Myocardial Ischemia Without Obstructive Coronary Stenoses

All-comer patients referred for coronary physiological assessment with pressure-flow measurements and acetylcholine endothelial function test, aimed to investigate different aspects of non-obstructive coronary artery disease, will be enrolled. Coronary hemodynamics during adenosine or acetylcholine evaluation will be measured either with a physiology wire equipped with pressure and temperature sensors (Abbott), or with a physiology wire equipped with pressure sensor and Doppler (Philips). Non-endothelium-dependent functional assessment will be performed with intravenous or intracoronary adenosine administration following the standard practice. Endothelium-dependent functional assessment will be performed with intracoronary acetylcholine bolus administration following the standard practice, which includes continuous 12-lead ECG monitorization. Microcirculatory dysfunction and vasomotor disorders will be diagnosed according to the criteria from the last European expert consensus on Ischaemia with Non-Obstructive Coronary Arteries (INOCA). Medical therapy will be adjusted on the basis of physiology study results and patients will be followed at 30 days, 1-, 2- and 5-years either at the outpatient clinic or by telephone contact. The Seattle Questionnaire of Angina will be applied during follow-up for obtaining an objective characterisation of the angina status.

OBJECTIVES OF THE STUDY:

• To investigate the coronary hemodynamics across the spectrum of coronary microcirculatory dysfunction.
• To investigate the coronary hemodynamics across the spectrum of vasomotor disorders.
• To investigate the impact of coronary microcirculatory dysfunction on clinical outcomes and patient symptoms at long-term follow-up.
• To investigate the impact of coronary vasomotor disorders on clinical outcomes and patient symptoms at long-term follow-up.
• To investigate the impact of a stratified medical therapy (guided by invasive physiology study) on patient symptoms.
• To investigate the role of microcirculatory dysfunction and vasomotor disorders in different settings of ischemic heart disease (i.e., recurrent angina despite successful percutaneous coronary intervention; myocardial infarction without obstructive coronary artery disease; left ventricular dysfunction (either systolic or diastolic) with or without heart failure).
• To develop new, alternative methods aimed to assess the coronary microcirculation.
• To investigate the role of myocardial bridging on myocardial ischemia generating mechanisms.
• To document safety of intracoronary testing in routine clinical practice.

Inclusion criteria

• Written informed consent available.
• Age ≥ 18 years.
• Patient eligible for invasive physiological assessment with adenosine and / or acetylcholine.

Exclusion criteria

• Hemodynamic instability.
• Anticipated technical issues for physiology wire measurements.
• Culprit vessel of acute coronary syndrome
• Contraindications for adenosine administration.
• Contraindications for acetylcholine test.
• Reduced life expectancy (less than 1 year).