Asian Cardiovasc Thorac Ann 2002;10:354-355
© 2002 Asia Publishing EXchange Pte Ltd
Acute Descending Aortic Dissection Associated With Coarctation in Adult
Shin Jae Seung, MD,
Sun Kyung, MD,
Shim Wan Joo, MD1,
Kim Kwang Taik, MD,
Kim Hyoung Mook, MD
Department of Thoracic Cardiovascular Surgery
1 Department of Cardiology Korea University Medical College Seoul, Korea
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For reprint information contact: Sun Kyung, MD Tel: 82 2 920 5559 Fax: 82 2 927 3104 email: ksunmd{at}ns.kumc.or.kr Department of Thoracic and Cardiovascular Surgery, Korea University Medical College, 126-1 Anam-dong 5-ga, Sungbuk-gu, Seoul 136-705, Korea.
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ABSTRACT
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A 44-year-old man with congenital aortic coarctation experienced acute dissection that crossed the coarctation and extended to both iliac arteries. The primary entry of the dissection was proximal to the coarctation segment, just below the origin of the left subclavian artery. Surgical procedures involved resection of the diseased segment including the coarctation, and graft interposition.
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INTRODUCTION
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Congenital coarctation of the aorta is a known predisposing factor in aortic dissection. Most spontaneous dissections involve the ascending aorta and/or aortic arch (Stanford type A), whereas type B dissections involving the descending thoracic aorta are usually procedure-related (balloon angioplasty or surgical repair).1 The combination of spontaneous descending aortic dissection and adult coarctation is extremely rare.
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CASE REPORT
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A 44-year-old man presented with a substernal squeezing pain radiating to the back. He had a 20-year history of antihypertension medication. He had a normal body temperature, a respiratory rate of 24 breaths·min-1, and a regular heart rate of 60 beats·min-1. Blood pressure was 200/110 mm Hg in the right arm and 190/120 mm Hg in the left arm. Chest radiography showed a widened mediastinum, and electrocardiographic findings were nonspecific. Transesophageal echocardiography demonstrated a bicuspid aortic valve, a normal ascending aorta, and a dilated descending thoracic aorta (diameter, 66 mm) with a circumferential intimal flap. With suspected acute type B aortic dissection, the patient was initially treated with continuous nitroprusside and beta-blocker infusion. On the 6th day, severe back pain and hoarseness developed suddenly. Chest radiography showed increased widening of the mediastinal shadow, and contrast computed tomography demonstrated aortic dissection extending to both iliac arteries (Figure 1 
). The patient’s condition deteriorated and he underwent emergency surgery. Preoperative direct measurement of arterial pressures showed gradients between the right radial (150/100 mm Hg), left radial (140/100 mm Hg), and dorsalis pedis arteries (115/90 mm Hg). Under general anesthesia, the patient was placed in the right decubitus position, and the thorax was approached by a left thoracotomy through the 4th intercostal space. Aneurysmal dilatation with a maximal outer diameter of 7 cm was found to involve the entire descending thoracic aorta. The aneurysmal sac extended upward and completely obscured the mediastinal structures. Normothermic left heart bypass was instituted from the left atrium to the left femoral artery, and centrifugal pump flow was maintained at 2 to 3 L·min-1 under close observation of urine flow and arterial pressure in the dorsalis pedis artery. The proximal aorta and left subclavian artery were controlled with separate curved vascular clamps. On opening the aneurysmal sac, a 2-cm circumferential intimal tear was found just below the origin of the left subclavian artery. The false lumen involved the lower part of the left subclavian artery but not the arch vessels. Incidentally, a stenotic opening of the aortic lumen (diameter, 12 mm) was found distal to the intimal tear (Figure 2 ). The dissected segment including a coarctation of 10 cm in length was resected, and a 22-mm Dacron graft was interposed. The postoperative pressure difference between the radial artery and the dorsalis pedis artery was no different from the preoperative value.
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Figure 1. Preoperative chest computed tomography showing an expanded aortic wall with an intimal flap at the descending thoracic aorta.
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DISCUSSION
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A few cases of spontaneous type B aortic dissection associated with coarctation have been documented, however, they were independent of the coarctation or distal to the lesion.2–4 Turbulent blood flow across the aortic narrowing and associated congenital abnormalities of the aortic wall might lead to weakness and dissection of the aorta with post-stenotic dilatation. In this patient, the entry of the dissection was proximal to the coarctation, just below the left subclavian artery. The false lumen did not extend to the aortic arch, but interestingly, it crossed the coarctation segment and extended downward. Careful postoperative evaluation showed no evidence of connective tissue diseases or chromosomal anomalies.
Aortography or 3-dimensional chest tomography should indicate an associated coarctation.2,3 However, these techniques take time and may be unsuitable when the patient is hemodynamically unstable. We have adopted transesophageal echocardiography as the primary diagnostic tool for type B dissection in an unstable patient. Coarctation was not detected preoperatively in this case, thus preoperative aortography and 2-dimensional chest tomography do not always demonstrate coarctation associated with aortic dissection. A previous report also described coarctation identified during surgery for aortic dissection, despite extensive diagnostic studies.4
A pressure gradient between the upper and lower extremities may suggest aortic coarctation. However, as seen in this case of adult coarctation, the preoperative and postoperative pressure differences between the radial and dorsalis pedis arteries were similar; a preexisting rich collateral supply in adult coarctation might explain this. Although acute spontaneous type B aortic dissection associated with adult congenital coarctation is extremely rare, the surgical principles are no different from those of isolated descending aortic dissection. However, careful evaluation for accompanying systemic diseases or chromosomal anomalies is needed to identify Marfan or Turner’s syndrome.3,5
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REFERENCES
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- Beitzke A, Stein J-I, Gamillscheg A, Rigler B. Dissection of the descending aorta after balloon angioplasty of native coarctation. Pediatr Cardiol
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- Graeter T, Schaefer C, Prokop M, Laas J. Three-dimensional vascular imaging — an additional diagnostic tool. Thorac Cardiovasc Surgeon
1993;41:183–5.[Medline]
- Yamaguchi A, Adachi H, Kamio H, Murata S, Okada M, Adachi K, et al. A combination of preductal aortic coarctation and type B dissection: report of a case. Surg Today
1998;28:435–7.[Medline]
- Katsumata T, Westaby S. Operation for mid-arch coarctation. Ann Thorac Surg
1999;67:1386–90.[Abstract/Free Full Text]
- Lin AK, Lippe BM, Geffner ME. Aortic dilation, dissection, and rupture in patients with Turner’s syndrome. J Pediatr
1986;109:820–6.[Medline]
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ABSTRACT
INTRODUCTION
