Minimally invasive surgical closure for doubly committed subarterial ventricular septal defects through a right subaxillary thoracotomy

INTRODUCTION

Median sternotomy is considered the standard approach for the treatment of congenital heart defects (CHDs). However, because of undesirable cosmetic results and sternotomy-related complications, an increasing number of surgeons prefer not to use this method for common CHD procedures [1]. With advancements in surgical techniques and devices, the mortality rate of simple CHDs such as atrial septal defect (ASD) or ventricular septal defect (VSD) approaches zero [2, 3]. With the goal of accomplishing a perfect correction, cosmetic results have become more important in the evaluation of these procedures. In recent years, several minimally invasive cardiac surgery techniques [4–8] have been increasingly explored to achieve favourable cosmetic results and an excellent repair.

MATERIALS AND METHODS

The study included 78 selected patients who underwent doubly committed subarterial VSD closure through a right subaxillary thoracotomy (RSAT) between October 2009 and September 2015. The inclusion criteria were doubly committed subarterial VSD, left ventricular enlargement visible with echocardiography, noticeable haemodynamic abnormality and frequent respiratory infections. The exclusion criteria were respiratory diseases, a history of a right thorax procedure, body mass index (BMI) greater than 30 kg/m² and severe aortic regurgitation. No patient in this study had another surgical approach to their defect during the procedure. All patients were operated on by the same surgical team. Demographic and clinical data for the patients are listed in Table 1. This study was approved by the ethics committee of our institution, and consent was obtained from the parents.

Operative technique

Surgical techniques for RSAT have been previously described [4, 5, 9, 10]. These include the position of the patient (Fig. 1), a 5- to 8-cm oblique incision (Fig. 1), muscle sparing, entrance to the thoracic cavity through the fourth intercostal space, two retractors used to expose the thoracic cavity and the lung retracted posteriorly with a wet sponge to expose the pericardium and protect the lung. Bilateral superior pericardial stay stitches were used to elevate the heart. After heparinization, cardiopulmonary bypass (CPB) was established routinely through the ascending aorta and bicaval cannulations. Peripheral vascular access for CPB was not used for fear of vascular complications. Cannulation of the ascending aorta, one of the critical steps during the establishment of CPB, was performed as described previously [4]. The tip of the curve of the cannula was nipped by forceps (Fig. 2), contributing to the cannulation. The technique of using a straight arterial cannula was similar to that performed in the median sternotomy. RSAT provided a better visualization of the right atrium. The SVC and IVC cannulations were not difficult; they were similar to those performed in the median sternotomy.

Figure 1:

Patients were placed with the right side elevated ∼60°–75° and the lines (the anterior axillary line, Line I; posterior axillary line, Line II; the fourth intercostal space, Line III) were marked. A 5- to 8-cm oblique incision (Line IV) was made from the third intercostal space along the right mid-axillary line to the sixth rib or intercostal space along the anterior axillary line.

Open in new tabDownload slide

Figure 2:

The tip of the arterial curve cannula was nipped by forceps.

Open in new tabDownload slide

After cardioplegia was administered, a wet sponge was placed beneath the heart in the pericardial cavity and the defect was positioned in a shallower area. The approach to closure was individualized according to the exposure of the main pulmonary artery (MPA). The surgeon chose to close the defect through the incision in the MPA to achieve satisfactory exposure of the MPA; otherwise, the right ventricular outflow tract (RVOT) would be the procedure of choice. In the RVOT group, a longitudinal incision ∼1.5–2.0 cm in length, as short as possible, was created in the RVOT to preserve the branches of the right coronary artery. Generally, it is easier to expose the defect through this approach. In the MPA group, a transverse incision ∼1.5–2.5 cm in length, 1.5–2.0 cm above the pulmonary valve annulus, was created in the MPA. Two drag hooks were placed into the RVOT to expose the defect (Fig. 3). Appropriate traction of the two drag hooks helped to expose the defect; at the same time, the goal was to avoid excessive traction injury to the myocardium. There was some difficulty in exposing the aortic and pulmonary commissural annulus. The defect was closed with a piece of Dacron patch using a running suture or directly with one to two pledgetted polypropylene sutures for a small defect with a firm rim, thereby also preserving the semilunar valves and aortic sinus. The sutures started from the inferior rim of the defect and continued counterclockwise. Dragging the Dacron patch with appropriate traction helped expose the defect. Skilful co-operation between the surgeons helped to complete the procedure. After the defect was closed, the MPA or RVOT incision was closed using a running suture. Other additional procedures included ASD closure (8), patent foramen ovale closure (6), mitral valve commissural plasty (4), tricuspid annuloplasty (2) and relief of RVOT obstruction (2). Before closing the chest, the surgeons performed an intercostal block in the fourth, fifth and sixth intercostal spaces. In addition, the lung was inflated adequately and repeatedly to eliminate the residual air in the thoracic cavity to reduce complications such as subcutaneous emphysema and pneumopericardium. Pericostal sutures were used to close the wound, and the muscles were allowed to return to their normal position.

Figure 3:

A doubly committed subarterial VSD was exposed through the main pulmonary artery incision.

Open in new tabDownload slide

Transthoracic echocardiography was performed before discharge and at the follow-up visit after 3 months, 6 months and 1 year or at additional periodical follow-up visits if necessary. These data and the clinical status at 6 months were available for all patients. The pain after surgery was not measured by any surrogate tools.

RESULTS

All procedures were performed successfully, and conversion to another approach was not required in any of the procedures. The VSDs were approached through the MPA in 64 patients and through the RVOT in 14 patients. The defect was closed with a piece of Dacron patch using a running suture technique in 71 patients and directly with one to two pledgetted polypropylene sutures in 7 patients. No patient required a reoperation for bleeding. Postoperative echocardiography revealed 2 patients with small residual shunts and 1 with mild mitral regurgitation. The incision length was 6.7 ± 1.5 cm (range, 5.0–8.0 cm). The results of the procedures are listed in Table 2.

The follow-up period was 37 ± 27.5 months (range, 6–72 months). There were no perioperative or late deaths during the follow-up period. One small residual shunt detected on echocardiography was healed at the 1-year follow-up visit. No evidence of regression of cardiac function was detected during the follow-up period. The patients were all in New York Heart Association cardiac function Class I. The thoracic incision healed properly in all patients. No chest deformity or asymmetrical development of the breast has been found. The cosmetic advantage of the RSAT approach is noticeable; the scar is often under the armpit and therefore almost invisible (Fig. 4). All patients were satisfied with the cosmetic results during the follow-up period. The main complications of the procedures are listed in Table 3.

Table 3:

Open in new tab

The main complications of the procedures

Variables .	No. .
Arrhythmia	3
Atrial tachycardia	1
Premature atrioventricular junctional contraction	1
Premature ventricular contraction	1
Atelectasis	2
Pneumothorax	1
Subcutaneous emphysema	1
Pulmonary infection	1
Residual shunt	2
Mild mitral regurgitation	1

Variables .	No. .
Arrhythmia	3
Atrial tachycardia	1
Premature atrioventricular junctional contraction	1
Premature ventricular contraction	1
Atelectasis	2
Pneumothorax	1
Subcutaneous emphysema	1
Pulmonary infection	1
Residual shunt	2
Mild mitral regurgitation	1

Table 3:

Open in new tab

The main complications of the procedures

Variables .	No. .
Arrhythmia	3
Atrial tachycardia	1
Premature atrioventricular junctional contraction	1
Premature ventricular contraction	1
Atelectasis	2
Pneumothorax	1
Subcutaneous emphysema	1
Pulmonary infection	1
Residual shunt	2
Mild mitral regurgitation	1

Variables .	No. .
Arrhythmia	3
Atrial tachycardia	1
Premature atrioventricular junctional contraction	1
Premature ventricular contraction	1
Atelectasis	2
Pneumothorax	1
Subcutaneous emphysema	1
Pulmonary infection	1
Residual shunt	2
Mild mitral regurgitation	1

Figure 4:

The excellent cosmetic result of the right subaxillary thoracotomy: the short incision hidden by the resting arm is often invisible.

Open in new tabDownload slide

DISCUSSION

Median sternotomy has been considered the standard approach for the correction of cardiac defects for many years. However, the psychological burden associated with a visible mid-sternotomy scar should be taken into consideration in evaluating the procedure [11], especially for children, teenagers and adult women. In recent years, an increasing number of surgeons have explored minimizing operative trauma and improving cosmetic results [4–6, 12, 13]. On the premise of satisfactory exposure, invisible site and the shortest possible length of the incision remained the focus of the exploration [14]. All of these approaches have proved suboptimal, either with respect to visibility of the scar, limited exposure, chest deformity or asymmetrical development of the breast, especially in young girls.

From 2004, the RSAT approach has been used by our team to correct a wide range of common CHDs. As we accumulated experience with the minithoracotomy used in open heart surgery, we sought in recent years to correct defects of increasing difficulty and to extend the indications for the procedure to the closure of doubly committed subarterial VSDs. The advantages of the RSAT have been previously described [4, 5, 9, 10]. They are similar to those of a median sternotomy: The procedure is familiar to cardiac surgeons, is relatively easy to learn, does not require special surgical instruments and does not increase costs. It is worth emphasizing that the safety of the RSAT procedure is based on satisfactory exposure, smooth establishment of CPB and experienced cardiac surgeons.

The majority of VSDs could be closed through a right atriotomy, with or without tricuspid valve detachment. However, it is difficult to perform a doubly committed subarterial VSD closure through a right atriotomy, which could also be performed through an MPA or RVOT incision. Generally, it is easier to expose the defect through an RVOT incision. To reduce the incidence rate of ventricular arrhythmias, the defect closure should be performed through the MPA incision to the extent possible. However, some researchers [15] have reported that the right ventricular approach did not affect the incidence of ventricular arrhythmias nor was there an increase in the mortality or morbidity rates associated with the RVOT perioperatively or during the follow-up. In our opinion, the RVOT incision is preferable for doubly committed subarterial VSD closure by a beginner. As we acquired experience with this approach, we preferred to close the defect through the MPA incision.

Exposing the defect perfectly through the MPA incision with RSAT is not easy, especially the part of the VSD border around the commissure of the aortic and pulmonary annulus. Better visualization of the defect could be achieved by placing a wet sponge in the pericardial cavity beneath the heart, adjusting the inclination of the operating bed, dragging the two retractors placed into the RVOT or MPA incision appropriately and inserting the Dacron patch. In addition, skillful co-operation between the members of the surgical team contributed to the success of the procedure. Wang and his colleagues [10] reported that better visualization of the defect could be achieved with sutures set through the base of the semilunar valve cusps for the superior border. Furthermore, with our accumulated experience, it was not difficult to perform mitral valve commissuroplasty, tricuspid annuloplasty and ASD or PFO closure through an RSAT.

Attention should be paid to possible pulmonary complications. Besides the pulmonary hypoplasia and the inevitable lung injuries caused by the procedure and CPB, iatrogenic injury during the procedure is another important event to avoid. In this series, 4 patients suffered from pulmonary complications probably caused by iatrogenic injury. Retraction of the right lung posteriorly with a wet sponge reduced the probability of mechanical injuries during the procedure. All of these complications occurred early in this series. As we accumulated experience with the procedure, pulmonary complications caused by iatrogenic injury seldom occurred.

A right vertical infra-axillary thoracotomy [5, 16, 17] along the right mid-axillary line from the second to the fifth ribs has been used to correct simple CHDs and to replace mitral and aortic valves. This access can provide enough exposure of the ascending aorta and both venae cavae. Adequate exposure of the operating field for closure of an ASD or VSD through a right atriotomy, correction of partial atrioventricular septal defects, the procedures for intra-atrial atrium and even double valve replacement can also be obtained through this approach. As we accumulated experience, we were able to extend the indications for this thoracotomy. Wang and his colleagues [10] reported that they performed 14 doubly committed subarterial VSD closures through this approach. However, in our opinion, the exposure of the PDA ligation, total correction of TOF and doubly committed subarterial VSD closure through the right vertical infra-axillary thoracotomy were limited. In contrast, RSAT can provide better exposure. Therefore, we prefer the RSAT approach for procedures that require PDA closure, total correction of mild TOF and doubly committed subarterial VSD closure.

The approach obviates the need to divide or incise any muscles other than the intercostal muscles. Normal thorax development after the RSAT procedure [11, 18, 19] is possible because of the excellent elasticity of the chest and the opportunity to spare the thoracic muscles, preserve the long thoracic nerve and retain a normal space between the ribs. Development of the breast after thoracotomy has been taken into consideration in evaluating the procedure, especially for female patients. Symmetrical development of the breasts after the RSAT procedure also has been previously described [9, 20], probably because of the location of the incision in the submammary area, away from any area of future breast development and never violating the borders of the mammary gland. The limited cutaneous incision and its location in the armpit, where it remains essentially invisible, provide better cosmetic results.

Our study has potential limitations. Because it is an observational retrospective single-institution study, it needs to be confirmed by expanding the sample size and including multicentre trials. Lack of data about the level of pain was another limitation.

CONCLUSIONS

The RSAT provides a feasible alternative to median sternotomy compared with other approaches and yields favourable cosmetic and satisfactory clinical results for doubly committed subarterial VSD closure. Long-term results will be assessed in further clinical studies.

Funding

This work was supported by Qingdao Key Health Discipline and Outstanding Health Professional Development Fund.

Conflict of interest: none declared.

ACKNOWLEDGEMENTS

We gratefully thank all of the colleagues of our cardiac surgery team for their valuable suggestions and work for this study.

REFERENCES