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Noninvasive Quantification of Blood Flow in Epicardial Coronary Arteries, Coronary Artery Bypass Grafts, and Anastomoses

Ferguson, T. Bruce Jr MD; Chen, Cheng PhD; Kim, Sunghan PhD; Jacobs, Kenneth PhD; Peng, Zhiyong PhD; Zhu, Zhen PhD; Buch, Ashesh N. MD; Basham, Jeffery C. MBA

Innovations: Technology & Techniques in Cardiothoracic & Vascular Surgery: January/February 2017 - Volume 12 - Issue 1 - p 50–59
doi: 10.1097/IMI.0000000000000345
Original Articles

Objective: Direct flow measurement in native epicardial coronary arteries, bypass conduits, and anastomoses is severely limited by the invasiveness and inaccuracy of existing technologies. As a result, less than 25% of patients undergoing coronary artery bypass grafting (CABG) worldwide have any intraoperative evaluation performed. A simple, accurate, and noninvasive technology to directly quantify blood flow and rheology surrounding anastomotic sites is a critical unmet need in CABG.

Methods: Existing technology limitations drove development of a different technology solution. With an optical physics approach, flow in conduits and tissue can be quantified in real time with nonionizing broad-spectrum imaging as well as temporal and spatial analyses. Cardiac motion, calibration, and combining anatomy + physiology in imaging were challenges requiring solutions.

Results: This patented imaging technology was developed and tested in an established porcine cardiac experimental model and in clinical proof-of-concept studies. Flow velocities and flows in epicardial coronary arteries vary physiologically with the cardiac cycle and with acute ischemia, as predicted by previous studies using traditional technologies. Imaging data are captured from a 30-cm viewing distance, analyzed and displayed in real time as a video. The field of view enables capture of flow in the proximal and distal epicardial coronary, the conduit, at the anastomosis and in the distal myocardium simultaneously.

Conclusions: Rheologic flow interaction between conduit and native coronary at the anastomosis remains the most poorly understood technical aspect of CABG. A noninvasive, noncontact, no-risk imaging technology as simple as a snapshot can provide this critical physiologic information, validate and document intraoperative quality, and improve even further CABG outcomes.

From the *Department of CV Sciences, East Carolina Heart Institute, Greenville, NC USA; †East Carolina Diabetes and Obesity Institute, Greenville, NC USA; Departments of ‡Bioengineering and §Physics, East Carolina University, Greenville, NC USA; ∥Department of CV Sciences-Interventional Cardiology, East Carolina Heart Institute, Greenville, NC USA; and ¶RFPi, LLC, Greenville, NC USA.

Accepted for publication December 18, 2016.

A video clip is available for this article. Direct URL citations appear in the printed text and are provided in the HTML and PDF versions of this article on the journal’s Web site (www.innovjournal.com).

Presented at the Annual Scientific Meeting of the International Society for Minimally Invasive Cardiothoracic Surgery, June 15–18, 2016, Montreal, Quebec, Canada.

Supported in part by a grant from the GoldenLEAF Foundation of North Carolina (T. Bruce Ferguson, Jr, MD), and by RFPi, LLC. Cheng Chen, PhD, is fully supported and Sunghan Kim, PhD, and Zhen Zhu, PhD, are partially supported by a sponsored research agreement with East Carolina University, funded by RFPi, LLC. Zhiyong Peng, PhD, is supported by a grant from the NC Golden LEAF Foundation.

Disclosures: T. Bruce Ferguson, Jr, MD, and Cheng Chen, PhD, are co-inventors of this described platform technology, which is owned by East Carolina University and licensed to RFPi, LLC, Greenville, NC USA. Ferguson and Chen are also founders of RFPi, LLC. Sunghan Kim, PhD, Kenneth Jacobs, PhD, and Zhiyong Peng, PhD, are inventors on patent applications involving this technology. Ashesh N. Buch, MD, is a consultant with equity to RFPi, LLC, and Jeffery C. Basham, MBA, is the CEO of RFPi, LLC. Zhen Zhu, PhD, declare no conflicts of interest.

Address correspondence and reprint requests to T. Bruce Ferguson, Jr, MD, Department of CV Sciences, East Carolina Heart Institute, Brody School of Medicine at East Carolina University, 115 Heart Dr, Greenville, NC 27834 USA. E-mail: fergusont@ecu.edu.

©2017 by the International Society for Minimally Invasive Cardiothoracic Surgery