OBJECTIVES Multi-vessel disease (MVD) is considered in treatment of acute myocardial infarction (AMI) but has been largely unexamined in health economic studies as there is no ICD-9 or 10 diagnosis code. With ICD-10 procedure codes, it is possible to stratify AMI patients by the number of occluded vessels treated. This study introduces the use of ICD-10 procedure codes to measure adverse events and associated costs for AMI patients who receive percutaneous coronary intervention (PCI) by MVD status.

METHODS Eligible patients enrolled in Medicare Fee-for-Service Parts A and B, were admitted with STEMI or NSTEMI between 10/1/2015 and 9/30/2016, and had a PCI during hospitalization. Multi-vessel disease was defined as the involvement of 2 or more cardiac vessels. Major adverse cardiac events (MACE) included recurrent AMI, stroke, or mortality.

RESULTS : The analysis included 53,864 patients (21,666 STEMI; 32,198 NSTEMI). Of these, 7,379 (34.1%) STEMI and 13,665 (42.4%) NSTEMI patients had MVD. MVD was associated with greater use of aspirin; higher rates of comorbidity (diabetes, hypertension, dyslipidemia, and peripheral arterial disease); and recent history of MI or PCI. Compared to patients with single vessel disease, STEMI MVD patients experienced 15% higher rates of MACE (9.2% vs. 8.0%; p<0.01) and NSTEMI MVD patients experienced 23% higher rates (8.6% vs. 6.9%; p=0.0001). In both groups, the increase was attributable to recurrent AMI, as neither stroke nor mortality rates differed by number of affected arteries. MVD patients’ costs of care were $6,079 (STEMI) and $6,497 (NSTEMI) (p <0.0001 for both) higher, due to higher inpatient and professional services costs (NSTEMI only).

CONCLUSIONS : Among AMI patients receiving stents, MVD patients had substantial comorbidity, increased costs, and were more likely to experience recurrent AMI in the 90-days following discharge. These results suggest that MVD patients would benefit from more intensive intervention and support immediately following AMI.