Detection of Acutely Impaired Microvascular Reperfusion After Infarct Angioplasty With Magnetic Resonance Imaging

Abstract

Background-Despite the reopening of the infarct-related artery (IRA) with infarct angioplasty, complete microvascular reperfusion does not always ensue. Methods and Results-We performed cardiovascular MRI (CMR) in 20 acute myocardial infarction (AMI) patients within 24 hours of successful infarct angioplasty and 10 control patients without obstructive coronary artery disease on a clinical 1.5-T CMR scanner. Three-month follow-up CMR in AMI patients evaluated the impact of abnormal reperfusion on recovery of function. Infarction was localized by delayed contrast hyperenhancement and impaired systolic thickening. Microvascular perfusion was assessed at rest by first-pass perfusion CMR after a bolus of gadolinium-DTPA by use of the time to 50% maximum myocardial enhancement. Whereas contrast wash-in was homogeneous in control patients, AMI patients exhibited delays in the hypokinetic region subtended by the IRA compared with remote segments in 19 of 20 patients, with a mean contrast delay of 0.9Ϯ0.1 seconds (95% CI, 0.6 to 1.2 seconds). At follow-up, the mean recovery of systolic thickening was lower in segments with a contrast delay of 2 seconds or more (10Ϯ7% versus 39Ϯ4%, PϽ0.001). A contrast delay Ն2 seconds and infarction Ͼ75% transmurally were independent predictors of impaired left ventricular systolic thickening at 3 months (Pϭ0.002 for severe contrast delay, Pϭ0.048 for Ͼ75% for transmural infarction). Conclusions-CMR detects impaired microvascular reperfusion in AMI patients despite successful infarct angioplasty, which when severe is associated with a lack of recovery of wall motion.

Diffuse Ventricular Fibrosis Is a Late Outcome of Tachycardia-Mediated Cardiomyopathy After Successful Ablation

“…Initial cine CMR sequences were performed in 3 standard long-axis (4-, 3-, and 2-chamber views) and short-axis slices (basal, mid, and apical), kept identical for each subsequent sequence throughout the CMR examination. 16 From an end-diastolic, 4-chamber, long-axis view, 5 equally spaced short-axis slices were planned, so that the 2 outer slices lined up exactly either with the tip of the apex or the mitral annulus. The 2 outer slices were then deleted, leaving 3 slices corresponding to typical basal, mid, and apical short-axis views.…”

Magnetic Resonance Imaging in Myocardial Fibrosis Related to Ischemic Events

“…Kim et al questioned whether there is a correlation between delayed contrast enhancement and the age of myocardial infarction, as well as the use of CMR to detect viability and irreversible lesions and evaluate the contractile function of the myocardium. [21][22][23][24] The theory was tested on canine models, and their results revealed that in the first 24 hours from the infarction, hyperenhancement occurs both in the necrosis zone and at the borderline that includes the hibernating myocardium. In terms of chronic infarction, the contrast agent has a strict affinity for the fibrosis area, and the imaging delineation of the hibernated myocardium from the necrosis area is a real challenge.…”

Detection of apoptosis in patients with coronary artery disease : Assessment of temporal patterns and potential sources

“…It may manifest at the time of PCI as persistent STelevation and coronary 'no-reflow' i.e TIMI flow ≤2 as defined by the Thrombolysis in Myocardial Infarction (TIMI) blood flow grade scale, used to evaluate the quality of coronary flow during coronary angiography [111,112]. The presence of the no-reflow phenomenon indicates a microvascular obstruction and its presence in reperfused STEMI patients, as visualised eg by cardiac magnetic resonance imaging (CMR), is associated with larger infarct size, worse LV ejection fraction, adverse LV remodelling as well as unfavorable short and long term outcomes [113][114][115][116].…”