What Should We Do About Lipid Core Plaque? The InfraReDx LipiScan IVUS and the CANARY Trial

CLD did not speak to Dr. Rizik in time to include his comments with those of the other CANARY trial investigators in the November 2010 article. Below, Dr. Rizik shares his experience with the LipiScan and thoughts on the CANARY trial. We have been using the LipiScan for a little over a year now and have found it ridiculously easy to use. The images are very easy to interpret and what I call the “knobology” of the device is easy to learn. The LipiScan IVUS is no more complex than placing a standard intravascular ultrasound (IVUS) device. It has not posed any issues with the learning curve and takes about the same exact timeframe as using an IVUS catheter. With its assessment of the vessel, NIR spectroscopy provides a treasure trove of information that we weren’t capable of obtaining prior to this technology. We now have the ability to assess the coronary artery for not only the degree of stenosis, but also the lipid burden in the vessel. Understanding the lipid burden in the coronary artery may help us to recognize which patients are vulnerable to worsening coronary disease. For example, we believe that patients with a high lipid burden, as seen with the LipiScan, may be at somewhat higher risk for going on to develop a myocardial infarction. We have seen several cases in which the LipiScan may have provided us information on which treated lesions may be vulnerable to stent thrombosis and restenosis after a stent has been placed. I would caution, this is very preliminary information. Although we are still in the infancy stages in terms of our understanding of this technology, we do use the LipiScan to modify our strategy in the cath lab. If we find a high lipid core burden index in patients where a stent will be placed, we may take steps to try and prevent some of that lipid core from going downstream. We tend not to leave a stent on the edge of a lipid core plaque. There is very little clinical and financial cost to extending the stent by several millimeters. At this point, we are fairly comfortable extending the stent so the edge is not sitting in the middle of a lipid core plaque. Distal embolization in the vessel is associated with post procedural myocardial infarctions. A number of clinical observations have suggested that patients with a high lipid core burden index, as measured by the LipiScan, may be at risk for distal embolization in the vessel. The CANARY trial is designed to test the hypothesis that patients with a high lipid core burden may benefit from embolic protection at the time of angioplasty and stenting. Patients with a high lipid core burden index will be randomized to embolic protection or standard of care. The CANARY trial will determine if there is a difference between those patients who had distal protection versus those who did not have distal protection. Dr. Rizik can be contacted at davidrizik@aol.com Disclosure: Dr. Rizik reports no conflict of interest regarding the content herein.