ORBITA-SOLAR
Research type
Research Study
Full title
ORBITA-SOLAR: Study of Lesion-Specific Invasive Haemodynamic Thresholds for Angina
IRAS ID
342508
Contact name
Rasha Al-Lamee
Contact email
Sponsor organisation
Imperial College London
Duration of Study in the UK
3 years, 0 months, 0 days
Research summary
Coronary artery stenoses are narrowings in the blood vessels supplying the heart muscle that can cause symptoms of angina. An angioplasty is a procedure that uses wires, balloons and stents, to open up the stenoses and relieve angina. During the procedure, specialised equipment called pressure wires are commonly used to measure the amount of blood flow reduction caused by a stenosis. A threshold of 20% reduction in blood flow is widely used to decide whether or not a stent is offered.
Current practice does not consider that the 'angina threshold', or amount of blood flow reduction required to cause symptoms, may differ between patients and even between individual stenoses. Assuming a universal angina threshold may mean that some patients are not being offered stenting when it could be beneficial, while others may receive stents when their stenoses are not the cause of their symptoms. This may be why 40-60% of patients continue to have symptoms despite successful stenting.
This study aims to find out whether different coronary artery stenoses have different angina thresholds. Patients with angina, 2 coronary artery stenoses, who have been referred for stents by their treating cardiologist, will be recruited. During the angioplasty procedure and after both stents have been placed, the angina threshold at the site of each stent will be measured. A small balloon will gradually be inflated within the coronary artery stent, while the patient performs exercise by pedalling on a bicycle. A pressure wire will be used to measure the precise reduction in blood flow caused by the balloon, that corresponds to symptom onset (i.e. the 'angina threshold').
The results of this study will improve our understanding of the relationship between stenoses, blood flow reduction and symptoms. This will enable future cardiologists to deliver more personalised and effective care for patients with angina.
REC name
London - West London & GTAC Research Ethics Committee
REC reference
26/LO/0038
Date of REC Opinion
4 Feb 2026
REC opinion
Further Information Favourable Opinion