Visualization of Discrete Microinfarction After Percutaneous Coronary Intervention Associated With Mild Creatine Kinase-MB Elevation

Abstract

Background-Mild elevations in creatine kinase-MB (CK-MB) are common after successful percutaneous coronary interventions and are associated with future adverse cardiac events. The mechanism for CK-MB release remains unclear.A new contrast-enhanced MRI technique allows direct visualization of myonecrosis. Methods and Results-Fourteen patients without prior infarction underwent cine and contrast-enhanced MRI after successful coronary stenting; 9 patients had procedure-related CK-MB elevation, and 5 did not (negative controls). The mean age of all patients was 61 years, 36% had diabetes, 43% had multivessel coronary artery disease, and all had a normal ejection fraction. Twelve patients (86%) received an intravenous glycoprotein IIb/IIIa inhibitor; none underwent atherectomy, and all had final TIMI 3 flow. Of the 9 patients with CK-MB elevation, 5 had a minor side branch occlusion during stenting, 2 had transient ECG changes, and none developed Q-waves. The median CK-MB was 21 ng/mL (range, 12 to 93 ng/mL), which is 2.3ϫ the upper limit of normal. Contrast-enhanced MRI demonstrated discrete regions of hyperenhancement within the target vessel perfusion territory in all 9 patients. Only one developed a new wall motion abnormality. The median estimated mass of myonecrosis was 2.0 g (range, 0.7 to 12.2 g), or 1.5% of left ventricular mass (range, 0.4% to 6.0%). Hyperenhancement persisted in 5 of the 6 who underwent a repeat MRI at 3 to 12 months. No control patient had hyperenhancement. Conclusions-Contrast-enhanced MRI provides an anatomical correlate to biochemical evidence of procedure-related myocardial injury, despite the lack of ECG changes or wall motion abnormalities. Mild elevation of CK-MB after percutaneous coronary intervention is the result of discrete microinfarction.

Persistent decline in longitudinal and radial strain after coronary microembolization detected on velocity encoded phase contrast magnetic resonance imaging

“…Characterization of microinfarction in patients has previously been performed with cine and DE-MRI (1,3,26). This study provides additional characterization of coronary microembolization by adding strain measurements by PC-MRI for evaluation of discrete microinfarction and demonstrating a direct link between microembolization and LV dysfunction.…”

“…MICROEMBOLIZATION IS A COMMON clinical problem, occurring in almost one fourth of the vast patient population who undergo coronary intervention (1)(2)(3)(4). The wide variation in size (47-2503 m) of emboli shed in these procedures has been directly measured (5,6) and their detrimental consequences are noted in the 2007 guidelines of the American College of Cardiology and of the European Society of Cardiology (4).…”

Detection of myocarditis by contrast‐enhanced MRI in patients presenting with acute coronary syndrome but no coronary stenosis

“…Most patients without myocarditis pattern were likely to have an ischemic injury, as supported by their higher risk for coronary disease, the frequent presence of rest-SPECT defects and of typical DCE pattern of ischemic necrosis (15)(16)(17)(18)40). The lack of relevant coronary angiographic finding in these patients might relate to the systematic antithrombotic therapy prior to coronary angiography or to the possible occlusion of a small coronary branch, inaccessible to visual angiographic examination, as suggested by the limited extent of DCE areas (6 Ϯ 4% of LV).…”

“…MRI with delayed contrast enhancement (DCE) allows visualization of small myocardial injuries that cannot be detected by any other noninvasive technique (15,16). DCE identifies acute or chronic myocardial infarction even when restricted to small subendocardial areas (17,18).…”

Myocardial Damage Detected by Late Gadolinium Enhancement Cardiac Magnetic Resonance Is Uncommon in Peripartum Cardiomyopathy

“…LGE can detect foci of myocardial damage as small as 0.7 g of myocardial tissue 28. In the absence of coronary artery disease associated with ischemic cardiomyopathy,29 LGE can likely detect myocardial damage associated with vasospasm, embolization, cocaine, or recanalized myocardial infarction 30…”