Stent technique

Percutaneous coronary intervention (PCI) is one of a host of techniques performed by using a catheter inserted via a major limb artery that aims to relieve nanowing of coronary arteries. For example, percutaneous transluminal coronary angioplasty (PTCA) is the classic PCI that uses a catheter-directed balloon to dilate a stenotic coronary artery, and more recent PCIs include stent implantation, rotational atherectomy, and laser angioplasty. 

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. " ... 

Modern Angioplasty and Stent Technology Technique, Application and Efficacy, Comparison to Surgical... 

PCI was performed using standard techniques (6,30). All 100 patients received one or more identical close cell-stent design. The same stent design was used in order to avoid potential bias with stent selection in both groups. All patients received 325 mg/day of aspirin indefinitely and clopidogrel as a loading dose of 300 mg on the day of the procedure and 75 mg/day thereafter for one month. Statins were given to all patients indefinitely. 

In addition, attempts to deliver radiation therapy to symptomatic de novo or restenotic native coronary-artery lesions included the deployment of very low activity 32P radioactive stents. Preliminary data for clinical endpoints (e.g., subacute stent thrombosis, TLR, and death at 30 days) appeared promising, but the long-term angiographic follow-up revealed an unacceptable restenosis rate at or beyond the stent edges (21,22). Consequently, further studies to evaluate this technique were abandoned. 

The stent struts are comprised of the metal and the polymer, and, overtime, the drug disappears (e.g., with the Cypher stent) or some drug will remain (e.g., with the Taxus stent). Thus, there is the potential for some metal, polymer, and drug to remain exposed to the blood stream. Using high-resolution imaging techniques, intimal hyperplasia is seen when looking at BMS in vivo. 

With the ongoing refinement of endovascular devices and techniques for carotid revascularization, catheter-based therapy has become technically feasible in most patients. Notwithstanding, appropriate case selection is required to ensure procedural safety, Here within we review new concepts pertaining to patient selection and technical procedural considerations that we consider crucial for enhancing clinical outcomes following carotid stenting,... 

Due to the very low event rates in patients with asymptomatic lesions of moderate severity (<60% diameter stenosis), it is unknown whether currently available interventional techniques can improve long-term outcomes over those achievable with optimal medical management. Also unresolved are the indications for carotid stenting in asymptomatic individuals with contralateral carotid occlusion (53) and those undergoing major cardiac or vascular surgery (54). 

Removal of balloon-occlusive EPDs is preceded by aspiration of 50-60 ml of blood using a dedicated catheter. Filter-based EPDs are removed using a dedicated retrieval catheter. Difficulties in advancing the retrieval catheter through the stent are at time eliminated by having the patient rotate his/her neck. Rarely, the filter can become obstructed by large amounts of embolic material and blood flow in the ICA is interrupted. Facile technique and optimal antiplatelet therapy prevent this complication in most cases. 

Patients who continue to bleed despite the above measures require surgery (ligation or transection of varices) or placement of a stent between intrahepatic branches of the portal and (systemic) hepatic veins under radiological control. The latter is now the technique of choice for the 10-15% of patients with acute bleeding resistant to conventional treatment, and also for long-term management of patients who are difficult to help by other methods (see below). 

Therapy Asymptomatic patients do not need any treatment. With symptomatic patients, it is important to use therapeutic strategies which are directed towards the predominant symptoms. These include removal of gallstones by means of sphincterotomy (beware of varices ), antibiotics, placement of a stent, cholagogue agents, TIPS and surgical techniques. (21, 36, 63,106,157)... 

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