Online first
Review article
Published online: 2024-09-02
The complete anatomy of the azygos vein: a meta-analysis with clinical implications
DOI: 10.5603/fm.101166
Pubmed: 39257193
Abstract
Background: The azygos vein (AV) plays a crucial role in the mediastinal region, exhibiting considerable variability in its anatomy and relationship with surrounding structures. This study aims to assess the morphometry and anatomy of the AV through a comprehensive meta-analysis of studies reporting extractable data on this vessel.
Materials and methods: Major online medical databases such as PubMed, Scopus, ScienceDirect, Web of Science, SciELO, BIOSIS, Current Content Connect, Korean Journal Database and Wiley online library were searched to gather all relevant studies regarding the anatomical characteristics of the AV.
Results: The results of the present meta-analysis comprised 40 studies, categorized into eight groups for data analysis. The mean AV diameter at its origin was set at 3.86 mm (SE = 0.84). The most prevalent was type IIB, with a prevalence of 40.23% (95% CI: 29.06–51.92%). The pooled prevalence of the right subcostal and right ascending lumbar veins forming the AV was 73.82% (95% CI: 55.77–88.67%).
Conclusions: The AV exhibits a high degree of variability regarding its origin, trajectory, and connections with the hemiazygos system. The most prevalent type of AV, according to the Anson and McVay classification, was Type II (transitional type). Moreover, the vein was found to be formed by the right subcostal and the right ascending lumbar veins in the majority of the cases. This is the most comprehensive and current assessment of AV morphometry and anatomy to date. The findings are a valuable resource for physicians, especially surgeons performing various procedures in the mediastinum.
Keywords: Azygos veinazygos venous systemanatomythoraxmediastinumsurgery
References
- Study of various patterns of azygos venous system and its clinical significance. IJFMT. 2021; 15(4): 9–13.
- Alves E, Junior WP, Bispo RM, et al. Formation of the azygos vein. Int J Morphol. 2011; 29(1): 140–143.
- Andreassi G. Osservazioni intorno alle origini delle vene grande azigos ed emiazigos nell’ uomo. Richerche di Morfol. 1931; 11: 309–327.
- Anson BJ, McVay CB. Surgical Anatomy. 6th ed. Saunders, Philadelphia 1984.
- Bogs T, Zwink N, Chonitzki V, et al. Esophageal Atresia with or without Tracheoesophageal Fistula (EA/TEF): Association of Different EA/TEF Subtypes with Specific Co-occurring Congenital Anomalies and Implications for Diagnostic Workup. Eur J Pediatr Surg. 2018; 28(2): 176–182.
- Celik HH, Sargon MF, Aldur MM, et al. An anomalous course of the interazygos vein. Surg Radiol Anat. 1996; 18(1): 61–62.
- Dahran N, Soames R. Anatomical variations of the azygos venous system: classification and clinical relevance. Int J Morphol. 2016; 34(3): 1128–1136.
- D'Antoni AV, Tubbs RS, Patti AC, et al. The critical appraisal tool for anatomical meta-analysis: a framework for critically appraising anatomical meta-analyses. Clin Anat. 2022; 35(3): 323–331.
- Diaconu CI, Staugaitis SM, Fox RJ, et al. A technical approach to dissecting and assessing cadaveric veins pertinent to chronic cerebrospinal venous insufficiency in multiple sclerosis. Neurol Res. 2012; 34(8): 810–818.
- Donohue JR, Daly DT. Anatomy, thorax, azygos veins. StatPearls, Treasure Island 2024.
- Endo J, Ichikawa T, Koizumi J, et al. Visualization of azygos arch valves using computed tomography: comparison of scanning delay times. Tokai J Exp Clin Med. 2008; 33(2): 84–89.
- Fukutome M. Vv. thoracica longitudinales observed in Japanese in Kyushu. Kumamoto Daigaku Igakubu Daini Kaibougaku Kyoshitsu Ronbun Shu. 1951; 2: 71–84.
- Hage R, Andrew K. Venous valves of the azygos arch: A cadaveric study. Transl Res Anat. 2024; 35: 100296.
- Henry BM, Vikse J, Pekala P, et al. Consensus guidelines for the uniform reporting of study ethics in anatomical research within the framework of the anatomical quality assurance (AQUA) checklist. Clin Anat. 2018; 31(4): 521–524.
- Higgins JPT, Thomas J, Chandler J. Cochrane Handbook for Systematic Reviews of Interventions. Wiley, Hoboken 2019: Wiley.
- Hovelacque A. Note sur les origines de la veine grande azygos et de l’h6mi-azygos inMrieure et sur leurs rapports avec le diaphragme. Bibliogr Anat. 1914; 24: 204–210.
- Ichikawa T, Endo J, Koizumi J, et al. Visualization of the azygos arch valves on multidetector-row computed tomography. Heart Vessels. 2008; 23(2): 118–123.
- Iwanaga J, Tubbs RS. Anatomical variations relevant to the lateral transpsoas approach to the lumbar spine. In: Tubbs RS, Iwanaga J, Oskouian RJ, Moisi M. ed. Surgical anatomy of the lateral transpsoas approach to the lumbar spine. Elsevier, Amsterdam 2020: 151–161.
- Kagami H, Sakai H. The problems in the arrangement of the azygos vein. Okajimas Folia Anat Jpn. 1990; 67(2-3): 111–114.
- Kanchana G. Study of the azygos system of veins in human cadaver. Raju Sugavasi Int J Cur Res Rev. 2013; 5(8): 113.
- Koutsouflianiotis K, Daniil G, Paraskevas G, et al. Computed tomography angiography study of the azygos vein course and termination into superior vena cava: gender and age impact. Surg Radiol Anat. 2021; 43(3): 353–361.
- Krakowiak-Sarnowska E, Wiśniewski M, Szpinda M, et al. Variability of the azygos vein system in human foetuses. Folia Morphol. 2003; 62(4): 427–430.
- Kreibich M, Siepe M, Grohmann J, et al. Aneurysms of the azygos vein. J Vasc Surg Venous Lymphat Disord. 2017; 5(4): 576–586.
- Kutoglu T, Turut M, Kocabiyik N, et al. Anatomical analysis of azygos vein system in human cadavers. Rom J Morphol Embryol. 2012; 53(4): 1051–1056.
- Maruthy P. An observational study on morphology of azygos vein. Indian J Clin Anat Physiol. 2020; 5(4): 497–500.
- Mohanty S, Panigrahi M, Upadhyaya J, et al. Variations in azygos venous system in the eastern indian population: a cadaveric study. Int J Anat Res. 2022; 10(4): 8505–8511.
- Moore KL, Dalley AF, Agur A. Clinically oriented anatomy 8th ed. Lippincott Williams and Wilkins, Philadeplhia 2017.
- Morita S, Suzuki K, Masukawa Ai, et al. Identification of efferent flow in the superior vena cava and azygos vein confluence using cine phase-contrast MRI: speculation of the role of the azygos arch valves. Magn Reson Imaging. 2010; 28(9): 1306–1310.
- Mustafa S, Ali T, Ahmed A. Anatomical variation of the azygos vein in human cadavers. Int J Innov Sci Res. 2016; 25: 368–372.
- Nathan H. Anatomical observations on the course of the azygos vein (vena azygos major). Thorax. 1960; 15(3): 229–232.
- Nirmala B, Rani S. Study of azygos system and its variations. J Evol Med Dent Sci. 2015; 4(33): 5652–5657.
- Gomes Md, Nobeschi L, Dias D, et al. Analysis of the territorial pattern of the azygos venous system and its variations in fixed cadavers. Transl Res Anat. 2020; 21: 100077.
- Parsons F, Robinson A. Eighth report of the committee of collective investigation of the Anatomical Society of Great Britain and Ireland, for the year 1897-1898. Question 111. The azygos veins. J Anat and Physiol. ; 1898: 197–203.
- Patra A, Singla R, Kaur H, et al. Analysis of multiple variations in azygos venous system anatomy with its classification: a cadaveric study. Eur J Anat. 2019; 23: 9–15.
- Piciucchi S, Barone D, Sanna S, et al. The azygos vein pathway: an overview from anatomical variations to pathological changes. Insights Imaging. 2014; 5(5): 619–628.
- Maruthy P. An observational study on morphology of azygos vein. Indian J Clin Anat Physiol. 2020; 5(4): 497–500.
- Priya A, Philip SE, Jain A, et al. Variations of azygos vein: a cadaveric study with clinical relevance. Anat Cell Biol. 2023; 56(4): 448–455.
- Pyrzowski J, Spodnik JH, Lewicka A, et al. A case of multiple abnormalities of the azygos venous system: a praeaortic interazygos vein. Folia Morphol. 2007; 66(4): 353–355.
- Radhika D, Vijaya Nirmala B, Kanchana Latha K. Tributaries of azygos vein. J Evid Based Med Healthc. 2016; 3(1): 49–51.
- Raghavendra A, Bhosale S. Variations of arch of azygos vein: an anatomical overview with clinical importance. Int J Anat Res. 2017; 5(3.2): 4251–4256.
- Rao K, Rani B, Ramagalla A, et al. A study of the azygos venous system and its variations. J Cardiovasc Dis Res. 2022; 13(5): 2424–2428.
- Rokutanda T. Comparative anatomical studies of azygos and hemiazygos vein in Japanese human embryo. Kumamoto Igakukaishi. 1959; 33(7): 2168–2175.
- Saito A, Murakami M, Tomioka K, et al. The impact of aging on the course of the azygos vein. Okajimas Folia Anat Jpn. 2015; 92(1): 7–10.
- Schröder W, Vallböhmer D, Bludau M, et al. The resection of the azygos vein--necessary or redundant extension of transthoracic esophagectomy? J Gastrointest Surg. 2008; 12(7): 1163–1167.
- Seib G. The azygos system of veins in American whites and American negroes, including observations on the inferior caval venous system. Am J Phys Anthropol. 2005; 19(1): 39–163.
- Shaw-Smith C. Oesophageal atresia, tracheo-oesophageal fistula, and the VACTERL association: review of genetics and epidemiology. J Med Genet. 2006; 43(7): 545–554.
- Shen XH, Su BY, Liu JJ, et al. A reappraisal of adult thoracic and abdominal surface anatomy via CT scan in Chinese population. Clin Anat. 2016; 29(2): 165–174.
- Singh S, Singh S, Prasad R. Observation on azygos system of veins in jharkhand population. IOSR J Dent Med Sci. 2019; 18(5): 29–37.
- Steinke K, Moghaddam A. Azygos arch valves at computed tomography angiography and pitfalls related to its variety in appearance and function. J Comput Assist Tomogr. 2009; 33(5): 721–724.
- Stelina F. A Study of Anatomical Variations In Azygos System Of Veins. Department of Anatomy Stanley Medical College Chennai. 2016.
- Tatar I, Denk CC, Celik HH, et al. Anatomy of the azygos vein examined by computerized tomography imaging. Saudi Med J. 2008; 29(11): 1585–1588.
- Tateshi S. Ober die Typen der V. azygos und V, hemiazygos. Nagasaki lgaku Zasshi. 1939; 17: 2448–2455.
- Tokutome M. Kyushu nihonjin ni okeru jukyojomyaku ni tsuite. umamoto Daigaku Igakubu Daini Kaibogaku Kyoshitsu Ronbun Shu. 1951; 3: 71–84.
- Tomaszewski KA, Henry BM, Kumar Ramakrishnan P, et al. Development of the Anatomical Quality Assurance (AQUA) checklist: Guidelines for reporting original anatomical studies. Clin Anat. 2017; 30(1): 14–20.
- Tori G, Garusi GF. The azygos vein arch and its valvular apparatus. Angiographic observations. Am J Roentgenol Radium Ther Nucl Med. 1962; 87: 235–247.
- Vedapriya K, Priyanka D. Morphological Variation in Azygos Vein. Int J Sci Res. 2018; 8(4): 1396–1399.
- Wang C, Zheng J, Ma X. Azygos vein preservation is feasible and beneficial in esophageal atresia with tracheoesophageal fistula: A meta-analysis of randomized controlled trials. Front Pediatr. 2022; 10: 965275.
- Wysiadecki G, Varga I, Klejbor I, et al. Reporting anatomical variations: Should unified standards and protocol (checklist) for anatomical studies and case reports be established? Transl Res Anat. 2024; 35: 100284.
- Yeh BM, Coakley FV, Sanchez HC, et al. Azygos arch valves: prevalence and appearance at contrast-enhanced CT. Radiology. 2004; 230(1): 111–115.
- Zumstein J. Zur Anatomie und Entwicklung des Venens&ems des Menschen. I. Ueber die Beziehungen der Vena cava inferior und ihrer Aeste zu der Vena azygos und hemiazpgos beim Neugeborenen und beim Erwachsenen. Anat Hefte, I Abt. 1896; 6: 571–608.
