After being informed about the study and the potential risks and benefits, participants who provide written consent will be screened to make sure they fulfil the study entry requirements. They will undergo screening assessment and if they don't meet any exclusion factors and found to be eligible they will be randomised to one of two groups and start preparation for the investigational or sham bone marrow aspiration and infusion procedure.~Once enrolled they will undergo baseline assessments such as the quality of life and angina questionnaires, ECG, physical measurements such as height, weight, blood pressure, some blood tests, perfusion imaging and exercise testing.~All participants will be blinded to their procedure. They will wear a blindfold and noise cancelling headphones for the bone marrow aspiration and the infusion procedures.~For those randomised to the investigational procedure: Bone marrow aspiration is performed early morning on the day of the procedure and sent for processing and returned the same day ready for infusion. The participant is taken to the cath lab, a local anaesthetic and radial or femoral sheath is inserted. An angiogram is performed and suitable coronary arteries for stem cell infusion identified. 3.3mls of cells are infused over a 3 minute period after each balloon inflation. After 3 minutes, the balloon is deflated and flow and vessel checked with a diagnostic angiogram. This process can be repeated three times (with a 3 minute break each time the balloon is deflated) until all 10mls of cells have been infused. At the end of the procedure the patient returns to the ward for standard post percutaneous coronary intervention procedure observations.~The whole procedure should take about 30-45 minutes. For those randomised to the sham procedure: A sham bone marrow aspiration is performed early morning on the day of the procedure. Local anaesthetic is given and a 3mm skin incision is made. The procedure will take approximately the same time as bone marrow aspiration. Later the participant is taken to the cath lab, a local anaesthetic and radial or femoral sheath is inserted. Approximately 30 minutes later the sheath is removed and the patient returns to the ward for standard post percutaneous coronary intervention procedure observations.~Post-procedure all participants will be managed according to standard clinical practice and may be discharged home any time between 4 to 24 hrs post procedure. Further assessments are completed before they are discharged.~A follow up telephone call at 1 week is to assess for any complications of the procedure.~Follow up visits are again performed at 6 months and 1 year after the procedure. The following measurements such as an ECG, physical measurements (height, weight and blood pressure), some blood tests, quality of life and angina symptom questionnaires are completed at each visit. In addition, at the 6 month visit, an exercise test and a myocardial perfusion scan will be performed.~At all visits participants will be asked about any adverse events or hospital admissions that may have occurred.
The purpose of this randomised clinical trial is to see if infusing autologous stem cells into the coronary arteries is a safe and efficacious procedure and will improve the symptoms and quality of life in patients with refractory angina.