Overview of Angioplasty
Angioplasty is a procedure that helps open blocked or narrow arteries in your heart that are clogged due to a disease called atherosclerosis. This procedure is done by inserting a small tube with a balloon tip through your skin and into the artery. Once this tube is in place, the balloon is inflated to press against the blockage and widen the artery, helping restore normal blood flow and relieve chest pain.
About 40 years ago, doctors used to perform angioplasty with just the balloon (a method called “plain old balloon angioplasty” or POBA). However, POBA had a downside; after the balloon was deflated, there was a chance that the artery could narrow again.
So, to prevent this, doctors started using bare metal stents (BMS). These are small, tube-like metal scaffolds that remained inside the artery after the procedure to provide support and prevent the artery from narrowing again. However, over time, these bare metal stents could cause irritation and inflammation in the artery, leading to it becoming narrow again – a condition known as in-stent restenosis.
To tackle this problem, a new type of stent was developed: the drug-eluting stent (DES). These stents are coated with medication that slows the growth of scar tissue in the artery, reducing the risk of in-stent restenosis. The first-generation DES could potentially cause late-stent blood clotting due to impaired healing of the artery. To overcome this, second-generation DES were developed, which have an additional coating for better healing. Studies have suggested that this version of DES might be safer and more effective in preventing the artery from narrowing again.
Now, a new type of stent called bioresorbable scaffolds system (BRS) is on the horizon. These stents are designed to be absorbed by the body over time, eliminating the downside of having a permanent metallic stent in the artery. However, these stents are still being studied for their full potential and safety, and there may be some issues such as size limitation.
Lastly, for treating small-sized arteries or re-narrowed arteries due to the stents, drug-eluting balloons (DEB) can be an effective treatment. A recent study showed that using DEB in combination with bare metal stents was effective in reducing adverse heart events and late lumen loss (narrowing of the artery long after the procedure). However, this combination was found to be less effective than using drug-eluting stents alone.
Why do People Need Angioplasty
Angioplasty with a stent is a common treatment for individuals suffering from a blockage in the heart’s blood vessels, a condition known as coronary artery disease. When deciding on the type of stent for a patient, it’s vital to consider the patient’s reaction to dual antiplatelet therapy (DAPT). DAPT is a treatment involving two medications to prevent harmful blood clots.
DAPT is an element of concern as the length it’s needed has to ensure sufficient healing around the stent without causing excessive bleeding or clot formation within the stent. Current guidelines recommend that after implantation of a bare-metal stent (BMS), DAPT should continue for at least 1 month, for 6 to 12 months after initial drug-eluting stents (DES), and for at least 3 months after the very latest DES.
Stable angina, a symptom of coronary artery disease, can be managed with drugs and lifestyle changes to control risk factors. The severity of this disease can be determined through certain evaluations, including diagnostic angiography, which involves using a special dye and X-rays to see how blood flows through the arteries.
DES are recommended for patients who can undergo at least 3 months of DAPT. However, for patients at high risk of bleeding, those who cannot continue DAPT for a month after receiving the stent, or those who might need surgery within a month of stent placement, the bare-metal stent (BMS) would be the preferred option.
If surgery is planned between one and three months after stent placement, the choice between a BMS and DES might depend on the availability of a specific coating for the stent and the patient’s risk for re-narrowing of the artery (restenosis).
People who have a hard time following their treatment plan should ideally get a BMS. And in situations where the patient is already taking blood thinners for a condition like atrial fibrillation, a specific type of stent with a BA9 coating in combination with a month-long DAPT may be considered.
For patients with a high risk of bleeding, another option is using a single antiplatelet therapy after DES, especially if the BA9-coated stent isn’t available. A BMS might be an option for blood vessels that are less likely to experience re-narrowing or for patients with high bleeding risks.
For patients likely to experience re-narrowing in their arteries, an additional option may be to close off the left atrial appendage – a small pouch in the heart where blood clots can form – and continue with the DAPT more safely.
Preparing for Angioplasty
When a stent, a small tube used to treat narrowed or weak arteries, is implanted in the body, its metallic surface can cause blood clotting issues. This is a concern because acute vascular closure, or the abrupt blockage of a blood vessel, could occur due to a ruptured plaque, activated blood clotting cells (platelets) and the discharge of tissue factors during and after the angioplasty procedure. Angioplasty is a procedure to restore blood flow through the artery.
To stop this from happening, the procedure is usually performed under anticoagulation, which is a way of thinning the blood to prevent clot formation. The challenge lies in finding a balance for the risk of blood clots and the risk of bleeding complications at the site where the stent is accessed. These may arise due to the use of several anticoagulation agents, like heparin, bivalirudin and other blood thinners. Bivalirudin normally has a lower risk of bleeding complications, blood platelet reduction and death, but it may slightly increase the risk of a clot forming in the stent compared to heparin. However, heparin can sometimes cause heparin-induced thrombocytopenia (HIT), or a reduction in platelets. If a patient has previously experienced HIT, then bivalirudin is used.
Before surgery, the area on the thigh or wrist being operated on is cleaned and the patient is provided with an anesthetic for relaxation. An incision is made, the artery is punctured and a sheath is introduced. This is all assisted with x-ray imaging.
There may be occasional instances when a more complex blockage is discovered. In such cases, the blockage needs to be handled before the stent is inserted, in order to ensure ideal delivery of the stent, its expansion and reduced chances of plaque embolization, or blockage caused by particles breaking free from the plaque. The methods that can help achieve this include atherectomy (removing plaque from blood vessels), use of a specialized balloon, a mini catheter and therapies for excessive plaque calcification. A technology called Optical Coherence Tomography (OCT) is used to guide accurate stent placement.
How is Angioplasty performed
There are two main methods to perform an angioplasty, a treatment for a heart attack. These are the transfemoral and the transradial approaches. The type of procedure chosen depends on the patient’s condition and the expertise of the medical team.
Transradial Approach
The transradial approach goes through the radial artery, which is close to the surface of the skin and can be easily accessed. This approach does not pose a high risk of injury to nerves or blood vessels, as these are not located nearby. However, this artery is quite small, requiring small catheters.
Though the transradial approach is cost-effective and usually results in an earlier release from the hospital, there are some downsides. It might take longer to perform and carry the risk of radiation exposure. Variations in the patient’s anatomy could also contribute to the failure of the catheterization. Additionally, spasms in the radial artery can occur, but these can be resolved with medication such as nitrates and calcium channel blockers. Heart surgeons use the Allen’s test or pulse oximetry examination to assess the blood flow in the hand via the ulnar artery.
Transfemoral Approach
The transfemoral approach is the more traditional procedure and has the advantage of easy access. This approach also has a shorter radiation time and uses less contrast agent. However, complications are more likely to occur, especially in overweight patients. These complications can include bleeding at the access site, hematoma (a swelling filled with blood), significant internal bleeding that requires a blood transfusion, the formation of an arteriovenous fistula (an abnormal connection between an artery and a vein), and injuries to the nerves or blood vessels. Because the femoral artery is the only blood supplier to the leg, ischemia (a lack of blood flow) can occur more often compared to the transradial approach.
Possible Complications of Angioplasty
In rare cases, a serious complication can occur during a procedure called angioplasty, in which a blocked blood vessel is repaired. This complication, known as coronary artery perforation (CAP), happens when a hole accidentally forms in the heart’s artery. This might result from a guide wire, an oversized balloon, or certain surgical devices used during the procedure. This complication affects between 0.1% and 0.8% of all angioplasty patients.
Treatment options for CAP depend on how severe the damage is, the patient’s overall condition, and the type of CAP, which is classified in three levels. Type 1 is usually not harmful, while type 3 is more serious and can require emergency heart surgery. Mild CAP can be managed by reversing the effects of the blood-thinning medication used during angioplasty, inflating a balloon in the artery for an extended period, or inserting a covered stent (a small mesh tube placed in the artery) or blocking the area with fat particles. However, using a covered stent could lead to stent thrombosis (a blood clot) and in rare cases, a coronary arteriovenous fistula (an abnormal connection between a coronary artery and a vein) has been reported. CAP can lead to a heart attack and cause fluid accumulation around the heart, leading to unstable blood pressures that may require emergency drainage.
In-stent restenosis (ISR) refers to the narrowing of the artery after angioplasty. ISR occurs due to different reasons based on the type of stent used in the procedure. It could happen immediately due to the vessel’s natural reaction or occur later due to new cell growth within the stent. Further, stent failure can lead to ISR and blood clot formation. Irrespective of the cause, ISR usually presents with chest pain or symptoms that mimic a heart attack due to the lack of blood supply to the heart’s muscle, and it may need to be fixed with another angioplasty or even bypass surgery. The rates of ISR vary, with higher rates in the past, but in recent times, they have dropped to less than 10% due to improved stent designs and technology.
What Else Should I Know About Angioplasty?
Coronary heart disease, or CHD, is a common health concern for elderly people worldwide. CHD is a condition where the heart’s blood vessels become narrow or blocked, often due to a buildup of plaques (a mixture of cholesterol, other fats, calcium, and a blood-clotting material called fibrin). In the United States alone, over 15.5 million individuals have this disease, according to updated data for 2016 from the American Heart Association.
CHD is a leading cause of serious health issues and death in developed countries like the United States. Almost one in every three deaths in people over 35 years old can be traced back to this heart condition.
However, the good news is that the death rate from CHD has been slowly decreasing over the past several years. This is largely because of a specific medical procedure known as percutaneous coronary intervention with stenting. This procedure involves inserting a small mesh tube, called a stent, into the blocked artery to keep it open. This intervention, often referred to as angioplasty, has been a significant development in the efforts to reduce the severity and death rates associated with CHD.