During primary PCI, stent deployment and post-dilatation are associated with no-reflow. The mechanisms for no reflow include distal embolization of thrombus, enhanced thrombus formation and vascular spasm. No reflow is associated with risk factors such as prolonged duration of ischaemia, heavy thrombus burden, persistent ST elevation and long stent length. ACTIVE HYPOTHESIS: once normal antegrade flow has been re-established with initial aspiration thrombectomy and/or balloon angioplasty at the beginning of primary PCI, compared with usual care with direct stenting, a strategy of deferred stenting for 4 -16 hours to permit the beneficial effects of normalized coronary blood flow and anti-thrombotic therapies will reduce the incidence of no reflow in at-risk STEMI patients. DESIGN: In consecutive STEMI patients with risk factors for no reflow and who have given informed consent, when normal flow has been established (TIMI 3) by initial aspiration thrombectomy and/or balloon angioplasty, participants will be randomized to deferred stenting or usual care with direct stenting. All patients will receive dual anti-platelet therapy. Patients who are randomized to deferred stenting will receive intravenous glycoprotein IIbIIIa inhibitor and anti-coagulation with low molecular weight heparin. Patients who are screened and not eligible to be randomized will be prospectively entered into a registry. Study assessments for feasibility, safety and efficacy will be prospectively performed. An independent clinical event committee will review all serious adverse events. Study endpoints will be subject to core laboratory analyses. The study is intended to inform the design of a larger multicentre clinical trial.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
SINGLE
Enrollment
101
Golden Jubilee National Hospital
Clydebank, Glasgow, United Kingdom
Incidence of angiographic no-reflow/ slow-reflow (TIMI flow grade < 3) in the deferred and conventional treatment groups
Time frame: Asessed during the 1st (both groups) and 2nd procedures (deferred group) (0-16 hours)
Extent of late microvascular obstruction (MVO) assessed by cardiac MRI
Time frame: MRI 2-5 days post randomisation
Clinical events (hospitalisation for heart failure, re-infarction, cardiac death)
Time frame: Assessed at index admission and 6-months
Degree of ST-segment resolution on ECG
Time frame: ECG in cath-lab prior to reperfusion and again 60 mins post-reperfusion
TIMI coronary arter flow grade
Time frame: At the beginning and end of the first procedure (for both groups) and at the beginning and end of the second procedure in the deferred group
Culprit vessel dimensions (QCA) and thrombus burden
Time frame: Initial coronary angiogram (and 2nd angiogram in deferred group)
Change in LV ejection fraction
Time frame: Cardiac MRI 2 days and 6-months post PCI
Index of microvascular resistance (IMR)
Time frame: Assessed following stent deployment (initial procedure for the conventional group and 2nd procedure for the deferred group)
Corrected TIMI frame count
Time frame: At the beginning and end of the first procedure (for both groups) and at the beginning and end of the second procedure in the deferred group
Angiographic tissue myocardial blush grade
Time frame: Angiographic myocardial blush grade at the end of the first procedure (both groups) and at the end of the second procedure in the deferred group
Intra-procedural thrombotic events
Time frame: Asessed during the 1st (both groups) and 2nd procedures (deferred group) (0-16 hours)
Degree of adverse remodelling (end-systolic and end-diastolic volume index)
Time frame: Cardiac MRI at 6-months
Final infarct size and myocardial salvage
Time frame: Assessed from cardiac MRI day 2-5 and cardiac MRI at 6months
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