Diabetic heart disease in the elderly
Introduction
Introduction to diabetic heart disease in the elderly Elderly diabetic cardiopathy (EDC) is one of the most serious complications of diabetes, and it is also a common and frequently-occurring disease in the elderly. Diabetic heart disease should include coronary heart disease caused by diabetes, diabetic cardiomyopathy and diabetic cardiopathic neuropathy. basic knowledge The proportion of sickness: 0.00352% Susceptible people: the elderly Mode of infection: non-infectious Complications: arrhythmia, cardiogenic shock, sudden death
Cause
The cause of diabetic heart disease in the elderly
(1) Causes of the disease
The pathological changes of diabetic cardiovascular disease can be divided into two types: non-specific and specific. The former refers to atherosclerosis and small arteriosclerosis, mainly involving large and medium blood vessels, including limb arteries and blood vessels such as heart and brain. The latter refers to microvascular disease and small arterial hyperplasia, limited to small blood vessels, can be seen in patients of different ages, in terms of heart size, diabetic macroangiopathy is the surface of the heart, extra-myocardial coronary artery lesions, ie coronary artery Atherosclerotic heart disease; and diabetic microangiopathy mainly refers to microvascular disease in the myocardium, that is, diabetic cardiomyopathy; in addition, neurovascular vessels may also have microvascular disease, if it occurs in the heart, it can lead to diabetic cardiac autonomy Neuropathy, diabetic heart disease is caused by metabolic disorders such as sugar and fat, coronary atherosclerosis, microvascular disease, cardiac autonomic dysfunction and abnormal myocardial metabolism, which ultimately leads to organic and functional changes in the heart.
(two) pathogenesis
Older diabetes has more insulin resistance. In recent years, insulin resistance can cause coronary atherosclerosis, microvascular disease, lipid metabolism disorder, cardiac autonomic dysfunction, hemorheological changes and hypertension.
1. Insulin stimulates its own growth and stimulates other growth factors, which can directly induce the growth of vascular smooth muscle cells and cause intimal and medial hyperplasia of the arterial wall. In addition, in vascular smooth muscle cells and fibroblasts, insulin can increase fat. Quality synthesis.
2. Insulin can increase the reabsorption of sodium and water by the distal convoluted tubules, resulting in an increase in circulating blood volume, thereby increasing blood pressure; increasing cardiac output and peripheral vasoconstriction by exciting the sympathetic nervous system; The transport increases the intracellular free calcium, so that the smooth muscle of the small arteries increases the reactivity of the vasopressor, which causes the blood pressure to rise.
3. Insulin resistance can cause lipid metabolism disorder, mainly manifested as hypertriglyceridemia, because hyperinsulinemia can promote liver synthesis of VLDL, and insulin resistance damages lipoprotein lipase, and VLDL clearance decreases. As a result, the VLDL in the peripheral cycle is further increased.
4. Hyperglycemia not only damages vascular endothelial cells, but also causes non-enzymatic saccharification and oxidation of collagen in blood vessel walls and apolipoproteins in plasma lipoproteins, which hinders normal lipid metabolism, and vascular wall glycated collagen. Adsorbs lipids in the blood, so that lipids deposit on the blood vessel wall. At the same time, hyperglycemia can lead to hyperplasia of platelets, increased fibrinogen, decreased anti-fibrinase, and even thickened endothelial cells, necrosis of the middle muscle cells and fibrosis. Increased myocardial ischemia and collateral circulation.
5. The elevated blood sugar in diabetic patients can be combined with hemoglobin to form glycosylated hemoglobin (Hb A1), which makes hemoglobin and oxygen difficult to dissociate, plus glycolysis, and then 2,3-diphosphoglycerate (2, 3-DPG) is reduced, resulting in hypoxia, which affects myocardial and vascular endothelial tissue metabolism, while gluconeogenesis is enhanced, intracellular glycogen granules are increased, intracellular glucose uptake and oxidative barrier, and ketone body utilization is limited. Intracellular free fatty acids and triacylglycerols accumulate, while fatty acid increase inhibits the activity of intracellular enzyme system, affecting the regulation of calcium ion in sarcoplasmic reticulum, and the abnormal distribution of calcium ions in cytoplasm affects contraction and relaxation of myocardial Furthermore, the enhancement of non-enzymatic glycosylation can cause glycosylated protein to accumulate in the myocardial interstitial and affect myocardial compliance. Therefore, diabetic cardiomyopathy may be caused by a disorder of glucose metabolism based on the relative lack of insulin. Caused.
Diabetic myocardial microangiopathy
Microcirculatory disorders, microangiangioma formation, and microvascular basement membrane thickening are typical changes in diabetic microangiopathy, and myocardial capillary basement membrane thickening is a characteristic change in diabetic cardiomyopathy. Other microvascular lesions include myocardial capillaries and arterioles. Irregular expansion, changes in capillary and microaneurysms, helical flexion of arterioles and venules, hyperglycemia, increased sorbitol bypass metabolism, excessive growth hormone, hemodynamics, hemorheology, coagulation With fibrinolytic activity, abnormal platelet function, red blood cell 2,3-DPG, increased glycosylated hemoglobin, tissue hypoxia, etc. are related to the occurrence and development of microvascular disease, and changes in vasoactive substances and vascular motor response, tissue hypoxia With the slow expansion of plasma volume, it can cause the general expansion of the early microvascular bed of diabetes, increased capillary static pressure and increased blood flow. These changes promote the development of diabetic microangiopathy, which can lead to heart enlargement, increased heart weight, and myocardial Degenerative stiffness, reduced compliance, reduced contractility, etc. Room dysfunction, especially in left ventricular dysfunction is more common.
Diabetic cardiac autonomic neuropathy
Glucose competes with creatinine carrier during hyperglycemia, hinders the active uptake of creatinine by nerve cells, reduces creatinine content, decreases Na+/K+-ATPase activity, and accumulates sorbitol in nerve cells, while sorbitol in nerve cells Too much can directly destroy the structure and function of the cell, so that the integrity of the cell membrane and the enzyme system are damaged, so that the nerve fiber is edema, degeneration and necrosis, and then segmental or diffuse demyelination changes, which inevitably leads to nerves. Abnormal function, at this time diabetes patients may have painless myocardial infarction, arrhythmia, orthostatic hypotension, and even sudden cardiac death.
Endothelial dysfunction and hypercoagulable state
Hyperglycemia and lipid metabolism disorders can damage vascular endothelium and expose collagen tissue, thereby activating the endogenous coagulation system, increasing vascular fibrin (Fg) levels, reducing fibrinolysis, increasing platelet adhesion and blood viscosity, resulting in blood It is hypercoagulable and eventually leads to pathological thrombosis.
Prevention
Elderly diabetic heart disease prevention
The prevention of senile diabetic heart disease is mainly to prevent coronary atherosclerosis and coronary heart disease, and diabetes with coronary artery disease is often multi-branched, so the recurrence rate of myocardial infarction is higher than non-diabetic patients, so effective control of blood sugar, Correction of lipid metabolism disorders, especially to reduce low-density lipoprotein levels, is important for improving atherosclerosis and preventing recurrence of myocardial infarction. It is now widely accepted that HMG-CoA reductase inhibitors such as pravastatin can delay arteritis. The development of sclerotherapy can stabilize plaque, improve endothelial function, reduce platelet thrombosis, promote fibrinolysis and reduce transient myocardial ischemia. Therefore, pravastatin can improve the incidence and mortality of coronary heart disease. As a secondary preventive drug, pravastatin is usually used in an amount of 10 to 40 mg/d. In addition, smoking is controlled. Long-term oral administration of aspirin 50-300 mg/d can prevent platelet aggregation and adhesion, and prevent myocardial infarction or recurrent myocardial infarction. Have a role in the health education of patients and their families, so that they know as much as possible about the knowledge of myocardial infarction In particular, to recognize that diabetic patients with myocardial infarction with atypical symptoms or even asymptomatic characteristics, constant vigilance in order to avoid delay treatment.
Complication
Elderly diabetic heart disease complications Complications, arrhythmia, cardiogenic shock, sudden death
The symptom of diabetic myocardial infarction is sudden myocardial infarction based on the symptoms of diabetes, so the condition should be biased and complicated. However, the symptoms of diabetic myocardial infarction are often lighter than non-diabetic myocardial infarction. Compared with 100 cases of diabetic myocardial infarction and 100 cases of non-diabetic myocardial infarction, it is found that mild and moderate chest pain is more common in diabetic myocardial infarction, and only 6 in non-diabetic group without chest pain. In the diabetes group, there were 46 patients, and the mortality rate in the diabetic group was higher than that in the non-diabetic group. In 1975, Solen analyzed the clinical symptoms of 285 patients with diabetic myocardial infarction. As a result, 33% had no typical angina symptoms, and 40% died within one month after the onset. In fact, it is not a mild symptom of diabetic myocardial infarction but because diabetes patients are accompanied by undetected peripheral neuritis and autonomic dysfunction. The symptoms that mask the pain often become a painless myocardial infarction, so the mortality rate Higher. This is a noteworthy clinical feature after the onset of diabetic myocardial infarction.
Symptom
Symptoms of Diabetic Heart Disease in the Elderly Common Symptoms Painful heart failure Chest tightness Arrhythmia edema
1. Elderly diabetic coronary heart disease
(1) angina pectoris: typical clinical manifestations are congenital sternal or precordial constriction pain, sometimes can be radiated to the left shoulder and elbow wrist, can also be expressed as neck, pharyngeal or abdominal pain, predisposing factors For physical activity, emotional excitement, full meal, etc., the pain lasts for a few seconds or tens of minutes, even hours, rest or sublingual nitroglycerin can be relieved, this type of angina is stable labor angina, its attack is mainly Due to one or more coronary arterial spasm, and variant angina pectoris, often in rest and lying position, the duration of seizures is long, mainly due to recurrent vasospasm on the basis of coronary artery stenosis, in non-diabetic patients Among them, typical angina pectoris can reach more than 90%, while in diabetic patients only 70%, especially in elderly diabetic patients, angina pectoris symptoms are more common or asymptomatic.
(2) Painless myocardial infarction: the incidence of acute myocardial infarction in diabetic patients is higher than that in non-diabetic patients. This has been recognized, the symptoms are often atypical, about 42% can be without angina, and the symptoms of myocardial infarction in elderly diabetic patients are not Typical and non-angina puncture is by no means accidental. It is mainly caused by slow pain response and diabetic autonomic neuropathy in the elderly. It is prone to severe cardiac insufficiency, cardiogenic shock, heart rupture, sudden death and severe arrhythmia. The main reason for the above performance is that coronary artery lesions in diabetic patients are mostly severe stenosis, which is prone to coronary thrombosis. At the same time, microvascular disease can cause collateral circulation disorder, resulting in large area myocardial infarction.
2. Elderly diabetic cardiomyopathy
Diabetic cardiomyopathy has a slow onset, which is related to the course of diabetes. It often coexists with diabetic nephropathy and retinopathy. There may be palpitation and chest tightness in the early stage. In the advanced stage, there is shortness of breath, systemic edema and hepatosplenomegaly, and even congestive breathing. Symptoms of heart failure, some patients may have orthostatic hypotension, embolism or sudden death, the main signs for heart enlargement, apical beat to the left lower shift, pulsating diffuse or lifted; auscultation heart sounds low blunt, can hear the third heart sound or The fourth heart sounds gallop, the apex or tricuspid valve area can smell the full systolic murmur of the hair sample; and can combine various types of arrhythmia.
3. Diabetic cardiac autonomic neuropathy: Diabetes can involve the vagus nerve in the early stage, so the sympathetic god is often in a state of relative excitement, so the heart rate can be increased. At rest, the heart rate is >90 beats/min, even up to 130 beats/min; Often with orthostatic hypotension, if the neuropathy is serious, the sympathetic nerve can be involved at the same time. At this time, the patient's heart rate is susceptible to various external reflexes, and the patient may be accompanied by other visceral nerve damage, such as the cheeks. Upper limbs sweating, nausea, anorexia, urinary retention, urinary incontinence, etc.; when hypoxia occurs at the same time, respiratory reflex regulation can cause sudden cardiac death, clinical manifestations of severe arrhythmia or cardiogenic shock, usually sudden onset The patient only feels short chest tightness, palpitations, can rapidly develop to severe shock, and even coma. If there are some infections at the same time, the symptoms are often obscured by the primary disease.
Examine
Examination of diabetic heart disease in the elderly
Hyperglycemia, hyperlipidemia, high fibrinogen, microalbuminuria.
X-ray, electrocardiogram, echocardiography confirmed enlargement of the heart, and echocardiography also showed segmental motion abnormalities in the wall.
Diagnosis
Diagnosis and diagnosis of diabetic heart disease in the elderly
Diagnostic criteria
1. Diagnostic criteria for elderly diabetic coronary heart disease
(1) diagnosed as diabetes.
(2) There is a history of angina pectoris, myocardial infarction or heart failure.
(3) The ST segment of the electrocardiogram showed a horizontal or down-slope reduction of 0.05mV, and the T wave was low-level, biphasic or inverted. If it changes dynamically, it supports the diagnosis of myocardial ischemia.
(4) There is a serious arrhythmia.
(5) Clinically, other organic heart diseases are excluded.
2. Diagnostic criteria for senile diabetic cardiomyopathy
(1) Those diagnosed with diabetes and whose course of disease is more than 5 years.
(2) Although there is no coronary artery disease, there is a history of heart failure.
(3) X-ray, electrocardiogram, and echocardiography all indicate that the heart is enlarged, and echocardiography can also show that the wall motion is diffusely weakened, with a large heart chamber, a small opening, and a significant decrease in left ventricular stroke volume.
(4) Cardiomyopathy and heart disease caused by other causes.
3. Diagnostic criteria for elderly diabetic cardiac autonomic neuropathy
(1) diagnosed as diabetes.
(2) 24h dynamic electrocardiogram (Holter) heart rate variability (HRV) analysis is reduced, while HRV analysis reflects the dynamic balance of sympathetic and parasympathetic nerves on cardiovascular regulation, HRV reduction indicates cardiac autonomic nerve damage, and cardiac accidents Increased risk.
(3) Resting heart rate >90 times/min at rest or fast and fixed heart rate, respiratory difference 10 times/min, breathing difference for single deep breathing, recording single deep suction and deep breathing on II lead electrocardiogram The maximum and minimum RR interval, respectively, calculate the difference in heart rate per minute between deep and deep inhalation, the normal range is >10 times / min, 10 times / min is abnormal, the respiratory difference of elderly diabetic patients is reduced, indicating that When the early autonomic nerve is involved, the vagus nerve is first involved, and the heart rate is fast and fixed.
(4) There is a history of painless myocardial infarction.
(5) The positional blood pressure difference 4kPa (30mmHg), orthostatic hypotension often occurs. Clinically, elderly diabetes with coronary heart disease, cardiomyopathy and cardiac autonomic neuropathy often exist simultaneously.
Differential diagnosis
The differential diagnosis of senile diabetic heart disease is mainly different from non-diabetic coronary heart disease, cardiomyopathy, cardiac autonomic neuropathy and hypertensive heart disease. It can be used to measure fasting blood glucose and glucose tolerance for echocardiography, 24h dynamic ECG heart rate variability. Sexual examination, combined with typical symptoms and signs, is not difficult to identify.
