Imaging Trends in Acute Venous Thromboembolic Disease: 2000 to 2015

To measure diffusion of new knowledge and correlate imaging utilization for suspected acute venous thromboembolism (VTE) with d-dimer utilization, landmark publications, and institutional guidelines.

Between 2000 and 2015, the number of CT pulmonary angiograms (CTPAs), CTPA combined with indirect CT venography (CTV), ventilation-perfusion (VQ) scans, and lower extremity venous Doppler ultrasound (US) examinations were obtained for inpatients and emergency department (ED) patients and correlated with d-dimer utilization, landmark publications regarding radiation and VTE imaging, and an institutional inpatient best-practice alert requiring VTE prophylaxis assessment (2008). Volume data were normalized per 1,000 patients.

CTPA and d-dimer utilization were correlated (ED: r = 0.94, inpatient: r = 0.87; P < .001). VQ volume peaked in 2004 to 2005 (20 of 1,000 ED patients; 14 of 1,000 inpatients) and decreased since to a low of 1 of 1,000 and 3 of 1,000, respectively. US volume increased since 2002 and was higher than CT volume for inpatients (annual mean 149 of 1,000 patients [US], 46 of 1,000 patients [CT]), but not ED patients (annual mean 18 of 1,000 patients [US], 35 of 1,000 patients [CT]). For ED patients, CTPA volume peaked in 2008 at 57 of 1,000 patients, declined through 2012 to 30 of 1,000 patients, and rose annually since to 37 of 1,000 patients (2015). For inpatients, CTPA volume also peaked in 2008 at 70 of 1,000, but continued to decline through 2015 to 27 of 1,000 patients.

After the Prospective Investigation of Pulmonary Embolism II and Brenner and Hall publications, there was a transient 4-year decline in ED CTPA utilization. The decline was sustained in inpatients, where a best-practice VTE prophylaxis alert was implemented. Best-practice alerts may sustain the impact of new knowledge.