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Key Concepts

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  • Epidemiology

    • Thoracoabdominal aneurysms (TAAs) develop in patients with atherosclerotic disease, chronic aortic dissection, and connective tissue disorders (e.g., Marfan syndrome, Ehler–Danlos syndrome).

  • Pathophysiology

    • Pathologic processes include chronic inflammation, remodeling of extracellular matrix, and depletion of vascular smooth muscle cells. Elastin depletion in the media layer of the aortic wall is a common finding.

  • Clinical features

    • Approximately 80 percent of TAAs are atherosclerotic in nature, associated with smoking, hypertension, hypercholesterolemia, and advanced age. Approximately 20 percent of TAAs develop from chronic aortic dissections and occur in patients with connective tissue disorders. The risk of rupture increases rapidly when aneurysmal diameter reaches or exceeds 6 cm. The most common presentation includes abdominal or back pain, although many TAAs are also discovered incidentally.

  • Diagnostics

    • TAAs are classified commonly according to the anatomic scheme developed by Crawford (types I through V). Helical computed tomography and magnetic resonance angiography are the diagnostic modalities of choice, largely having supplanted angiography.

  • Treatment

    • Medical therapy includes the reduction of risk factors for aneurysmal expansion (e.g., smoking, hypercholesterolemia) and tight blood pressure control predicated on the use of β-blockers.

    • Interventional therapy includes open surgical, hybrid and totally endovascular repair. Spinal cord protection is of particular concern in all methods of repair.

  • Outcomes

    • In-hospital mortality rates after surgery range between 8 and 15 percent in most series. Common postoperative complications include bleeding, respiratory failure, myocardial infarction or cardiac failure, renal failure, and paraplegia. Operative risk increases with advanced age, aneurysm complexity, emergency operation, coronary and cerebrovascular disease, pulmonary disease, and renal failure. Outcomes may be improved with the distal perfusion approach to repair. Five-year survival rates range between 53 and 73 percent.

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Introduction

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Since its introduction by Michael DeBakey in 1956,1 thoracoabdominal aneurysm (TAA) repair generally presents the most technically challenging and controversial issues in vascular surgery. The surgical repair of TAAs is an undertaking that requires substantial preoperative planning and consideration of a wide array of techniques. Each of these techniques has its champions, and several authors have published comparably good results using widely different methods. In this chapter, the common principles that are applicable to all TAA surgery are described. In addition, most of the surgical techniques currently in use to repair these aneurysms are discussed, with emphasis on those that are preferred at the Johns Hopkins Hospital.

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Pathophysiology

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Insight into the pathophysiology of aortic aneurysm formation at the cellular level has come into focus only recently. The pathologic processes observed in aneurysm development include chronic inflammation, remodeling of the extracellular matrix, and depletion of vascular smooth muscle cells. A basic feature common to all aneurysms is the depletion of elastin, a key structural protein in the media layer of the aortic wall. Normal turnover of matrix proteins is mediated by a family of enzymes called matrix metalloproteinases (MMPs); their activity is regulated by proteins called tissue inhibitors of metalloproteinases (TIMPs). Several MMPs have ...

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