The clinical and cost-effectiveness of protocols using contrast-enhanced ultrasound and/or colour duplex ultrasound in the long-term surveillance of endovascular abdominal aortic aneurysm repair (EVAR): an evidence synthesis and economic evaluation
Endovascular repair (EVAR) of an abdominal aortic aneurysm is a minimally invasive surgical technique but is associated with potential serious complications. EVAR patients require long-term surveillance to detect abnormalities and direct treatments. Computed tomography angiography (CTA) is widely used but carries the risk of repeated radiation exposure and of contrast-related nephropathy. Colour duplex (CDU) and contrast-enhanced (CEU) ultrasound have been suggested as possible, safer, alternatives.
This NIHR Health Technology Assessment Programme funded project assessed the clinical effectiveness and cost-effectiveness of imaging strategies for surveillance after EVAR. Clinical effectiveness evidence was derived from 2 non-randomised comparative studies, 25 cohort studies, and 9 systematic reviews of diagnostic accuracy. Substantial clinical heterogeneity precluded a formal synthesis of results. Most studies were at high or moderate risk of bias. No studies directly compared CDU with CEU. In general, strategies based on early and midterm CTA and/or CDU and long term CDU surveillance were broadly comparable with those based on a combination of CTA and CDU throughout follow up in terms of clinical complications, re-interventions, and mortality.
The proportion of patients requiring re-intervention ranged from 1.1% (mean follow-up 24 months) to 23.8% (mean follow-up 32 months). Re-intervention was mainly required for thrombosis and types I, II and III endoleaks. All-cause mortality ranged from 2.7% (mean follow-up of 24 months) to 42% (mean follow-up of 54.8 months). Aneurysm-related mortality occurred in less than 1% of participants. Our economic evaluation showed that a CDU-based strategy generated lower expected costs and higher QALYs than a CTA-based strategy. A CEU-based strategy generated more QALYs, but at higher costs, and became cost-effective only for the high risk patient group.
Further research is needed to assess the value of a more targeted surveillance (i.e., according to patients’ risk of complications) and validate the safety of modified CDU and CEU surveillance protocols.
Miriam Brazzelli; firstname.lastname@example.org
Brazzelli, M, Hernandez, R, Sharma, P, Robertson, C, Shimonovich, M, MacLennan, G, Fraser, C, Jamieson, R, Vallabhaneni, S The clinical and cost-effectiveness of protocols using contrast-enhanced ultrasound and/or colour duplex ultrasound in the long-term surveillance of endovascular abdominal aortic aneurysm repair: an evidence synthesis and economic evaluation. Health Technol Assess 2017 (accepted for publication)