Cardiac Implications of Thrombotic Thrombocytopenic Purpura

Introduction:

Thrombotic thrombocytopenic purpura (TTP) is a rare but life-threatening blood disorder that involves the formation of small blood clots in blood vessels, blocks the blood flow to several vital organs, including the heart, and can have significant cardiac implications. TTP can have a variety of cardiac effects, including arterial thrombosis, accelerated hypertension, acute myocardial infarction (MI), atrial fibrillation, and congestive heart failure. This article briefly explains thrombotic thrombocytopenic purpura with a focus on its cardiac implications and management.

What Is Thrombotic Thrombocytopenic Purpura?

Thrombotic thrombocytopenic purpura (TTP) is a rare condition characterized by the formation of blood clots (thrombi) in small blood vessels throughout the body. These clots can cause severe health problems by blocking blood vessels and restricting blood flow to vital organs, including the brain, kidneys, and heart.

In TTP, the term thrombotic means the formation of blood clots, thrombocytopenic means the low platelet count, and purpura means the appearance of purple spots or bruises on the skin. TTP involves the sudden formation of many small blood clots (thrombi) form suddenly throughout the body.

Unlike deep vein thrombosis, where large blood clots block large blood vessels. In TTP, many small clots block small blood vessels throughout the body and cause damage to vital organs like the heart, kidney, and brain. This abnormal blood clotting uses up excessive platelets, leading to a reduction in the number of platelets in the bloodstream. Platelets or thrombocytes are cells in the bloodstream that are produced in the bone marrow and help in blood clot formation.

The cause of TTP remains unknown, but some individuals may develop it after taking certain drugs like Quinine, Cyclosporine, and Mitomycin C, intestinal infection, pregnancy, or rarely as an inherited genetic factor. In the majority of individuals, TTP is an autoimmune condition where the body's immune system produces antibodies that destroy the enzyme called ADAMTS13. Decreased levels of ADAMTS1 enzyme result in inappropriate platelet clotting within the blood vessels, a decrease in the number of platelets in the blood, and damage to organs, including the heart.

The majority of individuals with TTP start showing symptoms shortly after birth. However, some individuals do not exhibit symptoms until adulthood. Symptoms may include:

• Small, flat red spots under the skin called petechiae are brought up by the leaking of blood from blood vessels.

• Red, purple, or brownish-yellow spots called purpura on the skin.

• Paleness or yellowish color of the skin.

• Tiredness.

• Fever.

• Fast heart rate.

• Shortness of breath.

• Headache.

• Speech changes.

• Confusion.

• Stroke.

• Seizure.

• Nausea.

• Vomiting.

• Diarrhea.

What Are the Cardiac Implications of Thrombotic Thrombocytopenic Purpura?

The heart emerged as the most commonly affected organ in TTP. The most frequent cardiac events in TTP patients included ischemia, myocardial infarction, CHF, arrhythmias, cardiogenic shock, and sudden cardiac death.

1. Silent Arterial Thrombosis: TPP can lead to the formation of blood clots (thrombosis) in the arteries that supply the heart without causing any noticeable symptoms. However, these blood clots can obstruct blood flow to the heart muscle, potentially leading to ischemia (lack of oxygen) and damage to the heart tissue, increasing the risk of cardiac complications.

2. Accelerated Hypertension: TTP can cause kidney dysfunction. When this occurs, the kidneys are unable to eliminate all waste and extra fluid from the body. Extra fluid in blood vessels may increase blood pressure. This elevated blood pressure puts extra strain on the heart and blood vessels, increasing the risk of complications such as heart attack, stroke, and heart failure.

3. Acute Myocardial Infarction (Heart Attack): Myocardial infarction induced by TPP is rare. However, it is a potentially life-threatening condition. In some cases, TTP can lead to the formation of blood clots in the heart vessels, which supply oxygen-rich blood to the heart muscle. If a clot completely blocks blood flow to a portion of the heart, it can result in a heart attack. Symptoms of a heart attack may include chest pain or discomfort, shortness of breath, nausea, lightheadedness, or discomfort in other areas of the upper body.

4. Atrial Fibrillation (Irregular and Rapid Heartbeat): TTP can also cause irregular and rapid heartbeat. In atrial fibrillation, the upper chambers of the heart (atria) beat irregularly instead of beating effectively enough that blood is not pumped out of the atria, which leads to blood pooling in the atria, and pooled blood is at increased risk of blood clot formation. If a blood clot dislodges and travels to the brain, it can cause a serious complication like stroke.

5. Congestive Heart Failure (CHF): TTP-induced microthrombi formation and tissue damage can impair the heart's ability to pump blood effectively, leading to congestive heart failure. CHF is a condition in which the heart becomes weakened and unable to meet the body's demand for oxygen-rich blood. Symptoms of CHF may include shortness of breath, fatigue, swelling of the legs or ankles, and difficulty exercising.

What Is the Treatment for Cardiac Complications in TTP?

The management of cardiac complications in TTP requires addressing the underlying cause of the condition while managing the cardiovascular issues that may arise.

1. Plasmapheresis, or Plasma Exchange: This procedure is used to remove the antibodies that inhibit the ADAMTS13 enzyme and also replace them with functional ADAMTS13 protein. In this process, blood is removed from the patient by a machine, blood cells are separated from plasma (the liquid portion of blood), the plasma of the patient is replaced with healthy donor plasma, and the blood is then returned back to the patient by the machine.

2. Steroids: Steroids help to inhibit the production of the anti-ADAMTS13 antibodies by the immune system.

3. Rituximab: This medication suppresses the production of the anti-ADAMTS13 antibodies. The effect of this medication lasts longer than steroids.

4. Splenectomy: Surgery for removal of spleen. The spleen is an organ located in the upper left abdomen that is used to store platelets. Removal of the spleen can increase platelet count. This aids in managing a low platelet count.

5. Antiplatelet Therapies: Antiplatelet medications, including aspirin, are frequently administered to prevent microthrombi from forming in the small blood vessels, including those supplying the heart. Aspirin lowers the chance of clot formation by inhibiting platelet aggregation.

6. Treatment of Coronary Artery Occlusion: Percutaneous coronary intervention (PCI) or thrombolysis might be an option for some cases.

7. Treatment of Heart Failure and Cardiomyopathy: Standard supportive measures include diuretics, vasodilators, potentially inotropic support, beta-blockers, calcium channel blockers, and ACE inhibitors.

8. Treatment for Heart Block and Arrhythmias: In case of heart block, a pacemaker may be necessary, and for abnormal heartbeats, antiarrhythmic medications are needed.

Conclusion

Thrombotic thrombocytopenic purpura is an uncommon but dangerous condition and has a major impact on the cardiovascular system. Timely identification of cardiac involvement in TTP is essential for better results and management.