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Functional lesion assessment in stable coronary disease is considered the gold standard. The result of fractional flow reserve (FFR) in stable coronary disease is often a decision-maker for patient qualification. Taking into account the paramount position of FFR, it is crucial to acknowledge and reduce all potential bias.In the present study, we quantified the influence of elevated HR on FFR results using a preclinical model and then validated the results in a clinical setting.The relationship between FFR and HR was first explored experimentally in a porcine model. A clinical validation study was conducted in patients with isolated moderate lesions in the left anterior descending artery (LAD) or right coronary artery (RCA). In both the experimental and clinical arms, FFR was measured at resting HR and with pacing at 100, 130, 160, and 180 (for pigs) beats per minute. In the porcine model and in the clinical settings, a significant correlation between FFR and HR was confirmed in the LAD (r = 0.89, p .0001; r = 0.53, p = .00002), but not in the RCA (r = -0.19, p = .5; r = 0.14, p = .3). Post hoc analyses revealed that the FFR values in the LAD at 130/min and above tended to be significantly different from the baseline HR.The results of this study indicate that in an experimental setting, tachycardia might be responsible for an overestimation of FFR results in LAD lesions. more...

OBJECTIVES: Surgical ventricular reconstruction has been used to treat ischaemic cardiomyopathy with large akinetic or dyskinetic areas. However, application of this approach requires a sternotomy, cardiopulmonary bypass and a left ventriculotomy. This study assessed the feasibility and efficacy of minimally invasive, off-pump, epicardial catheter-based ventricular reconstruction (ECVR) in an anteroapical aneurysm ovine model. METHODS: Left ventricular (LV) anteroapical myocardial infarction was induced percutaneously by coil embolization of the left anterior descending coronary artery. Eight weeks after infarction, via mini left thoracotomy and without cardiopulmonary bypass, ECVR was performed in six sheep. The scar was excluded by placing anchor pairs on the LV epicardial anterior wall and the right ventricular side of the interventricular septum under fluoroscopic guidance. LV performance was evaluated before, immediately after device implantation and after 6 weeks by echocardiography. Terminal histopathology was performed. RESULTS: ECVR was completed expeditiously in all animals without complications. Parameters obtained 6 weeks after device implantation were compared with baseline (pre-device). End-systolic volume was decreased by 38% (25.6 ± 6.1 ml vs baseline 41.2 ± 7.2 ml, P= 0.02) with preservation of stroke volume. Ejection fraction was significantly increased by 13% (48.5 ± 7% vs baseline 35.8 ± 7%, P= 0.02). The circumferential strain in the anterior septum (−7.67 ± 5.12% vs baseline −0.96 ± 2.22%, P= 0.03) and anterior wall (−9.01 ± 3.51% vs baseline −4.15 ± 1.36%, P= 0.01) were significantly improved. The longitudinal strain in apex was reversed (−3.08 ± 1.53% vs baseline 3.09 ± 3.39%, P= 0.01). Histopathology showed full endocardial healing over the anchors with appreciable reduction of the chronic infarct in the LV. CONCLUSIONS: ECVR without cardiopulmonary bypass is a less invasive alternative to current standard therapies, reverses LV remodelling and improves cardiac performance in an ovine model of anteroapical aneurysm. more...

AIMS To demonstrate the feasibility and safety of percutaneous delivery of the novel inflow cannula of the CircuLite® SYNERGY® pocket Micro-pump via transseptal access in the swine model. METHODS AND RESULTS After transseptal puncture, the inflow cannula system was advanced into the left atrium (LA) via the right external jugular vein and anchored onto the atrial septum under fluoroscopic and intracardiac echo guidance in 14 acute animals. Subsequently, chronic studies were performed to examine the long-term healing response to the cannula implantation with an artery-LA shunt (n=10) and overall safety of the Micro-pump components (n=6). Acute studies proved the concept of transcatheter delivery of the inflow cannula via superior venous access. The cannula tips were securely anchored in all chronic animals and appropriately endothelialised as early as two weeks. No thrombi or septal damage was observed. For the chronic pump group, device speed of 22,000 rpm (~2.0 L/min) was maintained without any adverse cardiac events. Plasma free haemoglobin assays confirmed the absence of clinically significant haemolysis. CONCLUSIONS The transcatheter delivery of the inflow cannula via superior venous access to the LA is feasible and safe. This percutaneous delivery presents a significantly less invasive alternative to deliver partial circulatory support devices. more...

ObjectivesThe authors aimed to validate a novel iliofemoral in-stent restenosis (ISR) model for the efficacy evaluation of paclitaxel-coated balloons (PCB) using the familial hypercholesterolemic swine (FHS).BackgroundMost of the validation work regarding PCB technologies has been performed in the coronary territory of juvenile domestic swine. Although invaluable for safety evaluation, this model is not suited for the evaluation of the efficacy of peripheral PCB technologies.MethodsTwenty-four iliofemoral segments in 12 FHS underwent balloon injury and self-expanding stent placement. After 21 days, the resulting ISR lesions were treated with either 1 μg/mm2 dose (n = 8), or 3 μg/mm2 dose (n = 8) PCB (Cotavance, Bayer Pharma AG/MEDRAD, Indianola, Pennsylvania), or with an identical uncoated control balloon (n = 8).ResultsAt termination (28 days after treatment), the percent diameter stenosis by quantitative vascular analysis in the control group was higher (31.2 ± 13.7%) compared with the 1 μg/mm2 (19.3 ± 14.0%, 38% reduction) and 3 μg/mm2 (8.6 ± 10.7%, 72% reduction) PCB groups. Intravascular ultrasound analysis showed 36% (1 μg/mm2 dose, p = 0.04) and 55% (3 μg/mm2 dose, p < 0.01) reductions in neointimal volume stenosis. In the histological analysis, the control group showed the highest degree of percent area stenosis (65 ± 14.3%). The reductions in percent area stenosis was 13.2% (p = 0.5) and 26% (p = 0.04) in the 1 μg/mm2 and 3 μg/mm2 dose groups, respectively.ConclusionsThe FHS model of iliofemoral ISR demonstrated a dose-dependent effect on the inhibition of neointimal proliferation of a clinically validated PCB technology. This model represents a positive step toward the efficacy evaluation of PCB in the peripheral vascular territory. more...

Background Clinical trials have consistently demonstrated benefits of Paclitaxel-coated balloons (PCB) in particular clinical situations such as in-stent restenosis and peripheral vascular interventions. However, the long-term vascular effects of bare metal stents (BMS) delivered via PCB (PCB+BMS) are still unknown. The aim of this study was to assess the long-term effects of PCB+BMS on vascular healing and neointimal formation (NF). Methods A total of 208 stents: 56 BMS crimped on PCB, 50 BMS crimped on uncoated balloons (UCB+BMS), 52 Taxus and 50 Cypher stents were implanted in normal coronary arteries of 104 pigs using 1.2:1.0 stent-to-artery ratio. Follow-up occurred at 3, 7, 28, 90, and 180 days. Vascular effects were assessed based on angiographic and histological analysis. Endothelialization was evaluated using an anti von-Willebrand Factor stain. Results At 28 days, delivery of a BMS using a PCB led to a significant reduction in NF compared to the UCB+BMS and the Taxus stent (P < 0.01). Between 28 and 180 days, the progression of NF tended to be lower in the PCB+BMS compared to all DES groups. At 90 days, the PCB+BMS (2.56 ± 0.43) and the Taxus stents (2.60 ± 0.59) had a trend toward higher inflammatory scores compared to the UCB+BMS group (1.85 ± 1.13, P = 0.09). By 180 days, inflammation and NF had completely normalized between the groups. Expression of peristrut vWF was comparable among all tested groups at 28 days. Conclusion The long-term pattern of vascular healing occurring following PCB+BMS deployment appears to be comparable to what has been reported with DES technologies. © 2012 Wiley Periodicals, Inc. more...

Background— Drug-coated balloons are rapidly emerging as a therapeutic alternative for the interventional treatment of peripheral vascular disease. The purpose of this study was to test the hypothesis that an angioplasty balloon coated with the mTOR inhibitor zotarolimus (ZCB) would inhibit neointimal hyperplasia in a novel injury-based superficial femoral artery model in the familial hypercholesterolemic swine. Methods and Results— A total of 44 familial hypercholesterolemic swine were included (12 designated to study tissue pharmacokinetics and 32 to study safety and efficacy). Fogarty balloon denudation was performed in all superficial femoral artery segments, followed by balloon angioplasty. In the pharmacokinetic study, a total of 24 ZCBs (300 μg/cm 2 ) were used. Zotarolimus was detected in arterial tissue at 5 minutes (162 ng/mg of tissue), 24 hours (5.9 ng/mg of tissue), and 28 days (0.007 ng/mg of tissue) after ZCB inflation. In the safety and efficacy study, superficial femoral artery segments were randomized to either high-dose (600 μg/cm 2 , n=16), low-dose (300 μg/cm 2 , n=16), or paired uncoated balloons (high-dose ZCB control, n=16; low-dose ZCB control, n=16). At 28 days, the percentage of angiographic stenosis was similar among all tested groups. Histological analysis demonstrated a reduction in neointimal formation in both ZCB groups compared with controls (high-dose ZCB 44% reduction, P =0.007; low-dose ZCB 22% reduction, P =0.08). There was no evidence of delayed arterial healing or vascular toxicity in any of the ZCB groups. Conclusions— The single delivery of zotarolimus via coated balloon is feasible, and therapeutic levels are maintained up to 28 days. The ZCB technology appears to be effective in the reduction of neointimal proliferation in the superficial femoral artery of the familial hypercholesterolemic swine. more...

Aims: Despite recent abundance of data on drug-coated balloon technology, the biological effects of paclitaxel coated balloon (PCB) treatment followed by bare metal stent (BMS) implantation in peripheral arteries (simulating bail-out stenting, a common clinical scenario), have not been published. Methods and results: PCB technology containing a paclitaxel-iopromide coating and identical iopromide-coated controls (without paclitaxel) were used in 16 porcine ilio-femoral arteries. The biological effects of inflating one (PCBxl) or two sequential (PCBx2) paclitaxel coated balloons before BMS implantation were compared to the single application of a control balloon (CCBx1; contrast coated balloons). At 30 days PCBx2 displayed significantly reduced late lumen loss by angiography (58% reduction vs. CCBx1; p=0.04) and neointimal area by histomorphometry (35% reduction vs. CCBx1 and 30% vs. PCBx1; p-0.02). Similarly, percent area stenosis in the PCBx2 group was reduced by 45% as compared to CCBx1 and PCBx1 (p=0.04). At this time, all parameters of vessel wall healing (including injury score, inflammation, and endothelialisation) following drug coated balloon treatment were comparable to the control group. Conclusions: Paclitaxel delivery to porcine ilio-femorals using PCB followed by BMS implantation effectively decreased neointimal proliferation. More extensive and prolonged proliferative response of the vessel after stenting (necessitating higher drug dose) could potentially explain the undetectable effect of PEBx1 relative to CCBx1 in this pilot study. Histological analysis confirmed the safety and biocompatibility of PCB technology. more...

Introduction To date, most of all new developments in stent technologies are tested in normal animals. Although invaluable in the evaluation of device safety, the juvenile domestic swine (DS) do not follow the biological healing response occurring in humans following coronary stent implantation. By using a novel swine breed afflicted with familial hypercholesterolemia (FHS), we aimed to analyse the vascular response occurring following bare metal stent (BMS) implantation by comparing in vivo endovascular imaging and histological data. Methods A total of 26 swine were included in this study (12 FHS and 14 DS). Sixty eight BMS (FHS = 28 versus DS = 40) were implanted using a 10% overstretch ratio. Imaging evaluation (IVUS and OCT) was conducted in all animals at 30 (n = 14) or 90 (n = 12) days following stent implantation. After imaging, the stented coronary segments were harvested for histological evaluation. Results At 30 days, the degree of neointimal formation analysed by OCT (%AS = DS 21.9 ± 10% versus FHS 25.4 ± 12%; p = 0.18) and histology (DS 24.6 ± 10% versus FHS 23.58 ± 10%; p = 0.8) was similar between both animal groups. At 90 days, the degree of neointimal formation in the DS group decreased in all analysed variables (−40% in IVUS neointimal volume, −57% in OCT %AS, and −30% in %AS by histology) compared to the progression of neointimal formation observed in the FHS group (+29% in IVUS neointimal volume, +27% in OCT %AS and +43% in %AS by histology). Conclusion The pattern of neointimal formation following BMS implantation in the FHS follows a progressive course that does not occur in the DS. Therefore, by providing a progressive neointimal biological response to BMS implantation, the FHS could serve as an ideal efficacy model for the validation of drug eluting stent technologies. more...

Background— We aimed to demonstrate that, by separating endothelial progenitor cell capture from sirolimus delivery through the application of drug to the abluminal surface of the stent, the degree of endothelialization can be enhanced. Methods and Results— Stainless steel R Stents, with biodegradable SynBiosys polymer coating with sirolimus abluminally applied and surface modified with anti-CD34 antibody were prepared at 2 dosages (low-dose sirolimus [LD-Combo, 2.5 μg sirolimus/mm] and full-dose sirolimus [Combo, 5 μg sirolimus/mm). These Combo stents and the Cypher stent (10 μg sirolimus/mm) were deployed in 98 normal porcine arteries and harvested for pharmacokinetic analysis at 0.25, 1, 3, 7, 14, 28, and 35 days. The LD-Combo stents showed faster early release (50%total dose in 72 hours) than the Combo and Cypher. At 30 days, drug release was near complete with both Combo stents, whereas 20% of drug remained on the Cypher stents. To assess efficacy, a total of 50 stents (Xience V=8, Cypher=8, Genous bioengineered R stent=6, LD-Combo=14, and Combo=14) were implanted in 18 pigs for 14 and 28 days. Optical coherence tomography was performed, and stents were harvested for histology. At 28 days, there was less neointimal thickness with Combo (0.173±0.088 mm) compared with Cypher (0.358±0.225 mm), LD-Combo (0.316±0.228 mm), and Xience V (0.305±0.252 mm; P Conclusions— Both optical coherence tomography and histology demonstrate that anti-CD34 sirolimus-eluting stents promote endothelialization while reducing neointimal formation and inflammation. more...

Objectives This study aimed to evaluate the accuracy of optical coherence tomography (OCT) in analyzing the neointimal response to several drug-eluting stent (DES) types by comparing OCT images acquired in vivo with corresponding histological specimens using a nondiseased porcine injury model. Background Optical coherence tomography is emerging as a promising endovascular imaging tool for the evaluation of neointimal response after DES implantation. Methods A total of 84 stents were implanted—22 ML Vision (Abbott Vascular, Santa Clara, California), 22 Xience V (Abbott Vascular), 20 Endeavor (Medtronic, Minneapolis, Minnesota), and 20 Taxus Liberte (Boston Scientific, Natick, Massachusetts) stents—in normal porcine coronary arteries and were harvested at 28 (n = 42) and 90 (n = 42) days, with the different stent types equally distributed between the 2 follow-up periods. At termination, morphometric evaluation using OCT imaging was performed in all stented arteries. Histological morphometric analysis was performed and correlated with OCT. Results A total of 622 OCT–histology matched frames acquired from all stent designs were analyzed. The luminal (13.7%) and stent (6.1%) areas were consistently larger by OCT compared with histology. The mean neointimal thickness was very similar between techniques (∼3.27% variation). There was a high correlation between OCT and histology for the evaluation of neointimal area (R2 = 0.804), luminal area (R2 = 0.825), and neointimal thickness (R2 = 0.789). Correlation for total stent area was poor (R2 = 0.352). Although the proportion of individual struts determined to be uncovered by OCT and histology was similar, there was significant variation in the estimation of strut coverage between OCT and histology when the neointimal thickness was between 20 and 80 μm. This variation converged for neointimal thicknesses between 80 and 100 μm. Conclusions Subtle differences in neointimal formation induced by current DES can be reproducibly analyzed in vivo by OCT. However, OCT measurement of stent area seems to have less correlation with histology. more...

Introduction Although saphenous vein grafts are widely used conduits for coronary artery bypass graft surgery, their clinical value remains limited due to high failure rates. The aim of the study was to evaluate feasibility, safety, and biocompatibility of peritoneal derived vascular grafts (PDVG) formed on a silicone-coated, latex, Foley catheter in a stromal cell-derived factor (SDF-1)- enriched environment. Methods Foley catheters were implanted into the parietal wall of 8 sheep. After 21 days the peritoneal cavity was re-opened and the newly formed tissue fragments were harvested. The animals were randomly assigned into: ( 1 ) study group in which conduits were incubated in a solution containing SDF-1, ( 2 ) control group without SDF-1 incubation. Left carotid arteries were accessed and “end-to-side” anastomoses were performed. Biological materials for histological examination were taken at 4, 7, 10, and 14 days. Results and Conclusions The study proved safety, feasibility, and biocompatibility of PDVG formed on the basis of a silicone-coated, latex catheter in an SDF-1 chemokine-enriched environment. These biological grafts effectively integrated with the native high-pressure arterial environment in an ovine model and provided favorable vascular profile. The potential clinical value of this technology needs to be further elucidated in long-term preclinical and clinical studies. more...

Background: Self-expanding stents (SES) are reemerging as therapeutic alternatives to treat coronary artery disease. It has been proposed that SES can improve clinical outcomes by inducing less injury at implantation and achieving better vessel wall apposition.To date, little data exists comparing the vascular response to both methods of deployment in a controlled experimental setting. Objective: To quantify differences in vascular injury and healing between second-generation SES and balloon-expandable stents (BES) and the effects of balloon post-dilatation in a porcine coronary model. Methods: Seventy-five bare SES (AXXESS or vProtect) and 42 BES (Vision) were implanted in porcine coronaries. A subset of these received balloon post-dilatation(SES 1 D 5 22, BES 1 D 5 20). Follow-up was scheduled at 30 (BES 5 10, BES 1 D 56, SES 5 19, SES 1 D 5 8), 90 (BES 5 6, BES 1 D 5 8, SES 5 19, SES 1 D 5 8), and 180 days (BES 5 6, BES 1 D 5 6, SES 5 15, SES 1 D 5 6). Results: In vivo imaging and histological analysis showed that neointimal formation peaks early (30 days) in BES. Conversely, for SES, the peak occurred later (90 days). However, the neointimal formation achieved in either group equalized at 180 days. For SES, post-dilatation shortened the peak of neointimal formation to 30 days. Conversely, for BES, post-dilatation delayed the peak of neointimal formation to 90 days. At 30 days, histology showed that SES had significantly less injury. However, at 90 days, injury scores tended to be higher for SES. By 180 days, injury scores were comparable between both groups. Conclusions: The mechanism of stent expansion influences the degree of vascular injury and healing. The synergistic use of balloon post dilatation changes the dynamics of healing and may impact the potential beneficial effects inherent to SES technologies. more...

The administration of bone marrow-derived stem cells may provide a new treatment option for patients with heart failure. Transcatheter cell injection may require multi-imaging modalities to optimize delivery. This study sought to evaluate whether endomyocardial injection of mesenchymal precursor cells (MPCs) could be guided by real-time 3D echocardiography (RT3DE) in treating chronic, postinfarction (MI) left ventricular (LV) dysfunction in sheep. Four weeks after induction of an anterior wall myocardial infarction in 39 sheep, allogeneic MPCs in doses of either 25 × 106 ( n = 10), 75 × 106 ( n = 9), or 225 × 106 ( n = 10) cells or nonconditioned control media ( n = 10) were administered intramyocardially into infarct and border zone areas using a catheter designed for combined fluoroscopic and RT3DE-guided injections. LV function was assessed before and after injection. Infarct dimension and vascular density were evaluated histologically. RT3DE-guided injection procedures were safe. Compared to controls, the highest dose MPC treatment led to increments in ejection fraction (3±3% in 225M MPCs vs. −5±4% in the control group, p < 0.01) and wall thickening in both infarct (4±4% in 225M MPCs vs. −3±6% in the control group, p = 0.02) and border zones (4±6% in 225M MPCs vs. −8±9% in the control group, p = 0.01). Histology analysis demonstrated significantly higher arteriole density in the infarct and border zones in the highest dose MPC-treated animals compared to the lower dose or control groups. Endomyocardial implantation of MPCs under RT3DE guidance was safe and without observed logistical obstacles. Significant increases in LV performance (ejection fraction and wall thickening) and neovascularization resulted from this technique, and so this technique has important implications for treating patients with postischemic LV dysfunction. more...

Purpose To assess the effects of local paclitaxel delivery using the Remedy catheter on neointimal hyperplasia in a porcine model and compare these results to commercially available BMS and biodegradable polymer-coated paclitaxel-eluting stents (BP-PES). Methods and materials A total of 31 stents were implanted into coronary arteries of 15 domestic swine including eight BMS, six BP-PES, and 17 BMS after intravasal paclitaxel delivery at doses of 250 μg (LPD250; n =9) and 500 μg (LPD500, n =6). All stents were implanted under quantitative coronary angiography (QCA) guidance to achieve a balloon/artery diameter ratio of 1.15:1.0. Twenty-eight days after the procedure, follow-up coronary angiography was performed, the animals were euthanized, and the coronary arteries harvested for histopathological analysis. Results At follow-up, QCA analysis revealed that lumen loss was significantly worse in BMS and in both LPD groups in comparison to BP-PES stents ( P =.02). Histomorphometric analysis showed that the LPD500 group presented the highest percentage of area stenosis, achieving a statistically significant difference in comparison to BMS and BP-PES stents. Conclusion Our study demonstrates that local paclitaxel delivery using the Remedy transport catheter in the two studied doses (250 and 500 μg) is not effective at neointimal hyperplasia inhibition. more...

ObjectiveThe loss of normal apical rotation is associated with left ventricular (LV) remodeling and systolic dysfunction in patients with congestive heart failure after myocardial infarction. The objective of the present study was to evaluate the effect of epicardial ventricular reconstruction, an off-pump, less-invasive surgical reshaping technique, on myocardial strain, LV twist, and the potential alteration of myocardial fiber orientation in an ovine model of LV anteroapical aneurysm.MethodsLV anteroapical myocardial infarction was induced by coil embolization of the left anterior descending artery. Eight weeks after occlusion, epicardial ventricular reconstruction was performed using left thoracotomy under fluoroscopic guidance in 8 sheep to completely exclude the scar. The peak systolic longitudinal/circumferential strains and LV twist were evaluated using speckle tracking echocardiography before (baseline), after device implantation, and at 6 weeks of follow-up.ResultsEpicardial ventricular reconstruction was completed in all sheep without any complications. Immediately after device implantation, LV twist significantly increased (4.18 ± 1.40 vs baseline 1.97 ± 1.92; P = .02). The ejection fraction had increased 17% and LV end-systolic volume had decreased 40%. The global longitudinal strain increased from −5.3% to −9.1% (P more...