Diabetes and Coronary Heart Disease
Coronary heart disease (CHD) is a major macrovascular comorbidity of diabetes mellitus, and it has been reported that up to 72.3% of diabetes mellitus is complicated by CHD, and about 50% of type 2 diabetes mellitus patients have CHD at the time of diagnosis. The third report of the National Adult Cholesterol Education Program (ATP III) in 2001 clearly stated that “diabetes is a risk factor for coronary heart disease”. In 2001, the Chinese Medical Association’s Diabetes Society organized a survey on the prevalence of complications among diabetic patients hospitalized in 10 hospitals in Beijing, Tianjin, Shanghai, and Chongqing, and the number of combined cardiovascular complications was 93%, including 41.8% for hypertension, 25.1% for CHD, and 17.3% for cerebrovascular disease. This is two to four times the rate of non-diabetic patients. Therefore, in a sense, the main goal of diabetes prevention and treatment is to prevent and delay the occurrence of CHD as much as possible, so as to reduce the death rate of CHD in diabetes.
Coronary heart disease (CHD) is a disease that causes myocardial ischemia and necrosis due to the rupture and bleeding of atherosclerotic plaques and/or plaque rupture and thrombosis. The common clinical types of coronary heart disease are.
1) chronic stable angina pectoris (SAP);
(2) acute coronary syndrome (ACS), including unstable angina (UA), non-ST-segment elevation myocardial infarction (NSTEMI) (3) ST-segment elevation myocardial infarction
(3) ST-segment elevation myocardial infarction (ST-segment elevation myocardial infarction, STEMI) or acute myocardial infarction (AMI). The clinical manifestations, treatment and prognosis are different from those of non-diabetic patients because of the more serious pathological changes when diabetes is complicated by coronary heart disease.
(A) Chronic stable angina pectoris
Angina pectoris is a syndrome characterized by discomfort in the chest, neck, shoulders or hips. Typical manifestations are: 1) chest discomfort is often cramping, tightness, pressure or heaviness, not a cutting or stabbing pain; 2) location behind the sternum but may radiate to the neck, upper abdomen or left shoulder and arm; 3) duration of a few minutes; 4) exertion or emotional agitation is often the trigger; 5) rest or sublingual nitroglycerin tablets are often relieved within 30 seconds to a few minutes. Angina pectoris is often atypical in diabetic patients.
Angina usually occurs in patients with large coronary artery involvement in ≥1 branch of the coronary artery, and there are often ischemic changes in the corresponding leads of the electrocardiogram during the attack. However, angina can also occur in other heart diseases such as valvular disease, hypertrophic heart disease, and myocardial ischemia associated with coronary artery spasm or vascular endothelial dysfunction. Sometimes non-cardiovascular disorders such as esophageal, chest wall or pulmonary disorders can also resemble angina pectoris. It should be differentiated in the diagnosis of angina pectoris in coronary atherosclerotic heart disease.
Treatment objectives.
1) Prevention of myocardial infarction and sudden death.
2) To reduce symptomatic myocardial ischemic attacks and improve the quality of life.
Treatment points.
1) Take aspirin 75-300mg/d when there is no contraindication, the effect of reducing cardiac mortality is greater in diabetic patients than in non-diabetic patients β-blockers can be applied with or without myocardial infarction when there is no contraindication, the survival and benefit after infarction is greater in diabetic patients than in non-diabetic patients. However, it should be noted that β-blockers may mask hypoglycemic response and impair glucose tolerance.
(2) Angiotensin-converting enzyme inhibitors (ACEI) are appropriate in diabetic patients with left ventricular systolic insufficiency.
3) Patients with confirmed or proposed coronary artery disease and LDL-C >120 mg/dl (3.1 mmol/L) may be treated with lipid-regulating drugs such as hydroxymethylglutaryl coenzyme A (HMG-CoA) reductase inhibitors to reduce LDL-C to <100 mg/dl (2.6 mmol/L).
4) Sublingual nitroglycerin tablets or use nitroglycerin spray to relieve angina. If there is no old myocardial infarction and no contraindication, β-blockers can be used to relieve angina pectoris.
(5) If there are contraindications to beta-blockers, long-acting dihydropyridine calcium channel blockers or long-acting nitrate preparations can be used.
(6) Coronary angiography in patients with diabetes mellitus combined with coronary artery disease often shows diffuse coronary artery lesions, and coronary artery bypass grafting (CABG) is recommended if two lesions include proximal lesions of the anterior descending branch or three lesions. If the angina is mild and the left ventricular function is normal in single-branch lesions, medication or percutaneous coronary angioplasty (PTCA) or stent implantation can be performed.
(7) Intensive control of fasting glucose, postprandial glucose and glycated hemoglobin (HbA1c) must reach the target value.
(II) Acute coronary syndrome
Nomenclature of acute coronary syndrome: The ECG of patients with ischemic chest pain may show ST-segment elevation or no ST-segment elevation. Most patients with ST-segment elevation eventually develop Q-wave myocardial infarction (QMI), and a minority develop acute non-Q-wave myocardial infarction (NQMI). Patients without ST-segment elevation develop unstable angina (UA) or NQMI. the distinction between the latter two ultimately depends on whether cardiac markers [troponin T or I (TnT or TnI), or creatine kinase (CK-MB)] can be detected in the blood. Acute coronary syndrome is a group of clinical symptoms caused by acute myocardial ischemia.
The category of acute coronary syndromes includes unstable angina, non-Q-wave myocardial infarction or Q-wave myocardial infarction. This section only discusses unstable angina and non-Q-wave myocardial infarction, while Q-wave myocardial infarction is also described in the guidelines for diagnosis and treatment of acute myocardial infarction.
Acute coronary syndrome in diabetic patients has a higher mortality rate and a more serious prognosis than in non-diabetic patients, regardless of short-term and long-term follow-up.
Key points in the treatment of acute coronary syndromes.
1) Early risk stratification. All patients with acute myocardial ischemia and precordial discomfort in coronary artery disease should undergo early risk stratification assessment. Based on angina symptoms, signs, 12-lead ECG and biochemical markers of myocardial injury, such as TnT, TnI, CK-MB or myoglobin, high-sensitivity C-reactive protein (hsCRP) and other inflammatory indicators, patients suspected of developing acute coronary syndrome are assessed for their risk of death and non-fatal cardiac ischemic events, which can be classified as low-risk, medium-risk and high-risk. Patients with rapidly increasing angina, pre-existing myocardial infarction and elevated TnT and significantly elevated hsCRP often suggest a poor prognosis. Patients with diabetes mellitus often have insignificant or even asymptomatic symptoms of chest pain, but serious pathological changes, all belong to intermediate or high-risk patients.
(2) Patients with definite acute coronary syndrome with progressive chest discomfort, positive markers of myocardial injury and new T-wave inversion, hemodynamic abnormalities or positive ECG stress test need emergency hospitalization.
①Treatment of acute myocardial ischemia: sublingual or oral nitroglycerin inhalation followed by intravenous drip to rapidly relieve ischemia and related symptoms; oxygen in case of cyanosis or dyspnea; β-blocker can be given intravenously and then orally if progressive chest discomfort is not contraindicated; ACEI is recommended in case of diabetes mellitus and left ventricular systolic dysfunction.
Platelets and anticoagulation: start antiplatelet therapy quickly, preferably with aspirin chewed immediately and applied continuously; clopidogrel is available for those who are allergic to aspirin or cannot tolerate gastrointestinal disorders; antiplatelet therapy in diabetic patients reduces mortality more than in non-diabetic patients; anticoagulants are available as normal heparin or low molecular heparin (LMWH), LMWH is better than normal heparin; platelet glycoprotein receptor antagonists (GpIIb/IIIa receptor antagonists) have similar effects to those in non-diabetic patients.
(iii) Selection of percutaneous coronary angioplasty (PTCA) and coronary artery bypass grafting (CABG): diabetic patients are mostly at high risk. CABG is preferred. PTCA is also optional if there is no obvious proximal lesion of the anterior descending branch and there is a large amount of surviving myocardium in a 2-branch lesion.
④ Post-discharge management: Unstable angina and non-ST-segment elevation myocardial infarction often progresses to myocardial infarction after 2 to 3 months in the acute phase or there is a greater risk of recurrent myocardial infarction or death. The clinical course of most patients 1 to 3 months after the acute phase is similar to that of chronic stable angina pectoris. Patients should be educated, rehabilitated, and adhered to medication and follow-up. Strict control of diabetes mellitus should also be emphasized.
(C) ST-segment elevation myocardial infarction (STEMI or QMI)
See our guidelines for the diagnosis and treatment of acute myocardial infarction. It should also be emphasized that diabetic patients benefit more than non-diabetic patients when there is an indication for thrombolysis in acute myocardial infarction. The success rate of first PTCA in diabetic patients is similar to that of non-diabetic patients, but the restenosis rate and long-term prognosis are worse than those of non-diabetic patients. 2 or 3 coronary artery lesions are more likely to be treated with CABG. aspirin, β-blockers, and ACEI are more beneficial than those of non-diabetic patients.
Fourth, diabetes combined with cerebrovascular disease
Cerebrovascular disease refers to the brain lesions caused by various cerebrovascular diseases. According to the pathological evolution of cerebrovascular diseases, they are classified into hemorrhagic cerebrovascular diseases, such as cerebral hemorrhage and subarachnoid hemorrhage, and ischemic cerebrovascular diseases, such as transient ischemic attack and cerebral infarction (including embolic cerebral infarction, thrombotic cerebral infarction and lacunar cerebral infarction). Stroke refers to a group of cerebrovascular diseases with sudden onset, focal or diffuse brain dysfunction as a common feature.
The prevalence of cerebrovascular disease in diabetes mellitus is higher than that in non-diabetic population, where the prevalence of cerebral hemorrhage is lower than that in non-diabetic population, while the prevalence of cerebral infarction is four times higher than that in non-diabetic population. According to a survey conducted by the Chinese Medical Association Diabetes Branch in 2001 on the complications of diabetic patients hospitalized in 30 provinces and cities in China in the past 10 years, the number of diabetic patients with combined cerebrovascular disease was as high as 12.2%. A large number of case-control and prospective epidemiological studies have shown that diabetes mellitus is an independent risk factor for ischemic stroke. Compared with the non-diabetic population, patients with diabetes mellitus have higher mortality, disability and recurrence rates and slower recovery from stroke. Diabetic cerebrovascular disease severely impairs patients’ poor quality of life, significantly increases medical expenses, and is a great burden to individuals, families and society.
(A) Clinical manifestations, diagnosis and differential diagnosis
1, cerebral hemorrhagic disorders
Most often occurs after strenuous exercise, alcohol abuse, emotional excitement. The onset is sudden and acute. There are often headaches, symptoms of central and peripheral nerve damage, and a high incidence of impaired consciousness. It may gradually stabilize within 2-3 days after the onset, but the prognosis is poor if it worsens progressively.
2. Ischemic cerebrovascular disorders
Because of high blood sugar and blood concentration in the early morning, and blood pressure is often high in the morning, ischemic cerebrovascular disease mostly occurs between 4:00 and 9:00 am.
The initial lesions are more limited, so the symptoms are mild or there are no obvious conscious symptoms. The first symptoms are mostly weakness of one limb on waking up, limitation of voluntary activity, and decreased muscle strength. There may be significant relief in a relatively short period of time.
Since the intracranial pressure is mostly not significantly elevated, the headache is mostly not severe or not obvious.
Embolic cerebral infarction is the same as cerebral thrombotic cerebral infarction in terms of pathogenesis and influencing factors, and its onset is mostly seen in older diabetic patients who are quiet and less active for a long time, especially those who are bedridden for a long time, and the onset is sudden.
3.Diagnosis and differential diagnosis
Because the treatment of cerebral hemorrhagic disorders and ischemic cerebrovascular disorders is significantly different, so the differential diagnosis is very important. In addition to the typical clinical symptoms, the diagnosis mainly relies on the impact study (such as CT, MRI scan, etc.). The nature, location and extent of the lesion can often be clarified by scanning 6 hours after the onset of the disease and can be reviewed 2 to 3 days later to see if the disease is stable or progressing.
(ii) Treatment
(1) Pay attention to monitoring respiratory, circulatory and other vital signs in critically ill patients, keeping the airway open, preventing hypoxemia, actively treating the cause, controlling elevated body temperature, preventing and controlling infection, and paying attention to nutritional support.
2）Timely control blood pressure, except for special cases, should keep blood pressure within the normal range, also should pay attention to prevent blood theft in the process of lowering blood pressure.
3) Gradually and slowly lower blood sugar with insulin. If blood glucose decreases too quickly, there is a risk of inducing increased intracranial pressure and hypoglycemia.
4）Regulate the blood sodium to keep it at the low limit of the normal range to prevent the rise of blood pressure and heart failure induced by the increase of intracranial pressure and blood volume.
(5) Pay attention to timely detection and management of acute stress insufficiency.
(6) Give adequate amount of L-carnitine, calcium p-phenobenzene sulfonate and/or thrombolytic therapy within 3-6 hours of the onset of cerebral infarction. After intracranial hemorrhage is clearly excluded, recombinant tissue-type fibrinogen activator (e.g., rt-PA) can be used.
(7) Nerve growth factor, neuromodulin can be used when available.
8) Prompt surgical treatment should be considered in case of large brain hemorrhage or compression of important parts.
9）Early rehabilitation. Any treatment for old stroke after more than 1 to 3 months after onset is difficult to achieve significant effect.
(10) Timely detection and management of elevated intracranial pressure.
(C) Prevention
(1) Blood glucose, blood pressure, lipids, blood rheology, cerebrovascular resistance, insulin sensitivity and endothelial factors must be kept within the normal range as much as possible.
(2) Strictly scientific selection of drugs, not all drugs that can lower blood sugar, blood pressure and blood lipids are good drugs. For example, long-acting converting enzyme inhibitors that can reduce blood pressure and vascular resistance and lower the peak-to-valley ratio of blood pressure can reduce the risk of vascular accidents by more than 65%, and they are also effective in small doses for patients with low blood pressure and should be the drug of choice. Some statins not only lower cholesterol, but also improve blood flow. And some drugs that reduce renal blood flow and/or affect the myocardium such as diazepam, glibenclamide, thiazide diuretics, and biguanides that promote lactate formation should be used with caution.
3) Antiplatelet therapy: The use of aspirin is effective in reducing the recurrence of stroke and transient ischemic attack and can be used as a secondary prevention measure. Aspirin may also be used as primary prevention in diabetic patients at risk for macrovascular disease. Patients who are not suitable for aspirin can take clopidogrel as an alternative.
4) Lifestyle modification: reasonable diet, good exercise habits, maintenance of ideal body weight, prohibition of heavy alcohol consumption and smoking ban. These measures have a positive effect on the prevention of diabetic cerebrovascular disease.