Original Articles: Cardiovascular Minimally Invasive Cardiac Surgical Techniques in the Closure of Ventricular Septal Defect: An Alternative Approach Pyng Jing Lin, MD, Chau-Hsiung Chang, MD,

 

 Jaw-Ji Chu, MD, Hui-Ping Liu, MD, Feng-Chun Tsai, MD, Wen-Jen Su, MD, Min-Wen Yang, MD, Peter P. C. Tan, MD

 

Division of Thoracic and Cardiovascular Surgery, Chang Gung Memorial Hospital, Chang Gung Medical College, Taipei, Taiwan Department of Pediatrics,

 

 

 

Chang Gung Memorial Hospital, Chang Gung Medical College, Taipei, Taiwan Department of Anesthesiology, Chang Gung Memorial Hospital, Chang Gung Medical College, Taipei, Taiwan Accepted for publication July 5, 1997. Dr Lin, Division of Thoracic and Cardiovascular Surgery, Children’s Hospital, Chang Gung Memorial Hospital, Chang Gung Medical College, 199, Tun-Hwa North Rd, Taipei, Taiwan.

 

Abstract

 

Background. Minimally invasive cardiac surgical techniques recently have been applied in the management of a variety of intracardiac lesions.

 

Methods. Fourteen patients (6 boys and 8 girls; age, 8.9 ± 5.5 years; body weight, 29.0 ± 13.5 kg) were operated on using minimally invasive cardiac surgical techniques for the closure of a ventricular septal defect (subarterial in 11 patients and perimembranous in 3 patients). The operations were performed through a left anterior minithoracotomy and were guided by video-assisted endoscopic techniques under femorofemoral cardiopulmonary bypass. The myocardium was protected by continuous coronary perfusion with hypothermic fibrillatory arrest. The right ventricular outflow tract was entered after pericardiotomy was performed.

 

Results. Closure of the defect (directly in 4 patients and by patch in 10 patients) was performed successfully in all patients. A right ventricular outflow tract obstruction and ruptured sinus of Valsalva aneurysm also were repaired in 1 patient each. The duration of cardiopulmonary bypass was 41 ± 10 minutes (range, 28 to 100 minutes) and the total operative time was 2.2 ± 0.8 hours (range, 1.3 to 3.5 hours). All the patients recovered rapidly from their operation and had an uneventful postoperative course. Follow-up (mean, 6.2 months; range, 6 to 9 months) was complete in all patients. There were no late deaths. Transthoracic echocardiographic examination showed no residual shunt and no aortic regurgitation in all patients.

 

Conclusions. Our experience demonstrates that minimally invasive cardiac surgical techniques are technically feasible and an alternative option for the repair of a ventricular septal defect.

 

Introduction

 

Video-assisted endoscopic techniques have been used in many surgical subspecialties to reduce incisional pain and shorten the hospital stay. Advances in video instrumentation have made minimally invasive thoracic operations possible [1][2][3][4]. These operations have been used in the treatment of coronary artery disease and the repair of congenital cardiac lesions when the use of cardiopulmonary bypass was not required [5][6][7][8][9][10]. Recently, minimally invasive cardiac surgical techniques have been used to repair intracardiac lesions, congenital or acquired, through a right or left anterior minithoracotomy [11][12][13][14][15]. Our experience showed that closure of an atrial septal defect could be performed safely with the use of video-assisted endoscopic techniques under femorofemoral or femoral-right atrial cardiopulmonary bypass.

 

Median sternotomy is the standard approach for surgical intervention in ventricular septal defect (VSD). However, the use of minimally invasive cardiac surgical techniques might be an alternative approach in the surgical treatment of VSD. We report our experience with the use of minimally invasive cardiac surgical techniques in the closure of VSD in 14 pediatric patients.

 

Material and Methods

 

Fourteen selected patients were operated on for VSD and associated cardiac lesions from March to September 1996. There were 6 boys and 8 girls with a mean age of 6.3 ± 5.0 years (range, 1.5 to 18.9 years). Their mean body weight was 29.0 ± 13.5 kg (range, 13.1 to 59.0 kg). Transthoracic echocardiography and cardiac catheterization confirmed the diagnosis of VSD. The location of the VSD was subarterial in 11 patients and perimembranous in 3 patients. Prolapse of the aortic cusp was noted in 10 patients, with mild aortic regurgitation in 7 patients. The pulmonary-to-systemic flow ratio was 1.9 ± 0.3 (range, 1.5 to 2.6). The mean pulmonary artery pressure was 20 ± 3 mm Hg (range, 16 to 24 mm Hg). Infundibular stenosis was observed in 1 patient, with a pressure gradient across the right ventricular outflow tract of 57 mm Hg. A right sinus of Valsalva aneurysm ruptured into the right ventricle also was seen in 1 patient. The operative policy to use minimally invasive cardiac surgical techniques for the closure of VSD was approved by the appropriate hospital authorities. Written consent was obtained from the family members before operation.

 

After the induction of general anesthesia, transesophageal echocardiographic monitoring was set up and the diagnosis of VSD was confirmed. The patient was placed in a supine position with the left groin exposed. Cardiopulmonary bypass was established through cannulation of the left femoral artery with an aortic cannula (THI aortic perfusion cannula; Argyle, Division of Sherwood Medical, St. Louis, MO) and the left femoral vein with a chest tube (10F to 28F thoracic catheter; Mallinckrodt Laboratories, Athlone, Ireland), up to the level of the diaphragm. A membranous oxygenator (Maxima Plus oxygenation system; Medtronic, Inc, Cardiopulmonary Division, Anaheim, CA) was used. Systemic hypothermia was begun immediately after the initiation of cardiopulmonary bypass.

 

A left anterior parasternal minithoracotomy (4- to 6-cm; Fig 1) was performed and the pleural space was entered through the third or fourth intercostal space in patients with a subarterial or perimembranous VSD. The third or fourth costal cartilage sometimes was divided, without resection, to increase exposure. The left internal thoracic artery was well preserved. A 10-mm endoscope (Stryker Endoscopy, San Jose, CA) and other conventional surgical instruments were introduced through the thoracotomy. Because the length of both the thoracotomy and the ventriculotomy was short, illumination during repair of the VSD usually was not good. The video-assisted endoscope was used to provide illumination and guide the repair procedure.

 

 

 

Incision sites. The arrow indicates the thoracotomy incision created in the parasternal fourth intercostal space.

 

The left phrenic nerve was identified and the pericardium was incised carefully longitudinally anterior to the phrenic nerve to expose the right ventricle. The aorta was not cross-clamped. The heart was protected with continuous coronary perfusion with hypothermic fibrillatory arrest (rectal temperature, 27.3° ± 3.0°C).

 

Topical cooling of the heart was used to facilitate fibrillation. After the heart fibrillated, a 1- to 2-cm incision was made in the right ventricular outflow tract, which then was entered (Fig 2A). Care was taken to avoid injury to the major coronary artery branches. A cardiotomy suction tube was inserted into the right ventricle and the VSD was identified with the assistance of the endoscope by means of projected images on the video monitor. In patients with mild aortic regurgitation, a suction catheter (left ventricular sump vent catheter with Cath-Lok and sentinel line; Argyle, Division of Sherwood Medical) was inserted through a stab incision on the apex of the left ventricle. Conventional hand suturing for closure of the VSD and ventriculotomy was performed smoothly through the thoracotomy, guided by the endoscope.

 

Pictures of the closure of a ventricular septal defect (VSD) taken by a video-assisted endoscope. (A) After pericardiotomy, the right ventricular outflow tract was entered. (B) Interrupted sutures were placed. The arrowhead indicates a small suction tube inserted into the left ventricle through the VSD to expose the margin of the VSD. (C) The VSD was closed directly. (D) The right ventriculotomy was closed with a running suture.

 

The VSD was found to be of the subarterial type in 11 patients and the perimembranous type in 3 patients. A small tube connected to the cardiotomy suction system was inserted into the left ventricle through the VSD to outline the margin of the VSD (Fig 2B). The VSD was closed directly with 4-0 polypropylene (Prolene; Ethicon, Ltd, United Kingdom) interrupted sutures (Fig 2C) in 4 patients. In the other 10 patients, the VSD was closed with a knitted Dacron patch (Meadox Medicals, Inc, Oakland, NJ).

 

In 1 patient with a right sinus of Valsalva aneurysm ruptured into the right ventricle, the ascending aorta was cross-clamped. Crystalloid cardioplegic solution (Plegisol; Abbott Laboratories, North Chicago, IL) was infused into the coronary orifices after oblique aortotomy. The sinus of Valsalva fistula was patched closed from the aortic and right ventricular side.

 

Before complete closure of the VSD, the air in the left ventricle was evacuated carefully by rotation of the operating table in all directions and expansion of both lungs. A venting needle was applied in the apex of the left ventricle to evacuate the residual air when necessary. There was no obvious air bubble in the left atrium or left ventricle noted on transesophageal echocardiographic examination. The patient was changed to a head-down position. Cardioversion was performed easily by placing the cardioverter pads (CodeMaster; Hewlett-Packard Company, McMinnville, OR) on the surface of the heart. Sinus rhythm was recovered in all patients. The hypertrophic infundibular muscle of the patient with infundibular stenosis was resected and the right ventricular outflow tract was patched with autologous pericardium. The right ventriculotomy of the other patients then was closed directly with running suture (Fig 2D).

 

Cardiopulmonary bypass was terminated after rewarming of the patient. The femoral arteriotomy and venotomy were closed with 5-0 and 6-0 Prolene interrupted sutures. Transesophageal echocardiographic examination showed complete closure of the VSD without any residual shunt. The pericardium was closed loosely with interrupted sutures. Dobutamine and sodium nitroprusside were not used. There was no atrioventricular block. However, a temporary pacemaker system was set up. The pleural drainage tube was inserted. Hemostasis and closure of the incisions were achieved easily.

 

Results

 

The VSD was closed successfully in all patients, by direct means in 4 patients and with the use of a patch in 10 patients. The infundibular stenosis and ruptured right sinus of Valsalva aneurysm in 1 patient each also were repaired. The duration of cardiopulmonary bypass was 41 ± 10 minutes (range, 28 to 100 minutes). The lowest rectal temperature during cardiopulmonary bypass was 27.3° ± 3.0°C. The duration of operation, from the first incision to complete closure of all incisions, was 2.2 ± 0.8 hours (range, 1.3 to 3.5 hours). All the patients regained consciousness promptly after operation. The endotracheal tube was removed on the first postoperative night. The mean amount of drainage during the first 24 hours after operation was 71 mL (range, 50 to 100 mL).

 

The patients were transferred out of the intensive care unit on the first postoperative day. There was no organ failure during the postoperative course, which was uneventful overall. The mean postoperative hospital stay was 4.1 days (range, 3 to 5 days). Follow-up was complete on all patients for a mean of 6.2 months (range, 3 to 9 months). There were no wound, neurologic, or lower limb vascular complications. There was no limitation in the activity of the patients. Follow-up transthoracic echocardiographic examination did not show any residual shunt or ventricular dysfunction. All the patients were doing well.

 

Comment

 

In this study, 14 patients were operated on to close a VSD with the use of minimally invasive cardiac surgical techniques. All patients recovered rapidly from the operation.

 

Median sternotomy is the standard surgical approach in the repair of VSD [16]. For better cosmetic healing, bilateral submammary skin incisions with the sternum incised vertically may be used as an alternative to the midline skin incision. However, long midline or thoracotomy skin incisions, postoperative pain, poor cosmetic effects, mediastinitis, and osteomyelitis occasionally make the repair of VSD troublesome.

 

Since the early 1990s, video-assisted endoscopic techniques have been a useful and rapidly expanding modality for the surgical treatment of intrathoracic disease [1][2][3][4]. They offer the promise of expediency, safety, minimal discomfort, reduced postoperative pain, quick functional recuperation, excellent cosmetic healing, shortened hospital stay, and cost savings [3]. The use of these techniques in the field of cardiovascular surgery is just beginning. They have been used in the surgical repair of patent ductus arteriosus and vascular ring, and in coronary artery bypass grafting [5][6][7][8][9][10]. Recently, our group and others [11][12][13][14][15] have used minimally invasive cardiac surgical techniques as an alternative approach to the repair of intracardiac lesions, atrial septal defects, and valvular lesions. Using these techniques, the heart is approached by a video-assisted endoscope inserted through a thoracotomy and the intracardiac lesions are repaired through a small manipulation incision made over a right anterolateral minithoracotomy. In this series, the VSD of 14 patients was repaired successfully with the use of minimally invasive cardiac surgical techniques through a left anterior minithoracotomy, indicating that this approach is technically feasible in the surgical correction of VSD.

 

In open heart operations, cardiopulmonary bypass can be performed with good results through cannulation of the femoral artery and vein [17][18][19]. In our previous experience with minimally invasive cardiac surgical techniques and that of others [11][12][13][14][15], simple femorofemoral bypass established satisfactory perfusion of all vital organs, including the brain, with minimal complications. In this series, there was no postoperative organ failure, and the patients regained consciousness promptly after operation, indicating that there was adequate tissue perfusion during femorofemoral cardiopulmonary bypass. There were no obvious lower limb vascular complications during the follow-up period and no limitations in the activity of the patients. Noninvasive studies of the arterial and venous condition of the lower limbs of these patients is now undertaken at our institution.

 

The infusion of cardioplegic solution is the standard procedure for myocardial protection. However, continuous perfusion of the heart without cross-clamping of the ascending aorta also can offer adequate myocardial protection in selected coronary artery bypass grafting procedures [20][21] or during minimally invasive cardiac surgical techniques [11][12][13][14]. In our patients, with the use of continuous coronary perfusion under hypothermic fibrillatory arrest without aortic cross-clamping, there were no cases of postoperative low cardiac output, indicating that adequate myocardial protection was provided. However, cross-clamping of the ascending aorta with the infusion of cardioplegic solution also was technically possible and was used in 1 patient.

 

The repair of a subarterial VSD can be accomplished through a pulmonary arteriotomy [22]. The right atrial approach is the route of choice for the closure of other types of VSD. However, exposure of a perimembranous VSD through a right anterior minithoracotomy is rather difficult. Exposure of a subarterial VSD through a pulmonary arteriotomy also is limited by the small incision of a left anterior minithoracotomy. Our previous experience [23] showed that the transventricular approach could provide excellent exposure for subarterial and perimembranous VSDs. Right atriotomy could reduce the prevalence of right bundle branch block, but it does not prevent late atrioventricular block [24]. The prevalence of ventricular arrhythmias increased with the duration of follow-up and the age of the patient at evaluation, regardless of the surgical approach used (ie, right atrium or ventricle) [24][25]. In this series, there was no significant adverse effect on mortality or morbidity associated with the use of the right ventricular approach. Exposure of the VSD through the right ventricular outflow tract, with the aid of a video-assisted endoscope, was excellent and closure of the VSD was accomplished easily. Follow-up transthoracic echocardiographic examination did not show any ventricular dysfunction. However, close long-term follow-up is mandatory.

 

The duration of cardiopulmonary bypass in this series (41 ± 10 minutes) was slightly longer because of the use of hypothermia. However, the operative time (2.2 ± 0.8 hours) seemed acceptable because of the minimally invasive nature of the procedure. In the future, it will be possible to shorten the duration of cardiopulmonary bypass by using mild hypothermia and topical cooling.

 

The removal of air is an important procedure in cardiac operations, especially with minimally invasive cardiac surgical techniques [11][12][13][14]. We rotated the operating table in all directions and ventilated both lungs to remove air before completely closing the VSD. A venting needle was used in the apex of the left ventricle to evacuate the residual air when necessary. The patients were kept in a head-down position. Before the heart started beating, transesophageal echocardiographic examination showed no obvious air bubbles in the heart chambers. All our patients woke up from anesthesia promptly after arriving at the intensive care unit. There was no postoperative evidence of neurologic defects, indicating that air removal was adequate.

 

The major advantage of minimally invasive cardiac surgical techniques is the avoidance of sternotomy and intervention in the aorta [10][11][12][13]. The minimally invasive nature of this approach might reduce the incidence of postoperative complications to a minimum [8]. There were no wound infections or cases of mediastinitis among our patients. The cosmetic healing was excellent (Fig 1). The amount of drainage during the first 24 hours after operation was only 72 mL (range, 50 to 100 mL), illustrating the advantage of minimally invasive cardiac surgical techniques. The postoperative hospital stay was significantly shorter in this series (mean, 4.1 days) than it is with uncomplicated VSD closure performed by median sternotomy (mean, 8.2 days; unpublished data) [7][9][10][14][15][26]. However, the number of patients in this series is too small to allow for meaningful statistical comparison with data from patients who have undergone median sternotomy. Before the general application of minimally invasive cardiac surgical techniques is recommended, further long-term analysis of a larger series with comparative data from conventional approaches is necessary.

 

Our experience showed that minimally invasive cardiac surgical techniques are technically feasible in the closure of VSD and can be carried out safely and effectively. The minimally invasive nature of this approach decreased the amount of postoperative bleeding and produced excellent cosmetic healing. It also shortened the postoperative hospital stay and, therefore, might reduce medical costs, as do thoracoscopic and laparoscopic techniques. Our experience demonstrates that minimally invasive cardiac surgical techniques can be used as an alternative approach for the repair of VSD.

 

References

 

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COURTESY

 

The Annals of Thoracic surgery