Could hourglass stents be used to help patients who suffer from chest pain (angina) caused by Ischaemia with Normal Coronary Arteries (INOCA)? That’s the question researchers hope to answer, thanks to funding from the British Heart Foundation (BHF).
With the help of his team, Dr Ranil De Silva, consultant cardiologist at Royal Brompton and Harefield hospitals and senior lecturer in clinical cardiology at Imperial College London, will be testing the new stent in a subgroup of patients who suffer from INOCA.
Patients with INOCA experience angina caused by restricted blood flow to the heart muscle. However, unlike with coronary artery disease (CAD), the coronary arteries on the surface of the heart are normal. In these patients, reduced blood supply to the heart muscle is thought to be caused by abnormal function of the small blood vessels which are embedded within the heart muscle, which play a central role in control of blood flow to the heart. This is termed coronary microvascular dysfunction.
Studies have shown that patients with INOCA and coronary microvascular dysfunction have an increased risk of poor health outcomes and hospital admissions, as well as poor quality of life.
Current treatment options for patients with INOCA and coronary microvascular dysfunction are limited. While guidelines recommend a variety of drug treatments, there are few robust clinical trials to underpin these recommendations. Crucially, there are no procedure-based treatments available to help improve blood flow to the heart and reduce symptoms in this patient group.
The research team, with support from the BHF, aim to run the REMEDY-PILOT study to evaluate whether placing an hourglass-shaped stainless steel stent, known as a Reducer, placed into the coronary sinus (the main vein of the heart) is an acceptable intervention for patients, and will improve blood flow in the hearts of those patients with angina and INOCA.
Dr De Silva and his team believe that by narrowing the coronary sinus, the Reducer will help redistribute blood flow to those areas of the heart with restricted blood flow, thereby reducing their symptoms of chest pain.
Dr De Silva says;
“There are huge numbers of patients with chest pain who have no evidence of conventional coronary artery disease, but whose chest pain can still be caused by reduced blood flow to the heart. The diagnosis is frequently not made, and their treatment options are very limited. This is a very important opportunity for us to evaluate rigorously if and how Reducer implantation may help patients within this group.
“This is a crucial first step towards developing the first interventional treatment for patients with INOCA and coronary microvascular dysfunction, which has the potential to transform care for these patients. We are extremely grateful to the BHF for recognising the importance of supporting research to address the unmet clinical needs of this patient group.”
If successful, the REMEDY-PILOT study will provide the basis for a future multi-centre clinical trial of Reducer implantation in patients with INOCA and coronary microvascular dysfunction, which will definitively answer the question of whether Reducer implantation improves angina symptoms and quality of life in patients with INOCA and coronary microvascular dysfunction.
The trial is expected to start in October 2021.
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