The effect of carotid stenting on rheological parameters, free radical production and platelet aggregation.

INTRODUCTION

Carotid artery stenting has become a possible treatment of significant carotid stenosis. The risk of stent occlusion and restenosis might be increased by abnormal rheological conditions amplified platelet aggregation and free radical production during the operation.

AIMS: The aim of our study was to assess the changes in hemorheological parameters, platelet aggregation, and catalase activity after endovascular treatment of carotid stenosis.

METHODS

18 patients (11 men, ages 68 +/- 9 years and 7 women, ages 62 +/- 8 years) suffering from significant carotid stenosis and treated with carotid endovascular intervention were examined. Alteration in hemorheological parameters as well as epinephrine-, ADP-, and collagen-induced platelet aggregation were evaluated. Antioxidant reserve was characterized by the determination of catalase activity. The measurements were carried out directly before and after the procedure and 1, 2, 5 days and 1 month following the intervention. Preceding the operation the patients were administered a maximum dose (300 mg) of clopidogrel.

RESULTS

Hematocrit, plasma fibrinogen concentration (PFC) and whole blood-, and plasma viscosity values (WBV and PV) significantly decreased immediately after stenting (p<0.001). By the fifth day following the intervention the PFC, WBV, PV, red blood cell (RBC) aggregation and ADP-induced platelet aggregation significantly increased (p<0.0001) compared to values measured postprocedurally. At 1 month follow-up these parameters, except whole blood viscosity, decreased significantly compared to measurements made on the 5th day. On the other hand, catalase activity showed significant elevation by the end of the first month.

CONCLUSION

Hemorheological parameters and platelet aggregation showed specific changes following carotid stenting. Abnormal changes of the rheological conditions and increasing platelet activation are the most pronounced in the first week following stenting, which may lead to early stent occlusion. Oxidative stress production returned to baseline levels only by the end of the first month.