The Effect of GRAVITY on Physiological Measurements During Invasive Coronary Angiography and Intervention

The study will contain two groups:

Group 1 - stable elective patients with stenotic coronary arteries. These patients are referred as outpatients for a 'pressure wire' test.

Group 2 - stable elective patients with a chronic total occlusion of an artery (CTO). The artery will be either the left anterior descending artery (LAD) or right coronary artery (RCA)

Group 1 - 30 patients

Patients will be recruited from referrals to the centre for a pressure wire study. Participants will be screened for eligibility using the protocol inclusion and exclusion criteria. Study information will be given and informed consent obtained.

Patients will start the procedure prone. A physiology wire will be placed in the artery of interest and measurements taken. Patients will then be turned into the standard supine position with repeat measurements. The study is now completed. The usual pressure measurements will be taken and used to guide treatment as per standard protocol.

Group 2 - 20 patients

Patients will be recruited from referrals to the centre for a percutaneous coronary intervention (PCI) to a chronic total occlusion (CTO). Participants will be screened for eligibility using the protocol inclusion and exclusion criteria. Study information will be given and informed consent obtained.

Patients will undergo CTO PCI as per standard procedure. Once completed, the vessel will be occluded using balloon inflation. Physiological measurements will be taken distal to the occluded balloon. The patient will then be turned prone and repeat measurements again with balloon occlusion will be taken.

This group will have MRI scanning as part of standard care before the procedure. The study will carry out a further MRI, this time in the prone position before PCI as part of the study protocol

Group 1

Inclusion criteria

• Age > 18 years of age
• Angina symptoms or evidence of myocardial ischaemia
• Stenosis >50% in LAD or RCA on coronary angiogram or CT coronary angiogram
• Participant is willing and able to give informed consent
• Eligible for PCI

Exclusion criteria

• Previous CABG with any patent grafts
• Significant left main stem stenosis
• Lesion of interest in Circumflex artery
• Haemodynamic Instability
• Unable to consent
• Unable to receive dual antiplatelet therapy
• Contraindication to adenosine
• Recent acute coronary syndrome (ACS) (<48 hours)
• Pregnancy
• Unable to lie prone
• Severe valvular heart disease or cardiomyopathy

Group 2

Inclusion criteria

• Age >18 years of age
• Stable angina / ischaemic symptoms / and / or
• Evidence of viability and /or ischaemia in the chronic total occlusion (CTO) territory
• Participant is willing and able to give informed consent.
• Presence of chronic total occlusion (CTO) in LAD or RCA
• Eligible for PCI to a chronic total occlusion (CTO)

Exclusion criteria

• Previous CABG with any patent grafts
• Significant left main stem stenosis
• Dominant collateral supply from circumflex artery
• Both LAD and RCA occluded
• Haemodynamic instability
• Unable to receive antiplatelet therapy
• Contraindication to adenosine
• Recent ACS (<48 hours)
• eGFR<40
• Pregnancy
• Severe valvular heart disease or cardiomyopathy
• Contraindication to Cardiac MRI
• Unable to lie prone