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Coady MA, Rizzo JA, Hammond GL, Mandapati D, Darr U, Kopf GS, Elefteriades JA. What is the appropriate size criterion for resection of thoracic aortic aneurysms? J Thorac Cardiovasc Surg. 1997;113(3):476-91. PMID 9081092

One-paragraph summary

First systematic natural-history analysis of the Yale TAA database: 230 patients, 714 serial imaging studies (MRI/CT/echo), 1985–1996. Mean aortic size at presentation 5.2 cm (range 3.5–10); mean growth 0.12 cm/yr. Median size at rupture or dissection was 6.0 cm for ascending and 7.2 cm for descending aneurysms, and incidence of complications rose sharply with size: multivariable regression showed size >6.0 cm raised the probability of dissection/rupture by 32.1 percentage points for ascending aneurysms (p = 0.005) and >7.0 cm by 43.0 points for descending (p = 0.006) — the "hinge points." Overall survival 85% at 1 yr and 64% at 5 yr; elective operative mortality 9.0% vs 21.7% emergency. The authors argued that waiting for the median-complication size condemns half of patients to complication first, and recommended elective resection at 5.5 cm (ascending) and 6.5 cm (descending).

Key findings

  • Hinge points: ascending >6.0 cm → +32.1 percentage-point probability of rupture/dissection; descending >7.0 cm → +43.0 points.
  • Median size at complication: 6.0 cm ascending, 7.2 cm descending; therefore criteria must sit below the median (5.5 / 6.5 cm proposed).
  • Mean growth 0.12 cm/yr in the aneurysmal thoracic aorta.
  • Elective vs emergency operative mortality: 9.0% vs 21.7% — the arithmetic case for preemptive surgery.
  • Dissection carried worse survival (1-yr 83%, 5-yr 46%) than non-dissected disease (89%, 71%).

Limitations

  • Single referral center; selection and referral bias toward larger/complex aortas.
  • Retrospective; imaging across three modalities without a unified measurement protocol (see wiki/anatomy-and-classification.md on inter-modality discrepancy).
  • Complication probabilities estimated cross-sectionally by attained size, not per-year hazards (that step came with Davies 2002, PMID 11834007).
  • Modest event counts at the extremes of size; syndromic and non-syndromic patients pooled.

Why it matters

This paper converted TAA surgery from eminence-based to evidence-based sizing: it introduced the hinge-point concept, established the ascending/descending asymmetry (6 vs 7 cm), and set the 5.5 cm elective criterion that guideline thresholds have orbited ever since. Nearly every subsequent debate — indexed size, the aortic size paradox, lowering thresholds — is an argument with this paper's framework.

Cited by wiki pages

  • overview
  • epidemiology-and-natural-history
  • aortic-dissection