Structural features of the coronary sinus in human fetal heart: a pilot study

Objective - to provide anatomical features of the coronary sinus (CS) in the human fetal heart.

Materials and methods. We examined 43 heart specimens using an Olympus SZX2-ZB10 stereomicroscope (magnification 4.725-45) to measure CS dimensions, analyze its valve, and assess intimal surface morphology. We studied the microscopic anatomy of the CS walls using hematoxylin-eosin, Masson trichrome, van Gieson staining, and scanning electron microscopy.

Results. The CS originated at the midpoint between the left pulmonary surface and the cardiac "crux". Its length increased from 6.26 mm (16-22 weeks) to 12.63 mm (23-36 weeks), showing a strong correlation with ventricular complex length (Rs=0.88; p<0.05). In 70% of cases, we observed that CS width expanded along the blood flow direction, reaching 1.84 mm (16-22 weeks) and 2.62 mm (23-36 weeks) near the "crux". At the transition from the great cardiac vein to the CS, we consistently identified an ostial valve, formed by a fold and/or ridge. We detected a valve at the CS orifice in 19 out of 20 specimens. The CS received 2 to 6 tributaries (median: 4), including 2-3 inferior left ventricular veins and 1-2 posterior left atrial veins. The middle cardiac vein, the largest tributary, appeared as a single vessel in all cases. A myocardial "sleeve" surrounded the CS, defining its wall thickness and typically displaying two muscle layers: longitudinal and circular. Some specimens showed intimal folds aligned with blood flow.

Conclusion. The study showed that the human fetal coronary sinus exhibits both consistent anatomical features and individual variations in size, valve structure, and wall histotopography.

1. Anderson R.H., Cook A.C., Spicer D.E., Hlavacek A.M., Backer C.L., Tretter J. Surgical anatomy of the coronary circulation. In: Wilcox's surgical anatomy of the heart, 2024:113-132. DOI: 10.1017/9781009387408.006

2. Korobkeyev A.A., Nikolenko V.N., Lezhnina O.YU., Astakhova O.N., Neyzhmak N.V., Galeysya E.N. Morphofunctional organization of the venous bed of the subepicardial bed of the human heart in the age aspect. Stavropol′: Stavropol′skiy gosudarstvennyy meditsinskiy universitet, 2012. 176 p. (in Russ.). EDN: QBLPSX.

3. Loukas M., Bilinsky S., Bilinsky E., el-Sedfy A., Anderson R.H. Cardiac veins: a review of the literature. Clin Anat. 2009;22(1):129-145. DOI: 10.1002/ca.20745

4. Mlynarski R., Mlynarska A., Sosnowski M. Anatomical variants of coronary venous system on cardiac computed tomography. Circ J. 2011;75(3):613-618. DOI: 10.1253/circj.cj-10-0736

5. Kassem M.W., Lake S., Roberts W., Salandy S., Loukas M. Cardiac veins, an anatomical review. Translat Res Anatomy. 2021;23:100096. DOI: 10.1016/j.tria.2020.100096

6. Kafarov E.S., Miltykh I.S., Zenin O.K. Cardiac venous system: a literature review. Medical News of North Caucasus. 2023;18(4):417-423. (in Russ.). DOI: 10.14300/mnnc.2023.18100. EDN: OSRTHA.

7. Naito M., Yu H.C., Kim J.H., Rodríguez-Vázquez J.F., Murakami G., Cho B.H. Topographic anatomy of the fetal inferior vena cava, coronary sinus, and pulmonary veins: Variations in Chiari's network. Clin Anat. 2015;28(5):627-637. DOI: 10.1002/ca.22489

8. Mikhalkina M.V. Analysis of morpho-functional parameters of the subepicardial veins of the human heart in the intermediate fetal period. Ural Medical Journal. 2018;4(159):10-12. (in Russ.). DOI: 10.25694/URMJ.2018.04.061. EDN: XSLQUX.

9. Kim J.H., Chai O.H., Song C.H., Jin Z.W., Murakami G., Abe H. Observations of foetal heart veins draining directly into the left and right atria. Folia Morphol (Warsz). 2019;78(2):283-289. DOI: 10.5603/FM.a2018.0077

10. Nemirova S.V., Kosonogov A.Ya., Shakhov E.B., Nikolsky A.V., Kosonogov K.A., Zheleznov A.B., Zhekhov O.N., Kurnikova A.A. Variants of structure of cardiac coronary sinus. Meditsinskiy Al′manakh. 2016;4(44):79-83. (in Russ.). EDN: WQRMBV

11. Żabówka A., Hołda J., Strona M., Koziej M., Krawczyk-Ożóg A., Jasińska K.A., Kuniewicz M., Lelakowski J., et al. Morphology of the Vieussens valve and its imaging in cardiac multislice computed tomography. J Cardiovasc Electrophysiol. 2019;30(8):1325-1329. DOI: 10.1111/jce.14018

12. Sirajuddin A., Chen M.Y., White C.S., Arai A.E. Coronary venous anatomy and anomalies. J Cardiovasc Comput Tomogr. 2020;14(1):80-86. DOI: 10.1016/j.jcct.2019.08.006

13. Sławek-Szmyt S., Szmyt K., Żaba C, Grygier M., Lesiak M., Araszkiewicz A. Peculiarities in coronary sinus anatomy: implications for successful cannulation from an autoptic study. Europace. 2021;23(11): 1787-1794. DOI: 10.1093/europace/euab108.

14. Picazo-Angelin B., Zabala-Argüelles J.I., Anderson R.H., Sánchez-Quintana D. Anatomy of the normal fetal heart: The basis for understanding fetal echocardiography. Ann Pediatr Cardiol. 2018;11(2): 164-173. DOI: 10.4103/apc.APC_152_17

15. Kagan I.I., Belyanin V.V., Demin A.V. Roentgenoanatomical differences of heart coronary sinus on data of intravital coronary angiography. Morphological Newsletter. 2011;(3):39-43. (in Russ.). EDN: PZBODV.

16. Dmitrieva E.G., Gaponov A.A., Iakimov A.A., Khatsko S.L. The coronary sinus and adjacent structures in human adult hearts: Morphometrical cadaveric anatomy. European Journal of Anatomy. 2022;26(1):3-17. DOI: 10.52083/BNUM8219

17. Spicer D.E., Anderson R.H. Normal cardiac anatomy. In: Abdulla Ri., et al. (eds.) Pediatric Cardiology. Springer, Cham. 2023. DOI: 10.1007/978-3-030-42937-9_103-1

18. Bokeriya L.A., Revishvili A.Sh., Serov R.A., Basarab Yu.S., Davtyan K.V., Melikulov A.Kh., Shmul′ A.V. Topographic and anatomical features of the coronary sinus of the heart. The Bulletin of Bakoulev Center Cardiovascular Diseases. 2007;8(6):32-40. (in Russ.). EDN: JZGQZD.

19. Echeverri D., Cabrales J., Jimenez A. Myocardial venous drainage: from anatomy to clinical use. J Invasive Cardiol. 2013;25(2):98-105.

20. Hołda M.K., Klimek-Piotrowska W., Koziej M., Mazur M. Anatomical variations of the coronary sinus valve (Thebesian valve): implications for electrocardiological procedures. Europace. 2015;17(6): 921-927. DOI: 10.1093/europace/euu397.

21. Harsh Kumar Chawre, Vishal Bhadkaria, Joshi S.D., Joshi S.S. Gross and histological study of coronary sinus and its clinical relevance. Journal of Evolution of Medical and Dental Sciences. 2015;4(101): 16655-16661. DOI: 10.14260/jemds/2015/2486

22. Hikspoors J.P.J.M., Anderson R.H., Lamers W.H., Mohun T.J. Normal development of the heart. In: Pediatric Cardiology. R. Abdulla et al. (eds.). Springer Nature Switzerland AG. 2023. DOI: 10.1007/978-3-030-42937-9_8-1.

23. Anderson R.H., Kerwin J., Lamers W.H., Hikspoors J.P.J.M., Mohun T.J., Chaudhry B., Lisgo S., Henderson D.J. Cardiac development demystified by use of the HDBR atlas. J Anat. 2024;245(4):517-534. DOI: 10.1111/joa.14066.

24. Kosourov A.K., Ivanov V.A. Structural features of the heart coronary sinus in adult humans. Morfologiia. 2005;128(6):33-37. (in Russ.). DOI: 10.34922/AE.2020.158.4.006. EDN: RGILDN.