P325	Statin use and plaque phenotype: a retrospective study in 378 patients undergoing carotid endarterectomy.
1W.E.Hellings, 1B.A.N.Verhoeven, 1F.L.Moll, 2J.Koekkoek, 3J-P.P.M.de Vries, 2E.Velema, 4P.de Bruin, 2G.Pasterkamp
1Vascular surgery, UMC Utrecht, Utrecht, NL; 2Experimental cardiology, UMC Utrecht, Utrecht, NL; 3Vascular Surgery, St. Antonius Hospital, Nieuwegein, NL; 4Pathology, St. Antonius Hospital, Nieuwegein, NL.

Introduction Pleiotrophic effects of statins on atherosclerotic plaques are mainly defined as reduction of the lipid core and impaired influx or increased apoptosis of inflammatory cells in combination with less protease activity. These effects were observed in animal models and small sized human studies. We retrospectively evaluated the effect of statin treatment in a cohort of patients undergoing carotid endarterectomy. Methods We included 378 patients undergoing carotid endarterectomy (CEA). Blood was withdrawn at baseline for determination of CRP and lipid spectra. All patients filled in a questionnaire concerning cardiovascular risk factors. Immunohistochemical stainings for the presence of macrophages, smooth muscle cells, collagen and fat were performed on the culprit lesion. Protein was isolated to determine MMP activity. Results Serum CRP and cholesterol levels were significantly lower in 249 patients using statins (4.7 vs. 5.7 mg/l and 6.0 vs. 13.0 mmol/l respectively). Specimen obtained from patients on statin therapy revealed less atheromatous plaques (41% vs. 29%; p=0.02). Heavy macrophage staining was present in 66% of atorvastatin treated patients compared to 47% for patients not using statins (p=0.01). This was not accompanied by an increase in MMP-2, MMP-8 and MMP-9 levels. Patients receiving statins had significantly more often hypertension (71% vs. 59%), diabetes (25% vs. 13%) and history of coronary intervention (28% vs. 11%) than controls. However, since these factors were not associated with plaque characteristics, confounding was not considered. Conclusion Patients on statin therapy revealed a decreased amount of lipid pool in their carotid plaques. In atorvastatin treated patients this was accompanied by increased macrophage content. However, protease activity did not increase despite the significant increase in inflammatory cells pointing to an inhibitory effect of statins on protease activity.

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