Thoracic aortic aneurysm clinically pertinent controversies and uncertainties.

This paper addresses clinical controversies and uncertainties regarding thoracic aortic aneurysm and its treatment. 1) Estimating true aortic size is confounded by obliquity, asymmetry, and noncorresponding sites: both echocardiography and computed tomography/magnetic resonance imaging are necessary for complete assessment. 2) Epidemiology of thoracic aortic aneurysm. There has been a bona fide increase in incidence of aortic aneurysm making aneurysm disease the 18th most common cause of death. 3) Aortic growth rate. Although a virulent disease, thoracic aortic aneurysm is an indolent process. The thoracic aorta grows slowly-0.1 cm/year. 4) Evidence-based intervention criteria. It is imperative to extirpate the thoracic aorta before rupture or dissection occurs; surgery at 5.0- to 5.5-cm diameter will prevent most adverse natural events. Symptomatic (painful) aneurysms must be resected regardless of size. 5) Development of nonsize criteria. Mechanical properties of the aorta deteriorate at the same 6 cm at which dissection occurs; elastic properties of the aorta may soon become useful intervention criteria. 6) Medical treatment of aortic aneurysm. Medical treatment is of unproven value, even beta-blockers and angiotensin-receptor blockers. 7) A genetic disease. Even non-Marfan aneurysms have a strong genetic basis. 8) Need for biomarkers. Virulent but silent, TAA cries out for a biomarker that can predict the onset of adverse events. Pathophysiologic understanding has led to identification of promising biomarkers, especially metalloproteinases. 9) Endovascular therapy for aneurysms. Endovascular therapy has burgeoned, despite the fact that the EVAR-2, DREAM, and INSTEAD trials showed no benefit at mid-term over medical or conventional surgical therapy. We must avoid "irrational exuberance." 10) Inciting events for acute aortic dissection. Recent evidence shows that dissections are preceded by a specific severe exertional or emotional event. 11) "Silver lining" of aortic disease. Proximal aortic root disease seems to protect against arteriosclerosis.