Aneurysm embolization

Key words endovascular embolization, arteriovenous malformations, aneurysms, embolic materials. 

Figure 7.3 is a schematic showing how stent-assisted embolization can be performed during aneurysm embolization (Lanzino et al, 2005). 

Other types of coils are those that have a controlled release either due to a mechanical release or that of electrochemical dissolution of an attachment joint. These GDC-type coils have the advantage that trial placement is used to accurately size the coil and the ill-sized coil can be removed without danger of distal embolization. The disadvantage is in their high cost which has prevented their widespread use outside of intra-cranial aneurysm embolization. 

Future perspectives Detachable coils can be repositioned until a focal and compact mechanical obstruction is achieved. Detachable coils may be covered with small Dacron strands to promote thrombus formation or with an expanding hydrogel to minimize dead space between the coil loops. Although dedicated detachable coils are available for intracranial aneurysm embolization, the high cost of these coils precludes its routine use in non-neurointerventional indications. 

The direct puncture percutaneous approach to pancreatic aneurysm embolization was first described... 

The SMPU matrix was polyester-based thermoset (Mitsubishi Heavy Industries, Ltd). This SMPU is an amorphous material with two T s at 55°C and 115°C for the switching and hard domains, respectively. The first prototype was a flower-shaped endovascular thrombectomy device, which was intended for stroke treatment. The second prototype device was an expandable SMPU foam device for potential application in aneurysm embolization. Both devices are presented in their collapsed and deployed forms in Fig. 17. Actuation was achieved by inductively heating the... 

Kallmes, D.F., Fujiwara, N.H., 2002. New expandable hydrogel-platinum coil hybrid device for aneurysm embolization. American Joitmal of Neuroradiology 23, 1580-1588. 

For patients undergoing aneurysm embolization, early recognition and management of complications... 

Metcalfe et al. (2003) tested cold hibernated elastic memory (CHEM) polyurethane for the treatment of lateral wall aneurysms on the carotid arteries of dogs. The SMP polyurethane was made in open cellular (foamy) structures with the glass transition temperature of 60 C. After 3 weeks, in vivo experiments showed that the CHEM foam led to improved aneurysm embolization, and a thick neoin-tima formation by favoring the ingrowth of cells. However, residual necks and recurrences were observed in some cases due to the incomplete filling of the vascular lumen. 

CHD = myocardial infarction (Ml), significant myocardial ischemia (angina), history of coronary artery bypass graft (CABG), history of coronary angioplasty, angiographic evidence of lesions, carotid endarterectomy, abdominal aortic aneurysm, peripharal vascular disease (claudication), thrombotic/embolic stroke, transient ischemic attack (TIA)... 

Atherothromboembolism ntracranial small vessel disease Leukoaraiosis Dissection (Table 6.4) Fibromuscular dysplasia Congenital arterial anomalies Moyamoya syndrome Embolism from arterial aneurysms Inflammatory vascular diseases Irradiation... 

Penetrating and non-penetrating neck injuries are more likely to damage the carotid than the better protected vertebral artery. The vertebral artery appears to be more vulnerable to rotational and hyperextension injuries of the neck, particularly at the level of the atlas and axis. Laceration, dissection and intimal tears may be complicated by thrombosis and then embolism and, therefore, ischemic stroke at the time of the injury or some days or even weeks after the injury. Later stroke may be a consequence of the formation of a traumatic aneurysm, arteriovenous fistula or a fistula between the carotid and vertebral arteries (Davis and Zimmerman 1983). 

Carotid loops may be associated with aneurysm formation and rarely with embolism, endothelial damage and thrombosis exceptionally there may be focal ischemia on head movement (Sarkari et al. 1970 Desai and Toole 1975). Rarely, these loops may cause hypoglossal nerve lesions or pulsatile tinnitus. 

Embolism from intra- and extracranial arterial aneurysms... 

Embolism from thrombus within the cavity of an aneurysm is rare and is difficult to prove in cases where there maybe other potential sources of embolization. Intracranial aneurysms more commonly present with rupture and subarachnoid hemorrhage, whereas internal carotid artery aneurysms tend to cause pressure symptoms including a pulsatile and sometimes painful mass in the neck or pharynx, ipsilateral Horner s syndrome or compression of the lower cranial nerves. Extracranial vertebral artery aneurysms may cause pain in the neck and arm, a mass, spinal cord compression and upper limb ischemia (Catala et al. 1993). 

Telangiectasias are collections of dilated capillaries that are usually of no clinical significance (Milandre et al. 1987). They may be associated with hereditary hemorrhagic telangiectasia (the Osler-Weber-Rendu syndrome), but this is more likely to be associated with neurological complications from a pulmonary arteriovenous malformation with right-to-left shunting, such as cerebral hypoxia, brain abscess, paradoxical and septic embolism, or from an associated intracranial arteriovenous malformation or aneurysm (McDonald et al. 1998). 

Once detected, an aneurysm of the hepatic artery requires immediate treatment. Up to a certain size, intrahepatic aneurysms are treated by angiographic embolization. Coagulation by means of direct thrombin injection has also been described. (130) Larger aneurysms are treated by vascular surgery (ligation, vascular reconstruction, resection). (132, 137)... 

It is additionally known that cerebral apoplexy is a result of a sudden circulatory disorder of a human brain area with subsequent functional losses, with corresponding neurological and/or psychological symptoms. The causes of cerebral apoplexy can lie in cerebral haemorrhages (e.g. after a vascular tear in hypertension, arteriosclerosis and apoplectic aneurysms) and ischaemias (e.g. due to a blood pressure drop crisis or embolism). 

Figure 4.54) and dissecting aortic aneurysm (Figure 7.4). An example of ST-segment elevation in massive pulmonary embolism is shown in Figure 4.54, which coincides with the development of... 

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