Ann Thorac Surg 2003;76:1301-1303
© 2003 The Society of Thoracic Surgeons
Case report
Aortic dissection coexistent with two saccular aneurysms
Hitoshi Hirose, MD, FICSa,
Lars G. Svensson, MD, PhDa*
a Center for Aortic Surgery and Marfan and Connective Tissue Disorder Clinic, Department of Thoracic and Cardiovascular Surgery, Cleveland Clinic Foundation, Cleveland, Ohio USA
Accepted for publication March 17, 2003.
* Address reprint requests to Dr Svensson, Center for Aortic Surgery and Marfan and Connective Tissue Disorder Clinic, Department of Thoracic and Cardiovascular Surgery, F25, Cleveland Clinic Foundation, 9500 Euclid Ave, Cleveland, OH 44196, USA
e-mail: svenssl{at}ccf.org
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Abstract
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We report a rare case of DeBakey type I aortic dissection coexistent with two saccular aneurysms adjacent but not communicating with the aortic dissection.
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Introduction
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Saccular aneurysms may be the site of origin of aortic dissection [1–3]. Separate saccular aneurysms with no communication with the aortic dissection process appear to be rare.
A 64-year-old man with a history of hypertension and of chest pain about 10 years ago came to the emergency room complaining of chest pain. He had no history of chest trauma or fever of unknown origin. Computed tomography scan with contrast revealed acute DeBakey type I dissection from the ascending aorta into the arch with a maximum diameter of 5.5 cm (Fig 1).
The descending aorta appeared normal; however there were two saccular aneurysms, one of which was located just proximal to the left subclavian artery and another just distal to it (Fig 2).
Transesophageal echocardiography demonstrated severe (4+) aortic insufficiency with a small pericardial effusion.
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Fig 1. Enhanced computed tomography scan of the chest shows the aortic dissection in the ascending aorta. The dissection flaps were thin and reproduced poorly but are seen near the left main ostium (arrow).
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Fig 2. Enhanced computed tomography scan of the chest shows the presence of saccular aneurysms: one on the greater curvature of the aorta just distal to the left subclavian artery (long arrow) and another in the lesser curvature just proximal to the left subclavian artery (short arrow). Note the dissection flap septum in the middle of the distal ascending aorta and how the dissection flap terminates at the base of the proximal saccular aneurysm.
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The patient was immediately taken to the operating room. The right subclavian artery was dissected out first through a right infraclavicular incision. Upon mediansternotomy a hemopericardium and a hematoma in the ascending aorta were noted. After heparin administration an 8-mm side graft was sewn onto the right subclavian artery, cardiopulmonary bypass was established using the right subclavian artery for inflow and the right atrium for drainage, and the patient was cooled. The ascending aorta was cross-clamped and retrograde cardioplegia given to obtain cardiac arrest because of aortic regurgitation. After clamping the aorta, the ascending aorta was opened and a proximal intimal tear was noted just above the sinotubular junction although the leaflets of the aortic valve and orifices of the coronary arteries were intact. The aortic root was excised down to the annulus, the aortic valve preserved, and the aortic root remodeled by scalloping the proximal graft. Because of the enlarged annulus a subannular aortic annuloplasty was performed before root remodeling using a polytetrafluoroethylene suture tied around a 19-mm Hegar dilator in the left ventricular outflow tract to resize the annulus to the normal size.
Under deep hypothermic circulatory arrest (20°C) the aortic clamp was released and then the aorta was opened longitudinally from the origin of the innominate artery down into the descending aorta. The dissection involved the arch but did not extend beyond the left subclavian artery. Two separate chronic saccular aneurysms distal to the dissection were observed. The dissection process stopped at the proximal edge of the saccular aneurysm and terminated in dense scar tissue but did not communicate with them. One was located in the greater curvature of the aorta just distal to the left subclavian artery with the size of 3 x 3 x 3 cm, and another was in the lesser curvature just proximal to the left subclavian artery with a size of 4 x 4 x 4 cm. There was an old clot in the saccular aneurysm and both had thick fibrous walls. The saccular aneurysm in the descending aorta was closed with interrupted pledgeted 2-0 Prolene (Ethicon, Somerville, NJ) sutures. A 26-mm polyester graft was thereafter parachuted using long 3-0 Prolene sutures into the middescending aorta excluding the saccular aneurysm repair and preserving the left subclavian artery. This was done to ensure no leakage into the old saccular aneurysm sac and for sewing the subclavian artery to the graft. During the distal anastomosis antegrade brain perfusion was performed by occluding the innominate artery with an occlusion balloon placed in the innominate artery and perfusing the right subclavian artery at a flow rate of 200 mL/min through the previously attached 8-mm side graft. Then the neck vessels including the left common carotid and innominate arteries were reconstructed separately as a Carrell patch island and anastomosed onto the graft. This was done because of the separation between the left subclavian artery and the left common carotid artery. After the reconstruction of the neck vessels the proximal end of the graft was clamped, cardiopulmonary bypass was restarted, and the patient was rewarmed. The proximal anastomosis was then performed. Weaning from cardiopulmonary bypass and postoperative recovery was uneventful and the patient was discharged home on postoperative day 8 without aortic regurgitation. Histologic examination revealed mild cystic medial necrosis and cultures failed to grow any organisms.
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Comment
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In a study by Roberts and Roberts [1] a separate true aortic aneurysm was found in 7% of patients (13 of 182) who died of aortic dissection. In the Japanese literature there is a case report of a distal arch saccular aneurysm associated with aortic dissection and considered to be the source of the dissection [2], and has also been noted previously by us [3]. Although aortic dissection originating from a saccular aneurysm is not infrequent [3] in our patient the saccular aneurysms were not the source of the dissection. Our case with two isolated saccular aneurysms found in a patient with acute DeBakey type I dissection appears to be very rare. Arteriosclerosis plaques in aneurysms play a role in preventing the extension and propagation of dissection beyond the atherosclerotic aneurysm. In our case although the saccular aneurysms were not involved by the dissection, the dissection process stopped before them. Roberts and Roberts [1] reported that no dissection extended beyond aneurysms in their series of aneurysms coexisting with aortic dissection. However rupture was observed immediately proximal to the aneurysms in patients who died because of the dissection. The outer wall of the false lumen of the dissection was noted to be thinner because of the presence of the true aneurysm. The saccular aneurysms located adjacent to the dissection in our patients resulted in a high risk for free rupture and indeed there was an extravasation of blood in the area.
The reason for the saccular aneurysms is unclear. With our patient’s history of previous chest pain it is possible that he had a localized dissection of the arch that healed, resulting in two saccular aneurysms. The other possible etiology of the saccular aneurysm was a past mycotic aneurysm; however he had no history of a fever of unknown origin. We believe the dissection in this patient was not related to the old saccular aneurysm; however the saccular aneurysm does indicate that he had an abnormally weak aorta although the scar tissue around the two saccular aneurysms prevented extension of dissection further down to the descending aorta. The finding of an enlarged root and cystic medial necrosis does account for the proximal aortic dissection but not necessarily for the arch saccular aneurysms. It would be very unusual for saccular aneurysms to have formed in the arch from cystic medial necrosis yet have spared the root form dissection when the saccular aneurysm originally developed.
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References
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- Roberts C.S., Roberts W.C. Combined thoracic aortic dissection and abdominal aortic fusiform aneurysm. Ann Thorac Surg 1991;52:537-540.[Abstract/Free Full Text]
- Koushima R., Kikuchi Y., Sakurada T., Kusajima K. A case of Stanford type A acute aortic dissection associated with a distal arch atherosclerotic aneurysm. J Jpn Assoc Thorac Surg 1998;46:1190-1193.
- Svensson L.G., Crawford E.S. Cardiovascular and vascular disease of the aorta. Philadelphia: WB Saunders, 1997.
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[Abstract]
[Full Text]
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Abstract
Introduction
