Ruptured abdominal aortic aneurysm with aorto-caval fistula

Editor's Choice -- European Society for Vascular Surgery (ESVS) 2024 Clinical Practice Guidelines on the Management of Abdominal Aorto-Iliac Artery Aneurysms

OBJECTIVE

The European Society for Vascular Surgery (ESVS) has developed clinical practice guidelines for the care of patients with aneurysms of the abdominal aorta and iliac arteries in succession to the 2011 and 2019 versions, with the aim of assisting physicians and patients in selecting the best management strategy.

METHODS

The guideline is based on scientific evidence completed with expert opinion on the matter. By summarising and evaluating the best available evidence, recommendations for the evaluation and treatment of patients have been formulated. The recommendations are graded according to a modified European Society of Cardiology grading system, where the strength (class) of each recommendation is graded from I to III and the letters A to C mark the level of evidence.

RESULTS

A total of 160 recommendations have been issued on the following topics: Service standards, including surgical volume and training; Epidemiology, diagnosis, and screening; Management of patients with small abdominal aortic aneurysm (AAA), including surveillance, cardiovascular risk reduction, and indication for repair; Elective AAA repair, including operative risk assessment, open and endovascular repair, and early complications; Ruptured and symptomatic AAA, including peri-operative management, such as permissive hypotension and use of aortic occlusion balloon, open and endovascular repair, and early complications, such as abdominal compartment syndrome and colonic ischaemia; Long term outcome and follow up after AAA repair, including graft infection, endoleaks and follow up routines; Management of complex AAA, including open and endovascular repair; Management of iliac artery aneurysm, including indication for repair and open and endovascular repair; and Miscellaneous aortic problems, including mycotic, inflammatory, and saccular aortic aneurysm. In addition, Shared decision making is being addressed, with supporting information for patients, and Unresolved issues are discussed.

CONCLUSION

The ESVS Clinical Practice Guidelines provide the most comprehensive, up to date, and unbiased advice to clinicians and patients on the management of abdominal aorto-iliac artery aneurysms.

Treatment of Aortocaval Fistula Secondary to Abdominal Aortic Aneurysm: A Systematic Review

BACKGROUND

Aortocaval fistula (ACF) secondary to an abdominal aortic aneurysm is a rare complication, inadvertently caused by a rupture into the inferior vena cava. Different treatment modalities have been applied toward the repair of such lesions, including open surgical and endovascular repair. The aim of this study was to report on ACF treatment and to analyze its early and mid-term outcomes.

METHODS

A systematic search of the English medical literature published between 2000 and 2022 was undertaken, using PubMed, SCOPUS, and CENTRAL databases as per the Preferred Reporting Items for Systematic Reviews and Meta-Analysis 2020 guidelines. A study protocol was registered in PROSPERO (CRD42022329058). Studies reporting on primary ACF outcomes following open surgical or endovascular repair were included. The ROBINS-I tool was applied for risk of bias assessment. Outcomes included technical success, 30-day and mid-term survival, endoleak following endovascular repair, and reintervention rates.

RESULTS

In total, 110 case studies, incorporating 196 patients (mean age; 66.2 years, males 96%) were included. Open surgical repair was applied in 78% (153/196). From the available data, technical success rate for each modality was 99% (152/153) and 100% (43/43), respectively. Open and endovascular repair demonstrated 87.5% (126/144) and 97.6% (42/43) 30-day survival, respectively, while mid-term survival was 86% (74/86) and 95.2% (20/21), respectively (medial follow-up: 14 months [1-54 months]). Endoleaks were reported in 19 endovascular cases (39.5%). Type II endoleak was the most frequent with a rate at 32.5% (14/43). Reintervention rates were 2.5% (4/151) and 35.7% (15/42) for open and endovascular repair, respectively.

CONCLUSIONS

Only few case studies were published on the treatment of this rare condition, while almost all invasive procedures were performed in males. Management of ACF repair with both open and endovascular approach was associated with excellent technical success rate and acceptable early and mid-term survival outcomes. Reintervention remained an issue for patients who were managed endovascularly.

Structurally abnormal collagen fibrils in abdominal aortic aneurysm resist platelet adhesion

BACKGROUND

Platelet adhesion to the subendothelial collagen fibrils is one of the first steps in hemostasis. Understanding how structural perturbations in the collagen fibril affect platelet adhesion can provide novel insights into disruption of hemostasis in various diseases. We have recently identified the presence of abnormal collagen fibrils with compromised D-periodic banding in the extracellular matrix remodeling present in abdominal aortic aneurysms (AAA).

OBJECTIVE

In this study, we employed multimodal microscopy approaches to characterize how collagen fibril structure impacts platelet adhesion in clinical AAA tissues.

METHODS

Ultrastructural atomic force microscopy (AFM) analysis was performed on tissue sections after staining with fluorescently labeled collagen hybridizing peptide (CHP) to recognize degraded collagen. Second harmonic generation (SHG) microscopy was used on CHP-stained sections to identify regions of intact versus degraded collagen. Finally, platelet adhesion was identified via SHG and indirect immunofluorescence on the same tissue sections.

RESULTS

Our results indicate that ultrastructural features characterizing collagen fibril abnormalities coincide with CHP staining. SHG signal was absent from CHP-positive regions. Additionally, platelet binding was primarily localized to regions with SHG signal. Abnormal collagen fibrils present in AAA (in SHG negative regions) were thus found to inhibit platelet adhesion compared to normal fibrils.

CONCLUSIONS

Our investigations reveal how the collagen fibril structure in the vessel wall can serve as another regulator of platelet-collagen adhesion. These results can be broadly applied to understand the role of collagen fibril structure in regulating thrombosis or bleeding disorders.

Collagen fibril abnormalities in human and mice abdominal aortic aneurysm

Vascular diseases like abdominal aortic aneurysms (AAA) are characterized by a drastic remodeling of the vessel wall, accompanied with changes in the elastin and collagen content. At the macromolecular level, the elastin fibers in AAA have been reported to undergo significant structural alterations. While the undulations (waviness) of the collagen fibers is also reduced in AAA, very little is understood about changes in the collagen fibril at the sub-fiber level in AAA as well as in other vascular pathologies. In this study we investigated structural changes in collagen fibrils in human AAA tissue extracted at the time of vascular surgery and in aorta extracted from angiotensin II (AngII) infused ApoE^-/- mouse model of AAA. Collagen fibril structure was examined using transmission electron microscopy and atomic force microscopy. Images were analyzed to ascertain length and depth of D-periodicity, fibril diameter and fibril curvature. Abnormal collagen fibrils with compromised D-periodic banding were observed in the excised human tissue and in remodeled regions of AAA in AngII infused mice. These abnormal fibrils were characterized by statistically significant reduction in depths of D-periods and an increased curvature of collagen fibrils. These features were more pronounced in human AAA as compared to murine samples. Thoracic aorta from Ang II-infused mice, abdominal aorta from saline-infused mice, and abdominal aorta from non-AAA human controls did not contain abnormal collagen fibrils. The structural alterations in abnormal collagen fibrils appear similar to those reported for collagen fibrils subjected to mechanical overload or chronic inflammation in other tissues. Detection of abnormal collagen could be utilized to better understand the functional properties of the underlying extracellular matrix in vascular as well as other pathologies. STATEMENT OF SIGNIFICANCE: Several vascular diseases including abdominal aortic aneurysm (AAA) are characterized by extensive remodeling in the vessel wall. Although structural alterations in elastin fibers are well characterized in vascular diseases, very little is known about the collagen fibril structure in these diseases. We report here a comprehensive ultrastructural evaluation of the collagen fibrils in AAA, using high-resolution microscopy techniques like transmission electron microscopy (TEM) and atomic force microscopy (AFM). We elucidate how abnormal collagen fibrils with compromised D-periodicity and increased fibril curvature are present in the vascular tissue in both clinical AAA as well as in murine models. We discuss how these abnormal collagen fibrils are likely a consequence of mechanical overload accompanying AAA and could impact the functional properties of the underlying tissue.

Aortocaval fistula, a potentially favourable complication of abdominal aortic aneurysm rupture in endovascular repair

Endovascular aneurysm repair is an established treatment for ruptured abdominal aortic aneurysm. Primary aortocaval fistula is an exceedingly rare finding in ruptured abdominal aortic aneurysm, with a reported incidence of less than 1%. The presence of an aortocaval fistula used to be an unexpected finding in open surgical repair which often resulted in massive haemorrhage and caval injury. We present a case of ruptured abdominal aortic aneurysm with an aortocaval fistula that was successfully treated with percutaneous endovascular aneurysm repair under local anaesthesia. Despite a persistent type 2 endoleak the aneurysm sack shrank from 8.4cm to 4.8cm in 12 months. The presence of an aortocaval fistula may have depressurised the aneurysm, resulting in less bleeding retroperitoneally and may have promoted rapid shrinkage of the sac despite the presence of a persistent type 2 endoleak.

Unusual forms of ruptured abdominal aortic aneurysms

Over 95% of abdominal aortic aneurysms (AAAs) rupture into the retroperitoneal space. Rare types of AAA ruptures comprise ruptures into the inferior vena cava with aortocaval fistula formation (ACF), ruptures into the duodenum with formation of a primary aortoduodenal fistula (ADF), and chronic contained ruptures (CCRs). This article presents a study of 41 cases with unusual forms of ruptured AAA of a series of 506 patients with AAA rupture treated within a 14-year period. There were 11 cases of CCR, 5 cases with ADF, and 25 cases with ACF. The correct preoperative diagnosis was established in 6 (of 11) cases of CCR, in 2 (of 5) cases of primary ADF, and in 13 (of 25) cases of ACF. AAA replacement was performed in 8 cases using a tube graft, whereas a bifurcated graft was used in 31 patients because of the distant extent of the atherosclerotic/aneurysmatic lesions engaging iliac arteries. Two patients had an axillobifemoral bypass. The overall 30-day mortality rate was 19% (8 of 41), with subgroup mortality rates of 0 (CCR), 60% (ADF), and 20% (ACF). Diagnosis and treatment are simplest in cases of CCR and the most complicated in cases of ADF.

Aneurisma ilíaco associado a fístula arteriovenosa

A ruptura dos aneurismas aorto-ilíacos para a veia ilíaca ou veia cava é uma complicação pouco comum. A hipertensão venosa leva a vários sinais e sintomas, o que dificulta o diagnóstico pré-operatório, tais como edema do membro inferior, dispnéia, hematúria, sinais de insuficiência renal ou cardíaca. Sopro abdominal é a chave do diagnóstico clínico, associado à massa pulsátil e dor abdominal. O reconhecimento da fístula arteriovenosa no pré-operatório é importante para o planejamento cirúrgico. Relatamos um caso de aneurisma da artéria ilíaca comum e interna direita associado a fístula para veia ilíaca comum, cursando, inicialmente, com edema do membro inferior direito e dispnéia, o que levou ao diagnóstico incorreto de trombose venosa profunda.

A giant aortocaval fistula due to abdominal aortic aneurysm

Although very rare, the fistula development between vena cava inferior and an abdominal aortic aneurysm is a pathology which can deteriorate the clinical status of the patient rapidly. Today, this pathology can be diagnosed very easily with non-invasive tests, and invasive tests can also be used for diagnostic purposes when needed. Especially spiral computed tomography scan with contrast is usually sufficient to diagnose this pathology. A large-diameter aortocaval fistula case, which to our knowledge never presented in the literature before, and its diagnosis and treatment will be presented in this article.

Spontaneous internal ilio-iliac fistula in an elderly woman presenting as heart failure

Acquired intra-abdominal arteriovenous fistulas (AVFs) are a rare disorder where the communication most commonly occurs between abdominal aorta and inferior vena cava. Ilio-iliac AVF has been reported previously, but is exceedingly rare. We present a case of spontaneous ilio-iliac AVF in an elderly woman who presented with symptoms of right heart failure where the diagnosis was not considered. The computed tomographic (CT) and angiographic features are described. The current status of management as well as a review of the literature is also presented.