Correlations of myocardial bridges with left ventricle myocardial hypertrophy and prepontin coronary atherosclerosis

Background: Of particular interest are the studies researching the correlations of myocardial bridges with hypertrophic cardiomyopathy and correlations of thick myocardial bridges with the development of coronary atherosclerosis in the proximal to the bridge arterial part. Material and methods: Assessment of the correlation between myocardial bridges, coronary atherosclerosis, and the degree of hypertrophy of the left ventricle was performed by retrospective analysis of 6168 coronary angiography protocols (2012-2019) and echocardiographic data from patients’ clinical records. Results: Moderate systolic compression predominated, and the number of patients detected with severe under the bridge systolic coronary stenosis was double as in patients with nonsignificant coronary atherosclerosis. From the total number, patients with myocardial hypertrophy and myocardial bridges were twice less when compared with the patients with the normal myocardial thickness. The comparative research did not show any interdependence between the degree of vascular compression and the degree of left ventricular myocardial hypertrophy. Proximal to the bridges atherosclerosis was detected in 32% of cases without correlation with the force of the myocardial bridge. Conclusions: The study showed the absence of the correlation between the degree of arterial stenosis caused by the bridge and the degree of hypertrophy of the ventricular myocardium as well as the degree of proximal to the bridge atherosclerosis. Important finding was that the degree of coronary systolic compression is higher in patients with moderate and severe proximal to the bridge atherosclerosis.

Characteristics of Human Myocardial Bridges in Health and in Coronary Atherosclerosis

This paper studies the characteristics of the myocardial bridges and the anterior interventricular artery in people aged 22–75 years using a histological method. Histological sections were made from three segments of the artery: proximal to the bridge, intramural and distal to the bridge. We found no differences in thickness of myocardial bridges, cross-sectional area of the perivascular space, as well as ratio of the cross-sectional areas of the perivascular space and intramural segment between the groups of hearts with coronary atherosclerosis (n = 7) and without it (n = 7). In subjects with coronary atherosclerosis, the cross-sectional area of the artery wall in the segment proximal to the bridge was larger than that in the group without atherosclerosis due to increased intima thickness. However, no changes in the lumen of the artery were observed. For citation: Dmitrieva E.G. Characteristics of Human Myocardial Bridges in Health and in Coronary Atherosclerosis. Journal of Medical and Biological Research, 2021, vol. 9, no. 4, pp. 454–458. DOI: 10.37482/2687-1491-Z083

Angioarchitecture of the coronary arteries in Mazama gouazoubira (G. Fischer, 1814)

Mazama gouazoubira is a widely distributed deer in the South American continent. However, studies on its anatomical characteristics are still scarce. The objective of this study was to elucidate the coronary circulation of M. gouazoubira. With this aim, after collecting cadavers on highways, twenty-four hearts injected with latex and preserved in formaldehyde at 10% were dissected. The dissections revealed that all specimens presented left coronary dominance, characterized by the origin of the subsinuous interventricular branch from the circumflex branch of the left coronary artery. The number of ventricular branches originated from branches of the left coronary artery was approximately five times higher than that of the right coronary artery. The occurrence of myocardial bridges was registered in 91.7% of the individuals, with bridges predominating over the paraconal interventricular branch. The mean length of the paraconal interventricular sulcus was significantly higher in males (p = 0.02). The number of atrial branches and ventricular branches, length of myocardial bridges and length of subsinuous interventricular sulcus did not vary significantly between sex. Left coronary dominance and high frequency of myocardial bridges in M. gouazoubira are preponderant anatomical traits also present in different species of Ruminantia suborder. Coronary dominance studies in other South American deer species may confirm the correlation of this trait with the evolutionary history of these animals.

Comparative Study of Coronary Artery Proximal to Myocardial Bridge Segment

Introduction: The muscular segments which overlie the epicardial arteries are termed as myocardial bridges and the artery which travels through them are termed as tunnel arteries. These tunnel arteries get compressed during the systolic compression of the heart, thus partially or completely blocking the blood supply to the corresponding areas. Aim & Objectives: To assess the impact of these myocardial bridges on the proximal segment of the myocardial arteries. Methodology: The present study was cadaveric-based cross-sectional study. A total of 22 hearts which showed the presence of myocardial bridges were collected from two sources namely: cadaver dissections, autopsy. The hearts were clean and numbered. This was followed by fixation, dehydration, clearing, embedding, block formation, section cutting and staining. Result: The present study showed that there is a significant thickening in the tunica intima of the proximal to bridge segment of the coronary artery. The present study also noted that there is a marked thinning of the tunica media of the same segment. Conclusion: The present study concludes that there is a marked hyperplasia in the proximal segment of the myocardial bridges under tunica intima.

Myocardial bridges and coronary distribution in dairy cattle from Brazil Northeast

This study evaluated the distribution and possible variations of the coronary arteries and the presence of myocardial bridges in dairy cattle from Northeastern Brazil. Thus, healthy hearts were analyzed according to many variables. Left coronary artery originate the rami paraconalis, circumflexus et subsinuosus. Ramus subsinuosus and right coronary artery showed a short subepicardial path. Lengths of the main branches showed statistical differences only in relation to age group and weight of the animal. Myocardial bridges had a prevalence of 55% and were more frequent over the ramus paraconalis. Veterinary medicine is able to provide experimental models to expand the necessary study to understand pathophysiology and clinical relevance of the bridges.

Immediate results of treatment of patients with myocardial bridges of the coronary arteries

The objective was to evaluate the immediate results of treatment of patients with symptomatic form of myocardial bridges of the coronary arteries.Methods and materials. In the course of a retrospective study, the results of treatment of 70 patients who had underwent drug treatment and 52 patients who had underwent surgical treatment were analyzed. All the subjects had high functional angina pectoris.Results. Pharmacological therapy showed significant positive dynamics in 18 (25.7 %) patients. Analysis of the intraoperative and early postoperative periods in patients who underwent supracoronary myotomy allows us to conclude that surgical treatment of patients with myocardial bridges of the coronary arteries shows satisfactory results.Conclusion. Drug therapy may be effective in some patients with myocardial bridges of the coronary arteries. In case of ineffectiveness of pharmacological treatment, the possibility of performing surgery in the amount of supracoronary myotomy should be considered.

Echocardiographic changes and quality of life after surgical unroofing of myocardial bridges

Objective To examine the echocardiographic changes and quality of life (QoL) after surgical unroofing of myocardial bridges (MBs) involving the left anterior descending (LAD) coronary artery compared with optimal medical therapy (OMT). Methods Twenty-two patients (median age, 24 years; interquartile range, 16–40 years) with MBs of the LAD artery and exertional angina from 2018 to 2019 were retrospectively analyzed. Twelve patients underwent OMT and 10 underwent surgery. Both groups underwent clinical and echocardiographic examinations during hospitalization and follow-up (mean, 1.0 ± 0.8 years). QoL was assessed with the Seattle Angina Questionnaire, short version (SAQ-7). Results Surgery resulted in significantly better QoL than OMT, with a significant improvement in left ventricular global longitudinal strain (GLS) [mean (standard error): 19% (0.19) to 22% (0.34) and 19% (0.15) to 20% (0.24), respectively; delta-change (delta-GLS) of 0.15 vs. 0.067]. In the univariate and multivariable analyses, delta-GLS was positively correlated with the SAQ-7 score and MB length (rho = 0.64 and 0.71, respectively), with a significant interaction between MB length and surgical treatment (beta coefficient, 1.95; 95% confidence interval, 0.14–3.77). Conclusions MB unroofing surgery provided benefits in terms of QoL and left ventricular GLS improvement compared with 1 year of OMT.

Some morphological aspects of myocardial bridges

Background: Myocardial bridges are variants of the intramyocardial position of the coronary arteries. In the specialty literature, hot topics in cardiovascular field are myocardial infarction and non-obstructive coronary artery disease with frequent connection with myocardial bridges. Material and methods: The morphological study was based on the analysis of 200 human hearts and fragments of coronary arteries. The retrospective study was focused on the analysis of 6168 coronary angiography reports, to identify patients with myocardial bridges, their preferred location, the degree of systolic stenosis, the association between myocardial bridges and proximal to bridge and under the bridge coronary atherosclerosis. Results: The complete myocardial bridges were described in 62% of the analyzed hearts and only in 5.3% of the total number of studied coronarographies. In the majority of cases, the complete myocardial bridges covered the anterior interventricular branch. The degree of subpontine arterial systolic stenosis varied within 10-95%. The comparative study did not determine any correlations between the degree of subpontine vascular compression and the degree of the left ventricular myocardial hypertrophy. In 32% of cases were described proximal to bridge atherosclerotic plaques and only in one case (0.5%) – distal to bridge atherosclerotic plaques, located immediately under the bridge. Conclusions: The research findings underline the differences in anatomical and angiographic incidence of myocardial bridges, and the inability of all bridges to reduce the lumen of under bridged artery. Current study emphasizes attention to the topography of bridges, the correlation with ventricular hypertrophy and coronary atherosclerosis.