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Percutaneous Coronary Intervention
Catheter treatment of narrowings and blockages in the coronary arteries
Percutaneous coronary intervention (PCI), also known as coronary angioplasty, is a catheter-based procedure used to treat the narrowed coronary arteries in patients with ischaemic heart disease. PCI is performed by an interventional cardiologist, a specially trained heart specialist, usually following a diagnostic coronary angiography. During PCI, a cardiologist places a tiny deflated cylinder-shaped balloon at the tip of a catheter under the X-ray control to the site of blockage in the coronary artery. The balloon is then inflated to crush the plaque into the walls of the artery. The procedure usually involves implantation of stents (metallic mesh) to the site of original narrowing or blockage to prop it open. Traditional ("bare-metal stents", BMS) have been largely superseded by drug-eluting stents (DES) which release drugs to prevent restenosis of the coronary artery. Bioresorbable stents (BRS) are so far the newest devices, which aim to provide the mechanical support to the vessel in the acute stage and then disappear avoiding the long-terms problems with implanted foreign material.
ST segment elevation myocardial infarction (STEMI) •Primary PCI is the method of choice for treatment of STEMI patients. Multiple clinical trials have consistently shown that angioplasty is prognostically beneficial in people with acute coronary syndromes; primary angioplasty in acute heart attack opens blocked coronary arteries far quicker and more reliably than thrombolytic (‘clot-busting’) medication.
•Rescue PCI in patiens with failed thrombolysis (clot-busting medication).
•Early intervention in patients treated at the acute stage with thrombolysis.
Non-ST elevation acute coronary syndrome (NST ACS) - unstable angina and non-ST elevation myocardial infarction (NSTEMI) •Early invasive investigation (coronary angiography) followed by PCI reduces in moderate to high risk patients subsequent myocardial infarction and refractory angina.
Stable coronary artery disease •Persistent severe symptoms despite optimal medication. However, there is no evidence that angioplasty improves prognosis in people with stable angina.
•Certain anatomical patterns of coronary artery disease (significant left main artery stenosis and left anterior descending artery disease, especially in the presence of multivessel disease).
Alternative methods of revascularization
An alternative to PCI is coronary artery bypass grafting (CABG), which bypasses stenotic arteries using arteries (most commonly LIMA, left internal mammary artery) and veins (usually harvested from legs). The choice of revascularization between PCI and CABG depends on many factors, including number, complexity, location and functional impact of coronary artery lesions, presence of diabetes mellitus and age. Syntax score based on angiographic classifications of coronary lesions allows prospective calculation of the risk of major adverse cardiac events (MACE), i.e. cardiac death, nonfatal myocardial infarction, or target lesion revascularization. Studies showed that patients with low Syntax score (less advanced disease) did prognostically well with both PCI and CABG but patients with high Syntax score (more advanced disease) were better off with CABG. Often, in absence of prognostic difference, coronary revascularization with PCI is considered as less invasive, with lower risk of stroke but more often needs to be repeated in the future whereas CABG is a bigger initial undertaking but usually with less need for repeated procedures.
Considerations and contraindications
•Situations where optimal medical therapy or CABG is considered superior to PCI.
•Contraindications to antiplatelet drugs (these drugs are critically important to prevent thrombosis, blod clotting in the stent and must be normally taken for 12 months following the procedure).
•Lack of patient adherence to the antiplatelet medication.
•Likelihood of impeding surgery with increased risk of bleeding if performed on antiplatelet drugs or with risk of coronary thrombosis if these drugs are stopped.
Risks and complications
Coronary angioplasty is a safe and routine procedure with risk of major complications less than 1% in elective patients. The common mild problems are transitory chest discomfort during the procedure because the balloon briefly blocks off the blood supply to the heart muscle and some bruising at the insertion point in the wrist or groin, partly due to the use of antiplatelet drugs; significant haematoma or pseudoaneurysm requiring surgical repair is uncommon. Allergic reaction to the contrast dye is rare with newer agents. Mild transitory deterioration of kidney function is common 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. Sometimes, the angioplasty is not successful in opening up the coronary artery, especially in case of long standing chronically occluded arteries.
Major complications are death, stroke, myocardial infarction and aortic dissection. A heart attack during angioplasty may require emergency CABG. A cardiac surgeon with complete surgical team is on standby during PCI at the Alexandra Hospital to cover this unlikely scenario. The risk of complications in PCI is higher in elderly people above 75 years, presence of kidney disease and diabetes, women, people with heart failure and complex coronary artery disease. Dr Kirk will be pleased to discuss any specific further risks or concerns with you.
Before the procedure
Please bring all your medications with you on the day of the procedure. If you have diabetes, please follow the instructions given to you. If you take Warfarin, you will be given advice for managing your medication before, during and after the procedure. If you have diabetes and are taking Metformin tablets, you should stop taking the tablets the day before your procedure. Do not stop taking other diabetic tablets. Bring your glucose tablets or a snack with you on the day of your procedure. You can drink water, clear tea and black coffee (without milk) up to 2 hours before the procedure. Milk, food, sweets, tea or coffee with milk can be taken up to 6 hours before the procedure. Chewing gum and smoking not permitted on day of surgery. Please take all your regular medication (except metformin) as usual with a sip of water.
Please bring your dressing gown and slippers with you. During your admission, you will be asked to put on a gown and paper pants. Your details will be checked and a name band placed on your wrist. The procedure is performed in Angiography Suite also called Catheter Laboratory, a special x-ray room which looks like a small operating theatre. Just before the procedure, a doctor will again explain the test to you and answer all your questions prior to you signing the consent form for the procedure. A small needle will be put in your arm.
During the procedure
There will be several members of staff in the room during the procedure including a doctor, nurses, a cardiac physiologists a radiographer. During coronary angiogram, you will be kept on your back on an x-ray table. Your heart beat will be monitored using electrodes and ECG machine. The radiographer will move the table and camera into position so that the x-ray pictures can be taken. A local anaesthetic will be used to numb the wrist (less often groin) and usually sedation will be given to help you relax. Once numb the doctor will insert a small tube, called a sheath, into the artery. A guiding catheter is then inserted through the sheath and passed through the artery until it reaches the heart and the origin of the coronary arteries. Low dose x-rays are used to guide the catheter into the right position. Once the catheter is in position a special dye will be injected in the catheter which will flow though your coronary arteries and outline them on an X ray.
The coronary guidewire is then inserted through the guiding catheter into the coronary artery and passed across the narrowing or blockage. With the guidewire is in place, the doctor inserts the balloon catheter on the guidewire and gently pushes it forward until it reaches the blockage. Then the balloon is inflated to compress the plaque and expand the coronary artery to improve the blood flow. Usually, there is a mesh tube (stent) mounted on the balloon catheter is left the artery to keep it open. When the procedure is over, the balloon catheter, guidewire and sheath are removed and an inflatable plastic band is placed on the wrist or pressure device on the groin to keep the puncture site clean and dry.
After the procedure
After the procedure you return to the ward where staff will monitor your blood pressure and pulse. They will also check the wound and circulation of blood in the limb that was used. After a period of resting in bed you will be allowed to get up. Your nurse will keep you informed of your progress. I will explain the results of the angioplasty and tell you about further follow-up. A letter will be sent to your GP confirming this information. You may eat and drink. It is important to drink plenty of fluid as this will help to flush the contrast dye through your kidneys. Providing there are no complications, you will be allowed to go home approximately 2.5 hours after the procedure. If the test was performed via the wrist artery, the dressing can be removed in 24 hours.
During the first 48 hours after your angioplasty your activities should be restricted. To ensure recovery of the artery, you should not do any heavy lifting and bending for the first 24-48 hours. It is normal to feel some discomfort from the wound and a painkiller, such as Paracetamol, is usually helpful. Do not take Aspirin as a painkiller.
You must not drive for 24 hours after discharge. Please arrange for a responsible adult to drive you home and stay with you for 24 hours. If the wound begins to bleed, you or other responsible adult should press firmly over the wound area for 10 minutes.