Coronary arteries balloon dilatation

Laser ablation systems hold considerable promise if restenosis (reblocking of the arteries) rates are reduced. The rate as of 1995 is 30%, typically within six months. Mechanical or atherectomy devices to cut, shave, or pulverize plaque have been tested extensively in coronary arteries. Some of these have also been approved for peripheral use. The future of angioplasty, beyond the tremendous success of conventional balloon catheters, depends on approaches that can reduce restenosis rates. For example, if appHcation of a dmg to the lesion site turns out to be the solution to restenosis, balloon catheters would be used for both dilating the vessel and deUvering the dmg. An understanding of what happens to the arterial walls, at the cellular level, when these walls are subjected to the various types of angioplasty may need to come first. 

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. 

Martinez-Elbal L, Ruiz-Nodar JM, Zueco J, et al. Direct coronary stenting versus stenting with balloon pre-dilation immediate and follow-up results of a multicentre, prospective, randomized study. The DISCO trial. Direct stenting of coronary arteries. Eur Heart J 2002 23 633-640. 

A Swiss physician, Andreas Guentzig, developed the first balloon catheter which was small enough to reach into the coronary arteries. In 1977, he performed the first successful coronary artery dilation treatment. An estimated one million patients per year receive angioplasty as part of their treatment. 

Percutaneous transluminal angioplasty or balloon dilation of the coronary artery results in a dramatic clinical response in many patients. Long-term benefit, however, is dependent on the progression of the disease at the dilated site °. The factors which determine the rate of progression of the disease or the development of acute coronary occlusion are not known but pathological evidence of severe trauma with deposition of platelets and endothelial loss at the angioplasty site suggest that eicosanoids may be important . ... 

Hamek, J., Zoucas, E., de Sa, V.P., Ekblad, E., Amer, A., Stenram, U., 2011. Intimal hyperplasia in balloon dilated coronary arteries is reduced by local dehvery of the NO donor, SIN-1 via a cGMP-dependent pathway. BMC Cardiovascular Disorders 11, 30. 

Acute myocardial infarction can be limited by streptokinase which dissolves fresh clots and opens the artery, but muscle death and necrosis causes a mechanical defect. Subsequent infarcts cause further muscle death and ultimately lead to defective ventricular function and cardiac failure. There is the need for simple alarm systems to detect acute myocardial infarction and less traumatic invasive procedures to dissolve the clot and dilate the artery immediately. Coronary arteries ramify and branch in 3-dimensional space and the present generation of balloon catheters for percutaneous transluminal coronary angioplasty carries a small but definite risk. New, non-traumatic guidewires, low profile dilatation systems and more powerful dilatation balloons which will not rupture the artery are needed. 

Percutaneous translmninal coronary angioplasty (PTCA) is used to widen the stenosis of the coronary without an open surgical procedure. During this procedure, a catheter with a small inflatable balloon on the end is positioned within the narrowed portion of the artery. As the balloon is inflated, the atherosclerotic plaque is compressed and the wall of the artery is stretched, dilating the stenosed segment of the artery This procediue is usually followed by insertion of a stent at the site of stenosis. Figure 12.13 schematically shows the steps of this procedure. 

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