Ann Thorac Surg 2008;85:1067-1071. doi:10.1016/j.athoracsur.2007.10.048
© 2008 The Society of Thoracic Surgeons
New Technology
A New Minimally Invasive Technique to Occlude Ventricular Septal Defect Using an Occluder Device
Feng Li, MD*,
Ming Chen, MD,
ZhaoKun Qiu, MD,
Jing Lu, MD,
WeiHua Wu, MD
Department of Cardiovascular Surgery, Shanghai Chest Hospital, Shanghai, China
Accepted for publication October 10, 2007.
* Address correspondence to Dr Li, Room 101, No. 16, Lane 768, South Qinzhou Rd, Shanghai, 200233, China (Email: ciqic{at}online.sh.cn).
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Abstract
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Purpose: This study was to evaluate ventricular septal defect occlusion using a lower mini-sternotomy approach.
Description: Eleven cases with ventricular septal defect underwent general anesthesia and a 3 to 4 cm lower mini-sternotomy incision was made. Using transesophageal echocardiography, the occluder was released using a mono-tubed unit.
Evaluation: All cases were occluded successfully. No patient required open heart surgery using extracorporeal circulation. There were no major complications and no evidence of residual ventricular shunt.
Conclusions: Ventricular septal defect occlusion through a minimal surgical incision is safe, less invasive, and has an excellent outcome.
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Introduction
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Ventricular septal defect (VSD) is one of the most common congenital heart defects. There are now two therapeutic approaches: (1) open heart surgery using cardiopulmonary bypass (CPB) and (2) interventional transcatheter occlusion for part of a suitable VSD. Surgery is safe with an excellent outcome for all types of VSD, but it is invasive, which might lead to increased postoperative morbidity, prolonged hospital stay, and possible late neurocognitive impairment [1, 2]. The transcatheter occlusion is minimally invasive, but can be complex and time consuming, as well as difficult to control when complications arise [3–5]. Also, only part of VSD can be treated with transcatheter occlusion. The present series documents our recent experience with a minimally invasive surgical approach to occlude VSDs.
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Technology
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Material and Methods
The Ethics Committee of Shanghai Chest Hospital approved this study before we selected the patients to do the procedure on. Individual patient consents were obtained for the study before surgery.
Patients
From June 2006 through December 2006, 11 patients with VSD undergoing VSD closure with an Amplatzer device (Shanghai Memory Alloy Company, Shanghai, China) using a small lower sternotomy approach at Shanghai Chest Hospital, were retrospectively studied. In this group, there were 4 males and 7 females, and the ages ranged from 2 to 25 years of age (mean age, 14.6 years). The diameter of the VSD was 3 mm to 6 mm. The patient data are listed in Table 1.
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Technique
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Device and Deployment
The occluder system is composed of an Amplatzer VSD occluder and its sheath (Shanghai Memory Alloy Company). The occluder is woven to form two disks with a connecting waist and a sheath with a pusher. The wires are shaped to form double discs, with a short connecting waist measuring 1.5 mm. Dacron (DuPont, Wilmington, DE) is sewn inside the discs to decrease shunting through the wire mesh. The device is self-expandable and fully retrievable to the point of release. The size of the device corresponds to the waist of the device.
There are 2 types of occluders: (1) the concentric type (ie, normal type), in which the edge of both ventricular sides is the same (ie, both are 2 mm larger than the waist), and (2) the zero-rim type, in which the edge of the left ventricular disc, which is to face the aortic valve, is 0 mm larger than the waist to prevent impingement of the aortic valve. The edge of the disc opposite the aortic valve is 5 mm larger than the waist. The right ventricular disc is 2 mm larger than the waist all around its circumference.
A female screw is welded in the center of the right disc for attachment to the delivery cable. Therefore, the occluder can be pushed by the pusher and pulled by the pusher more than 10 times, if needed for adjustment purposes.
Periventricular Technique
All operations were performed under general endotracheal anesthesia. Preoperative and postoperative transesophageal echocardiography (TEE) (HP Sonus 4500 Doppler, 4 to 7 mHz; Hewlett-Packard Company, Palo Alto, CA) was used in 11 cases. The 2-cm to 3-cm lower stern incision extended from the xiphoid to the place of the left fourth intercostal space (ie, the incision of patient 4 was a total sternotomy for reoperation), and then a left turn was made to cut the stern. The pericardium was opened vertically and marsupialized to the skin. Two pursestrings were placed on the free wall of the right ventricle using a 4-0 polypropylene (Prolene [Ethicon, Somerville, NJ]) suture. Then heparin (1 mg/kg intravenously) was administrated systemically. Transesophageal echocardiography was performed to measure the exact size and location of the VSD. The integrity was evaluated for the aortic valve, the tricuspid valve, and the pulmonary valve. Using TEE, the appropriate size occluder was immersed in heparin saline solution and was screwed onto the delivery cable, and then placed into the upper sheath. An angiocatheter was passed into the right ventricle through the free wall of the right ventricle, and the needle was removed. A 0.035-inch glide wire was passed into the right ventricle through the angiocatheter and was then pulled out from the angiocatheter. The lower sheath was passed into the right ventricle through the wire, and then the wire was pulled out. With the help of TEE, the lower sheath was passed into the left ventricle through the VSD. The most important decision at operation is to choose the proper occluder size. Clinically, an imaging plane is selected so that the largest diameter is calculated. Usually the size of the occluder is the biggest diameter of VSD pulsing 2 to 4 mm, adjusting for the position of the aortic, pulmonary, and tricuspid valves, and the age of patient. For example, we choose as small as possible an occluder for infants. If the occluder is too big, the waist can not be naturally stretched, the discs of the left and right ventricle can not clamp the tissue of both ventricles, and the occlusion will fail. The upper sheath with the VSD occluder was screwed to the lower sheath, and the whole sheath was allowed to back bleed to ensure there was no air entrapment. The sheath was gently pulled back until the tip was in the left ventricle. Under echocardiographic guidance, the left disc was deployed; the sheath and the device were pulled back until the left disc approximated the ventricular septum (Fig 1). The device can be gently rotated if wanted to let the zero rim near the aortic valve ring when the zero-rim occluder is used (Fig 2). The waist and the right disc were deployed while maintaining fair traction on the delivery cable (Fig 3). The position of the device was checked whether there was a residual shunt; the aortic valve, tricuspid valve, and pulmonary valve were evaluated for valve insufficiency; and the device was released by rotating the delivery cable anticlockwise. The sheath and the delivery cable were pulled out of the right ventricle, and the pursestring suture on the right ventricle free wall was tied. The pericardium was closed, and a chest tube was placed in the mediastinum. The sternum was approximated with the help of sternal wires. The chest wall was closed in routine fashion. The patients were extubated on the operating table. The chest tube was removed the next morning. Aspirin (50 to 100 mg) was given to all of the patients for 3 months.
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Fig 1. Releasing the left side disk. Arrow shows the position of the occluder (the left side disc was released from the sheath).
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The size of the VSD and the size of the occluders are outlined in Table 2.
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Clinical Experience
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There was no 30-day hospital operative mortality, and all VSDs were occluded successfully using intraoperative TEE confirmation. No patient required an immediate open heart operation with extracorporeal perfusion. The occluder sizes ranged from 4 mm to 8 mm. The zero-rim occluders were used in 3 patients. In 1 patient the initial device had to be changed to a bigger one before it was released because of residual shunting. The occluder placement time was 8 to 45 minutes, and the total operative time ranged from 35 to 65 minutes. No occluder dislocated after operation. No atrioventricular block happened in any of the patients. No residual shunting was noted on TEE the first day after surgery. No patient required blood perfusion. Patients were ambulatory the first day after surgery and were discharged 1 to 2 days postoperatively.
All patients were followed-up with chest x-ray films and TEE 1 to 3 months after their respective operations. No residual shunting of the occluder was observed. The tricuspid valve, aortic valve, and pulmonary valve were all functioning normally. No atrioventricular block was observed in this series. All patients were clinically well and asymptomatic, and none were on any medications after 3 months.
Technical Issues
The key to successful occlusion of VSDs is that the sheath must pass through the VSDs, which are only several millimeters in diameter in most cases. Also, the TEE can only provide a two-dimensional image, not the three-dimensional image. We also found that using TEE should provide a great vessel view for when surgeons are trying to pass through the VSDs with the sheath. The surgeons should decide the position as to where to put the angiocatheter in place. In my opinion, I always feel the thrill on the right ventricular wall and then choose where the thrill is most strong to put in the angiocatheter.
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Comment
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Transcatheter closure of VSDs using the Amplatzer septal occluder has been well studied for several years [3–5].
The perventricular technique was introduced in 1997, and the first patient who underwent intraoperative device closure of a muscular VSD without CPB was reported by Amin and colleagues [6] in 1998. The success of this technique, when compared with that of previous attempts, lies in several factors. The first factor is that CPB is not used, and avoiding CPB might decrease postoperative morbidity and mortality [1, 2]. The second factor is that the device placement and residual shunt can be evaluated by means of echocardiography because the heart is beating during the procedure. The third factor is that the delivery sheath is malleable and small in size. The occlusion of VSDs through a small lower sternotomy has distinct advantages compared with the transcatheter route. These include a shorter entrance route, no age limit, the convenience to manipulate the stiff and straight sheath, the shorter time of intracardiac manipulation (usually within 20 minutes, and now we can even finish it in 5 minutes), and no x-ray film exposure (without angiography in operations) [5]. Periventricular technique is unlimited to patient’s age and the transcatheter technique is only suitable for patients older than 3 years of age because of vessel diameter.
The VSDs are among the most common congenital cardiac lesions, and hemodynamically symptomatic patients require closure earlier in infancy. These patients are failing to thrive because of congestive heart failure. Catheterization laboratory closure of the VSD in these patients is difficult, and this carries a high risk of complications because of large sheath size relative to patient size. The catheters are difficult to manipulate, which increases cardiac catheterization time, radiation, and risk of arrhythmia. The periventricular approach simplifies VSD closure. The potential complications of cardiac catheterization and fluoroscopy are avoided because the procedure is performed under echocardiographic guidance. The procedure is simplified because there are no acute turns of the catheter inside the heart. Because the procedure is performed on the beating heart, the procedure time is significantly reduced; the closure rate and integrity of the aortic valve are evaluated before the device is released. Postoperatively, these patients are expected to recover faster than patients who have undergone closure during CPB.
The wires and catheters used in the procedure are the usual catheters used during cardiac catheterizations in neonates and infants. Hence, the chance of injuring the cardiac valves or other structures is low. The risk of long-term problems with the aortic valve remains unknown. Long-term follow-up will be needed. We do not believe it to be a problem because the device does not encroach on the aortic valve.
An important aspect is releasing the occluder while the sheath is vertical to the ventricular septum. This can be performed precisely and quickly, even in VSDs just under the aortic valve. And therefore this allows occlusion of VSDs, which are under the aortic valve, and even no rims in 3 patients in this group, which are very difficult to occlude by transcatheter. We use a one sheath technique and the occluder is placed inside the sheath in advance, so once the sheath is inside the left ventricle, the occluder is released only once. In contrast, with the transcatheter closure, the catheter is not easy to pass through the VSDs, and it can be very difficult to release the occluder, thus using more time and often failing to occlude. This is more difficult with the interventional transcatheter approach. After the occluder is released, the best way to prevent it from dropping out of position is to pull and push it repeatedly. Because the sheath is stiff and the performing route is short, it is very easy to pull and push. Serious complications of dropping off have seldom occurred. If the occluder is easy to drop off when pulling and pushing, and the occluder size mismatch is ruled out, we advise enlarging the incision and repairing the VSD with CPB, although it did not happen until now.
The key of the periventricular VSD occlusion is that the sheath should pass through the VSD. It will be very difficult for beginners, because the VSDs are usually small in diameter and the blood flow is facing the sheath, which is also more difficult in perimembranous VSDs around which there are many other structures, such as tricuspid valve and its tendons, and also the inner ventricular cardiac muscle. However, in our experience, the excellent TEE and the sensitive finger feeling can solve this problem.
The procedure is done under TEE, which is clear and reliable, and does not affect the operative field. We can also adjust the TEE repeatedly to get the clearest view of the VSD. With the progress of echocardiographic machines, we believe that we can look forward to the three-dimensional view of the VSD, and the occlusion would then become easier. Also, TEE is free from x-ray film injury compared with angiography.
In this group, there were no major complications in this series. Complications related to the catheter-placed Amplatzer device has been reported by Carminati and colleagues [3–5]. In his series with 122 cases, the complication rate was 1.0% to 5.0%. The most common complications were heart block, device embolization, hemolysis, and occluder displacement, but all were very low in occurrence.
When accidents happened in operations, such as the occluder dropping off, we were able to manage it more quickly because the procedure was performed by a cardiac surgeon in the operating room, where it was safer.
When performing complex hybrid surgery, when the cardiac surgeon can finish all the procedures by himself, for example, the VSD can be occluded by a periventricular route first and then the left procedures can be finished by CPB. The cardiologists who previously performed transcatheter VSD occlusions were not needed any more in such cases. The entire procedure was simplified.
This study has some limitations. First, there are only 11 cases until now, and the other limitation is that the follow-up time is only near 1 year. However, theoretically we believe that the long-time follow-up results would be same as in the transcatheter route, because we use the same occluders, and the only difference is the performing route.
In summary, occlusion of a VSD through a small lower sternotomy is minimally invasive and safe. It is suitable for most VSDs of any position, as well as infants. It is cosmetic, and has excellent early and midterm results. It is unlimited to the age of the patient, and it would be part of a complex hybrid surgery [7]. I also believe that we can perform a periventricular technique VSD occlusion by robotic assistance or thoracoscopic method in the future [8].
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Disclosures and Freedom of Investigation
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This was a clinical study and no funds were needed. The technology was designed by the authors who had full control of the design of the study, methods used, outcome measurements, analysis of data, and production of the written report.
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Footnotes
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Disclaimer The Society of Thoracic Surgeons, the Southern Thoracic Surgical Association, and The Annals of Thoracic Surgery neither endorse nor discourage use of the new technology described in this article.
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References
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- Rose EA. Off-Pump coronary artery bypass surgery N Engl J Med 2003;348:379-380.[Free Full Text]
- Kern FH, Hicky PR. The effects of cardiopulmonary bypass on the brainIn: Jonas RA, editor. Cardiopulmonary bypass in neonates, infants and young children. 1st ed.. Boston: Blackwell Science; 1994. pp. 263-278.
- Carminati M, Butera G, Chessa M, Drago M, Negura D, Piazza L. Transcatheter closure of congenital ventricular septal defect with Amplatzer septal occluders Am J Cardiol 2005;19:9652L–8L.
- Moodie DS. Technology insight: transcatheter closure of ventricular septal defects Nat Clin Pract Cardiovasc Med 2005;2:592-596.[Medline]
- Zhang YS, Li H, Liu JP, et al. Complications of transcatheter interventional occlusion of ventricular septal defects Zhonghua Er Ke Za Zhi 2005;43:35-38.[Medline]
- Amin Z, Berry JM, Rocchini AL, Bass JL. Intraoperative closure of muscular ventricular septal defects in a canine model and application of the technique in a baby J Thorac Cardiovasc Surg 1998;115:1374-1376.[Free Full Text]
- Christian PB, Christian O, James LW. New approach to multiple ventricular septal defect closure with intraoperative echocardiography and double patches sandwiching the septum J Thorac Cardiovasc Surg 2004;128:684-692.[Abstract/Free Full Text]
- Amin Z, Russell Woo, David AD, et al. J Thorac Cardiovasc Surg 2006;131:427-432.[Abstract/Free Full Text]
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Abstract
Introduction
