Hahaha @mgkahn, yes, I certainly subscribe to using standards, and I recognize the consequences of that position. The legacy of using ICD9 codelists that were previously published as justification for future work is an inertia that we as a community will continue to have to push hard to overcome. My real question here is really more clinically motivated: if there are differences in types of cerebral infarctions (e.g. some are infarcts that are part of migraines, and some are infarcts that are full-blown strokes), then can or should we have a way to differentiate these types?
As a more specific illustration of the dilemma, I can currently select the descendants of 'cerebral infarction' and that finds me concepts with greater specificity (and in ICD9 world, the 'stroke-related infarctions' all map to these more specific concepts, so if all I cared about was replicating a ICD9-based publication, I can do it without issue). But it is possible that source data may have something that does not provide added specificity (e.g. in ICD10 world, there's a nonbillable code of I63, which is just 'cerebral infarction'), and depending on the circumstance, I may want these non-specific data to be included. Perhaps the answer is: 'all non-specific cerebral infarctions should to be considered equivalently', in which case the mapping question becomes: 'is the cerebral infarction listed in the migraine source codes REALLY a cerebral infarction?'