Relationship and prognostic value of microvascular obstruction and infarct size in ST-elevation myocardial infarction as visualized by magnetic resonance imaging.
BACKGROUND
Both infarct size and microvascular obstruction (MO) assessed by cardiac magnetic resonance imaging (CMR) are known to be predictors for adverse clinical outcome after ST-elevation myocardial infarction (STEMI). We hypothesized that a ratio of MO and infarct size (MO/infarct size) might be an even stronger predictor for outcome after STEMI, which has not been investigated yet.


METHODS
STEMI patients reperfused by primary angioplasty (n = 438) within 12 h after symptom onset underwent contrast-enhanced CMR at a median of 3 days (interquartile range [IQR] 2;4) after the index event. MO and infarct size were measured 15 min after intravenous gadolinium injection. Follow-up was conducted after 19 months (IQR 10;27). The primary end point was defined as a composite of death, non-fatal myocardial reinfarction and congestive heart failure (major adverse cardiac events [MACE]).


RESULTS
The extent of MO was only weakly correlated with infarct size (r = 0.21, p < 0.001). In a first multivariate analysis including extent of MO, infarct size, ejection fraction, end-systolic and end-diastolic volume, the extent of MO was independently associated with MACE (hazard ratio [HR] 1.03, 95%CI 1.02–1.05, p < 0.001). In a second multivariate analysis including MO/infarct size on top of the extent of MO, infarct size, ejection fraction, end-systolic and end-diastolic volume, MO/infarct size was identified as the strongest independent predictor for MACE (HR 2.22 [95%CI 1.60–3.08, p < 0.001]).


CONCLUSIONS
In contrast to infarct size, MO is associated with adverse clinical outcome after STEMI even after adjustment for other CMR parameters. However, MO/infarct size is a more powerful predictor for long-term outcome after STEMI than either parameter alone.
Department of Internal Medicine, Cardiology, University of Leipzig-Heart Center, Strümpellstr. 39, Leipzig, 04289, Germany. s-dw@gmx.net
Suzanne
S
de Waha
Steffen
S
Desch
Ingo
I
Eitel
Georg
G
Fuernau
Philipp
P
Lurz
Anja
A
Leuschner
Matthias
M
Grothoff
Matthias
M
Gutberlet
Gerhard
G
Schuler
Holger
H
Thiele
D000368:Aged; D015906:Angioplasty, Balloon, Coronary / Q000379:methods*; D015331:Cohort Studies; D005260:Female; D005500:Follow-Up Studies; D006333:Heart Failure / Q000453:epidemiology / Q000209:etiology*; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008833:Microcirculation; D008875:Middle Aged; D015999:Multivariate Analysis; D009203:Myocardial Infarction / Q000503:physiopathology* / Q000628:therapy; D011379:Prognosis; D011446:Prospective Studies; D016896:Treatment Outcome