Percutaneous coronary intervention

Percutaneous coronary intervention (PCI) is a non-surgical procedure used to treat narrowing (stenosis) of the coronary arteries of the heart found in coronary artery disease. After accessing the blood stream through the femoral or radial artery, the procedure uses coronary catheterization to visualise the blood vessels on X-ray imaging. After this, an interventional cardiologist can perform a coronary angioplasty, using a balloon catheter in which a deflated balloon is advanced into the obstructed artery and inflated to relieve the narrowing; certain devices such as stents can be deployed to keep the blood vessel open. Various other procedures can also be performed.

PCI is used primarily to open a blocked coronary artery and restore arterial blood flow to heart tissue, without requiring open-heart surgery. In patients with a restricted or blocked coronary artery, PCI may be the best option to re-establish blood flow as well as prevent angina (chest pain), myocardial infarctions (heart attacks) and death. Today, PCI usually includes the insertion of stents, such as bare-metal stents, drug-eluting stents, and fully resorbable vascular scaffolds (or naturally dissolving stents). The use of stents has been shown to be important during the first three months after PCI; after that the artery can remain open on its own. This is the premise for developing bioresorbable stents that naturally dissolve after they are no longer needed.

The patient is usually awake during angioplasty, and chest discomfort may be experienced during the procedure. The patient remains awake in order to monitor the patient's symptoms. If symptoms indicate the procedure is causing ischemia the cardiologist may alter or abort part of the procedure. Bleeding from the insertion point in the groin (femoral artery) or wrist (radial artery) is common, in part due to the use of antiplatelet 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.

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.

Newer drug-eluting stents (DES) are traditional stents with a polymer coating containing drugs that prevent cell proliferation. The antiproliferative drugs are released slowly over time to help prevent tissue growth — which may come in response to the stent — that can block the artery. These types of stents have been shown to help prevent restenosis of the artery through physiological mechanisms that rely upon the suppression of tissue growth at the stent site and local modulation of the body’s inflammatory and immune responses. The first two drug-eluting stents to be utilized were the paclitaxel-eluting stent and the sirolimus-eluting stent, both of which have received approval from the U.S. Food and Drug Administration. Most current FDA-approved drug-eluting stents use sirolimus (also known as rapamycin), everolimus and zotarolimus. Biolimus A9-eluting stents, which utilize biodegradable polymers, are approved outside the U.S.

Newer-generation PCI technologies aim to reduce the risk of late stent thrombosis or other long-term adverse events. Some DES products market a biodegradable polymer coating with the belief that the permanent polymer coatings of DES contribute to long-term inflammation. Other strategies: A more recent study proposes that, in the case of population with diabetes mellitus—a population particularly at risk—a treatment with paclitaxel-eluting balloon followed by BMS may reduce the incidence of coronary restenosis or myocardial infarction compared with BMS administered alone.

Current concepts recognize that after three months the artery has adapted and healed and no longer needs the stent. Complete revasculariztion of all stenosed coronary arteries after a STEMI is more efficacious in terms of major adverse cardiac events and all-cause mortality, while being safer than culprit-vessel-only approach.

In 2007 the New England Journal of Medicine published the results of a trial called COURAGE. The study compared stenting as used in PCI to medical therapy alone in symptomatic stable coronary artery disease (CAD). This showed there was no mortality advantage to stenting in stable CAD, though there was earlier relief of symptoms which equalized by five years. After this trial there were widely publicized reports of individual doctors performing PCI in patients who did not meet any traditional criteria. A 2014 meta-analysis showed there may be improved mortality with second generation drug-eluting stents, which were not available during the COURAGE trial. Medical societies have since issued guidelines as to when it is appropriate to perform percutaneous coronary intervention. In response the rate of inappropriate stenting was seen to have declined between 2009 and 2014. Statistics published related to the trends in U.S. hospital procedures, showed a 28% decrease in the overall number of PCIs performed in the period from 2001 to 2011, with the largest decrease notable from 2007. One study found that symptom relief in people with stable angina after percutaneous coronary intervention is similar to placebo.