Boston Scientific COMET Wire Validation Study

Given the following key points of evidence, the optimal management of chest pain patients who come to diagnostic coronary angiography would more often be achieved if there was concomitant data with regard to the presence of patient-specific and lesion-specific ischaemia:

• that it is the presence and extent of reversible myocardial ischaemia (RMI) that dominates over coronary anatomy as a predictor of near term cardiovascular events, as well as symptom relief
• that prognostic benefit after revascularisation is greatest in patients with the largest pre-procedure ischaemic burden
• that intra-coronary pressure wire (PW) data are strongly correlated with subsequent cardiac events despite the binary nature of the test
• that stenting of coronary lesions that are PW negative has a worse outcome than optimal medical therapy (OMT)
• that PW-directed percutaneous coronary intervention (PCI) in multivessel disease is associated with a better clinical outcome than angiogram-directed PCI despite fewer treated lesions and less stents
• that PW-directed PCI improves prognosis compared to OMT
• that mismatch exists in up to 30-40% of lesions encountered at angiography between the visual appearance of the severity of the lesion and whether the lesion is "ischaemic" (and therefore a target for revascularisation) according to PW.

The availability of PW has been shown to have had a substantial effect on overall management of patients undergoing diagnostic coronary angiography (ie when options are still OMT/PCI and coronary artery bypass grafting (CABG) in several observation studies including RIPCORD and the French Registry.

Yet, despite the seemingly persuasive data summarised here, the uptake of PW at the diagnostic stage of the patient pathway is still low. There are, as yet, no suitably powered randomised trials using the PW systematically at the stage of diagnostic angiography and comparing outcome with management based upon angiography alone. This is the gap that will be filled by RIPCORD2.

RIPCORD2 will use the new Boston Scientific Pressure Wire (BSPW), which is currently undergoing first-in-man testing in Chile. The device has, of course, already been internally validated by Boston Scientific engineers and scientists, but the purpose of the COMET study is to provide independent and objective validation of the performance of BSPW using the performance of the St Jude Medical pressure wire (SJPW) as the reference, both using inter-wire and intra-wire measurements. Thus, not only will we assess the reproducibility of the measurements between the 2 wires, but the investigators will also compare reproducibility of measurements from 2 wires of the same manufacturer.

Inclusion criteria

• >18yrs age
• Written informed consent
• Patients scheduled for diagnostic angiography (and/or "standby" angiography)
• Clinical requirement for pressure wire assessment

Exclusion criteria

• STEMI presentation
• Aorto-ostial disease
• Pregnancy
• CABG
• Contraindication to adenosine
• Creatinine >180umol/L
• Life threatening co-morbidity
• Severe valve disease