Outcomes and total costs of outpatient vs. inpatient peri-procedural anticoagulation management of mechanical prosthetic heart valve patients

Background/objectives The most cost-effective periprocedural management of patients with mechanical heart valves (MHV) is uncertain. The objective was to compare the effectiveness, safety and costs for inpatient intravenous unfractionated heparin (IVUH) vs. outpatient low molecular weight heparin (LMWH) "bridging" as periprocedural anticoagulation management for MHV patients. Methods In a case-cohort study, Olmsted County, MN residents with MHV who received outpatient periprocedural LMWH management (cases) over the 11-year period, 1997-2007, were matched to residents with MHV who received inpatient IVUH periprocedural management on valve location and type, and on procedure type. Patients were followed for 3 months following hospitalization to identify thromboembolism (TE) and major bleeding. Total costs from 30 days before to 90 days after the procedure were determined from the Olmsted County Healthcare Expenditure and Utilization Database. Outcomes were compared using survival analysis and costs were compared using the Wilcoxon rank sum. Results 149 cases (100 aortic, 29 mitral, 20 both; 64% bileaflet) were compared to 149 cohort members (100 aortic, 29 mitral, 20 both; 75% bileaflet). While the 3-month cumulative incidence of TE did not differ significantly among cases (2.7%) and cohort members (4.7%; p = 0.36), major bleeding was significantly lower in cases (5.4% vs. 15.4%; p < 0.005). Total costs were significantly higher for cohort members ($50,984 vs. $39,347; p = 0.002) due to higher inpatient costs ($47,729 vs. $34,860; p = 0.0002). Conclusions Outpatient bridging LMWH therapy is equally effective, but safer and less costly than inpatient IVUH as periprocedural anticoagulation management for MHV patients.