TABLE 3.

Association of Baseline Aortic Stiffness with Composite Outcome Adjusted for Age and Maximum Aortic-Root Z-Score

Baseline Predictors	#Events/Group n	Crude 3-year Event Rate (95% Confidence Interval)	Adjusted Hazard Ratio (95% Confidence Interval)	Main Effect p value	Interaction with Age p value	Interaction with Maximum Aortic Root z score p value
AORTIC ROOT
Elastic Modulus
>618 vs. ≤618 mm Hg (median)	22/299 vs. 7/299	7.6% (5.1 to 11.4) vs. 2.4% (1.1 to 5.0)	2.61 (1.01, 6.76)	0.05	0.77	0.04†
>914 vs. ≤914 mm Hg (75th percentile)	15/150 vs. 14/448	10.4% (6.4 to 16.7) vs. 3.2% (1.9 to 5.4)	2.17 (1.02, 4.63)	0.04	0.96	0.12
Heart Rate-Adjusted* Stiffness Index
>9.1 vs. ≤9.1 (median)	20/310 vs. 8/285	6.6% (4.3 to 10.0) vs. 2.9% (1.5 to 5.7)	2.29 (0.95, 5.52)	0.07	0.70	0.03§
>13.7 vs. ≤13.7 (75th percentile)	10/149 vs. 18/446	6.9% (3.8 to 12.5) vs. 4.2% (2.6 to 6.5)	1.40 (0.64, 3.07)	0.40	0.31	0.48
ASCENDING AORTA
Elastic Modulus
>318 vs. ≤318 mm Hg (median)	17/246 vs. 4/246	7.2% (4.5 to 11.2) vs. 1.7% (0.6 to 4.4)	1.97 (0.62, 6.28)	0.25	0.53	0.72
>447 vs. ≤447 mm Hg (75th percentile)	9/123 vs. 12/369	7.5% (4.0 to 13.9) vs. 3.4% (1.9 to 5.8)	2.40 (0.92, 6.28)	0.08	0.20	0.20
Heart Rate-Adjusted* Stiffness Index
>4.7 vs. ≤4.7 (median)	14/239 vs. 6/251	6.0% (3.6 to 9.9) vs. 2.5% (1.1 to 5.4)	1.61 (0.60, 4.33)	0.34	0.98	0.46
>6.6 vs. ≤6.6 (75th percentile)	8/124 vs. 12/366	6.6% (3.3 to 12.7) vs. 3.4% (1.9 to 5.9)	2.28 (0.88, 5.89)	0.09	0.27	0.05

Composite Outcome: Aortic-Root Surgery, Dissection, Death

^*divided by the square root of R-R interval

^†Interaction p=0.04: Adjusted Hazard Ratios vary with maximum aortic root z score (Max ARz), Hazard Ratio=0.93 at MaxARz=3.0; Hazard Ratio=1.50 at Max ARz=4.5; Hazard Ratio=2.43 at Max ARz=6.0

^§Interaction p=0.03: Adjusted Hazard Ratios vary with Max ARz, Hazard Ratio=0.81 at MaxARz=3.0; Hazard Ratio=1.38 at Max ARz=4.5; Hazard Ratio=2.35 at Max ARz=6.0