Elective Percutaneous Coronary Intervention With or Without Supplemental OXYgen and Evaluation of Effects on Coronary Microcirculation Using the Index of Microcirculatory Resistance

Aim:

The aim of the EPOXY-IMR trial is to evaluate the effect of supplemental oxygen on coronary circulation in the setting of elective coronary angiography and percutaneous coronary intervention (PCI). To achieve this, different functional parameters such as the index of microcirculatory resistance (IMR), fractional flow reserve (FFR) and coronary flow reserve (CFR) will be obtained and serial biomarkers (cardiac troponin) will be analyzed.

Background:

Coronary artery disease (CAD) based on arteriosclerotic narrowing of the coronary blood vessels is the most common cause of death in the western world. To determine the severity of the disease in symptomatic patients and guide optimal therapy, coronary angiography is frequently performed. Simplified, three outcomes can be found:

1. No or mild evidence of CAD leading to continuous medical therapy.
2. Severe disease demanding revascularization therapy done by either percutaneous coronary intervention (PCI), where most commonly balloon dilatation followed by placement of a metal stent in the coronary vessel is performed, or coronary artery bypass grafting (CABG).
3. In patients with moderate disease further functional testing is required to assess the gravity of the narrowing. This can be achieved by placing a pressure sensor equipped guide wire to the diseased artery comparing blood pressure proximal and distal to the stenosis during hyperemia, known as Fractional Flow Reserve (FFR). Although based on pressure recordings, FFR is a highly accurate measure of the flow limitation of a given stenosis. A common cut-off value of 0,8 is used where a lower value mandates therapy as in patients with severe disease.