Complicated acute type B aortic dissection with involvement of an aberrant right subclavian artery and rupture of a thoracoabdominal aortic aneurysm, Crawford type I: Successful emergency endovascular treatment

Abstract

Although an aberrant right subclavian artery (ARSA) is the most common abnormality of aortic arch development, it is an unusual entity to encounter associated with thoracic aortic dissection. We report the successful endovascular treatment of this association in a critically ill patient. An 80-year-old man was referred to our institution with the diagnosis of an acute aortic Stanford type B dissection (Figure 1, A). The computed tomographic scan images also showed a thoracoabdominal aortic aneurysm extending from an ARSA (Figure 1, B) to the esophageal hiatus (Crawford type I). Because of persistent back pain despite correct intravenous treatment, a new computed tomographic scan was repeated 8 hours later, revealing progression of the aortic dissection and the appearance of a left-sided hemothorax. Blood analysis also showed a fall of 10 points in the hematocrit value. Because of the patient’s critical status and high surgical risk, emergency endovascular treatment was indicated. Notwithstanding, the procedure was technically demanding, because the endograft had to be deployed while avoiding occlusion of the ARSA. However, the diameter of the aortic aneurysm distal to the origin of the ARSA was greater than 46 mm, which is the maximum diameter amenable for the standard Medtronic Valiant thoracic endograft (Medtronic, Inc, Santa Rosa, Calif). Therefore, the deployment of the endoprosthesis was adjusted to the origin of the ARSA, where the thoracic aneurysm had a neck of 42 mm. A Valiant endograft, 160 mm in length and 46 mm in diameter, was deployed at the level of ARSA origin, so that its floppy FreeFlo straight portion (Figure 2, A), which is fenestrated, allowed blood flow through the artery. In this way, the flow through the aberrant artery was preserved (control computed tomographic scans, Figure 2, A and B). There were no significant variations of invasive radial pressure (<10 mm Hg) between the two arms. The patient was discharged from the hospital 6 days later. Aberrant subclavian artery, also called arteria lusoria, was first described by Bayford in 1794. It is the most common form of aortic arch anomaly and has a reported incidence of 0.5% to 2%. It results from regression of the right fourth aortic arch between the carotid and subclavian arteries.1Felson B. Cohen S. et al.Anomalous right subclavian artery.Radiology. 1950; 54: 340-349PubMed Google Scholar The association of aortic dissection and ARSA is rarely encountered; however, it has very important implications in treatment, either surgical or endovascular. A number of surgical techniques have been proposed for treatment of this pathologic condition. These include transposition or bypass of the distal portion of the aberrant artery into the adjacent carotid artery, resection of the origin of the aneurysm from the descending thoracic aorta, and repair of the aortic dissection/aneurysm with the elephant trunk technique.2Borst H.G. Walterbusch G. Schaps D. Extensive aortic replacement using “elephant trunk” prosthesis.Thorac Cardiovasc Surg. 1983; 31: 37-40Crossref PubMed Scopus (483) Google Scholar The use of partial or total cardiopulmonary bypass, hypothermia, and circulatory arrest is normally necessary. Nevertheless, endovascular therapy has revolutionized this surgery. Complex open surgical procedures may be replaced by endovascular treatment, which is associated with a lower perioperative morbidity and mortality.3Kouchoukos N.T. Masetti P. Aberrant subclavian artery and Kommerell aneurysm: surgical treatment with a standard approach.J Thorac Cardiovasc Surg. 2007; 133: 888-892Abstract Full Text Full Text PDF PubMed Scopus (93) Google Scholar In this case, the very high surgical risk of the patient led us to choose an endovascular treatment. We decided to use the Valiant system, which is a third-generation endoprosthesis designed specifically for the exclusion of thoracic aortic disease.4Brooks M. Loftus I. Morgan R. Thompson M. The Valiant thoracic endograft.J Cardiovasc Surg (Torino). 2006; 47: 269-278PubMed Google Scholar Its floppy FreeFlo straight portion allowed us to deploy the endograft without occluding the ARSA and, therefore, without compromising either the right arm blood supply or the right vertebral artery flow. Dr Mosquera