Acute Coronary Syndrome: Coronary Vasospasm

Description

• Spontaneous episodes of chest pain due to coronary artery vasospasm in the absence of increase in myocardial oxygen demand in either normal or diseased coronary vessels
• Also known as Prinzmetal angina or variant angina, originally described in 1959
• Most common in younger patients and men
• Usually occurs in patients without cardiac risk factors or coronary artery disease
• Risk factors:
  • Smoking (up to 75% of cases)
  • Hypertension
  • Hypercholesterolemia
  • Diabetes mellitus
  • Cocaine use

Etiology

• Abnormal vasodilator function in coronary arteries typically endothelial in origin
• High prevalence of microvascular and epicardial vessel involvement
• Defined by 3 types
  • Focal: Localized, often at or near a site of stenosis of a single artery
  • Multifocal: 2 or more segments of the same artery
  • Multivessel: Involving different coronary arteries
• Unopposed α sympathetic stimulation
• Sympathetic stimulation by endogenous hormones may cause vasoconstriction.
• Conversely, also associated with increased vagal tone or withdrawal from vagal tone as proven with acetylcholine provocative testing
• Hypersensitivity of coronary arteries due to mediators of vasoconstriction
• Endothelial dysfunction possibly from genetic mutations in nitric oxide synthase
• Newer research suggests potential increase ρ-kinase activity in smooth muscle cells

Signs and Symptoms

• Chest pain:
  • Retrosternal
  • Radiates to neck, jaw, left shoulder, or arm
  • Occurs at rest
  • Occurs more frequently at night or in the morning
• Palpitations
• Presyncope or syncope
• Associated with migraine headaches and Raynaud disease in a minority of patients
• May occur during cold weather or stress
• May be prolonged in duration compared to typical angina
• May be elicited by hyperventilation
• May be elicited by exercise
• Circadian pattern, typically at night or early morning

Essential Workup

• Must include an ECG
• Use of other tests depends on history.

Diagnostic Tests and Interpretation

• ECG:
  • Transient ST-segment elevation is characteristic, is typically quite pronounced
  • Often with reciprocal changes
  • May be followed by ST depression or T-wave inversion
  • May have associated dysrhythmia during coronary spasm
  • Heart block with right coronary artery spasm
  • Ventricular tachycardia with LAD spasm
  • In rare cases can present with sudden death during prolonged vasospasm period

• Troponin
• CK/CKMB fraction
• Toxicology screen:
  • Helpful if cocaine is suspected as etiology of chest pain

• CXR:
  • May be helpful to rule out other etiologies such as pneumonia, pneumothorax, or aortic dissection
• Noninvasive coronary imaging (nuclear perfusion, coronary CTA, coronary MR):
  • Typically only helpful when combined with provocative testing

• Exercise stress testing:
  • Usually not helpful, but can help define those with true ischemic disease
• Noninvasive provocative hyperventilation
  • Highly specific, moderately sensitive, tends to favor those with increased disease activity
  • Paired with either EKG or EKG plus perfusion imaging
• Holter monitor:
  • Can be helpful in silent cases or dysrhythmia
• Coronary angiography:
  • Mild atherosclerosis is often the norm
  • Provocative test with acetylcholine is the gold standard

Differential Diagnosis

• Angina pectoris
• Anxiety and panic disorders
• Aortic dissection
• Cocaine chest pain
• Esophageal rupture
• Esophageal spasm
• Esophagitis
• GERD
• Mitral valve prolapse
• Musculoskeletal chest pain
• MI
• Peptic ulcer disease
• Pericarditis
• Pneumothorax
• Pulmonary embolism
• Takotsubo cardiomyopathy

Pre Hospital

Treat as any other acute coronary syndrome.

Initial Stabilization/Therapy

• IV access
• Oxygen
• Cardiac monitoring
• Vital signs and oxygen saturation

Ed Treatment/Procedures

• All patients with chest pain in which cardiac ischemia is a consideration should receive an aspirin upon arrival to the ED:
  • Paradoxically may increase severity of Prinzmetal angina due to inhibition of biosynthesis of naturally occurring coronary vasodilator—prostacyclin
• Nitroglycerin should still be administered and usually will help relieve both ischemic and vasospastic chest pain.
• A trial of calcium-channel blockers is indicated if clinical history is consistent with coronary vasospasm.
• Heparin and β-blockers are not helpful in true coronary vasospasm:
  • β-blockers may be detrimental due to unopposed α-mediated vasoconstriction and should be avoided in suspected cocaine chest pain.

Medication

• Aspirin: 325 mg PO
• Diltiazem: 30–60 mg PO (immediate release)
• Nitroglycerin, either:
  • 0.4 mg sublingual
  • 10–20 μg/min IV USE NON-PVC tubing, titrating to effect
  • 1–2 in of nitro paste
• Verapamil: 40–80 mg PO (immediate release)

• >40% of patients will have recurrence of vasospastic angina despite calcium-channel blocker therapy

• α-blocking agents
• Statin therapy
• Percutaneous intervention with stenting of fixed lesions in area of vasospasm controversial; can lead to spasm in other areas of coronary tree
• Pacemaker placement for patients with recurrent syncope or AV nodal block from vasospastic angina

Disposition

• New-onset chest pain
• Rule-in with positive biochemical markers or provocative testing
• Rule-in with positive biochemical markers or stress testing
• Many patients previously admitted to the hospital can now be effectively evaluated in a chest pain observation unit or clinical decision unit

• Stable (chronic chest pain)
• Negative ischemic workup

Follow-Up Recommendations

Cardiology follow up within 7 days of ED evaluation

See Also

• ACS Unstable Angina
• ACS Myocardial Infarction

ICD-9

• 411.1 Intermediate coronary syndrome
• 413.1 Prinzmetal angina

ICD-10

• Angina pectoris with documented spasm
• Acute ischemic heart disease, unspecified

SNOMED

• 87343002 Prinzmetal angina (disorder)
• 394659003 Acute coronary syndrome (disorder)