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Acute Aortic Disease.. - Index of

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186 Coady and Elefteriades<br />

Figure 7 Key natural history graphs from the Yale database. (A) Survival <strong>of</strong> patients with<br />

unrepaired thoracic aortic aneurysm compared to that <strong>of</strong> the age and sex-matched general<br />

population. (B) Poorer outlook <strong>of</strong> patients with descending compared to ascending thoracic<br />

aortic aneruysm. (C) Adverse impact <strong>of</strong> aortic dissection on outlook. (D) Larger aneurysms<br />

do more poorly in the long run. (E) Elective surgical therapy is very safe, and restores<br />

excellent long-term prognosis. Source: From Ref. 1.<br />

indeed a lethal disease, but that it takes years for this lethality to express itself.<br />

Please note that it is not until after three years <strong>of</strong> follow-up, even in the largest<br />

aneurysms, that the survival curve drops significantly. Figure 7E demonstrates<br />

the excellent survival after elective surgical therapy for TAA. Note that emergent<br />

surgical therapy leads to much poorer long-term survival.<br />

These graphs argue strongly for elective, prophylactic surgical extirpation<br />

<strong>of</strong> the aneurysmal thoracic aortic aorta, before rupture or dissection—which either<br />

result in death or require emergent surgery—have a chance to occur.<br />

<strong>Aortic</strong> Growth<br />

Our team has found that calculation <strong>of</strong> growth rate is more complicated than simply<br />

subtracting original size from current size and dividing by time. Rizzo (52), from<br />

the Yale School <strong>of</strong> Public Health, has developed exponential equations that permit<br />

rigorous calculation <strong>of</strong> growth rates for large populations <strong>of</strong> TAA patients.<br />

Growth rate estimates were obtained for our entire population and for subgroups<br />

with specific risk factors by means <strong>of</strong> a multivariable regression analysis<br />

in which aneurysm growth followed an exponential path. In particular, the natural<br />

logarithm <strong>of</strong> the difference between the last measured size and the first measured

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