Comparison of a Fully Angiography-Derived Versus a Hybrid of Angiography and Pressure-Wire-Derived Approach to Assess Coronary Microvascular Resistance: The Oxford Acute Myocardial Infarction Hybrid (OxAMI-HYBRID) Study.
Chai J., Marin F., Scarsini R., Kotronias R., Benenati S., Chu M., Couch LS., Langrish J., OxAMI Investigators None., Channon K., Banning A., De Maria GL.
BACKGROUND: Despite growing evidence of its clinical implications, assessment of coronary microvascular dysfunction (CMD) remains limited in routine clinical practice. Hence, there is an increasing interest in angiography-derived indices to encourage assessment of CMD in the cardiac catheterisation laboratory. AIMS: We investigate here an alternative approach, using a combination of pressure-wire-based assessment of distal coronary pressure (Pd) and an angiography-derived surrogate of coronary flow, to derive a hybrid index of microcirculatory resistance (IMRhybrid). METHODS: Patients enroled prospectively under the Oxford Acute Myocardial Infarction (OxAMI) study were included in the OxAMI HYBRID substudy. The accuracy of IMRhybrid was assessed in diagnosing CMD using bolus thermodilution-based Index of Microcirculatory Resistance (IMR) as a reference. The accuracy of IMRhybrid was then compared against a fully angiography-derived index of microvascular resistance (IMRangio). RESULTS: One hundred and eighty six patients were enroled, of which 121 with acute coronary syndrome and 65 with stable coronary artery disease. A total of 240 vessel analyses were performed. Both IMRhybrid and IMRangio correlated with IMR (rho = 0.71, p