Introduction
Hypoplastic left heart syndrome with right aortic arch is rare, and performing the Norwood procedure in these cases becomes challenging. Reference Patel, Bartlett, Scholz, Burzynski, Behrendt and Burkhart1,Reference Matsushima, Oshima and Matsuhisa2
Furthermore, coexisting chromosomal abnormalities or other associated congenital anomalies classify a patient as high-risk. Reference Rychik, Szwast and Natarajan3
Ductal stenting is a commonly performed procedure for high-risk hypoplastic left heart; however, there have been no reports of its use in patients with hypoplastic left heart syndrome and right aortic arch. Reference DiBardino, McElhinney, Marshall and Bacha4
Case
A 3-month-old boy was diagnosed with 20q11.2 microdeletion syndrome, hypoplastic left heart syndrome, and right aortic arch. Foetal ultrasonography revealed hypoplastic left heart syndrome and a vascular ring. At 37 weeks and 1 day of gestation, the baby was born without asphyxia and weighed 1793 g. Postnatal echocardiography and cardiac CT revealed hypoplastic left heart syndrome associated with a right aortic arch forming a vascular ring (Figure 1). Intravenous administration of prostaglandin E1 was initiated. Bilateral pulmonary artery banding was performed on Day 7. Due to frequent apnoea episodes, feeding difficulties, slender fingers, micrognathia, and CHD, chromosomal abnormalities were suspected. Chromosomal microarray analysis revealed microdeletions in the 4q13.1, 4q28, 2q28.3, 9p12–p11.2, and 20q11.22–q11.23 regions. Based on these findings, the patient was diagnosed with the 20q11.2 microdeletion syndrome. In addition, the patient exhibited right ventricular systolic dysfunction. Given the background of chromosomal abnormalities and cardiac dysfunction, arterial duct stenting was selected as a form of palliative care to avoid early infantile Norwood surgery and facilitate discharge to home.
A 3D cardiac CT showing hypoplastic left heart syndrome with a right aortic arch. ( a ) the whole heart from frontal view. ( b ) the left lateral view showing the main pulmonary artery, ductus arteriosus, and descending aorta. ( c )–( f ) the right aortic arch forming vascular ring. ( e ) the trachea and oesophagus was surrounded by ascending aorta, transverse arch, ductus arteriosus and main pulmonary artery. aAo = ascending aorta; DA = ductus arteriosus; dAo = descending aorta; eso = oesophagus; innV = innominate vein; LA = left atrium; LCCA = left common carotid artery; LPA = left pulmonary artery; LSCA = left subclavian artery; LVA = left vertebral artery; MPA = main pulmonary artery; RA = right atrium; RCCA = right common carotid artery; RPA = right pulmonary artery; RSCA = right subclavian artery; RV = right ventricle; SVC = supra vena cava; T = trachea.
The weight of the patient at the time of the procedure was 4.1 kg. Because the patient had impaired right ventricular function, direct sheath insertion into the main pulmonary artery was performed via sternotomy in a hybrid operating room. A 7 Fr sheath was inserted into the main pulmonary artery under direct visualisation. A 0.035-inch Radifocus guide wire was advanced through the arterial duct into the descending aorta, and the contrast material was injected through the sheath (Figure 2a). The arterial duct had a maximum diameter of 8.6 mm and a minimum diameter of 7.4 mm. An Omnilink Elite® (Abbot, Chicago, IL) stent with a diameter of 9 mm and a length of 19 mm was selected. The position was adjusted using fluoroscopy, and the stent was deployed at 11 atm. No complications were observed during the procedure, and the stent was placed without protruding into the arterial branches (Figure 2b).
Three months after the procedure, the patient was discharged with multiple medications for heart failure. However, the patient died two months after discharge because of circulatory failure caused by a viral infection.
Discussion
The patient presented with hypoplastic left heart syndrome and a right aortic arch associated with 20q11.2 microdeletion syndrome. The major features of the 20q11.2 microdeletion syndrome include intellectual disability, anomalies of the extremities, feeding difficulties, and craniofacial dysmorphism. Reference Jedraszak, Demeer and Mathieu-Dramard5 Although there have been reports of total anomalous pulmonary venous return in patients with this syndrome, the coexistence of complex CHD with single-ventricle physiology has not been previously reported, making this the first such case.
Known genetic abnormalities associated with syndromic hypoplastic left heart syndrome include deletions of 11q and 21q22.3, while non-syndromic abnormalities have been associated with mutations in genes such as NKX2-5 (5q35.1) and NOTCH1 (9q34.3). Reference Pierpont, Brueckner and Chung6 However, none of these known hypoplastic left heart-associated genetic alterations were identified in the present case. In addition, although this patient exhibited a rare cardiovascular phenotype of a right aortic arch, previously reported genetic abnormalities associated with this anomaly were also absent. Reference Zhang, Huang and Zhou7 Therefore, explaining the cardiovascular phenotype in this case based on currently known genetic factors remains difficult. Nonetheless, the genetic basis of hypoplastic left heart is considered complex and likely involves the interaction of multiple genetic variants. Reference McBride, Pignatelli and Lewin8,Reference Liu, Yagi and Saeed9 This patient harboured several microdeletions, and it is plausible that the combination of these deletions contributed to the development of the unique cardiovascular morphology observed in this case.
We performed ductal stenting in the patient. Although Norwood procedures for non-syndromic hypoplastic left heart syndrome with a right aortic arch have been previously reported and various surgical modifications have been described, the survival rate following Norwood surgery in high-risk patients, such as those with chromosomal abnormalities, remains significantly lower (56.5%) than that in the standard-risk group (92.8%). Reference Patel, Bartlett, Scholz, Burzynski, Behrendt and Burkhart1–Reference Rychik, Szwast and Natarajan3 Given that the patient had a chromosomal abnormality and impaired cardiac function, the case was considered high-risk for Norwood surgery.
Ductal stenting is an established palliative technique that serves as a bridge to cardiac transplantation or hybrid Stage I palliation. Reference DiBardino, McElhinney, Marshall and Bacha4 However, ductal stenting for a right aortic arch forming a vascular ring requires careful consideration of potential interference with the trachea and oesophagus. We evaluated the potential impact of ductal stenting on the oesophagus and trachea in this patient. Based on the CT imaging, the ductus arteriosus was found to be at some distance from both the trachea and oesophagus. Even after anticipated stent implantation, which would straighten the ductus arteriosus, a residual distance from the oesophagus was still expected. Therefore, we concluded that ductal stenting was an appropriate therapeutic option. Our management strategy at that time was that, if the patient’s clinical course remained favourable and somatic growth was achieved, and if symptoms of tracheal or oesophageal compression developed, surgical relief of the vascular ring would be undertaken. Since the morphology of the aortic arch varies among patients, individualised evaluation is required.
In this case, the procedure was performed under direct vision through a sternotomy with sheath insertion into the main pulmonary artery. This approach avoided passing a rigid sheath through the tricuspid valve, thereby preventing haemodynamic deterioration and allowing successful completion of the procedure.
In conclusion, we performed ductal stenting in a patient with 20q11.2 microdeletion syndrome complicated by hypoplastic left heart syndrome and a right aortic arch. Ductal stenting has proven to be a valuable therapeutic option even in cases where Norwood surgery is considered high-risk owing to the presence of hypoplastic left heart syndrome and a right aortic arch.
Angiographic findings during stent placement. ( a ) a 7 Fr short sheath was inserted into the main pulmonary artery under sternotomy for contrast injection. ( b ) the stent was placed without protruding to the descending aorta. DA = ductus arteriosus; dAo = descending aorta; LPA = left pulmonary artery; LSCA = left subclavian artery; MPA = main pulmonary artery.
Financial support
This research received no specific grants from any funding agency, commercial, or not-for-profit sectors.
Competing interests
None.
Ethical standard
The authors assert that all procedures contributing to this work comply with the ethical standards of the relevant national guidelines on human experimentation and the Helsinki Declaration of 1975, as revised in 2008. Informed consent for the publication of patient information was obtained from the patient’s caretaker.
