New research reveals microvascular dysfunction of the heart

New studies show small vascular abnormalities in the human heart well beyond the aorta, with atherosclerotic obstruction that results in the need for stenting and bypass grafting. The findings may lead to the development of new treatments for patients with symptoms such as unobstructed angina, or for patients who have recovered from a heart attack or unexplained heart failure.

The normal intrinsic stenosis of these micro-arteries in response to changes in blood pressure is called myogenic (automatic) tension. Myogenic tone controls the distribution of blood flow in the heart muscle and elsewhere in the human body.

Current heart scans can identify large occlusions of the coronary arteries, but fail to show these small micro-arteries the size of a hair in patients, and muscles that would grow independently of significant arterial disease. It is not possible to diagnose a decrease in the primary voltage. In this study, tissue biopsies were used to investigate the function, structure, and changes of microarterial pathways associated with abnormal myogenic tone.

The BHF-funded study, led by Professor Raimondo Ascione of the University of Bristol (Clinical Manager) and Professor Kim Dora of the University of Oxford (Head of Basic Sciences), Cardiovascular research..

The research team took small heart samples that would otherwise be rejected from 88 patients who did not have a major coronary artery occlusion and who underwent surgery for valvular heart disease at the Bristol Heart Institute. In addition, heart samples were obtained from three organ donors from the Newcastle Transplantation Tissue Biobank and from 45 pigs treated at the Translational Biomedical Research Center (TBRC) at the University of Bristol.

The researchers found that 44% of patients’ micro-arteries have abnormal myogenic tone, even though they maintain cell viability. This abnormality is due to the excessive presence of molecules called caldesmon in the muscle cells of the wall of the abnormal micro-arteries, and these cells contracted compared to the micro-arteries with normal myogenic tone in the other 66% of the patients. It was linked to the improper alignment of the cells. , And all organ donors and pigs.

Microarterial abnormalities affect the beating blood supply to the heart and other organs in the body, affecting the quality of life and life expectancy of people.

The findings provide new insight into coronary microvascular dysfunction that may precede the development of clinically known heart diseases such as heart failure.

Professor Raimondo Ascione, NHS consultant cardiac surgeon and head of TBRC at the University of Bristol, said: Myogenic tension in previous cardiac microcirculation. These small arteries are located deep in the heart wall and well beyond occluded arteries treated with stenting or bypass surgery with the NHS and are not visible to the naked eye.

“Our study sheds light on microvascular dysfunction of the heart. A new way to help patients with symptoms like angina without coronary artery occlusion, or who are recovering from coronary artery occlusion. This can help in the development of treatments. heart attack Or heart failure of unknown cause. “

Kim Dora, professor of microvascular pharmacology at the University of Oxford, explains: A new modality for imaging patients, it represents a new model of ex-vivo research for thousands of scientists working on microvascular dysfunction around the world of the heart and other organs. “

Professor Jeremy Pearson, Associate Medical Director of the British Heart Foundation, said: Apply them to the micro-arteries of the human heart. The results provide new information to help develop treatments for many patients who develop angina without significantly narrowing the coronary arteries. ”

Currently, thousands of patients, mostly postmenopausal women, suffer from angina despite a coronary angiogram that does not show obvious occlusion of the large epicardial arteries of the heart, which are usually treated with stents or bypass grafts. New areas of research confirm that they exhibit such symptoms. Other patients seem to develop heart failure associated with contraction or relaxation of the heart for no apparent reason.

The human coronary arteries studied in the laboratory by the Bristol and Oxford team are human organs (lungs, lungs, heartWhere COVID-19 has caused most of the problems during an ongoing pandemic.