Background: Guidelines recommend diagnostic non-invasive imaging [arterial duplex ultrasound (DUS), MR angiography (MRA) and CT angiography (CTA)] in patients with symptomatic peripheral arterial disease (PAD) and invasive imaging (diagnostic peripheral angiography) in persistently symptomatic patients despite optimal medical therapy, when revascularization is being considered. Factors predicting the use of imaging and variability in the use of imaging in a real-world PAD population are not known.
Methods: PORTRAIT is a 16-center (US, Netherlands and Australia), prospective registry of patients (confirmed ankle brachial index < 0.9) who were evaluated at a specialty clinic for new or worsening symptoms related to PAD. We compared patient characteristics among those who received non-invasive, invasive, or no diagnostic imaging on their initial visit or during the year prior, using ANOVA and chi-square test. After classifying patients into testing (both invasive and non invasive imaging) and no testing groups, outcomes were assessed using a 3 level hierarchical logistic regression model (patient-provider-site). Median Odds Ratio (MOR) was calculated to examine site variability in ordering imaging tests.
Results: Of the 1275 patients, 50.7% patients had a non-invasive imaging test (42.3% DUS, 9.7% CTA, 5.2% MRA), 4.9% had invasive imaging and 48.5% did not receive any imaging. Patients receiving non-invasive imaging had less severe symptoms of shorter duration, were not active smokers and less likely to have had a prior PAD intervention. There was significant site variability in the use of diagnostic imaging [ MOR= 3.04 (2-6.4; p = <0.001, Figure)].
Conclusion: There is a significant variation in the utilization of diagnostic imaging in symptomatic PAD patients across sites and countries. Further studies are needed to better understand the impact of testing on clinical decision-making and outcomes in these patients.