Characterizing Tissue Remodeling and Mechanical Heterogeneity in Cerebral Aneurysms

Accurately assessing the complex tissue mechanics of cerebral aneurysms (CAs) is critical for elucidating how CAs grow and whether that growth will lead to rupture. The factors that have been implicated in CA progression - blood flow dynamics, immune infiltration, and extracellular matrix remodeling - all occur heterogeneously throughout the CA. Thus, it stands to reason that the mechanical properties of CAs are also spatially heterogeneous. Here, we present a new method for characterizing the mechanical heterogeneity of human CAs using generalized anisotropic inverse mechanics, which uses biaxial stretching experiments and inverse analyses to determine the local Kelvin moduli and principal alignments within the tissue. Using this approach, we find that there is significant mechanical heterogeneity within a single acquired human CA. These results were confirmed using second harmonic generation imaging of the CA's fiber architecture and a correlation was observed. This approach provides a single-step method for determining the complex heterogeneous mechanics of CAs, which has important implications for future identification of metrics that can improve accuracy in prediction risk of rupture.

Wall stress analyses in patients with ≥5 cm versus <5 cm ascending thoracic aortic aneurysm

OBJECTIVE

Current guidelines for elective surgery of ascending thoracic aortic aneurysms (aTAAs) use aneurysm size as primary determinant for risk stratification of adverse events. Biomechanically, dissection may occur when wall stress exceeds wall strength. Determining patient-specific aTAA wall stresses by finite element analysis can potentially predict patient-specific risk of dissection. This study compared peak wall stresses in patients with ≥5.0 cm versus <5.0 cm aTAAs to determine correlation between diameter and wall stress.

METHODS

Patients with aTAA ≥5.0 cm (n = 47) and <5.0 cm (n = 53) were studied. Patient-specific aneurysm geometries obtained from echocardiogram-gated computed tomography were meshed and prestress geometries determined. Peak wall stresses and stress distributions were determined using LS-DYNA finite element analysis software (LSTC Inc, Livermore, Calif), with user-defined fiber-embedded material models under systolic pressure.

RESULTS

Peak circumferential stresses at systolic pressure were 530 ± 83 kPa for aTAA ≥5.0 cm versus 486 ± 87 kPa for aTAA <5.0 cm (P = .07), whereas peak longitudinal stresses were 331 ± 57 kPa versus 310 ± 54 kPa (P = .08), respectively. For aTAA ≥5.0 cm, correlation between peak circumferential stresses and size was 0.41, whereas correlation between peak longitudinal wall stresses and size was 0.33. However, for aTAA <5.0 cm, correlation between peak circumferential stresses and size was 0.23, whereas correlation between peak longitudinal stresses and size was 0.14.

CONCLUSIONS

Peak patient-specific aTAA wall stresses overall were larger for ≥5.0 cm than aTAA <5.0 cm. Although some correlation between size and peak wall stresses was found in aTAA ≥5.0 cm, poor correlation existed between size and peak wall stresses in aTAA <5.0 cm. Patient-specific wall stresses are particularly important in determining patient-specific risk of dissection for aTAA <5.0 cm.

Biomechanical Analysis of Cadaveric Thoracic Aorta Zones: The Isthmus is the Weakest Region

BACKGROUND

The thoracic aorta is a site of multiple pathological processes, such as aneurysms and dissections. When considering the development of endovascular devices, this vessel has been extensively manipulated because of aortic diseases, as well as to serve as a route for procedures involving the head and neck vessels. Therefore, the aim of the present study was to obtain biomechanical experimental information about the strength and deformability of this vessel.

MATERIALS AND METHODS

Thirty-one thoracic aorta specimens were harvested during the autopsy procedure. They were carefully dissected and transversally sectioned according to Criado's aortic arch map landing zones (0 to 4). The supra-aortic trunks were removed, and the aortic rings were opened in their convexity, which resulted in flat tissue segments. Four millimeter-wide strips were prepared from each zone after which they were attached to a clip system connected to the INSTRON SPEC 2200 device, which was responsible for pulling the fragment up to its rupture during the uniaxial tension test. The INSPEC software was used to coordinate the test, and data management was conducted via the SERIES IX software. The biomechanical variables that were measured included failure stress, failure tension, and failure strain.

RESULTS

When comparing the five segments from all 31 aortas, three different strength levels were observed. Zones 0 and 1 exhibited the highest failure stress and failure tension values, followed by Zones 2 and 4. Zone 3 (aortic isthmus) was the weakest segment that was tested when compared to the stress and tension of Zones 0 and 1 (P < 0.001), the stress and tension of Zone 2 (P = 0.005 and P = 0.002, respectively) and the stress and tension of Zone 4 (P = 0.023 and P = 0.006, respectively). Among donors > 65 years-old, women presented significantly weaker descending aortas than men in regards to stress (P = 0.049) and tension (P = 0.014). Among male donors, the elderly donors presented significantly stiffer aortic walls and weaker ascending (P = 0.029 for stress) and descending (P = 0.004 for stress; P = 0.031 for tension) aortas than younger men.

CONCLUSIONS

Uniaxial tensile strength tests revealed that the thoracic aorta is a very heterogeneous vessel. Isthmus frailty may add to the understanding of the pathophysiology of some aortic diseases that commonly compromise this region. The lower strength that was verifiedin some aortic segments from elderly donors may contribute to the genesis of some thoracic aorta diseases among that group of donors. These data can contribute to the development of new endovascular devices that are specifically designed for this vessel.

Comparison of peak wall stress and peak wall rupture index in ruptured and asymptomatic intact abdominal aortic aneurysms

BACKGROUND

Previous studies have suggested that finite element analysis (FEA) can estimate the rupture risk of an abdominal aortic aneurysm (AAA); however, the value of biomechanical estimates over measurement of AAA diameter alone remains unclear. This study aimed to compare peak wall stress (PWS) and peak wall rupture index (PWRI) in participants with ruptured and asymptomatic intact AAAs.

METHODS

The reproducibility of semiautomated methods for estimating aortic PWS and PWRI from CT images was assessed. PWS and PWRI were estimated in people with ruptured AAAs and those with asymptomatic intact AAAs matched by orthogonal diameter on a 1 : 2 basis. Spearman's correlation coefficient was used to assess the association between PWS or PWRI and AAA diameter. Independent associations between PWS or PWRI and AAA rupture were identified by means of logistic regression analyses.

RESULTS

Twenty individuals were included in the analysis of reproducibility. The main analysis included 50 patients with an intact AAA and 25 with a ruptured AAA. Median orthogonal diameter was similar in ruptured and intact AAAs (82·3 (i.q.r. 73·5-92·0) versus 81·0 (73·2-92·4) mm respectively; P = 0·906). Median PWS values were 286·8 (220·2-329·6) and 245·8 (215·2-302·3) kPa respectively (P = 0·192). There was no significant difference in PWRI between the two groups (P = 0·982). PWS and PWRI correlated positively with orthogonal diameter (both P < 0·001). Participants with high PWS, but not PWRI, were more likely to have a ruptured AAA after adjusting for potential confounders (odds ratio 5·84, 95 per cent c.i. 1·22 to 27·95; P = 0·027). This association was not maintained in all sensitivity analyses.

CONCLUSION

High aortic PWS had an inconsistent association with greater odds of aneurysm rupture in patients with a large AAA.

Mechanical role of intraluminal thrombus in aneurysm growth: A computational study

Models that seek to improve our current understanding of biochemical processes and predict disease progression have been increasingly in use over the last decades. Recently, we proposed a finite element implementation of arterial wall growth and remodeling with application to abdominal aortic aneurysms (AAAs). The study focused on changes within the aortic wall and did not include the complex role of intraluminal thrombus (ILT) during the AAA evolution. Thus, in this work, we extend the model with a gradual deposition of ILT and its mechanical influence on AAA growth. Despite neglecting the increased biochemical activity due to the presence of a proteolytically active luminal layer of ILT, and thus underestimating rupture risk potential, we show that ILT helps to slow down the growth of the aneurysm in the axial direction by redirecting blood pressure loading from the axial-radial plane to predominately radial direction. This very likely lowers rupture potential. We also show that the ratio of ILT volume to volume sac is an important factor in AAA stabilization and that fully thrombosed aneurysms could stabilize quicker and at smaller maximum diameters compared to partially thrombosed ones. Furthermore, we show that ILT formation and the associated mural stress decrease negatively impact the wall constituent production and thickness. Although further studies that include increased biochemical degradation of the wall after the formation of ILT and ILT deposition based on hemodynamics are needed, the present findings highlight the dual role an ILT plays during AAA progression.

Systematic Review and Meta-Analysis of Peak Wall Stress and Peak Wall Rupture Index in Ruptured and Asymptomatic Intact Abdominal Aortic Aneurysms

Background Prior studies have suggested aortic peak wall stress (PWS) and peak wall rupture index (PWRI) can estimate the rupture risk of an abdominal aortic aneurysm (AAA), but whether these measurements have independent predictive ability over assessing AAA diameter alone is unclear. The aim of this systematic review was to compare PWS and PWRI in participants with ruptured and asymptomatic intact AAAs of similar diameter. Methods and Results Web of Science, Scopus, Medline, and The Cochrane Library were systematically searched to identify studies assessing PWS and PWRI in ruptured and asymptomatic intact AAAs of similar diameter. Random-effects meta-analyses were performed using inverse variance-weighted methods. Leave-one-out sensitivity analyses were conducted to assess the robustness of findings. Risk of bias was assessed using a modification of the Newcastle-Ottawa scale and standard quality assessment criteria for evaluating primary research papers. Seven case-control studies involving 309 participants were included. Meta-analyses suggested that PWRI (standardized mean difference, 0.42; 95% CI, 0.14-0.70; P=0.004) but not PWS (standardized mean difference, 0.13; 95% CI, -0.18 to 0.44; P=0.418) was greater in ruptured than intact AAAs. Sensitivity analyses suggested that the findings were not dependent on the inclusion of any single study. The included studies were assessed to have a medium to high risk of bias. Conclusions Based on limited evidence, this study suggested that PWRI, but not PWS, is greater in ruptured than asymptomatic intact AAAs of similar maximum aortic diameter.

Reasons for and Outcomes of Open Abdominal Aortic Repair in the Endovascular Era

BACKGROUND

Endovascular aortic aneurysm repair (EVAR) has become the treatment of choice for most patients with abdominal aortic aneurysm (AAA). Open aneurysm repair (OAR) is still being used in a number of patients for specific reasons. The aim of the present study was to investigate the reasons and perioperative outcomes of OAR in a high-volume endovascular center.

METHODS

All patients who underwent OAR in a single center institution during the period April 2010 to July 2019 were retrospectively analyzed.

RESULTS

During the study period, 222 patients underwent OAR. One hundred and forty-one (63.5%) patients underwent elective surgery, and eighty-one (36.5%) patients were treated acutely. The reasons for the decision to perform OAR instead of EVAR were as follows: anatomical in 89 (40.1%) cases, rupture in unstable patient in 57 (25.7%) cases, AAA with concomitant iliac arterial occlusive disease in 44 (19.8%) cases, previous EVAR with complications in 14 (6.3%) cases, large pararenal aneurysm considered risky to wait for a customized fenestrated stent graft in 7 (3.2%) cases, young patient age in 4 (1.8%) cases, the patient's preference in 3 (1.4%) cases, infected/mycotic AAA in 2 (0.9%) cases, and simultaneous OAR with colon cancer resection (n = 1, 0.5%) and renal transplantation (n = 1, n = 0.5). Thirty-day mortality in elective cases was 5% (7/141) and in acute cases 34.6% (28/81).

CONCLUSIONS

This study shows that OAR is still used for selected patients despite improvements in EVAR technology. The most common reason for OAR was an unsuitable anatomy for EVAR. Perioperative mortality of OAR both for acute and elective cases as observed in this study is in line with published outcomes of other centers.

Inherited Thoracic Aortic Disease: New Insights and Translational Targets

Inherited thoracic aortopathies denote a group of congenital conditions that predispose to disease of the thoracic aorta. Aortic wall weakness and abnormal aortic hemodynamic profiles predispose these patients to dilatation of the thoracic aorta, which is generally silent but can precipitate aortic dissection or rupture with devastating and often fatal consequences. Current strategies to assess the future risk of aortic dissection or rupture are based primarily on monitoring aortic diameter. However, diameter alone is a poor predictor of risk, with many patients experiencing dissection or rupture below current intervention thresholds. Developing tools that improve the risk assessment of those with aortopathy is internationally regarded as a research priority. A robust understanding of the molecular pathways that lead to aortic wall weakness is required to identify biomarkers and therapeutic targets that could improve patient management. Here, we summarize the current understanding of the genetically determined mechanisms underlying inherited aortopathies and critically appraise the available blood biomarkers, imaging techniques, and therapeutic targets that have shown promise for improving the management of patients with these important and potentially fatal conditions.

Biomechanics of aortic wall failure with a focus on dissection and aneurysm: A review

Aortic dissections and aortic aneurysms are fatal events characterized by structural changes to the aortic wall. The maximum diameter criterion, typically used for aneurysm rupture risk estimations, has been challenged by more sophisticated biomechanically motivated models in the past. Although these models are very helpful for the clinicians in decision-making, they do not attempt to capture material failure. Following a short overview of the microstructure of the aorta, we analyze the failure mechanisms involved in the dissection and rupture by considering also traumatic rupture. We continue with a literature review of experimental studies relevant to quantify tissue strength. More specifically, we summarize more extensively uniaxial tensile, bulge inflation and peeling tests, and we also specify trouser, direct tension and in-plane shear tests. Finally we analyze biomechanically motivated models to predict rupture risk. Based on the findings of the reviewed studies and the rather large variations in tissue strength, we propose that an appropriate material failure criterion for aortic tissues should also reflect the microstructure in order to be effective. STATEMENT OF SIGNIFICANCE: Aortic dissections and aortic aneurysms are fatal events characterized by structural changes to the aortic wall. Despite the advances in medical, biomedical and biomechanical research, the mortality rates of aneurysms and dissections remain high. The present review article summarizes experimental studies that quantify the aortic wall strength and it discusses biomechanically motivated models to predict rupture risk. We identified contradictory observations and a large variation within and between data sets, which may be due to biological variations, different sample sizes, differences in experimental protocols, etc. Based on the findings of the reviewed literature and the rather large variations in tissue strength, it is proposed that an appropriate criterion for aortic failure should also reflect the microstructure.

Simulation training streamlines the real-life performance in endovascular repair of ruptured abdominal aortic aneurysms

OBJECTIVE

Difficulties in distributing endovascular experience among all operating room (OR) personnel prevented full-scale use of endovascular aneurysm repair (EVAR) in emergencies. To streamline the procedure of EVAR for ruptured aneurysm (rEVAR) and to provide this method even to unstable patients, we initiated regular simulation training sessions.

METHODS

This is an observational study of 29 simulation sessions performed between January 2015 and December 2017. We analyzed the development of time from OR door to aortic balloon occlusion during simulations and OR door to needle times in real-life rEVARs as well as the outcome of the 185 ruptured abdominal aortic aneurysm (rAAA) patients who arrived at the university hospital between January 2013 and December 2017. A questionnaire was sent for simulation attendants before and after the simulation session.

RESULTS

In the first simulations, the door to occlusion time was 20 to 35 minutes. After adding a hemodynamic collapse to the simulation protocol, the time decreased to 10 to 13 minutes in the 10 recent simulations, including a 5-minute cardiopulmonary resuscitation (P = .01). The electronic questionnaire performed for attendees before and after the simulation session showed significant improvement in both confidence and knowledge of the OR staff regarding rEVAR procedure. In the real-life rEVARs, 75 of the 185 patients with rAAAs underwent EVAR. Among rEVAR patients, the median OR door to needle time was 65 minutes before and 16 minutes after the onset of simulations (P = .000). The overall 30-day mortality among all rAAA patients was 44.8% and 30.6% accordingly (P = .046). When patients who were turned down from the emergency surgery were excluded, the 30-day operative mortality was 39.2% and 25.1% during the periods, respectively (P = .051). The 30-day mortality was 16.2% after rEVAR and 40.6% after open surgery (P = .001).

CONCLUSIONS

Simulation training for rEVAR significantly improves the treatment process in real-life patients and may enhance the outcome of rAAA patients.

New Conception of Relining in the Endovascular Aneurysm Sealing Era: A Monocentric Case Series Study

Over 20 years from the first endovascular aortic repair, endoleaks still represent a common problem, even with newer endograft generation. Numerous procedures can be adopted to manage these complications; relining of the endoprosthesis is a rational technique to treat type III and IV endoleaks. The absence of dedicated materials for these procedures forces the vascular surgeon to perform complex hybrid or endovascular interventions. In this case report, we aimed to evaluate our relining experience using the Nellix device in 5 consecutive cases.

[Treatment of an aortic arch aneurysm ruptured into the lung]

Described herein is a clinical case report concerning treatment of a 32-year-old female patient with rupture of an aneurysm of the arch and descending portion of the thoracic aorta, with the bleeding having penetrated the upper lobe of the left lung. The woman was admitted to the Department of Vascular Surgery of Municipal Multimodality Hospital No 2 of Saint Petersburg, presenting with a clinical pattern of aneurysmal rupture previously diagnosed by computed tomography performed at one of the local hospitals. Studying her case history revealed that, when a child, she had endured an operation for a defect of the interventricular septum and aortic coarctation with aortoplasty using a Dacron synthetic patch. On admission, she was treated as an emergency to immediately undergo temporal ascending-descending bypass grafting of the aorta and left common carotid artery without use of a heart-lung machine. After resection of the aneurysm of the arch and descending portion of the thoracic aorta and removal of the upper lobe of the left lung, a decision was made to leave the temporal shunt as permanent. In the early postoperative period the woman developed acute cerebral circulation impairment with minimal neurological deficit which was later on relieved. After 22 days, due to persisting atelectasis of the lower lobe of the left lung, the presence of an incompetent stump of the upper bronchus and air in the left pleural cavity, as well as high risk of infection of the vascular graft, we performed final bilateral pneumonectomy with omentopexy, i. e., suturing of the greater omentum to a portion of the thoracic graft. The woman was discharged on postoperative day 34 in a satisfactory condition. She then successfully gave birth to a child. She is currently presenting neither complaints nor evidence of respiratory insufficiency. The duration of follow up amounted to 8 years.

Potential biomechanical roles of risk factors in the evolution of thrombus-laden abdominal aortic aneurysms

Abdominal aortic aneurysms (AAAs) typically harbour an intraluminal thrombus (ILT), yet most prior computational models neglect biochemomechanical effects of thrombus on lesion evolution. We recently proposed a growth and remodelling model of thrombus-laden AAAs that introduced a number of new constitutive relations and associated model parameters. Because values of several of these parameters have yet to be elucidated by clinical data and could vary significantly from patient to patient, the aim of this study was to investigate the possible extent to which these parameters influence AAA evolution. Given that some of these parameters model potential effects of factors that influence the risk of rupture, this study also provides insight into possible roles of common risk factors on the natural history of AAAs. Despite geometrical limitations of a cylindrical domain, findings support current thought that smoking, hypertension, and female sex likely increase the risk of rupture. Although thrombus thickness is not a reliable risk factor for rupture, the model suggests that the presence of ILT may have a destabilizing effect on AAA evolution, consistent with histological findings from human samples. Finally, simulations support two hypotheses that should be tested on patient-specific geometries in the future. First, ILT is a potential source of the staccato enlargement observed in many AAAs. Second, ILT can influence rupture risk, positively or negatively, via competing biomechanical (eg, stress shielding) and biochemical (ie, proteolytic) effects. Although further computational and experimental studies are needed, the present findings highlight the importance of considering ILT when predicting aneurysmal enlargement and rupture risk.

The Endovascular Management of an Iatrogenic Superior Gluteal Artery Rupture Following Bone Marrow Biopsy

We herein report an uncommon case of a life-threatening retroperitoneal hematoma after a bone marrow biopsy. Two hours after iliac crest bone harvesting, the patient experienced syncope and severe hypotension. Urgent contrast-enhanced computed tomography demonstrated extravasation from the superior gluteal artery. Transcatheter coil embolization was performed successfully, without complications. Life-threatening complications caused by retroperitoneal bleeding after bone marrow biopsy are very rare. There are few reports on the use of endovascular treatment in the management of life-threatening hemorrhagic complications after bone marrow biopsy.

Biomechanical Imaging Markers as Predictors of Abdominal Aortic Aneurysm Growth or Rupture: A Systematic Review

OBJECTIVES

Biomechanical characteristics, such as wall stress, are important in the pathogenesis of abdominal aortic aneurysms (AAA) and can be visualised and quantified using imaging techniques. This systematic review aims to present an overview of all biomechanical imaging markers that have been studied in relation to AAA growth and rupture.

METHODS

This systematic review followed the PRISMA guidelines. A search in Medline, Embase, and the Cochrane Library identified 1503 potentially relevant articles. Studies were included if they assessed biomechanical imaging markers and their potential association with growth or rupture.

RESULTS

Twenty-seven articles comprising 1730 patients met the inclusion criteria. Eighteen studies performed wall stress analysis using finite element analysis (FEA), 13 of which used peak wall stress (PWS) to quantify wall stress. Ten of 13 case control FEA studies reported a significantly higher PWS for symptomatic or ruptured AAAs than for intact AAAs. However, in some studies there was confounding bias because of baseline differences in aneurysm diameter between groups. Clinical heterogeneity in methodology obstructed a meaningful meta-analysis of PWS. Three of five FEA studies reported a significant positive association between several wall stress markers, such as PWS and 99th percentile stress, and growth. One study reported a significant negative association and one other study reported no significant association. Studies assessing wall compliance, the augmentation index and wall stress analysis using Laplace's law, computational fluid dynamics and fluid structure interaction were also included in this systematic review.

CONCLUSIONS

Although PWS is significantly higher in symptomatic or ruptured AAAs in most FEA studies, confounding bias, clinical heterogeneity, and lack of standardisation limit the interpretation and generalisability of the results. Also, there is conflicting evidence on whether increased wall stress is associated with growth.

Rupture of Abdominal Aortic Aneurysm in Patients with and without Antecedent Endovascular Repair

BACKGROUND

Reported results of ruptured abdominal aortic aneurysm (rAAA) in patients with antecedent endovascular aneurysm repair (EVAR) to those presenting with de novo rupture show a similar or slightly improved outcome. The aim of this study was to compare differences in the presentation and outcomes of rAAA with and without prior EVAR.

METHODS

A retrospective review of 121 patients with rAAA, ruptured identified 2 groups. Group A included 17 patients (rAAA n = 17) with antecedent EVAR and group B consisted of 104 patients (rAAA n = 104) with de novo ruptures, from January 2001 to March 2015 in 3 teaching hospitals. Patient characteristics and perioperative variables were compared; Fisher's exact test was used for categorical variables. For continuous variables, Student's t-test and Mann-Whitney U test were used.

RESULTS

Both groups were similar in age, gender, the incidence of hypertension, coronary artery disease, diabetes mellitus, chronic obstructive pulmonary disease, and nicotine abuse. Mean time of presentation from EVAR to rupture in group A was 42 ± 22 months. Mean preoperative transverse or anteroposterior diameter of AAA was 6.6 cm in group A and 7.1 cm in group B. Three patients of 17 (17.6%) in group A were hemodynamically unstable as compared to 47 of 104 patients (45.1%) in group B (P = 0.03). Mean red blood cells, fresh frozen plasma, and platelet transfusion were similar in both groups. Thirty-day mortality was 8 of 17 (44.7%) in group A and 44 of 104 (42.3%) in group B (P = 1.0). Postoperative complications were also similar in both groups except the incidence of postoperative respiratory failure was higher in group B (38%) as compared with 11.1% in group A (P = 0.001).

CONCLUSIONS

Patients presenting with rAAA with antecedent EVAR are hemodynamically more stable as compared with patients with de novo rupture of AAA. Postoperative respiratory failure is more common in patients with de novo rupture. rAAA carry high mortality with and without prior EVAR.

Hypotensive Hemostatis (Permissive Hypotension) for Ruptured Abdominal Aortic Aneurysm: Are We Really in Control?

The purpose of this study was to investigate whether a protocol for permissive hypotension was feasible for patients admitted with a ruptured abdominal aortic aneurysm (RAAA). It was aimed to limit prehospital intravenous fluid administration to 500 mL and to maintain systolic blood pressure at a range of 50 to 100 mm Hg following admission, using nitrates when indicated. The diagnosis of RAAA was confirmed with sonography, and all patients with uncontrolled hypovolemic shock immediately underwent open aneurysm repair (OAR). In all other cases, computed tomographic (CT) angiography was performed to determine the eligibility for endovascular aneurysm repair (EVAR). From January 1, 2004, to December 31, 2006, 95 patients with a suspected RAAA were admitted. In 77 patients, the diagnosis of RAAA was confirmed. Twenty-eight cases (36%) underwent OAR for uncontrolled hemodynamic instability. Following CT-angiographic evaluation, 25 of the remaining 49 cases were considered unsuitable for EVAR and subsequently underwent OAR. In 24 of 77 cases (31%), the RAAA was treated with EVAR. Preoperative systolic blood pressure recordings in EVAR patients showed median values (± SD) of 98 (± 34.7) mm Hg in the emergency department and 114 (± 26.2) mm Hg in the operating theater. The desired systolic blood pressure range of 50 to 100 mm Hg was reached in 11 of 24 cases (46%). In 13 of 24 cases (54%), a systolic blood pressure higher than 100 mm Hg was recorded for a period longer than 60 minutes. The 30-day mortality was 32 of 77 (42%), with 6 of 24 (25%) in the EVAR group and 26 of 53 (49%) in the OAR group. This is the first published series of RAAA in which a protocol of permissive hypotension has been adopted. The concept appeared to be feasible in the majority of cases. Protocol violations were sparse ( n = 5). Uncontrolled hypotension occurred in 36% (28 of 77) of all patients, and the desired systolic blood pressure range was achieved in 46% (11 of 24) of the EVAR patients.

Impact of Delay on Survival in Patients with Ruptured Abdominal Aortic Aneurysm

Rupture of the abdominal aortic aneurysm (RAAA) is a common surgical emergency. Surgical treatment of this condition carries a high morbidity and mortality rate. For successful outcome, an early diagnosis and prompt treatment are essential. However, recently, some centers have reported better results in patients whose surgery had been delayed because of interhospital transfer. Delay in treatment sometimes occurs as patients are transferred from one institution to another where specialized vascular care is available. This retrospective study sought to determine the effect of delay in treatment on the mortality of patients with RAAA repair.

The time from arrival at the emergency room to surgery and operative time were obtained from the case notes of 45 consecutive patients with RAAA. Patients' physiology scores on admission were calculated using V-POSSUM for the RAAA model.

Thirty-five patients were diagnosed with RAAA in the emergency room and were transferred to surgery. These patients were divided into two groups: patients who had surgery within 1 hour ( n = 23) and those in whom surgery was delayed for up to 4 hours ( n = 12).

There was no significant difference in physiology score between the two groups ( p = .12). The time to surgery and operative time with death as the outcome were plotted on a logistic regression model that showed that the delay in surgical treatment increases the mortality rate following RAAA repair ( p = .041). Furthermore, a long operative time was associated with a higher surgical mortality rate ( p = .029).

Delay to surgery and a long operation increase the mortality rate following RAAA repair. However, delay to surgery alone did not influence the mortality rate.

[Endovascular and surgical treatment of a patient with traumatic rupture of the aorta and hepatic artery]

Traumatic rupture of the aorta is the second most common cause of death in closed chest injury. The latest findings of autopsy showed that 80% of lethal outcomes in aortic injury occur in the prehospital period. Taking into consideration the incidence and high rate of death prior to the diagnosis stage, aortic rupture in closed thoracic injury is an important problem. Due to the characteristic mechanism of the development (during sharp deceleration of the body) this type of traumatic lesion of the aorta became known as "deceleration syndrome". The most vulnerable to tension aortic portion is its neck where the mobile part of the thoracic aorta is connected to the fixed arch in the place of the arterial ligament attachment. Open surgical intervention in patients with severe closed chest injury (often concomitant injury) is associated with high mortality and complications. Currently endovascular prosthetic repair of the aorta is a method of choice at the primary stage of treatment of patients with aortic injury. In this article we present a rare case report of concomitant lesion of large vessels (the descending aortic portion and proper hepatic artery) in a patient with severe concomitant injury, as well as peculiarities of diagnosis and combined treatment (endovascular prosthetic repair of the aorta and hepatic artery with an aotovein).

Role of mechanotransduction in vascular biology: focus on thoracic aortic aneurysms and dissections

Thoracic aortic diseases that involve progressive enlargement, acute dissection, or rupture are influenced by the hemodynamic loads and mechanical properties of the wall. We have only limited understanding, however, of the mechanobiological processes that lead to these potentially lethal conditions. Homeostasis requires that intramural cells sense their local chemomechanical environment and establish, maintain, remodel, or repair the extracellular matrix to provide suitable compliance and yet sufficient strength. Proper sensing, in turn, necessitates both receptors that connect the extracellular matrix to intracellular actomyosin filaments and signaling molecules that transmit the related information to the nucleus. Thoracic aortic aneurysms and dissections are associated with poorly controlled hypertension and mutations in genes for extracellular matrix constituents, membrane receptors, contractile proteins, and associated signaling molecules. This grouping of factors suggests that these thoracic diseases result, in part, from dysfunctional mechanosensing and mechanoregulation of the extracellular matrix by the intramural cells, which leads to a compromised structural integrity of the wall. Thus, improved understanding of the mechanobiology of aortic cells could lead to new therapeutic strategies for thoracic aortic aneurysms and dissections.

[Endovascular treatment of spontaneous rupture of the thoracic aorta]

Spontaneous rupture of the aorta is an uncommonly encountered acute surgical aortic pathology characterised by an utterly unfavourable prognosis. The article deals with a case report concerning successful endovascular treatment of spontaneous rupture of the thoracic portion of the aorta, followed by discussion of problems regarding aetiology, diagnosis, and therapeutic policy for such pathology.

Patient-specific finite element analysis of ascending thoracic aortic aneurysm

BACKGROUND AND AIM OF THE STUDY

Rupture/dissection of ascending thoracic aortic aneurysm (aTAA) is a cardiovascular emergency. Elective surgical repair is primarily based on maximum diameter, but complications have occurred under the size limits for surgical intervention. aTAA wall stress may be a better predictor of patient-specific rupture risk, but cannot be directly measured in vivo. The study aim was to develop an aTAA computational model associated with tricuspid aortic valve (TAV) to determine patient-specific wall stresses.

METHODS

A TAV-associated aTAA was excised intact during surgery. Zero-pressure geometry was generated from microcomputed tomography, and an opening angle was used to calculate residual stress. Material properties determined from stress-strain data were incorporated into an Ogden hyperelastic model. Wall stress distribution and magnitudes at systemic pressure were determined using finite element analyses (FEA) in LS-DYNA.

RESULTS

Regional material property differences were noted: the left aTAA region had a higher stiffness compared to the right, and anterior/posterior walls. During systole, the mean principal wall stresses were 172.0 kPa (circumferential) and 71.9 kPa (longitudinal), while peak wall stresses were 545.1 kPa (circumferential) and 430.1 kPa (longitudinal). Elevated wall stress pockets were seen in anatomic left and right aTAA regions.

CONCLUSION

A validated computational approach was demonstrated to determine aTAA wall stresses in a patient-specific fashion, taking into account the required zero-stress geometry, wall thickness, material properties and residual stress. Regions of maximal wall stress may indicate the sites most prone to rupture. The creation of a patient-specific aTAA model based on a surgical specimen is necessary to serve as the 'gold standard' for comparing models based on in-vivo data alone. Validated data using the surgical specimen are essential for establishing wall stress and rupture-risk relationships.

[Valve-sparing technique for type a aortic dissection with insufficiency of aortic valve]

This article describes clinical experience of surgical treatment of aortic insufficiency in type A aortic dissection using valve-sparing technique. Results of treatment are presented.

Antegrade versus retrograde cerebral perfusion for hemiarch replacement with deep hypothermic circulatory arrest: does it matter? A propensity-matched analysis

OBJECTIVE

The choice of cerebral perfusion strategy for aortic arch surgery has been debated, and the superiority of antegrade (ACP) or retrograde (RCP) cerebral perfusion has not been shown. We examined the early and late outcomes for ACP versus RCP in proximal (hemi-) arch replacement using deep hypothermic circulatory arrest (DHCA).

METHODS

A retrospective analysis of a prospectively maintained database was performed for all patients undergoing elective and nonelective hemiarch replacement at a single referral institution from June 2005 to February 2013. Total arch cases were excluded to limit the analysis to shorter DHCA times and a more uniform patient population for whom clinical equipoise regarding ACP versus RCP exists. A total of 440 procedures were identified, with 360 (82%) using ACP and 80 (18%) using RCP. The endpoints included 30-day/in-hospital and late outcomes. A propensity score with 1:1 matching of 40 pre- and intraoperative variables was used to adjust for differences between the 2 groups.

RESULTS

All 80 RCP patients were propensity matched to a cohort of 80 similar ACP patients. The pre- and intraoperative characteristics were not significantly different between the 2 groups after matching. No differences were found in 30-day/in-hospital mortality or morbidity outcomes. The only significant difference between the 2 groups was a shorter mean operative time in the RCP cohort (P = .01). No significant differences were noted in late survival (P = .90).

CONCLUSIONS

In proximal arch operations using DHCA, equivalent early and late outcomes can be achieved with RCP and ACP, although the mean operative time is significantly less with RCP, likely owing to avoidance of axillary cannulation. Questions remain regarding comparative outcomes with straight DHCA and lesser degrees of hypothermia.

The role of permissive hypotension in the management of ruptured abdominal aortic aneurysms

The aim of this review was to explore current literature pertaining to the use of permissive hypotension in the treatment of abdominal aortic aneurysms. A literature search using Metalib, a database search engine, provided at the Royal Free and University College of London (UCL) yielded articles using the keywords "permissive hypotension" and "hypotensive resuscitation" when linked to "abdominal aortic aneurysm" and "rupture". The articles studying permissive hypotension in animals and humans in trauma, and in patients with abdominal aortic aneurysm were reviewed. The result of this search was a large volume of experimental studies of trauma in animals giving satisfactory evidence of the physiological benefit of this concept of resuscitation in trauma. There were some randomized trials in humans in trauma suggesting benefit. The safety of permissive hypotension in patients with ruptured aortic aneurysms was documented and found to be widespread, but there were no randomized trials directly comparing this practice. Evidence from a prospective randomized study on the modality of treatment of ruptured aortic aneurysms suggest that the level of blood pressure is associated with the mortality and a prospective cohort study suggests that, using the complementary concept of "delayed volume resuscitation", the total volume of preoperative fluid resuscitation independent of the blood pressure is predictive of the risk of perioperative death in ruptured aortic aneurysms. To this end, recent clinical publications are now supportive of control of both the volume of preoperative fluid given and blood pressure in this group of patients but clinical studies are few.

Molecular mechanisms of thoracic aortic dissection

Thoracic aortic dissection (TAD) is a highly lethal vascular disease. In many patients with TAD, the aorta progressively dilates and ultimately ruptures. Dissection formation, progression, and rupture cannot be reliably prevented pharmacologically because the molecular mechanisms of aortic wall degeneration are poorly understood. The key histopathologic feature of TAD is medial degeneration, a process characterized by smooth muscle cell depletion and extracellular matrix degradation. These structural changes have a profound impact on the functional properties of the aortic wall and can result from excessive protease-mediated destruction of the extracellular matrix, altered signaling pathways, and altered gene expression. Review of the literature reveals differences in the processes that lead to ascending versus descending and sporadic versus hereditary TAD. These differences add to the complexity of this disease. Although tremendous progress has been made in diagnosing and treating TAD, a better understanding of the molecular, cellular, and genetic mechanisms that cause this disease is necessary to developing more effective preventative and therapeutic treatment strategies.

Extensive endovascular repair of thoracic aorta: observational analysis of the results and effects on spinal cord perfusion

AIM

The study aims to analyze retrospective results of extensive endovascular repair of the descending thoracic aorta with special attention to spinal cord malperfusion.

METHODS

From April 2002 through November 2011, 21 patients underwent stent-graft coverage of the thoracic aorta from the aortic arch at the origin of the left subclavian artery to the celiac trunk, 6 (mean age =72.3±8.1) for aneurysm disease, 13 (mean age =74.3±8.4) for type B aortic dissection and 2 (mean age =52.1±6.5) for aortic rupture. The mean of aortic diameter in cases with aneurysm disease was 7.1±1.6 cm and the causes of aortic rupture were post-traumatic and aneurysm pathology respectively. In all cases needing coverage of the left subclavian artery duplex ultrasonography and flowmetry were performed to evaluate patency and flow of both the vertebral arteries.

RESULTS

Technical success was 100% with 0% in-hospital mortality. The left subclavian artery was crossed with the uncovered portion of the stent-graft in 11 cases (52.4%) and the covered segment in the other 10 patients (47.6%) without subclavian revascularization because no pre-operative hemodynamic alterations of vertebral arteries were revealed by duplex ultrasonography. The incidence of paraplegia was 9.5% in 2 patients who had prior abdominal aortic aneurysm repair: the first case with preoperative type B aortic dissection presented significant lower extremity paresis within 24 hours after the procedure and in the second patient with a large thoracic aneurysm the signs of paraplegia were evident 3 weeks after discharge from Hospital probably due to delayed occlusion of a major medullary artery. The cumulative survival rate after 1, 3 and 9 years was 91%, 81%, and 71%.

CONCLUSIONS

The coverage of the entire thoracic aorta is an effective procedure with high probability of success. Spinal cord malperfusion remains a serious complication especially in patients with prior aortic surgery but if collateral blood supply is maintained the occlusion of intercostal arteries do not determine paraplegia or paraparesis. In order to consider acute or chronic occlusion of subclavian, lumbar or hypogastric arteries so preventing spinal cord ischemia, strong preoperative evaluation including analysis of previous surgery for abdominal aortic aneurysm repair and avoidance of T12 aortic segment coverage if feasible is mandatory.

Haemodynamic predictors of a penetrating atherosclerotic ulcer rupture using fluid-structure interaction analysis

We present preliminary data on the flow-induced haemodynamic and structural loads exerted on a penetrating atherosclerotic aortic ulcer (PAU). Specifically, one-way fluid-structure interaction analysis was performed on the aortic model reconstructed from a 66-year-old male patient with a PAU that evolved into an intramural haematoma and rupture of the thoracic aorta. The results show that elevated blood pressure (117 mmHg) and low flow velocity at the aortic wall (0.15 m/s(2)) occurred in the region of the PAU. We also found a low value of time-averaged wall shear stress (1.24 N/m(2)) and a high value of the temporal oscillation in the wall shear stress (oscillatory shear index = 0.13) in the region of the PAU. After endovascular treatment, these haemodynamic parameters were distributed uniformly on the luminal surface of the stent graft. These findings suggest that wall shear stress could be considered one of the major haemodynamic factors indicating the structural fragility of the PAU wall, which ultimately lead to PAU growth and rupture.

Biomechanical roles of medial pooling of glycosaminoglycans in thoracic aortic dissection

Spontaneous dissection of the human thoracic aorta is responsible for significant morbidity and mortality, yet this devastating biomechanical failure process remains poorly understood. In this paper, we present finite element simulations that support a new hypothesis for the initiation of aortic dissections that is motivated by extensive histopathological observations. Specifically, our parametric simulations show that the pooling of glycosaminoglycans/proteoglycans that is singularly characteristic of the compromised thoracic aorta in aneurysms and dissections can lead to significant stress concentrations and intra-lamellar Donnan swelling pressures. We submit that these localized increases in intramural stress may be sufficient both to disrupt the normal cell-matrix interactions that are fundamental to aortic homeostasis and to delaminate the layered microstructure of the aortic wall and thereby initiate dissection. Hence, pathologic pooling of glycosaminoglycans/proteoglycans within the medial layer of the thoracic aortic should be considered as a possible target for clinical intervention.

[The results of treatment of the patients with the rupture of abdominal aortic aneurysms in multifield hospital]

The rupture of infrarenal segment of aorta is the severe pathology in spite of modem diagnostics and the operation. This case is accompanied by negative results of treatment (lethality consists of 56,3%). The article presents the experience of treatment of 157 patients with the rupture of infrarenal segment of aorta in conditions of multifield hospital (Municipal hospital No 26). The authors highlighted the postoperative complications, their influence on negative outcome. It was shown, that the main reasons of negative outcome of such patients with abdominal aortic aneurism, complicated by the rupture, were an advanced age of patients, who had the complex of concomitant diseases and postoperative complications such as nosocomial pneumonia, cardiac problems and multiple organ failure due to massive acute hemorrhage.

Aortic valve regurgitation that resolved after a ruptured coronary sinus aneurysm was patched

Sinus of Valsalva aneurysms appear to be rare. They occur most frequently in the right sinus of Valsalva (52%) and the noncoronary sinus (33%). More of these aneurysms originate from the right coronary cusp than from the noncoronary cusp. Surgical intervention is usually recommended when symptoms become evident. We report the case of a 34-year-old woman who presented with a congenital, ruptured sinus of Valsalva aneurysm that originated from the noncoronary cusp. Moderate aortic regurgitation was associated with this lesion. Simple, direct patch closure of the ruptured aneurysm resolved the patient's left-to-right shunt and was associated with decreased aortic regurgitation to a degree that valve replacement was not necessary. Only trace residual aortic regurgitation was evident after 3 months, and the patient remained free of symptoms after 6 months. Our observations support the idea that substantial runoff blood flow in the immediate supra-annular region can be responsible for aortic regurgitation in the absence of a notable structural defect in the aortic valve, and that restoring physiologic flow in this region and equalizing aortic-cusp closure pressure can largely or completely resolve aortic insufficiency. Accordingly, valve replacement may not be necessary in all cases of ruptured sinus of Valsalva aneurysms with associated aortic valve regurgitation.

Surgical treatment of symptomatic and ruptured abdominal aortic aneurysms

Despite the increased volume of patients undergoing selective reconstruction on the occasion of abdominal aortic aneurysms (AAA) in the last decades, the number of patients with rupture of abdominal aortic aneurysms (RAAA) is not significantly decreased. RAAA is catastrophic and life-threatening condition. It remains a challenge to every practitioner. To optimize the surgical practice we studied the literature for the treatment of symptomatic and rupture aneurysm of the abdominal aorta.

A single-centre experience of the treatment of ruptured abdominal aortic aneurysms: clinical and anatomic characteristics of open versus endovascular repair

AIM

The treatment of ruptured abdominal aortic aneurysms is a constant challenge for vascular surgeons and can be achieved either by endovascular repair or by an open surgical technique. Endovascular repair presents a higher 30-day survival rate. The aim of this study was to compare the clinical and anatomical characteristics and the outcomes of these two treatment techniques.

METHODS

Our study sample comprised patients who presented at the emergency department of a General Regional Hospital with rupture of an abdominal aortic aneurysm between January 2003 and December 2008. Of the 43 patients who were treated, 23 underwent open surgical repair and 20 underwent endovascular repair.

RESULTS

Comorbidities, age, clinical presentation and anatomical characteristics didn't present statistically significant differences in the two groups. Patients in the endovascular repair group were transfused with less units of blood and fresh frozen plasma (P=0.001) and had shorter stay in the intensive care unit (P=0.042). The 30-day mortality rate was 43% for open surgical repair and 35% for endovascular treatment (P=0.627), while the overall in-hospital mortality rate was 61% and 50% (P=0.474), respectively.

CONCLUSION

When certain anatomical characteristics are present and the hemodynamic condition of the patient allows it, endovascular treatment appears to be associated with better survival rates, both 30-day and overall.

Emergent repair of a complex dissecting aneurysm in the thoracic aorta

Endovascular treatment of complex thoracic pathologic conditions involving the aortic arch can often be appropriate and safe; however, minimally invasive procedures are not always feasible, especially in emergent cases. We report the case of a 78-year-old woman who emergently presented in hemorrhagic shock with a ruptured chronic dissecting aneurysm that involved the aortic arch. Eight years earlier, she had undergone aortic valve replacement and plication of the ascending aorta, which was complicated a day later by Stanford type B dissection, malperfusion, and ischemia that required an axillobifemoral bypass. At the current admission, we successfully treated her surgically through a left thoracotomy, using moderate hypothermic extracorporeal circulation and advanced organ-protection methods. We discuss the surgical indications and our operative strategy in relation to open surgical repair versus endovascular treatment in patients with complex conditions.

[The changes of intraabdominal pressure in patients with retroperitoneal bleeding]

The linear dependence of the intraabdominal pressure and the volume of retroperitoneal bleeding was revealed in 34 patients with the aortic aneurism rupture. In patients with the blunt abdominal trauma, treated conservatively and laparotomized (each group consisted of 26 patients), the intraabdominal pressure is higher in the operated group during the first day after the operation. The main factors of the intraabdominal hypertension seem to be shock and massive infusion and transfusion therapy.

[Treatment of a patient with a ruptured infectious aneurysm of the aortic arch]

Described in the article is a clinical case report concerning surgical treatment of a 65-year-old male patient presenting with a ruptured infectious aortic arch aneurysm. He was subjected to an operation consisting in prosthetic repair of the ascending portion of the aorta and aortic arch with a homograft under conditions of artificial circulation, deep hypothermia, and antegrade cerebral perfusion.

[Remote results of open interventions in treatment of abdominal aortic aneurysms]

Analysed herein are the results of treating a total of 471 patients operated on at the Department of Surgical Treatment for Arterial Pathology of the Research Centre of Cardiovascular Surgery named after A. N. Bakulev under the Russian Academy of Medical Sciences for an aneurysm of the infrarenal portion of the abdominal aorta. Complicated forms of AAA were observed in 71 (15.1%) patients. Of these, 13 patients were admitted presenting with a clinical picture of aortic rupture, 56 patients with aortic wall tear (according to ultrasound and/or MSCH findings), and two patients had break of the inferior vena cava. The most frequently encountered accompanying diseases were as follows: CAD noted in 367 (78.2%) patients. Valvular heart defects were revealed in 68 (14.4%) patients. Atherosclerotic alterations of the ascending aorta were diagnosed in 97 (20.6%) patients, and an ascending aortic aneurysm in 14 (2.8%) patients. Operations on the heart were performed in 45 (19.1%) patients. Mitral valve plasty was carried out in 7 patients, and 11 patients had a history of prior interventions on the aortic root and ascending aorta (Bentall-De Bono operation in 3 patients, Carbol operation in 3 patients). 32 patients underwent reconstructive operations on coronary arteries. Transmyocardial laser revascularization of the myocardium was carried out in 4 patients. Endovascular interventions were performed in 32 (6.8%) patients (stenting or transluminal balloon angioplasty of coronary arteries). All patients underwent AAA resection with prosthetic repair. The mentioned operations were combined with the following simultaneous interventions: aortocoronary bypass grafting performed in 31 cases, carotid endarterectomy in 27 cases, and plasty of renal arteries was carried out in 48 patients. Complications in the immediate postoperative period were observed in 79 (16.8%) patients. Hospital mortality amounted to 11 (2.3%) patients. The cumulative survival rate after 1, 5 and 10 years after surgery amounted to 93%, 81% and 44%, respectively, in a complicated course amounting to 91%, 79% and 16%, respectively. The obtained findings of the study demonstrated that the results of the AAA resection should be regarded as fairly good. The main factors influencing the quality of life and surgical outcomes in abdominal aortic aneurysms are as follows: CAD, arterial hypertension, and chronic cerebrovascular diseases. In patients without accompanying diseases, the criteria of quality of life after surgery approximate to those in a healthy population.

[Penetrating atherosclerotic ulcers of the aorta]

Widespread use of various present-day visual methods of study has made it possible to increase the frequency of revealing penetrating atherosclerotic ulcers, known to be ulcerations of an atherosclerotic plaque thorough the intimal elastic lamina into the medial layer of the aortic wall. The review deals with the literature data regarding the clinical picture, pathogenesis, diagnosis, policy of management and treatment of complications of penetrating atherosclerotic ulcers. The problem concerning the choice between surgical and endovascular treatment of penetrating atherosclerotic ulcers has been elucidated insufficiently in the present-day literature.

Retrograde coronary sinus cardioplegia cannula placement under short-time circulatory arrest in surgery for a ruptured type A dissection with a previous coronary artery bypass

A 79-year-old woman was referred to undergo surgery for a type A dissection. The patient had a history of previous coronary artery bypass. She was in shock and had a hematoma surrounding the ascending aorta and the heart. In this case, a coronary sinus cardioplegia cannula was placed under a short period of circulatory arrest via a small atriotomy, and the atriotomy was closed immediately to establish selective cerebral perfusion.

Analysis of aortic wall stress and rupture risk in patients with abdominal aortic aneurysm with a gender perspective

OBJECTIVE

The most commonly used predictor of rupture of an abdominal aortic aneurysm (AAA) is the diameter; however, this does not estimate the true risk for each patient. Why women with AAAs have an increased growth rate, weaker aortic wall, and increased risk for rupture is yet unclear. It is likely that geometrical and biomechanical properties contribute to found gender differences. Several studies have shown that peak wall stress (PWS) and peak wall rupture risk (PWRR), predicted by a finite element (FE) analysis of AAAs derived from computed tomography (CT), is a better predictor of rupture than maximum diameter. The purpose of this study was to investigate if women with AAAs have an increased PWS and PWRR using an FE model compared to men.

METHOD

Fifteen men and 15 women (AAAs 4-6 cm) were included. AAA geometry was derived from CT scans, and PWS and PWRR were estimated using the FE method. Comparisons were made by t test and Mann-Whitney test.

RESULTS

Mean age (women 73 years old vs men 71 years old) and mean AAA diameter was similar (49.7 mm vs 50.1 mm) for women and men. PWS did not differ for women 184 and men 198 kPa. PWRR was 0.54 (0.28-0.85) for women and 0.43 (0.24-0.66) for men, P = .06.

CONCLUSION

This is the first analysis of stress and strength of the aneurysm wall with a gender perspective. The reported higher rupture risk for women has previously not been tested with geometrical and biomechanical properties. PWS did not differ, but the PWRR was slightly higher in women. However, the difference did not reach statistical significance, probably due to the small sample size. In summary, the results in the present study suggest that differences in biomechanical properties could be a contributing explanation for the higher rupture risk reported for female patients with AAAs.

[Diagnosis and options for reconstructive heart valve surgery in the Marfan syndrome]

Marfan syndrome is a disorder of the connective tissue that is inherited in an autosomal-dominant fashion and that is caused by mutations in the gene coding for fibrillin-1, FBN1. Although complications of the syndrome may involve the eye, the lung and the skeleton, the high mortality of untreated cases results almost exclusively from cardiovascular complications, including aortic dissection, rupture and mitral valve regurgitation. The multiorgan involvement of many of these syndromes requires multidisciplinary expert centers that can increase the average life expectancy of affected patients from only 32 years to over 60 years. The present article both reviews classical standards of managing cardiovascular manifestations and highlights the surgical approach for aortic and mitral valve surgery in Marfan patients.

Patient based abdominal aortic aneurysm rupture risk prediction combining clinical visualizing modalities with fluid structure interaction numerical simulations

Fluid structure interaction (FSI) simulations of patient-specific fusiform non-ruptured and contained ruptured Abdominal Aortic Aneurysm (AAA) geometries were conducted. The goals were: (1) to test the ability of our FSI methodology to predict the location of rupture, by correlating the high wall stress regions with the rupture location, (2) estimate the state of the pathological condition by calculating the ruptured potential index (RPI) of the AAA and (3) predict the disease progression by comparing healthy and pathological aortas.

Choice of treatment for the patient with urgent AAA: practical tips

Since the first successful attempts of emergency endovascular aneurysm repair (eEVAR) for patients with ruptured AAAs in the mid 1990s, surgeons have had to decide whether to treat patients by conventional open surgery or by minimally invasive but technically more demanding eEVAR. To date, selection of patients for eEVAR is still heavily debated and factors like hemodynamic instability, fear of treatment delay for patient transfer or imaging procedures and logistic issues often lead to the exclusion of anatomically suitable patients from eEVAR. However, these adverse factors may be overcome by adherence to an appropriate (intention-to-treat) protocol employing the use of a hypotensive hemostatic approach, transfemoral aortic balloon occlusion technique (when needed), different types of devices and an appropriate plan to resolve logistic issues, leaving anatomic suitability as the single most important determinant of suitability for EVAR.

Mortality of ruptured abdominal aortic aneurysm with selective use of endovascular repair

The aim of this review was to examine the results over a seven-year period of treatment for ruptured abdominal aortic aneurysm (RAAA). From 2002 on, our tertiary referral centre offered both open and endovascular (EVAR) treatment modalities for RAAA. All patients with a proven RAAA who were admitted into our hospital were included. Primary outcome measure was surgical mortality. In total 261 patients were admitted with suspicion of acute AAA. Of these, 175 (67%) had a RAAA, confirmed by computed tomography-scanning or at laparotomy. One hundred and fifty-nine patients (90.9%) were treated, 114 by open repair and 45 by EVAR. Overall mortality of patients treated was 25.2%, with an open repair mortality of 27.2%, and EVAR mortality of 20%. EVAR was used more often in patients who were hemodynamically more stable. Evaluation for EVAR and treatment by EVAR increased during the study period. Overall mortality rate for treatment of RAAA in our centre was 25% over the seven-year study period.