[Sudden deaths due to non-traumatic aortic aneurysms rupture]

In this work we review two cases of ruptured aortic aneurysms which arose from congenital abnormalities of the aortic wall structure. In the first case, a 16-year old, previously untreated boy died, with no previous symptoms of an aortic aneurysm. The boy was suspected of taking drugs and even of committing suicide. A young couple found the boy's body in the wood close to the bus stop. There were no signs of violence on the corpse and the body was fully and properly dressed. The autopsy revealed enlarged (true aneurysm) and ruptured ascending aorta with about 700 ml of blood in the pericardial sac. Toxicological examination was negative. Histopathology showed abnormalities in the structure of the wall of aorta in the place of the rupture. All other body organs and vessels seemed to be normal and properly developed except the thoracic aorta, and no other morphologic abnormalities were present. In the second case, the corpse of a 30-year-old man was found in his apartment (he lived with his parents). The parents claimed he did not use drugs or alcohol. The autopsy, as in the previous case, revealed a ruptured true aneurysm of the ascending aorta with 370 g of blood in the pericardial sac. The concaved thoracic cavity was also observed. After the autopsy, the man's parents reported that in childhood, their son was diagnosed to suffer from Marfan syndrome.

Angiotensin II type 2 receptor signaling attenuates aortic aneurysm in mice through ERK antagonism

Angiotensin II (AngII) mediates progression of aortic aneurysm, but the relative contribution of its type 1 (AT1) and type 2 (AT2) receptors remains unknown. We show that loss of AT2 expression accelerates the aberrant growth and rupture of the aorta in a mouse model of Marfan syndrome (MFS). The selective AT1 receptor blocker (ARB) losartan abrogated aneurysm progression in the mice; full protection required intact AT2 signaling. The angiotensin-converting enzyme inhibitor (ACEi) enalapril, which limits signaling through both receptors, was less effective. Both drugs attenuated canonical transforming growth factor-β (TGFβ) signaling in the aorta, but losartan uniquely inhibited TGFβ-mediated activation of extracellular signal-regulated kinase (ERK), by allowing continued signaling through AT2. These data highlight the protective nature of AT2 signaling and potentially inform the choice of therapies in MFS and related disorders.

Ruptured sinus of Valsalva aneurysm in a child with Down syndrome: a rare cardiac anomaly

BACKGROUND

As many as forty to fifty per cent of children with Down syndrome are born with a cardiac anomaly. Sinus of Valsalva aneurysm in this syndrome is extremely rare, only three previous reports, and of adult onset.

CASE REPORT

An asymptomatic 9 and a half year boy with Down syndrome presented with a cardiac murmur at routine examination. Clinical examination, transthoracic and transesopahageal echocardiography revealed the presence of a ruptured sinus of Valsalva aneurysm from the non - coronary sinus protruding into the right atrium. The child underwent successful surgical repair with full recovery.

CONCLUSIONS

This fourth case report of sinus of Valsalva aneurysm occurring in association with Down syndrome is the youngest to date. Physicians caring for Down syndrome patients ought to be aware of this late onset cardiac malformation. Serial echocardiographic assessment of the aortic sinus of Valsalva in these patients may offer early detection.

Quantitative assessment of abdominal aortic aneurysm geometry

Recent studies have shown that the maximum transverse diameter of an abdominal aortic aneurysm (AAA) and expansion rate are not entirely reliable indicators of rupture potential. We hypothesize that aneurysm morphology and wall thickness are more predictive of rupture risk and can be the deciding factors in the clinical management of the disease. A non-invasive, image-based evaluation of AAA shape was implemented on a retrospective study of 10 ruptured and 66 unruptured aneurysms. Three-dimensional models were generated from segmented, contrast-enhanced computed tomography images. Geometric indices and regional variations in wall thickness were estimated based on novel segmentation algorithms. A model was created using a J48 decision tree algorithm and its performance was assessed using ten-fold cross validation. Feature selection was performed using the χ2-test. The model correctly classified 65 datasets and had an average prediction accuracy of 86.6% (κ=0.37). The highest ranked features were sac length, sac height, volume, surface area, maximum diameter, bulge height, and intra-luminal thrombus volume. Given that individual AAAs have complex shapes with local changes in surface curvature and wall thickness, the assessment of AAA rupture risk should be based on the accurate quantification of aneurysmal sac shape and size.

Arterial elastic fiber structure. Function and potential roles in acute aortic dissection

The lethality of acute aortic dissection is well recognized. Successful treatment and prevention of aortic dissection is going to be dependent upon an improved understanding of the molecular and physiologic events which predispose to dissection development and propagation. In this review, we will focus on the elastic fiber, one of the critical elements of the aortic wall matrix. Mechanical or functional failure of the elastin in the wall of the aorta likely predisposes to dissection as well as the post-dissection aortic degeneration with aneurysm formation. Insight into the role of the elastin and the elastic fiber in aortic dissection has recently been accelerated by research into the molecular mechanisms associated with hereditary propensity for aortic dissection, such as Marfan syndrome. These studies have implicated both structural and metabolic contributions of alterations in the scaffolding proteins in matrix elastic fibers. In particular, increased transforming growth factor-β (TGF-β) activity may play a prominent role in predisposing the aortic wall to dissection. The events which predispose to post-dissection aortic degeneration are somewhat less well defined. However, the loss of the structural integrity of the remaining elastic fibers leaves the wall weaker and prone to dilatation and rupture. It appears likely that the upregulation of several potent proteases, particularly those of the matrix metalloproteinase (MMP) family such as MMP-9, are participating in the subsequent matrix damage. Novel medical treatments based on this pathologic data have been proposed and in some cases have made it to clinical trials. The ongoing study evaluating whether therapeutic inhibition of TGF-β may be useful in reducing the risk of aortic dissection in patients at high risk represents one promising new strategy in the treatment of this deadly disease.

Aortic intramural hematoma associated with metastatic carcinoma

We present a case of aortic intramural hematoma, a variant of aortic dissection, with metastatic carcinoma invasion within the aortic wall and pseudolumen. An elderly male patient with a history of controlled hypertension initially experienced chest pain. A computed tomographic scan revealed aortic intramural hematoma; thus, conservative therapy was performed. One and a half months later, tumors in both adrenal glands and the lumbar vertebra were discovered. The primary site was not identified, and the patient died following septic shock 1 month later. An autopsy revealed intramural hematoma throughout the aorta, as well as systemic metastases of adrenocortical carcinoma with invasion into the aortic wall and formation of a pseudolumen accompanied by disruption of the vasa vasorum. As far as we know, this is the second case of aortic dissection associated with metastatic carcinoma. The highly aggressive nature of the tumor cells was demonstrated by high mitotic ratio and Ki-67 labeling index. The tumor was also positive for matrix metalloproteinase-12, thus suggesting disruption of the aortic media.

[Sudden/unexpected death due to spontaneous aortic rupture: two unusual manifestation forms]

Sudden unexpected death from a natural (pathological) cause often occurs under suspicious circumstances suggesting foreign intervention, so that a forensic autopsy is deemed necessary. In adults, a significant share of these deaths is due to spontaneous ruptures of the aorta. In figures, dissections of the ascending aorta and the aortic arch (mostly associated with secondary perforation into the pericardium) account for a large percentage followed by arteriosclerotic aneurysms of the abdominal aorta (with retroperitoneal and sometimes intraperitoneal hemorrhage). The authors report on two fatal aortic ruptures in which the hemorrhage showed an unusual route to spread. In the first case an 80-year-old man with an arteriosclerotic aneurysm of the abdominal aorta died from acute intestinal bleeding via an aortojejunal fistula. In a 42-year-old man, a dissecting hemorrhage in the wall of the aortic arch resulted in the compression of the branching sites of the brachiocephalic trunk, the left common carotid artery and the left subclavian artery, while the volume of blood in the pericardium was rather small (60 ml). On the basis of these examples, the medicolegal aspects of spontaneous aortic ruptures are discussed.

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.

Circulatory arrest in late pregnancy: caesarean section a vital decision for both mother and child

Circulatory arrest during pregnancy is extremely rare and there should be a well-planned strategy for its management in all hospitals. To consider the priority of the mother's life over the child's and an unwarranted pre-term delivery may lead to hesitancy and uncertainty and jeopardize both of them. In these situations, speed is a priority. Cardiopulmonary resuscitation should commence immediately. The anaesthesiologist should be well aware of the possible advantage of a caesarean section. Even if the obstetrician is responsible for the decision to perform the operation, the anaesthesiologist should strongly support the action. An 'emergency caesarean kit' with the essential surgical instruments should be immediately available in every labour ward and emergency department.

Maximum aortic diameter as a simple predictor of acute type B aortic dissection

OBJECTIVES

To identify the most prognostic predictor of Stanford type B aortic dissection at admission.

PATIENTS AND METHODS

Forty-three patients with Stanford type B aortic dissection were divided into two groups: (1) those who developed dissection-related events later (EV group: n = 18), including the need for surgery (n = 12), rupture (n = 1), dissection-related death (n = 5), and aortic enlargement > or =5 mm in diameter per year (n = 15); (2) those without later events (NoEV group: n = 25). Clinical features, aortic diameters, and blood flow status were compared.

RESULTS

The maximum aortic diameter at admission was 41.5 +/- 1.7 mm for the EV group, which was significantly greater than the NoEV group (34.4 +/- 0.9 mm, p <0.001). A maximum aortic diameter > or =40 mm was found in 11 patients (61%) of the EV group, whereas this maximum was found in 4 (16%) of the NoEV group (p = 0.004). A patent false lumen at admission was found in all patients of the EV group and in 17 (68%) of the NoEV group (p = 0.013). Other factors were not significant. A Cox hazard analysis indicated a maximum aortic diameter > or =40 mm as a significant predictor for dissection-related events (hazard ratio 3.13, p = 0.032). The presence of a patent false lumen did not reach a statistical significance.

CONCLUSION

Our results indicated that a maximum aortic diameter > or =40 mm at admission was the most prognostic factor for developing late dissection-related events, rather than the presence of a patent false lumen.

Asymptomatic spontaneous rupture of a nonaneurismal visceral aorta

Spontaneous nonaneurysmal rupture of the aorta is a life-threatening condition for which emergency diagnostic and therapeutic measures are indicated. An asymptomatic spontaneous aortic rupture was unexpectedly discovered adjacent to the visceral aorta. We diagnosed the mass as a pseudoaneurysm, and surgery was performed. This was the first reported case of asymptomatic spontaneous rupture of a nonaneurysmal visceral aorta.

Aortic dissection and its endovascular management

Aortic dissection is the commonest life-threatening event involving the aorta, affecting 5-10 per million people per year. Without treatment, half of patients with acute proximal aortic dissections die within 24 hours, and 60% of patients with acute distal aortic dissections die within 1 month. Only 10% of patients with proximal dissections and 40% of those with distal dissections will be alive at 1 year. Patients with chronic distal dissections are at risk of aortic rupture with nearly 20% requiring intervention. The aim of management of aortic dissection is to reduce propagation of the dissection plane and prevent the fatal complications of this condition. A paradigm shift in the surgical management of these patients began in the late 1990s with the reporting of two small series of patients being treated with custom-designed covered stents delivered through a unilateral arteriotomy. Both studies demonstrated the feasibility and technical success in endovascular sealing of the proximal intimal entry tear in patients with type B thoracic dissections.

[Ruptured proximal aorta after operation for type A dissection presenting as opacified left hemothorax; report of a case]

We report an unusual clinical presentation of ruptured proximal aorta as a left hemothorax after operation for type A dissection. A 74-year-old man who had undergone ascending aortic replacement for acute type A dissection 4 months previously developed a loss of consciousness followed by shock state. Both chest X-ray and computed tomography (CT) scan revealed opacified left hemothorax. The patient died during a diagnostic procedure. Post mortem examination showed rupture of proximal aortic dissection extended to the left pleural cavity path through the right atrial wall and the right ventricular wall.

Doxycycline delays aneurysm rupture in a mouse model of Marfan syndrome

OBJECTIVES

Thoracic aneurysms are the main cardiovascular complication of Marfan syndrome (MFS) resulting in premature death. MFS has been associated with mutations of the gene encoding fibrillin-1 (FBN1), a major constituent of the elastic fibers. Matrix metalloproteinases (MMPs) are important in the pathogenesis of abdominal aortic aneurysms but their precise role in MFS is not clear. Doxycycline is a nonspecific MMP inhibitor. The objective of the study was to determine whether docycycline can attenuate matrix degradation and prolong the survival of mice with MFS.

METHODS

The study employed a well-characterized animal model of MFS, namely fibrillin-1 under-expressing mice (mgR/mgR mice) that die spontaneously from rupture of the thoracic aorta between 2 to 4 months of age. Mutant and wild type mice were given doxycycline in their drinking water at a concentration designed to provide 100 mg/kg/day beginning at postnatal day (PD) 1, whereas control mice were given water. Treated mice were divided into two groups. One group of animals was followed until death or for 7 months to determine lifespan. In the second group of mice, the ascending thoracic aortas were collected for histological analysis (H&E staining, trichrome staining) and zymography for examining MMP-2 and MMP-9 levels at 6 weeks.

RESULTS

MMP-2 and MMP-9 levels were higher in the thoracic aorta of mgR/mgR mice compared with wild type littermates. Doxycycline-treated mgR/mgR mice lived 132 +/- 14.6 days (n = 16) or significantly longer than untreated mutant mice (79 +/- 6.7 days, n = 30) (P < 0.01). Connective tissue staining showed that doxycycline treatment decreased elastic fiber degradation in mgR/mgR mice. Furthermore, mgR/mgR mice treated with doxycycline had lower MMP-2 and MMP-9 levels compared with untreated mgR/mgR mice.

CONCLUSIONS

This study demonstrates that doxycycline significantly delays aneurysm rupture in MFS-like mice by inhibiting expression of tissue MMP-2 and MMP-9 and thus, degradation of the elastic matrix. The results suggest that MMPs contribute to the progression of thoracic aneurysm in MFS and that doxycycline has the potential to significantly alter the course of the disease.

Kernohan's phenomenon associated with left ruptured occipital arteriovenous malformation

A 23-year-old woman presented with ipsilateral hemiparesia due to rupture of a left occipital arteriovenous malformation (AVM). Emergency decompression (the onset-operation interval was 46 minutes,) was carried out and the patient could leave the hospital upon recovery without neurological deficits. In general, Kernohan's phenomenon is caused by the gradual displacement of the cerebral peduncle against the tentorial edge caused by compression by the contralateral mass. This phenomenon is very rare among the cases with spontaneous intracranial hemorrhage and only three cases including the present one have been reported in the literature. In all cases the onset-operation intervals of were very short. Kernohan's phenomenon associated with a ruptured AVM is a rare condition and emergency decompression is required.

The development of abdominal aortic aneurysms in mice is enhanced by benzo(a)pyrene

Cigarette smoking has been strongly associated with abdominal aortic aneurysm (AAA), but the components of tobacco smoke involved in AAA have not been identified. Benzo(a)pyrene (BaP) is an important constituent in cigarette smoke capable of induction of alterations strikingly similar to the pathological changes seen during AAA development. We therefore hypothesized that BaP exposure contributes to the development of AAA. In this study, C57/B6J mice were treated with vehicle, angiotensin II (AngII) (0.72 mg/kg/day), BaP (10 mg/kg/week), or the combination of AngII and BaP, for 5 weeks, and then examined for incidence of AAA and pathological changes of the aortic wall. Results showed that incidence of AAA formation in C57/B6J mice treated with BaP and AngII was significantly higher than that in AngII-treated mice (7 of 12 compared to 2 of 12). Further, five mice in the group treated with AngII/BaP and one in the group treated with AngII exhibited AAA rupture and hematoma. BaP caused macrophage infiltration, disarray of elastic lamella, and loss of vascular smooth muscle cells (VSMCs). We conclude that BaP aggravates AAA formation and rupture in C57/B6J mice by promoting macrophage infiltration, degeneration of elastic lamella, and loss of VSMCs in the aortic wall.

Medical Management of Abdominal Aortic Aneurysm

Medical management of patients with abdominal aortic aneurysm (AAA) is required for several different reasons. Since these patients have an increased risk of cardiovascular death therapy to reduce cardiovascular events is essential. Treatment is in line with the medical management of coronary artery disease including smoking cessation, statins and anti-platelet therapy. Some of these therapies also will slow aneurysm growth. Currently there is no proven focused therapy that reduces aneurysm growth, but the emerging strategies are discussed. Medical management also is required to reduce peri-operative risks and stabilise endovascular aneurysm repair. Whilst some of the therapies targeting cardiovascular risk reduction may be helpful, other emerging strategies are discussed.