VSD repair are younger and relatively healthier than
other patients undergoing cardiac surgery, and they are interested in
more cosmetically appealing incisions. Nevertheless, they doubt that the
less invasive approach provides cosmesis at the expense of the excellent
outcomes typical of conventional surgery[6].
The total thoracoscopic technique, with or without robotic surgery, has
been widely used for ASD repair, VSD repair, mitral valve repair or
replacement, tricuspid valve repair or replacement, ablation of atrial
fibrillation, resection of cardiac myxoma, and even coronary bypass
grafting[7-12]. However, in China, because robots
are expensive, only a handful of hospitals have robots to perform
surgery. Chinese surgeons tried to perform total thoracoscopic
procedures without the aid of robots. At present, almost all clinical
studies have shown that the mortality and complication rates of total
thoracoscopic surgery are not inferior to those of median thoracotomy,
and the former affords less bleeding, faster recovery and less trauma.
Our institution’s comparative outcomes also support the conclusion that
total thoracoscopic VSD repair results in similar excellent results as
those of mini-sternotomy. Although the mean CPB and ACC time in the
total thoracoscope group were significantly longer than those of the
mini-sternotomy group, few postoperative complications were suffered in
the thoracoscopy group. Although the difference in tracheal intubation
time, ICU time, postoperative hospital-stay time and chest drainage did
not reach statistical significance, these variables tended to be lower
in the thoracoscopy group, which possibly demonstrating the superiority
of less bleeding, faster recovery and less trauma.
Our institution believes that the perimembranous, membranous or inlet
VSD are more suitable for total thoracoscopic surgery. If pouch
formation of the septal leaflet of the tricuspid valve or multiple
chordae tendineae cross over the defect, the detachment of septal
leaflet of tricuspid valve is performed to expose these VSDs. Perhaps
traditionalists remain concerned that detachment may increase the
incidence of iatrogenic complications such as atrioventricular
conduction block and tricuspid valve insufficiency. However, tricuspid
valve detachment has been previously shown excellent
outcomes[13-16]. Our results also suggest the
detachment was a safe and effective technique. Twenty-four patients
underwent tricuspid valve detachment in our study and none showed
atrioventricular conduction block or tricuspid regurgitation. By
contrast, outlet ventricular septal defects are difficult to expose in
the visual field of the thoracoscopic approach, and the surgical
instruments are usually not long enough because of the depth of the
thorax in adults. Muscular VSDs are usually situated near the apex and
often have many outlets on the right ventricular side. As a result, if
thoracoscopy is used, residual shunt is more likely to occur, so
muscular ventricular septal defects are more suitable
interventions[17, 18].
Total thoracoscopic surgery is not available for all patients. If
patients have concomitant thoracic deformities, pleural adhesions,
femoral artery or aortic malformations, severe aortic atherosclerosis,
or other cardiac malformations (patent ductus arteriosus, persistent
left superior vena cava), total thoracoscopic surgery is not
appropriate. At our institution, if thoracoscopic surgery is required,
thoracic CT and total aortic CT should be performed before surgery to
exclude these concomitant diseases, so as to avoid intraoperative
transition to surgery due to severe pleural adhesions, or failure to
perform peripheral femoral arteriovenous cannulation due to femoral
artery malformation, or aortic dissection due to severe aortic
atherosclerosis.
Of course, total thoracoscopic surgery is not without its disadvantages
and limitations. Although total thoracoscopy reduces the incision and
trauma in the chest, it increases use of neck and groin vessels, thereby
increasing the risk of peripheral nerve or vessel injuries such as
femoral arteriovenous stenosis, femoral arteriovenous fistula, femoral
nerve injury, and jugular arteriovenous fistula. Attention should be
paid to vascular dissociation and vascular puncture and intubation
operation to avoid injury. The intubation operation should be soft, and
if the operation run into resistance, forced insertion should not be
carried out to avoid vascular injury or even femoral artery dissection.
There was one case of retrograde aortic dissection caused by femoral
artery cannulation in our center in the early stages of total
thoracoscopic surgery. In addition, due to the need for double lumen
endotracheal tube intubation with a transient single lung ventilation
strategy in total thoracoscopic surgery, postoperative atelectasis or
pneumothorax often occurs.