Clinical Outcomes Associated With Various Microvascular Injury Patterns Identified by CMR After STEMI
Key result
Post-STEMI intramyocardial hemorrhage on CMR predicts ~288% higher MACE risk, unlike microvascular obstruction alone.
- HR 3.88
- 95% CI 1.93-7.80
- P<0.001
- n=1,109
Why the study?
The prognostic significance of various microvascular injury patterns after STEMI is not well known.
Population
1,109 STEMI patients included in 3 prospective studies
Comparison
MVO-/IMH- vs MVO+/IMH- vs IMH+
Design
Pooled analysis of 3 prospective studies
Follow-up
Median 12 months (Q1-Q3: 12-35 months)
Authors
Discussion
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Implication
May refine post-STEMI prognostication via CMR-detected IMH; leaves open routine use pending further trials.
Key Points
- To evaluate the prognostic significance of distinct microvascular injury patterns, specifically microvascular obstruction and intramyocardial hemorrhage, after ST-segment elevation myocardial infarction (STEMI).
- Analyzed 1,109 STEMI patients from 3 prospective studies who underwent percutaneous coronary intervention (PCI).
- Performed cardiac magnetic resonance (CMR) at a median of 3 days (Q1-Q3: 2-5 days) post-PCI using late gadolinium enhancement to detect microvascular obstruction (MVO) and T2* mapping to identify intramyocardial hemorrhage (IMH).
- Stratified patients into three phenotypes: no microvascular injury (MVO-/IMH-), MVO without hemorrhage (MVO+/IMH-), and intramyocardial hemorrhage (IMH+), with a median follow-up of 12 months (Q1-Q3: 12-35 months).
- Microvascular injury occurred in 57% (633/1,109) of patients, with 25% (274/1,109) exhibiting MVO+/IMH- and 32% (359/1,109) exhibiting IMH+.
- Infarct size was significantly larger (27% vs 19% vs 18%, P < 0.001) and ejection fraction significantly lower (45% vs 50% vs 54%, P < 0.001) in IMH+ compared with MVO+/IMH- and MVO-/IMH-.
- Adverse clinical events occurred in 19.5% of IMH+ patients compared to 3.6% in MVO+/IMH- and 4.4% in MVO-/IMH- (P < 0.001), with IMH+ serving as the sole independent predictor of major adverse cardiovascular events (HR: 3.88; 95% CI: 1.93-7.80; P < 0.001).
Study Design
Type
Cohort (n=1,109)
PICO
P
Population
ST-segment elevation myocardial infarction (STEMI) (n=1,109)
I
Intervention / Comparator
Intramyocardial hemorrhage (IMH+) pattern on CMR vs Microvascular obstruction without IMH (MVO+/IMH-) or no microvascular injury (MVO-/IMH-)
O
Primary Outcome
Major adverse cardiovascular events — HR 3.88 (1.93-7.80), p=<0.001
Main Result
Effect estimate: HR 3.88 (95% CI 1.93-7.80)
p-value: p=<0.001
Cite This Study
Lechner et al. (2024) conducted a cohort in ST-segment elevation myocardial infarction (STEMI) (n=1,109). Intramyocardial hemorrhage (IMH+) pattern on CMR vs. Microvascular obstruction without IMH (MVO+/IMH-) or no microvascular injury (MVO-/IMH-) was evaluated on Major adverse cardiovascular events (HR 3.88, 95% CI 1.93-7.80, p=<0.001). Intramyocardial hemorrhage (IMH+) identified by CMR after STEMI independently predicted major adverse cardiovascular events (HR 3.88; 95% CI 1.93-7.80; P<0.001), unlike microvascular obstruction alone.