Angioplasty
From Wikipedia, the free encyclopedia
Angioplasty is the mechanical widening of a narrowed or totally obstructed blood vessel. These obstructions are often caused by atherosclerosis. The term derives from the roots "angio" or vessel and "plasticos" fit for molding. The term has come to include all manner of vascular interventions typically performed in a minimally invasive or percutaneous method.
Contents |
[edit] Coronary angioplasty
One way to unblock a coronary artery is percutaneous transluminal coronary angioplasty (PTCA), which was first performed in 1977 by Andreas Gruentzig. A wire is passed from the femoral artery in the leg (or, less commonly, from the radial artery or brachial artery in the arm) to beyond the area of the 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 stretches 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 with just a local anaesthetic to the groin (or wrist) where the catheter was inserted, 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, except in patients being treated for a heart attack acutely (also called primary angioplasty). There is a small but definite mortality benefit (ie., reduction) with this form of treatment compared with medical therapy, usually consisting of thrombolytic ("clot busting") medication.
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 drug-eluting stents (DES) are coated with drugs that prevent re-stenosis of the artery. Three drugs, sirolimus, everolimus and paclitaxel, have been demonstrated effective and safe in this application by stent device manufacturers and are being used.
Risks of angioplasty 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 sometimes referred to as Dottering, after Dr C.T. Dotter, who, together with Dr M.P. Judkins, first described angioplasty (without the balloon) in 1964 (Circulation 1964;30:654-70). As the range of procedures performed upon lumens of coronary arteries has widened, the name of the procedure has changed to percutaneous coronary intervention (PCI).
[edit] Risks of angioplasty
Angioplasty has become considerably safer over the years and is now commonly performed. Although it is associated with some risks[1] these are considerably less than for open-heart bypass surgery with its resulting post-operative pain. However the likelihood of recurrence of angina, and requirement for repeated procedures has been higher with angioplasty. The latest trial (ARTS II) has suggested that PCI with DES may be superior, at least in the short term.
Some chest discomfort occasionally may be experienced and it is for this reason that the patient is awake during minimally invasive angioplasty; the reporting of any symptom allows the cardiologist to take necessary immediate action. 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 haematoma may form. This may delay hospital discharge as flow from the artery into the haematoma may continue (pseudoaneurysm) which requires 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.
In the long term, the most common risk is of the stent restenosis, as discussed above. This has been reduced considerably with the use of newer stents coated with certain medicines (drug-eluting stents). The most serious risk is the rare provocation (3%) of a heart attack during or shortly after the procedure; this may require emergency open cardiac 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.
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 than this.
When failures of PTCA occur, they are often treated using coronary artery bypass grafting (CABG).
[edit] 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.
[edit] 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.
[edit] Carotid angioplasty
Generally, carotid artery stenosis is treated with angioplasty and stenting for high risk patients in many hospitals. It has changed since the FDA has approved the first cartoid stent system (Cordis) in July 2004 and the second (Guidant) in August 2004. The system comprises a stent along with an embolic capture device designed to reduce or trap emboli 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. SAPPHIRE, a large trial comparing carotid endarterectomy and carotid stenting with the Cordis stent found stenting non-inferior to carotid endarterectomy. [2].
[edit] See also
[edit] References
- ^ UK's NHS endorsed 'Best Treatments' advice on 'clinical evidence for patients from the BMJ' on Coronary angioplasty and its risks
- ^ 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.
