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Case Study
Repair of unbalanced atrioventricular septal defect with small right ventricle
Asian Cardiovascular & Thoracic Annals 0(0) 1–3 ß The Author(s) 2014 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav DOI: 10.1177/0218492314546029 aan.sagepub.com
Yoshihiro Oshima, Ayako Maruo, Tomomi Hasegawa and Hironori Matsuhisa
Abstract A 2-month-old boy with trisomy 21, a small right ventricle, and an unbalanced atrioventricular septal defect underwent successful biventricular repair without atrial fenestration. We decided to perform leftward partitioning of the atrioventricular valve to widen the right ventricle inflow tract. This procedure increases the size of the right-sided valve and allows full function of the right ventricle without an atrial communication. This technique should be employed in patients with a small right ventricle and an unbalanced atrioventricular septal defect, as an alternative to atrial septal fenestration or univentricular palliation.
Keywords Cardiac surgical procedures, Down syndrome, Heart defects, Congenital, Heart septal defects, Heart ventricles, Infant
Introduction It is still difficult to determine whether to employ biventricular repair (BVR) or univentricular palliation for a hypoplastic left ventricle (LV) or right ventricle (RV). Because most patients with unbalanced atrioventricular (AV) septal defect and a small RV have trisomy 21, use of univentricular palliation may be suboptimal. Rather, an aggressive strategy for biventricular repair is often required in patients with increased pulmonary vascular resistance. For patients with a hypoplastic RV, an adjustable atrial fenestration has been proposed to extend the limits for BVR.1 Instead of atrial fenestration, we decided to perform leftward partitioning of the AV valve to widen the RV inflow tract in BVR. This study was approved by the ethics committee of Kobe Children’s Hospital as a retrospective chart analysis. The committee waived the need for patient consent.
with mild AV valve regurgitation. The right-sided AV valve and right ventricle were hypoplastic. The ratio of the two valve areas (AV valve index) was 0.42.2 The right AV valve-to-total AV valve ratio was 0.30. The RV-to-LV length ratio was 0.67 (Figure 1). Catheterization indicated balanced pulmonary and systemic arterial pressures, and pulmonary vascular resistance was 3.3 Wood units. The LV end-diastolic volume index was 102 mL m 2 and the RV end-diastolic volume index was 31 mL m 2. The operation was performed under cardiopulmonary bypass with bicaval cannulation and moderate hypothermia. A two-patch method was utilized to correct the anomaly. The septal defect was closed with a 0.4-mm expanded polytetrafluoroethylene patch. The bridging left superior leaflet was incised partially laterally to the valve annulus to expose the subaortic area, and the septal defect was closed with continuous 5/0 polypropylene sutures.
Case report A 2-month-old boy with Down’s syndrome was admitted to our hospital because of tachypnea. Echocardiography showed a left-dominant unbalanced AV septal defect with a large interatrial and interventricular communication, marked bridging of the left superior leaflet, and straddling of the right AV valve
Department of Cardiovascular Surgery, Kobe Children’s Hospital, Kobe, Japan Corresponding author: Yoshihiro Oshima, Department of Cardiovascular Surgery, Kobe Children’s Hospital, 1-1-1 Takakura-dai, Suma-ku, Kobe 654-0081, Japan. Email: [email protected]
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Asian Cardiovascular & Thoracic Annals 0(0)
Figure 1. Echocardiographic views. (A) Preoperative apical 4-chamber views demonstrating findings compatible with a left-dominant unbalanced atrioventricular septal defect with a large interatrial and interventricular communication, marked bridging of the left superior leaflet, and straddling of the right atrioventricular valve with mild atrioventricular valve regurgitation. (B) The right-sided atrioventricular valve and right ventricle were hypoplastic. The atrioventricular valve index was 0.42. The right atrioventricular valveto-total atrioventricular valve ratio was 0.30. The right ventricular-to-left ventricular length ratio was 0.67.
Figure 2. Schematic presentation of apical 4-chamber views, the surgeon’s view of the intraoperative findings, and the surgical technique applied in the patient. (A) Preoperative apical 4-chamber view: a left-dominant unbalanced atrioventricular septal defect with a large interatrial and interventricular communication is present. (B) Preoperative surgeon’s view: marked bridging of the left superior leaflet and straddling of the right atrioventricular valve is present. The dotted line shows leftward partitioning of the atrioventricular valve. (C) Postoperative apical 4-chamber view.
To shift the ventricular patch leftward, the accessory chordae from the left-sided leaflets on the crest or the right-sided straddling chordae from LV were divided in the new RV (Figure 2), and the conal septum was excised before an LV-to-aorta baffle was constructed. The mitral cleft was not closed to prevent stenosis of the orifice. The superior and inferior portions of the right-sided leaflets were sutured to the patch to prevent right-sided valve regurgitation. An autologous pericardial patch was sutured to the base of the left-sided valve tissue, leaving the coronary sinus to drain into the right atrium. On intraoperative direct echocardiography, there was no significant left- or right-sided AV valve stenosis or regurgitation. The postoperative course was uneventful. At the 55-month follow-up, the patient was clinically healthy. On the most recent echocardiographic assessment, the diameters of mitral and tricuspid valve were 16.9 mm (97% of normal) and 18.1 mm
(89% of normal), respectively, with no significant stenosis or regurgitation.
Discussion Biventricular repair for AV septal defect with a small RV is technically challenging. Patients with any probability of residual pulmonary artery hypertension and increased pulmonary vascular resistance may be considered as having a relative contraindication to oneand-a-half ventricle repair. Although a BVR with atrial septal fenestration might be a better option, postoperative oxygen desaturation must be accepted. While rightward or leftward partitioning of the AV valve may be the best choice in biventricular repair for unbalanced AV septal defect, outcomes regarding postoperative valve function and growth are unclear. Recent studies have described the growth potential of the AV valve
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after repartition of the AV valve in the context of a leftdominant AV septal defect.3 Because an unbalanced AV septal defect with a small RV is less common than with a small LV, repartition of the AV valve is rarely performed and is often associated with atrial fenestration.1,3 In this case, partitioning of the AV valve without atrial septal fenestration in a patient with a small RV resulted in acceptable mitral and tricuspid valve function and growth in the intermediate term. De Oliveira and colleagues1 proposed the use of an adjustable atrial fenestration to extend the limits for BVR in patients with a left-dominant AV septal defect. Elevated central venous pressure and the occurrence of oxygen desaturation are common in the acute or subacute postoperative phase. They also expressed some caution regarding the utilization of an aggressive strategy for BVR in cases with an AV valve index of less than 0.50. In contrast, leftward partitioning of the AV valve increases the size of the right-sided AV valve and leads to full function of the RV without an atrial communication. In failed cases with moderate to severe tricuspid stenosis, we have to choose atrial fenestration instead of a Glenn anastomosis because of high pulmonary vascular resistance; then home oxygen therapy for cyanosis would be required. We recommend that the technique used in this case should be employed for patients with a
small RV and an unbalanced AV septal defect, as an alternative to atrial septal fenestration or univentricular palliation. Funding This research received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors.
Conflict of interest statement None declared.
References 1. De Oliveira NC, Sittiwangkul R, McCrindle BW, et al. Biventricular repair in children with atrioventricular septal defects and a small right ventricle: anatomic and surgical considerations. J Thorac Cardiovasc Surg 2005; 130: 250–257. 2. Szwast AL, Marino BS, Rychik J, Gaynor JW, Spray TL and Cohen MS. Usefulness of left ventricular inflow index to predict successful biventricular repair in right-dominant unbalanced atrioventricular canal. Am J Cardiol 2011; 107: 103–109. 3. Foker JE, Berry JM, Harvey BA and Pyles LA. Mitral and tricuspid valve repair and growth in unbalanced atrial ventricular canal defects. J Thorac Cardiovasc Surg 2012; 143: S29–S32.
Downloaded from aan.sagepub.com at UNIV OF FLORIDA Smathers Libraries on November 15, 2015
(AAN)
[1–3] [PREPRINTER stage]
Case Study
Repair of unbalanced atrioventricular septal defect with small right ventricle
Asian Cardiovascular & Thoracic Annals 0(0) 1–3 ß The Author(s) 2014 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav DOI: 10.1177/0218492314546029 aan.sagepub.com
Yoshihiro Oshima, Ayako Maruo, Tomomi Hasegawa and Hironori Matsuhisa
Abstract A 2-month-old boy with trisomy 21, a small right ventricle, and an unbalanced atrioventricular septal defect underwent successful biventricular repair without atrial fenestration. We decided to perform leftward partitioning of the atrioventricular valve to widen the right ventricle inflow tract. This procedure increases the size of the right-sided valve and allows full function of the right ventricle without an atrial communication. This technique should be employed in patients with a small right ventricle and an unbalanced atrioventricular septal defect, as an alternative to atrial septal fenestration or univentricular palliation.
Keywords Cardiac surgical procedures, Down syndrome, Heart defects, Congenital, Heart septal defects, Heart ventricles, Infant
Introduction It is still difficult to determine whether to employ biventricular repair (BVR) or univentricular palliation for a hypoplastic left ventricle (LV) or right ventricle (RV). Because most patients with unbalanced atrioventricular (AV) septal defect and a small RV have trisomy 21, use of univentricular palliation may be suboptimal. Rather, an aggressive strategy for biventricular repair is often required in patients with increased pulmonary vascular resistance. For patients with a hypoplastic RV, an adjustable atrial fenestration has been proposed to extend the limits for BVR.1 Instead of atrial fenestration, we decided to perform leftward partitioning of the AV valve to widen the RV inflow tract in BVR. This study was approved by the ethics committee of Kobe Children’s Hospital as a retrospective chart analysis. The committee waived the need for patient consent.
with mild AV valve regurgitation. The right-sided AV valve and right ventricle were hypoplastic. The ratio of the two valve areas (AV valve index) was 0.42.2 The right AV valve-to-total AV valve ratio was 0.30. The RV-to-LV length ratio was 0.67 (Figure 1). Catheterization indicated balanced pulmonary and systemic arterial pressures, and pulmonary vascular resistance was 3.3 Wood units. The LV end-diastolic volume index was 102 mL m 2 and the RV end-diastolic volume index was 31 mL m 2. The operation was performed under cardiopulmonary bypass with bicaval cannulation and moderate hypothermia. A two-patch method was utilized to correct the anomaly. The septal defect was closed with a 0.4-mm expanded polytetrafluoroethylene patch. The bridging left superior leaflet was incised partially laterally to the valve annulus to expose the subaortic area, and the septal defect was closed with continuous 5/0 polypropylene sutures.
Case report A 2-month-old boy with Down’s syndrome was admitted to our hospital because of tachypnea. Echocardiography showed a left-dominant unbalanced AV septal defect with a large interatrial and interventricular communication, marked bridging of the left superior leaflet, and straddling of the right AV valve
Department of Cardiovascular Surgery, Kobe Children’s Hospital, Kobe, Japan Corresponding author: Yoshihiro Oshima, Department of Cardiovascular Surgery, Kobe Children’s Hospital, 1-1-1 Takakura-dai, Suma-ku, Kobe 654-0081, Japan. Email: [email protected]
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Asian Cardiovascular & Thoracic Annals 0(0)
Figure 1. Echocardiographic views. (A) Preoperative apical 4-chamber views demonstrating findings compatible with a left-dominant unbalanced atrioventricular septal defect with a large interatrial and interventricular communication, marked bridging of the left superior leaflet, and straddling of the right atrioventricular valve with mild atrioventricular valve regurgitation. (B) The right-sided atrioventricular valve and right ventricle were hypoplastic. The atrioventricular valve index was 0.42. The right atrioventricular valveto-total atrioventricular valve ratio was 0.30. The right ventricular-to-left ventricular length ratio was 0.67.
Figure 2. Schematic presentation of apical 4-chamber views, the surgeon’s view of the intraoperative findings, and the surgical technique applied in the patient. (A) Preoperative apical 4-chamber view: a left-dominant unbalanced atrioventricular septal defect with a large interatrial and interventricular communication is present. (B) Preoperative surgeon’s view: marked bridging of the left superior leaflet and straddling of the right atrioventricular valve is present. The dotted line shows leftward partitioning of the atrioventricular valve. (C) Postoperative apical 4-chamber view.
To shift the ventricular patch leftward, the accessory chordae from the left-sided leaflets on the crest or the right-sided straddling chordae from LV were divided in the new RV (Figure 2), and the conal septum was excised before an LV-to-aorta baffle was constructed. The mitral cleft was not closed to prevent stenosis of the orifice. The superior and inferior portions of the right-sided leaflets were sutured to the patch to prevent right-sided valve regurgitation. An autologous pericardial patch was sutured to the base of the left-sided valve tissue, leaving the coronary sinus to drain into the right atrium. On intraoperative direct echocardiography, there was no significant left- or right-sided AV valve stenosis or regurgitation. The postoperative course was uneventful. At the 55-month follow-up, the patient was clinically healthy. On the most recent echocardiographic assessment, the diameters of mitral and tricuspid valve were 16.9 mm (97% of normal) and 18.1 mm
(89% of normal), respectively, with no significant stenosis or regurgitation.
Discussion Biventricular repair for AV septal defect with a small RV is technically challenging. Patients with any probability of residual pulmonary artery hypertension and increased pulmonary vascular resistance may be considered as having a relative contraindication to oneand-a-half ventricle repair. Although a BVR with atrial septal fenestration might be a better option, postoperative oxygen desaturation must be accepted. While rightward or leftward partitioning of the AV valve may be the best choice in biventricular repair for unbalanced AV septal defect, outcomes regarding postoperative valve function and growth are unclear. Recent studies have described the growth potential of the AV valve
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after repartition of the AV valve in the context of a leftdominant AV septal defect.3 Because an unbalanced AV septal defect with a small RV is less common than with a small LV, repartition of the AV valve is rarely performed and is often associated with atrial fenestration.1,3 In this case, partitioning of the AV valve without atrial septal fenestration in a patient with a small RV resulted in acceptable mitral and tricuspid valve function and growth in the intermediate term. De Oliveira and colleagues1 proposed the use of an adjustable atrial fenestration to extend the limits for BVR in patients with a left-dominant AV septal defect. Elevated central venous pressure and the occurrence of oxygen desaturation are common in the acute or subacute postoperative phase. They also expressed some caution regarding the utilization of an aggressive strategy for BVR in cases with an AV valve index of less than 0.50. In contrast, leftward partitioning of the AV valve increases the size of the right-sided AV valve and leads to full function of the RV without an atrial communication. In failed cases with moderate to severe tricuspid stenosis, we have to choose atrial fenestration instead of a Glenn anastomosis because of high pulmonary vascular resistance; then home oxygen therapy for cyanosis would be required. We recommend that the technique used in this case should be employed for patients with a
small RV and an unbalanced AV septal defect, as an alternative to atrial septal fenestration or univentricular palliation. Funding This research received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors.
Conflict of interest statement None declared.
References 1. De Oliveira NC, Sittiwangkul R, McCrindle BW, et al. Biventricular repair in children with atrioventricular septal defects and a small right ventricle: anatomic and surgical considerations. J Thorac Cardiovasc Surg 2005; 130: 250–257. 2. Szwast AL, Marino BS, Rychik J, Gaynor JW, Spray TL and Cohen MS. Usefulness of left ventricular inflow index to predict successful biventricular repair in right-dominant unbalanced atrioventricular canal. Am J Cardiol 2011; 107: 103–109. 3. Foker JE, Berry JM, Harvey BA and Pyles LA. Mitral and tricuspid valve repair and growth in unbalanced atrial ventricular canal defects. J Thorac Cardiovasc Surg 2012; 143: S29–S32.
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