Treatment of angina aims to provide immediate relief from the symptoms, prevent future attacks and reduce your risk of further complications.
Specifically, treatment will be used to help reduce your risk of having a heart attack or stroke.
If your risk is thought high, a combination of surgery and medication will probably be recommended. Surgery may also be recommended if medication doesn't work.
If your risk of having a heart attack or stroke is thought low, it should be possible to significantly reduce the risk by using a combination of medication and lifestyle changes (see preventing angina for more information about lifestyle changes).
Immediate relief from symptoms
Glyceryl trinitrate is a medication widely used to provide immediate relief from symptoms of angina. It can also be used as a preventative measure before doing activities known to trigger angina, such as exercise.
Glyceryl trinitrate belongs to a group of medication called nitrates. Nitrates work by relaxing and widening the blood vessels that increase the blood supply to the heart.
Glyceryl trinitrate is available in tablet form, which you dissolve under your tongue, or as a spray. You may experience headaches, flushing and dizziness soon after taking glyceryl trinitrate.
You should avoid drinking alcohol while taking glyceryl trinitrate because it can make the side effects worse. If you experience dizziness, avoid driving and operating complex or heavy machinery.
One dose of glyceryl trinitrate usually eases the pain within two to three minutes. If the first dose does not work, a second dose can be taken after five minutes.
You should dial 999 to request an ambulance if the pain continues for five minutes after taking a second dose of glyceryl trinitrate.
Glyceryl trinitrate tablets usually expire after about eight weeks, at which point you will need a new supply. Therefore, you may prefer to use glyceryl trinitrate spray as it lasts for longer.
Preventing angina attacks
Medication is also used to prevent angina attacks. This will usually involve taking at least one type of medicine every day for the rest of your life.
Your GP or cardiologist (an expert in treating heart conditions) will usually try one medication first to see if it helps prevent your symptoms. This is known as monotherapy. If this isn't effective, two medications may be recommended. This is known as combination therapy (see below).
Firstly, a medication called a beta-blocker or a medication called a calcium channel blocker will be used to reduce the frequency of angina attacks. Which medication is prescribed may depend on your level of health and, in some cases, your personal preference.
Beta-blockers make the heart beat slower and with less force. This means that the heart needs less blood and oxygen after exercise, which can either prevent angina or cut down how frequent it is.
Common side effects of beta-blockers include tiredness, cold hands and feet, diarrhoea and feeling sick.
Beta-blockers can also interact with other medicines, causing adverse side effects. Check with your GP or pharmacist before taking other medicines in combination with beta-blockers, including those available over the counter.
Calcium channel blockers
Calcium channel blockers work by relaxing the muscles that make up the walls of your arteries, increasing the blood supply to the heart.
Side effects of calcium channel blockers include flushed face, headaches, dizziness, tiredness and skin rashes. However, these side effects should pass within a few days once your body gets used to the medicine.
You should never drink grapefruit juice if you are taking calcium channel blockers because they can cause a drop in your blood pressure.
If you are unable to take beta-blockers or calcium channel blockers for medical reasons, or if you find the side effects too unpleasant, your GP or cardiologist may recommend alternative medication.
Long-acting nitrates are similar to glyceryl trinitrate, except they are designed for the long-term prevention of symptoms.
Side effects include headache and a flushed face, although these should improve with time.
If you are taking long-acting nitrates, you shouldn't take the anti-erectile dysfunction medication known as sildenafil (Viagra). This is because the combination of the two can lead to a dangerous drop in blood pressure.
Ivabradine is a newer type of medication that has a similar effect to beta-blockers in that it slows down the speed of your heart beat.
However, it works in a different way to beta-blockers, which means it can often be used in people unable to take beta-blockers for medical reasons, such as those with a lung infection.
A common side effect of ivabradine is that people experience temporary flashes of brightness in their field of vision. If you have this side-effect, it may not be safe for you to drive at night. You should ask your GP for advice.
Nicorandil is a potassium channel activator that works in a similar way to calcium channel blockers, by widening the coronary arteries to increase blood flow to the heart.
However, as potassium channel activators achieve this effect in a different way to calcium channel blockers, they can often be used by people who are unable to take calcium channel blockers for medical reasons.
Side effects of nicorandil include dizziness, headaches and feeling sick.
Ranolazine works by relaxing the muscles of the heart to improve blood flow and prevent angina attacks.
Unlike the other medications used to prevent angina attacks, ranolazine does not affect the speed at which the heart beats, so it may be a more suitable alternative treatment for people with heart failure or an abnormal heart rhythm.
Common side effects of ranolazine include constipation, dizziness and feeling weak.
If a single medication doesn't work for you, a combination of medications will probably be recommended. This is known as combination therapy.
If combination therapy doesn't work, you may be referred for surgical treatment (see below).
In some cases, where people are unable or unwilling to have surgery, or you are waiting for surgery, three different medications may be prescribed.
Reducing the risk of heart attack and stroke
Three medications are available to help reduce the risk of a heart attack and stroke in people with angina. They are:
Statins work by blocking the effects of an enzyme in your liver used to make cholesterol. Reducing blood cholesterol levels should prevent further damage to your coronary arteries and should reduce the risk of a heart attack or stroke occurring.
Statins sometimes have mild side effects that can include, constipation, diarrhoea and abdominal pain.
Low-dose aspirin is a type of medication called an antiplatelet medication. It is used to reduce the 'stickiness' of your blood to prevent blood clots, which can reduce your risk of having a heart attack.
Side effects of low-dose aspirin are uncommon, but can include irritation of the stomach or bowel, indigestion and feeling sick.
If you are allergic to aspirin, or you are unable to take it due to having another health condition that may be aggravated by it, such as stomach ulcer, alternative antiplatelet medications are available.
Angiotensin-converting enzyme (ACE) inhibitors
Angiotensin-converting enzyme (ACE) inhibitors are medicines that can be used to reduce your blood pressure.
ACE inhibitors block the activity of a hormone called angiotensin II, which narrows blood vessels. As well as stopping the heart working so hard, ACE inhibitors improve the flow of blood around the body.
ACE inhibitors have been known to reduce the supply of blood to the kidneys, which can reduce their efficiency. Therefore, blood and urine tests may be carried out before you start taking ACE inhibitors to make sure there are no pre-existing problems with your kidneys.
Annual blood and urine tests may also be required if you continue to use ACE inhibitors.
Side effects of ACE inhibitors include, dizziness, tiredness or weakness and a persistent, dry cough, although these should pass within a few days.
You should check with your GP or pharmacist before taking any other medication in combination with ACE inhibitors as they can cause side effects.
Surgery is usually recommended if your angina symptoms fail to respond to medication. However you will probably need to continue taking some medication after having surgery.
The two main types of surgery used to treat angina are:
- coronary artery bypass graft (CABG) - where a section of blood vessel is taken from another part of the body and used to re-route the flow of blood past a blocked or narrow section of artery
- percutaneous coronary intervention (PCI), also known as a coronary angioplasty - where a narrowed section of artery is widened using a tiny tube called a stent
Coronary artery bypass graft (CABG) or percutaneous coronary intervention (PCI)?
In some circumstances it may not be possible to choose whether you have a CABG or a PCI. For example, PCI may not be suitable for people whose blood vessels have an unusual structure because it can make the PCI technique particularly challenging.
Both PCI and CAGB are broadly similar in their effectiveness in treating angina and preventing fatal complications in the long-term, although each technique has its own set of pros and cons.
As PCI does not involve making major incisions in the body, the recovery time from surgery is much quicker and it involves much less post-operative pain.
One main disadvantage of PCI is that there is a higher risk of the unblocked section of artery becoming blocked again which would require further surgery to treat. The most recent data shows that further surgery is required in around 1 in 25 cases.
CABG is usually the preferred surgical option for people who:
- have diabetes, and/or
- are over 65 years of age, and/or
- have blockages in three or more of the blood vessels that supply the heart with blood
Research indicates that using the CABG technique in such circumstances is more likely to prolong lifespan than using the PCI technique. There is also recent evidence that people who have had a CABG usually report a slightly better quality of life in the long-term.
The disadvantage of CABG is that it causes more post-operative pain than PCI and also has a longer recovery time which is usually around 12 weeks compared to about one to two weeks for PCI.
If treatment is ineffective
If the symptoms of angina do not improve despite medication and surgery (or if surgery is unsuitable), a different approach may be adopted. This may involve use of psychological or behavioural treatments, such as cognitive behavioural therapy (CBT).
Treatments such as CBT can help you develop skills to cope with your condition, manage ain and improve your symptoms.
There are some treatments the National Institute for Health and Care Excellence (NICE) says shouldn't be offered to help manage pain in people with stable angina (angina triggered by physical or emotional stress that usually improves with rest), these are:
- Transcutaneous electronic nerve stimulation (TENS) - where a small, battery-operated machine is used to deliver electrical impulses into the body in order to relieve pain.
- Enhanced external counterpulsation (EECP) - where inflatable cuffs wrapped around the calves, thighs and buttocks are inflated in time with the rhythm of your heart. This is done to help improve blood flow into and out of your heart.
- Acupuncture - a form of ancient Chinese medicine in which fine needles are inserted into the skin at certain points on the body.
These treatments are not recommended because there is a lack of evidence concerning their effectiveness and safety when used to help people with stable angina.
If you have unstable angina (where symptoms develop unpredictably and persist even at rest), upon being admitted to hospital you will be given medication to prevent blood clots developing and reduce your risk of having a heart attack or stroke.
This will usually be aspirin to help thin your blood unless there is a reason you are unable to take it, such as having a history of liver disease.
You will probably also be prescribed another blood-thinning medication called clopidogrel, which you may need to take for at least 12 months (if you are unable to take aspirin you will just be prescribed clopidogrel).
You may also be given an injection of an additional blood thinning medication such as fondaparinux or heparin.
It is likely you will then have a series of tests to assess your risk of having a heart attack in the future (see diagnosing angina for more information).
If the risk is moderately high, an examination called a coronary angiography may be carried out to assess the size and location of the blockage in your coronary artery. If the blockage is significant, coronary artery bypass graft (CABG) percutaneous coronary interventionor or (PCI) surgery can be performed to widen the artery.