Metabolic Syndrome and the Heart

KEY FEATURES

ESSENTIALS OF DIAGNOSIS

• Truncal obesity

• Insulin resistance with fasting hyperglycemia

• Elevated triglycerides and reduced high-density lipoprotein (HDL) cholesterol

• Hypertension

• Hyperuricemia

• Premature coronary and peripheral artery disease

GENERAL CONSIDERATIONS

• The metabolic syndrome consists of the constellation of:

  • – Hypertension

  • – Dyslipidemia

  • – Insulin resistance

  • – Obesity

• Other associated abnormalities include:

  • – Microalbuminuria

  • – High uric acid blood levels

  • – Augmented blood clotting

  • – Premature atherosclerosis

• Generally, 40% of people with hypertension also have hypercholesterolemia

CLINICAL PRESENTATION

SYMPTOMS AND SIGNS

• Angina or acute coronary syndrome

• Symptoms of congestive heart failure

• Intermittent claudication

PHYSICAL EXAM FINDINGS

• S₄

• Signs of heart failure

• Body mass index > 30 kg/m²

• Reduced peripheral pulses

DIFFERENTIAL DIAGNOSIS

• Other causes of premature coronary artery disease

• Other causes of hypertension

• Other causes of obesity

DIAGNOSTIC EVALUATION

LABORATORY TESTS

• Fasting glucose, hemoglobin A_1C, lipids, uric acid

• Urine albumin and protein

ELECTROCARDIOGRAPHY

• May show evidence of left ventricular hypertrophy or myocardial infarction

IMAGING STUDIES

• Echocardiography frequently shows:

  • – Impaired diastolic function of the left ventricle

  • – Left heart chamber enlargement

  • – Left ventricular systolic dysfunction

DIAGNOSTIC PROCEDURES

• CT calcium score and coronary angiography

• Invasive coronary angiography in selected patients

• Ankle–brachial index

• Peripheral angiography in selected patients

TREATMENT

CARDIOLOGY REFERRAL

• Suspected cardiac disease

• Difficult to control hypertension

• Suspected peripheral arterial disease

HOSPITALIZATION CRITERIA

• Acute coronary syndromes

• Heart failure

• Critical limb ischemia

MEDICATIONS

• Oral hypoglycemic agents, insulin sensitizers, and insulin to bring the hemoglobin A_1C to < 7%

• Pharmacologic treatment of hypertension with angiotensin-converting enzyme inhibitors or angiotensin receptor blockers to < 130/80 mm Hg. If further blood pressure control is required, diuretics and calcium blockers are preferred to beta blockers.

• Pharmacologic lipid-lowering therapy to lower low-density lipoprotein (LDL) cholesterol < 100 mg/dL with statins

• Pharmacologic therapy to reduce triglycerides and increase HDL with fibrates, nicotinic acid, or omega-3 fatty acids

THERAPEUTIC PROCEDURES

• Coronary revascularization may be necessary

• Peripheral revascularization may be necessary

SURGERY

• Coronary bypass surgery may be indicated

• Peripheral artery bypass may be indicated

MONITORING

• ECG monitoring in hospital as appropriate

• Monitor metabolic parameters during specific therapy

DIET AND ACTIVITY

• Low-fat, low-sodium, low-calorie diet or DASH diet

• Activity ...