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Acute Aortic Disease.. - Index of

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Natural History <strong>of</strong> Thoracic <strong>Aortic</strong> Aneurysms 203<br />

We have seen an abstract on this topic, but not a subsequent paper. There is no<br />

question that dissection can occur at small sizes. In our studies <strong>of</strong> weight lifters<br />

suffering aortic dissection (see Chapter 10), most young men dissected at a dimension<br />

between 4 and 5 cm. We feel these individuals imposed an extreme blood<br />

pressure stress (likely above 300 mmHg) on their aortas. We know (see Chapter 7)<br />

that wall stress depends on both aortic size and blood pressure. <strong>Aortic</strong> dissection<br />

at small sizes does, additionally, occur in nonweight lifters. Here one must keep<br />

in mind how huge is the denominator <strong>of</strong> patients with aortas in this size range.<br />

If aortic dimension follows a bell curve, like most physical traits, the number <strong>of</strong><br />

patients must increase immensely as one comes back from the tails <strong>of</strong> the curve.<br />

Our feeling is that there are so many (probably millions) <strong>of</strong> patients with aortas<br />

<strong>of</strong> size 4 cm or more that the observed cases <strong>of</strong> dissection at these sizes represent<br />

a very low percentage. This is certainly the case in our careful follow-up <strong>of</strong> patients<br />

with known aortic size, whose percentage likelihood <strong>of</strong> dissection is represented<br />

in the figures and tables in this chapter. The likelihood <strong>of</strong> dissection in this population<br />

under direct observation is very low. In fact, once a patient has entered our<br />

system, and a decision made for medical management because <strong>of</strong> lack <strong>of</strong> symptoms<br />

and small aortic size, we are not aware <strong>of</strong> any instances <strong>of</strong> aortic dissection<br />

under such observation. We are now looking at this phenomenon from a heuristic,<br />

decision-making standpoint, to determine precisely how many patients may<br />

dissect when our recommended algorithms are applied. In short, we are not aware<br />

<strong>of</strong> a means to apply clinically the observation that some patients dissect at very<br />

small sizes. To operate prophylactic on all patients with minor enlargement <strong>of</strong> the<br />

aorta (say those with aortas between 4 and 5 cm) would probably cause more<br />

harm (surgical) than good.

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