Stent accessibility

Self-expanding stents with a higher radial force (e.g., WingSpan, Boston Scientific Corp.) will probably play a key role in acute stroke cases related to intracranial atherosclerotic disease. Antegrade flow is essential for the maintenance of vascular patency, as particularly evident in patients with severe proximal stenoses who commonly develop rethrombosis after vessel recanalization. Furthermore, stenting of the proximal vessels may be required in order to gain access to the intracranial thrombus with other mechanical devices or catheters. In a recent series, 23 of 25 patients (92%) with acute n = 15) or subacute n = 10) ICA occlusions were successfully revascularized with this technique. " ... 

Percutaneous coronary intervention A minimally invasive procedure whereby access to the coronary arteries is obtained through the femoral artery up the aorta to the coronary os. Contrast media is used to visualize the coronary artery stenosis using a coronary angiogram. A guidewire is used to cross the stenosis and a small balloon is inflated and/or stent is deployed to break up atherosclerotic plaque and restore coronary artery blood flow. The stent is left in place to prevent acute closure and restenosis of the coronary artery. Newer stents are coated with antiproliferative drugs, such as paclitaxel and sirolimus, which further reduce the risk of restenosis of the coronary artery. 

Cypher Instructions for Use. Cypher sirolimus-eluting coronary stent on Raptor over-the-wire delivery system, http // www.fda.gov/cdrh/PDF2/p020026c.pdf Accessed Aug 8, 2006. 

Treatment of psoriasis with new biologies costs in the range of 25,000- 45,000 per year as compared with 2200 for methotrexate and 3000- 5000 per year for phototherapy. The cost of erythropoietin for renal dialysis is 10,000 per year and for cancer patients 1000 per month of treatment. New vaccines are priced in the 200- 400 range. Xigris is priced at 6800 per injection and drug-coated stents at over 3000. The European government-funded healthcare systems and insurance companies try to delay and limit access to costly new medicines and try to negotiate lower prices. 

FIGURE 15.19 Endoarterial implantation of a BMS, (a) stent + ballon insertion, (b) ballon inflation and stent deposition, and (c) stent position in the coronary wall. (From http //www.medicinenet.com/images. Accessed April, 2012.)... 

Fig. 7.3a,b. Hepatic arteriogram in a 26-year-old man with a small inoperable neuroendocrine tumour in the head of his pancreas. The papilla of Vater could not be accessed at ERCP and he underwent a percutaneous stenting procedure at which two self-expanding stents were inserted (lower arrowheads) apparently side by side (a). 12 hours later repeat ERCP revealed a significant haemorrhage from the papilla. The angiogram revealed a segment 4 arterial pseudoaneurysm (upper arrowheads) which was embolized successfully with coils (b)... 

Careful correlation with prior CT images will help plan the puncture in relation to the markers on the stent graft. Ideally the left side access is used to avoid IVC. However, if necessary the puncture can be done through the IVC. When performed under fluoroscopic guidance it is useful to frequently rotate the X-ray tube from the AP to the lateral projection, and in between, to help in assessing the needle track, and to avoid puncturing the stentgraft. 

Catheters, in their simplest form, are merely tubes inserted into a body cavity for die purpose of fluid removal, injection, or both (Thomas, 1989). The term catheter has been expanded to include a number of tubing-based percutaneous interventional devices used for tasks such as stent delivery and deployment, clot removal, radio-frequency ablation, and intra-aortic balloon cardiac support Because of their prevalence and representative uses, the present section will be limited to vascular infusion catheters and access ports. Stenting and cardiac support applications utilizing catheter-based techniques are discussed elsewhere in this chapter. 

Stent, Oxford University Press. http //www.oxforddictionaries.com/ definition/english/stent search DictCode=aU (accessed 2010)... 

ART Technology (2014) http //www.art-stent.com/technology.php, (accessed 6 October 2014)... 

Nowadays there are several self expanding stents specifically designed for intracranial use available. These stents are extremely flexible and access through tortuous vessels is facilitated. Even distal arteries can be reached easily. Since they are not balloon mounted the risk of damaging the artery is reduced. 

If a peroral route to the stomach outlet or duodenum is not feasible percutaneous gastrostomy using standard techniques (De Baere et al. 1997 Pinto et al. 2001) allows a more direct access. Using a stiff sheath successful catheterisation of the intestinal lumen beyond the obstruction is possible in virtually all cases and also stents mounted on shorter or relatively stiff introducing devices can then be implanted (Pinto 1997 Pinto et al. 2001 Keymling et al. 1993 Truong et al. 1992 Song et al. 1993). 

A combined radiologic-endoscopic technique should be considered to facilitate peroral stent placement if necessary. This interdisciplinary approach further combines the skill and expertise of two highly specialised teams. By using flexible and long enough instruments in combination with an endoscope a percutaneous gastrostomy as a way of access can almost always be avoided. 

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