Surgical thresholds for aortic root and/or ascending aortic replacement in heritable thoracic aortic aneurysm disease*
| Heritable condition | Size threshold for aortic root and/or ascending aortic surgery |
| Marfan syndrome17–19 | ≥50 mm |
| >45 mm (with risk factors)† | |
| Loeys-Dietz syndrome17 22 | |
| TGFBR1, TGFBR2, SMAD3 | 40–45 mm‡ |
| TGFB2 | ≥45 mm‡ (limited information) |
| TGFB3 | ?>45–50 mm (limited information) |
| nsHTAD | |
| ACTA2 | ≥45 mm |
| PRKG2, MYH11 | ≥45 mm |
| MYLK | ? aortic dissection may occur without significant aortic dilatation |
| Bicuspid aortic valve48 | ≥55 mm |
| ≥50 mm (with risk factors/low surgical risk)§ | |
| >45 mm (requiring aortic valve replacement) |
*Specific pathogenic variants may associate with a higher risk of aortic events. A family history of aortic dissection may inform earlier surgery for other family members.
†Family history of aortic dissection or aortic growth rate >3 mm/year, severe aortic or mitral regurgitation, or before pregnancy.
‡Surgery at the smaller aortic diameters may be considered for individuals with severe craniofacial features, marked arterial tortuosity, widened scars, younger individuals (especially women with TGFBR2 pathogenic variants and small body size), rapid aortic growth (>3 mm/year) or family history of aortic dissection (especially at small aortic size). In non-syndromic HTAD due to TGF-β genes, surgical thresholds may be at larger aortic diameters depending on age, family history, aortic growth rate and other features.
§Presence of family history of aortic dissection; or aortic growth rate of >3–5 mm/year; or with coarctation of the aorta; or can be performed at low surgical risk (<4%) with surgery performed at an experienced aortic surgical centre. Surgery is recommended before pregnancy when aortic size is ≥50 mm and shared decision making is recommended when the aorta is 45–49 mm.
HTAD, heritable thoracic aortic disease; ns, nonsyndromic.