Overview of Rotational Atherectomy
Calcium deposits within your heart’s arteries could suggest previous swelling, scarring, or healing. These deposits are linked to significant heart disease, specifically atherosclerotic coronary artery disease. You can imagine it like a buildup of plaque on these arteries. This plaque hardens and narrows your arteries, which reduces the blood flow to your heart muscles.
This sort of calcification can spread widely within your heart’s arteries. If it becomes significant, doctors might not be able to widen the artery using conventional treatments like balloon angioplasty. Sometimes, permanently placing a tiny wire mesh tube called a ‘stent’ in an artery to improve blood flow might also not be successful because it could end up causing the stent to clot, form hardened plaque around it (restenosis), or even break.
Doctors use equipment to go inside the artery to remove this calcium or to modify the hardened plaque (atheroma). The most common method is called ‘Rotational Atherectomy’. This involves using a small device equipped with diamond chips. This device rotates extremely fast (150,000 to 200,000 times per minute) and dislodges the hardened area. The device travels over a very thin guiding wire and is available in various sizes that range from 1.25 to 2.50 mm in diameter.
The idea of using this rotational method to remove hardened plaque was first investigated in the early 1980s. However, the first procedure using this method in human coronary arteries was carried out in 1988.
Remember, severely calcified arteries require careful treatment starting with smaller devices, followed by larger ones. Overall, this process improves the space within the arteries and allows better blood flow.
Why do People Need Rotational Atherectomy
Rotational atherectomy is a technique used to treat complicated blocked arteries or those heavily packed with calcium deposits that are too stiff to be opened up using typical balloon angioplasty, or too blocked for a stent to be placed where it’s needed. This technique mainly works by scraping away superficial calcium deposits with a rotating device. It aims to make the lesion, or damaged area, more flexible before it’s treated more definitively with balloon dilation and the placement of a stent, which is a small tube to keep the artery open. Despite its usefulness, rotational atherectomy is used in less than 5% of all non-surgical procedures to open up blocked arteries.
When a Person Should Avoid Rotational Atherectomy
Rotational Atherectomy is a type of procedure that works best for treating areas in the body that have become hard and stiff due to calcification—a process that involves the buildup of calcium in body tissue. However, it isn’t effective for softer areas or where there are clots (thrombus), like in certain heart conditions such as acute myocardial infarction—a term for a heart attack—or in cases where a vein graft from the leg (saphenous vein graft) has developed a large amount of clots. Using this technique in these instances is not recommended.
Equipment used for Rotational Atherectomy
The rotational atherectomy device is a special tool used by doctors for removing hardened material, called plaque, from your blood vessels. This device has a long tube with a tip shaped like a tiny oval brush, which is covered in microscopic diamond particles. This tip is what helps soften and remove the plaque.
In order to keep the device cool and free-moving during the procedure, a special fluid is pumped through the tube. This fluid also prevents the tip from getting stuck. The part of the tip near the tube is smooth and flat.
The back of the tube is connected to a device that moves the tip forwards and backwards inside the blood vessel. This is further connected to an external machine that controls the air or nitrogen supply, which in turn spins the tip. The doctor can control the spinning of the tip and adjust its speed using a foot pedal and some controls on the external machine.
The rotational atherectomy device is guided by a wire which is a lot thinner than a strand of your hair, having a diameter of 0.009 inches and a tip that’s slightly thicker at 0.014 inches. This thicker tip acts as a stop to prevent the device from moving further than needed. When the device is in use, the wire is held firmly in place to prevent it from spinning along, which could potentially harm the blood vessel.
To make the procedure smoother, a special lubricant is added to the fluid pumped through the device’s tube. This lubricant, similar to a very slippery substance made from olive oil, egg yolk, and other ingredients, reduces friction between the device and the guiding wire.
Preparing for Rotational Atherectomy
When patients are having a medical procedure called rotational atherectomy, which is similar to balloon angioplasty, they are given certain medications in much the same way. This includes heparin or bivalirudin, and these are used to help the blood’s natural clotting process take more than 300 seconds, effectively thinning the blood to prevent clots.
One of the potential severe complications that can arise during this procedure is the development of what’s called slow coronary flow or no flow phenomena. Simply put, this is when the blood flow in the arteries of the heart slows down or stops, even if there’s no blockage or spasm that’s clearly causing it. It’s believed that this happens because of small particles embolizing, or spreading out, during the atherectomy process.
Treatment for this usually involves giving the patient medications such as verapamil, diltiazem, nicardipine, adenosine or nitroprusside directly into the coronary artery. These medications tend to work more on the microcirculation level, or the smallest blood vessels in the body. Many labs that perform these procedures typically use a mix of nitroglycerin, verapamil, and heparin in a flush solution, as it has been shown to reduce the chances of spasms and slow or no blood flow incidents.
How is Rotational Atherectomy performed
High-speed mechanical rotational atherectomy is a type of heart surgery. It uses a device equipped with a small, abrasive, diamond-coated cutter to break down and remove hard, unhealthy plaque in the arteries. This device can identify between tougher, less flexible tissue (which it needs to remove) and more flexible, healthy tissue (which it needs to keep safe). This is called differential cutting.
This method is precise because it identifies tissues based on their composition. As a result, it creates a smooth interior for your blood vessels, reducing the risk of future blockages.
Modern updates to this procedure have made it safer and more effective. These improvements include using drugs like verapamil and nitroglycerin to relax the arteries, moving the cutter forward gently and steadily, doing short cutter rotations (only 15-20 seconds each), and maintaining a consistent cutter speed. Breaking the cutting process into small parts, known as the “pecking motion,” also lowers the risk of complication. These changes have significantly reduced the risk of little-to-no blood flow and arterial spasms, making the surgery safer for you.
Possible Complications of Rotational Atherectomy
Just like any other medical procedure involving the removal of plaque from the arteries, complications might unfortunately occur when performing a rotational atherectomy. Information acquired from several research centers and studies have shown that these complications can lead to outcomes like death in about 1% of cases, heart attacks in 1.2 to 1.3% of cases, and emergency coronary artery bypass surgery (CABG – a type of surgery that improves blood flow to the heart) in 1.0% to 2.5% of cases.
Moreover, there can be complications seen during the angiographic process (a type of X-ray used to check the blood vessels). These could include artery dissection (unwanted tearing of an artery) seen in 10% of cases, sudden vessel closure (1.8% of cases), a phenomenon called “slow-flow” (1.2% to 7.6% of cases) which is a reduced blood flow through the affected artery, perforation (1.5% of cases), and severe muscle spasm in the artery (1.6% of cases).
There’s also a very uncommon complication specific to rotational atherectomy where unwanted tearing in the artery can be caused by wire bias in the angled lesion. This issue can be minimized by bending the guide wire used in the procedure or by using a smaller initial burr (a rotating tool used to clear material).
What Else Should I Know About Rotational Atherectomy?
Rotational atherectomy is a procedure used to unblock clogged heart arteries. It works kind of like a drill to gently remove blockages. However, too much speed or pushing the drill too hard can cause the area to heat up and potentially cause damage. A trial by Reisman and other scientists found that abrupt drops in speed or pushing the drill too hard were linked to these unsafe temperature increases.
There’s an ongoing debate about whether a full-on attack or a cautious approach is better for this procedure. Some recommend using a large drill (also known as a burr) and softer balloon inflations to avoid damaging deep tissue, while others recommend using a smaller burr to alter the blockage’s structure and make it easier for an accompanying balloon angioplasty to work (that’s a procedure to widen the artery). An experiment, the STRATAS trial, had patients try both methods. The results pointed towards the full-on attack method causing more damage initially as well as higher rates of the blockage reoccurring later down the line.
A follow-up test, the CARAT trial, also had patients try both techniques. The results suggested that the cautious approach gave similar results to the full-on attack method, but with fewer complications. Today, most doctors prefer the cautious strategy using a burr that’s smaller than or equal to 60% of the artery’s size.
The practice of installing a sort of scaffold, or ‘stent’, to keep the artery open, causes fewer blockages to come back compared to using a balloon alone to widen the artery. However, tough, calcified (or hardened) blockages can be difficult for the stent to fully expand against. Rotational atherectomy alters these blockages, making them more pliable and allowing the stent to expand properly. A trial called EDRES had patients opt for a stent alone or the rotational atherectomy before the stent. The results showed fewer incidences of the blockages re-showing in the group who had the rotational atherectomy first.
A similar trial, SPORT trial, also showed that the procedures and success were higher in the group with rotational atherectomy. However, both groups had similar rates of major heart-related events while in the hospital.
With some serious heart blockages, the rates of them coming back are worryingly high – 50% to 70% after a balloon procedure alone, and 20% to 30% after a stent. By drilling down on the blockage before putting in a stent, less plaque is present, and the stent can work better. Studies have shown nearly 100% success rates and blockages coming back at rates of under 30%, which is a marked improvement over past results.
Where heart arteries join onto the main artery, the aorta, dealing with blockages can be tricky and complicated. Thankfully, because rotational atherectomy can turn blockages into dust, experts believe the procedure may improve both short-term and long-term effects. Several studies treating such joinings with rotational atherectomy have shown improved success rates and less need for intervention on side arteries. They also showed that using rotational atherectomy with stents gives better results than stents alone in these joinings.
