In Acute ST-Segment Elevation Myocardial Infarction, Coronary Wedge Pressure Is Associated with Infarct Size and Reperfusion Injury as Evaluated by Cardiac Magnetic Resonance Imaging

Background. Coronary collateral flow influences patient prognosis in the setting of acute myocardial infarction. However, few data exist about the relation between coronary collaterals, infarct size, and reperfusion injury. The angiographic Rentrop score is prone to subjectivism and to the inherent limitations of angiographic images. Its prognostic value is controversial in the setting of acute myocardial infarction. The invasive measurement of coronary wedge pressure (CWP) represents an alternative to Rentrop score for the evaluation of coronary collateralization. Our study evaluates pre-revascularization CWP as a predictor of infarct size and reperfusion injury as evaluated by cardiac magnetic resonance imaging. Methods. Patients with acute ST-elevation myocardial infarction underwent preprocedural CWP measurement and primary percutaneous coronary intervention. Infarct size, microvascular obstruction, intramyocardial edema, and intramyocardial hemorrhage were evaluated by cardiac magnetic resonance imaging. Results. Mean CWP was inversely associated with infarct size (p = 0.01), microvascular obstruction (p = 0.02), intramyocardial edema (p = 0.05), and intramyocardial hemorrhage (p = 0.01). An excellent association was found between mean CWP and an infarct size >= 24% of left ventricular mass (AUC = 0.880, p = 0.007), with an optimal cutoff value <= 24.5 mmHg. Both intramyocardial edema (p = 0.02) and hemorrhage (p = 0.03) had a larger extent in patients with coronary wedge pressure <= 24.5 mmHg. Rentrop grade <2 was associated with larger infarct size (p = 0.03), but not with the extent of edema, microvascular obstruction, or intramyocardial hemorrhage. Conclusions. Pre-revascularization CWP was a predictor of infarct size and was significantly associated with a larger extent of intramyocardial edema and intramyocardial hemorrhage. Rentrop grade <2 was associated with a larger infarct size, but had no influence on reperfusion injury.