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AngioplastyAngioplasty is the mechanical, hydraulic dilation of a narrowed or totally obstructed arterial lumen, generally caused by atheroma(the lesion of atherosclerosis). Most commonly, the Seldinger techniqueis to cannulate a blood vessel for access. A guiding catheter is introduced into the arterial (or venous) system and advanced through the system to the location of an obstruction. This in turn is followed by introduction of a guidewire which is advanced though the guide catheter, through the obstruction and extended into the blood vessel lumen beyond the obstruction. Over the guidewire, a balloon catheter is advanced through both the guide catheter and the obstruction. Once in position, the balloon in inflated using high hydraulic pressure so as to force the narrowed vessel lumen to expand, pushing the lesion producing the narrowing outwards. The balloon may also include a stent (compressed over the balloon before expansion) or be followed by a stent/balloon combination so that the expanded stent is left within the previously narrowed lumen to mechanically support patency of the vessel lumen.
Coronary angioplastyImage:Ha1.jpg One way to unblock (open up the lumen) of a coronary artery(or other blood vessel) is percutaneous transluminal coronary angioplasty (PTCA). A wire is passed from the femoral arteryin the leg (most commonly) or the radial arteryin the arm up to the diseased coronary artery, to beyond the area of the coronary artery that is being worked upon. Over this wire, a balloon catheteris 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 atheromatousplaqueand 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 catheterduring CardiacCatheterizationwith just a local anaestheticto the groin (or wrist) where the catheterwas inserted, often making heart surgeryunnecessary. 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 with this form of treatment compared with medical therapy, usually consisting of thrombolytic("clot busting") medication. Traditional ("bare metal") coronary stentsprovide 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. 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 fortunately 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 referredto as Dottering, after Dr C.T. Dotter, who, together with Dr M.P. Judkins, first describedangioplasty (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). Risks of angioplastyAngioplasty has become considerably safer over the years and is now commonly performed. Although it is associated with some risks[{{fullurl:Template:FULLPAGENAME}}#endnote_BMJ_risks] these are considerably less than for open-heart bypass surgerywith 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-plateletclotting drugs. Some bruisingis therefore to be expected, but occasionally a haematomamay 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 reactionto 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 strokeof 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. Peripheral angioplastyPeripheral 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. Image:Common iliac PTA 7mm.jpg Renal artery angioplastyAtherosclerotic obstruction of the renal arterycan be treated with angioplasty of the renal artery (percutaneous transluminal renal angioplasty, PTRA). Renal artery stenosis can lead to hypertensionand loss of renal function. Carotid angioplastyGenerally, carotid arterystenosis is still not treated with angioplasty and stenting in most hospitals, due to the increased risk of embolic strokewith 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 atheromaand clot debris, angioplasty and stenting is increasingly being used to also treat carotid stenosis, with success rates similar to carotid endarterectomysurgery. Simple angioplasty without stenting is falling out of favor in this vascular bed. A large trial comparing endarterectomy and stenting found stenting equally efficacious [{{fullurl:Template:FULLPAGENAME}}#endnote_Yadav]. See also
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