Extravasal compression of distal coronary arteries in immobilizing interstitial fibrosis of the heart – Shevchenko-Brado angiographic symptom complex

Heart failure is usually based on damage to cardiomyocytes. At the same time, the most common cause of myocardial dysfunction is coronary heart disease (CHD), various inflammatory processes, excessive physical overload, including acquired and congenital heart defects, and so on. However, it is not uncommon to meet patients with heart failure, in whom the listed causes are absent and are not confirmed by either instrumental or laboratory studies, and the treatment of such patients is ineffective. Long-term clinical practice, numerous scientific and experimental studies by Academician of the Russian Academy of Sciences Shevchenko Y.L. allowed us to establish that the cause of such myocardial dysfunction is immobilizing interstitial fibrosis of the heart. which is based on direct compression of cardiomyocytes (immobilization) by sharply compacted connective tissue (diploma for discovery No. 536 dated August 23, 2023). Immobilizing interstitial fibrosis of the heart, which occurs as a result of excessive deposition of physically altered collagen fibers and structural and functional transformations of the myocardium, can be primary or secondary (induced) and occurs in many chronic cardiac diseases, including coronary heart disease. The available data indicate that an increase in the number of collagen fibers, metamorphoses of their composition and physico-chemical properties play a leading role in impaired microcirculation, extravasal compression of coronary arteries, remodeling of the left ventricle and a decrease in heart contractility, which may explain the unsatisfactory results of treatment of various groups of patients with heart failure, including patients after coronary bypass surgery. The results of the study indicate a fairly frequent detection of interstitial immobilizing fibrosis in patients with coronary heart disease with a reduced left ventricular ejection fraction. The recognition of immobilizing interstitial fibrosis of the heart presents serious difficulties. However, a comprehensive assessment of general clinical, instrumental and laboratory studies makes it possible to diagnose this insidious disease with greater certainty, the most severe stage of which is determined by compression of the peripheral coronary arteries (coronary stage). The article describes the main pathophysiological mechanisms of the formation of immobilizing interstitial fibrosis of the heart and the most important angiographic signs of its most severe stage of extravasal compression of the coronary arteries – the Shevchenko-Brado symptom complex. Materials and methods The prospective study included the results of observations of 82 patients who were treated at the St. George Thoracic and Cardiovascular Surgery Clinic of the Federal State Budgetary Institution "NMHC named after N.I. Pirogov" of the Ministry of Health of the Russian Federation from 2020 to 2024. Group I (n=33) – patients with coronary heart disease and immobilizing interstitial fibrosis (IFS). Group II (n=40) – patients with coronary heart disease without IFS. To assess the manifestations of the Shevchenko-Brado angiographic symptom complex, an additional group of patients was considered separately – group III (n=9) with a coronary stage of primary IFS without coronary artery disease. The average age of patients was 63.26±5.7 years (group I), 64.9±6.6 years (group II), 55.9±5.9 years (group III). Clinical data, magnetic resonance imaging, echocardiography were evaluated. Selective coronary angiography was performed at a frequency of 15 frames per second. Myocardial biopsy, histological examination of biopsies were performed, the percentage of fibrosis sites to the total area of the tissue fragment under study, the volume of collagen fibers of types I and III were calculated. Results According to clinical, morphological and instrumental data, five stages of IFS have been identified. In all patients with primary IFS without coronary artery disease (group III), the Shevchenko-Brado symptom complex was detected, the duration of the passage of contrast agent from the trunk of the left coronary artery to the coronary sinus was 6.4 [5.8; 6.9] seconds. This symptom complex is specific for the coronary stage of IFS, however, it can manifest itself in different ways in its other forms: in the group I the angiographic picture of diffuse thinning of the distal sections of the coronary arteries by the type of "mouse tails" was determined in 63.64% (n=21), in the group II - 22.5% (n=9), OR 6.03 (95% CI 2.16-16.83) p=0.0004. When comparing these observations with histological examination data, it turned out that in cases of severe and extremely severe stage of immobilizing IFS, extravasal compression of the coronary arteries was detected. Statistically significant differences were found in the studied groups: lengthening of the time of "native" T1, according to MRI data: 1128.0 [1059;1181] ms (group I), 952.0[914;993] ms (group II) p<0.0001, an increase in the volume of intercellular space: 39.0[34;50]% (group I), 24,5[21;28]% (group II), at p<0.0001. According to a special histological study, the average area of fibrosis zones in the group I was 18.7[11;27]%, type I collagen – 4795[3992;6157] per 1 mm2 and type III collagen – 3531[2350;4905] per 1 mm2. Conclusion The formation of interstitial immobilizing fibrosis is almost always an integral part of the pathological process of heart remodeling. There are specific signs of IFS that can help in diagnosis, including the described angiographic Shevchenko-Brado symptom complex, which is detected in patients with severe immobilization of the peripheral coronary bed.