Interventional Cardiology is that branch of cardiology that specifically deals with diagnosing and treating cardiovascular diseases which includes congenital (present at birth) as well as acquired- like coronary heart disease, valvular heart diseases, cardiomyopathies, pericardial diseases etc through catheter-based procedures, such as angioplasty, stenting etc.
A number of procedures can be performed by catheterisation of heart and vessels: the coronary artery, peripheral artery or vein, the renal artery, although the commonest is the coronary artery. It involves insertion of a sheath into the radial or femoral artery and cannulating the heart under the x-ray vision (fluoroscopy). The radial artery has the advantage of easy control of bleeding in anti-coagulated patients, increased comfort levels as early mobilisation is possible.
Interventional cardiology offers an advantage of avoiding scars and pain and long post-operative recovery period.
Primary Angioplasty, the most rewarding interventional cardiology technique is now the gold standard of treating acute myocardial infarction (acute heart attack). It involves extraction of clots from the blocked coronary arteries with or without deployment of stents. It preserves the pumping function of the heart, so that the patient will have less chances of heart failure in future.
At Columbia Asia Hospitals, we offer interventional cardiology treatment options. Our cardiologists are trained in premier institutions in India and abroad and periodically update their skills to practice contemporary medicine. Evidence-based medicine and following international treatment protocols is the hallmark of the department.
- Angioplasty: also called percutaneous coronary intervention (PCI) for treatment of coronary artery disease.
- Valvuloplasty: for dilatation of narrowed cardiac valves, which help regulate the blood flow through the chambers of the heart.
- Congenital heart defect correction: like atrial and ventricular septal defects- device closures, device closure of patent ductus arteriosus and angioplasty of greater
- vessels- aorta/ PA branches
- Percutaneous valve replacement: an alternative to open heart surgery
- Per cutaneous valve repair on the mitral and pulmonary valve
- Coronary thrombectomy which involves removing of a blood clot from the coronary arteries
- Peripheral Vascular Disease intervention which involves the other arteries like renal, carotids, subclavian, mesenteric, femoral or distal lower limb vessels
Anatomy Of The Heart
The human heart is a little bigger than the fist and is located just behind the sternum or breast bone, a little to the left. The heart pumps blood to the various parts of the body and receives blood with carbon dioxide, which is pumped to the lungs for oxygenation.
The heart has four chambers; the right atrium, right ventricle, the left atrium and left ventricle.
Blood from the body and head enters the right atrium of the heart through a large vein, the vena cava. From here, blood passes to the right ventricle to the lungs where it loses the carbon dioxide and gets more oxygen. It then returns to the left atrium of the heart, from where it flows to the left ventricle and thereafter to the various parts of the body and brain. There is a bundle of nerves in the wall of the right atrium called the sinus node from which electrical impulses enable the pumping action of the heart.
What Is Radial Artery Catheterisation?
Cardiac catheterisation is most commonly performed by entering the circulatory system through a blood vessel in the groin (the femoral artery). However, the procedure is also performed through the radial artery which courses through the wrist.
Catheterisations through the radial artery have several advantages:
- The patient comfort is high and as the entry site is at the wrist, patients are able to sit up and walk immediately after their procedure. Patients having their procedures via the femoral artery approach will often require up to six hours of bed rest. As result, there are fewer issues with back discomfort and patients are able to eat comfortably after their procedure.
- The patients who are scheduled for same day discharge can be discharged at an earlier time period than if their procedure was performed through the femoral approach since the post procedure recovery is shorter than with the femoral approach.
- The radial approach is safer than the femoral approach for majority of patients undergoing cardiac catheterisation. The radial artery is smaller and very close to the skin, therefore bleeding is significantly reduced compared to the femoral approach.
Prior to deciding the route, your physician will examine your wrists and ensure you are a good candidate for the radial artery approach and determine which wrist will be utilised for the procedure. The physician will administer a local anaesthetic at your wrist and this is generally the only discomfort during the procedure. Once the arterial catheter is placed in the artery, your arm will be brought by your side. A medication will be administered that helps prevent spasms or narrowing of the radial artery. This medication can give a warm, burning sensation in the hand and arm and this generally resolves within seconds. At the conclusion of the procedure, a transparent inflatable wrist band will be placed around the catheter entry site and will be left in place for at least two hours. A nurse or technician will assess your wrist prior to removing the band and your wrist will be further watched for an hour. Your physician may ask that you avoid activities that are strenuous on your wrist for at least 48 hours. The activities include lifting heavy objects and paddle sports. The majority of patients will be back to simple activities such as writing immediately after their procedure.
What Is A Drug-Coated / Drug Eluting Stent?
A stent is a mesh metal tube inserted after angioplasty to keep the artery propped open. Drug-coated stents (also called drug eluting stents) provide an additional benefit; they slowly release a medication that blocks cell proliferation and prevents scarring during the first few weeks after insertion, when scarring is most likely to occur. With traditional stents, about 20% of patients who undergo angioplasty experience restenosis – scarring of tissue around the stent – which can narrow or block the artery again. The use of a drug-coated stent dramatically lowers the patient’s risk of needing another procedure due to restenosis.
When is it indicated?
Drug eluting stents are recommended only if the artery to be treated is less than 3 mm in diameter or the affected section of the artery is longer than 15 mm.
Angioplasty or balloon angioplasty is a non-surgical, endovascular procedure to widen narrowed or blocked arteries or veins, typically to treat arterial atherosclerosis. An empty, collapsed balloon is passed over a wire into the narrowed locations and then inflated to a fixed size. This expands the vessel and its muscular wall and opens up a blood vessel to improve blood flow.
Angioplasty is a vascular intervention that is typically performed in a minimally invasive or percutaneous method. In addition to ballooning, a stent may also be placed during angioplasty. This procedure is performed in a cath lab by an interventional cardiologist assisted by trained nurses and technicians.
Also called percutaneous coronary intervention (PCI), it is a treatment for narrowed or blocked coronary arteries, which are caused by build-up of cholesterol laden plaques. PCI for stable coronary artery disease reduces chest pain, but does not reduce the risk of death, myocardial infarction or other major cardiovascular events.
This is a procedure where a balloon is used to open up a blood vessel other than the coronary arteries. It is done to treat narrowing due to atherosclerosis of the abdomen, leg or renal arteries. It is done in conjunction with peripheral stenting and atherectomy.
Carotid stenting is done for carotid artery stenosis in patients who are at high-risk for carotid endarterectomy.
Renal artery angioplasty
This is done for atherosclerotic narrowing of renal artery with or without stenting. Renal artery stenosis can cause hypertension and loss of renal function.
This is done for stenosis of the subclavian vein caused by thoracic outlet syndrome.
- When the access vessel (either the femoral or radial artery) is insufficient in size
- Small size, posterior calcification, occlusion, haematoma or a bypass origin all render a vessel unfit for angioplasty access
Preparation for angioplasty
- A history of past and present complaints will be taken.
- Information regarding all medication including herbal etc. will be collected.
- Test for allergy to any medication will be conducted.
- You may be asked to stop aspirin, blood thinners and non-steroidal, anti-inflammatory drugs for a specified time before angioplasty.
- If one is pregnant, the doctor should be informed.
- If you are on blood pressure medications, you will be advised to take them as usual on the morning of the angioplasty with sips of water.
- You may be asked not to eat or drink anything for a few hours before the procedure.
- A nurse or technician will insert an IV line through which sedatives and other medication as required will be given.
- You will be hooked onto a monitor to gauge your heart rate, blood pressure and other vital parameters.
- The areas of your body where the catheter is to be inserted will be shaved, sterilised and covered with a surgical drape.
- Your doctor will numb the area with a local anaesthetic.
- A very tiny skin incision is made.
- Access is usually percutaneous i.e. through the skin. An introducer sheath is inserted into the blood vessel and after injecting a radio-opaque contrast dye is used to guide angled wires and catheters to the region of the body to be treated. To treat the narrowing, a wire is passed through the stenosis and a balloon is passed over the wire and inflated with water mixed with contrast dye. The positioning is verified by fluoroscopy. After the procedure,the balloon, wires and catheter are removed and vessel puncture is sealed.
- Several types of interventional procedures may be used for angioplasty.
- Balloon angioplasty: A specially designed catheter with a small balloon tip is introduced up to the blocked point in the artery and then inflated to compress the plaque and dilates the artery, increasing the blood flow to the heart.
- Stent:a small metal mesh that acts as a scaffold to support the coronary artery. Sometimes a drug eluting stent is used to reduce the risk of re-stenosis. The doctor will determine if this type of stent is appropriate for your type of blockage.
- Rotablation: A special catheter with an acorn shaped, diamond-coated tip is guided to the blockage. The tip spins at a high speed and grinds away the plaque. The debris is washed away in the blood and filtered by the liver and spleen. This is repeated to ensure adequate blood flow. This procedure is rarely used today because balloon angioplasty and stenting have much better results and are technically easier for the cardiologist to perform.
- Atherectomy: The catheter used in this procedure has a hollow cylinder on the tip with an open window on one side and a balloon on the other. When the catheter is inserted into the narrowed artery, the balloon is inflated, pushing the window against the plaque. A blade (cutter) within the cylinder rotates and shaves off any plaque that protruded into the window. The shavings are caught in a chamber within the catheter and removed. This process is repeated as needed to allow for better blood flow. Like rotablation, this procedure is rarely used today.
- Cutting Balloon: The cutting balloon catheter has a special balloon tip with small blades. When the balloon is inflated, the blades are activated. The small blades score the plaque and then the balloon compresses the plaque against the artery wall.
- Much less invasive than bypass surgery
- Lower cost than surgery
- Done under local anaesthesia whereas surgery requires general anaesthesia
- Only a small nick is made and no other surgical incision
- You can return to normal activities much faster after surgery.
Risks and complications
- Tear of the artery
- Heavy bleeding from the site of access
- Embolisation or launching of debris into the blood stream
- Arterial rupture from over-inflation of balloon or use of an inappropriately large or stiff balloon or presence of a calcified vessel
- Haematoma or pseudo-aneurysm formation at the access site
- Rarely, radiation injuries from x-rays used
- A relatively rare complication associated with balloon angioplasty is abrupt vessel closure or occlusion. This happens within 24 hours of the procedure.
- Rarely heart attack and sudden cardiac death
- Infection at the puncture site
- Contrast dye may cause renal failure or a decreased renal function, especially if renal function was already compromised.
Recovery after angioplasty
Post angioplasty, patients will be sent home the next day if there are no complications. The puncture site is checked for bleeding and sheath is removed. Patients will be asked to walk around after 2-6 hours and return to normal, non-strenuous activities in a week. After two weeks, patient can begin low level exercises. A graduated programme with initially performing low and short bouts of exercises and gradually increasing it is advised. All exercise programs should be discussed with your cardiologist.
Patients with stents are usually prescribed aspirin and anti-platelets.
Inform your doctor if you have:
- Swelling, bleeding or pain at the puncture site
- Weakness or feel faint
- Chest pain
- Change in temperature or colour of the limb used for angioplasty
Limitations of angioplasty
- Angioplasty cannot cure or reverse underlying atherosclerosis, which has to be treated by exercise and medications
- Accompanying lifestyle modification such as dietary changes, exercises, stop smoking and limit alcohols are required
- Associated treatment of diabetes and hypertension is needed
- In those who undergo renal angioplasty, in many cases smaller vessels have already been damaged and hence, blood pressure control is limited
- In those with peripheral vascular diseases, stenting is less successful if multiple leg vessels are affected and when small vessels have to be opened. Accompanying smoking cessation, healthy diet and cholesterol control is vital
- In carotid stenting, often a filter device is placed to prevent blood clots and plaques from passing into the brain
The coronary arteries supply blood to the heart muscle. They become clogged due to build-up of atheromatous plaques and can reduce blood flow to the heart. If a clot blocks the blood flow, it can lead to a heart attack.
An angiogram is an x-ray test that uses dye to visualise the arteries. Normally, the arteries cannot be seen in an ordinary x-ray and when an iodin--based dye is used as a contrast media, the arteries can be visualised. A coronary angiogram is the 'gold standard' for evaluation of coronary heart disease. It is used to identify the exact location and severity of the coronary heart disease.
How is an angiogram used to diagnose cardiovascular disease?
A coronary angiogram is performed with the use of local anaesthesia and intravenous sedation. Cardiac catheterisation is a test used to evaluate your coronary arteries and heart valve function. It identifies the size and location of plaques that may have built up in your arteries from atherosclerosis, the strength of your heart muscle and the adequacy of valve function. In cardiac catheterisation, the interventional cardiologist threads a catheter (thin flexible hollow tube of 2-3 mm) through a blood vessel in your arm or groin and into your heart. The vessels can be visualised by a fluoroscope, which is special x-ray viewing equipment. With the catheter in place, the cardiologist can measure blood pressure, take blood samples and inject dyes containing iodine into your coronary arteries or arteries elsewhere in your body to trace the movement of blood through the arteries and chambers of the heart. By observing the movement of the dye through your heart's chambers and blood vessels, the cardiologist can see whether the arteries are narrowed or blocked and whether the valves are working properly. This helps determine whether you may need bypass, valve surgery, angioplasty or catheter-based valve repair.
Angiogram can look at the arteries of the heart (coronary angiogram), lung (pulmonary angiogram), brain (cerebral angiogram), head and neck (carotid angiogram), legs or arms (peripheral) and the aorta (aortogram).
An angiogram can be used to locate a bulge in a blood vessel (aneurysm) or narrowing or blockage in a blood vessel affecting blood flow.
What does a coronary angiogram show?
- Angiogram images accurately reveal the extent and severity of artery blockages including tear in a blood vessel causing internal bleeding or weaknesses in blood vessel wall (aneurysm).
- For those with severe angina, heart attack or abnormal stress tests, an angiogram is done to find out the extent and location of blockages.
- Detects changes in the blood vessels of injured or damaged organs
- Shows the pattern of blood flow to a tumour, extent of spread and guides treatment
- Shows the condition, and location of blockages of the renal artery
- Helps in detection of blocks on diseased blood vessels of the leg in peripheral artery disease
- Checks on severity of atherosclerosis of coronary arteries
- In some cases, a method called interventional radiology may be used during an angiogram to treat diseases. For example, a catheter can be used to open a blocked blood vessel, deliver medicine to a tumour or stop intestinal bleeding caused by diverticula haemorrhage. To stop intestinal bleeding, the catheter is moved into the small artery where the bleeding is occurring and medicine that narrows the artery or causes the blood to clot is injected through the catheter.
What types of procedures do interventional cardiologists perform?
- Angioplasty and stenting: A long, slender tube is inserted through a blood vessel in your leg or wrist and guided to the heart or elsewhere in your body. A dye is injected through the arteries to guide the cardiologist during the stenting procedure. A balloon at the tip of the catheter is inflated to stretch open the artery and restore increased blood flow to the heart. In most cases, a small metal mesh cylinder called a stent is then placed in the vessel to help keep it open.
- Atherectomy: Devices with tiny blades are sometimes used to cut away plaque deposits caused by atherosclerosis inside the blood vessel.
- Carotid stenting: Similarly, balloons and stents can be used to open the carotid arteries, the main blood vessels to the brain, and thereby lessen the risk of stroke.
- Embolic protection: In some cases, particularly when the narrowing being treated is in a bypass graft or in the carotid arteries, filters and other specialised devices are used to help ensure that pieces of the plaque don’t break off and travel in the blood to cause damage.
- Percutaneous mitral valve repair: A catheter is introduced through a blood vessel in your leg and guided through a vein to the heart. Smaller catheters holding a special clip is guided into place and positioned near to, or actually attached to the mitral valve to make it function properly.
- All test reports, history, allergies, medication and clinical examination is done.
- Blood tests including coagulation profile, renal and liver function tests are done.
- An appointment is fixed for angiogram.
- You will be asked not to eat anything for a few hours before the procedure, as a sedative is usually advised.
- You may be advised to stop anticoagulants.
- Advise on other medication will depend on your specific case.
- An intravenous line will be inserted into a vein to deliver sedatives and any other medication as required.
- Electrodes will be placed on your chest to record heartbeats.
- A blood pressure monitor may be attached to your arm.
Will be done when patient comes with an acute coronary syndrome or a heart attack
- Following angiography, the catheter will be taken out.
- Direct pressure will be applied on the puncture site for about 10-15 minutes to make sure there is no bleeding.
- If the procedure is done by the femoral route, you will be asked to lie on your back for several hours.
- You will be observed for any bleeding at the puncture site.
- If there is no bleeding, the sheath covering the puncture site will be removed.
- You will be advised to drink fluids in a short while. It may take up to 12 hours before you can resume normal work. Patient usually leave the same day or the next day.
- Your doctor will discuss the results with you.