Unmixing multi-spectral photoacoustic sources in human carotid plaques using non-negative independent component analysis.

Multi-spectral photoacoustic imaging (MSPAI) is promising for morphology assessment of carotid plaques; however, obtaining unique spectral characteristics of chromophores is cumbersome. We used MSPAI and non-negative independent component analysis (ICA) to unmix distinct signal sources in human carotid plaques blindly. The feasibility of the method was demonstrated on a plaque phantom with hemorrhage and cholesterol inclusions, and plaque endarterectomy samples ex vivo. Furthermore, the results were verified with histology using Masson's trichrome staining. Results showed that ICA could separate recent hemorrhages from old hemorrhages. Additionally, the signatures of cholesterol inclusion were also captured for the phantom experiment. Artifacts were successfully removed from signal sources. Histologic examinations showed high resemblance with the unmixed components and confirmed the morphologic distinction between recent and mature hemorrhages. In future pre-clinical studies, unmixing could be used for morphology assessment of intact human plaque samples.

[Neurogenic thoracic outlet syndrome]. / Neurogeen thoracic-outletsyndroom.

Neurogenic thoracic outlet syndrome (nTOS) is a type of thoracic outlet syndrome (TOS) where compression of the brachial plexus is responsible for development of upper-extremity, head and neck symptoms. We present a 16-year-old and a 34-year-old patient with nTOS. Diagnosis in both cases was done by following the recently published reporting standards for (n)TOS. After this multidisciplinary diagnostic work-up we performed a transaxillary thoracic outlet decompression (TOD). Due to lack of literature, difficult nomenclature and complexity of diagnosis and treatment, diagnosis of nTOS is often delayed. Recent experience shows that treatment of nTOS is safe and effective, both in the short term and the long term.

Patient Specific Wall Stress Analysis and Mechanical Characterization of Abdominal Aortic Aneurysms Using 4D Ultrasound.

OBJECTIVES: The aim of this study was to perform wall stress analysis (WSA) using 4D ultrasound (US) in 40 patients with an abdominal aortic aneurysm (AAA). The geometries and wall stress results were compared with computed tomography (CT) in seven patients. Additionally, the WSA models were calibrated using 4D motion estimation, resulting in patient specific material parameters that were compared among patients. METHODS: 4D-US images were acquired for 40 patients (AAA diameter 27-52 mm). Patient specific AAA geometries and wall motion were extracted from the 4D-US. WSA was performed and corresponding patient specific material properties were derived. For seven patients, CT data were available and analyzed for geometry and wall stress comparison. RESULTS: The 4D-US based 99th percentile wall stress ranged from 198 to 390 kPa. Regression analysis showed no significant relation between wall stress and diameter of the AAA. The similarity indices between US and CT were very good and ranged between 0.90 and 0.96, and the 25th, 50th, 75th, and 95th percentile wall stresses of the US and CT data were in agreement. The characterized patient specific shear modulus had a median of 1.1 MPa (interquartile range, 0.7-1.4 MPa). Based on the maximum AAA diameter, the AAAs were divided in a small, medium, and large diameter groups. The largest AAAs revealed an increased wall stiffness compared with the smallest AAAs. CONCLUSIONS: 4D ultrasound is applicable for wall stress analysis of AAAs, and offers the opportunity to perform wall stress analysis over time, also for AAAs who do not qualify for a CT or magnetic resonance imaging. Moreover, the patient specific material properties can be determined, which could possibly improve risk assessment.

Endovascular Treatment of Ruptured Abdominal Aortic Aneurysms with Hostile Aortic Neck Anatomy.

OBJECTIVE: To compare the mid-term results of endovascular aortic aneurysm repair (EVAR) for ruptured abdominal aortic aneurysms (RAAAs) in patients with favourable aortic neck anatomy (FNA) and hostile aortic neck anatomy (HNA). METHODS: Patients treated for a RAAA in a high volume endovascular centre in the Netherlands between February 2009 and January 2014 were identified retrospectively and divided into two groups based on aortic neck anatomy, FNA and HNA. HNA was defined as RAAA with a proximal neck of <10 mm, or a proximal neck of 10-15 mm with a suprarenal angulation (α) >45° and/or an infrarenal angulation (ß) >60°, or a proximal neck of >15 mm combined with α >60° and/or ß >75°. Patient demographics, procedure details, 30 day and 1 year outcomes were recorded. RESULTS: Of 39 included patients, 17 (44%) had HNA. Technical success was 100% for FNA and 88% for HNA (p = .184). There were no type IA endoleaks on completion angiography in either group; however, more adjunctive procedures were necessary for intra-operative type IA endoleaks in the HNA group (24% vs. 0%, p = .029). Thirty day mortality rates were comparable, FNA 14% vs. HNA 12% (p = 1.000). There were no statistically significant differences at 1 year follow up in type I endoleaks, secondary endovascular procedures, or all cause mortality. CONCLUSION: Emergency EVAR provides excellent results for treatment of RAAA patients with both FNA and HNA. EVAR in RAAAs with HNA is technically feasible and safe in experienced endovascular centres. Article history.

Beneficial Effects of Pre-operative Exercise Therapy in Patients with an Abdominal Aortic Aneurysm: A Systematic Review.

OBJECTIVE/BACKGROUND: The impact of post-operative complications in abdominal aortic aneurysm (AAA) surgery is substantial, and increases with age and concomitant co-morbidities. This systematic review focuses on the possible effects of pre-operative exercise therapy (PET) in patients with AAA on post-operative complications,aerobic capacity, physical fitness, and recovery. METHODS: A systematic search on PET prior to AAA surgery was conducted. The methodological quality of the included studies was rated using the Physiotherapy Evidence Database scale. The agreement between the reviewers was assessed with Cohen's kappa. RESULTS: Five studies were included, with a methodological quality ranging from moderate to good. Cohen's kappa was 0.79. Three studies focused on patients with an AAA (without indication for surgical repair) with physical fitness as the outcome measure. One study focused on PET in patients awaiting AAA surgery and one study focused on the effects of PET on post-operative complications, length of stay, and recovery. CONCLUSION: PET has beneficial effects on various physical fitness variables of patients with an AAA. Whether this leads to less complications or faster recovery remains unclear. In view of the large impact of post-operative complications, it is valuable to explore the possible benefits of a PET program in AAA surgery.

Rationale and design of the EAGLE Registry: EVAR with Endurant® in challenging anatomy.

AIM: The aim of this study was to collect clinical information on the performance of the Endurant® (II) Stent Graft System for endovascular repair in anatomically challenging infrarenal aneurysms, and to critically assess whether the current instructions for anatomic eligibility for endovascular treatment with this system are still applicable. METHODS: Initiated by doctors, EAGLE is a prospective, non-interventional study, aiming to enrol 250 patients in 20 experienced centres across several countries worldwide. EAGLE focuses on patients with challenging angulation or neck length. To minimize the risk of selection bias and enhance data quality, EAGLE eligibility will be determined by an independent core-lab and efforts will be made to secure consecutive enrolment of challenging cases. The EAGLE database is designed to merge with the on-going ENGAGE database, which enables comparative analysis of cases and results. RESULTS: The primary endpoint is treatment success at 30 days, 12 months and yearly up to 5 years postimplant. CONCLUSION: Separate studies on the performance of EVAR in challenging anatomy are necessary to demonstrate safety and effectiveness of the latest generation stent-grafts, which is essential in making a balanced judgment about the optimal management of AAAs.

Editor's choice--Use of disposable radiation-absorbing surgical drapes results in significant dose reduction during EVAR procedures.

OBJECTIVES: Because of the increasing number of interventional endovascular procedures with fluoroscopy and the corresponding high annual dose for interventionalists, additional dose-protecting measures are desirable. The purpose of this study was to evaluate the effect of disposable radiation-absorbing surgical drapes in reducing scatter radiation exposure for interventionalists and supporting staff during an endovascular aneurysm repair (EVAR) procedure. MATERIALS: This was a randomized control trial in which 36 EVAR procedures were randomized between execution with and without disposable radiation-absorbing surgical drapes (Radpad: Worldwide Innovations & Technologies, Inc., Kansas City, US, type 5511A). Dosimetric measurements were performed on the interventionalist (hand and chest) and theatre nurse (chest) with and without the use of the drapes to obtain the dose reduction and effect on the annual dose caused by the drapes. RESULTS: Use of disposable radiation-absorbing surgical drapes resulted in dose reductions of 49%, 55%, and 48%, respectively, measured on the hand and chest of the interventionalist and the chest of the theatre nurse. CONCLUSIONS: The use of disposable radiation-absorbing surgical drapes significantly reduces scatter radiation exposure for both the interventionalist and the supporting staff during EVAR procedures.

Standardized definitions and clinical endpoints in trials investigating endovascular repair of aortic dissections.

OBJECTIVES: Endovascular therapy is a rapidly expanding option for the treatment of patients with aortic dissection (AD) and various studies have been published. These trials, however, are often difficult to interpret and compare because they do not utilize uniform clinical endpoint definitions. METHODS: The DEFINE Group is a collaborative effort of an ad hoc multidisciplinary team from various specialties involved in AD therapy in Europe and the United States. DEFINE's goal was to arrive at a broad based consensus for baseline and endpoint definitions in trials for endovascular therapy of various vascular pathologies. In this project, which started in December 2006, the individual team members reviewed the existing pertinent literature. Following this, a series of telephone conferences and face-to-face meetings were held to agree upon definitions. Input was also obtained from regulatory (United States Food and Drug Administration) and industry (device manufacturers with an interest in peripheral endovascular revascularization) stakeholders, respectively. RESULTS: These efforts resulted in the present document containing proposed baseline and endpoint definitions for clinical and morphological outcomes. Although the consensus has inevitably included certain arbitrary consensus choices and compromises, adherence to these proposed standard definitions would provide consistency across future trials, thereby facilitating evaluation of clinical effectiveness and safety of various endovascular revascularization techniques. CONCLUSIONS: This current document is based on a broad based consensus involving relevant stakeholders from the medical community, industry and regulatory bodies. It is proposed that the consensus document may have value for study design of future clinical trials in endovascular AD therapy as well as for regulatory purposes.

Influence of gender on EVAR outcomes with new low-profile devices.

Women have not benefitted to the same extent as men of endovascular abdominal aortic repair (EVAR). Besides differences in hormones and the higher rate of undiagnosed cardiovascular disease, there are anatomical differences between men and women influencing the outcome of endovascular treatment of abdominal aortic aneurysms (AAA). After the first decade of EVAR procedures, only 28% of women with an elective AAA were treated by EVAR due to their poor anatomical suitability for this technique. The anatomical challenges and their associated poorer outcomes suggest the need for advances in device design to better meet the specific female aneurysm anatomy and physiology. Most of the newer-generation endografts have been associated with lower incidences of graft occlusion compared with first-generation endografts, and might be more suitable for women. It is encouraging that EVAR has decreased long-term mortality in women and that women's survival begins to equal men's after 2 years. However, detailed, adjusted anatomical data from population-based samples are needed for better understanding of the differences in AAA anatomy and EVAR eligibility. This information will contribute to enhance the design, testing and evaluation of future stent grafts, to ensure that women will benefit from EVAR to the same extent as men.

Challenging the evidence for pre-emptive coil embolisation of the internal iliac artery during endovascular aneurysm repair.

OBJECTIVES: We retrospectively analysed the results of a strategy in which coverage of the internal iliac artery (IIA) during endovascular aneurysm repair (EVAR) was routinely performed without coil embolisation. METHODS: From January 2010 until May 2012, 32 patients (96.9% men; mean age 73.0 years, range 52-89 years) underwent EVAR with stent grafts extended into the external iliac artery (EIA), all without prior coil embolisation. Aneurysm morphology was determined on preoperative computed tomography (CT) images. During follow-up, patients were interviewed about buttock claudication, and the occurrence of endoleaks and evolution of aneurysm diameter were recorded. RESULTS: At baseline, the mid-common iliac artery (CIA) diameter was 33.5 ± 16.8 mm and seven patients presented with ruptured aneurysms. Mean follow-up was 14.3 ± 7.4 months. There were eight deaths, none related to IIA coverage. Buttock claudication occurred in seven (22.6%) patients, which persisted after 6 months in two cases of bilateral IIA coverage. No Type-I or -II endoleaks occurred related to IIA coverage. Aneurysm growth was not observed. CONCLUSION: Endovascular treatment of aortoiliac and iliac aneurysm without pre-emptive coil embolisation of the IIA appears safe and effective. No IIA-related endoleaks or re-interventions occurred in our series. This approach saves operating time, contrast load and costs and may reduce complications. However, a larger population and longer follow-up is required to confirm our findings.

EVAR reintervention management strategies in contemporary practice.

It is known that following an endovascular aneurysm repair (EVAR) procedure, patients may experience endoleaks, device migration, stent fractures, graft deterioration, or aneurysm growth that might require a reintervention. In this review management strategies of reinterventions after EVAR in contemporary practice will be discussed. The current endovascular treatment options of Type I endoleak involve securing of the attachment site with percutaneous transluminal balloon angioplasty, stent-graft extension, or placement of a stent at the proximal attachment site. Moreover, the use of endostaples to secure the position of the proximal cuff to the primary endograft have been developed. Type II endoleaks can be managed conservatively if the aneurysm is shrinking or remains stable. Otherwise, reinterventions include transarterial embolization, translumbar embolization, transcaval embolization, direct thrombin injection, and endoscopic or open ligation of the lumbar and mesenteric arteries. There is little debate regarding the treatment of type III endoleaks, including deployement of additional stent graft components to bridge the defect. Endovascular treatment of endotension includes endovascular conversion stent or relining of the stent graft. Alternative options are puncture of the aneurysm sac and removal of the aneurysm sac content. In case of migration large balloon-expandable stents can be used to improve the seal between the components, or devices that deploy staples to secure endovascular grafts to the aortic wall to secure endovascular components together. In conclusion, the first treatment options for reinterventions after EVAR are catheter based nowadays.

Early results from the ENGAGE registry: real-world performance of the Endurant Stent Graft for endovascular AAA repair in 1262 patients.

OBJECTIVE: The ENGAGE registry was undertaken to examine the real-world outcome after endovascular abdominal aortic aneurysm (AAA) repair (EVAR) with the Endurant Stent Graft in a large, contemporary, global series of patients. METHODS: From March 2009 to April 2011, 1262 AAA patients (89.6% men; mean age 73.1 years, range 43-93 years) were enrolled from 79 sites in 30 countries and treated with Endurant. Results are described following the reporting standards for EVAR. Follow-up data were tabulated for all 1262 patients at a 30-day follow-up and for the first 500 patients at a 1-year follow-up. RESULTS: Intra-operative technical success was achieved in 99.0% of cases. Within 30 days, adverse events were reported in 3.9% of patients, including a 1.3% mortality rate. Type-I or -III endoleaks were identified in 1.5% of cases. Estimated overall survival, aneurysm-related survival and freedom from secondary interventions at 1 year were 91.6%, 98.6% and 95.1%, respectively. At 1 year, aneurysm size increased ≥ 5 mm in 2.8% and decreased ≥ 5 mm in 41.3% of cases. CONCLUSION: Early results from this real world, global experience are promising and indicate that endovascular AAA repair with the Endurant Stent Graft is safe and effective across different geographies and standards of practice. Longer-term follow-up is necessary to assess durability of these results.

Treatment of post-implantation aneurysm growth by laparoscopic sac fenestration: long-term results.

OBJECTIVES: Sac growth after endovascular aneurysm repair (EVAR) is an important finding, which may influence prognosis. In case of a type II endoleak or endotension, clipping of side branches and subsequent sac fenestration has been presented as a therapeutic alternative. The long-term clinical efficacy of this procedure is unknown. METHODS: The study included eight patients who underwent laparoscopic aortic collateral clipping and sac fenestration for enlarging aneurysms following EVAR. Secondary interventions and clinical outcome were retrieved from hospital records. Sac behaviour was evaluated measuring volumes on periodical computed tomography angiography (CTA) imaging using dedicated software. RESULTS: Follow-up had a median length of 6.6 (range 0.6-8.6) years. During this time, only three patients successfully achieved durable aneurysm shrinkage (n = 2) or stability (n = 1). The remaining patients suffered persistent (n = 2) or recurrent sac growth (n = 3), all regarded as failure of fenestration. A total of six additional interventions were performed, comprising open conversion (n = 2), relining (n = 1) and implantation of iliac extensions (n = 3). All additional interventions were successful at arresting further sac growth during the remainder of follow-up. CONCLUSIONS: Despite being a less invasive alternative to conversion and open repair, the long-term outcome of sac fenestration is unpredictable and additional major procedures were often necessary to arrest sac growth.

No differences in perioperative outcome between symptomatic and asymptomatic AAAs after EVAR: an analysis from the ENGAGE Registry.

AIM: This study aimed to compare the differences in perioperative outcome after endovascular repair of symptomatic abdominal aneurysms (S-AAAs) and elective non-symptomatic AAAs (E-AAAs). Data from the ENGAGE Registry were used for the analysis. METHODS: Between March 2009 and December 2010, 1200 AAA patients were enrolled from 79 sites in 30 countries and treated with an Endurant Stent Graft. S-AAAs defined as AAAs accompanied by abdominal or back pain, without rupture, were present in 185 (15.4%) patients and E-AAAs in 1015 (84.6%) patients. Multivariate logistic regression was used to compare results. RESULTS: At baseline, E-AAA patients had larger aneurysms on average (P = 0.006) and scored higher ASA classification more often (P = 0.001). Further analyses were corrected for baseline differences. Operation time and technical success were comparable, and S-AAAs were admitted to the Intensive Care Unit (ICU) as often as E-AAAs (35.7% vs. 33.4%, P = 0.479). Post-operative hospitalisation was similar (4.83 ± 5.29 in E-AAAs and 4.37 ± 3.49 in S-AAAs, P = 0.360). No differences in the occurrence of major adverse events, including mortality, within the 30-day post-implantation were seen between S-AAA and E-AAA patients, respectively, 3.2% and 4.2% (P = 0.572). CONCLUSION: With contemporary devices and technical proficiency, there is no difference in outcome between symptomatic AAA and elective non-symptomatic AAA patients if treated with endovascular techniques.

Systematic approach to ruptured abdominal aortic aneurysm in the endovascular era: Intention-to-treat eEVAR protocol.

Emergency endovascular aneurysm repair (eEVAR) for ruptured abdominal aortic aneurysms (rAAA) is still a relatively new treatment option. A pre-defined strategy of an eEVAR first approach for rAAA is associated with improved mortality rates. After establishing and implementing the Intention-to-treat eEVAR protocol for rAAAs the mortality and morbidity rates improved significantly. The presented Intention-to-treat eEVAR protocol starts at the first telephone call to the ambulance department and lasts until the post-operative care unit. The protocol involves the close collaboration between the ambulance department, vascular surgeon, emergency department physicians, anaesthesiologists, operating room staff and, radiology technicians. The availability of a variety of off-the-shelf stent-grafts, and an operating room that is adequately equipped to perform endovascular procedures is crucial in obtaining better outcomes. High volume centres that offer open surgical repair as well as eEVAR for rAAA show that the Intention-to-treat eEVAR protocol is achievable and appears to be associated with favorable mortality over open repair with appropriate case selection. Unstable or older patients with rAAA may particularly benefit by eEVAR.

The impact of gender on prognosis after non-cardiac vascular surgery.

OBJECTIVES: The objective was to evaluate the impact of gender on long-term survival of patients who underwent non-cardiac vascular surgery. DESIGN, MATERIAL AND METHODS: Our prospectively collected data contained information on 560 patients undergoing carotid endarterectomy (CEA), 923 elective abdominal aortic aneurysm repairs (AAA) and 1046 lower limb reconstructions (LLR). Patient characteristics and long-term mortality of women were compared to that of men. Kaplan-Meier (KM) survival curves were constructed for men and women, on which we superimposed age- and sex-matched KM survival curves of the general population. Cox proportional hazards regression was used to identify risk factors for mortality. RESULTS: Men in the CEA group had statistically significant higher all-cause mortality, hazard rate ratio (HRR) 1.41 (95% CI 1.01-1.98) No differences in mortality between the genders were observed in the AAA and LLR groups. Overall, men had more co-morbidities but received more disease-specific medication compared to women. Women retained their higher life expectancy after CEA but lost it in the AAA and LLR groups. CONCLUSION: Women retain their higher life expectancy after CEA; however, after AAA repair and LLR, this advantage is lost. Both men and women received too little disease-specific medication, but women were worse off.

Endovascular abdominal aortic aneurysm repair in women.

The objective of this review is to establish the role of endovascular aortic aneurysm repair (EVAR) in women. A step by step approach is taken looking at sex and gender differences in epidemiology, pathogenesis and natural history. We then proceed to discuss the results from the three randomized controlled trials comparing EVAR to open repair. Finally, sex-specific secondary prevention, risk factor management and medication, is discussed. Women seem to have higher mortality and more complications after EVAR. Risk factors such as diabetes and hypertension are associated with worse outcome in women compared to men. The role of EVAR in women is poorly investigated and its definite role remains to be determined. Aggressive treatment of risk factors and the optimisation of medication in women are indicated and deserve more attention in clinical practice and future research.

EVAR suitability is not a predictor for early and midterm mortality after open ruptured AAA repair.

OBJECTIVE: The reported mortality reduction of emergency endovascular aneurysm repair (eEVAR) compared with open repair in patients with a ruptured abdominal aortic aneurysm (rAAA), as observed in observational studies, might be flawed by selection bias based on anatomical suitability for eEVAR. In the present study, we compared mortality in EVAR suitable versus non-EVAR-suitable patients with a ruptured AAA who were all treated with conventional open repair. MATERIALS AND METHODS: In all patients presenting with a suspected rAAA, computed tomography angiography (CTA) scanning was performed. All consecutive patients with a confirmed rAAA on preoperative CTA scan and treated with open repair between April 2002 and April 2008 were included. Anatomical suitability for eEVAR was determined by two blinded independent reviewers. Outcomes evaluated were mortality (intra-operative, 30-day, and 6-month), morbidity, complications requiring re-intervention and length of hospital stay. RESULTS: A total of 107 consecutive patients presented with a rAAA and underwent preoperative CTA scanning. In 25 patients, eEVAR was performed. In the 82 patients who underwent open repair, CTA showed an EVAR-suitable rAAA in 33 patients (41.8%) and a non-EVAR-suitable rAAA in 49 patients. Thirty-day and 6-month mortality rate was 15/33 (45.5%; 95% confidence interval (CI) 28.1-63.7) and 18/33 (54.5%; 95% CI 36.4-71.9) in the EVAR-suitable group versus 24/49 (49.0%; 95% CI 34.4-63.7) (P=0.75) and 29/49 (59.2%; 95% CI 44.2-73.0) (P=0.68) in the non-EVAR-suitable group, respectively. CONCLUSIONS: The present study suggests that anatomical suitability for EVAR is not associated with lower early and midterm mortality in patients treated with open ruptured AAA repair. Therefore, the reported reduction in mortality between eEVAR and open repair is unlikely due to selection bias based on anatomical AAA configuration.