Angioplasty
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Angioplasty is the mechanical dilation of an artery that have been obstructed, generally due to atheroma (the lesion of atherosclerosis).
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Coronary angioplasty
One way to unblock (open up the lumen) of a coronary artery (or other blood vessel) is angioplasty, or Percutaneous Transluminal Coronary Angioplasty (PTCA). A wire is passed through the diseased coronary artery, to beyond the area of coronary artery that is being worked upon. Over this wire, a balloon catheter is passed into the segment that is to be opened up. The end of the catheter contains a small folded balloon. When the balloon is hydraulically inflated, it compresses the atheromatous plaque and streches the artery wall to expand. At the same time, if an expandable wire mesh tube (stent) was on the balloon, then the stent will be implanted (left behind) to support the new stretched open position of the artery from the inside.
Angioplasty and stenting is performed through a thin flexible catheter during Cardiac Catheterization, often making heart surgery unnecessary. While coronary angioplasty has consistently been shown to reduce symptoms due to coronary artery disease and to reduce cardiac ischemia, it has not been shown in large trials to reduce mortality due to coronary artery disease.
Traditional ("bare metal") coronary stents provide a mechanical framework that holds the artery wall open, preventing stenosis, or narrowing, of arteries feeding critical structures like the myocardium. Traditional stenting is superior to angioplasty alone in keeping arteries open.
Newer stents (called drug-eluting stents) are coated with drugs that prevent re-stenosis of the artery. Two drugs, sirolimus and paclitaxel, have been demonstrated effective and safe in this application by stent device manufacturers and are being used in the US.
Risks of angioplasty include myocardial infarction, cardiac arrhythmia, bleeding and death. These events, fortunately, are uncommon, and the procedure is widely practiced. Coronary angioplasty is usually performed by an interventional cardiologist, a medical doctor with special training in the treatment of the heart using invasive catheter-based procedures.
Angioplasty is often referred to as Dottering, after Dr C.T. Dotter, who, together with Dr M.P. Judkins, first described (http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=14226164&dopt=Abstract) angioplasty (without the balloon) in 1964 (Circulation 1964;30:654-70).
Peripheral angioplasty
Peripheral angioplasty refers to the use of similar techniques in opening blood vessels other than the coronary arteries. It is often called percutaneous transluminal angioplasty or PTA for short. PTA is most commonly done to treat narrowings in the leg arteries, especially the common iliac, external iliac, superficial femoral and popliteal arteries. PTA can also be done to treat narrowings in veins.
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Renal artery angioplasty
Atherosclerotic obstruction of the renal artery can be treated with angioplasty of the renal artery (percutaneous transluminal renal angioplasty, PTRA). Renal artery stenosis can lead to hypertension and loss of renal function.
Carotid angioplasty
Generally, carotid artery stenosis is still not treated with angioplasty and stenting in most hospitals, due to the increased risk of embolic stroke with the procedure. Furthermore, it is not yet FDA approved. However, starting in the early 1990s with new anti-embolic devices designed to reduce or trap atheroma and clot debris, angioplasty and stenting is increasingly being used to also treat carotid stenosis, with success rates similar to carotid endarterectomy surgery. Simple angioplasty without stenting is falling out of favor in this vascular bed. A large trial comparing endarterectomy and stenting found stenting equally efficacious (Yadav et al 2004).
See Also
References
- Yadav JS, Wholey MH, Kuntz RE, Fayad P, Katzen BT, Mishkel GJ, Bajwa TK, Whitlow P, Strickman NE, Jaff MR, Popma JJ, Snead DB, Cutlip DE, Firth BG, Ouriel K. Protected carotid-artery stenting versus endarterectomy in high-risk patients. N Engl J Med 2004;351:1493-501. PMID 15470212.de:PTCA