Computational optimization of a novel atraumatic catheter for local drug delivery in coronary atherosclerotic plaques

Early identification and treatment of high-risk plaques before they rupture, and precipitate adverse events constitute a major challenge in cardiology today. Computational simulations are a time- and cost-effective way to study the performance, and to optimize a system. The main objective of this work is to optimize the flow of a novel atraumatic local drug delivery catheter for the treatment of coronary atherosclerosis. The mixing and spreading effectiveness of a drug fluid was analyzed utilizing computational fluid dynamics (CFD) in a coronary artery model. The optimum infusion flow of the nanoparticle-carrying drug fluid was found by maximizing the drug volume fraction and minimizing drug velocity at the artery wall, while maintaining acceptable wall shear stress (WSS). Drug velocities between 15 m/s and 20 m/s are optimum for local drug delivery. The resulting parameters from this study will be used to fabricate customized prototypes for future in-vivo experiments.

In Vivo Near-Infrared Fluorescence Imaging of Atherosclerosis Using Local Delivery of Novel Targeted Molecular Probes

This study aimed to evaluate the feasibility and accuracy of a technique for atherosclerosis imaging using local delivery of relatively small quantities (0.04-0.4 mg/kg) of labeled-specific imaging tracers targeting ICAM-1 and unpolymerized type I collagen or negative controls in 13 rabbits with atheroma induced by balloon injury in the abdominal aorta and a 12-week high-cholesterol diet. Immediately after local infusion, in vivo intravascular ultrasonography (IVUS)-NIRF imaging was performed at different time-points over a 40-minute period. The in vivo peak NIRF signal was significantly higher in the molecular tracer-injected rabbits than in the control-injected animals (P < 0.05). Ex vivo peak NIRF signal was significantly higher in the ICAM-1 probe-injected rabbits than in controls (P = 0.04), but not in the collagen probe-injected group (P = 0.29). NIRF signal discrimination following dual-probe delivery was also shown to be feasible in a single animal and thus offers the possibility of combining several distinct biological imaging agents in future studies. This innovative imaging strategy using in vivo local delivery of low concentrations of labeled molecular tracers followed by IVUS-NIRF catheter-based imaging holds potential for detection of vulnerable human coronary artery plaques.

Randomized trial of standard versus ClearWay-infused abciximab and thrombectomy in myocardial infarction: rationale and design of the COCTAIL II study

BACKGROUND

Patients with ST-elevation myocardial infarction (STEMI) are at substantial risk of suboptimal procedural results and late adverse events. Angiography and optical coherence tomography (OCT) studies have identified residual coronary thrombus and microcirculatory injury as potential culprits for these adverse outcomes. We hypothesized that coronary thrombectomy and local infusion of glycoprotein IIb/IIIa inhibitors by means of a dedicated infusion device can synergistically improve results of percutaneous coronary intervention (PCI) for STEMI, as appraised by OCT.

METHODS

A total of 128 patients with STEMI will be randomized, to one of the following: abciximab infusion with the ClearWay coronary catheter (C), standard abciximab infusion (A), thrombectomy followed by abciximab infusion with the ClearWay catheter (T+C), or thrombectomy followed by standard abciximab infusion (T+A). The primary objective is to demonstrate that abciximab infusion with the ClearWay catheter with or without manual thrombus aspiration (groups C or T+C) will result in a significant reduction of intrastent thrombus formations when compared with intravenous or intracoronary abciximab with or without thrombectomy (groups A or T+A). The primary endpoint will be the number of cross-sections with thrombus area more than 10% immediately after stent implantation as assessed with OCT. Additional angiographic, ECG and clinical endpoints will be collected and adjudicated.

CONCLUSION

This trial will provide important mechanistic insights on the most appropriate invasive treatment strategy for patients with STEMI and significant thrombus burden, by exploiting its factorial design and reliance on sensitive OCT endpoints.

Rationale and design of the INFUSE-AMI study: A 2 × 2 factorial, randomized, multicenter, single-blind evaluation of intracoronary abciximab infusion and aspiration thrombectomy in patients undergoing percutaneous coronary intervention for anterior ST-segment elevation myocardial infarction

BACKGROUND

Whether thrombus aspiration and local glycoprotein IIb/IIIa administration reduce infarct size in patients with ST-elevation myocardial infarction (STEMI) undergoing primary percutaneous coronary intervention (PCI) has not been established in multicenter studies.

DESIGN

INFUSE-AMI is a multicenter, open-label, controlled, single-blind randomized study enrolling 452 subjects with anterior STEMI and an occluded proximal or mid-left anterior descending artery with thrombosis in myocardial infarction 0, 1, or 2 grade flow undergoing primary PCI with bivalirudin anticoagulation. Subjects are randomized in a 2 × 2 factorial to one of the following 4 arms: (1) local infusion of abciximab using the ClearWay RX Local Therapeutic Infusion Catheter (ClearWay, Atrium Medical Corp, Hudson, NH) after aspiration with a 6F Export Aspiration Catheter (Medtronic, Inc, Minneapolis, MN), (2) local infusion of abciximab using the ClearWay RX Infusion Catheter and no aspiration, (3) no local infusion of abciximab and aspiration with a 6F Export Aspiration Catheter, or (4) no local infusion of abciximab and no aspiration. The primary end point is infarct size (percentage of total left ventricular mass) at 30 days measured by cardiac magnetic resonance imaging. Other secondary end points include microvascular obstruction by cardiac magnetic resonance imaging at 5 days, ST-segment resolution, angiographic myocardial perfusion, thrombus burden, angiographic complications, and clinical events through 1-year follow-up. Safety end points include major and minor bleeding.

SUMMARY

INFUSE-AMI is testing the hypothesis that the intracoronary administration of an abciximab bolus with or without thrombus aspiration before stent implantation compared to no infusion with or without thrombus aspiration reduces infarct size among patients undergoing primary PCI for anterior STEMI who are treated with bivalirudin.