Metabolic syndrome and carotid artery stenosis: Cluster assessment of multiple risk factors and medical treatment

Metabolic syndrome. Metabolic syndrome is a recently recognized and widely recognized syndrome. Its characteristic factors include obesity/abdominal obesity, dyslipidemia, high blood pressure, and insulin resistance (with or without impaired glucose tolerance), which are the main pathological basis of insulin resistance metabolic syndrome, hence it is also known as insulin resistance syndrome. Because this syndrome involves multiple risk factors for cardiovascular and cerebrovascular diseases, the 3rd Implementation Guidelines of the National Cholesterol Education Program Expert Group (ATP III) in the United States listed controlling metabolic syndrome as a secondary goal of treatment to reduce the risk of cardiovascular and cerebrovascular diseases. my country has also proposed metabolic syndrome criteria based on the Chinese population; a diagnosis is established if three out of five indicators are abnormal.

Recommendations:

1. Control its causes (e.g., unhealthy diet, insufficient physical activity).

2. Treat all coexisting risk factors to reduce the risk of cardiovascular and cerebrovascular diseases.

3. Recommended treatment goals are: weight loss of more than 5%; blood pressure <125/75 mmHg; LDL-C <2.6 mmol/L (100 mg/dL), TG <1.7 mmol/L (150 mg/dL), HDL-C >1.04 mmol/L (40 mg/dL) (male) or >1.3 mmol/L (50 mg/dL) (female); fasting blood glucose <6.1 mmol/L (110 mg/dL), 2-hour postprandial blood glucose <7.8 mmol/L (140 mg/dL), and HbA1c <6.5%.

Carotid artery stenosis. The most common causes are localized hemodynamic impairment and atherosclerosis. 7%–10% of men and 5%–7% of women over 65 years of age have carotid artery stenosis greater than 50%. Carotid artery stenosis is closely related to ischemic cerebral diseases, especially stroke, with approximately 30% of ischemic strokes caused by extracranial carotid artery stenosis. The North American Symptomatic Carotid Artery Stenosis Endarterectomy Study showed that the annual stroke incidence rate was 3.2% (after more than 5 years of observation) in individuals with stenosis of 60%–99%. On the same side as the carotid artery stenosis, the annual stroke probability is related to the degree of stenosis: 3.0% in patients with 60%–74% stenosis; rising to 3.7% in patients with 75%–94% stenosis; decreasing to 2.9% in patients with 95%–99% stenosis; and only 1.9% in patients with complete carotid artery occlusion.

Whether carotid artery stenosis is symptomatic is closely related to clinical prognosis; the 2-year stroke incidence rate in patients with symptomatic carotid artery stenosis >70% can be as high as 26%. Routine physical examination should include checking for carotid vascular murmurs, which can be heard in the carotid region in some patients. Neurological examination may reveal signs of ischemic cerebrovascular disease, and occasionally mental and intellectual abnormalities. Fundus examination may reveal microemboli, mostly cholesterol crystals, at the bifurcation of retinal arteries. Patients with concurrent subclavian artery or lower extremity arteriosclerosis obliterans may also exhibit corresponding signs. Suspected cases should undergo carotid ultrasound examination, which is non-invasive, safe, simple, and inexpensive.

1. Medical Treatment. It is now believed that aggressive comprehensive medical treatment for carotid artery stenosis is no less effective than surgical treatment.

(1) Antiplatelet Aggregation. Antiplatelet drugs should be given to patients without contraindications, regardless of whether surgery is performed. Commonly used antiplatelet drugs include aspirin and clopidogrel, both of which can be used as initial treatment. Compared to aspirin alone, aspirin combined with clopidogrel is more effective in inhibiting platelet aggregation, but it increases the risk of bleeding. The choice should be made based on the patient's economic situation and tolerance. Recommended dosage and administration: Aspirin 75-325 mg/day. Enteric-coated aspirin can reduce the incidence of gastric and duodenal ulcers. Sustained-release aspirin 100 mg/day orally increases patient compliance. Clopidogrel 75 mg/day. A loading dose of clopidogrel can be given during emergency surgery.

(2) Statins. Statins not only lower blood lipid levels, but more importantly, they restore endothelial function and stabilize plaques. Statins should be given to patients without contraindications. Patients without lipid metabolism disorders can also benefit and should be given them routinely. Commonly used drugs: Atorfastatin: initial dose 10-20 mg/day, dose range: 10-80 mg/day; Simvastatin: initial dose 10-40 mg/day, dose range: 5-80 mg/day; Pravastatin: initial dose 40 mg/day, dose range: 10-80 mg/day.

(3) Control of risk factors. Hypertension: Antihypertensive treatment is recommended for patients with elevated blood pressure. A reduction of 10/5 mmHg in blood pressure is beneficial. It is important to note that individualized blood pressure targets should be set during antihypertensive treatment: for unilateral carotid artery stenosis >70%, systolic blood pressure should not be lower than 130 mmHg; for bilateral carotid artery stenosis >70%, systolic blood pressure should not be lower than 150 mmHg. Otherwise, the risk of cerebral ischemia increases, and close monitoring for signs of insufficient cerebral blood supply is necessary. Diabetes: Controlling blood glucose to near-normal levels reduces microvascular complications. During treatment, glycated hemoglobin (HA1c) should be <7%.

Hyperlipidemia: Controlling blood lipids through comprehensive prevention and treatment includes:

1) Lifestyle modifications;

2) Dietary changes;

3) Drug therapy. Statins are recommended, with LDL-C being the primary treatment target.