Efficacy and Safety Study of Deferred Stenting in Patients With STEMI
Condition: ST-segment Elevation Myocardial Infarction
MeSH terms: Myocardial Infarction; ST Elevation Myocardial Infarction; Infarction
Study type: Interventional

Summary: 
      It is known that no reflow phenomenon by microvascular obstruction after revascularization in
      STEMI increase infarct size, cardiac remodeling, and a risk of late mortality. Major
      mechanism of microvascular obstruction is distal embolization during procedure. Some
      investigators showed deferred stenting decreased the degree of microvascular obstruction
      compared with immediate stenting in STEMI. The aim of current study is to compare impact of
      immediate stent implantation versus deferred stent implantation on infarct size and
      microvascular perfusion in patients with ST-segment elevation myocardial infarction (STEMI).
    

Detailed description: 
      1. Patients will be enrolled if they agree to participate in the study and sign informed
           consent among patients who are satisfied with inclusion and exclusion criteria.
           Acceptance of the study will be taken concurrently at the situation when the patient
           admitted via emergency department with the diagnosis of STEMI and informed consent of
           primary coronary angiography and intervention is taken. Considering emergent situation
           of the procedure, it is thought to be impossible to take informed consent of the study
           before procedure and after achieving TIMI flow. Duty operator will inform to the patient
           when taking informed consent of primary coronary angiography and intervention that the
           patient will be randomized to immediate coronary stenting group or deferred coronary
           stent group, and explain about theoretical background of deferred coronary stenting. To
           all patients, aspirin 300㎎, clopidogrel 600㎎ are administered orally and heparin
           intravenously until achieving ACT (activated clotting time) between 200 and 250 seconds.
           Maximal total dose of unfractionated heparin of 100 unit/㎏ will be administered before
           intervention.

        2. Transradial or transfemoral approach will be determined on operator's decision. Flow of
           the infarct related artery (IRA) will be checked as total occlusion, TIMI 0, Ⅰ or Ⅱ
           after coronary angiography.

        3. Abciximab (0.25㎎/㎏) intracoronary injection will be performed to all possible patients
           after guidewire has passed culprit lesion. Additional manual thrombus aspiration or
           balloon angioplasty can be performed by operator to achieve TIMI Ⅲ flow. When TIMI Ⅲ
           flow is achieved after these procedures, patient will be randomized to immediate
           stenting or deferred stenting group.

        4. Although stent implantation without balloon angioplasty is preferred in immediate
           stenting group, balloon angioplasty can be performed to achieve distal flow. In deferred
           stenting group, second stage procedure (stent implantation) will be done at 5 to 7 days
           after TIMI Ⅲ flow has achieved.

        5. On coronary intervention (stent implantation), all possible cases will be implanted with
           Nobori Biolimus A9-eluting coronary stent (Terumo, Tokyo, Japan). (Other stents can be
           used if the length of the lesion cannot be covered with Nobori stent.)

        6. In both group, abciximab continuous intravenous infusion on a dose of 0.125 ㎍/㎏/min
           (maximum dose 10 ㎍/min) will be done after initial procedure if possible. (Intracoronary
           injection and intravenous infusion of abciximab should be done unless there is no
           contraindication of abciximab.)

        7. In both group, subcutaneous enoxaparin (low molecular weight heparin) injection will be
           done twice daily until 3 days after procedure if possible. In case of stent implantation
           in the fifth to seventh day within deferred coronary stenting group, enoxaparin
           injection can be extended until deferred intervention.

        8. Transradial and transfemoral approach are all possible. If procedure is done with
           transfemoral approach, sheath removal will be done after continuous intravenous
           abciximal infusion of 12 hours and enoxaparin injection after hemostasis has been
           confirmed.

        9. In case of residual stenosis of IRA is below 30% within deferred coronary stenting
           group, intravascular ultrasonography (IVUS) will be performed at the secondary procedure
           and withdrawal of stenting can be done upon operator's discretion.

       10. In case of multivessel disease, intervention of non-IRA will be deferred in both groups.
           Therefore, PCI on IRA and non-IRA will be done concurrently in deferred coronary
           stenting group.

       11. Patient will maintain dual antiplatelet therapy of aspirin 100㎎ and clopidogrel 75㎎
           after PCI.

       12. Among prescribed drugs after PCI, statin agent can be used upon operator's discretion.

       13. Cardiac MRI is done on the period of 30±7 days after diagnosed as STEMI in both group.

       14. Follow-up period is 1 month ± 1 week, 6 month ± 4 week, and 12 month ± 4 week in both
           group. Transthoracic echocardiography will be done at 6 month ± 4 week follow-up period.
    

Intervention name(s): Deferred coronary stenting; Immediate coronary stenting
Intervention type(s): Procedure; Procedure
Intervention description(s): Abciximab (0.25㎎/㎏) intracoronary injection will be performed to all possible patients after guidewire has passed culprit lesion. Additional manual thrombus aspiration or balloon angioplasty can be performed by operator to achieve TIMI Ⅲ flow. When TIMI Ⅲ flow is achieved after these procedures, patient will be randomized to immediate stenting or deferred stenting group. In deferred stenting group, second stage procedure (stent implantation) will be done at 5 to 7 days after TIMI Ⅲ flow has achieved.; Abciximab (0.25㎎/㎏) intracoronary injection will be performed to all possible patients after guidewire has passed culprit lesion. Additional manual thrombus aspiration or balloon angioplasty can be performed by operator to achieve TIMI Ⅲ flow. When TIMI Ⅲ flow is achieved after these procedures, patient will be randomized to immediate stenting or deferred stenting group. In immediate stenting group, stenting will be done immediate after achieving TIMI III flow during initial procedure.
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: None (Open Label)
Primary purpose: Treatment