AneuRx Stent-Graft Failure Four Years after TAA Exclusion

Contrast-enhanced ultrasound and/or colour duplex ultrasound for surveillance after endovascular abdominal aortic aneurysm repair: a systematic review and economic evaluation

BACKGROUND

Endovascular abdominal aortic aneurysm repair (EVAR) of abdominal aortic aneurysm (AAA) is less invasive than open surgery, but may be associated with important complications. Patients receiving EVAR require long-term surveillance to detect abnormalities and direct treatments. Computed tomography angiography (CTA) has been the most common imaging modality adopted for EVAR surveillance, but it is associated with repeated radiation exposure and the risk of contrast-related nephropathy. Colour duplex ultrasound (CDU) and, more recently, contrast-enhanced ultrasound (CEU) have been suggested as possible, safer, alternatives to CTA.

OBJECTIVES

To assess the clinical effectiveness and cost-effectiveness of imaging strategies, using either CDU or CEU alone or in conjunction with plain radiography, compared with CTA for EVAR surveillance.

DATA SOURCES

Major electronic databases were searched, including MEDLINE, EMBASE, Science Citation Index, Scopus' Articles-in-Press, Cochrane Central Register of Controlled Trials (CENTRAL), Database of Abstracts of Reviews of Effects (DARE) and NHS Economic Evaluation Database from 1996 onwards. We also searched for relevant ongoing studies and conference proceedings. The final searches were undertaken in September 2016.

METHODS

We conducted a systematic review of randomised controlled trials and cohort studies of patients with AAAs who were receiving surveillance using CTA, CDU and CEU with or without plain radiography. Three reviewers were involved in the study selection, data extraction and risk-of-bias assessment. We developed a Markov model based on five surveillance strategies: (1) annual CTA; (2) annual CDU; (3) annual CEU; (4) CDU together with CTA at 1 year, followed by CDU on an annual basis; and (5) CEU together with CTA at 1 year, followed by CEU on an annual basis. All of these strategies also considered plain radiography on an annual basis.

RESULTS

We identified two non-randomised comparative studies and 25 cohort studies of interventions, and nine systematic reviews of diagnostic accuracy. Overall, the proportion of patients who required reintervention ranged from 1.1% (mean follow-up of 24 months) to 23.8% (mean follow-up of 32 months). Reintervention was mainly required for patients with thrombosis and types I-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 < 1% of the participants. Strategies based on early and mid-term CTA and/or CDU and long-term CDU surveillance were broadly comparable with those based on a combination of CTA and CDU throughout the follow-up period in terms of clinical complications, reinterventions and mortality. The economic evaluation showed that a CDU-based strategy generated lower expected costs and higher quality-adjusted life-year (QALYs) than a CTA-based strategy and has a 63% probability of being cost-effective at a £30,000 willingness-to-pay-per-QALY threshold. A CEU-based strategy generated more QALYs, but at higher costs, and became cost-effective only for high-risk patient groups.

LIMITATIONS

Most studies were rated as being at a high or moderate risk of bias. No studies compared CDU with CEU. Substantial clinical heterogeneity precluded a formal synthesis of results. The economic model was hindered by a lack of suitable data.

CONCLUSIONS

Current surveillance practice is very heterogeneous. CDU may be a safe and cost-effective alternative to CTA, with CTA being reserved for abnormal/inconclusive CDU cases.

FUTURE WORK

Research is needed to validate the safety of modified, more-targeted surveillance protocols based on the use of CDU and CEU. The role of radiography for surveillance after EVAR requires clarification.

STUDY REGISTRATION

This study is registered as PROSPERO CRD42016036475.

FUNDING

The National Institute for Health Research Health Technology Assessment programme.

Toward Endografting of the Ascending Aorta: Insight into Dynamics Using Dynamic Cine-CTA

Purpose:

To evaluate pulsatility and movement along the ascending thoracic aorta using dynamic electrocardiographically-gated 64-slice cine computed tomographic angiography (CTA).

Methods:

Diameter and area change and center of mass (COM) movement of the ascending thoracic aorta was determined per cardiac cycle in 15 patients at surgically relevant anatomical levels: (A) 5 mm distal to the coronary arteries, (B) 5 mm proximal to the innominate artery, and (C) halfway up the ascending aorta. Additionally, COM movement was determined 1 cm (level P) and 2 cm (level Q) distal from the origins of the innominate, left carotid, and left subclavian arteries. Eight gated datasets covering the cardiac cycle were used to reconstruct images at each level perpendicular to the aortic lumen. The distance between important anatomical landmarks was determined.

Results:

All levels showed significant cardiac cycle—induced diameter and area changes (p<0.001), with the largest pulsatility 5 mm distal to the coronary arteries. Mean maximum diameter changes were (A) 17.4%±4.8% (range 7.5%–27.5%), (B) 13.9%±3.5% (range 10.6%–25.0%), and (C) 12.9%±3.4% (8.3%–19.6%). Mean area changes were (A) 12.7%±5.5% (range 4.3%–21.8%), (B) 7.5%±2.0% (range 4.1%–11.0%), and (C) 5.6%±2.2% (range 1.9%–11.4%). Mean maximum COM movements were (A) 6.1±2.0 mm (range 2.7–9.0), (B) 2.3±1.1 mm (range 1.1–5.6), and (C) 3.6±1.5 mm (range 1.4–6.5). Mean COM movements of the innominate, left carotid, and left subclavian arteries, respectively, were (P) 1.960.7 mm (range 0.9–3.7), 2.4±0.6 mm (range 1.4–3.3), and 1.9±0.6 mm (range 0.8–2.8), and (Q) 1.8±0.7 mm (range 0.8–3.5), 1.8±0.6 mm (range 0.8–2.7), 1.9±0.6 mm (range 1.1–3.4).

Conclusion:

The dynamics of the ascending thoracic aorta and the arch vessels are impressive, showing a wide range of 3-dimensional motions. Future ascending arch branched and fenestrated thoracic endograft designs must consider this active local environment, as it may have implications for durability, sealing, and ultimate clinical success.

Mid-term Survival and Costs of Treatment of Patients with Descending Thoracic Aortic Aneurysms; Endovascular vs. Open Repair: a Case-control Study

OBJECTIVES

To evaluate the results of open surgery or endovascular stent graft repair of descending thoracic aortic aneurysm (TAA).

DESIGN, MATERIALS AND METHODS

This is a retrospective multicenter study of 95 patients undergoing TAA repair (42 stent grafts, 53 open repair). The median age was 67 years. Post-operative complications, mid-term survival and costs were assessed. The results were pooled with data in the literature.

RESULTS

After a mean follow up of 26 months (open group) and 15 months (endovascular group) survival was similar for patients treated by either repair method. Post-operative pneumonia was more in the open group (p <0.02). The hospital costs of open treatment were 40% more than that of the endovascular procedure. Combining the present results with pooled data from the literature the peri-operative mortality and paraplegia rate was less in the endovascular group (p <0.05).

CONCLUSIONS

These retrospective data suggest that endografting of descending thoracic aneurysms can be performed with less peri-operative morbidity, at lower hospital costs, but with equal mid-term life expectancy, compared with open grafting.