Coronary angioplasty and stent implantation are two of the most common procedures performed in the United States. The procedure is not surgery. It is a catheterization. A small hollow tube is inserted in to the femoral (leg) or radial (wrist) artery and moved under x-ray guidance to the heart where it is used to measure pressure and inject dye to directly visualize the heart's blood supply. Catheterization from the leg is the most common way to perform the procedure.
A patient needs a catheterization when he is having a heart attack or has chest pains suggestive of low blood flow to the hear muscle (angina). If angina symptoms cannot be treated with medications in stable outpatients, a catheterization is indicated. It can only be performed at hospitals that have specialized x-ray facilities and a dedicated team of nurses and technicians. Prior to any catheterization, I explain the potential risks of the procedure to every patient and family. It is important that the patient understand complications are possible. The most common risks are bleeding and discomfort at the site of catheterization. Serious complications include vascular injury, allergic reaction, kidney damage, stroke, heart attack and injury to the heart that could be life threatening. All of the serious risks are less than 1 percent. It is important that you understand these possible risks and discuss them with your cardiologist before the procedure.
The procedure starts with cleaning the groin or arm with a special solution to prevent infection. A small needle is used to inject anesthetic at the site of catheterization; this is typically the only discomfort a patient will feel and is over quickly. A light sedative might be given prior to the local anesthetic.
The first catheter inserted is a sheath. This allows the cardiologist to place different types of catheters into the arteries, as sometimes the most common catheters don't work for every patient. The size of the sheath and diagnostic catheters is typically 2mm in diameter. The injection of the arteries with dye is typically painless, but some patients might feel chest tightness transiently. If you feel severe discomfort, itching or trouble breathing it is important to let the team know because it might be a sign of a complication or allergic reaction.
After taking six to eight pictures, the cardiologist may perform an intervention or angioplasty. This requires a special type of catheter which might require a larger sheath. Intravenous blood thinners are given prior to starting an angioplasty. This injection might cause some burning at the intravenous site in the arm. A small wire (0.014 inch diameter) is inserted into the artery and across the blockage. This wire becomes the rail for delivering balloons and stents to the area of interest. When the balloon is inflated in the artery, brief chest pain may be felt. In rare cases, a simple balloon angioplasty is adequate. It is typical to insert a stent after the balloon.
A stent is a small metal tube that is deployed into the artery wall to improve its expansion and cover the area injured with a balloon. Before stents were available, may patients had to return to the cath lab in the middle of the night because the artery closed abruptly. A larger number of patients (approximately 40 percent) required a repeat procedure to treat re-narrowing inside the artery at the site of angioplasty within 6 to 12 months. Stents virtually eliminated the risk of abrupt closure after angioplasty. The chance of re-narrowing is dependent upon many factors and is better than balloon angioplasty alone.
Many patients receive drug coated stents. These stents have a very low chance of re-narrowing after insertion, approximately 5 to 10 percent. In 2006 and 2007, these stents were in the news because of safety concerns. Currently, the data suggested that these stents are as safe as the older conventional bare metal stents, assuming the patient can take aspirin and clopidogrel (Plavix) for at least 6 to 12 months. The choice of stent used is many times a very crucial part of the success of the procedure, and it is important that your cardiologist know in advance if you have conditions that would prevent you from taking the prescribed medications.
After the stent implantation, many patients have a vascular closure device inserted. This is often a type of collagen plug to reduce the time spent flat in bed. The conventional approach is to remove the catheter after the blood thinners have worn off. This is followed by compression of the catheterization site by a nurse or technician. After sheath removal, it is common to spend 4 to 6 hours flat in bed. Most patients go home the day after angioplasty. It is typical to have minor bruising and discomfort in the groin for a week after the procedure. It is usually recommended to avoid heavy lifting or strenuous exertion for a week after a cardiac catheterization.
Understanding Cardiac Catheterization
Nov 18, 2009 | By
