Cardiac catheterization and angiography is an invasive procedure, used to investigate the structure and function of the heart. It is also used to test for any narrowing of the coronary arteries (arteries that supply blood to heart muscle). The procedure is performed with the use of X-ray guidance.
Importance of Procedure:
Cardiac catheterization can provide in-depth and specific information about various cardiac diseases. Coronary angiography can provide a clear picture of the severity and location of narrowing in the coronary arteries. Treatment (percutaneous intervention using balloon and stenting) of these narrowings may occur immediately. Treatment may even be deferred pending further patient and Heart Team discussion, depending on the lesion/disease complexity and patient stability.
In emergency situations i.e. in the setting of an acute coronary syndromes (heart attack), the procedure is important in diagnosis and immediate, life-saving treatment of the problem (usually a blocked artery).
Cardiac catheterization, despite its invasiveness, can be life-saving and the consequence can be detrimental, unreasonably delayed.
Before the procedure, some preliminary tests may be performed, including electrocardiogram and blood tests. We will also check your allergy history. These can be performed days before the procedure or on the day of admission.
- Blood thinning drug (warfarin) or diabetic drug (metformin) may have to be stopped several days before the procedure.
- Special anti-platelet drug should be taken if PCI is also planned. If a stent has been placed, Clopidogrel 75 mg daily for one year will need to be taken in combination with aspirin in order to prevent stent closure (thrombosis, a potentially fatal complication).
- Medical authorization will be required for uninterrupted monthly administration of clopidogrel. Chronic forms will require completion for clopidogrel administration. Do not interrupt medication, even if authorization has not been granted. CONTACT YOUR DOCTOR IMMEDIATELY.
- Steroids will be given if there is a history of contrast allergy.
- An intravenous drip may be set up. Shaving may be required over the puncture site.
- If you are a female, please provide your last menstrual period (LMP) and avoid pregnancy before the procedure as this procedure involves exposure to radiation.
- This procedure is performed under local anaesthesia in a cardiac catheterization laboratory (cath. lab). You are awake during the procedure, but will be given a light sedative, i.e Valium 2.5 mg – 5 mg, to calm you down and to allow you to relax and to prevent a condition called radial artery spasm. In the event of respiratory distress, you may need to be anaesthetized and ventilated, acutely.
- Electrodes are placed onto the chest wall to monitor the heart rate and rhythm.
- Blood oxygen monitoring via your finger tip will be set up using a SATS probe. Measurement of blood pressure from your arm or leg will occur during the procedure.
- A small wound is made over the groin, or wrist for access to arteries or veins.
- Catheters are advanced to the heart under X-ray guidance following guide-wire insertion (see coronary intervention procedure below).
- Diagnostic coronary angiography involves the catheter being advanced to the coronary arteries, followed by dye (contrast) injection to visualize the coronary artery anatomy. (See Simultaneous coronary intervention below).
- Pressures within the heart are measured. Blood samples may be drawn from various heart chambers to determine their oxygen saturation in the case of a full heart study.
- During the procedure, you may be asked to hold your breath or cough. You may experience a hot flush feeling when contrast is injected, especially during left ventriculogram/aortogram.
- You may experience mild palpitations or vague chest discomfort. The discomfort should not be severe.
- Fractional flow reserve is a technology using a pressure-wire to assess the significance of a coronary lesion. Should a coronary narrowing be severe, percutaneous coronary intervention may be performed if feasible.
Simultaneous Coronary Intervention:
When indicated, percutaneous coronary intervention (PCI) will be performed in the same setting of cardiac catheterization and coronary angiogram.
If any significant narrowing or blockages are found, then a tube with a tiny wire is passed down the affected artery so that a sausage-shaped balloon can be passed over it and into the part that is narrowed or blocked. To open up the artery, the balloon is inflated with fluid, which then presses against the plaque, pushing it out of the way, and also fracturing it.
Most of the time, one or more stents may be placed into the artery to help keep the artery open. A stent is a metal tube or spring coil which is passed into the diseased part of the artery using a balloon. The balloon is removed once the stent is in place. The stent stays in for life.
After the procedure, you will be given drugs, which reduce your risk of blood clotting and the stent blocking (dual antiplatelet therapy).
At the end of the procedure the artery may be closed with a special plug to stop the bleeding (see risk and complication below).
Other procedure that may be required
- Rotablation: to drill away hard calcium plaques which may hamper balloon tracking.
- Temporary pacemaker insertion via the left or right groin vein to speed up the heart rate.
- Pericardiocentesis: In case of blood collecting around the heart
- DC cardioversion: Should the heart rate speed up due to an arrhythmia
- Intra-aortic balloon pump: May be required to assist with cardiac function and to augment blood pressure.
Risk and Complications
Common Risks and Complications:
- The procedure carries certain risks. Minor complications include allergic contrast reaction, nausea, and groin complications (bleeding, haematoma).
- Uncommon Risks with Severe Consequences: Total major complications account for 1.7%. These include heart attack (0.05%), stroke (0.07%), perforation of heart chamber (0.03%), aortic dissection, death (0.1%), and severe bleeding.
- Other major complications include arrhythmias, vascular complications (possibly requiring surgical correction), anaphylactic reactions to contrast and hemodynamic complications.
- Should a complication occur, another life-saving procedure or treatment may be required immediately, such as coronary artery bypass grafting, emergency pericardiocentesis, temporary pacemaker insertion or intra-aortic balloon pump insertion to support the cardiac output and blood pressure.
- Blood transfusion may be administered during or after my procedure should the need arise.
- An blood HIV test may be performed in the unfortunate occurrence of a needle stick injury.
Please do not feel alarmed about the mention of these risks. They are indeed rare and it is the doctors' responsibility to mention them to you. However, feel reassured that the doctors take the utmost of care to prevent them occurring.
After the Procedure
- After the procedure, catheters will be removed. The wound site will be compressed to stop bleeding. Doctors usually deploy a vascular closure device (Angio-seal device) to stop bleeding, if the procedure occurred femorally (leg artery).
- Radial artery institutional protocols will apply for radial access. A pressure band will stop bleeding in the arm.
- Nursing staff will check your blood pressure, pulse and wound regularly.
- Bed rest may be necessary for few hours (4-6 hrs). Please do not move or bend the affected limb for 4-6 hours after the procedure if performed via the leg. If your wound is over the groin, please apply pressure with your hand over the wound when you cough or sneeze so as to prevent re-bleeding.
- You should inform your nurse if you find blood oozing from the wound site.
- You will probably be able to go home (usually the same day) after that, but someone else will need to drive you. If your doctor fixes the blockages in any of your arteries, you will probably need to stay in the hospital overnight. After the coronary angiogram, you will need to rest and take things easy for approximately a week. You will not be allowed to drive for the next 5 days after the procedure. Your doctor will make a follow-up appointment to see you in about 6 weeks for a review.
When should I call my doctor or nurse?
Call your doctor or nurse if any of the following happen after your cardiac catheterization
- The area where the tube went in bleeds a lot. The nurse or doctor may need to apply more leg pressure. If angiography occurred via the radial artery, then the pressure band may need to be re-inflated.
- You get a fever or have pain, swelling, or redness where the tube went in. These symptoms could mean that you have an infection.
- Your leg or arm is weak or numb.
- If the arm becomes unbearably painful. Conditions to be excluded include arm ischaemia, haematoma, radial artery dissection (tear) or compartment syndrome.
- You have a recurrence of chest pain
Usually you can be discharged the same day, or more safely, one day after the procedure if intervention has occurred. The wound will be inspected and covered with light dressings.
Please keep the wound site clean and change dressings if wet. In general, showering is allowed after 1-2 days. Please avoid vigorous activities (household or exercise) in the first few days after the procedure. Bruising around the wound site is common and usually subsides. If you notice any signs of infection, increase in swelling or pain over the wound, please come back to the hospital or visit a nearby Accident and Emergency Department immediately. Dr. Hendrickse will discuss the results of the procedure before discharge. Should you have further questions, you and your close relatives can discuss with Dr. Hendrickse during subsequent follow-up.
It is hard to mention all the possible consequences if this procedure is refused. The list of complications is not exhaustive and other unforeseen complications may occasionally occur. Please feel free to contact Dr. M.C Hendrickse for any major queries.