What Is Microvascular Ischemia?

Causes of microvascular angina:

Microvascular angina

Microvascular angina pectoris or syndrome X refers to those who have typical symptoms of exertional angina pectoris or positive electrocardiogram exercise test, normal coronary angiography, and those with coronary spasm need to be excluded. Syndrome X is also known as microvascular angina pectoris. Its possible pathogenesis is caused by abnormalities in the structure and function of microvessels and microcirculation of coronary arteries smaller than 200 microns. In the process of understanding and diagnosing the above-mentioned concepts, we must avoid guessing, subjective reasoning, and partial generalization; we should focus on objective evidence and comprehensive evaluation; we must carry out strict diagnosis and deal with leniency. That is, don't easily put on the hat of coronary heart disease without sufficient evidence, and use appropriate preventive treatment to reduce risk. It has symptoms of exertional angina or angina-like discomfort, active plate ECG exercise test has evidence of myocardial ischemia such as ST segment depression, and coronary angiography (CAG) shows a group of clinical syndromes with normal or non-obstructive changes in coronary arteries. Likoff first reported in 1967 that Kenp called it X syndrome in 1973. Recently Cannon et al. Proposed to call it microvascular angina pectoris (CMSA). As for physical weakness, shortness of breath, and other symptoms, there are many reasons, and you should go to a hospital with conditions to see a major internal medicine. Diagnose clearly before standardizing prevention.

Affected area: chest
Related diseases: Angina Pectoris X Syndrome
Related symptoms: Biliary colic atherosclerosis nausea mitral valve prolapse pulmonary embolism calcification sensory hypertension hypertension joint swelling coronary arterial insufficient blood supply coronary artery spasm hyperventilation shortness of breath dyspnea anxiety tension menopause cough hemoptysis skin allergy fatigue pneumothorax heart esophagus spasm Weakness of numb limbs, numbness, halo, dysphagia, indigestion, pericarditis, myocardial infarction, myocardial oxygen consumption, increased palpitations, angina pectoris, heart failure, sternum pain, chest pain, anorexia

Affiliated Department: Department of Internal Medicine
Related inspections: Protein electrophoresis, tear secretion immunoglobulin A, serum immunoprotein electrophoresis, serum immunoglobulin E (IgE), serum immunoglobulin G subclass, urine prostaglandin, troponin, myoglobin, creatine kinase, cardiovascular angiography, dynamic electrocardiogram (Holter monitoring), blood analysis Selective angiography

Causes of microvascular angina:

Studies have found that 10% -20% of patients undergoing coronary angiography for angina do not have organic coronary stenosis or spasm. Some people call this kind of angina pectoris with normal coronary angiography, positive exercise test, and no other evidence of heart disease, and others suggest it is called microvascular angina pectoris. Many problems with Syndrome X are unknown. So far, the etiology and pathogenesis of Syndrome X are not completely clear. Comprehensive literature reports may be related to the following factors:

1. Decreased coronary blood flow reserve capacity

2. Endothelial dysfunction

3.Autonomic neuromodulation abnormalities

4.Estrogen

5.Other reasons, abnormal pain perception

With the popularization of CAG technology in recent years, it is found that Syndrome X is not uncommon. It is reported that this disease accounts for about 15% of cases registered in the coronary anatomy study (CASS), especially in menopausal women.

Examination and diagnosis of microvascular angina:

Cardiac X syndrome refers to the symptoms of typical angina pectoris, especially angina pectoris. The exercise stress test has ischemic ST-segment depression, but the coronary angiography before and after the ergometrine test is normal, and it can be excluded that it can cause ECG deficiency. Other heart diseases with blood changes. Syndrome X is more common in patients around 50 years of age. It is more common in women, especially in premenopausal women. The main manifestation is paroxysmal post-sternal pain. The chest pain of most patients is related to increased myocardial oxygen consumption, such as fatigue and emotional agitation. In some patients, the threshold of the physical load that induces chest pain is not constant and can occur at rest; in some patients, chest pain often lasts for a long time (30 minutes), and the effect of taking nitroglycerin is not good, and chest pain symptoms recur. After exercise, atrial pacing, and the use of vasodilators (such as pansentin, nitroglycerin, or papaverine), normal people have increased coronary blood flow, while patients with syndrome X have coronary arterial blood, although there is no stenosis in the epicardial coronary arteries. However, no corresponding increase in flow was found, indicating that the coronary blood flow reserve capacity (ie, the ratio of the maximum coronary blood flow to the basal blood flow) decreased, which is an important feature of Syndrome X.

Syndrome X-disease check

The commonly used diagnostic criteria for disease examination are: symptoms of exertional angina pectoris; positive electrocardiogram exercise test (ST segment ischemic shift down 0.1mm); or dynamic electrocardiogram detection at least one ST segment ischemic shift down 0.1mm; Coronary angiography was normal, with no spontaneous or induced (intracoronary ergometrine challenge test) coronary arterial spasm.

1. Special examinations for specialists

Special endocrine examination, special examination of stomatology, special examination of obstetrics and gynecology, cardiovascular examination, special examination of digestive system, special examination of dermatology, special examination of ophthalmology, special examination of otolaryngology, pulmonary function examination.

2.Clinical blood test

Bleeding and coagulation tests, white blood cells, red blood cells

3. Clinical Hemorheology

4. Immunological examination of infectious diseases

Gonorrhea, immunological tests for syphilis, immunological tests for severe infectious diseases, immunological tests for rickettsial infectious diseases, immunological tests for bacterial infectious diseases, immunological tests for borrelia infectious diseases.

5.Body fluids and excreta inspection

Saliva and tear test, urine test, sweat electrolyte test, serosal puncture test, synovial fluid test, sputum test, stool test, semen and prostate test, amniotic fluid test, renal function test, gastric and duodenal drainage test , Cerebrospinal fluid examination, vaginal discharge examination

6, immunological examination

Cellular immunoassay autoantibody assay serum immunoglobulin assay serum complement assay

7. Imaging inspection

B-mode ultrasound examination CT examination PET imaging X-ray examination Isotope examination Magnetic resonance examination

8.Determination of hormones

Pituitary hormone measurement, gonadal hormone measurement, gastrointestinal hormone measurement, parathyroid hormone measurement, thyroid hormone measurement, adrenal hormone measurement, pancreatic endocrine function test, other hormone measurement

9. Electrophysiology examination

10, blood biochemical examination

Amino acid, nitride, organic acid measurement Sugar measurement Lipid measurement Pigment measurement, protein measurement, blood gas analysis Blood inorganic measurement, serum vitamin measurement enzyme measurement.

11. Serological examination agglutination test precipitation, serological examination of test virus, tumor immune detection complement binding test, etc.

12, blood cell chemical staining

13.Bone marrow cytology

Differential diagnosis of microvascular angina:

Esophageal disease

(1) Reflux esophagitis: due to lax sphincter relaxation at the lower end of the esophagus, acidic gastric juice reflux, causing esophageal inflammation and spasm, manifested as burning pain behind the sternum or mid-upper abdomen, sometimes radiating to the back and suspecting angina. However, the disease often occurs when supine after a meal, which can be relieved by taking antacids.

(2) esophageal hiatal hernia: often accompanied by acid reflux, the symptoms are similar to esophagitis, often occur when bending over or supine after a full meal, gastrointestinal angiography can confirm the diagnosis.

(3) Diffuse esophageal spasm: It can also be associated with reflux esophagitis, which has various manifestations of chest pain. It is effective when taking nitroglycerin, and can be induced by ergometrine, so it is easy to suspect an angina pectoris, which is atypical angina pectoris. A common cause of sexual chest pain. According to the patient's history of acid reflux and anorexia, symptoms often occur when eating especially cold drinks or after meals, have nothing to do with exertion, and have difficulty swallowing during an episode can be distinguished from angina. Esophagoscopy and esophageal manometry can confirm the diagnosis. Clinically, angina pectoris and esophageal disease often coexist. Esophageal reflux can lower the threshold of angina pectoris. Esophageal spasm can be induced by ergometrine and relieved by nitroglycerin. Therefore, the identification of the two is often difficult. Chest pain is manifested as heartburn, and is related to changes in body position and eating. At the same time, dysphagia is a characteristic of esophageal pain; esophageal pain is more often radiated to the back than angina. Accurate diagnosis requires not only a careful history and physical examination, but sometimes also a laboratory test.

2. Lung and mediastinal diseases

(1) Pulmonary embolism: Pain occurs suddenly and appears at rest. It is seen in patients with high-risk factors of the disease (such as heart failure, venous disease, post-surgery, etc.), often accompanied by hemoptysis and shortness of breath. Its painful properties are typically described as chest tightness with or subsequent pleural inflammatory chest pain, that is, sharp pain on that side of the chest, exacerbated by breathing or coughing. X-ray chest radiography, pulmonary angiography, and lung nuclide scanning can confirm the diagnosis.

(2) Spontaneous pneumothorax and mediastinal emphysema: chest pain in both cases occurs suddenly, the former chest pain is located on the side of the chest, and the latter is located in the center of the chest, both with acute dyspnea. X-ray chest radiographs can confirm the diagnosis.

3. Biliary colic This disease often occurs suddenly. The pain is intense and often fixed. It lasts for 2 to 4 hours and then disappears on its own without any symptoms during the episode. It is usually the heaviest in the right upper quadrant, but it can also be located in the upper abdomen or in the precardiac area. This discomfort usually radiates to the scapula, and can radiate to the back along the costal margin, and occasionally to the shoulder, indicating that the diaphragm is irritated. There is often nausea and vomiting, but the relationship between pain and meals is uncertain; the disease often has a history of indigestion, flatulence, and intolerance of fatty foods, but these symptoms are also common in the general population and not very specific. Ultrasound imaging is accurate for the diagnosis of gallstones, and can understand the size of the gallbladder, the thickness of the gallbladder wall, and whether there is bile duct dilatation. Oral cholecystography failed to show gallbladder filling, suggesting no function of the gallbladder.

4. Nerve, muscle and bone causes

(1) Cervical spinal radiculitis: It can manifest as permanent pain, sometimes leading to sensory disturbances. Pain may be related to neck movements, just like the painful episodes of bursitis caused by shoulder movements. Fingers are pressurized along the back, there are skin allergies, suspicious and thoracic spinal radiculitis. Sometimes, cervical rib compression of the arm and shoulder plexus can produce pain similar to angina pectoris. During physical examination, shoulder arthritis and (or) calcification of shoulder ligament, cervical spondylosis, musculoskeletal disease resembling angina pectoris, bursitis under the acromion, and costal chondritis can also be found through activities.

(2) Thoracic rib syndrome: also known as Tietze syndrome. The pain is limited to the swelling of the costal cartilage and costal sternal joints, and there is tenderness. Tietze syndrome, a typical clinical manifestation, is uncommon, and rib chondritis causes tenderness (without swelling) at the junction of ribs and costal cartilage. During the examination, tenderness at the costal cartilage junction is a common clinical sign. Costal chondritis is usually treated with anti-doubt and anti-inflammatory drugs.

(3) Shingles: chest pain may occur in the early stage of herpes rash, and may even resemble myocardial infarction in severe cases. The diagnosis of this disease can be made based on the persistence of pain, the limitation of the skin sensory nerve fiber distribution area, the extreme sensitivity of the skin to touch, and the appearance of specific herpes.

(4) Unexplained chest wall pain and tenderness: chest pain can be caused by palpation and chest movements (such as bending down, swinging arms while walking, etc.). In contrast to angina pectoris, which can last for seconds or hours, nitroglycerin does not relieve it immediately. Generally no treatment is needed, and salicylate is occasionally needed.

5. Functional or psychic chest pain It is a manifestation of anxiety state of neurocirculation weakness. The pain can be located in the apex of the heart. It is a dull pain that lasts for several hours. It often aggravates or changes into sharp stab-like pain under the breast within 1 to 2 seconds. It usually occurs during emotional tension and fatigue, and has little to do with sports. Tenderness in the anterior region of the heart. Seizures may be accompanied by signs of palpitations, hyperventilation, numbness and tingling in the limbs, sighing, dizziness, dyspnea, general weakness and emotional instability or depression. Drugs other than analgesics do not provide relief, but can be reduced by various forms of intervention, such as rest, labor, tranquillizers, and placebo. In contrast to myocardial ischemic pain, functional pain is more likely to show different responses to different interventions. Because functional pain often occurs after hyperventilation, the latter can cause increased muscle tone and produce diffuse chest tightness. Some so-called functional chest pains may actually have a basis for organic disease. This is common in chest pain in patients with mitral valve prolapse. The nature of its chest pain varies widely from patient to patient, which can be similar to typical angina pectoris or similar to the aforementioned chest pain of neurocirculation weakness.

6. Non-coronary atherosclerotic heart and vascular disease

(1) Acute pericarditis: young onset, often with a history of viral upper respiratory infections. The onset of pain caused by its inflammation is sudden and sharper than angina pectoris. It is located to the left rather than the center of the chest, and often radiates to the neck. The pain is persistent and has nothing to do with fatigue. It can be aggravated by breathing, swallowing, and twisting the body. The pain is reduced when the patient sits up and leans forward. Auscultation has pericardial friction. The diagnosis can be confirmed with the help of an electrocardiogram.

(2) Aortic disease: when patients with high blood pressure suddenly experience continuous and severe pain, and the radiation to the back and waist indicates the possibility of aortic dissection; the continuous expansion of the thoracic aortic aneurysm can erode the spine and cause limitations and Severe drilling-like pain, especially at night; Severe aortic stenosis due to insufficient coronary blood supply can cause angina pectoris, murmurs in the aortic valve area and echocardiography can be identified.

(3) Severe right ventricular hypertension: mitral stenosis, primary pulmonary hypertension, and pulmonary heart disease can cause pain. This pain can also occur when the pulmonary arterial pressure is low, such as severe pulmonary stenosis with right ventricular hypertension. At present, this pain is believed to be due to limited cardiac output. Coronary blood flow is reduced and right ventricular oxygen consumption is increased during right systole due to right ventricular hypertension, resulting in poor myocardial perfusion. Therefore, chest discomfort can be caused by cardiac ischemia. Because the pain resolves itself and lasts several minutes, the response to nitroglycerin is difficult to evaluate. If pain is caused by activity and can be prevented by nitroglycerin, the pain is most likely due to coronary heart disease. Many patients with pulmonary hypertension have ST segment shifts on the ECG during or after exercise.

(4) Chest pain with normal coronary angiography results: Angina pectoris or similar angina pectoris syndrome with normal coronary angiography is often referred to as Syndrome X, and it needs to be distinguished from the typical ischemic heart disease caused by coronary heart disease. Its etiology is unknown, and some of the patients have real myocardial ischemia, which is manifested by increased myocardial lactate production during exercise or rapid pacing. Studies have shown that many patients with Syndrome X have microvascular and / or endothelial dysfunction, and clinically their chest pain can coexist with myocardial ischemia. However, there is no clinical evidence of myocardial ischemia in other patients. These patients often have behavioral, mental disorders, or esophageal dysfunction (expressed by the injection of hydrochloric acid into their esophagus can cause recurrence of pain), indicating chest pain Symptoms can be completely non-cardiogenic. It is now believed that chest pain in patients with normal coronary angiography can be caused by a variety of abnormal conditions: chest pain caused by ischemia due to microvascular dysfunction, called microvascular angina; chest discomfort without ischemia is hyperalgesia; chest pain Feelings are caused by arterial stretch, heart rate, heart rhythm, or changes in cardiac contractile force that stimulate the heart; sympathetic nerves dominate the sympathetic vagal imbalance which can cause syndrome X. When performing cardiac catheterization, some patients with Syndrome X are usually sensitive to the operation of intracardiac devices. Direct stimulation of the right atrium and infusion of normal saline can cause typical chest pain. Some patients may also have microvascular dysfunction and hyperalgesia. The pathological changes of the coronary arteries in patients with the so-called syndrome X are inconsistent: in some patients, the small coronary arteries have intimal thickening or atherosclerotic plaques, while some patients have completely normal coronary arteries. Patients with chest pain and normal coronary angiography are more common in women before menopause. Most of the symptoms of chest pain are atypical. Chest pain can be induced by exertion, but the threshold for triggering pain varies greatly, and sometimes the pain is very severe. The disease can affect patients' work and quality of life. Some patients may have clinical manifestations such as panic, anxiety or mental disorders. Some patients have insulin resistance and hyperinsulinemia. There were no abnormal findings in clinical examinations. Some patients may have non-specific ST-T wave abnormalities on the ECG during chest pain. Nearly 20% of patients have a positive exercise test. Exercise radionuclide myocardial imaging can find that some patients have abnormal myocardial perfusion, but it has no consistent correlation with the extent of the defect, the positive degree of exercise test, and exercise tolerance. Compared with patients with angina due to coronary atherosclerosis, the prognosis of Syndrome X is usually good, and there is no significant difference from the normal population. Patients with clinical evidence of ischemia can be treated with nitrates and beta; -blockers, but the actual treatment effect is often not satisfactory. Nitrate does not improve exercise tolerance in patients with Syndrome X, and may even reduce exercise tolerance in some patients. Calcium antagonists can reduce the frequency and severity of chest pain attacks in some patients and increase their exercise tolerance. Every effort should be made to find non-cardiac causes of chest pain during treatment. For those with gastro-esophageal reflux and esophageal dysfunction, treatment of these diseases is effective in alleviating symptoms. For those who have no evidence of ischemia and / or those who do not respond to anti-ischemic treatment, in addition to providing general supportive treatment, patiently explaining to patients the good prognosis of the disease and reassuring it is also an important part of treatment.

Prognosis and prevention of microvascular angina:

Prognosis: The prognosis of this disease is very good. The CASS registry reported a 96-year survival rate of 96% for patients with angina pectoris, normal coronary angiography, and VEF 0.50, while a 7-year survival rate for patients with CAG showing 50% of mildly abnormal stenosis was 92%. Even if these patients have a history of smoking or hypertension, exercise-induced myocardial ischemia does not increase mortality, so their prognosis is good. The long-term survival rate of patients with angina pectoris but normal CAG is very high, which is significantly higher than that of patients with coronary stenosis, and there is no difference between the survival rate of normal people of the same age. Nonetheless, long-term follow-up visits have often shown that left ventricular function remains normal, but many patients have chest pain and require medication.

Prevention: Because patients often have anxiety and fear of chest pain, patiently explaining the condition to the patient can help relieve symptoms. Moderate physical activity and physical exercise are also an effective treatment.

What Is Microvascular Ischemia?

Microvascular angina

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