Disorders of endothelium-dependent vasodilation in patients with microvascular angina

Background: disorders of both endothelium-dependent and endothelium-independent vasodilation play a role in the pathogenesis of microvascular angina (MVA), the contribution of which may be different. Aim: to study the processes of endothelium-dependent vasodilation (EDV) in patients with primary MVA. Patients and Methods: an open prospective study included 60 patients (mean age 57.3±6.4 years) with MVA, confirmed clinical picture (chest pain), coronary angiography data (the absence of coronary artery stenosis), positive stress test (pain syndrome and/or ST segment depression by ≥2 mm by treadmill exercise stress test), positron emission tomography (PET) myocardial perfusion imaging (MPI) with tests (cold pressor test and with adenosine). Patients with diseases that can lead to secondary microvascular dysfunction were not included in the study. To evaluate the processes of EDV, all patients underwent the following evaluations: peripheral arterial tonometry (PAT), assessment of circulating endothelial cells (CEC), high-sensitivity C-reactive protein (hsCRP), endothelin-1 (ET-1), total antioxidant status. Adding that, the results of a cold pressor test during PET were analyzed. Results: the majority of the examined patients were women — 81.7%. Most of the female patients included in the study (93.9%) were postmenopausal. In all patients with MVA, according to the data of PET MPI with cold pressor test, signs of EDV disorder were detected as a decrease in coronary blood flow through the three coronary arteries. During PET, the index of reactive hyperemia was reduced (<1,67) in all examined patients and amounted to 1.43±0.15. According to the results of laboratory studies, there was an increase in the level of ET-1 and CEC — 3,335 [1,545; 3,952] fmol/L and 14±8 cells/3×105 leukocytes, respectively. The CRP level was 4,44 [1.02; 4.45] mg/L. The total antioxidant capacity was reduced in 53 (88%) patients, the average values of the indicator were 289,03±52,14 μmol/L. Conclusion: according to laboratory and instrumental studies, signs of endothelial dysfunction, namely disorders of EDV, were revealed in all examined patients with primary MVA. KEYWORDS: microvascular angina, peripheral arterial tonometry, endothelium-dependent vasodilation, positron emission tomography. FOR CITATION: Leonova I.A., Zakharova O.V., Boldueva S.A. Disorders of endothelium-dependent vasodilation in patients with microvascular angina. Russian Medical Inquiry. 2022;6(8):427–432 (in Russ.). DOI: 10.32364/2587-6821-2022-6-8-427-432.