Table 4.

Characteristics of Patients Stratified According to iECV Thresholds and Presence of Mid-Wall Late Gadolinium Enhancement

	Normal Myocardium (n = 71)	Extracellular Expansion (n = 31)	Replacement Fibrosis (n = 37)	p Value
Age, yrs	70 (63−75)	70 (63−75)	71 (65−78)	0.59
Sex (male = 1)	0.56 (0.44−0.68)	0.81 (0.67−0.96)	0.76 (0.62−0.90)	0.023
Hypertension	48 (68)	20 (65)	22 (59)	0.70
Diabetes	8 (11)	7 (23)	2 (5)	0.09
Body mass index, kg/m2	28.2 ± 4.5	28.9 ± 4.6	29.3 ± 4.3	0.44
Echocardiography
Peak aortic jet velocity, m/s	3.53 ± 0.82	3.79 ± 1.0	4.23 ± 0.92	<0.001
Aortic valve area, cm2	0.98 (0.73−1.18)	0.88 (1.2−0.7)	0.83 (0.73−0.91)	0.049
Mean AV pressure gradient, mm Hg	29.1 ± 14.2	34.8 ± 21.1	41.1 ± 23.5	0.007
Mild AS	24	7	2
Moderate AS	18	10	11
Severe AS	29	14	24
Valvulo-arterial impedance, mm Hg/ml/m2	4.1 ± 1.0	3.9 ± 0.9	4.0 ± 1.0	0.46
Mean e', cm/s	6.7 ± 2.0	6.5 ± 1.8	5.2 ± 1.4	0.0004
Mean E/e' ratio	13.1 ± 7.7	13.2 ± 4.8	16.5 ± 6.5	0.04
Mean diastolic dysfunction grade	1.5 ± 0.9	2.0 ± 0.9	2.7 ± 0.5	<0.0001
CMR
LVMi, g/m2	73 ± 11	96 ± 11	107 ± 25	<0.0001
Relative wall thickness	0.60 ± 0.12	0.61 ± 0.09	0.67 ± 0.11	0.018
ECVi, ml/m2	18.3 ± 2.5	25.4 ± 3.1	30.4 ± 8.2	<0.0001
Ejection fraction, %	68 (63−71)	66 (64−71)	67 (64−72)	0.94
Longitudinal systolic function, mm	13.2 ± 2.6	12.5 ± 2.4	11.2 ± 3.1	0.002
Indexed left atrial volume, ml/m2	31 ± 13	37 ± 11	38 ± 15	0.027
Biomarkers
Natural log (hs troponin I)	1.43 ± 0.96	2.02 ± 0.93	2.60 ± 0.90	<0.0001
Natural log (BNP)	2.95 ± 1.00	3.06 ± 0.96	3.41 ± 1.10	0.12
Functional status
6-min walk test, m	406 ± 74	385±95	359 ± 138	0.08
NYHA functional class
I	33 (46)	18 (58)	17 (46)
II	27 (38)	6 (19)	12 (32)
III	11 (15)	7 (23)	5 (14)
IV	0 (0)	0 (0)	3 (8)
Outcomes
All-cause mortality	2	4	8	—
All-cause mortality rate (per 1,000 patient-yrs)	8	36	71	0.009
AS-related mortality, n	0	4	6	—
AS-related mortality rate (per 1,000 patient-yrs)	0	36	52	0.0045

Patients Undergoing Myocardial Biopsy	Normal Myocardium on CMR (n = 3)	Extracellular Expansion on CMR (n = 5)	Replacement Fibrosis on CMR (n = 3)	p Value
Histological fibrosis, %	8.9 ± 4.0	12.4 ± 2.5	22.4 ± 4.9	0.004
Aortic valve area, cm2	0.57 ± 0.10	0.94 ± 0.29	0.81 ± 0.44	0.29
Peak aortic jet velocity, m/s	4.6 (4.4−5.1)	4.5 (4.0−5.9)	4.9 (4.1−8.0)	0.63
LVMi, g/m2	76 ± 15	98 ± 4	162 ± 6	<0.0001
Native myocardial T1, ms	1,189 ± 23	1,183 ± 16	1,277 ± 15	0.0002
Post-contrast myocardial T1, ms	676 ± 45	615 ± 24	672 ± 84	0.22
Partition coefficient	0.43 ± 0.05	0.47 ± 0.02	0.55 ± 0.02	0.008
ECV fraction, %	25.3 ± 3.1	27.3 ± 1.4	32.2 ± 1.9	0.019
iECV, ml/m2	18.8 ± 1.9	25.6 ± 0.7	49.6 ± 4.8	<0.0001

Values are median (interquartile range), n (%), or mean ± SD.

Abbreviations as in Tables 1, 2, and 3.