Duplex ultrasound for surveillance after endovascular repair of abdominal aortic aneurysm

Aim. Surveillance after endovascular aneurysm repair (EVAR) is essential in the detection of endoleaks. Conventional surveillance uses contrast-enhanced computed tomography (CT) but this exposes patients to radiation and nephrotoxic contrast agents as well as being relatively expensive. Duplex ultrasound (USS) is cheaper and does not use nephrotoxic contrast agents but is considered less accurate. The aim of this study was to review the accuracy of duplex ultrasound compared to the "gold-standard" of contrast enhanced CT for endoleak detection. Methods. Medline, Google scholar and reference lists of articles were searched to identify trials with paired scan data comparing USS and contrast enhanced CT for endoleak surveillance post-EVAR. Results. Twenty-nine studies comparing 5343 paired scans were included. Pooled sensitivity of USS was 0.62 (95% CI 0.58 - 0.65) and pooled specificity was 0.94 (95% CI 0.93-0.94). Pooled positive predictive value of USS was 0.67 (95% CI 0.63-0.69) and negative predictive value was 0.94 (95% CI 0.93-0.94). Conclusion. USS has a relatively low sensitivity but a high specificity for the detection of endoleak after EVAR compared with CT. It is good at detecting clinically significant endoleaks.