Cherish life and stay away from blood clots

Author: Liu Dong, attending physician, Beijing Chaoyang Hospital, Capital Medical University

Reviewer: Wang Yang, Chief Physician, Beijing Chaoyang Hospital, Capital Medical University

With the change of lifestyle, more and more people are suffering from diseases such as pulmonary embolism, myocardial infarction, cerebral infarction and lower limb vascular occlusion due to the formation of "thrombosis" in the body, which blocks the lungs, heart, brain and peripheral blood vessels, seriously threatening human health. "Thrombosis" makes people change color when talking about it. Therefore, it is particularly important to strengthen the popularization and prevention of thrombosis. So, what is thrombosis, how it is formed, and how to prevent it require our scientific understanding.

1. What is a blood clot?

In layman's terms, thrombus is the abnormal coagulation of blood in blood vessels. Thrombus flows with the blood flow like a plug, and once it blocks a blood vessel, it forms an embolic disease in the corresponding part. The composition of thrombus includes deposited platelets, insoluble fibrin, accumulated red blood cells and trapped white blood cells. The above components form an insoluble mass in the blood vessel, among which platelets play a key role in coagulation. Thrombus is arterial and venous thrombosis, and the causes, composition, shape and prevention and treatment principles of the two are also different. Arterial thrombus is mostly composed of coral-like platelet trabeculae, which are grayish white, with a large number of neutrophils aggregated on the surface, affecting the blood supply of organs and tissues, and manifesting as symptoms such as limb numbness, pain, and pale skin. In severe cases, it leads to tissue and organ necrosis, which is the root cause of myocardial infarction and cerebral infarction. Venous thrombosis, commonly known as the "invisible killer", is caused by the slowing of blood flow. It is mostly composed of accumulated red blood cells and is dark red in color. Clinically, it often leads to organ and tissue congestion, resulting in symptoms such as edema and increased skin temperature. It is the root cause of deep vein thrombosis and pulmonary embolism.

Figure 1 Copyright image, no permission to reprint

2. How does a blood clot form?

Thrombosis formation includes endothelial cell damage, abnormal blood flow status, and increased blood coagulability, among which endothelial cell damage is the most important and common cause of thrombosis. Age and long-term immobilization of limbs, such as long-term bed rest and desk work, lead to limited venous return and blood stasis, which induces thrombosis. In addition, bad living habits and lifestyles can also lead to the formation of thrombosis in the body, such as obesity, long-term smoking, drinking, and high-sugar and high-fat diets, which can induce thrombosis in the body.

3. Which groups of people are susceptible to thrombotic diseases?

Generally speaking, people who lack exercise for a long time, obese people, and people with some chronic diseases are prone to thrombosis. Such as people with high blood pressure, high blood lipids, high blood sugar, and high uric acid; people with coronary heart disease, atrial fibrillation, carotid artery stenosis, etc.; the elderly, pregnant women, obese patients; people who smoke and drink for a long time; people who sit for a long time and lack exercise; people with a family history of specific diseases (such as hereditary blood diseases); people who are bedridden after trauma or surgery, and people who take specific drugs (hormones, contraceptives, and chemotherapy drugs); the above people have high-risk factors for thrombosis and are prone to thromboembolic diseases.

4. How to identify the occurrence of thrombotic diseases?

Thrombosis causes different acute ischemic symptoms due to differences in origin and location of blockage. Thrombosis blocking cerebral arteries often causes cerebral infarction, which is often manifested by sudden facial and limb weakness, speech disorders, visual field loss and other neurological deficits; thrombus blocking coronary arteries causes myocardial infarction, which is characterized by sudden precordial pain accompanied by sweating, nausea, vomiting, arrhythmia, hypotension and other symptoms; thrombus blocking pulmonary arteries causes pulmonary embolism, which is characterized by chest pain and symptoms of dyspnea such as chest tightness and shortness of breath; lower extremity venous thrombosis often manifests as sudden swelling, pain, reddening of the skin and increased temperature of the lower extremities. Understanding and recognizing the symptoms of the above common thromboembolic diseases can provide valuable time for the subsequent treatment of the disease.

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5. Diagnosis and Treatment of Thrombotic Diseases

Like most diseases, early detection, early diagnosis and early treatment are particularly important for the treatment of thrombotic diseases, which can help alleviate, reverse or even cure thromboembolic diseases.

1. Treatment of the cause

The treatment of thrombosis is first of all to treat the cause. Quit smoking and drinking, strictly control blood pressure, blood sugar and blood lipids, and actively treat other related underlying diseases. Clinically, by reducing blood viscosity, taking anticoagulants, and synchronously treating the primary disease, the risk factors for thrombosis can be completely eliminated and the occurrence of thrombosis can be prevented.

2. Antithrombotic therapy

The pathophysiological mechanisms that cause thrombotic diseases mainly include platelet activation, hypercoagulable state of blood and abnormal fibrinolysis. Therefore, the diagnosis and treatment of thrombosis only need three aspects, namely antiplatelet, anticoagulant and thrombolytic therapy.

(1) Antiplatelet therapy

Antiplatelet therapy plays a very important role in arterial thrombotic diseases, mainly by inhibiting platelet aggregation and thus inhibiting thrombosis. Existing studies have confirmed that antiplatelet drugs can effectively reduce the incidence of cardiovascular and peripheral arterial thrombosis. Commonly used first-line antiplatelet drugs include aspirin and clopidogrel.

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(2) Anticoagulant therapy

Anticoagulant therapy mainly prevents blood from clotting by inhibiting coagulation factors. Anticoagulant therapy is mainly applicable to diseases such as lower extremity venous thrombosis and acute coronary syndrome. It has no obvious clinical effect on cerebrovascular diseases such as transient ischemic attack and ischemic stroke. On the contrary, it increases the risk of gastrointestinal, skin, and gingival mucosal bleeding. Commonly used anticoagulant drugs include heparin, low molecular weight heparin, and warfarin.

(3) Thrombolytic therapy

Thrombolytic therapy can quickly dissolve fresh thrombi in blood vessels to achieve blood vessel recanalization and maintain blood supply to corresponding organs. Thrombolytic drugs, as activators of plasminogen, convert plasminogen into active plasmin by hydrolyzing peptide bonds in plasminogen molecules. Plasmin can promote the degradation of fibrin in thrombi and dissolve fibrin split products, thereby dissolving blood clots and restoring blood flow in blocked vascular cavities. Thrombolytic therapy is mainly suitable for diseases such as acute coronary thrombosis, deep vein thrombosis of the lower extremities, and acute ischemic stroke. Common intravenous thrombolytic drugs are alteplase and urokinase. When using thrombolytic drugs clinically, the drug usage specifications should be strictly followed. Thrombolytic drugs should be given intravenously quickly within the effective thrombolytic time window to carry out clinical diagnosis and treatment safely and effectively. At present, for the thrombolytic treatment of ischemic stroke, taking alteplase as an example, within 4.5 hours of the onset of ischemic stroke, the blood perfusion of the ischemic penumbra can be effectively restored within 6 hours at most, saving brain tissue function and improving the patient's clinical prognosis.

(4) Mechanical thrombectomy

Compared with drug thrombolytic therapy, mechanical thrombectomy in the target vessel appears to be more direct and effective. Taking ischemic stroke as an example, for patients with ischemic stroke caused by anterior circulation large artery occlusion, if the patient has no contraindications to mechanical thrombectomy, mechanical thrombectomy can be performed within 24 hours regardless of whether intravenous thrombolysis is performed. Mechanical thrombectomy should be started as early as possible and should not be delayed due to the evaluation of the efficacy of intravenous thrombolysis. In addition, compared with anterior circulation large vessel occlusion, the mortality and disability rates of acute basilar artery occlusion treated with drugs alone are higher. For patients with acute basilar artery occlusion with an onset of 6 to 24 hours, studies have found that patients receiving mechanical thrombectomy can still achieve good functional prognosis (mRS 0 to 3 points) at 90 days, which can significantly improve the clinical outcomes of the above patients.

6. How to prevent the formation of blood clots?

The prevention of thrombosis mainly involves maintaining a good mood, establishing a healthy lifestyle, and intervening in the risk factors of thrombosis. Specifically, it includes: ① facing life positively, stabilizing emotions, and maintaining good physical and mental health; ② balanced nutrition, low-salt and low-fat diet, quitting smoking and drinking, and drinking plenty of water; ③ proper exercise to promote blood circulation in the body, which can greatly reduce the risk of venous thrombosis; ④ actively treating primary diseases that cause thrombosis, such as atherosclerosis, hypertension, diabetes, hyperlipidemia, and hyperuricemia; ⑤ high-risk groups with risk factors such as "three highs" and atherosclerotic plaques can reasonably take antiplatelet drugs such as aspirin and clopidogrel under the guidance of a doctor; ⑥ patients who have been bedridden for a long time should be turned over frequently, elastic stockings should be worn on the lower limbs, and various coagulation indicators should be monitored regularly.

VII. Conclusion

Thrombosis is a common fatal disease, and its prevention and control requires the participation of the whole society. By adjusting the lifestyle scientifically and maintaining a healthy vascular homeostasis, we can effectively prevent and reduce the occurrence of thromboembolic diseases and protect the public health. In short, thromboembolic diseases can be completely reversed by clarifying the cause, early detection and diagnosis and treatment. Let us welcome the arrival of World Thrombosis Day with practical actions, cherish life, prevent thrombosis, and contribute to vascular health!