The thoracic cavity was first explored endoscopically by

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1 Video-Assisted Cardioscopy in Congenital Heart Operations Redmond P. Burke, MD, Guido Michielon, MD, and Gil Wernovsky, MD Departments of Cardiology and Cardiovascular Surgery, Children's Hospital, and Departments of Pediatrics and Surgery, Harvard Medical School, Boston, Massachusetts Recent advances in fiberoptics and endoscopic imaging technology have extended the applications of video assistance in surgical procedures. Video-assisted thoracoscopic surgical techniques have been employed to improve anatomic visualization within the pleural space and to reduce chest wall trauma. Open heart operations for congenital heart disease in neonates and infants also require clear visualization of small structures within confined spaces. By adapting pediatric thoracoscopic instrumentation, we have developed a technique for video-assisted cardioscopy, This technique was used in 4 patients with complex congenital heart disease to expose remote intracardiac structures and facilitate surgical repair. The patients ranged in weight from 4.6 to 17 kilograms, and visualization of the intended structures was achieved in each case within 12 minutes. There were no complications associated with the videoscope. Further experience with video-assisted cardioscopy might broaden its role as an adjunct to the surgical repair of complex congenital heart defects. (Ann Thome Surg ) The thoracic cavity was first explored endoscopically by [acobaeus in 1910 [I]. Since then, the development of compact fiberoptic scopes and video cameras has provided access to virtually every anatomic space, with excellent visualization of small structures. Technically successful video-assisted procedures in congenital heart operations include patent ductus arteriosus interruption [2] and vascular ring division [3]. Although long-term outcome studies have not yet been reported, these early investigations demonstrate the efficacy of video-assisted thoracic techniques in providing pediatric thoracic access and exposure, even in very low birthweight, premature newborns. Technological innovations in the staged management of complex congenital heart defects, such as transcatheter stents, septal occluder devices, and balloon dilators, while extending treatment options for difficult anatomic lesions, have also produced new surgical challenges. In this report, we describe our initial experience with endoscopic imaging techniques in pediatric open heart operations. Material and Methods Selected patients with congenital heart disease, referred for operation between May 1993 and January 1994, underwent video-assisted cardioscopy (VAC) as part of their open heart operations. Patients were selected for VAC if their cardiac anatomy, or the presence of intracardiac devices, presented potentially difficult operative exposure, as determined by preoperative echocardiography or catheterization, or based on intraoperative findings. Patients were excluded if adequate exposure could be achieved with conventional surgical techniques. Patient charts, operative Accepted for publication May 13, Address reprint requests to Dr Burke, Department of Cardiac Surgery, Children's Hospital, 300 Longwood Ave, Boston, MA by The Society of Thoracic Surgeons reports, and perfusion records were reviewed retrospectively, and reports were obtained from the referring cardiologists. Data included age and weight at operation, cardiac anatomy, duration of VAC, cardiopulmonary bypass times, operative results, morbidity, and mortality. All patients undergoing VAC are included in this report, and the procedures were performed by one surgeon (R.P.B.). Patient characteristics are presented in Table 1. In patients 1, 3, and 4, VAC was planned preoperatively, based on catheterization and echocardiography suggesting difficult operative exposure. In patient 2, intraoperative findings prompted VAC. Pediatric VAC was performed with the same equipment used in pediatric video-assisted thoracic operations. Videoscopes (Smith and Nephew, Dyonics, Inc, Andover, MA) were chosen based on size (either 2.7 mm or 4 mm diameter with a 7-cm working length) and the angle at the camera face (30 or 70 degrees) and produced 4X magnification. Endoscopic instruments were not required. In cases where VAC was planned preoperatively, the video equipment was on the operative field before cardiopulmonary bypass was initiated. The videoscope path taken to achieve exposure was unique to each case, determined by the cardiac anatomy and the structures being visualized. The paths were planned to minimize additional cardiac incisions, operative field obstruction, and cardiac distortion. A blood-free operative field was necessary for optimal VAC visualization. This was accomplished on bypass, by venting the left ventricle or by using hypothermic circulatory arrest. Continuous intracardiac irrigation to clear the field was not required. The videoscope was advanced by the surgeon under direct vision, and its position was maintained by the first assistant /94/$7.00

2 Ann Thorac Surg BURKE ET AL 865 Table 1. Video-Assisted Cardioscopy in Congenital Heart Operation: Patient Characteristics Weight Patient Age (kg) Anatomic Diagnosis Indication for VAC Videoscope Path 1 (planned VAC) 6 mo 5.5 Conoventricular VSD; Visualize device position muscular VSDin mid- and assess MV RA to VSD to LV apparatus sip transvenous clamshell placement 2 (unplanned VAC) 4.5 Y 17 DORVIPS; laa type B Visualize laceration of anterior MV leaflet, RA to ASD to LV sip transcatheter stenting of restrictive VSD 3 (planned VAC) 7mo 4.8 CAVC; Muscular VSDs in mid- and apical Locate muscular VSD RA to ASD to LV 4 (planned VAC) 7mo 8.6 Muscular VSD in mid- Locate muscular VSD Aorta to LV and RA to VSD to LV Outcome no residual VSD, died 7 months postop of RSV pneumonia minimalmr, stable at 7-month Missed apical VSD, residual VSD required PAB, stable at I-month no residual VSD, well at 1 month ASD = atrial septal defect; CAVC = complete atrioventricular canal; DORV IPS = double outlet right ventricle/pulmonary stenosis; IAA = interrupted aortic arch; LV = left ventricle; MR = mitral regurgitation; MV = mitral valve; PAB = pulmonary artery band; RA = right atrium; RSV ~respiratory syncytial virus; sip = status post; VAC = video-assisted cardioscopy; VSD = ventricular septal defect. Results From May 1993 to January 1994, 4 patients underwent VAC during open heart operation. The patients ranged in age from 6 months to 4.6 years and in weight from 4.6 to 17 kg. Video-assisted cardioscopy allowed visualization of the intended cardiac structures in all cases and was effective during both cardiopulmonary bypass and hypothermic circulatory arrest. The time to achieve videoscope preparation, insertion, and exposure ranged from 3 to 12 minutes. There were no operative deaths. One patient had a residual apical muscular ventricular septal defect which was not detected by VAC. No other complications were associated with use of the videoscope. The cases are presented chronologically. Patient 1 A 5.5-kg child was in congestive heart failure with failure to thrive at 6 months of age. Echocardiography and cardiac catheterization demonstrated a large conoventricular, and multiple midmuscular ventricular septal defects (VSDs). The pulmonary to systemic flow ratio was greater than 4, and pulmonary artery pressure was systemic. Due to the complex nature of the multiple septal defects, the patient underwent a preoperative interventional cardiac catheterization to close the midmuscular VSD, thereby limiting the planned operation to closure of the conoventricular defect [4]. During the preoperative catheterization, a 23-mm Bard clamshell septal occluder (Bard, Billerica, MA) was positioned in the midmuscular VSD, but two of the right ventricular arms prolapsed through the defect into the left ventricle and appeared to entrap the sub-valvar mitral apparatus. The patient was prepared for surgical closure of the membranous ventricular septal defect, and VAC was planned to inspect the prolapsed right ventricular arms of the clamshell and visualize the sub-mitral valvar apparatus. Under deep hypothermia and circulatory arrest, a right atriotomy was made and the videoscope (4-mm diameter, 70-degree face angle) was advanced through the conoventricular VSD and into the left ventricle (Fig 1). The subvalvar mitral apparatus and the clamshell device were examined, and the prolapsed arms were well-seen. Using forceps, the arms were repositioned from the right ventricular side and the device position on the left side was confirmed with the videoscope. The mitral valve apparatus was clearly seen, and was not entrapped by the clamshell. Videoscope insertion and cardioscopy were completed in 10 minutes. The conoventricular VSD was then closed with a Dacron patch, and the atrial septal defect was closed primarily. The patient was separated from cardiopulmonary bypass after a total perfusion time of 1 minute, 57 seconds, a cross-clamp time of 55 minutes, and a circulatory arrest time of 53 minutes. Postoperative echocardiography showed no apparent mitral insufficiency or residual VSD. There were no complications, and the patient was discharged on postoperative day 9, doing well. Although the patient was clinically improved at her 1-month followup, with no residual ventricular septal defect by echocardiography, she died of respiratory failure secondary to a respiratory syncytial virus pneumonia 7 months after discharge. Patient 2 A 4.5-year-old, 17-kg boy presented with cyanosis at birth and was diagnosed by echocardiography and catheterization with {S,D,D} segmental cardiac anatomy, a complex conotruncal malformation (resembling double outlet right ventricle with a subpulmonary ventricular septal defect),

3 866 BURKE ET AL Ann Thorac Surg 1994;58:864-8 Fig 1. (Patient 1.) Rigllt atrial exposure of the ucniricular with the nidcoscopc advanced through the conoocniriculardefect into the left ventricle. (Inset) Four-chamber view of the videoscope within the left ventricular cavitlj visualizing the clamshelldevice in the muscular septal defect. and an interrupted aortic arch. He underwent repair of the interrupted arch and pulmonary artery banding as a neonate. He subsequently underwent a bidirectional cavopulmonary anastomosis and further banding of the pulmonary artery at 2 years of age at another institution. Progressive restriction of the VSD resulted in suprasystemic left ventricular pressure and left ventricular failure. He was considered inoperable at his home institution, and was referred to Children's Hospital for further management. Transvenous dilation and stenting of the restrictive VSD was performed by passing a catheter from the inferior vena cava, across the atrial, through the mitral valve, and into the VSD. During the procedure, the anterior leaflet of the mitral valve was lacerated by the stiff guide wire, causing severe mitral regurgitation. The pa- tient was intubated and required inotropic support before urgent operation. The need for VAC was not anticipated in this case. The heart was exposed by a median sternotomy. Leftward juxtaposition of the atrial appendages and mesocardia hindered atrial access. Cardiopulmonary bypass was achieved using bicaval cannulation, and under moderate hypothermia and cardioplegic arrest, a right atriotomy incision was made. Transatrial mitral valve exposure was difficult due to the mesorotation and a diminutive left atrium. Preparations were made for VAC while further Fig 2. (Patient 2,) Video-assisted image of a lacerated anterior mitral valve leaflet. Fig 3. (Patient 2.) Video-assisted mitral valvuloplasty.

4 Ann Thorae Surg BURKE ET AL VlDEO-ASSISTED CARDlOSCOPY 867 efforts were made to improve the exposure by enlarging the atrial septal defect. A 4-mm-diameter, 30-degreeangled videoscope was advanced through the right atriotomy and across the atrial septal defect to assess the mitral valve. The total time to achieve intracardiac visualization was 12 minutes, including equipment setup time. The subvalvar apparatus was clearly visualized and found to be intact. A laceration was found extending from the midportion of the anterior leaflet to the annulus (Fig 2). While the first assistant maintained videoscope position, the laceration was repaired with interrupted Prolene (Ethicon, Somerville, NJ) sutures (Fig 3). Valve competency was confirmed by injecting saline solution into the left ventricle under VAC visualization. The patient separated from bypass without difficulty after a total bypass time of 2 minutes, 29 seconds and a cross-clamp time of 1 minute, 44 seconds. Intraoperative transesophageal echocardiography showed mild residual mitral regurgitation and minimal mitral stenosis. The patient was discharged home on postoperative day 17, with echocardiography showing improved left ventricular function. On examination at 6 months postoperatively, the child was doing well, with repeat echocardiography showing mild mitral regurgitation. Patient 3 A 7-month-old, 4.8-kg patient presented in utero with fetal bradycardia, and echocardiography at birth showed heterotaxy (polysplenia) with a transitional atrioventricular canal, an interrupted inferior vena cava with azygous continuation to the right superior vena cava, and a persistent left superior vena cava draining to the coronary sinus. Poorly compensated congestive heart failure led to surgical referral, and preoperative echocardiography demonstrated an additional muscular ventricular septal defect with a single orifice on the left ventricular side and multiple exit points on the right ventricular side. Electrophysiologic testing revealed prolonged sinus node recovery time and abnormal atrioventricular node function, and at cardiac catheterization the pulmonary artery pressure was systemic. A complete operative repair was planned, including surgical closure of the muscular VSD. The Bard septal occluder was not approved by the Food and Drug Administration at the time of this child's operation, and VAC was planned to facilitate the surgical repair. Through a right atriotomy, a 4-mm-diameter, 70-degreeangled videoscope was advanced through the atrioventricular canal into the left ventricular cavity. The time from videoscope insertion to VSD visualization was 3 minutes. Despite unexpected trabeculations on the left ventricular septal surface, a single 3-mm orifice was found in the midmuscular. To minimize the circulatory arrest time, no further exploration was performed. Under video guidance, a pledgeted mattress suture was placed from the right ventricular side. By visualizing the needle passing through the on the left ventricular side, the VSD was encircled by the suture and closed. The videoscope was removed, and the atrioventricular canal was then repaired with a single pericardiai patch. The left superior vena cava was baffled across the roof of the left atrium to the right atrium with a Gore-Tex (W. L. Gore & Assoc) patch. The patient was separated from bypass after a total bypass time of 4 minutes, 12 seconds, a cross-clamp time of 2 minutes, 12 seconds, and a circulatory arrest time of 57 minutes. Intraoperative measurements of right atrial and pulmonary artery oxygen saturations suggested no hemodynamically significant residual VSD. Three days postoperatively, the patient had a step-up in the right atrial to pulmonary artery saturations suggesting a pulmonary to systemic flow ratio of 2:1, and cardiac catheterization demonstrated a previously undiagnosed muscular defect in the apical portion of the. The patient was extubated on the eighth postoperative day, but persistent failure to thrive and episodes of junctional rhythm prompted reoperation for pulmonary artery banding and epicardial pacemaker insertion. The patient was eventually discharged after 4 months in the hospital, and at I-month was improving at home, with appropriate weight gain. Patient 4 A 7-month-old, 8.6-kg boy was diagnosed with a complex midmuscular VSD. The defect measured 10 by 7 mm, and the right ventricular orifice of the VSD appeared to be partially covered by the moderator band. There was echocardiographic evidence of pulmonary hypertension and the patient was referred for operation. Video-assisted cardioscopy was planned to facilitate exposure of the VSD. Cardiopulmonary bypass was achieved with bicaval cannulation, the patient was cooled to 25 C, and the aorta was clamped. Cardioplegia was given through the aortic root, and the left ventricle was vented through the right superior pulmonary vein. Right atriotomy exposed the right ventricular septal surface and the moderator band was divided. The muscular defect was not visible; therefore, a 4-mm aortotomy was made adjacent to the cardioplegia site and was controlled with a pursestring. The 4-mm, 30-degree-angled videoscope was advanced into the aortic root. Under direct vision on the video monitor, the scope was advanced into the left ventricle and the was explored. The camera angle was insufficient to visualize the apical, and the videoscope was removed from the aorta and redirected through the right atriotomy into the right ventricle. The septal defect was discovered in the mid-apical, and the scope was advanced through the defect into the left ventricle. A fibrous rim was apparent on the left ventricular side of the defect, and no additional defects were seen. Circumferential horizontal mattress sutures were placed, and a Dacron patch was used to close the defect. Video-assisted cardioscopy time was 11 minutes, total cardiopulmonary time was 2 minutes, 14 seconds, and the crossclamp time was 88 minutes. Intraoperative transesophageal echocardiography showed no residual VSD and normal aortic valve function. There was no arterial oxygen saturation step-up from the right atrium to the pulmonary artery. Postoperatively, the patient had labile pulmonary hypertension, frequently approaching systemic levels. There was echocardiographic evidence of moderate ventricular dysfunction, and the left atrial pressures in the intensive care

5 868 BURKE ET AL Ann Thorae Surg unit ranged from 12 to 19 mm Hg over the first 24 postoperative hours. The patient was kept on continuous neuromuscular blockade and sedation with Fentanyl for 72 hours postoperatively. His labile pulmonary hypertension and ventricular dysfunction resolved, and he was successfully extubated on the fifth postoperative day. He had an uncomplicated subsequent postoperative course, was discharged 11 days after operation, and was doing well at 1-month. Comment A multimodality approach to the treatment of complex congenital heart defects in neonates, combining complete anatomic surgical repair with interventional cardiology techniques, has benefited from technological advances, while producing some complex therapeutic challenges. Experience with endoscopic techniques for patent ductus arteriosus interruption and vascular ring division in neonates led us to consider using video assistance during congenital open heart operations when difficult anatomic situations were anticipated preoperatively or encountered intraoperatively. Video-assisted cardioscopy allows visualization and magnification of inaccessible structures while avoiding vigorous cardiac manipulation and extended incisions. Video assistance might facilitate closure of muscular ventricular septal defects where surgical results using right atrial exposure have been frustrating [5]. Left ventriculotomy to improve exposure has produced an unacceptable incidence of ventricular dysfunction, arrhythmias, and aneurysm formation [6]. To surmount these problems, a collaborative approach using interventional cardiology techniques and operation has been adopted. Preoperative clamshell device placement has been performed in selected patients, with variable success [4]. As in patient 1, VAC can be used to reposition devices and to confirm safe seating against the left ventricular side of the. Intraoperative clamshell device placement has also been described [7], but has been partially limited by the surgeon's inability to visualize the left ventricular cavity while inserting the device. Video-assisted cardioscopy could be used to guide advancement of the introducer catheter and to confirm secure device opening and seating, increasing the precision of an otherwise blind technique. Other potential VAC applications include imaging of left ventricular outflow tract obstruction and localization of residual defects after VSD repair. Residual interventricular defects after repair of conotruncal malformations have been difficult to localize by either catheterization or echocardiography, and consequently, surgical results have been poor [8]. Passing the videoscope through the aortic root into the left ventricle could produce a magnified image of a defect in the patch margin from the left side. Transillumination from the videoscope could localize the defect on the right ventricular side as viewed through the right atrium and guide suture placement while ensuring that the aortic valve is not jeopardized. Potential problems with VAC include prolonged cardiopulmonary bypass or circulatory arrest times, valve laceration, ventricular or atrial wall perforation, and conduction system contusion. To prevent trauma, the rigid videoscope must be advanced along a straight anatomic path, avoiding cardiac distortion. As with other endoscopic techniques, success depends on appropriate instrumentation and a clear operative strategy. This is crucial when using VAC during circulatory arrest, when time constraints are more severe. Ironically, concern about prolonging circulatory arrest may have contributed to our failure to identify the additional apical muscular defects in Case 2, resulting in a significant residual defect and prolonged hospitalization. Our preliminary experience with VAC is insufficient to demonstrate improved surgical outcome, but it confirms the technical feasibility of imaging small, inaccessible structures during repair of complex congenital heart defects. The cases presented here also demonstrate the ability of VAC to locate muscular ventricular septal defects and to guide intracardiac transcatheter device manipulation. These preliminary results do not justify routine VAC during congenital heart operations; however, in selected cases, the technique can provide atraumatic intracardiac visualization. Further experience with VAC might broaden its clinical applicability. We thank Aldo R. Castaneda, MD, and James E. Lock, MD, for their support and review of this work. References 1. Jacobaeus H. Possibility of the use of cystoscopy for investigation of serious cavities. Munch Med Wochenschr 1910;57: Laborde F, Noirhomme P, Karam J, Batisse A, Bourel P, Saint Maurice O. A new video-assisted thoracoscopic surgical technique for interruption of patent ductus arteriosus in infants and children. J Thorac Cardiovasc Surg 1993;105: Burke R, Chang A. Video-assisted thoracoscopic division of a vascular ring in an infant: a new operative technique. J Card Surg 1993;8: Bridges ND, Perry SB, Keane JF, et al. Preoperative transcatheter closure of congenital muscular ventricular septal defects. N EngI J Med 1991;324: Kirklin J, Castaneda A, Keane J, Fellows K, Norwood W. Surgical management of multiple ventricular septal defects. J Thorac Cardiovasc Surg 1980;80: Hanna B, Colan S, Bridges N, Mayer J, Castaneda A. Clinical and myocardial status after left ventriculotomy for ventricular septal defect closure. J Am CoIl Cardiol 1991;17(Suppl):110A. 7. Fishberger S, Bridges N, Keane J, et al. Intraoperative device closure of ventricular septal defects. Circulation 1993;88(Part 2): Preminger T, Sanders S, van der Velde M, Castaneda A, LockJ. "Intramural" residual interventricular defects after repair of conotruncal malformations. Circulation 1994;89: