Table 2.
Comparison of CMR Findings at Baseline (n = 288) and at 6 Months (n = 267) in Patients With STEMI Grouped According to Tertiles of Remote Zone Native T1 Values (ms) at Baseline
| All Patients | STEMI Patient Group in Tertiles, Remote Zone Native T1 at Baseline |
p Value | |||
|---|---|---|---|---|---|
| ≤951 ms (n = 96) | >951 to ≤969 ms (n = 96) | >969 ms (n = 96) | |||
| CMR findings 2 days post-MI (n = 288) | |||||
| LV ejection fraction, % | 55 ± 10 | 56 ± 10 | 56 ± 9 | 53 ± 10 | 0.041 |
| LV end-diastolic volume, ml | |||||
| Men | 162 ± 33 | 158 ± 29 | 158 ± 35 | 172 ± 34 | 0.017 |
| Women | 124 ± 25 | 117 ± 25 | 131 ± 25 | 124 ± 25 | 0.233 |
| LV end-systolic volume, ml | |||||
| Men | 76 ± 26 | 70 ± 23 | 72 ± 26 | 87 ± 27 | <0.001 |
| Women | 55 ± 18 | 52 ± 19 | 59 ± 17 | 53 ± 17 | 0.476 |
| LV mass, g | |||||
| Men | 144 ± 30 | 140 ± 28 | 142 ± 28 | 152 ± 33 | 0.054 |
| Women | 99 ± 24 | 93 ± 25 | 108 ± 25 | 96 ± 22 | 0.064 |
| Edema and infarct characteristics | |||||
| Area at risk, % of LV mass | 32 ± 12 | 29 ± 12 | 32 ± 12 | 35 ± 11 | 0.045 |
| Infarct size, % of LV mass | 18 ± 13 | 16 ± 13 | 17 ± 13 | 20 ± 14 | 0.044 |
| Myocardial salvage, % of LV mass | 19 ± 9 | 18 ± 9 | 20 ± 9 | 18 ± 8 | 0.370 |
| Myocardial salvage index, % of LV mass | 63 ± 24 | 68 ± 26 | 64 ± 23 | 57 ± 23 | 0.013 |
| Late microvascular obstruction present | 145 (50) | 41 (43) | 51 (53) | 53 (55) | 0.192 |
| Late microvascular obstruction, % of LV mass | 2.7 ± 4.6 | 1.6 ± 3.3 | 3.5 ± 5.4 | 3.2 ± 4.8 | 0.021 |
| Myocardial native T1 values | |||||
| T1 remote myocardium (all participants), ms | 961 ± 25 | 935 ± 12 | 960 ± 6 | 988 ± 17 | <0.001 |
| Men, ms | 959 ± 25 | 935 ± 12 | 960 ± 6 | 988 ± 17 | <0.001 |
| Women, ms | 968 ± 25 | 938 ± 11 | 961 ± 6 | 989 ± 18 | <0.001 |
| T1 infarct zone, ms | 1,097 ± 52 | 1,077 ± 44 | 1,100 ± 52 | 1,115 ± 52 | <0.001 |
| T1 hypointense core present | 160 (56) | 50 (52) | 52 (54) | 58 (60) | 0.483 |
| T1 hypointense infarct core, ms | 997 ± 57 | 986 ± 51 | 1,001 ± 64 | 1,003 ± 56 | 0.269 |
| CMR findings 6 months post-MI (n = 267) | |||||
| LV ejection fraction at 6 months, % | 62 ± 9 | 64 ± 8 | 63 ± 8 | 60 ± 11 | 0.010 |
| LV end-diastolic volume at 6 months, ml | |||||
| Men | 168 ± 37 | 160 ± 32 | 163 ± 32 | 182 ± 43 | 0.007 |
| Women | 128 ± 29 | 125 ± 20 | 128 ± 30 | 128 ± 33 | 0.995 |
| LV end-systolic volume at 6 months, ml | |||||
| Men | 66 ± 30 | 58 ± 21 | 63 ± 24 | 82 ± 39 | <0.001 |
| Women | 46 ± 17 | 46 ± 16 | 48 ± 19 | 45 ± 18 | 0.895 |
Values are mean ± SD or n (%). Area at risk was measured with T2 mapping. p values were obtained from 1-way analysis of variance, Kruskal-Wallis test, or Fisher test. Three T1 maps (basal-, mid-, and distal-ventricular levels) were measured in each patient (n = 876 T1-maps overall), and 93% of these maps were suitable for analysis. Overall, 20 patients (6.8%) had poor-quality T1 maps and 4 patients (1.3%) had no evaluable T1 maps (Figure 1). Forty-two T1 maps were unsuitable for analysis because of steady-state free precession off-resonance artifacts, and 19 of these T1 maps were also affected by motion artifacts. Remote zone native T1 values were higher than T1 values in infarct tissue (p < 0.001) and in infarct core (p < 0.001).
LV = left ventricular; MI = myocardial infarction; other abbreviations as in Table 1.