- What is atherectomy
- Directional vs Rotational vs Laser Coronary Atherectomy
- Atherectomy procedure
- What happens during the atherectomy procedure?
- How long does the atherectomy procedure last?
- What happens after the atherectomy procedure?
- Atherectomy complications
- Atherectomy prognosis
- Rotational atherectomy
- Rotational atherectomy contraindications
- Rotational atherectomy procedure
- Rotational atherectomy complications
- Directional coronary atherectomy
An atherectomy is a minimally invasive endovascular surgical procedure that utilizes a catheter with a sharp blade on the end to removeatherosclerosis plaque from a blood vessel 1. The catheter is inserted into the artery through a small puncture in the artery, and it is performed under local anesthesia. The catheter is designed to collect the removed plaque in a chamber in the tip, which allows removal of the plaque as the device is removed from the artery. The process can be repeated at the time the treatment is performed to remove a significant amount of disease from the artery, thus eliminating a blockage from atherosclerotic disease.
The goal of atherectomy procedure is to eliminate the build-up of plaque in your arteries.
You may need this atherectomy procedure if your arteries become too narrowed or blocked from plaque inside the artery walls. If arteries are blocked, blood cannot get through to nourish the tissues, causing the muscles of the lower extremities to cramp and lose strength.
An atherectomy is especially helpful for treating blockages in arteries that occur around branches or in vessels that are not easily treated with stents.
Atherectomy procedure is not ideal for everyone. Each patient is evaluated, and treatment will be individualized for the patient’s circumstances.
Atherectomy procedure is performed in the hospital surgical, interventional, or catheterization suite by a trained vascular surgeon.
Directional vs Rotational vs Laser Coronary Atherectomy
Directional coronary atherectomy involves a specially made minimally invasive device with a tiny cutting tip that rotates at high speed to cut away plaque in the artery. A small balloon dilates the blood vessel to improve the efficacy of the procedure and protect the vessel walls. The resected plaque is aspirated and removed from the bloodstream.
Rotational atherectomy is used for particularly difficult or calcified blockages and is the preferred method of preparing a heavily blocked artery for stent placement. The device rotates at extremely high speed, up to 180,000 and as a result, breaks the plaque down to such a small size that it can pass through the bloodstream with no adverse effects.
A laser atherectomy employs a laser light beam in short bursts to vaporize the plaque build-up within the artery. It is often employed for previously failed interventions and when the plaque build-up is not heavily calcified.
The resulting blood flow improvement from any of the above techniques is seen within minutes and is long-lasting. A stent is usually placed in the blockage to enhance results. No general anesthesia is needed and patients can return to normal activity the day after the procedure.
Atherectomy is not performed on every patient with peripheral artery disease. You and your physician will decide whether a directional or rotational atherectomy is right for your circumstance.
A few days before theatherectomy procedure, pre-procedure tests may be performed to ensure that it is safe to continue with the procedure. You may need to discontinue certain medications before the procedure. Your health care team will provide specific instructions to help you prepare.
What happens during the atherectomy procedure?
The atherosclerosis atherectomy will be performed under local anesthesia with a mild sedative given intravenously. Your surgeon will insert a catheter equipped with a sharp blade at its tip and advance it through your artery until it reaches the area of narrowing. Your surgeon will then scrape away the plaque with the catheter blade. The plaque will be collected in a chamber in the tip of the catheter for removal. The surgeon may need to pass the catheter multiple times in order to remove a significant amount of atherosclerosis.
How long does the atherectomy procedure last?
The procedure itself generally takes two hours, but the preparation and recovery time add several hours. Following the procedure, you will need to lie flat for three to six hours. The surgery may require a minimum hospital stay of one to two days.
What happens after the atherectomy procedure?
You can usually begin normal activities again several days after the atherectomy. Your doctor will provide specific guidelines for your recovery.
Your doctor will discuss the specific risks and potential benefits of the recommended procedure with you. Atherectomy usually has no complications, but as with any surgery, there is a risk of complications, such as embolization (the dislodgement of debris that blocks the arteries in the lower part of the leg) and perforation. These complications, however, are rare. An unusual complication of atherectomy is the re-blockage of the artery (restenosis) that may occur later, especially if you smoke cigarettes. Special precautions are taken to decrease these risks, and there may be other possible risks. When you meet with your doctor, please ask questions to make sure you understand the risks of the procedure and why the procedure is recommended.
Atherectomy usually provides good relief of symptoms of atherosclerosis. Your doctor will discuss the results of the procedure with you. However, unless a healthy lifestyle is adopted, atherosclerosis can recur.
Rotational atherectomy is one of several ways to perform atherectomy in a coronary vessel. Rotational atherectomy is the most commonly used atherectomy device and removes atheromatous plaque by differential cutting, that is removing the inelastic calcified plaque with microscopic (20 to 50 micrometers) diamond chips embedded on the surface of a rapidly rotating (150,000 to 200,000 rpm) olive-shaped burr 2. Such abrasion generates 2 to 5-micrometer microparticles that propagate through the coronary microcirculation and are removed by the reticuloendothelial system. The burr travels over a specialized 0.009-inch guidewire and is available in diameters ranging from 1.25 to 2.50 mm. In the setting of severe calcification, smaller burr sizes should be used initially, followed by larger burrs in 0.25 to 0.50-mm increments up to 70% of the reference vessel diameter. David Auth first investigated the possibility of using a rotational device to debulk atherosclerotic plaque in the early 1980s. Fourier et al. 3 performed the first case of rotational atherectomy in human coronary arteries in 1988.
Patients undergoing rotational atherectomy are treated in a similar pharmacological manner to patients undergoing balloon angioplasty. Heparin or bivalirudin is administered to maintain the activated clotting time greater than 300 seconds. One of the potentially disastrous complications of rotational atherectomy is the development of slow coronary flow or no flow phenomena. This is defined as a decrease or cessation of blood flow in the absence of an apparent occlusive dissection or spasm. Slow flow and coronary no flow phenomena are thought to occur as a result of distal microparticle embolization that occurs during rotational atherectomy. It is usually treated with intracoronary administration of verapamil, diltiazem, nicardipine, adenosine or nitroprusside. These medications have their effect at the microcirculation level. Many catheterization laboratories routinely use a cocktail of nitroglycerin, verapamil, and heparin in the flush solution that has been shown to reduce the incidence of spasm and slow/no flow.
Rotational atherectomy is currently used for ostial, and heavily calcified lesions that cannot be dilated with balloon angioplasty or those where the stenosis and calcification are so severe a stent cannot be delivered to its target2. Rotational atherectomy is generally limited to abrasion of superficial calcification with a single burr to improve lesion compliance before the lesion is treated definitively by balloon dilation and stent placement. Rotational atherectomy is used in less than 5% of percutaneous coronary intervention procedures.
There have been numerous nonrandomized reports evaluating the safety and efficacy of rotational atherectomy for the treatment of in-stent restenosis. Most studies performed reported high procedural success rates and low risk of major complications. One of these studies, the ROSTER trial (Rotational Atherectomy versus Balloon Angioplasty for Diffuse In-Stent Restenosis) demonstrated a favorable effect of rotational atherectomy on restenosis, while the multicenter European Angioplasty versus Rotational Atherectomy for Treatment of Diffuse In-Stent Restenosis Trial (ARTIST) did not show a similar beneficial effect.
Rotational atherectomy has also been proposed as a means of treating undilatable lesions that are composed of fibrocalcific plaque. By partially ablating the fibrocalcific plaque, rotational atherectomy can increase lesion compliance and render it more amenable to subsequent adjunct balloon angioplasty and or stent delivery and deployment. Reports of rotational atherectomy being utilized for this type of lesion have reported with a success rate of more than 90%. It has also been suggested that if lesions do not crack despite the use of high-pressure noncompliant balloon dilatations, subsequent rotational atherectomy using small burr sizes can still be performed safely so long as there are no visible dissections within the artery. Rotational atherectomy has also been reported to be successful in a step-wise approach with slow progression of burr size from 1.5 to 1.75 to 2.0 in pulverizing previously deployed multiple layers of stents that have been under-deployed and continue to suffer from significant in stent stenosis. These anecdotal case reports have noted greater than 90% procedural success with minimal incidence of slow or no reflow phenomena.
The main indication for the use of rotational atherectomy at present is to alter lesion compliance in calcified and or undilatable lesions to facilitate stent delivery and expansion. When rotational atherectomy is performed, it should be followed by stenting in most lesions where possible. Overall rotational atherectomy has a firm place in our interventional armamentarium in treating heavily calcified and complex lesions by rendering the procedure simple and effective, but without any effect on restenosis or long-term clinical events 4.
Once the patient is treated, the primary role of patient is to reduce the risk factors for coronary artery disease. This means eating a healthy diet, discontinuing smoking, weight loss, regular exercise, and remaining compliant with medical therapy.
Rotational atherectomy contraindications
Rotational Atherectomy is most effective in calcified, inelastic lesions, it will not be effective in soft and thrombus containing lesions as present in acute myocardial infarction or saphenous vein graft lesions with heavy thrombotic burden where its use is contraindicated 2.
Rotational atherectomy procedure
The rotational atherectomy device consists of a long catheter with an oval-shaped burr that is encrusted with microscopic diamond embedded surface tip. Through the catheter, a lubricious fluid is pumped in to reduce heat production and burr entrapment during the procedure. The proximal end of the burr is smooth and flat at the end. The back end of the catheter is connected to an advancer that allows the operator to extend and retract the burr within the vessel. The advancer is connected to an external console where air or nitrogen is pumped into the advancer through a pneumatic hose to the turbine housed within the advancer to spin the drive shaft and the burr. A foot pedal allows the operator to activate the burr and commence spinning of the burr. The desired rotational speed of the burr is adjusted at the external console.
The coronary guidewire the rotablation catheter rides over has a diameter body of 0.009 inches with a 0.014-inch tip. The burr is advanced over the 0.009-inch portion of the wire, and the larger diameter wire tip restricts its forward motion. While the burr is actively spinning, a wire clip is placed to the back of the wire to it prevent spinning of the guide wire and possibly causing vessel damage. When performing rotational atherectomy, a lubricant consisting of a lubricious lipid emulsion is used to reduce friction between the burr and guidewire is added to the flush bag. The rotational atherectomy lubricant is composed of olive oil, egg yolk, phospholipids, sodium deoxycholate, L-histidine, disodium EDTA, sodium hydroxide, and water.
High-speed mechanical rotational atherectomy relies on plaque ablation and pulverization by the abrasive diamond-coated burr. The rotational atherectomy device can ablate inelastic tissue selectively while maintaining the integrity of elastic tissue due to the principle of differential cutting. Differential cutting is ablating one material selectively while saving and preserving the integrity of another. This is based on different substrate composition, resulting in a polished smooth lumen.
Improvements in technique have included the use of verapamil and nitroglycerin within the flush solution, slow burr advancement, to-and-fro pecking motion of the burr, shorter burr runtimes (15 to 20 seconds), lower burr speeds (150,000 rpm to 160,000), and strict avoidance of significant drops in rpm. These improvements and adjunctive therapies have resulted in significant reductions in the incidence of no-reflow and coronary artery spasm.
Rotational atherectomy complications
As with all atherectomy devices, complications can arise, and this is not exclusive to rotational atherectomy. Based on multicenter registries and numerous observational studies, these complications include death in approximately 1%, myocardial infarction in 1.2 to 1.3%, and emergency CABG in 1.0% to 2.5% of cases. In addition to the clinical complications, the angiographic complications of rotational atherectomy include artery dissection in (10%), abrupt vessel closure (1.8%), a slow-flow phenomenon (1.2% to 7.6%), perforation (1.5%), and severe spasm (1.6%). Another unique but rare complication of rotational atherectomy is dissection caused by wire bias in the angulated lesion, which can be decreased by bending the guidewire or using a small-size initial burr.
In regards to rotational atherectomy burr decelerations, Reisman et al. 5 demonstrated that excessive drops in speed and aggressive advancement of the burr were related to significant increases in temperature and potential thermal injury. In the randomized Study to Determine Rotablator and Transluminal Angioplasty Strategy (STRATAS) trial, decelerations greater than 5000 rpm from baseline for a cumulative time greater than 5 seconds were associated with both an increase in CK-MB elevation and restenosis 6.
There has been a long-standing controversy regarding the use of an aggressive versus a conservative approach for rotational atherectomy. The proponents of the aggressive approach recommended an aggressive burr-to-artery ratio to ablate plaque optimally followed by low balloon inflation pressures to avoid deep tissue injury. The conservative lesion modification approach recommended under-sizing the burr with the goal of altering the compliance of the lesion and facilitating subsequent adjunctive balloon angioplasty (to pressure as needed to obtain a satisfactory angiographic result). In the STRATAS trial, a total of 500 patients were randomized to either:
- An aggressive rotablation strategy where the burr to artery ratio was greater than 0.7 followed by no angioplasty
- A routine or “conservative” rotational atherectomy where the burr to artery ratio was less than 0.7 followed by routine balloon angioplasty.
There was a trend toward a higher initial incidence of greater CKMB elevation and target lesion revascularization as well as angiographic restenosis at 6 to 9 months post procedure in the aggressive strategy group. The CARAT trial (Coronary Angioplasty and Rotablator Atherectomy Trial) enrolled 222 patients into aggressive and conservative groups similar to the STRATAS trial. This study suggested that a routine lesion modification strategy employing small burrs achieves similar immediate lumen enlargement and late target vessel revascularization compared with a more aggressive debulking strategy, but with fewer angiographic complications. Based on these 2 trials, most operators in practice today generally apply a conservative approach and utilize a burr-to-artery ratio of equal to or less than 0.6.
Coronary artery stenting has been associated with lower restenosis rates compared to balloon angioplasty, but stenting of calcified lesions has not been extensively adopted because of concerns about the inability to expand the stent fully due to lesion calcification and rigidity. Because rotational atherectomy changes lesion compliance, better stent expansion is obtained when stents are implanted in calcified lesions following rotational atherectomy. In the Effects of Debulking on Restenosis (EDRES) trial, 150 patients were randomized to stenting alone versus rotational atherectomy with stenting. The results of this study were notable for a reduced binary angiographic restenosis rate at 6 months post-procedure in the rotational atherectomy with stenting group. Also, in the Stenting Post Rotational Atherectomy Trial (SPORT) study, 750 patients were randomized to receive either balloon dilatation or rotational ablation before stent implantation. The mean burr-to-artery ratio was 0.7 plus or minus 0.1 in the rotational atherectomy group. While procedural and clinical success were higher in the rota stenting group, there were no differences in the rates of in-hospital major adverse cardiac events.
Patients with chronic coronary total occlusions have an unacceptable high restenosis rate after revascularization (50% to 70%) after balloon angioplasty alone, and 20% to 30% after stenting. Plaque debulking prior to stenting may render additional benefits by removing the increased plaque burden seen in this type of lesion and also allow for the optimal stent deployment. In general, once the chronic total occlusion has been crossed with the stiff guidewires (then exchanged for the rotational atherectomy wire), the procedural success rates have been close to 100% in all of the recent series with restenosis rates under 30%, which compares favorably to historical controls.
The percutaneous coronary intervention of aorto-ostial lesions and ostial lesions, in general, remain a difficult and challenging task with elevated rates of procedural complications. Due to the ability to pulverize atheroma, professionals believe that rotational atherectomy may result in improved procedural and perhaps even long-term outcomes. There have been several studies assessing these lesions treated with rotational atherectomy. These studies have shown rotational atherectomy (compared to balloon angioplasty) of ostial lesions improves procedural and clinical success and decreases the need for side-branch intervention, while the restenosis rates are favorable in rotational atherectomy and stenting versus stenting alone in these ostial lesions.
Directional coronary atherectomy
Directional coronary atherectomy is a minimally invasive procedure to remove the blockage from the coronary arteries and allow more blood to flow to the heart muscle and ease the pain caused by blockages.
The procedure begins with the doctor injecting some local anesthesia into the groin area and putting a needle into the femoral artery, the blood vessel that runs down the leg. A guide wire is placed through the needle and the needle is removed. An introducer is then placed over the guide wire, after which the wire is removed. A different sized guide wire is put in its place.
Next, a long narrow tube called a diagnostic catheter is advanced through the introducer over the guide wire, into the blood vessel. This catheter is then guided to the aorta and the guide wire is removed. Once the catheter is placed in the opening or ostium of one of the coronary arteries, the doctor injects dye and takes an x-ray.
If a treatable blockage is noted, the first catheter is exchanged for a guiding catheter. Once the guiding catheter is in place, a guide wire is advanced across the blockage, then a catheter designed for lesion cutting is advanced across the blockage site. A low-pressure balloon, which is attached to the catheter adjacent to the cutter, is inflated such that the lesion material is exposed to the cutter.
The cutter spins, cutting away pieces of the blockage. These lesion pieces are stored in a section of the catheter called a nosecone, and removed after the intervention is complete. Together with rotation of the catheter, the balloon can be deflated and re-inflated to cut the blockage in any direction, allowing for uniform debulking.
A device called a stent may be placed within the coronary artery to keep the vessel open. After the intervention is completed the doctor injects contrast media and takes an x-ray to check for any change in the arteries. Following this, the catheter is removed and the procedure is completed.
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