{"doi":"10.1160/th08-01-0033","title":"ADP-induced platelet aggregation frequently fails to detect impaired clopidogrel-responsiveness in patients with coronary artery disease compared to a P2Y12-specific assay","abstract":"<jats:title>Summary</jats:title><jats:p>Incomplete P2Y12-inhibition during clopidogrel treatment is associated with increased cardiovascular events and mortality after coronary intervention. We investigated the incidence of impaired individual clopidogrel-responsiveness using a P2Y12-specific and pre-treatment-independent assay in a real world situation. One hundred consecutive patients with coronary artery disease (CAD) on combined acetylsalicylic acid and clopidogrel treatment (75 mg/d) and 33 patients on aspirin only were screened for platelet ADP-induced signalling by conventional aggregometry, platelet P-selectin expression and the platelet reactivity index (PRI). Impaired P2Y12-specific inhibition by clopidogrel was defined as a PRI&gt;50%. Functional platelet reactivity was significantly lower in clopidogrel-treated patients compared to controls. Impaired individual response to treatment was diagnosed in 69% of clopidogrel-treated patients. Conventional assessment of maximum ADP-induced platelet aggregation failed to detect impaired P2Y12 inhibition in 36% of patients identified by PRI to have an impaired clopidogrel response. Impaired clopidogrel response was associated with lower HDL levels and a history of hyperlipidaemia. In conclusion, PRI as a P2Y12-specific assay to evaluate the treatment effect of clopidogrel in patients with CAD revealed insufficient P2Y12-inhibition in two thirds of patients in a real-world scenario indicating a markedly higher incidence than previously assumed. PRI detected significantly more patients with impaired response than conventional platelet aggregation.</jats:p>","journal":"Thrombosis and Haemostasis","year":2008,"id":665643,"datarank":0.5101796072493234,"base_score":3.4011973816621555,"endowment":3.4011973816621555,"self_citation_contribution":0.5101796072493234,"citation_network_contribution":0.0,"self_endowment_contribution":0.5101796072493234,"citer_contribution":0.0,"corpus_percentile":null,"corpus_rank":null,"citation_count":29,"citer_count":0,"citers_with_citation_signal":0,"citers_with_endowment":0,"datacite_reuse_total":0,"is_dataset":false,"is_dataset_confidence":null,"is_data_producer":false,"deposit_databanks":null,"is_oa":false,"file_count":0,"downloads":0,"has_version_chain":false,"published_date":null,"fair_score":null,"fair_percentile":null,"algorithm_id":"datarank_citation_only_1hop_v6","ranking_scope":"data_only","authors":[{"id":1738199,"name":"Ulrike Flierl","orcid":null,"position":1,"is_corresponding":false},{"id":1738200,"name":"Martin Eigenthaler","orcid":null,"position":2,"is_corresponding":false},{"id":1160441,"name":"Stefan Störk","orcid":"0000-0002-1771-7249","position":3,"is_corresponding":false},{"id":1738201,"name":"Ulrich Walter","orcid":null,"position":4,"is_corresponding":false},{"id":245420,"name":"Georg Ertl","orcid":"0000-0003-4578-5713","position":5,"is_corresponding":false},{"id":661411,"name":"Johann Bauersachs","orcid":"0000-0002-9341-117X","position":6,"is_corresponding":false},{"id":1327795,"name":"Andreas Schäfer","orcid":"0000-0003-1171-0078","position":7,"is_corresponding":false},{"id":1738197,"name":"Sarah Weinberger","orcid":null,"position":0,"is_corresponding":false}],"reference_count":0,"raw_metadata":{"has_enrichment":true,"resolved":true,"title":"ADP-induced platelet aggregation frequently fails to detect impaired clopidogrel-responsiveness in patients with coronary artery disease compared to a P2Y12-specific assay","abstract":"<jats:title>Summary</jats:title><jats:p>Incomplete P2Y12-inhibition during clopidogrel treatment is associated with increased cardiovascular events and mortality after coronary intervention. We investigated the incidence of impaired individual clopidogrel-responsiveness using a P2Y12-specific and pre-treatment-independent assay in a real world situation. One hundred consecutive patients with coronary artery disease (CAD) on combined acetylsalicylic acid and clopidogrel treatment (75 mg/d) and 33 patients on aspirin only were screened for platelet ADP-induced signalling by conventional aggregometry, platelet P-selectin expression and the platelet reactivity index (PRI). Impaired P2Y12-specific inhibition by clopidogrel was defined as a PRI&gt;50%. Functional platelet reactivity was significantly lower in clopidogrel-treated patients compared to controls. Impaired individual response to treatment was diagnosed in 69% of clopidogrel-treated patients. Conventional assessment of maximum ADP-induced platelet aggregation failed to detect impaired P2Y12 inhibition in 36% of patients identified by PRI to have an impaired clopidogrel response. Impaired clopidogrel response was associated with lower HDL levels and a history of hyperlipidaemia. In conclusion, PRI as a P2Y12-specific assay to evaluate the treatment effect of clopidogrel in patients with CAD revealed insufficient P2Y12-inhibition in two thirds of patients in a real-world scenario indicating a markedly higher incidence than previously assumed. PRI detected significantly more patients with impaired response than conventional platelet aggregation.</jats:p>","is_dataset_classified":null,"base_score":0.0,"endowment":0.0,"datacite_reuse_total":0,"file_count":0,"downloads":0,"views":0,"has_version_chain":false,"is_dataset":false,"is_oa":false,"pmid":"18841284","pmcid":null,"openalex_id":null,"authors":[],"funders":[],"total_grants":0,"fwci":null,"citation_percentile":null,"influential_citations":0,"citation_trend":[],"oa_status":"closed","license":null,"oa_locations":[{"url":"http://www.thieme-connect.de/products/ejournals/pdf/10.1160/TH08-01-0033.pdf","host_type":"publisher"}],"fields_of_study":[],"mesh_terms":["Blood Platelets","Humans","Aspirin","Ticlopidine","P-Selectin","Receptors, Purinergic P2","Adenosine Diphosphate","Platelet Aggregation Inhibitors","Flow Cytometry","Incidence","Comorbidity","Signal Transduction","Platelet Aggregation","Drug Resistance","Aged","Female","Male","Coronary Artery Disease","Receptors, Purinergic P2Y12","Clopidogrel"],"keywords":[],"sdg_mappings":[],"linked_datasets":[],"clinical_trials":[],"software_tools":[],"database_accessions":[],"source":"live","citation_network_status":"fetched"},"created_at":"2026-08-13T11:50:05.349415Z","pmid":null,"pmcid":null,"fwci":null,"citation_percentile":null,"influential_citations":0,"oa_status":null,"license":null,"views":0,"total_file_size_bytes":0,"version_count":0,"fair_f":null,"fair_a":null,"fair_i":null,"fair_r":null,"fair_zscore":null,"fair_rationale":null,"fair_model":null,"fair_agent_version":null,"fair_fulltext_source":null,"fair_has_llm":null,"fair_computed_at":null,"clinical_trials":[],"software_tools":[],"db_accessions":[],"linked_datasets":[],"topics":[]}