INTRODUCTION OF ATHERECTOMY
Atherectomy is a minimally invasive endovascular surgery technique for removing atherosclerosis from blood vessels within the body. It is an alternative to angioplasty for the treatment of peripheral artery disease, with no evidence of superiority to angioplasty. It has also been used to treat coronary artery disease, albeit ineffectively.
Atherectomy uses a rotating shaver or other device placed on the end of a catheter to slice away or destroy plaque. At the beginning of the procedure, medications to control blood pressure, dilate the coronary arteries, and prevent blood clots are administered. The patient is awake but sedated. The catheter is inserted into an artery in the groin, leg, or arm, and threaded through the blood vessels into the blocked coronary artery. The cutting head is positioned against the plaque and activated, and the plaque is ground up or suctioned out.
The types of atherectomy are rotational, directional, and transluminal extraction.
INDICATION OF ATHERECTOMY
Indications and Outcomes
Each atherectomy device has a specific set of indications. Rotational atherectomy is the most common atherectomy procedure and is used to treat complex lesions and in-stent restenosis. Directional atherectomy is used rather infrequently but is useful for treating non-calcific ostial lesions. Orbital atherectomy has not been used extensively since it is a new procedure and TEC has fallen out of favor among cardiologists.
- Rotational Atherectomy
- Directional Atherectomy
- Orbital & TEC
- Other Uses for Atherectomy
The indications for the use of rotational atherectomy vary between centers and physicians. Atherectomy can prove useful for particularly difficult lesions and in cases where stenting and angioplasty are not appropriate. According to a multi-center study published in 2004, 24% of rotational atherectomy procedures were for in-stent restenosis. The remaining 74% of rotational atherectomies were for complex lesions.
In-stent restenosis refers to the redevelopment of plaque after the implantation of a stent. This condition is difficult to treat since the stent cannot be removed. Rotational atherectomy is sometimes used to treat this condition. Rotational atherectomy is useful for in-stent restenosis when:
- the areas of restoneses were longer than 15mm
- restoneses created total occlusion of the vessel
The other application of rotational atherectomy is for complex lesions that cannot be suitably treated with angioplasty or stents. The lesions include:
- heavily calcified plaque
- lesions longer than 15mm
- bifurcation lesions (where plaque builds up at a branch point in the coronary arteries)
- total occlusion
Atherectomy can also prove very useful when used before stent placement or angioplasty. Removing atherosclerotic plaque before these procedures relieves stress applied to the artery walls when the plaque in compacted.
The indications for directional atherectomy are more limited and the use of directional atherectomy has mostly fallen out of favor. Some of the possible indications of directional atherectomy include:
- non-calcified ostial lesions
- bifurcations of large arteries
Since directional atherectomy is used so infrequently, no recent studies of its efficacy have been performed. Directional atherectomy will remain a useful tool in the cardiologist’s arsenal, especially for non-calcified ostial lesions.
TYPES OF ATHERECTOMY
Rotational atherectomy uses a high speed rotating shaver to grind up plaque. Rotational atherectomy uses a tiny rotating cutting blade to open a narrowed artery and improve blood flow to or from the heart. Often a stent—a small tube made of metal mesh—is put in the artery to prevent it from re-narrowing.The RA system includes the burr, Rotawire, console, and nitrogen tank. The selected burr size should be approximately 50% of the vessel diameter.2,3 A 6 French (F) guiding catheter can accommodate a 1.25 mm burr. A 7F guiding catheter is the minimum size required for burr sizes ranging from 1.5 mm to 2 mm. An 8F guiding catheter is the minimum size required for the 2.15 mm burr. A 10F guiding catheter is required for a 2.5 mm burr.
Directional atherectomy was the first type approved, but is no longer commonly used; it scrapes plaque into an opening in one side of the catheter. Directional coronary atherectomy (DCA) was originally developed as a potential replacement for balloon angioplasty. The design of the catheter used to perform DCA offered several unique advantages. First, it was capable of removing obstructive atherosclerotic lesions. Thus rather than rearranging plaque within an artery as occurs with balloon angioplasty, the obstruction was relieved by reduction of the plaque mass. Second, certain lesions with characteristics unfavorable for balloon angioplasty appeared to be ideally suited for DCA. Since the atherectomy catheter had a cutting window that could be positioned rotationally as well as longitudinally within an artery, eccentric plaque could be removed selectively. Similar benefits were anticipated from lesions located at important coronary bifurcations, such as those involving the left anterior descending coronary artery and origin of the diagonal branch. Finally, tissue removed by DCA was available for analysis to expand our knowledge about coronary atherosclerosis
Transluminal extraction coronary atherectomy uses a device that cuts plaque off vessel walls and vacuums it into a bottle. It is used to clear bypass grafts.
Performed in a cardiac catheterization lab, atherectomy is also called removal of plaque from the coronary arteries. It can be used instead of, or along with, balloon angioplasty. Atherectomy is successful about 95% of the time. Plaque forms again in 20-30% of patients.Transluminal extraction atherectomy procedures are best suited for clearing out lesions containing both thrombi and plaque, plaque in saphenous vein grafts prior to use in bypass surgery, and blockages that occur in aged bypass grafts. Studies show lower rates of distal embolization and myocardial injury when TEC™ is used before angioplasty as compared to balloon angioplasty alone. With optimal performance, procedural success rates of over 90% have been reached.
ANESTHESIA OF ATHERECTOMY
You will be given a local anesthetic to numb the area where the catheter will be inserted. You will stay awake during the procedure, but be sedated for comfort.
PREOPERATIVE PROCEDURE OF ATHERECTOMY
Before your procedure:
Informed consent is a legal document that explains the tests, treatments, or procedures that you may need. Informed consent means you understand what will be done and can make decisions about what you want. You give your permission when you sign the consent form. You can have someone sign this form for you if you are not able to sign it. You have the right to understand your medical care in words you know. Before you sign the consent form, understand the risks and benefits of what will be done. Make sure all your questions are answered.
An IV is a small tube placed in your vein that is used to give you medicine or liquids.
Local anesthesia is a shot of medicine put into your skin to numb the area and dull the pain. You will also get medicine to keep you calm and relaxed. You may still feel pressure or pushing during the procedure.
PROCEDURE OF ATHERECTOMY
During your procedure:
A small incision will be made in your groin, arm, or wrist. A catheter will be inserted into your artery and moved to the blockage. You may be given dye so your surgeon can see the blockage clearly. He will use a cutting device to remove the plaque from your artery. Your incision will be closed with stitches.
POSTOPERATIVE PROCEDURE OF ATHERECTOMY
After your procedure:
You will be taken to a room to rest until you are fully awake. You will be monitored closely for any problems. You will have a bandage or pressure device on your incision to prevent bleeding. Do not get out of bed until your healthcare provider says it is okay. You will then be able to go home or be taken to your hospital room.
You may need extra oxygen if your blood oxygen level is lower than it should be. You may get oxygen through a mask placed over your nose and mouth or through small tubes placed in your nostrils. Ask before you take off the mask or oxygen tubing.
You may have continuous monitoring of your heart rhythm. Sticky pads placed on your skin connect to an EKG machine that records your heart rhythm.
You will need to lie flat and still for a few hours. You will start to walk 12 or 24 hours after your procedure. Do not get out of bed on your own until a healthcare provider says you can. Ask for help before you get up the first time. Someone may need to help you stand up safely. When you are able to get up on your own, sit or lie down right away if you feel weak or dizzy. Then press the call light button to let healthcare providers know you need help.
Healthcare providers may keep track of what you drink and urinate. Ask how much liquid you should drink each day. Your urine may need to be collected and measured.
- Pain medicine may be given. Do not wait until the pain is severe before you ask for more medicine.
- Antinausea medicine helps calm your stomach and prevents vomiting.
- Antiplatelets, such as aspirin, help prevent blood clots. These medicines make it more likely for you to bleed or bruise.
COMPLICATIONS OF ATHERECTOMY
Minor complications of atherectomy may include:
- Temporary pain
- Minor infections
- Nausea and vomiting
- Reaction to medications or dye
- Allergic skin reaction to tape, dressing, or latex
- Abnormal heartbeat
- Bruising or scarring at the catheter entry site.
These minor complications are temporary in most cases, and are often easily treated by your healthcare providers.
Major Complications Of Atherectomy
There are also several major complications of atherectomy that may occur during or after the procedure. These are uncommon; however, your overall health is a factor in whether these complications will occur. For example, the average risk of having a heart attack during an atherectomy is 5 out of 10,000 patients. In seriously ill patients, the risk increases to greater than 10 in 10,000 patients. In healthier patients, the risk decreases to 1 in 10,000 patients.
Major complications can include, but are not limited to:
- Serious bleeding
- Heart or lung problems, including irregular heart rhythm and lung or heart failure
- Heart attack
- Artery reclosure
- No reflow
- Blood vessel, nerve, or organ damage
- Blood clots
- Failure of medical equipment
- Serious allergic reactions to medication or dye
- Kidney failure, with possible dialysis
- Other rare and unlikely events.
Depending on your situation, a major complication may lead to a longer hospital stay, coronary artery bypass surgery (CABG), intra-aortic balloon pump surgery, or insertion of a temporary pacemaker. In extreme cases, major complications of atherectomy may cause permanent disability or even loss of life. Loss of life with atherectomy, however, occurs in only about 1 in 1,000 surgeries.