Ask Dr. Z

I audit for a large cardiology practice with several physicians and APPs. In the hospital setting, when critical care is provided, I know split/shared visits are not allowed. However, I have recently been told that an APP is considered to be their own specialty in billing critical care. Also, I have been told that if an APP renders critical care and supports time of 30 minutes or more, they can bill 99291, and then if the cardiologist sees the patient later and critical care is supported, they too can bill 99291. Do you know if this true regarding APPs being their own specialty, as I cannot find this information anywhere?