336 Ann Thorac Cardiovasc Surg Vol. 14, No. 5 (2008)

CaseReport

Asymptomatic Spontaneous Ruptureof a Nonaneurismal Visceral Aorta

Masaki Yada, MD, PhD, Yasumi Maze, MD, PhD, Toshiya Tokui, MD, PhD, and

Sekira Shomura, MD, PhD

From Department of Thoracic and Cardiovascular Surgery, Yamada Red Cross Hospital, Ise, Japan

Received June 8, 2007; accepted for publication July 30, 2007Address reprint requests to Masaki Yada, MD, PhD: Department of Thoracic and Cardiovascular Surgery, Yamada Red Cross Hospital, 810 Misono, Ise 516–0805, Mie, Japan.

Spontaneous nonaneurysmal rupture of the aorta is a life-threatening condition for which emergency diagnostic and therapeutic measures are indicated. An asymptomatic spontaneous aortic rupture was unexpectedly discovered adjacent to the visceral aorta. We diagnosed the mass as a pseudoaneurysm, and surgery was performed. This was the first reported case of asymptomatic spontaneous rupture of a nonaneurysmal visceral aorta. (Ann Thorac Car-diovasc Surg 2008; 14: 336–338)

Key words: asymptomatic spontaneous rupture, nonaneurismal visceral aorta, penetrating ath-erosclerotic ulcer　

The patient came to our department on foot. General fatigue had already disappeared. He had been enjoying good health until then, had no history of hypertension, and had taken no medication. There was no pain, no history of trauma, and no fever. He was admitted to our hospital for the observance of a mass. At that point, we couldn’t figure out the relation to the mass and general fatigue or weight loss of which the patient had com-plained several months earlier. On admission, his blood pressure, body temperature, and white blood cell count were 110/70 mm Hg, 36.5C°, and 2.9 × 109/L, respec-tively. He had no symptoms at the abdomen, neither palpable nor pulsatile mass. Mild anemia existed, with a hematocrit value of 25.4%. Recently, he had pointed out mild renal failure; the creatinine level was 3.6 mg/dl. After a few days, a repeat CT scan suggested an increasing size of the mass; therefore we strongly sus-pected that the mass was a pseudoaneurysm. There was no sign of aortic dissection or aneurysm. The pseudoan-eurysm existed just above the level of the celiac axis.

With the high risk of pseudoaneurysm rupture, surgi-cal treatment was the only hope to save this patient. The surgical treatment was performed. There were no aneu-rysmal changes or dissection at the aorta. The normal size of the aorta was isolated at the proximal and distal sites of the pseudoaneurysm, which was recognized just above the celiac axis (Fig. 2). There was no pus in the pseudoaneurysmal sac, and no infectious change was recognized. After opening the visceral aorta longitudi-

Introduction

Spontaneous rupture of the abdominal aorta is a rare event. In all cases, patients suffer from severe pain, including chest, abdominal, and back pain. In this case, the patient had no symptoms from the spontaneous rup-ture of a nonaneurysmal visceral aorta.

Case Report

A 74-year-old man was referred from medicine to our department concerning a mass adjacent to the visceral aorta. The patient had general fatigue and several months earlier a weight loss. He took an ultrasonography that showed a mass near the abdominal aorta and pancreas. At first a physician suspected the mass to be a pancreas carcinoma. A computed tomography (CT) scan was done immediately, indicating that there was no tumor in the pancreas. However, a mass was recognized on the visceral aorta. Magnetic resonance imaging (MRI) (Fig. 1) was done at the same time, and the shape of the mass was found to be an infectious aortic aneurysm.

Asymptomatic Rupture of Visceral Aorta

Ann Thorac Cardiovasc Surg Vol. 14, No. 5 (2008) 337

nally, we found a lack of aortic wall at the right anterior aspect of the visceral aorta. The large pseudoaneurysm was confined to the retroperitoneal space without thrombus. Mild atherosclerotic change was found around the area of perforation. However, there was no evidence of aortic dissection or aortic aneurysm. The aortic wall was resected and replaced with an 18 mm woven Dacron graft. On day 4 after the operation, the patient suffered acute respiratory failure, which resulted in disseminated intravascular coagulation (DIC) and multiple organ failure (MOF). The patient died on day 16.

A pathological examination of the resected specimen revealed an atherosclerotic change with calcification and fibrous thickening of the intima. However, there was no evidence of dissection, cystic medial necrosis, or hematoma in the media. Also, we found no signs of inflammation or bacterial invasion.

Discussion

Not associated with aortic aneurysm, dissection, trauma, medically induced, inflammation or infection of the aortic wall, erosion from a neoplastic mass or secondary to surgery, spontaneous aortic ruptures are very rare events, but fatal. To our knowledge, 17 cases of spontaneous abdominal aortic rupture have been reported in the English literature. Moreover, this is the third reported case of a spontaneous contained rupture of the visceral aorta.1,2) All of the patients came to the hospital because of pain, including chest, flank, back, and abdominal pain. Some cases were sudden onsets,

and some were chronic.3) Moreover, complaints varied widely and included nausea and vomiting; the most serious situation was shock. Does and Brouwer4) reported painless spontaneous rupture in their litera-ture, but the patient had mild abdominal discomfort and pulsatile abdominal swelling. In our case, the patient did not complain when he was admitted. A preoperative CT scan and an MRI showed a suspected infectious aortic aneurysm, but there were no signs of infection in the preoperative physical examination. To make a pre-operative diagnosis in the usual cases of spontaneous aortic rupture is complicated.5) The asymptomatic spontaneous rupture that we experienced was more dif-ficult to diagnose preoperatively. Ashcraft et al.6) concluded in his report that a diagnosis of spontaneous aortic rupture was often delayed. Lastly, we decided to operate because the size of the mass surrounding the aorta was increasing, as seen in the secondary CT scan. We diagnosed the mass as a pseudoaneurysm, and then we considered the risk of a rupture.

Fig. 2. A pseudoaneurysm was recognized just above the celiac axis.

The normal size of the visceral aorta was found.

Fig. 1. A sagittal section of magnetic resonance imaging (MRI) shows the mass continuing from the visceral aorta (arrows).

Pseudo-aneurysm

Cel iac a .

338

Yada et al.

Ann Thorac Cardiovasc Surg Vol. 14, No. 5 (2008)

The precise mechanism of spontaneous rupture is not well known. The leading pathological findings from the spontaneous aortic rupture were atherosclerotic change with longstanding hypertension.7) Some reports indicated that a calcification of the aorta might play an important role in perforation. Our case had atherosclerotic change and calcification of the aorta in the pathological exami-nation, but no history of hypertension.

Recently, Stanson et al.8) reported as a new clinical entity that penetrating atherosclerotic ulcers (PAUs) could be regarded as a cause of aortic rupture. A PAU of the aorta is an ulceration of an atherosclerotic plaque that penetrates the intima. It results in aortic intramural hematoma, adventitial pseudoaneurysm formation, or aortic rupture. Nora and Hollier suggest that a PAU may be an initial form of perforation.1) Braverman9) reported that PAU might lead to aortic complications, including aortic rupture or pseudoaneurysm formation. Almost all reports about PAUs indicate that they are usually accompanied by pain, but the mechanism of pain is obscure. In our asymptomatic case, the result of the pathological examination showed that a thickening of the intima and atherosclerotic change were found. So we considered that in this case the perforation might have been caused by a PAU.

In summary, a case of a 74-year-old man with spon-taneous rupture of a nonaneurism visceral aorta is described. The asymptomatic case was very rare and difficult to diagnose. We conclude that PAU might be an important cause of a spontaneous aortic rupture.

Acknowledgments

We thank Ms. B. Tishkoff for critically reading the man-uscript.

References

1. Nora JD, Hollier LH. Contained rupture of the supra-renal aorta. J Vasc Surg 1987; 5: 651–4.

2. Curi MA, Skelly CL, Woo DH, Desai TR, Winterfield R, et al. Spontaneous perforation of a non-aneurismal visceral aorta. Cardiovasc Surg 2002; 10: 279–83.

3. Copping GA. Spontaneous rupture of abdominal aorta. J Am Med Assoc 1953; 151: 374–6.

4. Does RT, Brouwer KJ. Spontaneous rupture of the abdominal aorta without pre-existing aneurysm—two case reports. Eur J Vasc Endovasc Surg 1997; 14: 408–9.

5. Handa N, Takamoto S, Hatanaka M, Minoshima T, Morota T, et al. Spontaneous non-traumatic rupture of the thoracic aorta. Thorac Cardiovasc Surg 1994; 42: 355–7.

6. Ashcraft WC, McCallum T, Gullickson D, Fulton RL. Spontaneous rupture of the normal diameter atherosclerotic aorta. J Ky Med Assoc 1984; 82: 159–62.

7. Hirai S, Hamanaka Y, Mitsui N, Morifuji K, Uegami S. Spontaneous rupture of the ascending thoracic aorta resulting in a mimicking pseudoaneurysm. Ann Thorac Cardiovasc Surg 2006; 12: 223–7.

8. Stanson AW, Kazmier FJ, Hollier LH, Edwards WD, Pairolero PC, et al. Penetrating atherosclerotic ulcers of the thoracic aorta: natural history and clinico-pathologic correlations. Ann Vasc Surg 1986; 1: 15–23.

9. Braverman AC. Penetrating atherosclerotic ulcers of the aorta. Curr Opin in Cardiol 1994; 9: 591–7.