About heart attack

The term “heart attack” is always scary to hear. It is no longer just a concern for the elderly but is increasingly striking people across all age groups including young individuals. In England, there are more than 80,000 hospital admissions for heart attacks each year. This number is equal to approximately one individual every six minutes.¹ In 2002 alone, 20,557 people in England and Wales died due to heart attacks, with 19 of them shockingly in the 0-29 age group.²

A heart attack, also known as myocardial infarction, is a life-threatening condition where there is a block of blood supply to the heart. If not treated immediately, this medical emergency may lead to serious damage to the heart muscle and can cause death. Heart attack is primarily caused by a condition called Coronary Heart Disease (CHD). It occurs when the coronary arteries that supply blood to your heart become clogged by fatty deposits also known as plaques. When this plaque becomes unstable and ruptures, it will cause the formation of blood clots that will block the blood flow to your heart. 

The most common symptoms of heart attack that every individual should know are:

• Chest pain characterised by pressure, heaviness, and tightness in your chest. The pain can spread to your left arm or both arms, jaw, neck, and back
• Sweating, lightheadedness, dizziness
• Feeling sick (nausea and vomiting)
• Shortness of breath³

When you feel these symptoms or see people with these symptoms, call 999 or your country’s emergency line and ask for an ambulance immediately. 

Importance of post-heart attack care

While immediate medical treatment is vital during a heart attack, post-heart attack care is also crucial. It is not only about surviving the attack but also about preventing the risk of another attack, reducing the potential complications, and most importantly improving the quality of health of its survivors. Some key things to do after a heart attack include lifestyle modifications, cardiac rehabilitation, and taking the post-heart attack prescribed medication provided by your healthcare personnel.

Antiplatelet drugs will be given to you if you just had a heart attack to reduce the risk of another episode. Platelets are cells in your bloodstream that have a role in blood clotting. Don’t get it wrong, a blood clot is normally a useful function in the human body. For instance, when you accidentally cut yourself, the blood clotting will help you stop the excessive bleeding. However, in some cases including in CHD, platelet and blood clotting will cause problems. 

When plaques rupture, the normal response is to form a clot by activating platelet cells. However, this clot will block the arteries, leading to a heart attack. Antiplatelet drugs play a crucial role in reducing the chance of future attack by preventing this abnormal clotting in your arteries, signalling the platelet not to form a clot.⁴

Types of antiplatelets commonly given

Aspirin

The first and most basic antiplatelet medication used is aspirin (acetylsalicylic acid). Aspirin works by inhibiting an enzyme in platelet (cyclooxygenase-1) activated during clot formation. This will make the platelets less sticky and, therefore less likely to clump together and form clots.⁵

Clopidogrel (P2Y12 inhibitor)

Dual antiplatelet is more beneficial than aspirin alone, thus Dual Antiplatelet Therapy (DAPT) is commonly prescribed. On the platelet surface, there is a receptor that will signal the activation of platelet adherence and clot formation. This receptor is called P2Y₁₂ and the drug that prevents the activation of this receptor includes clopidogrel, prasugrel, and ticagrelor. 

The prescribed DAPT will consist of one aspirin and one of these three drugs. The next question is why do you need this dual prescription? The answer is that two different mechanisms of platelet inhibition will cause a synergistic effect in inhibiting blood clotting. Research shows that using DAPT is more effective than aspirin alone.⁵

How long do you need to take these medications?

After a heart attack, you will be taking aspirin daily and the other antiplatelet typically for a year. How long you have to take a P2Y₁₂ inhibitor (Clopidogrel, most commonly) is tailored to your risk of bleeding and future clots.

• Commonly, after having a heart attack you will be prescribed clopidogrel for a year. If you don’t have a high bleeding risk, it is possible to take it longer
• If you have a bare metal stent and have a high bleeding risk, you might be given this medication for a shorter period. However, if you don’t have a high bleeding risk, it is possible to take it longer
• If you had a Coronary Artery Bypass Graft surgery (CABG), then it is likely to receive this treatment for a year after the surgery^4,6

Risk and side effects

It is important to be aware of how this medication works and what risks it possesses. DAPT increases the risk of bleeding because it works by preventing blood clotting. However, this risk depends on each individual and their health condition. The most common form of bleeding is in your digestive system (stomach and intestines).

Another manifestation is that you can easily bruise and bleed after a usual injury or cut. People with prior bleeding issues, heart failure, high blood pressure, abnormal renal or liver function, and peripheral artery disease will be at a higher risk of bleeding. Some people also experience side effects such as nosebleeds, breathing difficulty, blood in the urine (hematuria), and low platelets in the blood (thrombocytopenia). 

Drug interaction

There are several precautions for possible drug interaction when you take antiplatelet medications. These include 

• Ibuprofen and other painkillers in the same class. They will increase the risk of bleeding when taken together
• Proton Pump Inhibitor (PPI), a drug that suppresses stomach acid, commonly used for Gastroesophageal Reflux Disease (GERD). For example, omeprazole and esomeprazole. There is a study that shows these drugs might prevent the effectiveness of clopidogrel
• Blood thinners (anticoagulants) such as heparin and warfarin can also increase the risk of bleeding

It is important to tell your healthcare provider about your current medications to prevent potential drug interactions.⁴

FAQs

How long should dual antiplatelet therapy be given after a heart attack?

A daily aspirin for life will be prescribed along with one P2Y₁₂ inhibitor (clopidogrel, ticagrelor, or prasugrel) typically prescribed for one year.⁷

Why are antiplatelets used in heart attacks?

Antiplatelet is a drug class that makes the platelet less sticky, inhibiting the formation of a blood clot. Platelets are a type of blood cell that naturally contributes to the clot formation in your body. The most common cause of heart attack is coronary artery disease where plaques formed by fat accumulation rupture and stimulate platelets to form blood clots that lead to a blockage of blood flow to the heart. Using antiplatelets in a heart attack will prevent the risk of another heart attack.⁸

How long do you take clopidogrel after stents?

It depends on several factors including the type of your stent and the risk of bleeding. For drug-eluting stents, the recommended duration is nine months to one year. Bare-metal stents require a longer period of P2Y₁₂ therapy, usually, the recommended duration is 12 months or longer.⁹

Will I be on clopidogrel for life?

Typically, clopidogrel will only prescribed for one year. However, in rare cases, when you can’t take aspirin, you may take one of the other antiplatelet drugs such as clopidogrel for life instead.⁴

Why are antiplatelets high-risk?

Antiplatelet works by naturally inhibiting the function of platelets to form blood clots which will increase the risk of bleeding in your body. It is important to note that in case of a heart attack, the benefits of this medication far outweigh its risks. Therefore, thoughtful consideration is important when weighing the benefits against the risk.

What is the difference between antiplatelet and anticoagulant?

Both the antiplatelet and blood thinners reduce the risk of blood clots. Blood thinner, also known as an anticoagulant, targets the coagulant protein in your blood to inhibit the coagulation process. On the other hand, antiplatelets specifically act on platelets, preventing aggregation and clot formation. Examples of blood thinners include warfarin and heparin, while commonly used antiplatelets are aspirin, clopidogrel, prasugrel, and ticagrelor.¹⁰

What are common indications for the use of antiplatelet therapy?

DAPT is prescribed for people who have had these events and are at risk for future episodes:

• Stroke
• Heart attack (myocardial infarction)
• Transient ischemic attack commonly called mini-stroke

Antiplatelets are also used to prevent thrombosis in people who have had these procedures: 

• Stent placement
• Coronary Artery Bypass Surgery (CABG)
• Angioplasty¹¹

Summary

Antiplatelets are a class of drugs that work by inhibiting the aggregation of platelets and preventing clot formation. These drugs are crucial for patients who have had a heart attack. Two main antiplatelets prescribed post-heart attack are aspirin and a P2Y12 inhibitor, most commonly clopidogrel. 

The duration of antiplatelet therapy varies depending on several factors, like bleeding risk. Typically, you will be taking aspirin daily for life and clopidogrel for 12 months. It is important to note that these medications may have side effects as well, the main concern is the risk of bleeding. However, despite this risk, the benefits offered by this therapy make them essential for patients who just had a heart attack.