Author + information
- Received January 13, 1992
- Revision received July 6, 1992
- Accepted July 14, 1992
- Published online January 1, 1993.
- Heleen M.M. van Beusekom, MSca,
- Willem J. van der Giessen, MDa,
- Robert J. van Suylen, MD∗,
- Egbert Bos, MD†,
- FréT. Bosman, MD∗ and
- Patrick W. Serruys, MD, FACC∗,a
- ↵∗Address for correspondence: Patrick W. Semiys, MD, Department of Cardiology, Thoraxcenter, Ee 2332, Erasmus University Rotterdam, PO Box 1738 3000 DR Rottendam The Netherlands.
Objectives. To gain insight into the mechanism of stenting in humans and its short- and long-term implications, we studied the vascular wall of saphenous vein aortocoronary bypass grafts after implantation of the Wallstent.
Background. The implantation of a stent in aortocoronary bypass grafts may provide an alternative solution for revascularization in patients who are poor candidates for reoperation. Because human histopathologic findings after stenling with the Wallstent have not previously been described in detail, we examined graft segments that were surgically retrieved from 10 patients (21 stents) at 3 days to 10 months after implantation of the stent.
Methods. The grafts were examined by a combination of the following techniques: light microscopy, immunocytochemistry and both scanning and transmission electron microscopy.
Results. Early observations revealed that large amounts of platelets and leukocytes adhered to the stent wires during the first few days. At 3 months, the wires were embedded in a layered new intimai thickening, consisting of smooth muscle cells in a collagenous matrix. In addition, foam cells were abundant near the wires. Extracellular lipids and cholesterol crystals were found after 6 months. Smooth muscle cells and extracellular matrix formed the predominant composent of restemisis. This new intimal thickening was lined with eadotitelium, in some cases showing defect intercellular junctions and abnorma; adherence of leukocytes and platelets as late as 10 months after implantation.
Conclusions. This type of steal is potentially thrombogenic and seems to be associated with extracellular lipid accumulation in venous aortocoronary bypass grafts.
☆ This study was presented in part at the 40th Annual Scientific Session of the American College of Cardiology, Atlanta, Georgia. March 1991. It was supported by Grants NHS 88-077 from the Netherlands Heart Foundation and 87159 from the Dutch Ministry of Science and Education.
- Received January 13, 1992.
- Revision received July 6, 1992.
- Accepted July 14, 1992.