Table II.

Patient subgroup definitions based on characteristics at randomization

•Age at randomization⁎ •Sex •Family history of aortic dissection in a first-degree family member (i) at any age and (ii) occurring in the family member at an age ≤40 y • The presence or absence of: ▪ ectopia lentis ▪ dural ectasia ▪ musculoskeletal involvement† •Aortic root dimension at the sinuses of Valsalva at enrollment, indexed to body surface area and expressed as a z-score‡ •Baseline age-adjusted imaging markers of arterial stiffness and elasticity •Presence and type of variants in genes encoding components of the extracellular matrix including fibrillin-1; the TGFβ pathway; the renin-angiotensin system; the β-adrenergic system; and pathways involved in the binding, transport, metabolism, or excretion of ARBs and/or β-blockers •Circulating biomarkers of vascular function (including TGFβ level where available) at baseline •Use of β-blockers at baseline •Use of calcium-channel blockers at baseline •Use of HMG CoA reductase inhibitors (statins) at baseline •Prior history of aortic root surgery at baseline •Systolic and diastolic blood pressure at baseline as a continuous measure§

^⁎Both the linear dependence of the absolute treatment effect on age and the separate effect of treatment allocation among patients aged ≤16 years versus >16 years will be assessed.

^†Defined as >4 major manifestations reaching a major criterion in the 1996 nosology.

^‡As a continuous measure and categorized as <4.5 versus ≥4.5.

^§As a continuous measure and categorized as <140 versus >140 systolic and <90 versus >90 diastolic.