In the process of validating CMS996v4 Appropriate Treatment for STEMI (eCQM) we have an identified an encounter where the patient had a primary dx of stroke, (I63.032 -Cerebral infarction due to thrombosis of left carotid artery)  with secondary dx of STEMI. It is unusual for us to transfer any STEMI patients from the ED, however, this patient had an occlusive stroke requiring immediate care at another facility. There is a denominator exclusion in the measure:"ISCHEMIC STROKE" for Active Exclusion Diagnosis Within 90 Days Before or At the Start of ED Encounter Encounter, however, this patient was not excluded.

We did look at the list of ICD Dx codes for Ischemic Stroke and noticed that I63.032 is not included. Can you explain why the value set does not contain the code for I63.032 Cerebral infarction due to thrombosis of left carotid artery since the description for the "valid" codes states "This grouping of value sets identifies patients who have had a stroke caused by ischemia, where the blood supply is restricted to an area of the brain by something like thrombosis or an embolism".

Interestingly enough, the value set does contain the ICD 10 Dx of I63.13 -Cerebral infarction due to embolism of left carotid artery. It does not make sense that the value set would not include the dx for stroke due to thrombosis of the left carotid artery, and does not also include the code cerebral infarction due to embolism of the left carotid artery if intent of this data element is to identify patients who have a diagnosis of ischemic stroke, due to thrombosis or embolism.