Syntax to expand graph hierarchy of SNOMED, including or excluding specific SCTIDs (although I’ve always thought that having to specifically exclude some terms defeats the utility of the inheritance/parent-child feature of SNOMED)"
In reality, once you get out of things like substance and diagnosis, the hierarchies in SCT get very messy and potentially risky, if your selections trigger some kind of CDSS. You also have no control over what is being added to the codeSystem -the additions may not be wrong ontologically but can cause major clinical safety/application issues.
FHIR Valuesets do support some limited ‘subsumption’ etc but I tend to avoid in application building unless it is true
broad refset underneath like ‘any diagnosis’
Our experience in that you almost always want to lock these things down at deployment level.