Infrainguinal bypass conduit: autogenous or synthetic--a national perspective

Numerous studies have compared autogenous versus synthetic grafts for infrainguinal bypasses. Synthetic grafts are associated with shorter operating times, comparable reimbursement, and despite inferior patency rates, remain in frequent use. Therefore, this study was undertaken in an effort to characterize, from a national perspective, the practice patterns and the drivers of practice variation in the use of synthetic grafts for infrainguinal bypass. Two data sets were obtained: 1) Medicare billings of infrainguinal bypasses in 49 states, years 1995 through 1997 (number of procedures, 254,677). Procedures were defined by nine CPT billing codes. 2) Hospitals over 150 beds in six states (CA, CO, CT, IA, MN, MS) were asked for volume statistics on the same CPT codes. Data were received from 27 institutions, comprising 1,063 procedures. Variations in graft use were analyzed by hospital type (teaching versus non-teaching) and correlated with the prevalence of diabetes mellitus and smoking. Nationwide, 41% of infrainguinal bypasses in 1997 were performed using synthetic grafts. Interstate synthetic conduit use ranged from 27% to 80%. These differences were similar for bypasses to popliteal or infrapopliteal vessels. Admission to a teaching hospital was associated with a lower use of synthetic grafts (21% vs 51%, odds ratio 0.26, p<0.0001). No correlation was seen between the prevalence of diabetes mellitus or smoking, and synthetic graft use. Synthetic graft use was significantly lower at teaching hospitals, and there was substantial interstate and intrastate variations. These findings suggest that there is wide variation in practice patterns. Further studies appear warranted to define the role of patient demographics and physician preference in explaining these differences.