Background

A true saccular aneurysm in the ascending aorta is extremely rare. Focal or diffuse dilatation of an artery may be classified pathologically as: true aneurysm, in which all three layers of the vessel wall are intact; false aneurysm, in which none of the three layers are intact; or pseudoaneurysm, in which one or two layers remains intact [₁, ₂]. Usually, true aneurysms are fusiform and false aneurysms are saccular [₁], but there can be exceptions to this general rule. Majority of ascending aneurysms are involved in the Valsalva sinuses [₃], rest of the cases we have met in literature are due to surgical trauma [₄] or aortitis [₅].

Case

We present a rare case of an ascending aorta saccular aneurysm in a 56-year-old male patient who underwent elective coronary artery bypass surgery. The patient was completely asymptomatic except his ischemic coronary symptomes. He had smoking and hypertension as risk factors. There was no reported prior trauma. Laboratory data of either syphilitic or other microbial infections were negative. Pre-operative chest x-ray and echocardiography were normal.The aortagraphy did not documented the presence of the aneurysm.

When pericardiotomy was made, a 30x30x20 mm sized tumor on the proximal ascending aorta was detected. The aneurysm which showed a spherical bulging on ascending aorta was incidentally met during the coronary bypass operation (Fig 1a). The diagnosis was confirmed by surgery itself (Fig 1b).

Resection was preferred because of the usual suspicion of spontaneous rupture and the morphology and size of the aneurysm. After distal coronary anostomoses, the saccular aneurysm with a large neck and an extremely thin wall was resected and thrombus material was evacuated from inside. The ascending aorta was repaired with an 30x30mm woven dacron patch graft and the proximal anostomoses were implanted to the aorta by the usual method. Furthermore, microscopy of the aneurysm wall demonstrated fibromuscular dysplasia and severe medial layer atrophy. The postoperative course was uneventful.

Figure 1

Figure 1: A) A 30x30x20 mm sized tumor on the proximal ascending aorta was detected. B) Saccular aortic segment was resected with its thrombus material inside. C) Patchplasty is shown on the ascending aorta.

Comment

True saccular aneurysms are very rare and reported mainly at the aortic isthmus and descending aorta [₆]. Aortagraphy and computerized tomography are the mainly used tools for diagnosis. Aneurysms are diagnosed generally during routine control or by clinicians' suspicion in high-risk patients. We diagnosed the thrombosed aneurysm during the operation incidentally.

Traumatic aneurysms are characteristically either false aneurysms or pseudoaneurysms. Most cases of traumatic rupture of the aorta are lethal [₁, ₇]. Congenital aneurysms, arteritis-related aneurysms (as in Takayasu's arteritis or giant cell arteritis) and aneurysms associated with Marfan syndrome or Ehlers Danlos syndrome are less common. Among the causes of aortic aneurysms are atherosclerosis, syphilis, trauma, bacterial infection, arteritis, connective tissue disorders and neoplasm. Most of them are fusiform, although up to 20 percent may be saccular. Usually they are seen in the thoracic and abdominal aorta. Large size, increased patient age and high diastolic blood pressure are also negative factors [₁, ₇].

In our case, we did not find an accused reason except atherosclerosis. Moreover, the aneurysm was situated on ascending aorta at the great curvature and its nature was a true saccular aneurysm, which was charged with thrombus. In the literature, we could not find another primary (atherosclerotic, multifactorial) true ascending aortic saccular aneurysm.

Since small saccular aneurysms are asymptomatic, they can not be identified. The diagnosis of thrombosed ones is even harder. These reasons limit the diagosis as in our case. Diagnosis can be made by visualization techniques like computed tomography, aortography, and echocardiography, or by direct visualization during open heart surgery.

Treatment in aneurysms is surgery or endovascular repair currently. Different surgical techniques are used in saccular aneurysms [₈], in such limited aneurysm we preffered resection of the aneurysmal sac and repair the aorta with dacron patch.

Sometimes luck keeps alive the patient. Careful management and radical decisions can carry on life and protects the surgeon from unexpected fatal complications. In light of the high risk of rupture, which was proved to be present by the very thin aneurysm wall at the time of surgery, we suggest early surgical treatment of this rare saccular ascending aortic aneurysms in open heart surgery patients regardless of aneurysm diameter.