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International Society for the
Study of Vascular Anomalies


Please Click Here to review the 2018 Classification. The updated classification was approved at the May, 2018 General Assembly in Amsterdam, the Netherlands.

For citations please use: ISSVA Classification of Vascular Anomalies ©2018 International Society for the Study of Vascular Anomalies Available at "" Accessed [date]

Creative Commons

ISSVA classification for Vascular Anomalies by International Society for the Study of Vascular Anomalies is licensed under a Creative Commons Attribution 4.0 International License.

ISSVA Ontology

What is ISSVA Ontology?

The ISSVA ontology has been created to represent a sharable semantic data model of the ISSVA classification. This ontological representation of the ISSVA classification is machine-readable and facilitates interoperability between systems that capture data about vascular anomalies. It is structured hierarchically and contains all concepts of the ISSVA classification and the relationships between them. The ontology is available in the Web Ontology Language (OWL) format, and can be browsed and downloaded online:

How to Use the ISSVA Ontology?

The ISSVA ontology does not substitute the ISSVA classification, instead, it should be used as an additional component to facilitate interoperability. Every concept in the ISSVA ontology has a unique code that should be attached to the corresponding data element. In the context of databases, the ISSVA ontology codes could be added as an extra column to the existing data. 

Mappings to Other Ontologies?

The ISSVA ontology contains machine-readable mappings to equivalent concepts in other ontologies, namely: the Orphanet Rare Disease Ontology (ORDO), SNOMED Clinical Terms (SNOMED CT), National Cancer Institute thesaurus (NCIT), and the Human Phenotype Ontology (HPO). This means that data annotated with codes from the ISSVA ontology are interoperable with data annotated with the aforementioned ontologies, without any extra effort, as long as there exists a mapping between the concepts.

Issue Reporting

Please contact ISSVA at in case you have any issues and/or feature requests for the ISSVA ontology. The ontology can then be updated accordingly.