Are aortic aneurysms caused by atherosclerosis?

Friesian horses as a possible model for human acquired aortopulmonary fistulation

Background

Acquired aortopulmonary fistulation is a rare condition in humans. It usually results as a late complication of a true or pseudoaneurysm of the thoracic aorta. It is most commonly associated with trauma or surgery, less commonly with atherosclerosis, inflammation, hypertension or Marfan’s syndrome. Aortopulmonary fistulation is also seen as a rare complication of acute aortic dissection. On rare occasions, acquired aortopulmonary fistulation is reported in aged patients without any of the above mentioned triggering factors. Thus, these cases should be considered as idiopathic aortopulmonary fistulation. Clearly, the pathogenesis of this condition is not yet completely understood. Friesian horses are highly inbred and are affected by several genetic conditions. Rupture of the thoracic aorta has a relatively high prevalence in Friesian horses and is often characterized by the formation of a pseudoaneurysm with subsequent fistulation into the pulmonary artery. Affected animals may survive for several weeks to months.

Findings

Here we performed vascular casting in three affected Friesian horses. In all three cases, an aortic rupture at the caudoventral side of the aorta was connected with a rupture of the main pulmonary artery just proximal to its bifurcation.

Conclusions

Affected Friesians show a consistent location and configuration of the aortic rupture site, very similar to the human condition and therefore could act as a spontaneous model to study this disease.

Electronic supplementary material

The online version of this article (doi:10.1186/s13104-016-2201-5) contains supplementary material, which is available to authorized users.

Biology of Saccular Cerebral Aneurysms: A Review of Current Understanding and Future Directions

Understanding the biology of intracranial aneurysms is a clinical quandary. How these aneurysms form, progress, and rupture is poorly understood. Evidence indicates that well-established risk factors play a critical role, along with immunologic factors, in their development and clinical outcomes. Much of the expanding knowledge of the inception, progression, and rupture of intracranial aneurysms implicates inflammation as a critical mediator of aneurysm pathogenesis. Thus, therapeutic targets exploiting this arm of aneurysm pathogenesis have been implemented, often with promising outcomes.

Aortic Dissection: A Dreaded Disease with Many Faces

Aortic dissection is a relatively uncommon but catastrophic illness classically thought to present with acute, sharp, chest pain with radiation to the back. However, aortic dissection can manifest in a number of different ways that include congestive heart failure, inferior myocardial infarction, stroke, focal pulse and neurologic deficits, abdominal pain, or acute renal failure. According to some studies, only about 80% of patients with type A dissection present with severe anterior chest pain, and only about 60% describe their pain as being sharp. Another series reports that treating clinicians fail to initially entertain the diagnosis of aortic dissection in up to 35% of cases. Many patients later found to have aortic dissection are initially suspected to have other conditions such as acute coronary syndrome, pericarditis, pulmonary embolism, or even cholecystitis. In this article we present a case of an unusual presentation of aortic dissection and a review of this condition.

Statin Use Is Associated with Reduced All-Cause Mortality after Endovascular Abdominal Aortic Aneurysm Repair

It has been shown that preoperative statin therapy reduces all-cause and cardiovascular mortality in patients undergoing major noncardiac vascular surgery. In this report, we investigated the influence of statin use on early and late outcome following endovascular abdominal aortic aneurysm repair (EVAR).

The study population, consisting of patients collated in the EUROSTAR registry, was stratified in two groups according to statin use. Baseline characteristics between the two groups were compared by chi-square and Wilcoxon rank sum tests for discrete and continuous variables. The effects of statin use on outcomes after EVAR were analyzed by multivariate regression models.

Of the 5,892 patients enrolled in the EUROSTAR registry, 731 (12.4%) patients used statins for hyperlipidemia. Statin users were younger, were more obese, and had a higher prevalence of diabetes, cardiovascular disease, and hypertension. After 5 years of follow-up, the cumulative survival rate was 77% for nonusers of statin versus 81% for statin users ( p = .005). After adjustment for age and other risk factors, statin use was still an independent predictor of improved survival ( p = .03).

Our results revealed that statin prescription was more frequent in younger patients. However, when adjusted for age and medical risk factors, the use of statin in patients who underwent EVAR was still independently associated with reduced overall mortality.

Medical Therapy Approach for Treating Abdominal Aortic Aneurysm

Abdominal aortic aneurysm (AAA) is a common and deadly problem. The aortic diameter increases in association with a complex remodeling process that includes changes in the structure and content of key proteins, elastin and collagen. As these changes occur, the tissue mechanical properties also change. The natural history of AAA is progressive enlargement to a point of mechanical tissue failure, typically followed by death. Currently, the marker used to predict the risk of impending rupture is the largest transverse diameter. After reaching a diameter threshold of 5.5 cm, the aneurysm is surgically repaired. This criterion does not consider any patient-specific information or the known heterogeneity of the aneurysm that may, in some cases, lead to rupture before the aneurysm reaches the standard intervention threshold. Conversely, in many patients, continued observation beyond this threshold is safe. Although no medical treatment is yet approved, doxycycline has been shown to greatly reduce aortic aneurysm growth in animal models and has been shown to slow growth in several small clinical trials. Although larger prospective randomized trials are needed, one unknown is what effect doxycycline has on the structural integrity of the aortic wall. That is, does slowed aneurysm growth by doxycycline treatments, in fact, prevent rupture, or does the wall continue to weaken and the aneurysm instead ruptures at a smaller diameter? Research has begun to answer these questions before a large clinical trial begins.

Screening for Peripheral Arterial Disease and Carotid Artery Disease in Patients With Abdominal Aortic Aneurysm

Screening for concomitant atherosclerotic disease is important in cardiovascular risk reduction. This study assessed the prevalence of carotid artery disease (CAD) and peripheral arterial disease (PAD) in patients with known abdominal aortic aneurysms (AAAs). All patients with AAA attending the vascular laboratory between the January 1, 2007, and December 31, 2009, were eligible for a carotid ultrasound and measurement of ankle brachial indices. A total of 389 (305 males) patients were identified on the AAA surveillance program with a mean (±standard deviation) age of 76 (±8) years. The mean age of the males was 75.4 (±7.8) years, and the mean age of the females was 77 (±11) years. A total of 332 patients were assessed for CAD, and 101 (30.4%) of those were found to have significant disease. A total of 289 patients were assessed for PAD of which 131 (45.3%) were found to have PAD at rest, and 289 patients were assessed for both and 59 (20.4%) patients had significant CAD + PAD. Patients with AAAs are at high risk of other atherosclerotic disorders, and, therefore, they should receive intensive medical optimization.

Computational hemodynamics of abdominal aortic aneurysms: Three-dimensional ultrasound versus computed tomography

The current criterion for surgical intervention in abdominal aortic aneurysms, based upon a maximal aortic diameter, is considered conservative due to the high mortality rate in case of rupture. The research community is actively investigating the use of computational mechanics tools combined with patient-specific imaging to help identify more accurate criteria. Widespread uptake of a successful metric will however be limited by the need for computed tomography, which is at present the primary image extraction method on account of the location and complex shape of the aneurysms. The use of three-dimensional ultrasound as the scanning method is more attractive on account of increased availability, reduced cost and reduced risk to patients. The suitability of three-dimensional ultrasound is assessed for this purpose in the present work; computational fluid dynamics simulations were performed on geometries obtained from the same patient using both ultrasound and computed tomography. The influence of different smoothing algorithms is investigated in the geometry preparation stage and Taubin’s low-pass filter was found to best preserve geometry features. Laminar, Newtonian, steady-state simulation analysis identified haemodynamic characteristics to be qualitatively similar in terms of wall shear stress, velocity and vorticity. The study demonstrates the potential for three-dimensional ultrasound to be integrated into a more accessible patient-specific modelling tool able to identify the need for surgical intervention of abdominal aortic aneurysms.

Malperfusion syndromes in aortic dissections

Aortic dissection remains a challenging clinical scenario, especially when complicated by peripheral malperfusion. Improvements in medical imaging have furthered understanding of the pathophysiology of malperfusion events in association with aortic dissection, including the elucidation of different mechanisms of branch vessel obstruction. Despite these advances, malperfusion syndrome remains a deadly entity with significant mortality. This review presents the latest knowledge regarding the pathogenesis of aortic dissection complicated by malperfusion syndrome, and discusses the diagnostic and therapeutic guidelines for management of this vicious entity.

B lymphocytes in abdominal aortic aneurysms

Abdominal aortic aneurysm (AAA) is a progressive inflammatory disease of the artery walls. Immune cells, including B lymphocytes, are implicated in the pathogenesis of AAA through interconnected mechanisms. Many studies have shown that compared with normal abdominal aortic tissue, the amount of B lymphocytes that infiltrate the adventitia of AAAs was significantly higher. Activated B lymphocytes promote AAA by producing immunoglobulins, cytokines, and matrix metalloproteinases (MMPs), resulting in the activation of macrophages, mast cells (MCs) and complement pathways. Finally, all of these factors lead to the degradation of collagen and matrix proteins and to aortic wall remodeling, which are hallmarks of AAA. However, few studies focus on the relative function of B cells, and their precise mechanisms in AAA remain unclear. Thus, we summarize the current knowledge on the role of B cells in AAA and offer recommendations for further investigation of preventing the progression of AAA.

The impact of obstructive sleep apnoea on the aorta

Obstructive sleep apnoea (OSA) has been shown to be a causal factor in the pathogenesis of vascular dysfunction and hypertension, conditions which can promote dilation and subsequent aortic dissection and rupture. The objective of this review is to summarise the current literature on the possible association between OSA and aortic disease and delineate the underlying mechanisms.

Relevant studies were found by searching for terms including “obstructive sleep apnoea” in combination with “aortic aneurysm, dissection, and dilation” in the MEDLINE and EMBASE databases.

Observational studies consistently reported that OSA is highly prevalent among patients with aortic aneurysms and aortic dissections. Patients with co-occurring OSA and Marfan's syndrome as well as patients at the more severe end of the spectrum of OSA seem to be especially vulnerable to aortic disease.

Several mechanisms are discussed concerning the link between OSA and aortic disease: nocturnal negative intrathoracic pressure surges leading to mechanical stretching of the aorta and ultimately aortic distension; arousal-induced reflex sympathetic activation with subsequent hypertension; and intermittent hypoxia associated with autonomic nervous system activation and consequently increased oxidative stress. Further well controlled studies are needed in order to define the exact role of OSA as a risk factor for aortic disease.

Ortner's syndrome presenting as thoracic aortic aneurysm mimicking thoracic malignancy: a case report

Introduction

Ortner’s syndrome is defined as left recurrent laryngeal nerve palsy caused by a cardiovascular pathology. Here we report the case of a 68-year-old man who presented to our hospital with hoarseness, whose initial chest imaging mimicked a thoracic neoplastic process with left pleural effusion. The final diagnosis was Ortner’s syndrome due to the silent rupture of a thoracoabdominal aortic aneurysm. Diagnostic thoracentesis, before computed tomography, in resource-poor settings, may have resulted in an adverse outcome in our case.

Case presentation

A 68-year-old Sri Lankan man was referred to us by an otolaryngologist for further evaluation of a suspected thoracic malignancy. His presenting symptom was hoarseness of three months duration. He had essential hypertension for the last four years and had a history of 25 pack-years of cigarettes smoking. His chest X-ray showed a left-sided mediastinal mass with mild to moderate pleural effusion. An ultrasound appeared to show an encysted pleural fluid collection. However, we proceeded with computed tomography before diagnostic thoracentesis. The diagnosis of Ortner’s syndrome was made after the computed tomography due to the silent rupture of his thoracoabdominal aortic aneurysm.

Conclusions

Hoarseness due to left recurrent laryngeal nerve palsy can be the presenting symptom of cardiovascular pathologies, Ortner’s syndrome. Silent rupture of thoracic aortic aneurysms can mimic that of thoracic malignancy, which is reported in literature. We illustrate the importance of a high degree of suspicion of cardiovascular pathology in order to avoid an adverse outcome following diagnostic thoracentesis.

Does lower limb exercise worsen renal artery hemodynamics in patients with abdominal aortic aneurysm?

Renal artery stenosis (RAS) and renal complications emerge in some patients after endovascular aneurysm repair (EVAR) to treat abdominal aorta aneurysm (AAA). The mechanisms for the causes of these problems are not clear. We hypothesized that for EVAR patients, lower limb exercise could negatively influence the physiology of the renal artery and the renal function, by decreasing the blood flow velocity and changing the hemodynamics in the renal arteries. To evaluate this hypothesis, pre- and post-operative models of the abdominal aorta were reconstructed based on CT images. The hemodynamic environment was numerically simulated under rest and lower limb exercise conditions. The results revealed that in the renal arteries, lower limb exercise decreased the wall shear stress (WSS), increased the oscillatory shear index (OSI) and increased the relative residence time (RRT). EVAR further enhanced these effects. Because these parameters are related to artery stenosis and atherosclerosis, this preliminary study concluded that lower limb exercise may increase the potential risk of inducing renal artery stenosis and renal complications for AAA patients. This finding could help elucidate the mechanism of renal artery stenosis and renal complications after EVAR and warn us to reconsider the management and nursing care of AAA patients.

Smoking, sex, risk factors and abdominal aortic aneurysms: a prospective study of 18 782 persons aged above 65 years in the Southern Community Cohort Study

BACKGROUND

Abdominal aortic aneurysm (AAA) is a leading cause of death in the USA. We evaluated the incidence and predictors of AAA in a prospectively followed cohort.

METHODS

We calculated age-adjusted AAA incidence rates (IR) among 18 782 participants aged ≥65 years in the Southern Community Cohort Study who received Medicare coverage from 1999-2012, and assessed predictors of AAA using multivariable Cox proportional hazards models, overall and stratified by sex, adjusting for demographic, lifestyle, socioeconomic, medical and other factors. HRs and 95% CIs were calculated for AAA in relation to factors ascertained at enrolment.

RESULTS

Over a median follow-up of 4.94 years, 281 cases were identified. Annual IR was 153/100,000, 401, 354 and 174 among blacks, whites, men and women, respectively. AAA risk was lower among women (HR 0.48, 95% CI 0.36 to 0.65) and blacks (HR 0.51, 95% CI 0.37 to 0.69). Smoking was the strongest risk factor (former: HR 1.91, 95% CI 1.27 to 2.87; current: HR 5.55, 95% CI 3.67 to 8.40), and pronounced in women (former: HR 3.4, 95% CI 1.83 to 6.31; current: HR 9.17, 95% CI 4.95 to 17). A history of hypertension (HR 1.44, 95% CI 1.04 to 2.01) and myocardial infarction or coronary artery bypass surgery (HR 1.9, 95% CI 1.37 to 2.63) was negatively associated, whereas a body mass index ≥25 kg/m(2) (HR 0.72; 95% CI 0.53 to 0.98) was protective. College education (HR 0.6, 95% CI 0.37 to 0.97) and black race (HR 0.44, 95% CI 0.28 to 0.67) were protective among men.

CONCLUSIONS

Smoking is a major risk factor for incident AAA, with a strong and similar association between men and women. Further studies are needed to evaluate benefits of ultrasound screening for AAA among women smokers.

Screening for abdominal aortic aneurysm during transthoracic echocardiography in patients with significant coronary artery disease

PURPOSE

Coronary artery disease (CAD) shares several risk factors with abdominal aortic aneurysm (AAA). We evaluated the prevalence during transthoracic echocardiography (TTE) and risk factors of AAA in patients with CAD.

MATERIALS AND METHODS

A total of 1300 CAD patients were screened from August 2009 to May 2010, and measurement of abdominal aorta size was feasible in 920 patients (71%) at the end of routine TTE. An AAA was defined as having a maximal diameter of ≥30 mm.

RESULTS

Of the 920 patients, 22 (2.4% of the study population) were diagnosed with AAA; of these AAA patients, 86% were male, and 82% were over 65 years-old. Abdominal aortic size was weakly correlated with aortic root diameter (r=0.22, p<0.01). Although the proportions of male gender, hypertension, and dyslipidemia were higher in AAA patients, such differences were not statistically significant. Advanced age [odds ratio (OR)=1.07; 95% confidence interval (CI): 1.01-1.12; p<0.01], smoking (OR=3.44; 95% CI: 1.18-10.04; p=0.02), and peripheral arterial disease (OR=5.88; 95% CI: 1.38-25.05; p=0.01) were found to be associated with AAA.

CONCLUSION

Although prevalence of AAA is very low in the Asian population, the prevalence of AAA in Asian CAD patients is higher than the general population. Therefore, opportunistic examination of the abdominal aorta during routine TTE could be effective, especially for male CAD patients over 65 years with a history of smoking or peripheral arterial disease.

Extracellular matrix defects in aneurysmal Fibulin-4 mice predispose to lung emphysema

Background

In this study we set out to investigate the clinically observed relationship between chronic obstructive pulmonary disease (COPD) and aortic aneurysms. We tested the hypothesis that an inherited deficiency of connective tissue might play a role in the combined development of pulmonary emphysema and vascular disease.

Methods

We first determined the prevalence of chronic obstructive pulmonary disease in a clinical cohort of aortic aneurysms patients and arterial occlusive disease patients. Subsequently, we used a combined approach comprising pathological, functional, molecular imaging, immunological and gene expression analysis to reveal the sequence of events that culminates in pulmonary emphysema in aneurysmal Fibulin-4 deficient (Fibulin-4^R) mice.

Results

Here we show that COPD is significantly more prevalent in aneurysm patients compared to arterial occlusive disease patients, independent of smoking, other clinical risk factors and inflammation. In addition, we demonstrate that aneurysmal Fibulin-4^R/R mice display severe developmental lung emphysema, whereas Fibulin-4^+/R mice acquire alveolar breakdown with age and upon infectious stress. This vicious circle is further exacerbated by the diminished antiprotease capacity of the lungs and ultimately results in the development of pulmonary emphysema.

Conclusions

Our experimental data identify genetic susceptibility to extracellular matrix degradation and secondary inflammation as the common mechanisms in both COPD and aneurysm formation.

[Risk evaluation of type B aortic dissection: importance for treatment of acute aortic syndrome]

Acute aortic syndrome (AAS) is a modern term used to describe interrelated emergency aortic conditions with similar clinical characteristics and challenges including aortic dissection, intramural hematoma (IMH) and penetrating aortic ulcer (PAU). Population-based studies suggest that the incidence of aortic dissection ranges from 2.6 to 3.5 cases per 100,000 inhabitants per year; hypertension and a variety of genetic disorders with altered connective tissue are the most prevalent risk conditions. In general, open surgical repair is recommended when dissection involves the ascending aorta, whereas medical management and endovascular stent graft repair is the best option when the ascending aorta is spared. Pathological conditions involving the aortic arch may be treated using a hybrid approach combining debranching of supra-aortic vessels and stent graft placement. Stent graft-induced remodeling of a dissected aorta seems to have long-term benefits in complicated and so-called uncomplicated type B dissections as almost every case reveals a risk profile and one in eight patients diagnosed with acute type B aortic dissection has either an IMH or a PAU. Pain is the most commonly presenting symptom of AAS and should prompt immediate attention including diagnostic imaging modalities, such as multislice computed tomography, transesophageal ultrasound and magnetic resonance imaging. A specific therapeutic approach is necessary for IMH and PAU because without treatment they have a very poor outcome, are unpredictable in evolution and can be more severe than acute aortic dissection. All patients must receive the best medical treatment available at admission. High-risk but asymptomatic patients with IMH and PAU can probably be monitored without interventions. All symptomatic patients will need treatment. In many of these patients a direct surgical approach is often prohibitive due to age and multiple comorbidities. Endovascular treatment offers superior results and is becoming a recognized indication for such patients. Irrespective of the treatment modality close surveillance is mandatory in order to monitor disease progression.

Acute dissection of the descending aorta: a case report and review of the literature

Cardiovascular disease is the leading cause of death worldwide. Acute aortic syndromes, which include aortic dissection, intramural hematoma, and penetrating aortic ulcer, represent the most morbid presentations of aortic disease and can be difficult to diagnose. Recent advances in imaging have allowed for more rapid and accurate diagnosis of acute aortic syndromes and the options for management are expanding. This case report and review presents the case of a 43-year-old man with acute type B aortic dissection who underwent two endovascular procedures for malperfusion syndrome. The review focuses on the presentation, diagnosis, medical management, and procedural options for acute dissection of the descending aorta.

Decreased expression of P54(nrb) /NonO correlates with collagen deposition and fibrosis in human aortic dissection

AIMS

Aortic dissection (AD) is characterized by changes in the extracellular matrix, including fibrosis with collagen production. P54(nrb) /NonO is known to be involved in collagen formation. In this study, we examined whether AD is associated with abnormal P54(nrb) /NonO expression.

METHODS AND RESULTS

Aortic specimens and serum were obtained from 10 patients with AD and 10 controls. In-vitro cultures of vascular smooth muscle cells (VSMCs) and adventitial fibroblasts (AFs) were obtained from organ donors. P54(nrb) /NonO protein and mRNA levels were determined by Western blot, immunohistochemistry and quantitative real-time reverse transcription-polymerase chain reaction (quantitative real-time RT-PCR). To evaluate collagen expression, we stained tissue sections with Masson's trichrome. Serum concentration of TNF-α was determined by enzyme-linked immunosorbent assay (ELISA). Aortic P54(nrb) /NonO protein and mRNA were decreased in AD patients, compared with controls. Decreased P54(nrb) /NonO mRNA correlated significantly with increased collagen deposition and fibrosis in AD aortas. In VSMCs and AFs from normal human aortas, P54(nrb) /NonO was expressed strongly and localized to the nucleus.

CONCLUSIONS

Patients with AD exhibited significantly decreased expression of P54(nrb) /NonO. The significant correlation between P54(nrb) /NonO and collagen may point to novel thinking about collagen metabolism research in AD aorta.

Interaction between widening of diameter of abdominal aorta and cardiovascular risk factors and atherosclerosis burden

The aim of this study was to investigate influence of traditional cardiovascular risk factors (CVRF) and subclinical atherosclerosis (ATS) burden on early stages of abdominal aortic diameter (AAD) widening among adults. 2,052 consecutive patients (P) (39 % women), mean age 52 ± 13 years, were prospectively screened for CVRF, ATS, and AAD. B-mode ultrasound was used to evaluate the largest AAD and to detect carotid and femoral atherosclerotic plaques. Mean AAD was 15.2 ± 2.8 mm. Atherosclerotic plaques were detected in 71 % of patients. Significant univariate correlation between AAD, traditional CVRF, and ABS was found. However, multiple regression analysis showed that only seven of them were significantly and weakly correlated with AAD (R² = 0.27, p < 0.001). On the other hand, a multivariate logistic analysis was used to evaluate CVRF impact on enlarged AAD ≥25 mm (EAAD) as compared to those with AAD <25 mm. These factors did not account for more than 30 % of interaction (R² = 0.30, p = 0.001). Furthermore, despite a large proportion of patients with high number of CVRF, and subclinical ATS, rate of patients with AAD ≥25 mm was low (1 %) and scattered regardless their CHD risk score or ATS burden. In conclusion, these results suggest that although some traditional CVRF and presence of ATS are associated with early stages of EAAD, other determinants still need to be identified for a better understanding of abdominal aortic aneurysm pathogenesis.

Current status of medical treatment for abdominal aortic aneurysm

Although cardiovascular disease is widely recognized as the leading cause of death, a lesser known fact is that aortic aneurysm is the 15th leading cause of death over the age of 65 years in the USA. The golden standard of the treatments are invasive interventions either with open surgical repair (OS) or endovascular aneurysm repair (EVAR). The concept of medical treatment is to prevent abdominal aortic aneurysm (AAA) from rupture and avoid surgical treatment by preventing aneurysm enlargement or even reducing aneurysm size. Matrix metalloproteinases (MMP) are structurally related metalloendopeptidases that can degrade the extracellular matrix and is thought to play important roles in AAA. There are many proposed pharmacological treatments including: β-blockers, angiotensin-converting enzyme inhibitor (ACE inhibitors), angiotensin-receptor blocker (ARB), statins, macrolides and, doxycycline, an inhibitor of the MMP. The latter is a potential promising drug as medical treatment for AAA and the Non-invasive Treatment of Abdominal Aortic Aneurysm Clinical Trial (N-TA(3)CT) is currently ongoing in the USA. Here, the pathophysiology and potential medical therapy for AAA will be reviewed.

In-hospital efficacy of endovascular aortic repair in patients with impending rupture versus contained rupture of abdominal aortic aneurysms

BACKGROUND

The purpose of our study was to compare the efficacy of endovascular aortic repair (EVAR) in patients with impending rupture of abdominal aortic aneurysm (IRAAA) versus contained rupture of abdominal aortic aneurysm (CRAAA).

METHODS

Of the 21 patients who underwent EVAR for infrarenal AAA from January 2009 to May 2011, 11 did so for IRAAA and 10 for CRAAA. We compared their demographic and aneurysmal characteristics, comorbidities, complications, and clinical outcomes during hospitalization.

RESULTS

The CRAAA group was younger than the IRAAA group. There were no group differences in AAA size, operation time, volume of contrast agent, length of hospital stay (LOHS), or preoperative LOHS. A small difference in mean intraoperative blood loss of ∼4 mL was noted, but was recognized as clinically insignificant. ICU stay and postoperative LOHS were greater in the CRAAA than in the IRAAA. One patient in the IRAAA group had a mild headache after EVAR. Four patients in the CRAAA group had postoperative complications: 1 had acute renal dysfunction; 1 had retroperitoneal infection; 1 had respiratory failure and myocardial infarction; and 1 died of respiratory tract infection and respiratory and cardiac failure.

CONCLUSIONS

Patients undergoing EVAR for CRAAA have a higher incidence of postprocedural severe complications and death than patients undergoing EVAR for IRAAA.

Cigarette smoke and inflammation: role in cerebral aneurysm formation and rupture

Smoking is an established risk factor for subarachnoid hemorrhage yet the underlying mechanisms are largely unknown. Recent data has implicated a role of inflammation in the development of cerebral aneurysms. Inflammation accompanying cigarette smoke exposure may thus be a critical pathway underlying the development, progression, and rupture of cerebral aneurysms. Various constituents of the inflammatory response appear to be involved including adhesion molecules, cytokines, reactive oxygen species, leukocytes, matrix metalloproteinases, and vascular smooth muscle cells. Characterization of the molecular basis of the inflammatory response accompanying cigarette smoke exposure will provide a rational approach for future targeted therapy. In this paper, we review the current body of knowledge implicating cigarette smoke-induced inflammation in cerebral aneurysm formation/rupture and attempt to highlight important avenues for future investigation.

A pictorial review of acute aortic syndrome: discriminating and overlapping features as revealed by ECG-gated multidetector-row CT angiography

Background

The term "acute aortic syndrome" (AAS) encompasses a spectrum of life-threatening conditions characterized by acute aortic pain. AAS traditionally embraces three abnormalities including classic aortic dissection, intramural haematoma, and penetrating atherosclerotic ulcer. Although the underlying etiologies and conditions predisposing to AAS are diverse, the clinical features are indistinguishable.

Methods

Multidetector-row computed tomography (CT) with electrocardiographic gating (ECG-gated MDCT) has greatly improved imaging of acute thoracic aortic diseases by virtually eliminating pulsation artifacts transmitted from cardiac motion and reveals subtle aortic abnormalities, which have been difficult to recognize by conventional non-gated CT.

Results

While these advances in imaging technology provide additional discriminating features of acute aortic diseases, they also reveal a range of overlapping features of these life-threatening conditions that not uncommonly are dynamic and evolving. These overlapping and transitional features may be a major source of misunderstanding, confusion, and controversy for diseases that cause AAS.

Conclusion

In this pictorial review, we describe the discriminating and typical imaging features as revealed by modern ECG-gated MDCT angiography. In addition to the discriminating features, recognition of the overlapping and transitional features in AAS will allow a more comprehensive understanding of their underlying pathophysiologic conditions and their natural history, and may improve therapeutic management.

Main Messages

• The superior visualization of ECG-gated CTA improves the diagnostic accuracy of acute aortic syndrome.

• ECG-gated CTA provides discriminating features of underlying pathophysiologic conditions of AAS.

• Also, recognition of the overlapping features in AAS will allow a more comprehensive understanding.

Biology of intracranial aneurysms: role of inflammation

Intracranial aneurysms (IAs) linger as a potentially devastating clinical problem. Despite intense investigation, our understanding of the mechanisms leading to aneurysm development, progression and rupture remain incompletely defined. An accumulating body of evidence implicates inflammation as a critical contributor to aneurysm pathogenesis. Intracranial aneurysm formation and progression appear to result from endothelial dysfunction, a mounting inflammatory response, and vascular smooth muscle cell phenotypic modulation producing a pro-inflammatory phenotype. A later final common pathway appears to involve apoptosis of cellular constituents of the vessel wall. These changes result in degradation of the integrity of the vascular wall leading to aneurysmal dilation, progression and eventual rupture in certain aneurysms. Various aspects of the inflammatory response have been investigated as contributors to IA pathogenesis including leukocytes, complement, immunoglobulins, cytokines, and other humoral mediators. Furthermore, gene expression profiling of IA compared with control arteries has prominently featured differential expression of genes involved with immune response/inflammation. Preliminary data suggest that therapies targeting the inflammatory response may have efficacy in the future treatment of IA. Further investigation, however, is necessary to elucidate the precise role of inflammation in IA pathogenesis, which can be exploited to improve the prognosis of patients harboring IA.

Aortic dissection after open repair of an infrarenal aortic aneurysm

INTRODUCTION

A case of thoracic-abdominal dissection after open surgical exclusion of an infrarenal aortic aneurysm is presented.

CASE PRESENTATION

A 62-year-old woman was diagnosed with an infrarenal abdominal aortic aneurysm with a rapid increase in maximal diameter. She underwent surgery for aneurysm exclusion by an end-to-end aortoaortic bypass with Dacron collagen (Intervascular; WL Gore & Associates Inc, USA). After 15 days, she was admitted to the emergency department with intense epigastric and lumbar pain. Computed tomography angiography with contrast revealed an aortic dissection with origin in the proximal bypass anastomosis and cranial extension to the thoracic aorta. The true lumen at the level of the eighth thoracic vertebra was practically collapsed by the false lumen. The celiac trunk, and the mesenteric and renal arteries were perfused by the true lumen. After the acute phase of the aortic dissection, surgical repair was planned. Two paths of false lumen were found - one at the thoracic aorta and the second in the proximal bypass anastomosis. Surgical repair comprised two approaches. First, a Valiant Thoracic stent graft (Medtronic Inc, UK) was implanted distal from the left subclavian artery, expanding the collapsed true lumen and covering the false and dissected lumen. Second, an infrarenal Endurant abdominal stent graft (Medtronic Inc) was implanted. This second device was complemented with an aortic infrarenal extension using a Talent abdominal stent graft (Medtronic Inc) in the infrarenal aortic neck to achieve a hermetic seal. The postoperative clinical course was uneventful, and her symptoms were completely resolved in six months.

CONCLUSION

Arteritis must be taken into account in young patients with high inflammatory markers. Covered stents and endoprosthetic devices seem to be effective methods to seal the dissected lumen.

Long term outcomes in men screened for abdominal aortic aneurysm: prospective cohort study

OBJECTIVE

To determine whether there is a relation between aortic diameter and morbidity and mortality in men screened for abdominal aortic aneurysm.

DESIGN

Prospective cohort study.

SETTING

Highland and Western Isles (a large, sparsely populated area of Scotland).

PARTICIPANTS

8146 men aged 65-74.

MAIN OUTCOME MEASURES

Morbidity and mortality in relation to presence of abdominal aortic aneurysm and three categories of aortic diameter (≤ 24 mm, 25-29 mm, and ≥ 30 mm).

RESULTS

When screened, 414 men (5.1%) had an aneurysm (diameter ≥ 30 mm), 669 (8.2%) an aortic diameter of 25-29 mm, and 7063 (86.7%) an aortic diameter of ≤ 24 mm. The cohort was followed up for a median of 7.4 (interquartile range 6.9-8.2) years. Mortality was significantly associated with aortic diameter: 512 (7.2%) men in the ≤ 24 mm group died compared with 69 (10.3%) in the 25-29 mm group and 73 (17.6%) in the ≥ 30 mm group. The mortality risk in men with an aneurysm or with an aorta measuring 25-29 mm was significantly higher than in men with an aorta of ≤ 24 mm. The increased mortality risk in the 25-29 mm group was reduced when taking confounders such as smoking and known heart disease into account. After adjustment, compared with men with an aortic diameter of ≤ 24 mm, the risk of hospital admission for cardiovascular disease and chronic obstructive pulmonary disease was significantly higher in men with aneurysm and those with aortas measuring 25-29 mm. Men with an aneurysm also had an increased risk of hospital admission for cerebrovascular disease, atherosclerosis, peripheral arterial disease, and respiratory disease. In men with aortas measuring 25-29 mm, the risk of hospital admission with abdominal aortic aneurysm was significantly higher than in men with an aorta of ≤ 24 mm (adjusted hazard ratio 6.7, 99% confidence interval 3.4 to 13.2) and this increased risk became apparent two years after screening.

CONCLUSIONS

Men with abdominal aortic aneurysm and those with aortic diameters measuring 25-29 mm have an increased risk of mortality and subsequent hospital admissions compared with men with an aorta diameter of ≤ 24 mm. Consideration should be given to control of risk factors and to rescreening men with aortas measuring 25-29 mm at index scanning.

Associations between serum lipoprotein(a) levels and the severity of coronary and aortic atherosclerosis

To elucidate the associations between Lp(a) levels and coronary and aortic atherosclerosis, we performed aortic MRI in 143 patients undergoing coronary angiography. Severity of aortic atherosclerosis was represented as plaque scores. Of the 143 patients, 104 had coronary artery disease (CAD). Thoracic and abdominal aortic plaques were found in 89 and 131 patients. Lp(a) levels increased stepwise with the number of stenotic coronary vessels: 15.7 (CAD(-)), 21.2 (1-vessel), 21.4 (2-vessel), and 22.9 mg/dl (3-vessel) (P<0.05). For aortic atherosclerosis, 143 patients were divided into quartiles by plaque scores. Lp(a) did not differ among quartiles of thoracic plaques: 17.1, 19.0, 23.5, and 21.2 mg/dl (P=NS), whereas Lp(a) increased stepwise with quartiles of abdominal plaques: 17.1, 19.2, 19.1, and 24.0 mg/dl (P<0.05). Lp(a) was an independent factor for CAD and abdominal aortic plaques, but not thoracic plaques. Thus, Lp(a) levels were associated with aortic atherosclerosis, especially in abdominal aorta, as well as coronary atherosclerosis.

A case of multiple giant coronary aneurysms and abdominal aortic aneurysm coexisting with IgG4-related disease

IgG4-related disease (IgG4RD) is a unique systemic lymphoproliferative disorder characterized by elevated serum IgG4 levels and IgG4-producing plasma cell expansion in the affected tissues, which are accompanied by fibrotic or sclerotic changes. Vascular lesions may also be a part of IgG4RD as a number of case reports have discussed inflammatory abdominal aortic aneurysms associated with IgG4RD, but coronary artery lesions seem to be rare complications of IgG4RD. A 71-year-old man suffered from multiple giant coronary aneurysms and an abdominal aortic aneurysm with concurrent pancreatic, gall bladder, bile duct, and salivary gland lesions resulting from IgG4RD. The present observations suggest that coronary aneurysms may also develop as a consequence of this disease.

Analysis of the molecular mobility of collagen and elastin in safe, atheromatous and aneurysmal aortas

AIM OF THE STUDY

In this study, we propose to use a thermal technique, Differential Scanning Calorimetry (DSC) to follow the evolution of elastin and collagen in safe and pathological cardiovascular tissues.

PATIENTS AND METHODS

The first part of this study deals with the analysis of the elastin network and associated proteins during ageing (from children to old persons) in aortic walls. The second part is devoted to the characterization of the collagenic phase in aneurysms. In both cases, physical data are correlated with biochemical analyses.

RESULTS AND CONCLUSION

For old persons aortas with atheromatous stades, elastin and associated proteins are found to interpenetrate to form a homogenous phase. Abdominal aortic aneurysms (AAA) are characterized by structural alterations of the aortic wall resulting from the degradation of elastic fibers and an increase of collagen/elastin ratio. Notable modifications are evidenced between collagen from control tissue and collagen from AAA, particularly concerning the thermal denaturation. Biochemical and thermal results are compatible with the increase of new collagen deposition and/or impairment of the collagen phase stability in the extracellular matrix of AAAs.

Differential roles of endothelin-1 in angiotensin II-induced atherosclerosis and aortic aneurysms in apolipoprotein E-null mice

Because both endothelin-1 (ET-1) and angiotensin II (AngII) are independent mediators of arterial remodeling, we sought to determine the role of ET receptor inhibition in AngII-accelerated atherosclerosis and aortic aneurysm formation. We administered saline or AngII and/or bosentan, an endothelin receptor antagonist (ERA) for 7, 14, or 28 days to 6-week- and 6-month-old apolipoprotein E-knockout mice. AngII treatment increased aortic atherosclerosis, which was reduced by ERA. ET-1 immunostaining was localized to macrophage-rich regions in aneurysmal vessels. ERA did not prevent AngII-induced aneurysm formation but instead may have increased aneurysm incidence. In AngII-treated animals with aneurysms, ERA had a profound effect on the non-aneurysmal thoracic aorta via increasing wall thickness, collagen/elastin ratio, wall stiffness, and viscous responses. These observations were confirmed in acute in vitro collagen sheet production models in which ERA inhibited AngII's dose-dependent effect on collagen type 1 α 1 (COL1A1) gene transcription. However, chronic treatment reduced matrix metalloproteinase 2 mRNA expression but enhanced COL3A1, tissue inhibitor of metalloproteinase 1 (TIMP-1), and TIMP-2 mRNA expressions. These data confirm a role for the ET system in AngII-accelerated atherosclerosis but suggest that ERA therapy is not protective against the formation of AngII-induced aneurysms and can paradoxically stimulate a chronic arterial matrix remodeling response.

In vivo evaluation of a new magnetic resonance imaging contrast agent (P947) to target matrix metalloproteinases in expanding experimental abdominal aortic aneurysms

OBJECTIVE

Abdominal aortic aneurysm (AAA) rupture is a devastating event, and development of noninvasive methods to detect AAA at risk is needed. Matrix metalloproteinases (MMPs) play a major role in AAA growth and their subsequent rupture. This study was aimed to evaluate the ability of P947, a recently developed magnetic resonance imaging (MRI) contrast agent, to target MMPs in vivo in expanding experimental AAAs.

MATERIALS AND METHODS

AAAs were induced in Wistar rats (n = 18) by perfusion of a segment of the abdominal aorta with porcine elastase. After 5 or 6 days of elastase perfusion, when the aortic segment was expanding and showed inflammation with high MMP levels, rats were injected either with P947 (n = 6), P1135, a scramble form of P947 (n = 6), or with the reference contrast agent Gadolinium-DOTA (Gd-DOTA) (n = 3). Sham-operated rats (n = 3) were injected with P947 as controls. Imaging was performed on the animals using a 1.5T MRI scanner before and at different times after injection of contrast agents (100 μmol/kg). Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) gelatin zymography of culture media conditioned by incubation with perfused aortic segment or control TA from elastase-perfused rats (n = 3) was performed to determine levels of MMP2 and MMP9. In addition, in situ gelatin zymography was used to localize these active MMPs on frozen histologic sections.

RESULTS

The normalized signal enhancement determined on MRI images was higher in the perfused aortic segment of rats injected with P947 (162%) than in rats injected with P1135 (100%) or Gd-DOTA (117%) (P < 0.01 using the Friedman test) from 5 to 125 minutes after injection. The area of contrast enhancement on MRI images colocalized with the fluorescence generated by MMPs in the AAA inflammatory area, as detected by in situ zymography on histologic sections.

CONCLUSION

Our data showed that MRI using P947 allows detection of MMP activity within the inflammatory wall of experimental AAAs, thus representing a potential noninvasive method to detect AAAs with a high risk of rupture.

Causes and histopathology of ascending aortic disease in children and young adults

BACKGROUND

Ascending aortic diseases (aneurysms, dissections, and stenosis) and associated aortic valve disease are rare but important causes of morbidity and mortality in children and young adults. Certain genetic causes, such as Marfan syndrome and congenital bicuspid aortic valve disease, are well known. However, other rarer genetic and nongenetic causes of aortic disease exist.

METHODS

We performed an extensive literature search to identify known causes of ascending aortic pathology in children and young adults. We catalogued both aortic pathologies and other defining systemic features of these diseases.

RESULTS

We describe 17 predominantly genetic entities that have been associated with thoracic aortic disease in this age group.

CONCLUSIONS

While extensive literature on the common causes of ascending aortic disease exists, there is a need for better histologic documentation of aortic pathology in rarer diseases.

The role of the renin-angiotensin system in thoracic aortic aneurysms: clinical implications

Thoracic aortic aneurysms (TAAs) are a potential life-threatening disease with limited pharmacological treatment options. Current treatment options are aimed at lowering aortic hemodynamic stress, predominantly with β-adrenoceptor blockers. Increasing evidence supports a role for the renin-angiotensin system (RAS) in aneurysm development. RAS blockade would not only lower blood pressure, but might also target the molecular pathways involved in aneurysm formation, in particular the transforming growth factor-β and extracellular signal-regulated kinase 1/2 pathways. Indeed, the angiotensin II type 1 (AT₁) receptor blocker losartan was effective in lowering aortic root growth in mice and patients with Marfan's syndrome. RAS inhibition (currently possible at 3 levels, i.e. renin, ACE and the AT₁ receptor) is always accompanied by a rise in renin due to interference with the negative feedback loop between renin and angiotensin II. Only during AT₁ receptor blockade will this result in stimulation of the non-blocked angiotensin II type 2 (AT₂) receptor. This review summarizes the clinical aspects of TAAs, provides an overview of the current mouse models for TAAs, and focuses on the RAS as a new target for TAA treatment, discussing in particular the possibility that AT₂ receptor stimulation might be crucial in this regard. If true, this would imply that AT₁ receptor blockers (and not ACE inhibitors or renin inhibitors) should be the preferred treatment option for TAAs.

Aortic atherosclerosis predicts the extent and severity of coronary atherosclerosis detected by multidetector computed tomography coronary angiography

We investigated the association between atherosclerosis of the thoracic aorta and the severity and extent of coronary atherosclerosis detected by multidetector computed tomography (MDCT) coronary angiography. In 122 patients, atherosclerotic plaque was scored from 0 to 4 points by the percentage of the luminal surface at the cross-sectional area of proximal, mid, and distal segments of the descending aorta. Critical coronary atherosclerosis was defined as lesions causing >50% luminal narrowing. Atherosclerotic plaque score of the descending aorta was associated with the severity (noncritical: 2.95 +/- 1.45 vs critical: 4.09 +/- 2.25, P < .001) and extent of coronary atherosclerosis (Kruskal-Wallis test, P < .005). Logistic regression revealed that aortic plaque score was as an independent risk factor associated with the severity of coronary artery disease (OR 1.32, 95% CI 1.01-1.73, P <.05). Atherosclerotic plaque burden of the descending aorta was associated with the extent and severity of coronary atherosclerosis.

Genetic and epigenetic mechanisms and their possible role in abdominal aortic aneurysm

Abdominal aortic aneurysm (AAA) is a common disease associated with significant cardiovascular morbidity and mortality. The pathogenesis of AAA is poorly defined, making targeting of new therapies problematic. Current evidence favours an interaction of multiple environmental and genetic factors in the initiation and progression of AAA. Epigenetics is the term used to define the properties of the genome that are not explained by the primary sequence, but are due to the modifications of DNA and/or associated proteins. Previous research indicates the association of gene specific promoter DNA hyper-methylation and global DNA hypo-methylation with atherosclerosis. Evidence also suggests an important role for epigenetic processes such as histone acetylation in cardiovascular diseases including atherosclerosis and restenosis. Altered DNA methylation or histone acetylation occur in inflammation, cellular proliferation and remodelling processes and therefore maybe relevant to the pathology of AAA. Important risk factors for AAA, including cigarette smoking, older age, male gender and hypertension, have been linked with epigenetic effects and thus could act in this way to promote AAA. In this review, we discuss the potential role of epigenetic mechanisms in AAA. Since epigenetic alterations are to some extent reversible, further study of this area may identify new treatment targets for AAA.

Variations in atherosclerosis and remodeling patterns in aorta and carotids

BACKGROUND

Atherosclerosis is a progressive disease that causes vascular remodeling that can be positive or negative. The evolution of arterial wall thickening and changes in lumen size under current "standard of care" in different arterial beds is unclear. The purpose of this study was to examine arterial remodeling and progression/regression of atherosclerosis in aorta and carotid arteries of individuals at risk for atherosclerosis normalized over a 1-year period.

METHODS

In this study, 28 patients underwent at least 2 black-blood in vivo cardiovascular magnetic resonance (CMR) scans of aorta and carotids over a one-year period (Mean 17.8 +/- 7.5 months). Clinical risk profiles for atherosclerosis and medications were documented and patients were followed by their referring physicians under current "standard of care" guidelines. Carotid and aortic wall lumen areas were matched across the time-points from cross-sectional images.

RESULTS

The wall area increased by 8.67%, 10.64%, and 13.24% per year (carotid artery, thoracic aorta and abdominal aorta respectively, p < 0.001). The lumen area of the abdominal aorta increased by 4.97% per year (p = 0.002), but the carotid artery and thoracic aorta lumen areas did not change significantly. The use of statin therapy did not change the rate of increase of wall area of carotid artery, thoracic and abdominal aorta, but decreased the rate of change of lumen area of carotid artery (-3.08 +/- 11.34 vs. 0.19 +/- 12.91 p < 0.05).

CONCLUSIONS

Results of this study of multiple vascular beds indicated that different vascular locations exhibited varying progression of atherosclerosis and remodeling as monitored by CMR.