Successful Prasugrel Rescue Therapy in Clopidogrel Resistant Patients Who Had Recurrent Stent Thrombosis of Drug-Eluting-Stent: The Role of Prasugrel in Clopidogrel Nonresponders
A 58-year-old non-smoker male who had no specific medical history visited the emergency room with typical angina on April 2006. Coronary angiographic findings showed significant narrowing at 3 major epicardial arteries (). Percutaneous coronary intervention with 3.0×23 mm-sized sirolimus-eluting stent (CYPHER®; Cordis Corp., Miami Lakes, FL, USA) at the mid portion of the left anterior descending artery (m-LAD) and 2.75×18 mm-sized sirolimus-eluting stent at the distal portion of left circumflex artery (d-LCx) were performed (). He received triple antiplatelet drugs (aspirin 100 mg daily, clopidogrel 75 mg daily, cilostazol 100 mg twice daily). After that, cilostazol and clopidogrel were discontinued on July 2006 (3-month use) and on June 2009 (37-month use), respectively. Three weeks after clopidogrel discontinuation, he felt typical angina and was diagnosed with non-ST-segment-elevated myocardial infarction (creatine kinase-MB 5.64 ng/mL, Troponin-T 0.019 ng/mL). On the coronary angiography, intraluminal thrombi in the distal portion of m-LAD stent and totally occluded d-LCx stent were noted (). Percutaneous coronary intervention with 3.0×20 mm-sized balloon was performed on m-LAD and d-LCx stents as well as on the distal portion of LAD. Thereafter, triple antiplatelet therapy, including cilostazol 100 mg twice daily, was restarted. The patient had no further chest pain and cilostazol and clopidogrel were discontinued on March 2010 (9-month use) and on June 2010 (12-month use), respectively.\nHowever, he visited the emergency room again on Jan 2011 because of a severe ongoing chest pain. Electrocardiogram showed ST elevation (>1 mm) on the anterior (V 1-3) lead. Emergency coronary angiography was performed and both m-LAD and d-LCx stents were totally obstructed on the angiogram (). Thrombus aspiration (Thrombuster II; Kaneka Medix Corporation, Osaka, Japan) and balloon dilation with 3.0×15 mm-sized balloon were performed on both m-LAD and d-LCx stents (). Because of the drop of blood pressure during the procedure (80/50 mm Hg), intraaortic balloon pump (AutoCAT2 WAVE-Fiber Optic; Arrow International Inc., Reading, PA, USA) and percutaneous cardiopulmonary support (CAPIOX EBS; Terumo Corporation, Tokyo, Japan) were applied. Transthoracic echocardiogram was performed right after the procedures showed a reduced left ventricular ejection fraction of 25% with anterior and anteroseptal wall akinesis. Triple antiplatelet therapy was conducted again. After that, the patient was stable and all the other devices were removed; he was sent to the general ward. However, thirteen days post procedure, he experienced a severe resting pain again. The resting electrocardiogram showed a ST segment elevation on V 1-6 leads. On the emergency angiogram, previously treated LAD and LCx stents were occluded again ().\nPercutaneous coronary intervention with 3.0×13 mm-sized balloon was performed on m-LAD and d-LCx stents (). Due to suboptimal revascularization flows, 3.0×30 mm-sized zotarolimus-eluting stent implantation (Endeavor® Sprint; Medtronic Cardio-Vascular, Minneapolis, MS, USA) was performed on m-LAD. The day before the last event, the platelet function test with Verify-Now-P2Y12® rapid analyzer (Accumetrics Inc., San Diego, CA, USA) showed inadequate platelet inhibition results {280 P2Y12-receptor Reaction Units (PRU), 14% inhibition}.\nFinally, clopidogrel was switched with prasugrel 10 mg daily followed by a 60 mg loading. Six days later, the platelet function test showed an adequate platelet inhibition (9 PRU, 98% inhibition). After discharge, cilostazol was discontinued on May 2011 (4-month use) and the platelet function test still showed a good response to the dual antiplatelet with aspirin and prasugrel (92 PRU, 70% inhibition). After a nine-month follow-up, the coronary angiography showed a patent both in LAD and LCx stents. Currently, dual antiplatelet drugs with aspirin and prasugrel were maintained without any chest pain (13-month use) ().