ABSTRAK
Latar Belakang. Pada penderita APTS/IMA-NEST, agregasi platelet dianggapsebagai faktor penyebab kejadian trombosis dan disfungsi mikrosirkulasi melaluimekanisme embolisasi distal. Pemeriksaan fungsi platelet berperan dalam menilaiderajat inhibisi platelet oleh pemberian antiplatelet khususnya clopidogrel.Tujuan. Menilai hubungan antara reaktivitas platelet dalam terapi clopidogrealdengan kejadian obstruksi mikrovaskular pada penderita APTS/IMA-NEST.Metode. Penelitian potong lintang dilakukan untuk menilai hubungan reaktivitasplatelet pada terapi clopidogrel dengan kejadian obstruksi mikrovaskular padapenderita APTS/IMA-NEST yang menjalani tindakan intervensi perkutan.Pengukuran nilai reaktivitas platelet dilakukan sebelum tindakan IKP minimal 6jam pasca loading dose clopidogrel 300 mg. Penilaian obstruksi mikrovaskulardiukur dengan myocardial blush grade (MBG) setelah intervensi koronerperkutan.Hasil. Total sebanyak 96 orang pasien yang memenuhi kriteria inklusi penelitianselama periode Mei-Oktober 2012. Sebanyak 21 subjek (21.9%) dikategorikansebagai non responder dengan nilai reaktivitas platelet ≥ 47 U, sementarasebanyak 75 subjek (78.1%) dikategorikan sebagai responder (< 47U). Reratanilai reaktivitas platelet pada kelompok non responder 63.8±18.4 U berbanding28.3±10.34 U pada kelompok responder (p=0.000). Berdasarkan nilai myocardialblush grade, kelompok subjek dengan nilai MBG 0-1 ditemukan sebanyak 12subjek (12.5%) sementara kelompok subjek dengan nilai MBG 2-3 sebanyak 84subjek (87.5%) dengan rerata nilai reaktivitas platelet 47±26.3 U berbanding35.5±19.6 U (p=0.00). Terdapat perbedaan antara kedua kelompok terhadap skorGRACE ≥ 140 (75% vs 89,3%,p=0.17), tipe lesi ACC/AHA (58,4% vs33.4%,p=0.11), aliran TIMI (50% vs 2.3%, p=0.000), dan jumlah non responder (58.3%vs 16.6%, p=0.004). Melalui analisis multivariat, nilai reaktivitas platelet padaterapi clopidogrel memiliki hubungan dengan kejadian obstruksi mikrovaskulardengan odds ratio (OR) 6.8 (IK 95%:1,8-25.4, p=0.004).Kesimpulan. Terdapat hubungan antara nilai reaktivitas platelet pada terapiclopidogrel dengan kejadian obstruksi mikrovaskular pada penderita IMA-NESTyang menjalani tindakan IKP dalam masa perawatan di rumah sakit.

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ABSTRACT
Background. In the setting of UA/NSTEMI, platelet aggregation has a pivotalrole in trombosis and microcirculation dysfunction resulting from distalembolization, and the rate of microcirculation dysfunction will increase byiatrogenic plaque rupture during PCI. Platelet function tests has been widely usedto measure platelet inhibition level on antiplatelet therapy, particularly onclopidogrel.Objective. This study aimed to evaluate the association between plateletreactivity on clopidogrel treatment with microvascular obstruction after PCI inUA/NSTEMI patients.Method. A cross sectional study was conducted to evaluate the associationbetween platelet reactivity on clopidogrel treatment and microcvascularobstruction after PCI in UA/NSTEMI patients. Platelet reactivity was measuredbefore PCI minimal 6 hours after loading dose 300 mg clopidogrel, whilemicrovascular obstruction was evaluated by myocardial blush grade (MBG).Results. Out of 96 subjects examined during May to October 2012, 21 subjects(21.9%) was categorised as non responder (≥47 U) and 75 subjects (78.1%) asresponder (<47 U). Mean platelet reactivity in non responder group was 63.8±18.4U versus 28.3±10.34 U in responder group (p=0.000). Based on myocardialblush, MBG 0-1 was found in 12 subjects (12.5%) while MBG 2-3 was found in84 subjects (87.5%). There were difference in both groups on GRACE risk score≥ 140 (75% vs 89,3%,p=0.17), ACC/AHA type lesion (58,4% vs33.4%, p=0.11),TIMI flow (50% vs 2.3%, p=0.000), and number of responder subjects (58.3% vs16.6%, p=0.004) with mean platelet reactivity 47±26.3 U vs 35.5±19.6 U,respectively (p=0.00). Multivariate analysis showed that platelet reactivity onclopidogrel treatment is persistently associated with microvascular obstruction(OR 6.8, CI: 1,8-25.4, p=0.004).Conclusion. In this study, platelet reactivity on clopidogrel treatment isassociated with microvascular obstruction after stenting in UA/NSTEMI patients.