Restenosis reducing risk

Due to the pivotal role of platelets in thrombus formation, especially in the arterial system, inhibition of platelet function has become a central pharmacological approach. Antiplatelet drugs are given in order to prevent and treat thromboembolic diseases such as coronary heart disease, peripheral and cerebrovascular disease. They have also revolutionized the procedures of invasive coronary interventions as they reduce the risk of restenosis and thrombosis. 

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. 

The major advantages of the systemic approach to restenosis should be the relatively inexpensive and also powerful and safety method to reduce restenosis in selected group of patients. Oral rapamycin can also be used in determining high risk subsets of patients such as those with diabetes, bifurcations, and in-stent restenotic lesions, alone or in conjunction with DES. In insulin-dependant diabetic patients, oral rapamycin together with DES may help to reduce the still higher than acceptable risk of restenosis that is currently reported with DES. 

Heparin-coated Palmaz-Schatz, Wiktor, Jostent, BX Velocity, and beStent have been investigated in clinical studies. All studies showed that heparin-coated stents are safe, even in high-risk lesions. When compared with balloon angioplasty, heparin-coated stents could significantly reduce the rate of subacute stent thrombosis and the late restenosis. However, no significant difference of restenosis was observed between the heparin-coated stent and the bare stent control. 

Many surgeons routinely use a patch of autologous vein, or synthetic material, to close the artery, enlarge the lumen and so reduce the risk of restenosis and, more importantly, of stroke. Patching increases the surgery time and there are complications, including rupture... 

It happens that NO potently inhibits not only vascular smooth muscle cell proliferation, but also the adhesion, aggregation, and activation of platelets. With this in mind, it will be interesting to see whether the diazeniumdiolated metal stents derivatized as in Figure 7 will both inhibit acute thrombotic failure via NO s antiplatelet activity as well as reduce restenosis risk by way of its cytostatic effect in vascular smooth muscle. 

Stents reduce the acute risk of a coronary intervention and reduce the risk of restenosis afterwards. Today, stent placement is the most frequently performed coronary revascularization treatment. CT represents a possible noninvasive method for the detection of in-stent restenosis, but in the presence of stents imaging, it is impeded by artifacts. Therefore, coronary CT angiography for the evaluation of stents is a controversial topic. Knowledge of the clinical background of the patient, stent type, location of the stent, scanner technology, scan protocols, and image reconstruction methods are crucial to define an indication for the exam and to correctly interpret scan results. 

The BSG guidelines report that approximately 90% of patients treated by dilatation achieve relief of symptoms. Some require repeat dilatation procedures and patients should all be treated with proton pump inhibitors in order to reduce the risk of restenosis. 

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