Clinical Anatomy 23:950–955 (2010)
ORIGINAL COMMUNICATION
Anomalous Subaortic Left Brachiocephalic Vein in Surgical Cases and Literature Review MITSUGI NAGASHIMA,1* FUMIAKI SHIKATA,1 TORU OKAMURA,1 EIICHI YAMAMOTO,2 TAKASHI HIGAKI,2 MASASHI KAWAMURA,1 MASAHIRO RYUGO,1 HIRONORI IZUTANI,1 HIROSHI IMAGAWA,1 SHUNJI UCHITA,3 YOSHITAKA OKAMURA,3 HIROYUKI SUZUKI,4 YOSHITSUGU NAKAMURA,5 OSAMU TAGUSARI,5 AND KANJI KAWACHI1 1
Department of Cardiothoracic Surgery, Ehime University School of Medicine, Ehime, Japan 2 Department of Pediatrics, Ehime University School of Medicine, Ehime, Japan 3 Department of Thoracic and Cardiovascular Surgery, Wakayama Medical University, Wakayama, Japan 4 Department of Pediatrics, Wakayama Medical University, Wakayama, Japan 5 Department of Cardiovascular Surgery, Kanto Medical Center, NTT East, Tokyo, Japan
Anomalous subaortic left brachiocephalic vein (ASLBV) is a rare systemic venous anomaly. We review our experience with patients associated with ASLBV who underwent cardiac surgery at three institutions. From 1989 to 2009, the medical records of surgically treated patients with ASLBV were analyzed; the incidence of ASLBV, clinical characteristics, and associated anatomical findings were assessed. Fifteen patients had ASLBV. All ASLBVs coursed left lateral to the aortic arch, passed under the ascending aorta anterior to the central pulmonary artery, and joined the right brachiocephalic vein. Fourteen patients had congenital heart disease (CHD), and the remaining patient did not have cardiac anomalies. Its incidence was 0.57% (14 of 2,449) in patients with CHD and only 0.02% (1 of 4,805) in patients without CHD. In patients with CHD, 73.3% (11 of 15) of the patients had conotruncal cardiac anomalies such as tetralogy of Fallot, ventricular septal defect with pulmonary atresia, truncus arteriosus, and interruption of the aortic arch. Eight patients had aortic arch anomalies, including right aortic arch and cervical aortic arch. The deletion of chromosomal 22q11.2 was confirmed in two patients, and one patient was diagnosed with DiGeorge syndrome. ASLBV was clinically silent even without any surgical intervention. ASLBV is a very rare anomaly and is highly associated with conotruncal cardiac anomalies and aortic arch anomalies, including right aortic arch and cervical aortic arch. Preoperative diagnosis is important when any surgical interventions are intended, especially, in patients with conotruncal cardiac anomalies. Clin. Anat. 23:950–955, 2010. V 2010 Wiley-Liss, Inc. C
Key words: anomalous subaortic left brachiocephalic vein; conotruncal cardiac anomalies; aortic arch anomalies
INTRODUCTION Anomalous subaortic left brachiocephalic vein (ASLBV) is a rare systemic venous anomaly (Kitamura et al., 1981; Shaffer et al., 1985; Smallhorn et al., 1985; Subirana et al., 1986). However, noninvasive imaging examinations, including echocardiography (Choi et al., 1990; Curtil et al., 1999; C 2010 V
Wiley-Liss, Inc.
*Correspondence to: Mitsugi Nagashima, MD, Department of Surgery, Stroke and Cardiovascular Center, Ehime University Hospital, Shitsukawa, Toon City, Ehime 791-0295, Japan. E-mail:
[email protected] Received 30 April 2010; Revised 29 June 2010; Accepted 29 July 2010 Published online 9 September 2010 in Wiley Online Library (wileyonlinelibrary.com). DOI 10.1002/ca.21046
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Fig. 1. Anterior (A) and left lateral (B) views of a multidetector-row computed tomography scan in a patient with tetralogy of Fallot with right aortic arch. Abnormal subaortic left brachiocephalic vein (ASLBV)
courses underneath the ascending aorta (As Ao) and anterosuperior to the central pulmonary artery (PA). It forms the superior vena cava (SVC) around the azygos vein insertion.
Morhy Borges Leal et al., 2002; Towbin et al., 1987) and three-dimensional computed tomography (Chen et al., 2005; Chern et al., 1999; Gu ¨lsu ¨n et al., 2003; Kim et al., 1994; Takada et al., 1992), have recently increased the recognition of this anomaly. Usually, the normal left brachiocephalic vein obliquely descends left to right, courses superior and anterior to the aortic arch, and joins the right brachiocephalic vein forming the superior vena cava (SVC). ASLBV usually runs left lateral to the aortic arch, passes under the ascending aorta, and joins the right brachiocephalic vein forming the very short SVC. In this report, we describe the clinical and anatomical characteristics of this anomaly and associated cardiac or aortic arch anomalies in 15 patients who underwent cardiac surgery at three institutions.
RESULTS
PATIENTS AND METHODS We reviewed surgical records between 1989 and 2009 at three institutions (Ehime University Hospital, Wakayama Medical University Hospital, and Kanto Medical Center NTT East Hospital); the medical records of patients with ASLBV were analyzed for the clinical characteristics and associated anatomical findings. The diagnosis of ASLBV was mainly confirmed by echocardiography, three-dimensional computed tomography, or cineangiography or by surgeons during operation.
Fifteen patients were diagnosed with ASLBV. These patients included seven men and eight women. All ASLBVs coursed left lateral to the aortic arch, passed under the ascending aorta anterior to the trachea and the central pulmonary artery, and joined the right brachiocephalic vein around the azygos vein insertion. Of the patients with ASLBV, 14 patients had congenital heart disease (CHD) among the 2,449 surgically treated patients at the three institutions. There was only one patient without CHD among the 4,805 patients who underwent cardiac surgery. This patient underwent total arch replacement for distal aortic arch aneurysm. The incidence in patients with CHD was 0.57% and that in patients without CHD was 0.02%. All 15 patients had situs solitus. In seven patients, this anomaly was diagnosed by operation. In the remaining patients, preoperative diagnosis was confirmed by echocardiography, three-dimensional computed tomography (Figs. 1 and 2), or cineangiography. Table 1 summarizes the clinical and anatomical characteristics of the patients. Eleven patients (11 of 15) had conotruncal cardiac anomalies such as tetralogy of Fallot, ventricular septal defect (VSD) with pulmonary atresia, truncus arteriosus, and interruption of the aortic arch with VSD. The deletion of chromosome 22q11.2 was confirmed in two patients, and one patient was diagnosed with DiGeorge syndrome. Among 15 patients, seven patients had right aortic arch (RAA) and one patient had cervical aortic arch in which the
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Fig. 2. Anterior (A) and posterior (B) views of a multidetector-row computed tomography scan in a low-birthweight neonate (body weight, 1.8 kg) with interruption of the aortic arch (Celoria and Patton anatomical classification type B, arch interruption between the left common
carotid artery and the left subclavian artery). Abnormal subaortic left brachiocephalic vein (ASLBV) courses underneath the small ascending aorta (As Ao) and forms the superior vena cava (SVC). The descending aorta (Des Ao) arises from the large patent ductus arteriosus.
apex of the aortic arch is cervically displaced above the clavicle. In one adult case associated with VSD with pulmonary atresia, a vein with the same course of the ASLBV was detected after the normal left brachiocephalic vein was occluded by a throm-
bus. In all patients, these ASLBVs were kept unchanged at the operation. There were no complications including thrombosis in this ASLBV or no clinical manifestations because of the oppression of the ASLBV.
TABLE 1. Clinical and Anatomical Characteristics Associated With ASLBCV in 15 Patients
Case
Other aortic arch or venous anomalies
Cardiac anomalies
Diagnosis of ASLBCV
Arch side
Echo Op Op Echo Echo Op Op CT Op
RAA RAA LAA RAA RAA RAA RAA LAA RAA
Aberrant LSCA
22q11.2 deletion
Op
LAA
PLSVC
DiGeorge syndrome
Echo Echo Echo Angiography CT
LAA LAA LAA RAA LAA
Aberrant RSCA KD, cervical arch, distal arch aneurysm
Gender
Age
1 2 3 4 5 6 7 8 9
F M M F F M F F F
2 1 1 1 2 2 1 28 1 month
10
M
6
TOF TOF TOF, AORPA TOF TOF TOF VSD, PA VSD, PA Truncus arteriosus DORV, PA, MS
11 12 13 14 15
F M M F M
1 month 5 4 months 6 70
IAA (B) ASD, PAPVC VSD VSD Normal heart
Chromosomal abnormality
22q11.2 deletion
Shaded columns represent cases with conotruncal anomalies. ASLBCV, abnormal subaortic left brachiocephalic vein; TOF, tetralogy of Fallot; Echo, echocardiography; RAA, right aortic arch; Op, operation; AORPA, anomalous origin of the right pulmonary artery from the ascending aorta; LAA, left aortic arch; LSCA, left subclavian artery; VSD, ventricular septal defect; PA, pulmonary atresia; CT, computed tomography; DORV, double outlet right ventricle; MS, mitral stenosis; PLSVC, persistent left superior vena cava; IAA, interruption of the aortic arch; PAPVC, partial anomalous pulmonary venous connection; RSCA, right subclavian artery; KD, Kommerell’s diverticulum.
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TABLE 2. Characteristics of Previously Reported Cases With Anomalous Subaortic Left Brachiocephalic Vein Abnormality of aortic arch
Congenital heart disease TOF VSD/PA DORV Truncus arteriosus VSD/IAA Tricuspid atresia VSD VSD/CoA AP window HLHS Right isomerism Left isomerism ASD Normal heart
No. of cases
Right
Left
Double
IAA
Unclear
135 (2) 88 16 5 2 3 3 6 1 1 1 5 1 3 59 (23)
89 (2) 71 (2) 8 1 2
39 16 8 4
1 1
3
3
3 2 2
1 1
3 1
1 1 1 1 9 (5)
1 4 2 40 (14)
5 (4)
5
The numbers of cervical aortic arches are shown in parentheses. IAA, interruption of the aortic arch; TOF, tetralogy of Fallot; VSD/PA, ventricular septal defect with pulmonary atresia; DORV, double outlet right ventricle; VSD/IAA, ventricular septal defect with interruption of the aortic arch; VSD/CoA, ventricular septal defect with co-arctation of the aortic arch; AP window, aortopulmonary window; HLHS, hypoplastic left heart syndrome; ASD, atrial septal defect.
DISCUSSION The incidence of ASLBV in patients with CHD was reported as 0.2% in necropsy studies (Gerlis and Ho, 1989), 0.5–0.98% in echocardiogram series (Choi et al., 1990; Curtil et al., 1999), and 1.7% by the computed tomography method (Chen et al., 2005). The prevalence from our report is consistent with that from the previous reports. The incidence in the patients without cardiac anomalies has not been precisely reported, but the incidence in our cardiac surgical patients without CHD was approximately 0.02%. Thus far, around 200 cases of this anomalous vein, including our cases, have been reported since 1980. All except seven patients had normally arranged atria (situs solitus). One patient had situs inversus associated with atrioventricular discordance, common atrioventricular valve, and pulmonary atresia in which the right brachiocephalic vein coursed beneath the left aortic arch and joined the left brachiocephalic vein (Choi et al., 1990). Of the remaining six patients, five patients had right isomerism heart (asplenia syndrome) (Chen et al., 2005; Morhy Borges Leal et al., 2002) and the other had left isomerism heart (Towbin et al., 1987). One hundred and forty-three patients had CHD and 59 patients did not have cardiac anomalies. Of the CHD patients, 135 patients were reported to be diagnosed with cardiac anomalies in detail (Chu et al., 2007; Kawara et al., 2003; Konstantinov et al., 2003; Koutlas et al., 1998). The male to female ratio was almost 1:1. Eighty-eight patients had tetralogy of Fallot or its analogous anomalies (Elami et al., 1995; Ito et al., 2001; Mill et al., 1993; Yilmaz et al., 2003), and 16 patients had VSD with pulmonary atresia (Choi et al., 1990; Ming et al., 2009; Morhy Borges Leal et al., 2002). Over 80% of the patients
had the so-called conotruncal cardiac anomaly. Of the patients with CHD, 66% had RAA. Only two cases with cervical aortic arch (Elami et al., 1995; Kim et al., 1999), which is presumed to result from (1) persistence of the third aortic arch and regression of the normal fourth arch, (2) lack of caudal migration of a normal fourth arch, or (3) fusion between the third and fourth arches combined with failure to descend into the thorax (Kumar et al., 1989), were reported. Other reported cardiac anomalies associated with this anomalous vein and their arch anomalies are shown in Table 2. The male to female ratio of the patients without CHD was approximately 1.7:1. RAA was observed in 17% of the patients without cardiac anomalies, and its incidence is much higher than that in normal subjects (Chern et al., 1999; Kim et al., 1999; Minami et al., 1993). Double aortic arch was also observed in 8% of the patients without CHD (Kim et al., 1999; Minami et al., 1993; Tsujimura et al., 2007). Cervical aortic arch was associated with ASLBV in approximately 40% of the patients without CHD (Bartoli et al., 1990; Khoury et al., 2008; Tu ¨rkvatan et al., 2009; Yama et al., 2005). Thus, in patients without CHD, the proportion of the cases associated with the cervical aortic arch and/or double aortic arch was quite higher than that in patients with CHD. In this way, ASLBV was also highly associated with abnormal aortic arch even in patients without CHD (Table 2). Most ASLBVs course left lateral to the aortic arch, traverse from left to right anterior to the trachea and anterior and superior to the central pulmonary artery, and cross posterior to the ascending aorta. They join the right brachiocephalic vein near the azygos vein insertion or very rarely join the azygos vein before entering the SVC (Ming et al., 2009). It has extremely rarely been reported that this anomalous
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Fig. 3. Diagrams showing the development of the normal and anomalous subaortic left brachiocephalic veins. A: Fourth to fifth week of gestation. B: Sixth to seventh week of gestation. C: Normal development in the seventh to eighth week of gestation. D: Normal development at birth. E: Anomalous subaortic left brachiocephalic vein at the seventh to eighth week of gestation. F: Anomalous subaortic left brachiocephalic vein at birth. 1, right anterior cardinal vein; 2, left anterior car-
dinal vein; 3, right posterior cardinal vein; 4, left posterior cardinal vein; 5, sinus venosus; 6, supracardinal vein; 7, coronary sinus; 8, third branchial arch; 9, fourth branchial arch; 10, primitive aorta; 11, disappearing dorsal aorta; 12, ventral precardinal anastomosis; 13, minor interconnections between the two precardinal veins, especially dorsal connection; 14, normal left brachiocephalic vein; and 15, anomalous subaortic left brachiocephalic vein.
vein connects with the left atrium and produces severe cyanosis (Townsend et al., 2008). The precise pathogenesis of ASLBV is still unknown. Embryologically, at the eighth week of normal fetal development, the ventral precardinal anastomosis develops between both the bilateral precardinal veins (Fig. 3). Then, the blood flows from left to right through this anastomosis. As a result, the proximal part of the left precardinal vein and left common cardinal vein disappears, whereas the ventral precardinal anastomosis becomes the left brachiocephalic vein (Fig. 3C). Rarely, this normal process does not advance and a left brachiocephalic vein anomalously courses in the subaortic area, traverses the mediastinum, and enters the SVC. Kim et al. (1999) speculated that some minor interconnections between the two precardinal veins may exist in the mediastinum other than the normal precardinal anastomosis. If the normal left brachiocephalic vein failed to develop, one of these interconnections may grow into the ASLBV. An abnormal aortic arch, including double aortic arch, cervical aortic arch, or RAA, which may develop between the fifth and seventh weeks of fetal development and precede the development of ventral precardinal anastomosis, may prevent the development of the ventral precardinal anastomosis. As a result, some minor interconnections between the two precardinal veins, especially dorsal connections, may develop (Fig. 3E and 3F). In fact, cases with double left bra-
chiocephalic veins (simultaneous normal and subaortic veins) (Takada et al., 1992), a case reported by Kim et al. (1994), and one case in our study in which a vein with the same course of ASLBV was detected after thrombotic obstruction of the normal brachiocephalic vein or SVC may support his hypothesis. Despite the theory, several cases were still reported with this anomaly but without any anatomical anomalies in the heart, aortic arch, and branching neck arteries (Amerasekera and McGuirk, 2010; Fujimoto et al., 1992; Nakamura et al., 2006). The ASLBV was described to be clinically asymptomatic if isolated, even with a compression between ascending aorta and trachea. The ASLBVs were mostly kept unchanged during the cardiac operation in the previously reported cases. In a case with tricuspid atresia and hypoplastic pulmonary artery, this vein was used as an augmentation material of the central pulmonary artery during cavopulmonary anastomosis (Agarwal et al., 2006). During the cardiac operation, great caution is required in the cases with ASLBV during dissection or manipulation of the central pulmonary artery or cross-clamping of the ascending aorta, especially during operations performed within a small surgical field. In conclusion, ASLBV is a rare anomaly and is usually associated with conotruncal cardiac anomalies. This anomaly is also highly comorbid with aortic arch anomalies such as RAA and cervical aortic arch. Although the ASLBV itself does not cause clinical
Anomalous Subaortic Left Brachiocephalic Vein symptoms, preoperative diagnosis is important when any surgical interventions are intended, especially, in patients with conotruncal cardiac anomalies. Further, the detection of this anomaly is possible by echocardiography or computed tomography.
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