Deferred Stent Trial in STEMI

Randomised Controlled Study to Assess Whether Deferred Stenting in Acute STEMI Patients Might Reduce the Incidence of No-reflow Versus Conventional Treatment With Immediate Stenting

British Heart Foundation, University of Glasgow, Health Sciences Scotland, Chief Scientist Office, Scottish Government

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.

During primary PCI in STEMI, when TIMI 3 flow has been re-established with guide-wire, aspiration thrombectomy and/or balloon angioplasty, stenting is then deferred for a period of 4-16 hours following reperfusion. During this time, patients remain in the Coronary Care Unit and will receive intravenous tirofiban and subcutaneous low molecular weight heparin (enoxaparin 1 mg/kg)

Incidence of angiographic no-reflow/ slow-reflow (TIMI flow grade < 3) in the deferred and conventional treatment groups

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

Assessed following stent deployment (initial procedure for the conventional group and 2nd procedure for the deferred group)

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 myocardial blush grade at the end of the first procedure (both groups) and at the end of the second procedure in the deferred group

Bleeding events related to vascular access or non-access site bleeding. Bleeding was defined according to the ACUITY criteria: major bleed = intracranial or intraocular bleeding; bleeding at the site of angiography requiring intervention; a hematoma of 5 cm in diameter; a reduction in hemoglobin level of at least 4 g/dL in the absence of overt bleeding or 3 g/dL with a source of bleeding; or transfusion.

Contrast-induced nephropathy was defined as either a greater than 25% increase of serum creatinine or an absolute increase in serum creatinine of 0•5 mg/dL after a radiographic examination using a contrast agent.

Inclusion Criteria: Rescue PCI Prolonged ischaemic time (> 12hours) Previous MI Age > 65 Occluded artery (TIMI 0/1) at initial angiography Thrombus burden (TIMI grade 2+) Long plaque/ stent length (> 24 mm) Severe coronary artery disease (e.g calcified artery) Small reference vessel diameter (< 2.5 mm) Persistent ST-elevation (> 50%) following reperfusion Index of microvascular resistance (IMR) > 40 Exclusion Criteria: Absence of normal coronary flow (TIMI 3)

Carrick D, Oldroyd KG, McEntegart M, Haig C, Petrie MC, Eteiba H, Hood S, Owens C, Watkins S, Layland J, Lindsay M, Peat E, Rae A, Behan M, Sood A, Hillis WS, Mordi I, Mahrous A, Ahmed N, Wilson R, Lasalle L, Genereux P, Ford I, Berry C. A randomized trial of deferred stenting versus immediate stenting to prevent no- or slow-reflow in acute ST-segment elevation myocardial infarction (DEFER-STEMI). J Am Coll Cardiol. 2014 May 27;63(20):2088-2098. doi: 10.1016/j.jacc.2014.02.530. Epub 2014 Feb 27.

Gao H, Aderhold A, Mangion K, Luo X, Husmeier D, Berry C. Changes and classification in myocardial contractile function in the left ventricle following acute myocardial infarction. J R Soc Interface. 2017 Jul;14(132):20170203. doi: 10.1098/rsif.2017.0203.