Aneurysms pseudoaneurysm

Fifteen years ago, the only option for patients with large abdominal aortic aneurysms (AAA) that required either elective or emergent repair was an open surgical approach using a transperitoneal or retroperitoneal incision. Now with the advent of endovascular approaches to aortic diseases, many patients, especially those in the high-risk groups, have a minimally invasive option to permit repair of aortic aneurysms, dissections, pseudoaneurysms, and ruptures. 

Congenital anomalies and aneurysms in the hepatic arteries are very rare. (129) Acquired aneurysms are the result of vessel wall damage, injuries or inflammatory processes. (I3l, 133, 136) Pseudoaneurysms may occur after acute pancreatitis and the formation of pseudocysts. (135) (s. tab. 39.5)... 

A 71-year-old man with bladder carcinoma in situ received six instillations of BCG at weekly intervals followed 3 months later by three booster instillations at weekly intervals. Four months later an inflammatory aortic aneurysm, which had ruptured into a pseudoaneurysm, was diagnosed and excised. Mycobacterium bovis was found. After treatment with isoniazid and rifampicin he recovered. There was no sign of tumor in the bladder at cystocopy 8 months after the last BCG instillation. 

Phatouros CC, Sasaki TY, Higashida RT,et al. (2000) Stent-supported coil embolization the treatment of fusiform and wide-neck aneurysms and pseudoaneurysms. Neurosurgery 47 107-113... 

Any aneurysm detected on the arterial tributaries located in the bleeding area should be considered as a pseudoaneurysm and therefore treated as a contrast medium extravasation. 

Ultrasound is useful for many aspects of pancreatitis but has a sensitivity of less than 73% for visceral pseudoaneurysm in the condition, vdiereas contrast enhanced computer tomography (CECT) has a sensitivity of almost 100% [22]. CECT is also very useful in terms of endovascular treatment as it can indicate what type of aneurysm has formed, which artery it has formed from and whether there is more than one. 

Aneurysms and pseudoaneurysms causing haemobilia or associated with pancreatitis are potentially fatal. Imaging, particularly CECT, is vital to their diagnosis. Conservative therapy is a poor option and treatment, which was formally via open surgery, is now best carried out by angiography and percutaneous coil embolization in haemobilia and for Type la and b pancreatitis associated pseudoaneurysms. Percutaneous CT guided thrombin therapy is indicated for Type 2 aneurysms. 

Capek P, Rocco M, McGahan J et al (1992) Direct aneurysm puncture and coil occlusion a new approach to pari-pancreatic arterial pseudoaneurysms. JVIR 3 653-656... 

AAAs present in three different types or shapes. Fusiform aneurysms, the most typical, are mostly symmetrical bulges that occur around the entire circumference of the aorta. These are sometimes referred to as false aneurysms or pseudoaneurysms, because layers of the wall of the aorta are missing (as opposed to the presence of all three layers in a true aneurysm). An aortic dissection, on the other hand, is when blood penetrates the inner layer of the aortic wall, and flows between the layers, similar to delamination. This typically occurs in the thoracic region of the aorta, but can sometimes occur in the abdominal region. Figure 21.3 shows these various types of aneurysms. 

As outlined by Houdart et al. (1993), the depiction of intranidal aneurysms is difficult it is often performed at the time of superselective angiography. Moreover, true arterial intranidal aneurysms have to be distinguished from pseudoaneurysms, which are at the point of rupture of the nidus or of the venous drainage. 

A wedge position of the tip of the catheter may produce rebleeding as well, because the injection force is directly transmitted to the pseudoaneurysm (Lasjaunias et al. 1988). Glue embolization is performed as usual, with the aim of occluding the nidus and aneurysm at the same shot. 

Classification of intracranial aneurysms may be based on morphology, size, location and etiology. The majority of intracranial aneurysms are true aneurysms containing all layers or components of the normal vessel wall. In contrast, in false aneurysms or pseudoaneurysms, the vascular lumen does not enlarge, although the external diameter of the abnormal segment may be increased. These aneurysms are rare within the skull. 

Fig. 5. 2a-f. Dissection of the right internal carotid artery with extracranial enlarging pseudoaneurysm. a Contrast-enhanced MR angiography demonstrating the aneurysm at the extracranial ICA. b Conventional DSA, oblique view, c CT angiography, sagittal reformation reveals the small aneurysm neck, d Conventional DSA before and (e,f) after endovascular coil embolization demonstrating aneurysm occlusion with preservation of the internal carotid artery... 

Accompanying IMHs can be detected in nonenhanced scans and verify the penetrating character of the lesion. Furthermore, nonenhanced scans facihtate the therapeutically relevant differentiation between pseudoaneurysms as a comphcation of a PAU and a sacciform aortic aneurysm. Mural calcifications suggest an aneurysm. In the case of a spacious IMH or paraaortic hematoma, the differentiation between a ruptured aneurysm and a complicated PAU can be impossible. However, in both cases, an immediate therapeutic intervention is indicated. Complications of a PAU, hke AD, formation of a pseudoaneurysm, or aortic rupture can all be detected or excluded in the same scan. 

The arterial wall is composed of three layers. The outer serosal covering is the adventitia, the muscular middle layer is the media, and the inner lining is the intima. True aneurysms are distinguished from false or pseudoaneurysms based on which layers of the arterial wall are present in the aneurysm itself. In order to classify an aneurysm as being true, it must be comprised of all three layers. Pseudoaneurysms have any combination less than all three of the arterial wall components. 

Other causes of saccular aneurysm formation include trauma and iatrogenic injury from percutaneous or surgical interventions. Any focal insult, perforation, or laceration can lead to pseudoaneurysm formation. These aneurysms are often symptomatic due to hemorrhage, pain, and hypotension that occur. Iatrogenic injuries will be discussed in a separate chapter of this text. 

Fig. 8.3. a Celiac angiogram in a patient with portal hypertension demonstrating a distal splenic artery aneurysm, b Celiac angiogram from another patient with multiple splenic aneurysms associated with portal hypertension who has undergone liver transplantation. Note the large hepatic pseudoaneurysm just medial to the upper pole of the right kidney, c Selective common hepatic artery injection in the patient from b... 

Generally, SMA aneurysms are mycotic, celiac aneurysms develop from cystic medial degeneration, GDA pseudoaneurysms occur in the presence of duodenal ulceration, and gastroepiploic and pancreaticoduodenal aneurysms arise secondary to inflammatory changes from pancreatitis. Other causes include polyarteritis nodosa, amphetamine abuse, and connective tissue disorders. 

As long as there is no celiac, proper hepatic, or SMA origin occlusion, the GDA can be sacrificed. If the GDA is required to maintain perfusion of the liver or, if flow into the SMA is dependent upon the celiac, then direct coiling of GDA pseudoaneurysms is preferable. This can he accomplished with stent placement over the aneurysm neck and microcoil deposition through the interstices via a microcatheter. A small-caliher stent graft such as a Jostent could theoretically be used in this situation. However, use of this device is still not approved by the FDA. Appel et al. described the placement of a 26-mm stent graft for humanitarian treatment of a traumatic pseudoaneurysm of the SMA [34]. 

Typically pseudoaneurysm formation in the renal artery distribution is iatrogenic or traumatic. Other causes of aneurysm formation include fihromuscu-lar dysplasia, polyarteritis nodosa, amphetamine abuse, angiomyolipoma in the presence or absence of tuberous sclerosis, and neurofibromatosis. 

Salam TA et al. (1992) Nonoperative management of visceral aneurysms and pseudoaneurysms. Am J Surg 164 215-219... 

We have successfully utilized a few different techniques of stent-reconstruction for the management of CBS, which can be broadly classified as follows. First, in a similar fashion to techniques developed for the treatment of wide-neck aneurysms of the intracranial circulation [37,53-56], endovascular stenting across a pseudoaneurysm can be per-... 

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