Abstract

Background: Failure to reach the level of therapeutic anticoagulation represents a risk factor for occlusive events in patients suffering from peripheral arterial disease. Our study aimed to analyze the prevalence of nonresponse to dual antiplatelet therapy in a group of patients admitted to our hospital with critical limb ischemia (CLI) following stent-thrombosis.
Methods: This prospective study was approved by the local Ethics Review Board. Patients with critical limb ischemia following stent thrombosis were included if dual antiplatelet therapy consisting of 100 mg aspirin and 75 mg clopidogrel per day had been administered over three months prior to enrollment. The antiaggregatory effects were analyzed using the Multiple Electrode Aggregometry (MEA, Multiplate®, Roche AG, Grenzach, Germany). The primary endpoints were the area under the aggregation curve (AUC) of the ex-vivo-induced platelet aggregation following stimulation with adenosine diphosphate (ADP, ADPtest) and arachidonic acid (ASPItest).
Results: Sixty patients were enrolled in this study. Platelet aggregation was 39.6 (24/54) [median (25th/75th percentile)] U in the ADPtest and 22.4 (13/35) U in the ASPItest. Effective aspirin- and ADP-induced therapeutic inhibition of platelet aggregation was confirmed in 78% and 53% of our patients, respectively. Effective dual platelet inhibition was achieved in 27 patients (45%). A non-response to both of the antiaggregatory drugs was found in 14% of the patients.
Conclusions: The results of the present study indicate a high prevalence of nonresponse to antiaggregatory medication in our study collective. Further studies are needed to confirm our hypothesis that individual adjustments of both aspirin and clopidogrel dosages may potentially reduce the incidence of CLI in patients suffering from peripheral arterial occlusive disease.

DOI: 10.7754/Clin.Lab.2013.131007