Cardiovascular service lines across the country were taken by surprise last October, when CMS unveiled an unexpected and potentially paradigm-shifting change to coding and reimbursement for extracorporeal membrane oxygenation (ECMO). In its Inpatient Prospective Payment Systems (IPPS) final rule for fiscal year 2019, CMS announced that it would transition from classifying ECMO by a single ICD-10 procedure code to multiple codes. These codes would distinguish ECMO procedures by mode of vascular cannulation (central or peripheral) and indication (cardiac or respiratory), with different reimbursement for each code.