The Impact of Post Stenting Balloon Dilatation on Coronary Microcirculation in STEMI Patients Undergoing PPCI

Suboptimal stent deployment can lead to future stent failure. Thus, optimising stent deployment with non-compliant balloons (NC balloon) post dilatation (PD) at high pressures is an established strategy. In the context of ST segment elevation myocardial infarction (STEMI), PD has been correlated anecdotally with the no reflow phenomenon.

This study aims to determine the impact of stent post-dilation (PD) with NC balloons at high pressures on coronary microcirculation during PPCI by measuring the index of microcirculatory resistance (IMR) pre and post stent post-dilatation. Pre and post PD, an optical coherence tomography (OCT) study will be performed to assess stent deployment and identify parameters that predict the changes in IMR.

Inclusion criteria

• >18 years of age
• Acute symptoms onset with duration > 20 minutes
• ST-segment elevation ≥ 0.1 mV in ≥ 2 contiguous leads, signs of a true posterior infarction or documented newly developed left bundle branch block
• Infarct related artery with a diameter above 2.5 mm
• Operator's intention to proceed to stent deployment (i.e. not refer for CABG or defer PCI)

Exclusion criteria

• < 18 year of age
• Symptoms duration > 12 hours
• Unable to give informed consent
• Previous bypass graft surgery
• Previous myocardial infarction
• Pregnancy
• Known severe chronic kidney disease (creatinine clearance ≤30 mL/min), unless the patient is on dialysis
• Unable to receive antiplatelets or anticoagulation (i.e. coagulation disorders, bleeding etc.)
• Haemodynamic instability
• Severe LMS disease
• Culprit vessel diameter < 2.5 mm
• Contraindications to adenosine
• Any study lesion characteristic resulting in the expected inability to deliver OCT catheter to the lesion pre and post PD (e.g. moderate or severe vessel calcification or tortuosity)