Trends in noninvasive vascular test utilization

Trends in noninvasive vascular test (NIVT) utilization are not well defined. The objective of this study was to examine the changes in NIVT utilization since the introduction of color flow duplex ultrasonography. Prospectively maintained logbooks were reviewed at 2 separate vascular laboratories (MMC-VL and SJH-VL), each associated with a tertiary care center in the same city. NIVTs were grouped as lower extremity arterial, aorto-renal-visceral, carotid, venous, and other. Physicians requesting NIVTs were designated to 1 of 10 specialties. For MMC-VL, NIVTs grew from 2979 performed in 1992 to 6720 performed in 1998, representing an average annual increase of 21%. In 1992 and 1998, the predominant specialties requesting NIVTs at MMC-VL were internists (40 and 27% of NIVTs, respectively), vascular surgeons (13 and 33%, respectively), and cardiologists (12 and 12%, respectively). For SJH-VL, NIVTs grew from 4427 performed in 1994 to 5651 performed in 1998, representing an average annual increase of 7%. In 1994 and 1998, the predominant specialties requesting NIVTs at SJH-VL were cardiologists (29 and 36% of NIVTs, respectively), internists (40 and 28%, respectively), and vascular surgeons (9 and 8%, respectively). The average annual increase in medical staff appointments to each hospital associated with MMC-VL and SJH-VL was 3.8% (514 to 593) and 3.1% (493 to 585), respectively. Ninety-six percent of the medical staff had privileges at both hospitals. A dramatic increase in the number of NIVTs was observed over time at 2 vascular laboratories in the same city. This growth outpaced physician growth, indicating an increase in the ratio of tests requested to number of physicians. Cardiologists, internists, and vascular surgeons requested the large majority of NIVTs, with cardiologists requesting approximately 19% more NIVTs per year at each vascular laboratory. In response to these trends, more vascular technologists may be needed as well as increased emphasis on maintaining high-quality NIVTs.