Additional Benefit of Cilostazol to Dual Antiplatelet Therapy After BioMatrix Stent Implantation (ABCD)

• Composite of cardiac death from vascular causes, myocardial infarction, ischemia driven target lesion revascularization [ Time Frame: One year ] [ Designated as safety issue: No ]
  Primary endpoint in this study will be the time to first occurrence of any event from the composite of cardiac death from vascular causes, myocardial infarction, ischemia driven target lesion revascularization for 1 year from the randomization. This outcome measure is used as the basis for the sample size calculation. Once randomized, all subjects will be assessed for the primary composite efficacy endpoint until study closure unless informed consent is withdrawn for study participation.
  
  

• Individual components of safety and efficacy issue [ Time Frame: One year ] [ Designated as safety issue: Yes ]

  Secondary efficacy endpoints: cardiac death, Q or non-Q MI, Ischemic-driven TVR, Ischemic-driven TLR, Stent thrombosis by ARC definition.

  Secondary safety endpoints: Clinically significant bleeding defined as TIMI major or TIMI minor bleeding, study drug adverse effect, rate of early cessation of study drug.

  
  

Previous randomized trials have shown the efficacy of drug-eluting stent (DES) such as sirolimus-eluting stent (CYPHERTM, Cordis, Warren, NJ, USA), paclitaxel-eluting stent (TAXUSTM, BostonScientific, Natick, MA, USA), and zotarolimus-eluting stent (Endeavor,Medtronic,Minneapolis, MN, USA) over bare metal stents (BMS) in reducing neointimal hyperplasia, late luminal loss, and angiographic restenosis leading to decreased target lesion revascularization.1-4 In addition, Among patients with off-label indications, the use of DESs reduced a rate of repeat revascularization without increasing the risk of death or myocardial infarction, as compared with bare-metal stents.5 But, compared with on-label use, off-label use of DESs is associated with a higher rate of adverse outcomes such as death, myocardial infarction and target vessel revascularization. Furthermore, stent thrombosis (ST) occurred predominantly in patients who underwent off-label DES implantation.6 It is known that the risk of adverse cardiac events and ST after DES implantation is related to stent length.7 Cilostazol is a potent phosphodiesterase III inhibitor preventing the hydrolysis of cAMP in platelets and vascular smooth muscle cell. The novel mechanism of action of cilostazol reduces the number of circulating, partially activated, or pre-conditioned platelets, by reducing the surface expression of adhesive molecules in endothelial cells interacting with circulating platelets. The agent also directly inhibits platelet aggregation induced by a variety of stimuli, including arachidonic acid, ADP, collagen, thrombin, and high shear stress.8 In current guidelines, a 12-month duration of dual antiplatelet therapy with aspirin and clopidogrel is recommended after DES implantation.9 But, recent meta-analyses showed a potential benefit of cilostazol in addition to dual antiplatelet therapy in reducing angiographic restenosis and improved clinical outcomes after BMS or DES implantation.10, 11 Actually, additional cilostazol to dual antiplatelet therapy showed reduced restenosis and late loss in patients with long coronary lesion and diabetes with multi-vessel coronary artery disease and it also showed beneficial effect on stent thrombosis after DES implantation.12-14 Although most studies showed no difference in bleeding according to additional cilostazol to dual antiplatelet therapy, the rate of early cessation of cilostazol due to adverse effect including headache, palpitation, skin rash and hepatic dysfunction was about 15%.12-14 Because of relatively higher side effect rate and no definitive duration of addition cilostazol use, we expect that cilostazol with short duration can be easily accepted to patient. Although almost studies about cilostazol after stent implantation used a 6- month duration of cilostazol, one study showed that use of cilostazol for 3 months after percutaneous transluminal coronary balloon angioplasty reduced restenosis and revascularization, as compared with use of aspirin.15 So, we expect a 3-month use of additional cilostazol to dual antiplatelet therapy can reduce the adverse outcome and ST after stent implantation without increasing early cessation of cilostazol.

The BioMatrixTM stent system (Biosensors Interventional Technologies Pte., Ltd, Singapore) consist of a stainless steel, quadrature-link design, balloon expandable S-StentTM, and a polylactic acid (PLA) polymer and BiolimusA9® coating mounted on a low-profile delivery catheter.16, 17 It is expected that abluminal biodegradable coating of BioMatrixTM stent can lead to more targeted drug release, reduced systemic exposure and early BMS-like endothelial coverage.18 The first-in-man, randomized controlled SEALTH I trial demonstrate higher efficacy of BioMatrixTM stent by showing lower late lumen loss and in-stent restenosis as compared with BMS, S-stent at 6-month follow-up.19 In LEADERS trial, BioMatrixTM stent showed similar efficacy and safety as compared with sirolimus-eluting stent in patients with chronic stable coronary artery disease and acute coronary syndromes.20 But significantly lower uncovered and malapposed struts was detected by optical coherence tomography study.21 This means more complete coverage of struts and we can expect lower late ST after BioMatrixTM stent implantation.