Pulmonary Artery Dissection Caused by Extension of a Chronic Type A Aortic Dissection Through a Patent Ductus Arteriosus
A 41-year-old woman presented to our hospital with chest discomfort, cough, and worsening shortness of breath for 2 months. She had no history of connective tissue disease or family history of aortic catastrophes.
Five years before this presentation, she had undergone physical examination in a hospital, and transthoracic echocardiography showed type A aortic dissection. The patient, despite the advice of several cardiologists and cardiac surgeons, had always refused surgical correction.
Routine contrast-enhanced computed tomography and transthoracic echocardiography were performed. Imaging revealed a chronic type A aortic dissection originating from the aortic annulus and extending to the aortic arch that was associated with moderate aortic regurgitation. The aortic dissection infiltrated the pulmonary trunk through the patent ductus arteriosus (PDA; Figure 1). The concomitant anomaly was moderate mitral valve insufficiency diagnosed on the basis of transthoracic echocardiography. The patient underwent elective surgery. After induction of general anesthesia, the procedure was performed through a full median sternotomy under cardiopulmonary bypass with moderate hypothermic circulatory arrest at 25°C, right axillary artery cannulation for cardiopulmonary bypass, and selective antegrade cerebral perfusion.
On entry into the pericardium, the 3 arch vessels and PDA were exposed and surrounded. Cardiopulmonary bypass was instituted through axillary artery cannulation and the right atrium, with the left side of the heart venting from the right superior pulmonary vein. The PDA and ascending aorta were clamped. The ascending aorta was opened longitudinally, and both the left and right coronary arteries were found to originate separately from the left and right coronary sinuses. The pulmonary artery was opened longitudinally, and aortic dissection was found to be infiltrating the pulmonary trunk through the patent ductus arteriosus (Figure 2). After cold blood cardioplegia was given, a mitral valvuloplasty was performed through right atrium–atrial septal incision. The PDA was ligated. Pledgeted, double-armed, polypropylene sutures were placed across the detached inner and outer layers of the pulmonary artery and were tied over a second pledget. The false channel of pulmonary artery dissection was obliterated. The free intimal flaps and aortic leaflets were resected, and subsequently, a valved conduit was sewn to the aortic annulus with a 2-0 running Prolene suture. A big opening was made into the side of the graft for anastomosing the left and right coronary ostia, which was done by inclusion. When the patient was cooled to 25°C, the aortic clamp was removed, and the bypass was restricted to the axillary artery at 5 mL·kg−1·min−1. The arch vessels were clamped separately; selective cerebral perfusion was started; and then the aortic arch was opened longitudinally. The left carotid artery was transected at its origin from the arch. The aortic arch was transected between the left carotid artery and the left subclavian artery, which was transected 5 mm distal to its origin from the arch. The aneurysmal and dissected innominate artery was transected at its origins from the aortic arch. As the initial step of the procedure described by Sun et al,1 the special stent graft was inserted into the descending aorta and deployed, taking only an instant, often only a matter of seconds.
Subsequently, the proximal sewing curtain of the stent graft was retrieved and exposed, and a distal anastomosis was performed between the proximal end of the stent graft and a new 4-branch Dacron graft, which would be the new aortic arch, incorporating the wall of the aorta. At this point, distal perfusion was begun through the perfusion limb of the 4-branch graft, thus restoring lower-body flow. No bleeding or enlargement of the false lumen through the PDA in the pulmonary artery was seen. The pulmonary artery incision was sutured. Next, the left carotid artery was anastomosed to the second 8-mm arch branch from the graft in an end-to-end fashion. Then, rewarming was begun, and the left carotid artery was opened to flow after deairing. The innominate artery was then anastomosed to the 1-cm arch limb of the 4-branch graft; it was opened to flow shortly after deairing, and bilateral cerebral perfusion was restored at this point. Proximal anastomosis was constructed by suturing the 4-branch graft to the distal end of the valved conduit. The ascending aorta was now thoroughly deaired and unclamped, and the heart resumed beating. Finally, the left subclavian artery was anastomosed to the right 8-mm arch branch of the 4-branch graft.
The residual aortic tissues were approximated to cover the surgical site and to create a Cabrol fistula from the graft space to the right atrium. The extraperfusion limb of the 4-branch graft was cut and oversewn, followed by weaning of the patient from cardiopulmonary bypass. Protamine was administered, and the procedure was completed in a routine fashion.
The patient’s postoperative course was uneventful without any noteworthy symptoms. Routine contrast-enhanced computed tomography and transthoracic echocardiography were performed. Imaging revealed residual descending aortic and pulmonary artery dissection with thrombogenesis in the false lumen (Figure 3). The patient was discharged 20 days postoperatively.
This is a case of chronic type A aortic dissection infiltrating the pulmonary trunk through the PDA. It is potentially fatal, and there are no reported cases. Dissection of the pulmonary artery has previously been described in cases of pulmonary artery aneurysms associated with either severe pulmonary hypertension2 or congenital heart malformations and in cases of connective tissue disorders. In acute type A aortic dissection, aortopulmonary fistulization or thrombosis of the pulmonary artery has been reported.3 To the best of our knowledge, pulmonary artery dissection has never been described in association with aortic dissection. In this case, the patient presented with type A aortic dissection 5 years after the initial diagnosis. We speculated that the infiltration could dissect the layers of the pulmonary artery wall through the PDA.
Sources of Funding
This work was supported by grants from the National Natural Science Foundation of China (81300174 and 31330029).
- © 2015 American Heart Association, Inc.
- Sun LZ ,
- Ma WG ,
- Zhu JM ,
- Zheng J ,
- Liu YM ,
- Ziganshin BA ,
- Elefteriades JA.
- Russo V ,
- Zompatori M ,
- Galiè N.
- Ibe R ,
- Bahktiari N ,
- Davidson C ,
- Hildick-Smith D ,
- Lewis M.