DES: Friend or Foe?
Other morphologic changes that predispose stent thrombosis are malapposition (n=8), stenting of bifurcation lesions (n=7), AMI patients (n=8), and overlapping stents (n=4). All showed delayed healing, which is further exaggerated either from turbulent flow at malapposition or bifurcation sites or poor healing at sites of plaque rupture, and overlapping stents. Excessive length (>30 mm) is a correlate of LST as well as presence of uncovered stent struts. Uniformly all cases with thrombi have presence of fibrin, poor stent coverage by neointima, and less endothelialization.
All 78 lesions that were patent (and DES was not the cause of death) and had been in place for >30 days showed less neointima as compared to bare metal stents (BMS) thus suggesting that DES are effective in reducing neointimal thickness. A parameter, which is uniformly observed in BMS is that the neointimal formation (smooth muscle cells in matrix) around the circumference of the stent tends to be uniform in distribution. In DES there is heterogeneity of healing with areas showing excessive fibrin and others with smooth muscle cells within matrix and uneven luminal endothelialization.
Cypher and Taxus stents although use different drug and coatings, both reduce neointimal formation from delayed healing. However, there are inherent differences in the response to each of the stents in man with fibrin deposition being more frequent in Taxus stent while inflammation especially eosinophilic infiltrate and giant cell reaction being greater in the Cypher stent.
One can conclude from these histologic studies that because of underlying atherosclerotic plaque morphology differences, variability in healing from patient to patient, and a hypersensitivity in some patients; DES technology may have to be tailored to individual patient characteristics, rather than one stent fits all.
Notes to editors:
This presentation was made at the ESC Congress 2007 in Vienna.
The European Society of Cardiology (ESC):
The ESC represents nearly 53,000 cardiology professionals across Europe and the Mediterranean. Its mission is to reduce the burden of cardiovascular disease in Europe.
The ESC achieves this through a variety of scientific and educational activities including the coordination of: clinical practice guidelines, education courses and initiatives, pan-European surveys on specific disease areas and the ESC Annual Congress, the largest medical meeting in Europe. The ESC also works closely with the European Commission and WHO to improve health policy in the EU.
The ESC comprises 3 Councils, 5 Associations, 19 Working Groups, 50 National Cardiac Societies and an ESC Fellowship Community (Fellow, FESC; Nurse Fellow, NFESC). For more information on ESC Initiatives, Congresses and Constituent Bodies see www.escardio.org.
European Society of Cardiology, The European Heart House 2035 Route des Colles, B.P. 179 - Les Templiers, Sophia Antipolis F-06903 France
About the Author(s)
Renu Virmani, MD
CVPath Institute, Gathersburg, Maryland, US
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