Cardiac Syndrome X (Microvascular Angina Pectoris)

KEY FEATURES

ESSENTIALS OF DIAGNOSIS

• Angina pectoris

• Positive stress test for myocardial ischemia, especially exercise ECG or stress myocardial perfusion abnormalities

• Normal or near-normal epicardial coronary arteries

• Majority are women

• No evidence of coronary spasm on ambulatory ECG monitoring or coronary angiography

GENERAL CONSIDERATIONS

• This syndrome is different from metabolic syndrome X

• Microvascular endothelial dysfunction is believed to be the cause, but its etiology is unclear

• Has been reported in 3–20% of patients undergoing coronary angiography for angina symptoms depending on the exclusion criteria employed.

• Most studies exclude patients with:

  • – Valvular heart disease

  • – Diabetes mellitus

  • – Left ventricular hypertrophy

  • – Systemic hypertension

  • – Cardiomyopathy

  • – Systolic heart failure

  • – Left bundle branch block

CLINICAL PRESENTATION

SYMPTOMS AND SIGNS

• Atypical chest pain in many patients

• Classic effort angina in a majority

• Chest pain possibly severe and disabling

• Angina may occur with exertion or at rest but seldom at night

• Poor or worsening response to nitrates

PHYSICAL EXAM FINDINGS

• Positive findings uncommon

• Evidence of autonomic dysfunction in an occasional patient

DIFFERENTIAL DIAGNOSIS

• Variant angina pectoris

• Missed coronary artery lesions because of inadequate angiography

• Other causes of chest pain with a false-positive stress test, such as esophageal dysmotility

• Neuropsychiatric disorder

DIAGNOSTIC EVALUATION

LABORATORY TESTS

• CBC to exclude anemia as an etiology for chest pain

• Metabolic panel

• Lipid panel

• Fasting glucose, hemoglobin A1c

ELECTROCARDIOGRAPHY

• ECG may be abnormal

• Holter monitoring may show ST depression even if stress test was negative

IMAGING STUDIES

• Stress echocardiogram and nuclear stress tests may be abnormal

DIAGNOSTIC PROCEDURES

• Coronary angiogram to exclude epicardial lesions or vasospasm

TREATMENT

CARDIOLOGY REFERRAL

• Patients with angina are referred to cardiologists on most occasions

HOSPITALIZATION CRITERIA

• Persistent severe pain

• Accelerating symptoms

MEDICATIONS

• Reassurance; prognosis is good

• Calcium channel blockers

• Statins even if lipids normal

• Vasodilatory beta blockers for selected patients

• Ranolazine for selected patients

• Omega-3 fatty acids in some patients

• Spinal cord stimulation in selected cases

• Estrogen in some cases

MONITORING

• Reevaluation during exacerbation

DIET AND ACTIVITY

• Cardiac low-fat diet

• Physical exercise or cardiac rehabilitation

ONGOING MANAGEMENT

HOSPITAL DISCHARGE CRITERIA

• Control of symptoms

• After angiogram findings are known, patients may be managed as outpatients