Benefits of Completion 3D Angiography Associated with Contrast Enhanced Ultrasound to Assess Technical Success after EVAR

Intraoperative computed tomography during fenestrated and branched endovascular aortic repair: a feasibility study

BACKGROUND

Endovascular aortic repair with fenestrated or branched endografts is technically challenging, and proper intraoperative assessment of all stent graft components with only angiography and fluoroscopy can be difficult. Intraoperative computed tomography (CT) imaging can be a valuable aid for the operators in the evaluation of stent grafting results prior to completion of surgery.

PURPOSE

To examine the feasibility of performing intraoperative CT imaging during fenestrated and branched endovascular aortic repair (f-bEVAR) under sterile conditions and with patients under general anesthesia.

MATERIAL AND METHODS

Intraoperative CT imaging was performed in 10 patients undergoing elective aortic repair with fenestrated or branched endografts. Adverse events, time consumption for CT set-up and image acquisition, and additional radiation dose to the patient were recorded. CT image quality was graded. Immediate corrective maneuvers performed based on the CT findings was registered.

RESULTS

There were no adverse events related to intraoperative CT imaging. The median additional operating time by including intraoperative CT was 16 min (interquartile range [IQR] = 12-19), comprising 7% of the median total operating time. The median estimated additional radiation dose to the patient was 4.8 mSv (IQR = 3.8-4.9). All intraoperative CT examinations were considered to be of sufficient quality for stent graft evaluation. No immediate corrective procedures were performed on the basis of CT findings in this study cohort.

CONCLUSION

CT imaging intraoperatively during f-bEVAR is feasible with an acceptable increase in operating time and radiation dose.

Fully Ultrasound-Assisted Endovascular Aneurysm Repair (EVAR): preliminary report

BACKGROUND

Reducing fluoroscopy times and iodine contrast administration during endovascular exclusion (EVAR) of infrarenal aortic aneurysms (AAA) remains a challenge. The purpose of this study was to evaluate the preliminary results of a fully ultrasound-assisted EVAR without iodine contrast administration.

METHODS

Twentyseven consecutive patients, underwent an elective IVUS-assisted EVAR with final CEUS control of correct aneurysm exclusion. In no case intraprocedural injection of iodine contrast medium was performed. The primary study's endpoints were the overall duration of the procedure, duration of fluoroscopy, cumulative radiation dose, the length of intraoperative CEUS control and the comparison of findings between intraoperative CEUS and CT-scan at one month.

RESULTS

Mean duration of the procedure was 130 ± 35 minutes. Overall duration of fluoroscopy was 22 ± 18 minutes. Mean radiation dose was 66 mGy (range, 24 - 82). The mean length of CEUS final control was 8 ± 2 minutes. No type I or type III endoleak was detected either at CEUS or at angio-CT scan at one month from EVAR. CEUS revealed a type II endoleak in 6 patients (22%) , compared to 9 type II endoleaks (33%) detected at angio-CT scan one month after the procedure (p = 0.5).

CONCLUSIONS

Fully ultrasound (IVUS and CEUS) -assisted EVAR is safe, feasible and reliable, completely eliminating the need for iodine contrast medium and reducing the radiation exposure for both patients and surgeons.

Intraoperative cone beam computed tomography to improve outcomes after infra-renal endovascular aortic repair

OBJECTIVE

To evaluate whether a combination of intraoperative ceCBCT and postoperative contrast enhanced ultrasound (CEUS) assessment after infra-renal endovascular aortic repair (EVAR) could reduce late stent-graft related complications and consequently re-interventions.

METHODS

All consecutive patients receiving infra-renal bifurcated stent-grafts in our hybrid room (IGS 730, GE Healthcare) during two discrete periods were included in this study: i) from November 2012 to September 2013, a 2D completion angiogram was performed after each EVAR, followed by computed tomography angiography (CTA) before discharge (group 1), ii) from October 2013 to January 2015, an intraoperative ceCBCT was performed, followed by CEUS within the first postoperative days (group 2). Comparative analyses of outcomes were undertaken. The primary endpoint was late stent-graft related complications, a composite factor incorporating aneurysm-related death, type 1 or 3 endoleaks, kink or occlusion of iliac limb and aortic sac enlargement beyond the first 30 postoperative days. The secondary endpoint was all stent-graft related re-interventions. All-cause and aneurysm related deaths were also reported.

RESULTS

Overall, 100 consecutive patients (50 in group 1 and 50 in group 2) were enrolled with a median follow up of 60 months [IQR 41-69]. At 60 months from the index procedure, freedom from late stent-graft related complications in each group was 61.6% (95 % CI [47.0-80.6]) for group 1 and 81.7% (95 % CI [70.1-95.2]) for group 2 (p=.033). Intraoperative CBCT was independently associated with a reduced rate of late stent-graft related complications after multivariate analysis (HR = 0.39, 95% CI 0.16-0.95, p=.038), but did not appear to significantly protect against stent-graft related re-interventions (HR=0.53; 95% CI 0.20-1.39, p=.198) or all cause death (p=.47).

CONCLUSION

This study is the first to report the influence of routine ceCBCT on late outcomes after EVAR and shows a potential reduction in late stent-graft related complications associated with its use.

The Utility of Intraoperative Contrast-enhanced Ultrasound for Immediate Treatment of Type Ia Endoleak during EVAR: Initial Experience

Objectives:

Type Ia endoleak (EL) after endovascular abdominal aortic repair (EVAR) may be misdiagnosed at completion angiography. Intraoperative contrast-enhanced ultrasound (CEUS) may play a role in early detection and immediate treatment of type Ia EL.

Methods:

From January 2017 to April 2018, patients treated with EVAR underwent intraoperative CEUS. After endograft deployment and ballooning, digital subtraction angiography (DSA) and intraoperative CEUS were performed in a blinded fashion. All cases of type Ia EL at DSA or CEUS were considered.

Results:

Type Ia EL detected at intraoperative CEUS and undetected at DSA was defined in 2 patients. The former was solved with intraoperative re-ballooning; in the latter case, a Palmaz stent deployment was required. The resolution of type Ia EL was detected at intraoperative CEUS control and post-operative computed tomography angiography (CTA). In another patient, the DSA detected a type Ia EL, but intraoperative CEUS reveal a type II EL from lumbar arteries. Post-operative CTA confirm the type II EL.

Conclusions:

The reported cases prove the clinical utility of the intraoperative CEUS, permitting the early identification of 2 type Ia EL. In addition, the intraoperative CEUS is useful in case of dubious type Ia EL at DSA, avoiding unnecessary intraoperative adjunctive procedure or post-operative CTA. (www.actabiomedica.it)

Impact of Hybrid Operating Rooms on Long-Term Clinical Outcomes Following Fenestrated and Branched Endovascular Aortic Repair

PURPOSE

Evaluate the impact of hybrid operating room (HOR) guidance on the long-term clinical outcomes following fenestrated and branched endovascular repair (F-BEVAR) for complex aortic aneurysms.

MATERIALS AND METHODS

Prospectively collected registry data were retrospectively analyzed to compare the procedural, short- and long-term outcomes of consecutive F-BEVAR performed from January 2010 to December 2014 under standard mobile C-arm versus hybrid room guidance in a high-volume aortic center.

RESULTS

A total of 262 consecutive patients, including 133 patients treated with a mobile C-arm equipped operating room and 129 with a HOR guidance, were enrolled in this study. Patient radiation exposure and contrast media volume were significantly reduced in the HOR group. Short-term clinical outcomes were improved despite higher case complexity in the HOR group, with no statistical significance. At a median follow-up of 63.3 months (Q1 33.4, Q3 75.9) in the C-arm group, and 44.9 months (Q1 25.1, Q3 53.5, p=0.53) in the HOR group, there was no statistically significant difference in terms of target vessel occlusion and limb occlusion. When the endograft involved 3 or more fenestrations and/or branches (complex F-BEVAR), graft instability (36% vs 25%, p=0.035), reintervention on target vessels (20% vs 11%, p=0.019) and total reintervention rates (24% vs 15%, p=0.032) were significantly reduced in the HOR group. The multivariable Cox regression analysis did not show statistically significant differences for long-term death and aortic-related death between the 2 groups.

CONCLUSION

Our study suggests that better long-term clinical outcomes could be observed when performing complex F-BEVAR in the latest generation HOR.

Intra-operative computed tomography in endovascular aneurysm repair

The study objective was to evaluate the ability of computed tomography (CT) to identify technical complications intra-operatively during endovascular aneurysm repair (EVAR). Frequency of complications seen by CT and their sequelae was compared with conventional completion angiography.

METHODS

We performed a systematic review that conformed to the Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA) guidelines. We considered studies reporting on the effectiveness of intra-operative CT during EVAR.

RESULTS

Our literature search yielded six studies that met our criteria for inclusion. In general, these showed intra-operative CT to be superior to completion angiogram at detecting intra-operative complications during EVAR. Despite concerns regarding irradiation, the use of intra-operative CT was found to expose patients to an overall lower radiation dose, since post-operative CT angiograms were no longer required. Moreover, no adverse effect on renal function has been demonstrated as a result of the increased intra-operative contrast usage when CT is used.

CONCLUSIONS

The current body of evidence suggests that intra-operative CT is superior to completion angiography at detecting clinically important EVAR complications and incurs a lower total radiation dose with no added risk of contrast-induced renal impairment. Further research directly comparing the two modalities in the same cohort is required to determine sensitivity for individual complications.

Comparison of Contrast-Enhanced Tomographic 3-D Ultrasound Against Rotational Angiography Imaging Immediately After Endovascular Aneurysm Repair

This proof of principle study assesses the utility of contrast-enhance ultrasound (CEUS) and contrast-enhanced tomographic 3-D ultrasound (CEtUS), as an intra-procedural imaging tool after endovascular-aneurysm repair (EVAR), compared with rotational angiography. A total of 20 consecutive patients undergoing infra-renal EVAR underwent immediate post-deployment rotational angiography, followed by CEUS and CEtUS scans. Outcomes were presence of endoleak, renal artery patency and endograft deformity. CEUS and CEtUS detected 12 endoleaks, 8 of which were not detected by rotational angiography. CEUS and CEtUS classify 7 or 8 type IIb endoleaks not detected by rotational angiography. CEUS/CEtUS could not identify 12 and 13 renal arteries, respectively, detected by rotational angiography. Rotational angiography and CEtUS both identified 1 endograft limb deformity, corrected immediately. CEUS and CEtUS are more sensitive to type II endoleak than rotational angiography, although there is a lower detection of renal arteries. CEUS or CEtUS has the utility for immediate post-EVAR endoleak detection where reduction of contrast agent is indicated.

Intraoperative contrast-enhanced ultrasound for early diagnosis of endoleaks during endovascular abdominal aortic aneurysm repair

BACKGROUND

The aim of this study was to evaluate the feasibility and utility of intraoperative contrast-enhanced ultrasound (CEUS) for early detection of endoleaks (ELs) during endovascular abdominal aortic aneurysm repair (EVAR) compared with completion digital subtraction angiography.

METHODS

Patients undergoing elective EVAR from January 2017 to April 2018 were consecutively enrolled in this prospective study. After endograft deployment, two-digital subtraction angiography (2DSA) with orthogonal C-arm angulations (anteroposterior and sagittal view) were routinely performed. After the endovascular treatment of clear, high-flow type I/III ELs detected by 2DSA, intraoperative CEUS was carried out in sterile conditions on the surgical field before guidewire removal. Presence and type of EL were evaluated with 2DSA and CEUS. CEUS was performed with the vascular surgeon blinded to the 2DSA findings. The primary end point was the level of agreement between 2DSA and CEUS to detect any type of EL and type II EL. Agreement between two diagnostic methods was calculated using Cohen's kappa. The secondary end point was utility of CEUS for intraoperative adjunctive procedure guidance.

RESULTS

Sixty patients were enrolled (mean age, 78 ± 6 years; 90% male). 2DSA revealed 11 ELs (18%; 1 type IA, 10 type II), and CEUS 25 ELs (42%; 2 type IA, 23 type II). 2DSA and CEUS were in agreement in 39 cases (65%; 32 no ELs, 7 type II ELs). CEUS detected 17 ELs not identified by 2DSA (28%; 2 type IA, 15 type II); 2DSA detected three ELs not identified by CEUS (5%; 3 type II). In one case, 2DSA and CEUS detected type II and type IA ELs, respectively. For EL and type II EL detection, Cohen's kappa was 0.255 and 0.250, respectively (both "fair agreement"). Intraoperative adjunctive sac embolization was performed under CEUS control in 4 cases and technical success was 100%.

CONCLUSIONS

Intraoperative CEUS during EVAR is feasible and can detect a greater number of ELs than 2DSA, in particular type II ELs. Further studies are necessary to assess the reliability of this intraoperative diagnostic examination. In type II ELs, CEUS may represent an additional, useful tool for intraoperative sac embolization guidance.

Optimizing imaging and reducing radiation exposure during complex aortic endovascular procedures

Improvements in endovascular technologies and development of custom-made fenestrated and branched endografts currently allow clinicians to treat complex aortic lesions such as thoraco-abdominal and aortic arch aneurysms once treatable with open repair only. These advances are leading to an increase in the complexity of endovascular procedures which can cause long operation times and high levels of radiation exposure. This in turn places pressure on the vascular surgery community to display more superior interventional skills and radiological practices. Advanced imaging technology in this context represents a strong pillar in the treatment toolbox for delivering the best care at the lowest risk level. Delivering the best patient care while managing the radiation and iodine contrast media risks, especially in frail and renal impaired populations, is the challenge aortic surgeons are facing. Modern hybrid rooms are equipped with a wide range of new imaging applications such as fusion imaging and cone-beam computed tomography (CBCT). If these technologies contribute to reducing radiation, they can be complex and intimidating to master. The aim of this review is to discuss the fundamentals of good radiological practices and to describe the various imaging tools available to the aortic surgeon, both those available today and those we anticipate will be available in the near future, from equipment to software, to perform safe and efficient complex endovascular procedures.

Accuracy of implementing principles of fusion imaging in the follow up and surveillance of complex aneurysm repair

Fusion imaging is standard for the endovascular treatment of complex aortic aneurysms, but its role in follow up has not been explored. A critical issue is renal function deterioration over time. Renal volume has been used as a marker of renal impairment; however, it is not reproducible and remains a complex and resource-intensive procedure. The aim of this study is to determine the accuracy of a fusion-based software to automatically calculate the renal volume changes during follow up. In this study, computerized tomography (CT) scans of 16 patients who underwent complex aortic endovascular repair were analysed. Preoperative, 1-month and 1-year follow-up CT scans have been analysed using a conventional approach of semi-automatic segmentation, and a second approach with automatic segmentation. For each kidney and at each time point the percentage of change in renal volume was calculated using both techniques. After review, volume assessment was feasible for all CT scans. For the left kidney, the intraclass correlation coefficient (ICC) was 0.794 and 0.877 at 1 month and 1 year, respectively. For the right side, the ICC was 0.817 at 1 month and 0.966 at 1 year. The automated technique reliably detected a decrease in renal volume for the eight patients with occluded renal arteries during follow up. This is the first report of a fusion-based algorithm to detect changes in renal volume during postoperative surveillance using an automated process. Using this technique, the standardized assessment of renal volume could be implemented with greater ease and reproducibility and serve as a warning of potential renal impairment.

[Thoracoabdominal aneurysms]

Endovascular treatment of thoracoabdominal aneurysms: what's new? Thoracoabdominal aneurysms (T-AAA) are aortic aneurysms that involve both the thoracic and abdominal segments of the aorta and its associated visceral branches. Although the first successful open repair was reported over 50 years ago, the risks of treatment remain considerable. As the first generations of devices available for endovascular aneurysm repair (EVAR) were relatively simple tubes or bifurcated grafts, initial attempts to extend the benefits of EVAR to patients with T-AAA lead to "hybrid solution". Good results with hybrid repairs have not been universal and the approach does not exploit all of the potential advantages of a "pure" endovascular approach (lesser surgical insult). This unmet need, together with rapid technological advances, has encouraged the development of custom-made endografts with fenestrations and/or branches (F-BEVAR) for extension into the visceral vessel ostia. F-BEVAR requires considerably more complex device design and planning than conventional EVAR. Deployment is more technically demanding and takes longer to complete. Thus, patient, aneurysm anatomy and surgical team selection is paramount. Favorable outcomes have been widely reported following T-AAA repair with F-BEVAR in expert centers; more complex aortic lesions such as T-AAA in the context of chronic dissection or arch aneurysms are thus now also offered endovascular repair with F-BEVAR.

Defining the Key Competencies in Radiation Protection for Endovascular Procedures: A Multispecialty Delphi Consensus Study

OBJECTIVES

Radiation protection training courses currently focus on broad knowledge topics which may not always be relevant in daily practice. The goal of this study was to determine the key competencies in radiation protection that every endovascular team member should possess and apply routinely, through multispecialty clinical content expert consensus.

METHODS

Consensus was obtained through a two round modified Delphi methodology. The expert panel consisted of European vascular surgeons, interventional radiologists, and interventional cardiologists/angiologists experienced in endovascular procedures. An initial list of statements, covering knowledge skills, technical skills and attitudes was created, based on a literature search. Additional statements could be suggested by the experts in the first Delphi round. Each of the statements had to be rated on a 5- point Likert scale. A statement was considered to be a key competency when the internal consistency was greater than alpha = 0.80 and at least 80% of the experts agreed (rating 4/5) or strongly agreed (rating 5/5) with the statement. Questionnaires were emailed to panel members using the Surveymonkey service.

RESULTS

Forty-one of 65 (63.1%) invited experts agreed to participate in the study. The response rates were 36 out of 41 (87.8%): overall 38 out of 41(92.6%) in the first round and 36 out of 38 (94.7%) in the second round. The 71 primary statements were supplemented with nine items suggested by the panel. The results showed excellent consensus among responders (Cronbach's alpha = 0.937 first round; 0.958 s round). Experts achieved a consensus that 30 of 33 knowledge skills (90.9%), 23 of 27 technical skills (82.1%), and 15 of 20 attitudes (75.0%) should be considered as key competencies.

CONCLUSIONS

A multispecialty European endovascular expert panel reached consensus about the key competencies in radiation protection. These results may serve to create practical and relevant radiation protection training courses in the future, enhancing radiation safety for both patients and the entire endovascular team.

Ultrasonography for endoleak detection after endoluminal abdominal aortic aneurysm repair

BACKGROUND

People with abdominal aortic aneurysm who receive endovascular aneurysm repair (EVAR) need lifetime surveillance to detect potential endoleaks. Endoleak is defined as persistent blood flow within the aneurysm sac following EVAR. Computed tomography (CT) angiography is considered the reference standard for endoleak surveillance. Colour duplex ultrasound (CDUS) and contrast-enhanced CDUS (CE-CDUS) are less invasive but considered less accurate than CT.

OBJECTIVES

To determine the diagnostic accuracy of colour duplex ultrasound (CDUS) and contrast-enhanced-colour duplex ultrasound (CE-CDUS) in terms of sensitivity and specificity for endoleak detection after endoluminal abdominal aortic aneurysm repair (EVAR).

SEARCH METHODS

We searched MEDLINE, Embase, LILACS, ISI Conference Proceedings, Zetoc, and trial registries in June 2016 without language restrictions and without use of filters to maximize sensitivity.

SELECTION CRITERIA

Any cross-sectional diagnostic study evaluating participants who received EVAR by both ultrasound (with or without contrast) and CT scan assessed at regular intervals.

DATA COLLECTION AND ANALYSIS

Two pairs of review authors independently extracted data and assessed quality of included studies using the QUADAS 1 tool. A third review author resolved discrepancies. The unit of analysis was number of participants for the primary analysis and number of scans performed for the secondary analysis. We carried out a meta-analysis to estimate sensitivity and specificity of CDUS or CE-CDUS using a bivariate model. We analysed each index test separately. As potential sources of heterogeneity, we explored year of publication, characteristics of included participants (age and gender), direction of the study (retrospective, prospective), country of origin, number of CDUS operators, and ultrasound manufacturer.

MAIN RESULTS

We identified 42 primary studies with 4220 participants. Twenty studies provided accuracy data based on the number of individual participants (seven of which provided data with and without the use of contrast). Sixteen of these studies evaluated the accuracy of CDUS. These studies were generally of moderate to low quality: only three studies fulfilled all the QUADAS items; in six (40%) of the studies, the delay between the tests was unclear or longer than four weeks; in eight (50%), the blinding of either the index test or the reference standard was not clearly reported or was not performed; and in two studies (12%), the interpretation of the reference standard was not clearly reported. Eleven studies evaluated the accuracy of CE-CDUS. These studies were of better quality than the CDUS studies: five (45%) studies fulfilled all the QUADAS items; four (36%) did not report clearly the blinding interpretation of the reference standard; and two (18%) did not clearly report the delay between the two tests.Based on the bivariate model, the summary estimates for CDUS were 0.82 (95% confidence interval (CI) 0.66 to 0.91) for sensitivity and 0.93 (95% CI 0.87 to 0.96) for specificity whereas for CE-CDUS the estimates were 0.94 (95% CI 0.85 to 0.98) for sensitivity and 0.95 (95% CI 0.90 to 0.98) for specificity. Regression analysis showed that CE-CDUS was superior to CDUS in terms of sensitivity (LR Chi² = 5.08, 1 degree of freedom (df); P = 0.0242 for model improvement).Seven studies provided estimates before and after administration of contrast. Sensitivity before contrast was 0.67 (95% CI 0.47 to 0.83) and after contrast was 0.97 (95% CI 0.92 to 0.99). The improvement in sensitivity with of contrast use was statistically significant (LR Chi² = 13.47, 1 df; P = 0.0002 for model improvement).Regression testing showed evidence of statistically significant effect bias related to year of publication and study quality within individual participants based CDUS studies. Sensitivity estimates were higher in the studies published before 2006 than the estimates obtained from studies published in 2006 or later (P < 0.001); and studies judged as low/unclear quality provided higher estimates in sensitivity. When regression testing was applied to the individual based CE-CDUS studies, none of the items, namely direction of the study design, quality, and age, were identified as a source of heterogeneity.Twenty-two studies provided accuracy data based on number of scans performed (of which four provided data with and without the use of contrast). Analysis of the studies that provided scan based data showed similar results. Summary estimates for CDUS (18 studies) showed 0.72 (95% CI 0.55 to 0.85) for sensitivity and 0.95 (95% CI 0.90 to 0.96) for specificity whereas summary estimates for CE-CDUS (eight studies) were 0.91 (95% CI 0.68 to 0.98) for sensitivity and 0.89 (95% CI 0.71 to 0.96) for specificity.

AUTHORS' CONCLUSIONS

This review demonstrates that both ultrasound modalities (with or without contrast) showed high specificity. For ruling in endoleaks, CE-CDUS appears superior to CDUS. In an endoleak surveillance programme CE-CDUS can be introduced as a routine diagnostic modality followed by CT scan only when the ultrasound is positive to establish the type of endoleak and the subsequent therapeutic management.

Translumbar Puncture for Retrograde Catheterization of a Kinked Left Renal Stent After Fenestrated Endograft Repair

Purpose: To describe a case of percutaneous retrograde left renal artery cannulation and restenting for severe distortion of a bridging stent diagnosed at the time of fenestrated endovascular aneurysm repair (FEVAR). Case Report: A 79-year-old man underwent 4-vessel FEVAR, during which completion angiography showed a good postoperative result, but cone beam computed tomography (CBCT) demonstrated severe distortion of the proximal part of the left renal stent. An antegrade or hybrid approach to recannulate the vessel was not possible due to the stent architecture and patient comorbidities. Contrast-enhanced CBCT was used to define the needle trajectory for a percutaneous translumbar approach. Fusion imaging software registered the planned needle track to the live fluoroscopy image. Respiratory motion compensation was used. Retrograde cannulation of the left renal artery was achieved; via a through-and-through wire with the left femoral artery, the left renal artery stent was relined using a covered stent. No deterioration of renal function was observed following the procedure. Contrast-enhanced duplex ultrasound demonstrated good flow in all target vessels without endoleak. Conclusion: Translumbar puncture and retrograde catheterization of a severely distorted left renal artery stent is possible during FEVAR using advanced imaging applications and can prevent target vessel loss.

A Systematic Review of Ultrasound or Magnetic Resonance Imaging Compared With Computed Tomography for Endoleak Detection and Aneurysm Diameter Measurement After Endovascular Aneurysm Repair

PURPOSE

To analyze the literature comparing ultrasound [duplex (DUS) or contrast-enhanced (CEUS)] or magnetic resonance imaging (MRI) with computed tomography angiography (CTA) for endoleak detection and aneurysm diameter measurement after endovascular aneurysm repair (EVAR).

METHODS

A systematic review identified 31 studies that included 3853 EVAR patients who had paired scans (DUS or CEUS vs CTA or MRI vs CTA) within a 1-month interval for identification of endoleaks during EVAR surveillance. The primary outcome was the number of patients with an endoleak detected by one test but undetected by another test. Results are presented for all endoleaks and for types I and III endoleaks only. Aneurysm diameter measurements between CTA and ultrasound were examined using meta-analysis.

RESULTS

Endoleaks were seen in 25.6% (985/3853) of patients after EVAR. Fifteen studies compared DUS with CTA for the detection of all endoleak types. CTA had a significantly higher proportion of additional endoleaks detected (214/2346 vs 77/2346 for DUS). Of 19 studies comparing CEUS with CTA for the detection of all endoleak types, CEUS was more sensitive (138/1694) vs CTA (51/1694). MRI detected 42 additional endoleaks that were undetected by CTA during the paired scans, whereas CTA detected 2 additional endoleaks that MRI did not show. CTA had a similar proportion of additional types I and III endoleaks undetected by CEUS or MRI. Of 9 studies comparing ultrasound vs CTA for post-EVAR aneurysm diameter measurement, the aneurysm diameter measured by CTA was greater than ultrasound (mean difference -1.70 mm, 95% confidence interval -2.45 to -0.96, p<0.001).

CONCLUSION

This study demonstrated that CEUS and MRI are more accurate than CTA for the detection of post-EVAR endoleaks, but they are no better than CTA for detecting types I and III endoleaks specifically. Aneurysm diameter differences between CTA and ultrasound should be considered when evaluating the change in aneurysm diameter postoperatively.

Aortic dissection

Aortic dissection is a life-threatening condition caused by a tear in the intimal layer of the aorta or bleeding within the aortic wall, resulting in the separation (dissection) of the layers of the aortic wall. Aortic dissection is most common in those 65-75 years of age, with an incidence of 35 cases per 100,000 people per year in this population. Other risk factors include hypertension, dyslipidaemia and genetic disorders that involve the connective tissue, such as Marfan syndrome. Swift diagnostic confirmation and adequate treatment are crucial in managing affected patients. Contemporary management is multidisciplinary and includes serial non-invasive imaging, biomarker testing and genetic risk profiling for aortopathy. The choice of approach for repairing or replacing the damaged region of the aorta depends on the severity and the location of the dissection and the risks of complication from surgery. Open surgical repair is most commonly used for dissections involving the ascending aorta and the aortic arch, whereas minimally invasive endovascular intervention is appropriate for descending aorta dissections that are complicated by rupture, malperfusion, ongoing pain, hypotension or imaging features of high risk. Recent advances in the understanding of the underlying pathophysiology of aortic dissection have led to more patients being considered at substantial risk of complications and, therefore, in need of endovascular intervention rather than only medical or surgical intervention.

Comparison of Radiation Exposure Associated With Intraoperative Cone-Beam Computed Tomography and Follow-up Multidetector Computed Tomography Angiography for Evaluating Endovascular Aneurysm Repairs

Purpose: To compare the radiation exposure associated with intraoperative contrast-enhanced cone-beam computed tomography (ceCBCT) acquisitions to standard 3-phase multidetector computed tomography (MDCT) angiography used for assessing technical success after endovascular aortic repair (EVAR). Methods: Effective doses (EDs) were calculated for 66 EVAR patients (mean age 71 years; 61 men) with a mean 27.7-kg/m2 body mass index (range 17–49) who had both intraoperative ceCBCT and postoperative 3-phase MDCT angiography between November 2012 and April 2015. In addition, EDs were directly determined using thermoluminescent dosimeters (TLDs) embedded in anthropomorphic phantoms with body mass indexes of 22 and 30 kg/m2. Effective doses were calculated by summing doses recorded by all TLDs corresponding to a specific tissue type before applying the International Commission on Radiological Protection (ICRP) 60 and 103 weighting factors. EDs were compared with each other for both imaging modalities as well as to TLD measurements. Results: Average EDs of the patient collective were 4.9±1.1 mSv for ceCBCT, 2.6±1.2 mSv for single-phase MDCT (46% decrease, covering solely the area of the implanted endograft), and 13.6±5.5 mSv for comprehensive 3-phase MDCT examinations (178% increase, anatomical coverage from the aortic arch to femoral artery bifurcation). EDs determined in phantom measurements ranged from 3.1 to 4.5 mSv for ceCBCT, amounting to 2.6 mSv for a single MDCT phase (15% to 40% decrease) using ICRP 60 conversion factors. Applying ICRP 103 factors resulted in higher values for ceCBCT and slightly lower ones for MDCT. Conclusion: ceCBCT offers the chance for immediate intraoperative revisions of endograft-related problems. Requiring only a single-phase acquisition, ceCBCT is associated with a considerable reduction in ED (50%–75%) compared to standard 3-phase MDCT angiography after EVAR. On the other hand, MDCT has a larger field of view and is associated with less radiation exposure for a single phase (reduction of 20%–60%) if only the stented region is covered; however, MDCT angiography also uses larger amounts of contrast.

Endovascular Management of Abdominal Aortic Aneurysms: the Year in Review

OPINION STATEMENT

Endovascular aneurysm repair (EVAR) has become the predominant method of treatment for abdominal aortic aneurysms (AAA). The use of conscious sedation with local anesthesia and percutaneous femoral access has further decreased the morbidity of the procedure. Current devices can more effectively manage increasingly "hostile" aneurysm necks, while chimney grafts or dedicated fenestrated stent-grafts can be used for juxta-renal disease with favorable results. However, endovascular repair does present a new set of challenges, and endoleaks remain an area of concern. While there is general consensus that type I and type III endoleaks require treatment, type II endoleaks are the topic of ongoing research and debate. Development of devices and techniques to prevent and treat endoleak continues to progress. Advances in contrast-enhanced ultrasound are reducing reliance on computed tomography for post-operative monitoring. This is an important step in this population at high risk for the development of kidney failure. Despite these many innovations, further research is needed to optimize the care of patients with AAA.

Contemporary Applications of Ultrasound in Abdominal Aortic Aneurysm Management

Ultrasound (US) is a well-established screening tool for detection of abdominal aortic aneurysms (AAAs) and is currently recommended not only for those with a relevant family history but also for all men and high-risk women older than 65 years of age. The advent of minimally invasive endovascular techniques in the treatment of AAAs [endovascular aneurysm repair (EVAR)] has increased the need for repeat imaging, especially in the postoperative period. Nevertheless, preoperative planning, intraoperative execution, and postoperative surveillance all mandate accurate imaging. While computed tomographic angiography and angiography have dominated the field, repeatedly exposing patients to the deleterious effects of cumulative radiation and intravenous nephrotoxic contrast, US technology has significantly evolved over the past decade. In addition to standard color duplex US, 2D, 3D, or 4D contrast-enhanced US modalities are revolutionizing AAA management and postoperative surveillance. This technology can accurately measure AAA diameter and volume, and most importantly, it can detect endoleaks post-EVAR with high sensitivity and specificity. 4D contrast-enhanced US can even provide hemodynamic information about the branch vessels following fenestrated EVARs. The need for experienced US operators and accredited vascular labs is mandatory to guarantee the reliability of the results. This review article presents a comprehensive overview of the literature on the state-of-art US imaging in AAA management, including post-EVAR follow-up, techniques, and diagnostic accuracy.

Intraoperative contrast-enhanced cone beam computed tomography to assess technical success during endovascular aneurysm repair

BACKGROUND

The aim of the study was to analyze the use of contrast-enhanced cone beam computed tomography (ceCBCT) during endovascular aneurysm repair (EVAR) and to compare this imaging modality with standard completion digital subtraction angiography (cDSA) and postoperative computed tomography angiography (CTA) regarding the detection of endograft-associated complications.

METHODS

Between September 2012 and April 2015, ceCBCT was used in 98 EVAR patients in addition to cDSA and CTA. Endoleaks, intraluminal thrombus and limb stenoses, contrast agent use, and radiation exposure were recorded for all modalities.

RESULTS

cDSA detected 16 (16.3%) endoleaks; ceCBCT, 35 (35.7%) endoleaks; and CTA, 22 (22.4%) endoleaks. All endoleaks identified by cDSA or CTA were also seen on ceCBCT. ceCBCT detected intraluminal thrombus in three patients (none in cDSA or CTA) and previously undetected limb stenoses in three patients. It prompted intraoperative interventions in 7 of 98 patients (7.1%). Replacing cDSA and CTA by ceCBCT would have caused a 39% reduction of in-hospital contrast agent volume in this cohort.

CONCLUSIONS

ceCBCT can reliably detect all endograft-associated complications during EVAR. It offers the chance for immediate revision of remediable problems in a relevant proportion of patients and could thus reduce early reintervention rates. ceCBCT can safely replace early follow-up CTA and thereby reduce in-hospital use of contrast media.

Modern diagnostics for type B aortic dissection

Background

Undifferentiated chest pain is one of the most common complaints in the acute care setting. Type B aortic dissection is an important cause of chest pain and a complex clinical entity, which carries significant morbidity and mortality and requires accurate clinical and radiological evaluation.

Methods

Imaging technologies have become an irreplaceable tool to establish the diagnosis of aortic dissection and to plan treatment strategies. Computed tomography is an important component in this process, replacing catheter-based angiography as the most commonly used preoperative and postoperative imaging modality for the thoracic aorta. The use of functional imaging methods, such as magnetic resonance imaging and echocardiography is evolving. These methods are able to provide the clinically relevant anatomical, hemodynamic and biomechanical information that is necessary for accurate diagnosis, risk stratification and patient selection for treatment.

Conclusion

Advanced image acquisition equipment and expertise are increasingly available in a growing number of institutions and as a consequence, existing strategies for the management of type B dissection are rapidly evolving.