Relationship between CMR-derived parameters of ischemia/reperfusion injury and the timing of CMR after reperfused ST-segment elevation myocardial infarction.

BACKGROUND

To investigate the influence of cardiovascular magnetic resonance (CMR) timing after reperfusion on CMR-derived parameters of ischemia/reperfusion (I/R) injury in patients with ST-segment elevation myocardial infarction (STEMI).

METHODS

The study included 163 reperfused STEMI patients undergoing CMR during the index hospitalization. Patients were divided according to the time between revascularization and CMR (Trevasc-CMR: Tertile-1 ≤ 43; 43 < Tertile-2 ≤ 93; Tertile-3 > 93 h). T2-mapping derived area-at-risk (AAR) and intramyocardial-hemorrhage (IMH), and late gadolinium enhancement (LGE)-derived infarct size (IS) and microvascular obstruction (MVO) were quantified. T1-mapping was performed before and > 15 min after Gd-based contrast-agent administration yielding extracellular volume (ECV) of infarct.

RESULTS

Main factors influencing I/R injury were homogenously balanced across Trevasc-CMR tertiles. T2 values of infarct and remote regions increased with increasing Trevasc-CMR tertiles (infarct: 60.0 ± 4.9 vs 63.5 ± 5.6 vs 64.8 ± 7.5 ms; P < 0.001; remote: 44.3 ± 2.8 vs 46.1 ± 2.8 vs ± 46.1 ± 3.0; P = 0.001). However, T2 value of infarct largely and significantly exceeded that of remote myocardium in each tertile yielding comparable T2-mapping-derived AAR extent throughout Trevasc-CMR tertiles (17 ± 9% vs 19 ± 9% vs 18 ± 8% of LV, respectively, P = 0.385). Similarly, T2-mapping-based IMH detection and quantification were independent of Trevasc-CMR. LGE-derived IS and MVO were not influenced by Trevasc-CMR (IS: 12 ± 9% vs 12 ± 9% vs 14 ± 9% of LV, respectively, P = 0.646). In 68 patients without MVO, T1-mapping based ECV of infarct region was comparable across Trevasc-CMR tertiles (P = 0.470).

CONCLUSION

In STEMI patients, T2 values of infarct and remote myocardium increase with increasing CMR time after revascularization. However, these changes do not give rise to substantial variation of T2-mapping-derived AAR size nor of other CMR-based parameters of I/R.

TRIAL REGISTRATION: ISRCTN03522116 . Registered 30.4.2018 (retrospectively registered).