Velocity Vector Imaging, a new feature-tracking method, can accurately assess regional myocardial function at the endocardial level and is a promising clinical tool for the simultaneous quantification of regional and global myocardial function.

Objective-To determine the accuracy of detection of different tissue types of intravascular ultrasound-virtual histology (IVUS-VH) in a porcine model of complex coronary lesions. Methods and Results-Coronary lesions were induced by injecting liposomes containing human oxidized low-density lipoprotein into the adventitia of the arteries. IVUS-VH imaging was performed in vivo at 8.2Ϯ1.6 weeks after injection. A total of 60 vascular lesions were analyzed and compared with their correspondent IVUS-VH images. Correlation analysis was performed using linear regression models. Key Words: animal model Ⅲ intravascular ultrasound Ⅲ vulnerable plaque C omplex atherosclerotic plaques containing specific morphological features appear to be responsible for the majority of major coronary events. 1-4 Therefore, the accurate identification and characterization of these lesions has become one of the major challenges of interventional cardiology. 5 Several catheter-based imaging devices designed and built to characterize such features are currently undergoing development. 6 -10 Mainly because of the lack of a large animal model of atherosclerotic vascular disease, the initial development of these technologies is based on the construction of mathematical algorithms based on data acquired from ex vivo evaluation of postmortem human arterial specimens. Therefore, the translation of these algorithms of detection into an in vivo setting may not be universally accurate.Virtual histology is an intravenous ultrasound (IVUS)-based technology that studies the spectral analysis of the radio frequency signals backscattered from the plaque during IVUS imaging and reconstructs the morphology of the plaque through color-coded maps. 11 Although this technique has been validated in vitro and ex vivo in human coronary arteries [11][12][13][14] and preliminary clinical experience has been published, 15,16 little data have been published on histological correlates of images acquired in vivo. 17 In the present study, we describe the histological characteristics of complex coronary lesions analyzed in vivo using intravascular ultrasoundvirtual histology (IVUS-VH) in a porcine model of disease.

BACKGROUNDNumerous studies investigated cell-based therapies for myocardial infarction (MI). The conflicting results of these studies have established the need for developing innovative approaches for applying cell-based therapy for MI. Experimental studies on animal models demonstrated the potential of fresh, uncultured, unmodified, autologous adipose-derived regenerative cells (UA-ADRCs) for treating acute MI. In contrast, studies on the treatment of chronic MI (CMI; > 4 wk post-MI) with UA-ADRCs have not been published so far. Among several methods for delivering cells to the myocardium, retrograde delivery into a temporarily blocked coronary vein has recently been demonstrated as an effective option.AIMTo test the hypothesis that in experimentally-induced chronic myocardial infarction (CMI; > 4 wk post-MI) in pigs, retrograde delivery of fresh, uncultured, unmodified, autologous adipose-derived regenerative cells (UA-ADRCs) into a temporarily blocked coronary vein improves cardiac function and structure.METHODSThe left anterior descending (LAD) coronary artery of pigs was blocked for 180 min at time point T0. Then, either 18 × 106 UA-ADRCs prepared at “point of care” or saline as control were retrogradely delivered via an over-the-wire balloon catheter placed in the temporarily blocked LAD vein 4 wk after T0 (T1). Effects of cells or saline were assessed by cardiac magnetic resonance (CMR) imaging, late gadolinium enhancement CMR imaging, and post mortem histologic analysis 10 wk after T0 (T2).RESULTSUnlike the delivery of saline, delivery of UA-ADRCs demonstrated statistically significant improvements in cardiac function and structure at T2 compared to T1 (all values given as mean ± SE): Increased mean LVEF (UA-ADRCs group: 34.3% ± 2.9% at T1 vs 40.4 ± 2.6% at T2, P = 0.037; saline group: 37.8% ± 2.6% at T1 vs 36.2% ± 2.4% at T2, P > 0.999), increased mean cardiac output (UA-ADRCs group: 2.7 ± 0.2 L/min at T1 vs 3.8 ± 0.2 L/min at T2, P = 0.002; saline group: 3.4 ± 0.3 L/min at T1 vs 3.6 ± 0.3 L/min at T2, P = 0.798), increased mean mass of the left ventricle (UA-ADRCs group: 55.3 ± 5.0 g at T1 vs 71.3 ± 4.5 g at T2, P < 0.001; saline group: 63.2 ± 3.4 g at T1 vs 68.4 ± 4.0 g at T2, P = 0.321) and reduced mean relative amount of scar volume of the left ventricular wall (UA-ADRCs group: 20.9% ± 2.3% at T1 vs 16.6% ± 1.2% at T2, P = 0.042; saline group: 17.6% ± 1.4% at T1 vs 22.7% ± 1.8% at T2, P = 0.022).CONCLUSIONRetrograde cell delivery of UA-ADRCs in a porcine model for the study of CMI significantly improved myocardial function, increased myocardial mass and reduced the formation of scar tissue.

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