Oral Presentations - Pathology and Laboratory Medicine - University ...

OtherCrystal Leung, Amrit Samra, Lise Matzke, Mike AllardJames Hogg Research Centre, Providence Heart + Lung Institute, St. Paul’s Hospitaland Department of Pathology and Laboratory Medicine, University of British Columbia,Vancouver, BC, CanadaAbstract # 26methodological issues related to pathologicalevaluation of coronary artery stentsCrystal LeungBackround/ObjectivesIntravascular placement of metallic stents is currently a common means of treatment for stenosed coronary arteries.Coronary stents are, however, associated with risk of in-stent restenosis and late-stent thrombosis which may lead torepeated target vessel revascularization or other life threatening conditions such as myocardial infarction or death.Pathological evaluation of stented coronary arteries is needed to document these complications and to characterizestent-tissue interactions in order to improve safety and efficacy of coronary stents. Thus, high quality tissue sections arerequired with excellent preservation of the morphology of stented artery, particularly at the stent-tissue interface.MethodsThirteen stented coronary artery segments from six cases of cardiac transplantation and seven routine autopsies,fixed in 10% neutral buffered formalin, were used. These specimens were dehydrated in an increasing graded seriesof isopropanol. In a vacuum chamber, the specimens were immersed in infiltration solution (benzoylperoxide withhydroxyethyl methacrylate) from the JB-4 Plus Embedding Kit® (Polysciences, Inc.). The specimens were thentransferred into the embedding medium (infiltration solution with polyethylene glycol) and let polymerized underanaerobic conditions. After the medium has hardened, the specimens were cut into 5mm thick plastic blocks witha high-speed rotary saw. The plastic blocks were then affixed to the specimen holder using the embedding mediumand sectioned with a JB-4 microtome (Sorvall®). The sections were subjected to hematoxylin and eosin staining andphotomicroscopy was performed using the Nikon® CoolScope Digital Microscope.ResultsAfter successful processing, embedding, and staining, morphology of all 13 coronary artery segments, including thestent-tissue interface, was preserved and readily visible. To achieve adequate staining intensity, the sections of thestented arteries required prolonged hematoxylin staining. Some stents were displaced from their original implantedposition during sectioning and staining. Attempts to use another plastic embedding medium (Technovit 9100 methylmethacrylate) have been unsuccessful so far. This is primarily related to failure of the block to adhere to the holderduring sectioning.ConclusionsUsing the glycol methacrylate embedding technique, the morphology of the stent-tissue interface of stented arteriescan be readily observed by microscopy. Failure to maintain the stent in its original position is an importantlimitation, possibly related to the relative softness of the medium. Refining the methodology may lead to a moreefficient protocol and enable more specialized staining and immunohistochemistry as well as the use of harder plasticmedia such as methyl methcrylate.Poster Presentations * 2 0 1 037