Magnetic resonance imaging quantification of left ventricular dysfunction following coronary microembolization

Abstract

Microembolization is common after coronary interventions, and therefore this MRI study aimed to quantify the effect of coronary microembolization on left ventricular (LV) function. The left anterior descending artery (LAD) was selectively catheterized in an XMR suite (Philips Medical Systems, Best, The Netherlands) in eight pigs to deliver MR contrast media to measure the LAD territory using first-pass perfusion and for intracoronary delivery of the embolic agent. Cine, tagged, and delayed contrastenhanced MRI (DCE-MRI) was performed to assess LV volumes, ejection fraction, radial and circumferential strain, and viability at baseline, 1 h, and 1 week after microembolization. Histopathology and histochemical staining were used to characterize and measure the extent of microinfarction. The LAD territory was 35% ؎ 2% LV mass. Patchy microinfarction on DCE-MRI at 1 week was 22.0% ؎ 3.6% LAD territory (7.5% LV mass). Microembolization caused persistent decline in ejection fraction (baseline ‫؍‬ 49% ؎ 1%, 1 h ‫؍‬ 29% ؎ 1%, P ‫؍‬ 0.02 and 1 week ‫؍‬ 36% ؎ 1%, P ‫؍‬ 0.03) and increased end-diastolic (79.6 ؎ 3.9 ml, 85.5 ؎ 4.5 ml, P ‫؍‬ 0.03 and 92.4 ؎ 6.2 ml, P ‫؍‬ 0.06, respectively) and end-systolic (40.8 ؎ 2.1 ml, 60.2 ؎ 3.4 ml, P ‫؍‬ 0.02 and 59.3 ؎ 4.8 ml, P ‫؍‬ 0.03, respectively) volumes. The microembolized territory was manifested as dysfunctional regions for 1 week on cine and tagged MRI. Histopathology revealed occlusive microemboli surrounded by necrotic tissue undergoing repair. Microinfarction was visualized after coronary microembolization and caused LV dysfunction disproportionate to the size of myocardial damage. It also changed LV geometry and decreased radial and circumferential strain over the course of 1 week. Magn Reson Med 61:595-602, 2009.

Heterogeneous Microinfarcts Caused by Coronary Microemboli: Evaluation with Multidetector CT and MR Imaging in a Swine Model

“…Eight adult healthy farm pigs (mean weight, 33 kg 6 1 [standard error of the mean ]) were anesthetized with a mixture of 2%-5% isofl urane and oxygen at a rate of 2-3 L/min, as described previously ( 8,9 ). Two animals died within 24 hours after delivery of the embolic materials.…”

“…Microinfarcts are defi ned as bright heterogeneous subregions seen on delayed contrast material-enhanced MR images and pale unstained necrotic subregions seen on histochemically stained specimens (8)(9)(10)(11). In several studies, researchers found heterogeneous microinfarcts in patients ( 2,5,12,13 ) and animals (8-11) on delayed contrastenhanced MR images.…”

Effect of metoprolol on myocardial apoptosis after coronary microembolization in rats

“…[2] Furthermore, CME can also lead to progressive myocardial malfunction, including overt myocardial infarction, contractile dysfunction, arrhythmias and coronary reserve reduction. [4,5] Once CME occurs, clinical outcomes of such patients are not improved by using coronary thrombolysis agents, nitroglycerin and platelet GPIIb/IIIa receptor antagonists or direct thrombectomy. [6,7] Therefore, therapy for CME remains an issue and furthermore, the underlying molecular mechanisms of pathophysiology in CME remain to be elucidated.…”

Novel motor design for rotating anode x-ray tubes operating in the fringe field of a magnetic resonance imaging system

“…XMR suites typically have become more available, with various vendors offering dual-modality solutions. [1][2][3][4][5][6][7][8][9][10][11][12][13] These systems combine the three-dimensional imaging capabilities and excellent soft tissue contrast provided by MR with the high spatial/temporal resolution and accurate device tracking provided by x ray. To eliminate system compatibility concerns, the suites typically have long travel distances between MR and x-ray components.…”