Endovascular treatment of abdominal aortic aneurysm

Endovascular repair versus open repair in the treatment of ruptured aortic aneurysms: a systematic review

INTRODUCTION

Rupture of abdominal aortic aneurysm remains a fatal event in up to 65% of cases and emergency open surgery (ruptured open aneurysm repair or rOAR) has a great intraoperative mortality of about 30-50%. The introduction of endovascular repair of abdominal aortic aneurysm (ruptured endovascular aneurysm repair or rEVAR) has rapidly challenged the conventional approach to this catastrophic event. The purpose of this systematic review is to compare the outcomes of open surgical repair and endovascular interventions.

EVIDENCE ACQUISITION

A literature search was performed using Medline, Scopus, and Science Direct from August 2010 to March 2017 using keywords identified and agreed by the authors. Randomized trials, cohort studies, and case-report series were contemplated to give a breadth of clinical data.

EVIDENCE SYNTHESIS

Ninety-three studies were included in the final analysis. Thirty-five (50.7%) of the listed studies evaluating the within 30 days mortality rates deposed in favor of rEVAR, while the others (comprising all four included RCTs) failed detecting any difference. Late mortality rates were found to be lower in rEVAR group in seven on twenty-seven studies (25.9%), while one (3.7%) reported higher mortality rates following rEVAR performed before 2005, one found lower incidence of mortality at 6 months in the endovascular group but higher rates in the same population at 8 years of follow-up, and the remaining (66.7%) (including all three RCTs) failed finding any benefit of rEVAR on rOAR. A lower incidence of complications was reported by thirteen groups (46.4%), while other thirteen studies did not find any difference between rEVAR and rOAR. Each of these two conclusions was corroborated by one RCTs. Other two studies (7.2%) found higher rates of tracheostomies, myocardial infarction, and acute tubular necrosis or respiratory, urinary complications, and acute renal failure respectively in rOAR group. The majority of studies (59.0%, 72.7%, and 89.3%, respectively) and all RCTs found significantly lower rates of length of hospitalization, intensive care unit transfer, and blood loss with or without transfusion need in rEVAR group. The large majority of the studies did not specified neither the type nor the brands of employed stent grafts.

CONCLUSIONS

The bulk of evidence regarding the comparison between endovascular and open surgery approach to RAAA points to: 1) non-inferiority of rEVAR in terms of early (within 30 days) and late mortality as well as rate of complications and length of hospitalization, with trends of better outcomes associated to the endovascular approach; 2) significantly better outcomes in terms of intensive care unit transfer and blood loss with or without transfusion need in the rEVAR group. These conclusions reflect the results of the available RCTs included in the present review. Thus rEVAR can be considered a safe method in treating RAAA and we suggest that it should be preferred when technically feasible. However, more RCTs are needed in order to give strength of these evidences, bring to definite clinical recommendations regarding this subject, and assess the superiority (if present) of one or more brands of stent grafts over the others.

Consideration of Sex Differences in Design and Reporting of Experimental Arterial Pathology Studies-Statement From ATVB Council

There are many differences in arterial diseases between men and women, including prevalence, clinical manifestations, treatments, and prognosis. The new policy of the National Institutes of Health, which requires the inclusion of sex as a biological variable for preclinical studies, aims to foster new mechanistic insights and to enhance our understanding of sex differences in human diseases. The purpose of this statement is to suggest guidelines for designing and reporting sex as a biological variable in animal models of atherosclerosis, thoracic and abdominal aortic aneurysms, and peripheral arterial disease. We briefly review sex differences of these human diseases and their animal models, followed by suggestions on experimental design and reporting of animal studies for these vascular pathologies.

Endovascular treatment for ruptured abdominal aortic aneurysm

BACKGROUND

An abdominal aortic aneurysm (AAA) (pathological enlargement of the aorta) is a condition that can occur as a person ages. It is most commonly seen in men older than 65 years of age. Progressive aneurysm enlargement can lead to rupture and massive internal bleeding, which is fatal unless timely repair can be achieved. Despite improvements in perioperative care, mortality remains high (approximately 50%) after conventional open surgical repair. Endovascular aneurysm repair (EVAR), a minimally invasive technique, has been shown to reduce early morbidity and mortality as compared to conventional open surgery for planned AAA repair. More recently emergency endovascular aneurysm repair (eEVAR) has been used successfully to treat ruptured abdominal aortic aneurysm (RAAA), proving that it is feasible in select patients; however, it is unclear if eEVAR will lead to significant improvements in outcomes for these patients or if indeed it can replace conventional open repair as the preferred treatment for this lethal condition. This is an update of the review first published in 2006.

OBJECTIVES

To assess the advantages and disadvantages of emergency endovascular aneurysm repair (eEVAR) in comparison with conventional open surgical repair for the treatment of ruptured abdominal aortic aneurysm (RAAA). This will be determined by comparing the effects of eEVAR and conventional open surgical repair on short-term mortality, major complication rates, aneurysm exclusion (specifically endoleaks in the eEVAR treatment group), and late complications.

SEARCH METHODS

For this update the Cochrane Vascular Information Specialist searched the Cochrane Vascular Specialised Register (last searched June 2016), CENTRAL (2016, Issue 5), and trials registries. We also checked reference lists of relevant publications.

SELECTION CRITERIA

Randomised controlled trials in which participants with a clinically or radiologically diagnosed RAAA were randomly allocated to eEVAR or conventional open surgical repair.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed studies identified for potential inclusion for eligibility. Two review authors also independently completed data extraction and quality assessment. Disagreements were resolved through discussion. We performed meta-analysis using fixed-effect models with odds ratios (ORs) and 95% confidence intervals (CIs) for dichotomous data and mean differences with 95% CIs for continuous data.

MAIN RESULTS

We included four randomised controlled trials in this review. A total of 868 participants with a clinical or radiological diagnosis of RAAA were randomised to receive either eEVAR or open surgical repair. Overall risk of bias was low, but we considered one study that performed randomisation in blocks by week and performed no allocation concealment and no blinding to be at high risk of selection bias. Another study did not adequately report random sequence generation, putting it at risk of selection bias, and two studies were underpowered. There was no clear evidence to support a difference between the two interventions for 30-day (or in-hospital) mortality (OR 0.88, 95% CI 0.66 to 1.16; moderate-quality evidence). There were a total of 44 endoleak events in 128 participants from three studies (low-quality evidence). Thirty-day complication outcomes (myocardial infarction, stroke, composite cardiac complications, renal complications, severe bowel ischaemia, spinal cord ischaemia, reoperation, amputation, and respiratory failure) were reported in between one and three studies, therefore we were unable to draw a robust conclusion. We downgraded the quality of the evidence for myocardial infarction, renal complications, and respiratory failure due to imprecision, inconsistency, and risk of bias. Odds ratios for complications outcomes were OR 2.38 (95% CI 0.34 to 16.53; 139 participants; 2 studies; low-quality evidence) for myocardial infarction; OR 1.07 (95% CI 0.21 to 5.42; 255 participants; 3 studies; low-quality evidence) for renal complications; and OR 3.62 (95% CI 0.14 to 95.78; 32 participants; 1 study; low-quality evidence) for respiratory failure. There was low-quality evidence of a reduction in bowel ischaemia in the eEVAR treatment group, but very few events were reported (OR 0.37, 95% CI 0.14 to 0.94), and we downgraded the evidence due to imprecision and risk of bias. Six-month and one-year outcomes were evaluated in three studies, but only results from a single study could be used for each outcome, which showed no clear evidence of a difference between the interventions. We rated six-month mortality evidence as of moderate quality due to imprecision (OR 0.89, 95% CI 0.40 to 1.98; 116 participants).

AUTHORS' CONCLUSIONS

The conclusions of this review are currently limited by the paucity of data. We found from the data available moderate-quality evidence suggesting there is no difference in 30-day mortality between eEVAR and open repair. Not enough information was provided for complications for us to make a well-informed conclusion, although it is possible that eEVAR is associated with a reduction in bowel ischaemia. Long-term data were lacking for both survival and late complications. More high-quality randomised controlled trials comparing eEVAR and open repair for the treatment of RAAA are needed to better understand if one method is superior to the other, or if there is no difference between the methods on relevant outcomes.

Endovascular repair or open repair for ruptured abdominal aortic aneurysm: a Cochrane systematic review

OBJECTIVES

Emergency endovascular aneurysm repair (eEVAR) may improve outcomes for patients with ruptured abdominal aortic aneurysm (RAAA). The study aim was to compare the outcomes for eEVAR with conventional open surgical repair for the treatment of RAAA.

SETTING

A systematic review of relevant publications was performed. Randomised controlled trials (RCTs) comparing eEVAR with open surgical repair for RAAA were included.

PARTICIPANTS

3 RCTs were included, with a total of 761 patients with RAAA.

INTERVENTIONS

Meta-analysis was performed with fixed-effects models with ORs and 95% CIs for dichotomous data and mean differences with 95% CIs for continuous data.

PRIMARY AND SECONDARY OUTCOME MEASURES

Primary outcome was short-term mortality. Secondary outcome measures included aneurysm-specific and general complication rates, quality of life and economic analysis.

RESULTS

Overall risk of bias was low. There was no difference between the 2 interventions on 30-day (or in-hospital) mortality, OR 0.91 (95% CI 0.67 to 1.22; p=0.52). 30-day complications included myocardial infarction, stroke, composite cardiac complications, renal complications, severe bowel ischaemia, spinal cord ischaemia, reoperation, amputation and respiratory failure. Reporting was incomplete, and no robust conclusion was drawn. For complication outcomes that did include at least 2 studies in the meta-analysis, there was no clear evidence to support a difference between eEVAR and open repair. Longer term outcomes and cost per patient were evaluated in only a single study, thus precluding definite conclusions.

CONCLUSIONS

Outcomes between eEVAR and open repair, specifically 30-day mortality, are similar. However, further high-quality trials are required, as the paucity of data currently limits the conclusions.

Endovascular treatment for ruptured abdominal aortic aneurysm

BACKGROUND

An abdominal aortic aneurysm (AAA) (pathological enlargement of the aorta) can develop in both men and women as they grow older. It is most commonly seen in men over the age of 65 years. Progressive aneurysm enlargement can lead to rupture and massive internal bleeding, a fatal event unless timely repair can be achieved. Despite improvements in perioperative care, mortality remains high (approximately 50%) after conventional open surgical repair. A newer minimally invasive technique, endovascular aneurysm repair (EVAR), has been shown to reduce early morbidity and mortality as compared to conventional open surgery for planned AAA repair. Emergency endovascular aneurysm repair (eEVAR) has been used successfully to treat ruptured abdominal aortic aneurysm (RAAA), proving that it is feasible in selected patients. However, it is not yet known if eEVAR will lead to significant improvements in outcomes for these patients or indeed if it can replace conventional open repair as the preferred treatment for this lethal condition.

OBJECTIVES

To assess the advantages and disadvantages of emergency endovascular aneurysm repair (eEVAR) in comparison with conventional open surgical repair for the treatment of ruptured abdominal aortic aneurysm (RAAA). This will be determined by the effect on short-term mortality, major complication rates, aneurysm exclusion, and late complications when compared with the effects in patients who have had conventional open repair of RAAA.

SEARCH METHODS

For this update the Cochrane Peripheral Vascular Diseases Group Trials Search Co-ordinator searched the Specialised Register (last searched February 2014) and CENTRAL (2014, Issue 2). Reference lists of relevant publications were also checked.

SELECTION CRITERIA

Randomised controlled trials in which patients with a clinically or radiologically diagnosed RAAA were randomly allocated to eEVAR or conventional open surgical repair.

DATA COLLECTION AND ANALYSIS

Studies identified for potential inclusion were independently assessed for eligibility by at least two review authors. Data extraction and quality assessment were also completed independently by two review authors. Disagreements were resolved through discussion. Meta-analysis was performed using fixed-effect models with odds ratios (ORs) and 95% confidence intervals (CIs) for dichotomous data and mean differences with 95% CIs for continuous data.

MAIN RESULTS

Three randomised controlled trials were included in this review. A total of 761 patients with a clinical or radiological diagnosis of RAAA were randomised to receive either eEVAR or open surgical repair. Overall risk of bias was low but one study did not adequately report random sequence generation, putting it at risk of selection bias, two studies did not report on outcomes identified in their protocol, indicating reporting bias, and one study was underpowered. There was no clear evidence to support a difference between the two interventions on 30-day (or in-hospital) mortality, OR of 0.91 (95% CI 0.67 to 1.22; P = 0.52). The 30-day complications included myocardial infarction, stroke, composite cardiac complications, renal complications, severe bowel ischaemia, spinal cord ischaemia, re-operation, amputation, and respiratory failure. Individual complication outcomes were reported in only one or two studies and therefore no robust conclusion can currently be drawn. For complication outcomes that did include at least two studies in the meta-analysis there was no clear evidence to support a difference between eEVAR and open repair. Six-month outcomes were evaluated in only a single study, which included mortality and re-operation, with no clear evidence of a difference between the interventions and no overall association. Cost per patient was only evaluated in a single study and therefore no overall associations can currently be derived.

AUTHORS' CONCLUSIONS

The conclusions of this review are currently limited by the paucity of data. From the data available there is no difference in the outcomes evaluated in this review between eEVAR and open repair, specifically 30-day mortality. Not enough information was provided for complications in order to make a well informed conclusion at this time. Long-term data are lacking for both survival and late complications. More high quality, randomised controlled trials comparing eEVAR and open repair for the treatment of RAAA are needed in order to better understand if one method is superior to the other, or if there is no difference between the methods on relevant outcomes.

Comparison of endovascular and open repair of ruptured abdominal aortic aneurysm in the United States in the past decade

PURPOSE

The purpose of this study is national-level comparison of the endovascular (EVAR) and open repair (OAR) of ruptured abdominal aortic aneurysm (AAA) in the United States from 2001 to 2010.

METHODS

The data were obtained from nationwide inpatient sample from the Department of Health and Human Services. Ruptured AAA treated by OAR or EVAR were selected using combination ICD-9 codes.

RESULTS

There were 42,126 cases of ruptured AAA of which 8,140 (19.3%) were repaired by EVAR. EVAR patients were older (74.1 vs. 72.8 years, p < 0.001) and had higher incidence of comorbidities compared with OAR group. EVAR patients had lower in-hospital mortality (25.9 vs. 39.1%, p < 0.001) and shorter hospital stay (10.4 vs. 13.7 days, p < 0.001). More patients were discharged home following EVAR (36.8 vs. 21.5%, p < 0.001). There was reduced need for institutional rehabilitation following EVAR (26.3 vs. 29.1%, p < 0.001). Females had significantly higher mortality compared with males after both EVAR (32.2 vs. 24.1%, p < 0.001) and OAR (46.2 vs. 36.9%, p < 0.001). The hospital mortality (41.3-25.8%, p < 0.001) and mean length of stay (11.8-9.7 days, p < 0.01) of EVAR steadily improved over the study period.

CONCLUSIONS

National level comparison of data from the past decade shows that in suitable cases, EVAR for ruptured AAA is associated with reduced hospital mortality, shorter hospital stay, and reduced need for rehabilitation. EVAR outcomes showed consistent improvement with time. Regardless of the type of repair, women had higher mortality compared with men.

Nationwide trends in abdominal aortic aneurysm repair and use of endovascular repair in the emergency setting

PURPOSE

To analyze nationwide trends in abdominal aortic aneurysm (AAA) repair and the use of endovascular abdominal aortic aneurysm repair (EVAR) in the emergency setting.

MATERIALS AND METHODS

Data were obtained from the Nationwide Inpatient Sample (NIS) using the International Classification of Diseases, Ninth Revision-Clinical Modification (ICD-9-CM) codes for open and endovascular repairs from 2001-2009. Trends in outcome parameters and hospital charges were compared.

RESULTS

The number of emergency EVAR procedures increased from 382 in 2001 to 1,247 in 2009 (P < .001). During the study period, length of hospital stay associated with total number of EVAR procedures decreased from 3.8 days to 3.4 days (P < .05), and the in-hospital mortality decreased from 2.4% to 2% (P = .32). From 2001-2009, mean hospital charges associated with EVAR increased from $50,630 to $91,401 (74% increase), whereas charges associated with open repairs increased from $54,578 to $128,925 (136% increase). The proportion of patients needing rehabilitation or nursing home placement after EVAR increased from 5.8% to 7.7% (P < .01), and need for home health increased from 6.9% to 10.5% (P < .01).

CONCLUSIONS

There was a significant increase in the number of emergency EVAR procedures during the study period; however, the overall in-hospital mortality associated with EVAR remained unchanged, and the length of hospital stay showed a decreasing trend. The total hospital charges for EVAR were lower than the charges for open abdominal aneurysm repair throughout the study period; the difference in charges between the procedures showed a significant increasing trend with time.

Noninvasive vascular ultrasound elastography applied to the characterization of experimental aneurysms and follow-up after endovascular repair

Experimental and simulation studies were conducted to noninvasively characterize abdominal aneurysms with ultrasound (US) elastography before and after endovascular treatment. Twenty three dogs having bilateral aneurysms surgically created on iliac arteries with venous patches were investigated. In a first set of experiments, the feasibility of elastography to differentiate vascular wall elastic properties between the aneurismal neck (healthy region) and the venous patch (pathological region) was evaluated on six dogs. Lower strain values were found in venous patches (p < 0.001). In a second set of experiments, 17 dogs having endovascular repair (EVAR) by stent graft (SG) insertion were examined three months after SG implantation. Angiography, color Doppler US, examination of macroscopic sections and US elastography were used. The value of elastography was validated with the following end points by considering a solid thrombus of a healed aneurysm as a structure with small deformations and a soft thrombus associated with endoleaks as a more deformable tissue: (1) the correlation between the size of healed organized thrombi estimated by elastography and by macroscopic examinations; (2) the correlation between the strain amplitude measured within vessel wall elastograms and the leak size; and (3) agreement on the presence and size of endoleaks as determined by elastography and by combined reference imaging modalities (angiography + Doppler US). Mean surfaces of solid thrombi estimated with elastography were found correlated with those measured on macroscopic sections (r = 0.88, p < 0.001). Quantitative strain values measured within the vessel wall were poorly linked with the leak size (r = 0.12, p = 0.5). However, the qualitative evaluation of leak size in the aneurismal sac was very good, with a Kappa agreement coefficient of 0.79 between elastography and combined reference imaging modalities. In summary, complementing B-scan and color Doppler, noninvasive US elastography was found to be potentially a relevant tool for aneurismal follow-up after EVAR, provided it allows geometrical and mechanical characterizations of the solid thrombus within the aneurismal sac. This elasticity imaging technique might help detecting potential complications during follows-up subsequent to EVAR.

Sealing of type III endoleaks with ethylene vinyl alcohol copolymer in a canine model

PURPOSE

To test ethylene vinyl alcohol copolymer (EVOH) as a sealing agent for persistent abdominal aortic aneurysm (AAA) endograft leaks.

MATERIALS AND METHODS

Twelve dogs underwent creation of AAAs with a Palmaz P4014 stent. A 10-mm x 5-cm Wallgraft endoprosthesis with a 4-mm-diameter hole cut into its side was deployed within the AAA. One week later, computed tomography (CT) and angiography were performed and the aneurysm sac was catheterized through the 4-mm hole. Then, EVOH was injected into the sac and lumbar arteries. Four weeks thereafter, all surviving animals underwent repeat CT scanning and angiography and were then euthanized. The AAA underwent gross and microscopic study.

RESULTS

Three dogs died from aortic rupture within 24 hours of AAA creation and the remaining nine dogs survived to receive EVOH. All nine dogs had persistent flow into the sac and lumbar arteries at the time of EVOH delivery. Seven dogs survived to the end of the experiment, and all aneurysm sacs and lumbar arteries remained occluded on angiography and CT. Histologic examination revealed EVOH and thrombus admixed, with thrombus in varying stages of organization filling the aneurysm sac and lumbar arteries.

CONCLUSIONS

Embolization of type III endoleaks with EVOH proved to be feasible in a canine model. Further work is warranted to determine its therapeutic utility.

Treatment of type II endoleak with a transcatheter transcaval approach: results at 1-year follow-up

PURPOSE

This study assessed the feasibility and mid-term outcomes in the treatment of type II endoleak using transcatheter transcaval embolization (TTE).

METHODS

During an 8-month period, 12 patients underwent TTE. After direct transcaval puncture of the aneurysm sac, embolization was performed by injecting thrombin and placing coils. Systemic and intrasac pressures were recorded throughout the entire procedure. Computed tomography (CT) scans were performed at 24 hours, 30 days, 6 months, and 1 year after TTE to evaluate endoleaks and changes in sac diameter. Technical success was defined as the feasibility of the procedure; clinical success was defined as no evidence of leaks during the follow-up evaluation.

RESULTS

TTE was feasible in 11 of 12 patients (technical success 92%). The mean systemic pressure was 117 mm Hg. The mean intrasac pressure before embolization was 75 mm Hg (range, 39 to 125 mm Hg), 16.5 mm Hg (range, 7 to 40 mm Hg) in 10 patients after embolization, and it increased in one patient. CT scans at 24 hours showed stable contrast medium inside the sac in 10 patients. Only minor complications were observed during follow-up. At the 1-year follow-up, no recurrence of leaks was noted, and sac diameter was reduced in 10 of 11 patients. As a result, TTE clinical success was obtained in 10 (83%) of 12 patients.

CONCLUSION

TTE appears to be a feasible technique for the complete exclusion of type II endoleaks. Technical and clinical successes are comparable with other treatment strategies, and TTE should be considered an alternative to direct translumbar puncture of the aneurysm sac.

Endovascular abdominal aortic aneurysm repair

The operative mortality following conventional abdominal aortic aneurysm (AAA) repair has not fallen significantly over the past two decades. Since its inception in 1991, endovascular aneurysm repair (EVAR) has provided an alternative to open AAA repair and perhaps an opportunity to improve operative mortality. Two recent large randomised trials have demonstrated the short and medium term benefit of EVAR over open AAA repair, although data on the long term efficacy of the technique are still lacking. This review aimed at providing an overview of EVAR and a discussion of the potential benefits and current limitations of the technique.

Endovascular treatment for ruptured abdominal aortic aneurysm

BACKGROUND

An abdominal aortic aneurysm (AAA) (the pathological enlargement of the aorta) can develop in both men and women as they grow older. It is most commonly seen in men over the age of 65 years. Progressive aneurysm enlargement can lead to rupture and massive internal bleeding, a fatal event unless timely repair can be achieved. Despite improvements in perioperative care, mortality remains high (approximately 50%) after conventional open surgical repair. A newer minimally invasive technique, endovascular repair, has been shown to reduce early morbidity and mortality, as compared to conventional open surgery, for planned AAA repair. Emergency endovascular repair (eEVAR) has been used successfully to treat ruptured abdominal aortic aneurysm (RAAA), proving that it is feasible in selected patients. However, it is not yet known if eEVAR will lead to significant improvements in outcomes for these patients or indeed if it can replace conventional open repair as the preferred treatment for this lethal condition.

OBJECTIVES

To compare the advantages and disadvantages of eEVAR in comparison with conventional open surgical repair for the treatment of RAAA.

SEARCH STRATEGY

The Cochrane Peripheral Vascular Diseases Group searched their trials register (last searched October 2006) and the Cochrane Central Register of Controlled Trials (CENTRAL) database (last searched Issue 4, 2006). We searched a number of electronic databases and handsearched relevant journals until March 2006 to identify studies for inclusion.

SELECTION CRITERIA

Randomised controlled trials in which patients with a confirmed ruptured abdominal aortic aneurysm were randomly allocated to eEVAR, or conventional open surgical repair.

DATA COLLECTION AND ANALYSIS

Studies identified for potential inclusion were independently assessed for eligibility by at least two reviewers, with excluded studies further checked by the agreed arbitrators. As no randomised controlled trials were identified at present no tests of heterogeneity or sensitivity analysis were performed.

MAIN RESULTS

There were no randomised controlled trials identified at present comparing eEVAR with conventional open surgical repair for the treatment of RAAA.

AUTHORS' CONCLUSIONS

There is no high quality evidence to support the use of eEVAR in the treatment of RAAA. However, evidence from prospective controlled studies without randomisation, prospective studies, and retrospective case series suggest that eEVAR is feasible in selected patients, with outcomes comparable to best conventional open surgical repair for the treatment of RAAA . Furthermore, endovascular repair in selected patients may be associated with a trend towards reductions in blood loss, duration of intensive care treatment, and mortality.

HLA-DR expression on monocytes and systemic inflammation in patients with ruptured abdominal aortic aneurysms

Introduction

Mortality from ruptured abdominal aortic aneurysms (RAAA) remains high. Severe systemic inflammation, leading to multi-organ failure, often occurs in these patients. In this study we describe the level of HLA-DR expression in a consecutive group of patients following surgery for RAAA and compare results between survivors and non-survivors. A similar comparison is made for IL-6 and IL-10 levels and Sequential Organ Failure Assessment (SOFA) scores.

Methods

This is a prospective observational study. Patients with RAAA were prospectively analysed. Blood samples were collected on days 1, 3, 5, 7, 10 and 14. The fraction of CD-14 positive monocytes expressing HLA-DR was measured by flow-cytometry. IL-6 and IL-10 levels were measured by ELISA.

Results

The study included 30 patients with a median age of 70 years, of which 27 (90%) were men. Six patients died from multiple organ failure, all other patients survived. The SOFA scores were significantly higher in non-survivors on days 1 through 14. HLA-DR expression on monocytes was significantly lower on days 3, 5, 7, 10 and 14 in non-survivors. IL-6 and IL-10 levels were significantly higher in non-survivors on day 1 and days 1 and 3, respectively.

Conclusion

HLA-DR expression on monocytes was decreased, especially in non-survivors. All patients with RAAA displayed a severe inflammatory and anti-inflammatory response with an increased production of IL-6 and IL-10. Poor outcome is associated with high levels of IL-6 and IL-10 and a high SOFA score in the first three days after surgery, while low levels of HLA-DR expression are observed from day three after RAAA repair.

Effects of Wall Calcifications in Patient-Specific Wall Stress Analyses of Abdominal Aortic Aneurysms

It is generally acknowledged that rupture of an abdominal aortic aneurysm (AAA) occurs when the stress acting on the wall over the cardiac cycle exceeds the strength of the wall. Peak wall stress computations appear to give a more accurate rupture risk assessment than AAA diameter, which is currently used for a diagnose. Despite the numerous studies utilizing patient-specific wall stress modeling of AAAs, none investigated the effect of wall calcifications on wall stress. The objective of this study was to evaluate the influence of calcifications on patient-specific finite element stress computations. In addition, we assessed whether the effect of calcifications could be predicted directly from the CT-scans by relating the effect to the amount of calcification present in the AAA wall. For 6 AAAs, the location and extent of calcification was identified from CT-scans. A finite element model was created for each AAA and the areas of calcification were defined node-wise in the mesh of the model. Comparisons are made between maximum principal stress distributions, computed without calcifications and with calcifications with varying material properties. Peak stresses are determined from the stress results and related to a calcification index (CI), a quantification of the amount of calcification in the AAA wall. At calcification sites, local stresses increased, leading to a peak stress increase of 22% in the most severe case. Our results displayed a weak correlation between the CI and the increase in peak stress. Additionally, the results showed a marked influence of the calcification elastic modulus on computed stresses. Inclusion of calcifications in finite element analysis of AAAs resulted in a marked alteration of the stress distributions and should therefore be included in rupture risk assessment. The results also suggest that the location and shape of the calcified regions—not only the relative amount—are considerations that influence the effect on AAA wall stress. The dependency of the effect of the wall stress on the calcification elastic modulus points out the importance of determination of the material properties of calcified AAA wall.

Abdominal aortic aneurysm presenting as back pain to a chiropractic clinic: a case report

OBJECTIVE

The aim of this study was to discuss a patient with abdominal aortic aneurysm (AAA) who presented to a chiropractic teaching clinic and review the pathophysiology, therapeutic strategies, and complications associated with treatment of AAA.

CLINICAL FEATURES

A 69-year-old male patient experienced right-sided low back pain with radiation into the right leg for 3 weeks. The radiologic examination of the lumbar spine showed a 7.0-cm AAA and degenerative joint disease in the lumbar spine. Real-time ultrasonography showed an approximately 6.0-cm (transverse diameter), 4.1-cm (anteroposterior diameter), and approximately 7.0-cm (long) infrarenal AAA. Computed tomographic angiography showed additional bilateral iliac artery aneurysms.

INTERVENTION AND OUTCOME

This patient was treated with an endovascular stent graft repair of the abdominal aorta and bilateral iliac artery aneurysms. He has done well after surgery.

CONCLUSION

This article provides a case study and an overview of AAA. Rupture of an aortic aneurysm is preventable by cautious surveillance and the recognition of suspicious physical and radiographic findings in the population at risk. Early detection reduces mortality because repair is elective rather than emergent.

Treatment of type II endoleaks after endovascular repair of abdominal aortic aneurysms: transcaval approach

The purpose of the note is to describe a new technique for type II endoleak treatment, using an alternative approach through femoral venous access. Three patients who developed type II endoleak after endovascular repair of abdominal aortic aneurysm were treated with direct transcaval puncture and embolization inside the aneurysm sac. The detailed technique is described. All patients were treated without any complications and discharged 48 hours after the treatment. At 1 month follow-up the computed tomograph scan did not show a recurrence of a type II endoleak. The management of patients with type II endoleak is a controversial issue and different techniques have been proposed. We suggest an alternative technique for type II endoleak treatment. The feasibility and the advantages of this approach can offer new possibilities for the diagnosis as well as for the treatment of this complication.