Coronary atherosclerotic heart disease.
Coronary atherosclerotic heart disease is a heart disease caused by atherosclerotic lesions in the coronary arteries that narrow or block the lumen of the vessels, resulting in ischemia, hypoxia or necrosis of the myocardium, often referred to as “coronary heart disease”. However, the scope of coronary artery disease may be broader, including inflammation, embolism, etc., resulting in narrowing or occlusion of the lumen. The World Health Organization classifies coronary artery disease into five major categories: asymptomatic myocardial ischemia (occult coronary artery disease), angina pectoris, myocardial infarction, ischemic heart failure (ischemic heart disease), and sudden death. In clinical practice, they are often divided into stable coronary artery disease and acute coronary syndromes.
Common causes.
Hypertension, dyslipidemia, overweight/obesity, hyperglycemia/diabetes, poor lifestyle including smoking, irrational diet, lack of physical activity, excessive alcohol consumption, etc.
Common symptoms.
Typical chest pain, precordial discomfort, palpitations, weakness, sudden death, fever, sweating, panic, nausea, vomiting.
Risk factors and causative factors.
Risk factors for coronary artery disease include modifiable risk factors and non-modifiable risk factors. Understanding and intervening in risk factors can help in the prevention and treatment of coronary heart disease.
Modifiable risk factors include: hypertension, dyslipidemia (high total cholesterol or high LDL cholesterol, high triglycerides, low HDL cholesterol), overweight/obesity, hyperglycemia/diabetes, poor lifestyle including smoking, poor diet (high fat, high cholesterol, high calorie, etc.), lack of physical activity, excessive alcohol consumption, and psychosocial factors. Non-modifiable risk factors are: gender, age, and family history. In addition, they are related to infections, such as cytomegalovirus, Chlamydia pneumoniae, and Helicobacter pylori.
Episodes of coronary heart disease are often associated with seasonal changes, emotional stress, increased physical activity, satiety, heavy smoking, and alcohol consumption.
Clinical manifestations.
1. Symptoms.
(1) Typical chest pain: triggered by physical activity, emotional excitement, etc., sudden pain in the precordial region, mostly episodic colic or crushing pain, can also be suffocating sensation. The pain starts from the posterior sternum or precordial area and radiates upward to the left shoulder, arm, and even the little finger and ring finger. The site of chest pain dispersion may also involve the neck, jaw, teeth, abdomen, etc. Chest pain can also appear in the quiet state or at night and is caused by coronary spasm, also known as variant angina pectoris. If the nature of chest pain changes, such as the newly emerged progressive chest pain, the pain threshold gradually decreases to the point that it can also occur during slight physical activity or emotional excitement or even at rest or when sleeping. The pain gradually increases, frequency, and lengthens in duration, and cannot be relieved by removing the trigger or taking nitroglycerin, then unstable angina is often suspected.
Grading of angina pectoris: internationally, the CCSC Canadian Cardiovascular Society grading method is generally used.
Grade Ⅰ: daily activities, such as walking, climbing ladders, without angina attack.
Grade II: Daily activities are mildly limited by angina.
Class III: Daily activities are significantly limited by angina attacks.
Grade IV: Any physical activity can lead to an angina attack.
Myocardial infarction occurs with severe chest pain that lasts for a long time (often more than half an hour) and cannot be relieved by nitroglycerin, and may include nausea, vomiting, sweating, fever, and even cyanosis, blood pressure drop, shock, and heart failure.
(2) Note that some patients have atypical symptoms, manifesting only as precordial discomfort, palpitations or weakness, or predominantly gastrointestinal symptoms. Certain patients may have no pain, such as the elderly and diabetic patients.
(3) Sudden death: About 1/3 of patients with the first episode of coronary heart disease present with sudden death.
(4) Other: It may be accompanied by systemic symptoms, such as fever, sweating, panic, nausea, vomiting, etc. Patients with combined heart failure may present with 2. Signs.
Patients with angina are not special when they do not have an attack. Patients may present with diminished heart sounds and pericardial friction sounds. In cases of concomitant septal perforation and papillary muscle insufficiency, murmurs can be heard in the corresponding areas. Irregular heart rhythm is auscultated in case of arrhythmia.
Examination.
1.Electrocardiogram.
Electrocardiogram is the easiest and most commonly used method to diagnose coronary heart disease. It is the most important test, especially when the patient has an attack, and can also detect arrhythmias. Most of them are non-specific when there is no attack. The S-T segment is abnormally depressed during an angina attack, and patients with variant angina present with transient S-T segment elevation. Unstable angina mostly has significant S-T segment depression and T-wave inversion. Electrocardiographic manifestations in myocardial infarction.
① Abnormal Q waves and S-T segment elevation in the acute phase.
②Sub-acute phase with abnormal Q waves and T-wave inversion only (days to weeks after infarction).
③The chronic or old phase (3 to 6 months) has only abnormal Q waves. If S-T segment elevation persists for more than 6 months, there is a risk of complicating ventricular wall tumor. If the T wave is persistently inverted, it is called old myocardial infarction with coronary ischemia.
2.Electrocardiographic stress test.
It includes exercise stress test and drug stress test (such as pansentine, isoproterenol test, etc.). For patients who are asymptomatic in the quiet state or whose symptoms are very short and difficult to capture, myocardial ischemia can be induced by increasing the load on the heart through exercise or drugs, and the presence of myocardial ischemia can be confirmed by the change of ST-T recorded on the electrocardiogram. Exercise stress tests are most commonly used, and a positive result is considered abnormal. However, it is contraindicated in patients with suspected myocardial infarction.
3. Ambulatory electrocardiogram.
It is a method that allows continuous recording and analysis of ECG changes in active and quiet states over a long period of time. This technique was first used by Holter in 1947 to monitor electrical activity, so it is also known as Holter, and it can record changes in the ECG in the patient’s daily life, such as ST-T changes due to transient myocardial ischemia. It is non-invasive, convenient, and easily accepted by patients.
4.Nuclear myocardial imaging.
This test can be done when angina pectoris cannot be ruled out based on medical history and ECG examination, and when some patients cannot perform exercise stress test. Nuclear myocardial imaging can show the ischemic area and clarify the site and extent of ischemia. Combined with exercise stress test, the detection rate can be increased.
5. Echocardiography.
Echocardiography can examine the morphology, structure, ventricular wall motion and left ventricular function of the heart and is currently one of the most commonly used tests. It has important diagnostic value for ventricular wall tumor, intra-cardiac thrombus, heart rupture, and papillary muscle function. However, its accuracy is closely related to the experience of the ultrasonographer.
6.Hematological examination.
Blood collection is usually required to determine lipids, blood glucose and other indicators to assess the presence of risk factors for coronary heart disease. Myocardial injury markers are one of the important tools for the diagnosis and differential diagnosis of acute myocardial infarction. At present, cardiac troponin is mainly used in clinical practice.
7. Coronary CT.
Multilayer spiral CT cardiac and coronary imaging is a non-invasive, low-risk, rapid screening method that has gradually become an important means of early screening and follow-up of coronary artery disease. It is indicated for.
①Patients with atypical chest pain symptoms, where the diagnosis cannot be confirmed by ancillary tests such as ECG, exercise stress test or nuclear myocardial perfusion.
②Diagnosis of patients with low risk of coronary artery disease.
③Suspected coronary artery disease, but coronary angiography cannot be performed.
④Screening of asymptomatic patients with high-risk coronary artery disease.
⑤Follow-up after known coronary artery disease or interventional and surgical treatment.
8.Coronary angiography and intravascular imaging technology.
It can clarify the presence or absence of coronary artery stenosis, the location, degree and extent of stenosis, and can guide further treatment accordingly. Intravascular ultrasound can clarify the wall morphology and the degree of stenosis in the coronary arteries. Optical coherence tomography (OCT) is a high-resolution tomographic imaging technique that allows better visualization of the vessel lumen and vessel wall changes. Left ventriculography allows for the evaluation of cardiac function. The main indications for coronary angiography are.
① For those with severe angina despite medical treatment, clarify the arterial lesion in order to consider bypass graft surgery;
② those who have chest pain resembling angina pectoris but cannot be diagnosed.
Diagnosis.
The diagnosis of coronary artery disease relies on typical clinical symptoms, combined with ancillary tests to detect evidence of myocardial ischemia or coronary artery obstruction, and myocardial damage markers to determine whether myocardial necrosis is present. The most commonly used tests to detect myocardial ischemia include conventional electrocardiogram and electrocardiographic stress test, and nuclear myocardial imaging. Invasive tests include coronary angiography and intravascular ultrasound. However, a normal coronary angiogram does not completely negate coronary artery disease. Usually, non-invasive and convenient ancillary tests are performed first.
Treatment.
Treatment of coronary heart disease includes.
①Living habit change: quit smoking and limit alcohol, low-fat and low-salt diet, appropriate physical exercise, weight control, etc.
(ii) pharmacological treatment: antithrombotic (antiplatelet, anticoagulation), reducing myocardial oxygen consumption (beta-blockers), relieving angina pectoris (nitrates), lipid regulating and stabilizing plaque (statin lipid regulators).
(iii) Hemodynamic reconstructive therapy: this includes interventional therapy (endovascular balloon dilatation angioplasty and stenting) and surgical coronary artery bypass grafting. Drug therapy is the basis of all treatment. Interventional and surgical treatment is also followed by long-term adherence to standard drug therapy. For the same patient, medications are ideally controlled at one stage of the disease, while at another stage medications alone are often ineffective and need to be combined with interventional therapy or surgical procedures.
1.Pharmacological treatment.
The purpose is to relieve symptoms, reduce angina attacks and myocardial infarction; delay the development of coronary atherosclerotic lesions, and reduce coronary deaths. Standardized drug therapy can effectively reduce the mortality rate and the occurrence of reischemic events in patients with coronary heart disease and improve the clinical symptoms of patients. For some patients with severe vascular lesions or even complete obstruction, revascularization therapy can further reduce the mortality of patients on the basis of pharmacological treatment.
(1) Nitrate drugs: This class of drugs mainly includes: nitroglycerin, isosorbide nitrate (cardiac pain relief), isosorbide 5-mononitrate, long-acting nitroglycerin preparation (nitroglycerin ointment or rubber paste patch), etc. Nitrates are routinely used in patients with stable angina. Sublingual nitroglycerin or nitroglycerin aerosol can be used during angina attacks. For patients with acute myocardial infarction and unstable angina, the drugs should be given intravenously first, and then changed to oral or skin patches after the condition is stable and the symptoms improve, and the drugs can be stopped after the pain symptoms disappear completely. Nitrate drugs can be used continuously to develop drug resistance and decrease effectiveness, and can be taken at intervals of 8 to 12 hours to reduce drug resistance.
(2) Antithrombotic drugs: including antiplatelet and anticoagulant drugs. Antiplatelet drugs mainly include aspirin, clopidogrel (Bolivar), tirofiban, etc., which can inhibit platelet aggregation and avoid thrombosis and blockage of blood vessels. Aspirin is the drug of choice, and the maintenance amount is 75-100 mg per day. All patients with coronary artery disease without contraindications should take it for a long time. The side effect of aspirin is irritation of the gastrointestinal tract, and it should be used with caution in patients with gastrointestinal ulcers. Daily oral clopidogrel should be maintained after coronary interventions, usually for six months-1 year.
Anticoagulants include regular heparin, low molecular heparin, Juanda heparin sodium, bivalirudin, etc. They are usually used in the acute phase of unstable angina pectoris and myocardial infarction, as well as in interventional procedures.
(3) Fibrinolytic drugs: Thrombolytic drugs mainly include streptokinase, urokinase, tissue-type fibrinogen activator, etc., which can dissolve the formed thrombus at the coronary occlusion, open the blood vessel and restore blood flow, and are used in the acute myocardial infarction attack.
(4) β-blockers: β-blockers have the effect of angina pectoris and can prevent arrhythmias. In the absence of obvious contraindications, β-blockers are the first-line drugs for coronary heart disease. Commonly used drugs are: metoprolol, atenolol, bisoprolol and both alpha-blocking effect of carvedilol, armolol (Almal), etc. The dose should be to reduce the heart rate to the target range. β-blockers are contraindicated and cautioned for conditions such as asthma, chronic bronchitis and peripheral vascular disease.
(5) Calcium channel blockers: can be used in the treatment of stable angina and angina caused by coronary spasm. Commonly used drugs include: verapamil, nifedipine controlled release, amlodipine, diltiazem, etc. The use of short-acting calcium channel blockers, such as nifedipine generic tablets, is not advocated.
(6) Renin angiotensin system inhibitors: including angiotensin-converting enzyme inhibitors (ACEI), angiotensin 2 receptor antagonists (ARB), and aldosterone antagonists. These drugs should be used especially in patients with acute myocardial infarction or recent myocardial infarction combined with cardiac insufficiency. Commonly used ACEI drugs are: enalapril, benazepril, ramipril, fosinopril, etc. ARBs include: valsartan, telmisartan, irbesartan, coxsartan, etc. If there are obvious side effects of dry cough, angiotensin 2 receptor antagonists can be used instead. Care should be taken to prevent low blood pressure during drug administration.
(7) Lipid-modifying therapy: Lipid-modifying therapy is applicable to all patients with coronary artery disease. Statins are given on the basis of lifestyle changes in coronary heart disease. statins mainly lower LDL cholesterol, and the therapeutic goal is to drop to 80 mg/dl. commonly used drugs are: lovastatin, pravastatin, simvastatin, fluvastatin, atorvastatin, etc. Recent studies have shown that statins can reduce mortality and morbidity.
2. Percutaneous coronary intervention (PCI).
Percutaneous transluminal coronary angioplasty (PTCA) applies a specially designed catheter with a balloon, which is delivered to the coronary stenosis via a peripheral artery (femoral or radial artery). Filling the balloon dilates the narrowed lumen, improves blood flow, and places a stent in the dilated stenosis to prevent restenosis. It can also be combined with thrombus aspiration and rotational grinding. It is indicated for patients with stable angina pectoris, unstable angina pectoris and myocardial infarction that are poorly controlled by medications. Emergency intervention is preferred in the acute phase of myocardial infarction, and the timing is very important, the earlier the better.
3. Coronary artery bypass grafting (referred to as coronary artery bypass grafting, CABG).
Coronary artery bypass grafting relieves chest pain and local ischemia, improves patients’ quality of life, and can prolong patients’ lives by restoring myocardial blood perfusion. It is indicated for patients with severe coronary artery disease, patients who cannot receive interventional therapy or who have recurrence after treatment, and patients with angina pectoris after myocardial infarction, or with complications such as ventricular wall aneurysm, mitral valve insufficiency, or septal perforation, who should undergo coronary artery bypass grafting while treating the complications. The choice of surgery should be decided jointly by the cardiologist and cardiac surgeon and the patient.