Percutaneous coronary intervention
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/* Coronary stenting */ Quantified "rare" as per the NEJM reference. The escardio.org reference for this sentence is broken.
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[[Image:Ha1.jpg|thumb|300px|A [[coronary angiogram]] (an X-ray with radio-opaque contrast in the coronary arteries) that shows the left [[coronary circulation]]. The distal [[left main coronary artery]] (LMCA) is in the left upper quadrant of the image. Its main branches (also visible) are the [[left circumflex artery]] (LCX), which courses top-to-bottom initially and then toward the centre/bottom, and the [[left anterior descending]] (LAD) artery, which courses from left-to-right on the image and then courses down the middle of the image to project underneath of the distal LCX. The LAD, as is usual, has two large diagonal branches, which arise at the centre-top of the image and course toward the centre/right of the image.]]
'''Percutaneous coronary intervention''' ('''PCI'''), commonly known as '''coronary angioplasty''' or simply '''angioplasty''', is a therapeutic procedure to treat the [[stenosis|stenotic]] (narrowed) [[coronary artery|coronary arteries]] of the [[heart]] found in [[coronary heart disease]]. These stenotic segments are due to the build up of [[cholesterol]]-laden plaques that form due to [[atherosclerosis]]. PCI is usually performed by an [[interventional cardiology|interventional cardiologist]].
==History==
{{main|History of invasive and interventional cardiology}}
Coronary angioplasty, also known as "[[percutaneous]] transluminal coronary angioplasty" (PTCA), was first developed in 1977 by [[Andreas Gruentzig]]. The procedure was quickly adopted by numerous [[cardiologist]]s, and by the mid-1980s, many leading medical centers throughout the world were adopting the procedure as a treatment for [[coronary heart disease|coronary artery disease]] (CAD).
Angioplasty is sometimes [[eponym]]ously referred to as ''Dottering'', after Dr [[Charles Theodore Dotter]], who, together with Dr Melvin P. Judkins, first described angioplasty in 1964.<ref>Dotter, C. T. and M. P. Judkins, [http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=14226164&dopt=Abstract ''Transluminal Treatment of Arteriosclerotic Obstruction: Description of a New Technic and a Preliminary Report of Its Application''], Circulation, 1964; [http://www.circ.ahajournals.org/cgi/reprint/30/5/654 30:654-70].</ref> As the range of procedures performed upon coronary artery [[Lumen (anatomy)|lumens]] has widened, the name of the procedure has changed to [[percutaneous coronary intervention]] (PCI).
==Indications==
Percutaneous coronary intervention can be performed to reduce or eliminate the symptoms of coronary artery disease, including [[angina pectoris|angina]] (chest pain), dyspnea (shortness of breath) on exertion, and [[heart failure|congestive heart failure]]. PCI is also used to abort an acute [[myocardial infarction]], and in some specific cases it may reduce [[death|mortality]].
Angioplasty is less invasive than [[coronary artery bypass surgery]] (CABG) and is not inferior to CABG in single-vessel coronary disease.{{Fact|date=January 2008}} However, CABG is superior to PCI in multivessel CAD (two or more diseased arteries) in terms of death, [[myocardial infarction]] and repeat revascularization - regardless of type of stent (bare metal<ref name="SoS 2002">{{cite journal |author=SoS Investigators |title=Coronary artery bypass surgery versus percutaneous coronary intervention with stent implantation in patients with multivessel coronary artery disease (the Stent or Surgery trial): a randomised controlled trial |journal=Lancet |volume=360 |issue=9338 |pages=965–70 |year=2002 |pmid=12383664 |doi=}}</ref> or drug-eluting<ref name="Hannan 2008">{{cite journal |author=Hannan EL, Wu C, Walford G, ''et al'' |title=Drug-eluting stents vs. coronary-artery bypass grafting in multivessel coronary disease |journal=N. Engl. J. Med. |volume=358 |issue=4 |pages=331–41 |year=2008 |pmid=18216353 |doi=10.1056/NEJMoa071804}}</ref>).
==Procedures==
The term [[balloon angioplasty]] is commonly used to describe percutaneous coronary intervention, which describes the inflation of a balloon within the coronary artery to crush the plaque into the walls of the artery. While balloon angioplasty is still done as a part of nearly all percutaneous coronary interventions, it is rarely the only procedure performed.
Other procedures that are done during a percutaneous coronary intervention include:
* Implantation of [[stent]]s
* Rotational or laser [[atherectomy]]
* [[Brachytherapy]]
Sometimes a small mesh tube, or "[[stent]]", is introduced into the blood vessel or artery to prop it open using percutaneous methods. Angioplasty with [[stent]]ing is a viable alternative to [[coronary artery bypass surgery|heart surgery]] for some forms of non-severe coronary artery disease.<ref>Michaels, A. D. and K. Chatterjee, [http://circ.ahajournals.org/cgi/content/full/106/23/e187 ''Angioplasty Versus Bypass Surgery for Coronary Artery Disease''], Circulation, 2002; 106:e187</ref> It has consistently been shown to reduce symptoms due to [[coronary artery disease]] and to reduce cardiac [[ischemia]], but has not been shown in large trials to reduce mortality due to coronary artery disease, except in patients being treated for a heart attack acutely (also called primary angioplasty). There is a small but definite reduction of [[death|mortality]] with this form of treatment compared with medical therapy, which usually consists of the administration of [[thrombolysis|thrombolytic]] ("clot busting") medication.<ref>Mercado, N, Flather, MD, Boersna, E, et al, on Behalf of the Trial Investigators [http://www.medscape.com/viewarticle/460976 CABG vs Stenting for Multivessel Disease: a Meta-analysis of ARTS-1, SoS, ERACI-2, and MASS-2], Presentation at European Society of Cardiology Congress 2003</ref><ref>W. D. Weaver, R. J. Simes, A. Betriu, C. L. Grines, F. Zijlstra, E. Garcia, L. Grinfeld, R. J. Gibbons, E. E. Ribeiro, M. A. DeWood and F. Ribichini [http://jama.highwire.org/cgi/content/abstract/278/23/2093 ''Comparison of primary coronary angioplasty and intravenous thrombolytic therapy for acute myocardial infarction: a quantitative review''], Journal of the American Medical Association 278:23, December 17, 1997.</ref>
===Technique===
The angioplasty procedure usually consists of most of the following steps and is performed by physicians, [[physician assistants]], [[nurse]]s, [[radiologist|radiological technologists]] and cardiac invasive specialist; all whom have extensive and specialized training in these types of procedures.
#Access into the [[femoral artery]] in the leg (or, less commonly, into the [[radial artery]] or [[brachial artery]] in the arm) is created by a device called an "introducer needle". This procedure is often termed [[percutaneous]] access.
#Once access into the artery is gained, a "sheath introducer" is placed in the opening to keep the artery open and control bleeding.
#Through this sheath, a long, flexible, soft plastic tube called a "guiding catheter" is pushed. The tip of the guiding catheter is placed at the mouth of the coronary artery. The guiding catheter also allows for radiopaque dyes (usually iodine based) to be injected into the coronary artery, so that the disease state and location can be readily assessed using real time x-ray visualization.
#During the x-ray visualization, the cardiologist estimates the size of the coronary artery and selects the type of balloon catheter and coronary guidewire that will be used during the case. [[Heparin]] (a "blood thinner" or medicine used to prevent the formation of clots) is given to maintain blood flow.
#The coronary guidewire which is an extremely thin wire with a radio-opaque flexible tip that is inserted into through the guiding catheter and into the coronary artery. While visualizing again by real-time x-ray imaging, the cardiologist guides the wire through the coronary artery to the site of the stenosis or blockage. The tip of the wire is then passed across the blockage. The cardiologist controls the movement and direction of the guide wire by gently manipulating the end that sits outside the patient through twisting of the guidewire.
#While the guidewire is in place, it now acts as the pathway to the stenosis. The tip of the angioplasty or balloon catheter is hollow and is then inserted at the back of the guidewire--thus the guidewire is now inside of the angioplasty catheter. The angioplasty catheter is gently pushed forward, until the deflated balloon is inside of the blockage.
#The balloon is then inflated, and it compresses the [[atheromatous plaque]] and stretches the artery wall to expand.
#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.<ref>[http://www.heartsite.com/html/ptca.html PTCA or Balloon Angioplasty]</ref>
===Coronary stenting===
Traditional ("bare metal") [[coronary stent]]s provide a mechanical framework that holds the artery wall open, preventing stenosis, or narrowing, of coronary arteries. PTCA with stenting has been shown to be superior to angioplasty alone in patient outcome by keeping arteries patent for a longer period of time.<ref>MM Gandhi, and KD Dawkins [http://www.bmj.com/cgi/content/full/318/7184/650/DC1 Clinical review: Intracoronary stents] BMJ 1999;318(7184):650 (6 March)</ref>
Newer [[drug-eluting stent]]s (DES) are traditional stents that are coated with drugs, which, when placed in the artery, release certain drugs over time. It has been shown that these types of stents help prevent restenosis of the artery through several different physiological mechanisms, which rely upon the suppression of tissue growth at the stent site and local modulation of the body's inflammatory and immune responses. Four drugs, Zotarolimus, [[sirolimus]], [[everolimus]] and [[paclitaxel]], have been demonstrated safety and efficacy in this application in controlled clinical trials by stent device manufacturers. {{Fact|date=March 2007}} However, in [[2006]] three broad European trials seem to indicate that drug-eluting stents may be susceptible to an event known as "late stent thrombosis", where the blood-clotting inside the stent can occur one or more years post-stent. Late stent thrombosis occurs in 0.9% of patients, and is extremely dangerous and is fatal in about one-third of cases when the thrombosis occurs.<ref>L Mauri, W Hsieh, JM Massaro, KKL Ho, R D’Agostino, and DE Cutlip. [http://content.nejm.org/cgi/reprint/NEJMoa067731.pdf Stent Thrombosis in Randomized Clinical Trials of Drug-Eluting Stents] N Engl J Med 2007;356:1020-9.</ref><ref>European Society of Cardiology Science News, 2007 [http://www.escardio.org/vpo/News/Scientific/wcc-thrombosis-drug-eluting-stents.htm Thrombosis is the price for the success of drug-eluting stents]</ref>
==Risks==
Coronary angioplasty is widely practiced and has a number of risks,<ref>[[United Kingdom|UK]]'s [[NHS]] endorsed 'Best Treatments' advice on '[[Evidence-based medicine|clinical evidence]] for patients from the [[BMJ]]' on [http://www.besttreatments.co.uk/btuk/electsurgery/18627.html Coronary angioplasty] and its [http://www.besttreatments.co.uk/btuk/electsurgery/18627.html#What%20are%20the%20risks%20of%20coronary%20angioplasty? risks]</ref> however major procedural complications are uncommon. 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. {{Fact|date=March 2007}}
The patient is usually awake during angioplasty, and chest discomfort may be experienced during the procedure; the reporting of symptoms indicates the procedure is causing [[ischemia]] and the cardiologist may alter or abort part of the procedure. Bleeding from the insertion point in the groin is common, in part due to the use of anti-[[platelet]] clotting drugs. Some [[bruising]] is therefore to be expected, but occasionally a [[hematoma]] may form. This may delay hospital discharge as flow from the artery into the hematoma may continue (pseudoaneurysm) which requires surgical repair. Infection at the skin puncture site is rare and [[dissection]] (tearing) of the access blood vessel is uncommon. [[Allergic reaction]] to the contrast dye used is possible, but has been reduced with the newer agents. Deterioration of kidney function can occur in patients with pre-existing kidney disease, but kidney failure requiring dialysis is rare. Vascular access complications are less common and less serious when the procedure is performed via the radial artery.{{Fact|date=January 2008}}
The most serious risks are death, [[stroke]], [[myocardial infarction]] (heart attack) and [[aortic dissection]]. A heart attack during or shortly after the procedure occurs in 3% of cases; this may require emergency [[coronary artery bypass surgery]]. Angioplasty carried out shortly after a [[myocardial infarction]] has a risk of causing a [[stroke]] of 1 in 1000, which is less than the 1 in 100 risk encountered by those receiving thrombolytic drug therapy.{{Fact|date=January 2008}}
The overall risks of death with angioplasty is approximately 1%, but the underlying severity of the heart disease, fitness of the patient and presence of other illness affect each individual’s risk. Hence for those with relatively minor heart disease, preserved good cardiac function, reasonable level of fitness and absence of other illnesses, the risk will be considerably less.{{Fact|date=January 2008}} When failures of PTCA occur, they are treated with medical management or [[coronary artery bypass surgery]] (CABG).
==See also==
* [[Angioplasty]]
* [[Cardiac catheterization]]
* [[Coronary artery bypass surgery]]
* [[Cutting balloon]]
* [[Door-to-balloon]]
==References==
{{reflist}}
==External links==
* [http://www.angioplasty.org Angioplasty.Org], celebrating a decade of independent cardiology news and education
* [http://www.escardio.org/eapci European Association]of Percutaneous Cardiovascular Interventions (EAPCI)
[[Category:Cardiology]]
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