Interrupted aortic arch with severe aortic stenosis in an adult bicuspid aortic valve patient

Abstract

Interrupted aortic arch (IAA) is a rare congenital anomaly with a high mortality rate if left unoperated in infancy. Very few cases have been reported in adults so far. In this article, we are describing a case of IAA in a 28-year-old male patient. It was associated with bicuspid aortic valve (BAV) leading to severe aortic stenosis (AS). To our knowledge, very few complex cases involving trio of IAA with BAV and AS have been reported so far.

Introduction

Interrupted aortic arch (IAA) is a rare congenital anomaly with prevalence of 0.06 per 1000 live births. Incidence is even rarer in adult population with only 30 cases reported so far [1]. Approximately 75% of babies with IAA die in their first month and only 10% make it past the first year of life without surgical intervention [2].

Some cardiac malformations like patent ductus arteriosus, ventricular septal defect, bicuspid aortic valve (BAV), left ventricular outflow tract obstruction, and aortopulmonary window have been found to be associated with IAA [3].

Here, we are presenting a rare case of type A IAA with severe aortic stenosis (AS) due to BAV in an adult patient who underwent surgical aortic valve replacement (AVR) with extra-anatomic bypass for IAA.

Case report

A 28-year-old male patient was admitted with complaints of shortness of breath on exertion since few months. On examination, he was found to have palpable upper limb pulsations but lower limb pulses were absent. He also had upper limb hypertension with blood pressure of 160/90 mmHg in the upper limbs, while lower limb blood pressure was 80/60 mmHg. His two-dimensional (2D) echocardiography revealed BAV with peak systolic gradient/mean systolic gradient of 100/62 mmHg causing severe AS. There was severe left ventricular hypertrophy and ejection fraction was 65%. Computed tomography (CT) aortogram was performed which was suggestive of type A IAA; aortic arch was interrupted 1.6 cm distal to the left subclavian artery and descending thoracic aorta (DTA) filling through bridging collaterals of bilateral subclavian arteries and dorsal collaterals (Fig. 1). Aortic dimensions were within normal limits (annulus, 2.2 cm; aorta at coronary sinus, 3.1 cm; at sino-tubular junction, 2.5 cm; mid-ascending aorta, 2.3 cm).

Fig. 1.

CT aortogram showing type A interrupted aortic arch

With all these preoperative findings, diagnosis of IAA was made even in the absence of patent ductus arteriosus (PDA). Intraoperatively, the ascending aorta was not dilated, the aortic valve was bicuspid with calcification present over leaflets and extending until the annulus, the annulus was small, and commissures were fused. The patient underwent AVR with mechanical valve (19 mm Sorin) and extra-anatomic bypass for IAA. Extra-anatomic bypass was done between the ascending aorta and distal DTA with 18-mm Dacron graft which was routed above the inferior vena cava (IVC) (Fig. 2a, b). All the peripheral pulses of both the lower limbs were palpable in the postoperative period. In addition, equalization of systemic pressures in upper limbs and lower limbs was achieved. Recovery was uneventful and the patient was discharged on the 6th postoperative day after confirming normal functioning of surgically constructed extra-anatomic bypass on CT aortogram (Fig. 3a, b).

Fig. 2.

a Dacron graft to DTA end-to-side anastomosis. b Ascending aorta to Dacron graft end-to-side anastomosis

Fig. 3.

a, b Postoperative CT aortogram showing extra-anatomic bypass for type A IAA

Discussion

IAA is defined as complete luminal and anatomical interruption between the ascending and descending aorta. First classified by Celoria and Patton [4], IAA has been divided into three types based on the location of the interruption: type A is discontinuity distal to the left subclavian artery, type B is discontinuity between the left common carotid and the left subclavian artery, and type C is discontinuity between the innominate and left common carotid artery. In neonates, type B is the most common variant representing about 53% of the cases, followed by type A (43%) and type C (4%).

Most common presentation of IAA in infants is congestive heart failure. If left untreated, 90% of the infants die in first year of life. In the absence of shunt lesions, survival to adulthood is possible only through collateral circulation [5] and the same was seen in our patient.

A literature review of 30 cases of IAA in patients more than 18 years of age has been reported in which 79% of the patients were found to have type A, followed by 16% with type B and 3% with type C. The average age of diagnosis in this review was 39.4 years (range, 18–72 years) and most patients (74%) were men [6]. Adult patients can present with wide variation of symptoms which include being asymptomatic to presence of headache, malaise, hypertension, claudication, differential blood pressure in arms and legs, and congestive heart failure. Palpation of peripheral pulses plays pivotal role in clinical suspicion of IAA [7]. Hypertension refractory to medical management has been seen in 70% of the patients. The blood pressure in the lower extremities is markedly diminished compared with that in the upper extremities, and the gradient across the interruption can vary from 50 to 130 mmHg [8].

Chest X ray may be normal or may show cardiomegaly and sometimes rib notching can be appreciated. 2D echocardiography has its limitation for evaluating distal arch of aorta and proximal DTA, but is useful in detecting associated cardiac anomalies like BAV [1]. CT aortogram is considered gold standard for diagnosis of IAA as it provides high-resolution three-dimensional imaging of IAA as well as precise site and extent of collateral circulation [1]. Therefore, CT aortogram and 2D echocardiography are mandatory investigations for detailed preoperative diagnosis in order to plan a definitive surgical approach.

IAA has been found to be associated with other cardiac anomalies. In our patient, it was associated with BAV. The most common complication associated with BAV is development of AS (60–80%).

Preferred management of adult IAA includes surgical correction of not only IAA, but also associated cardiac anomalies which aims to restore downstream blood flow and avoid upstream high blood pressure complications [1]. Surgical options are considered depending on the discontinuation site which include extra-anatomic bypass, end-to-end anastomosis of both ends of the IAA, graft interposition, and percutaneous stent placement [9]. Extra-anatomic bypass via midline sternotomy incision is the preferred technique in adult patients as there are concerns of hemorrhage from well-developed collateral vessels [8]. It also helps in correcting associated cardiac anomalies from a single incision.

BAV is often associated with aortopathy with incidence being 33%, but in our case, intraoperatively, the ascending aorta was found to be heathy and not dilated which correlated with preoperative CT aortogram findings. Hence, we performed extra-anatomic bypass between the ascending aorta and distal DTA using 18-mm Dacron graft and stenotic BAV was replaced with a mechanical bileaflet valve.

Surgical correction yields successful postoperative outcomes in most patients in terms of correction of upper body hypertension leading to discontinuation of antihypertensive medications along with equalization of upper and lower body systemic pressures and symptomatic improvement [5, 8].

We conducted a PubMed search for IAA cases in adults using the MeSH terms “IAA,” “adult patients,” and “BAV.”

Conclusion

We present a rare case comprising trio of IAA with BAV and AS in an adult patient and its successful surgical management. Infants without intracardiac shunt lesions can survive to adulthood with development of good collateral circulation. For diagnosing IAA in adulthood, clinical suspicion is required as most patients can be asymptomatic. A thorough clinical examination followed by radiological investigations provides a definitive diagnosis which should be then followed by proper planning and execution of complete surgical correction.

Funding

None.

Declarations

Ethics approval

Not applicable.

Informed consent

Appropriate and detailed patient consent has been taken.

Human and animal rights statement

All procedures performed in this study involving human participants were in accordance with the ethical standards of the institutional research committee and with the 1964 Helsinki Declaration and its later amendments or comparable ethical standards. This article does not contain any studies with animals performed by any of the authors.

Conflict of interest

There are no conflicts of interest.