The Benefits and Risks of Treatment

Cardiovascular Health and Risk

What is the main learning objective of 1C.7 The Benefits and Risks of Treatment?

Know the benefits and risks of treatments for CVDs, including antihypertensives, statins, anticoagulants and platelet inhibitory drugs.

What treatment options are available once a patient shows signs of cardiovascular disease?

Lifestyle changes such as improving diet, stopping smoking and exercising more, as well as drug treatments.

What is the overall aim of drugs used to treat cardiovascular disease?

To reduce the risks associated with CVDs by helping prevent further problems from developing.

Why must the benefits and risks of CVD treatments be considered?

All medicines can provide benefits but also carry risks and may cause side-effects.

What is hypertension?

Blood pressure that is regularly higher than 140/90 mmHg.

Why is controlling hypertension important?

Hypertension is a major risk factor for cardiovascular disease and can also damage organs such as the kidneys and eyes.

Define antihypertensive.

A drug that reduces high blood pressure.

What are the main types of antihypertensive drugs?

Diuretics, beta blockers, sympathetic nerve inhibitors and ACE inhibitors.

How do diuretics reduce blood pressure?

They increase urine production, removing excess water and salts from the body, decreasing blood volume and therefore lowering blood pressure.

Why does decreasing blood volume lower blood pressure?

A smaller volume of blood is pumped through the blood vessels, reducing the pressure exerted on their walls.

Define a diuretic.

A drug that increases the volume of urine produced.

How do beta blockers reduce blood pressure?

They reduce the heart's response to hormones such as adrenaline, making the heart beat more slowly and with less force.

What effect do beta blockers have on heart rate?

They reduce heart rate.

What effect do beta blockers have on the force of heart contractions?

They make contractions less forceful.

Why do beta blockers lower blood pressure?

A slower heart rate and less forceful contractions reduce the pressure at which blood is pumped through the arteries.

Define a beta blocker.

A drug that blocks the response of the heart to hormones such as adrenaline.

What does the sympathetic nervous system normally do to arteries?

It stimulates arteries to constrict, which raises blood pressure.

How do sympathetic nerve inhibitors reduce blood pressure?

They prevent sympathetic nerves from signalling the arteries, helping the arteries remain dilated and therefore lowering blood pressure.

Define sympathetic nerve inhibitors.

Drugs that inhibit sympathetic nerves, keeping arteries dilated.

What effect does angiotensin have on blood vessels?

It stimulates blood vessel constriction, causing blood pressure to rise.

How do ACE inhibitors reduce blood pressure?

They block the production of angiotensin, reducing blood vessel constriction and therefore lowering blood pressure.

Define an ACE inhibitor.

A drug that blocks the production of angiotensin.

What is the benefit of antihypertensive drugs?

They lower blood pressure, reducing the risk of CVD and reducing damage to organs such as the kidneys and eyes.

What is one major risk if antihypertensive treatment is not carefully monitored?

Blood pressure may become too low.

Why can excessively low blood pressure be dangerous?

It can cause falls and injuries, particularly in elderly patients, and can potentially be life-threatening.

What are some possible side-effects of antihypertensive drugs?

Coughs, swollen ankles, impotence, tiredness, fatigue and constipation.

Why might patients stop taking antihypertensive medication?

High blood pressure may cause no obvious symptoms while medication may cause noticeable side-effects, making the treatment seem worse than the disease risk.

How can perceived risk affect whether a patient continues antihypertensive treatment?

A patient may focus on noticeable drug side-effects and underestimate the larger but less visible risk of untreated hypertension and CVD.

Define a side-effect.

A secondary, usually undesirable effect of a drug or medical treatment.

What must be demonstrated before a drug is licensed for use?

The benefits of the treatment must be judged to outweigh its potential side-effects and risks.

Why should CVD medication be evaluated using both benefits and risks?

A treatment may reduce the risk of serious disease while simultaneously causing harmful side-effects.

What are statins?

A group of drugs that lower blood cholesterol levels.

How do statins reduce blood cholesterol?

They block an enzyme in the liver involved in cholesterol production.

How do statins affect LDL production?

They are very effective at reducing the production of LDLs.

How do statins affect the LDL-to-HDL balance?

They improve the balance of LDLs to HDLs.

How else can statins reduce atherosclerosis besides reducing LDLs?

They reduce inflammation in the lining of arteries.

How do statins reduce the risk of atherosclerosis?

They reduce LDL production, improve the LDL-to-HDL balance and reduce inflammation in artery walls, decreasing plaque development.

Why can statins reduce the risk of cardiovascular disease?

Lower LDL levels and reduced atherosclerosis decrease the likelihood of coronary artery disease, heart attacks and other CVDs.

Do statins benefit all groups equally?

No. They reduce serious cardiovascular disease in many groups but may have a greater effect in some high-risk groups than others.

Why may statins have a greater benefit in people with low HDL levels?

Low HDL is associated with a poorer LDL-to-HDL balance and increased CVD risk, so improving this balance can provide a greater benefit.

What did the UK statin study described in the textbook compare?

Middle-aged men taking a statin with men taking a placebo.

What was the risk of heart attack or death from heart disease in men taking the statin in the UK study?

11.8%.

What was the risk in men taking the placebo?

15.5%.

What does the UK statin study suggest?

Statins reduce the risk of heart attack or death from heart disease.

What happened after participants in the UK statin study stopped taking the drug?

Some protection against heart attack or death remained for up to 10 years.

What is a placebo?

An inactive substance resembling the drug being tested that is used as an experimental control.

Why are placebos used in drug trials?

They allow researchers to compare people receiving the active treatment with people receiving an inactive treatment, helping determine whether changes are actually caused by the drug.

Why should participants ideally not know whether they are receiving a drug or placebo?

Knowing which treatment they receive could affect their behaviour, expectations or reporting of symptoms and therefore bias the results.

Why might a placebo-controlled trial become ethically difficult?

If strong evidence emerges that the active drug substantially reduces serious disease, continuing to withhold it from the placebo group may put those participants at unnecessary risk.

What are common side-effects of statins?

Muscle and joint aches, nausea, constipation and diarrhoea.

Are serious statin side-effects common?

No. Serious side-effects are possible but very rare.

What rare serious muscle problem can statins cause?

Severe muscle inflammation, which can potentially be fatal.

What rare organ problem can statins cause?

Liver damage.

Why must the risks of statins be compared with their benefits?

Rare serious side-effects must be weighed against their ability to significantly reduce the risk of cardiovascular disease.

What behavioural risk may occur when people take statins?

They may believe the medication protects them completely and stop trying to maintain a healthy diet.

Why is taking statins not a substitute for a healthy lifestyle?

Statins lower cholesterol but do not protect against all harmful effects of an unhealthy diet or other CVD risk factors.

Define statins.

Drugs that lower cholesterol levels in the blood.

What are plant stanols and sterols?

Compounds structurally similar to cholesterol that can reduce blood cholesterol when consumed.

Where are plant stanols and sterols commonly added?

Products such as spreads and yoghurts.

How do plant stanols and sterols lower blood cholesterol?

They reduce the amount of cholesterol absorbed from the gut into the blood.

How does reduced cholesterol absorption affect LDL levels?

Less cholesterol enters the blood, making it easier for the body to metabolise cholesterol and reduce LDL levels.

How much plant sterol or stanol does the textbook say should be consumed for an effect?

About 2 g per day.

What effect can about 2–2.5 g of plant sterols per day have on LDL cholesterol?

It can reduce LDL cholesterol by approximately 10%.

How much may plant stanols and sterols reduce the risk of heart disease when used correctly according to the textbook?

About 25%.

Are plant stanol and sterol products classed as drugs?

No. They are sold as foods.

Why should evidence about plant stanols and sterols be evaluated carefully?

Although evidence suggests they are effective, they have not undergone the same level of testing required for licensed medicines such as statins.

What does a meta-analysis of plant sterol studies provide?

Evidence combining results from multiple studies, which can give a more reliable estimate of their effect.

What is an anticoagulant?

A substance that reduces the ability of blood to clot.

Why might anticoagulants or platelet inhibitory drugs be given after heart surgery or thrombosis?

To reduce the risk of harmful blood clots forming.

What is warfarin?

An anticoagulant that interferes with the production of prothrombin.

What is prothrombin?

A protein involved in the blood-clotting process.

How does warfarin reduce blood clotting?

It interferes with prothrombin production, so the blood clots less easily.

Why must warfarin dosage be carefully controlled?

Too much can prevent blood from clotting sufficiently and cause dangerous internal bleeding, while too little may fail to prevent harmful clots.

Why is warfarin sometimes described as a poison?

In sufficiently high doses it prevents normal blood clotting and can cause severe or fatal bleeding.

Does warfarin completely prevent blood clotting at a therapeutic dose?

No. The dose is controlled so clotting is reduced but not completely prevented.

Why must patients taking warfarin be monitored carefully?

Doctors must maintain a balance between preventing harmful clots and allowing normal clotting when necessary.

What serious complication can occur if anticoagulation is excessive?

Internal bleeding, particularly bleeding in the brain.

What factors influence whether a patient should receive warfarin?

Their age, medical condition, risk of clotting, risk of bleeding and other medications they are taking.

Define anticoagulant.

A substance that interferes with blood clotting.

What are platelet inhibitory drugs?

Drugs that reduce blood clot formation by preventing platelets from clumping together.

How do platelet inhibitory drugs reduce clot formation?

They make platelets less sticky, reducing platelet aggregation and therefore decreasing the blood's ability to clot.

Define platelet inhibitory drugs.

Drugs used to prevent blood clots by preventing platelets from clumping together.

What is a common example of a platelet inhibitory drug?

Aspirin.

What is another platelet inhibitory drug mentioned in the textbook?

Clopidogrel.

How does aspirin help reduce cardiovascular disease risk?

It reduces platelet aggregation, making harmful blood clots less likely to form.

What is a major advantage of aspirin as a CVD treatment?

It is relatively cheap and effective at preventing many cardiovascular problems in suitable patients.

What is a major risk of aspirin?

It can irritate the stomach lining and cause gastrointestinal bleeding.

Why can aspirin-related stomach bleeding become serious?

Reduced platelet activity makes it more difficult for bleeding to stop.

What is a possible benefit of combining aspirin and clopidogrel?

The combination can further reduce the risk of cardiovascular events in some patients.

What is a possible disadvantage of combining aspirin and clopidogrel?

The risk of serious bleeding can increase.

Why does a treatment that benefits high-risk patients not necessarily benefit low-risk patients?

In low-risk patients, fewer cardiovascular events are prevented, so treatment side-effects may become large relative to the benefits.

What did the textbook example show for high-risk patients treated with aspirin and clopidogrel?

For every 1000 high-risk patients treated for 28 months, five cardiovascular events would be avoided but three major stomach bleeds would be caused.

What did the textbook example show for lower-risk patients?

For every 1000 lower-risk patients, 23 cardiovascular events would be avoided while 10 major bleeds would be caused.

Why should treatments sometimes be targeted at high-risk groups?

The potential benefit is greater in people with a high initial disease risk, making it more likely that the benefits outweigh the side-effects.

Why is individual patient risk important when deciding whether to prescribe a CVD drug?

The balance between benefits and side-effects differs depending on the patient's underlying risk of disease.

What is meant by the risk-benefit balance of a treatment?

Comparing the expected health benefits of treatment with the probability and severity of its harmful effects.

What factors should be considered when evaluating a CVD treatment?

How effectively it reduces disease risk, the frequency and severity of side-effects, the patient's original risk, dosage, monitoring requirements and available alternatives.

Why should medication not automatically be given to everyone at some risk of CVD?

For lower-risk individuals, the probability of treatment side-effects may be too large compared with the number of cardiovascular events prevented.

Why is monitoring important when using cardiovascular drugs?

It helps ensure the treatment remains effective while preventing dosage-related complications such as excessively low blood pressure or dangerous bleeding.

Compare antihypertensives and statins.

Antihypertensives primarily reduce high blood pressure, whereas statins primarily lower blood cholesterol and reduce atherosclerosis risk.