What is a kidney transplant? - Blood pressure, cholesterol, heart disease and circulation problems
- Circulation problems are important complications after transplantation
- Stopping smoking is the most important preventative action anyone can take
- Exercise and a healthy diet are important
- Treatment of the blood pressure and cholesterol with drugs are often needed
In this part of the website, several different problems have been brought together, but they are all closely interconnected. They are all problems with the circulation – that is, the blood vessels all around the body. The blood vessels that come out of the heart to supply the body, called the arteries, are under particular strain because a lot of blood flows through them. The walls of the arteries are stretched and put under pressure each time the heart beats.
Over many years, this stress can lead to damage to the arteries, which occurs much faster if the blood pressure is high or if there is too much fat (particularly one type of fat called cholesterol) in the blood. Damaged arteries can cause disease in all parts of the body, most particularly in the heart itself (heart attack), in the neck and brain (causing stroke),or in the legs (gangrene).
About 30% (one in three) of the population of the UK will develop serious circulation problems, so of course these could occur in someone whether they were transplanted or not. However, research has shown that circulation problems are commoner in transplant patients than in the general population. Some of this risk comes from the development of circulation problems on dialysis, or from periods of high blood pressure before kidney failure developed. Diabetes is also a cause of circulation problems.
Blood flows around the body from the heart, under pressure generated by the pumping action of the heart. The exact level of this pressure can be measured from the arm. The blood pressure varies from minute to minute, and is meant to rise to high levels under strenuous exercise.
However, in many people with kidney problems, the blood pressure remains high all the time. This is a particular problem after a transplant, because some of the anti-rejection drugs make the blood pressure higher. At least half of transplant recipients have high blood pressure, usually with no symptoms. Some people are also born with a tendency to develop high blood pressure which is why it is so common in the general population.
Blood pressure is measured by two numbers. These give the highest pressure of blood in the pulse as the heart pumps blood out (known as the systolic blood pressure), and the lowest pressure in between heartbeats (the diastolic blood pressure). The Renal Association (the society for British kidney doctors) recommends that transplant recipient’s blood pressure should ideally be lower than 130/80 mmHg. However, many people cannot achieve this target blood pressure, despite taking several types of drug to lower the blood pressure. This may be because drugs cause side effects, or because there is some hardening of the arteries in the blood and a higher blood pressure is required to get blood around the body, or because the blood pressure is higher when measured in clinic than it is in day to day life (sometimes called the white coat affect). The medical team in the transplant unit need to assess the best achievable blood pressure in individuals according to these factors. A 24 blood pressure monitoring test may be required or you may be asked to keep a daily record
Cholesterol is a type of fat. It is carried around in the blood so that it can be sent to parts of the body to be used for energy or as building blocks for the body’s organs. The level of cholesterol in the blood varies between individuals – some people are born with higher cholesterol levels than others. In addition, if there is more fat in the diet, the higher the cholesterol level. Lastly, the anti-rejection drugs given to transplant patents also cause high cholesterol levels.
The ideal cholesterol level is less than 5 mmol/l, but not everyone with a level higher than this needs special treatment.
High cholesterol and high blood pressure can be treated with lifestyle changes, dietary changes and with drugs. The lifestyle changes include regular exercise and stopping smoking. Dietary changes include a generally healthy diet without too much salt or fat. Drug treatments for high blood pressure or cholesterol are frequently needed in transplant patients, and the doctors will advise each individual case. Many of these drugs have side effects, so if a new tablet causes problems, the doctors should be told straight away. It is usually possible to stop it and try an alternative.
Narrowings can slowly develop in the walls of arteries. The strain that occurs each time the heart beats and pumps blood out stretches the wall of the artery and can cause minor damage to its lining. This damage usually repairs itself, but sometimes cholesterol from the blood enters the damaged area and forms a small thickening in the wall of the artery. Over a long period of time, this can get larger and larger so that eventually the artery may become blocked. If the blood pressure or the cholesterol levels are high, this damage will occur faster.
Common problems caused by narrowing of arteries include heart attack. This occurs because, although the heart pumps all the blood around the body, it also needs its own blood supply. This comes from the coronary arteries, which run over the outer surface of the heart. The coronary arteries are normally quite small, and are prone to the development of narrowings. If the heart muscle itself becomes starved of blood by a blockage it may become irreversibly damaged and weakened, and this is a heart attack.
Stroke may occur either if a blood vessel in the brain bursts, or if there is severe disease in the arteries leading to the brain, causing a blockage. A stroke is damage to the brain. In many cases there is good recovery, in some cases the ability to move one side of the body may be affected.
In some cases, the blood vessels to the legs can become blocked, causing gangrene (black flesh) in the toes or feet.
There are several important things that can be done to reduce the risk of circulation problems after a transplant. The most important is to stop smoking. This can be difficult because of addiction to nicotine, but help with nicotine patches, hypnotism and even acupuncture can all help people to give up.
A healthy diet and regular exercise will help, and making sure that the weight does not go up too much after a transplant. It is all too easy to become overweight after a transplant, when the dreadful dietary restrictions of dialysis are lifted.
Drugs can help reduce the risk of circulation problems, including blood pressure and cholesterol treatment. Many transplant patients are also prescribed a small aspirin tablet to take every day. This thins the blood and reduces the chances of arteries blocking.
The National Kidney Federation cannot accept responsibility for information provided. The above is for guidance only. Patients are advised to seek further information from their own doctor.