Cholesterol Emboli Syndrome (Cholesterol Crystal Embolism, Atheroembolism)

Epidemiology

  • Incidence
    • Following cardiac catheterization: cholesterol emboli occurs in 0.8% of cases
    • Following aorto-iliac stent placement: cholesterol emboli occurs in 1.6% of cases

Risk Factors for Atheroembolization

  • Age >50 y/o: average age is 66 y/o
  • Male Sex
  • Prior Cardiac or Vascular Procedure
  • Abdominal Aortic Aneurysm (AAA) (see Abdominal Aortic Aneurysm, [[Abdominal Aortic Aneurysm]])
  • Aortic Plaque Characteristics: usually detectable by trans-esophageal echocardiogram (TEE)
    • Larger Plaque Size: >4 mm in thickness
    • Protruding Plaques
    • Plaque Ulceration
    • Superimposed Mobile Thrombi on Plaque

(Note: anticoagulation/thrombolytic therapy are not believed to be risk factors for cholesterol emboli syndrome)


Etiology

  • Angiogram
  • Angioplasty/Stenting
  • Cardiac Catheterization (see Cardiac Catheterization, [[Cardiac Catheterization]])
  • Cardiac Surgery: due to aortic/vascular manipulation, puncture, cross-clamping, etc
    • These procedures may result in plaque disruption
  • Intra-Aortic Balloon Pump (IABP) (see Intra-Aortic Balloon Pump, [[Intra-Aortic Balloon Pump]])

Physiology

  • Atheroembolization of Aortic Atherosclerotic Plaque: cholesterol embolism is usually to smaller arteries

Risk Factors for Development of Aortic Atherosclerotic Plaque

Definitions: Types of Emboli from Aortic Atherosclerotic Plaque

  • General Comments
    • Although there is some overlap between these two entities, they generally present differently
  • Atheroembolism (Cholesterol Embolism): embolism of cholesterol crystals due to plaque rupture -> showering of circulation leads to occlusion of arterioles <200 microns in diameter
    • Clinical Manifestations
      • Cholesterol Emboli Syndrome (see below)
  • Thromboembolism: embolism of thrombus (which is usually superimposed on an atherosclerotic plaque) due to plaque rupture or other factors
    • Clinical Manifestations
      • Acute Limb Ischemia
      • Acute Mesenteric Ischemia
      • Ischemic Cerebrovascular Accident (CVA)
      • Other Organ Ischemia

Diagnosis

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Clinical Manifestations

General Comments

Factors Contributing to Variability in Clinical Manifestations

  • Location of Embolic Source
    • Aortic Arch Embolic Source: typically embolize to brain, eye, and/or upper extremity vessels
    • Descending Thoracic/Abdominal Aortic Embolic Source: typically embolize to gastrointestinal tract or lower extremity vessels (although retrograde embolization from the thoracic aorta may occur in some cases)
  • Extent of Embolization
  • Degree of Occlusion of the Affected Vessels
  • Presence of Co-Existing Peripheral Vascular Disease
    • Although cholesterol embolism usually occurs to areas with an intact arterial pulse (due to small artery involvement), pulses may be absent in patients with co-existing peripheral vascular disease

Latency of Clinical Manifestations

  • Skin manifestations may occur >30 days after the inciting event in 50% of cases

Dermatologic Manifestations

  • General Comments
    • Dermatologic manifestations are the most common clinical findings in cholesterol emboli syndrome: occur in 34% of cases
  • Blue Toe Syndrome: occurs in only 10-15% of cases

BLUE TOE

  • Cyanosis (see Cyanosis, [[Cyanosis]])
  • Gangrene (see Gangrene, [[Gangrene]]): occurs in 12% of cases
    • Usually affect the toes
  • Livedo Reticularis (see Livedo Reticularis, [[Livedo Reticularis]]): occurs in 16% of cases
    • Mottled, reticulated, or erythematous skin discoloration
    • May be red or blue
    • Blanches on pressure
    • May ulcerate in some cases
    • Usually bilateral in cholesterol emboli syndrome
    • Usually occurs in feet and lower legs (but may extend to thighs, buttocks, and back)
    • Skin biopsy: may be useful to make the diagnosis
  • Petechiae (see Petechiae, [[Petechiae]]): occur in 5% of cases
  • Purpura (see Purpura, [[Purpura]]): occur in 5% of cases
  • Scrotal/Penile Skin Loss: due to emboli to genitalia
    • Rare
    • Reported following endovascular abdominal aortic aneurysm repair
  • Skin Nodules (see Papular-Nodular Skin Lesions, [[Papular-Nodular Skin Lesions]]): occur in 3% of cases
    • May be painful and erythematous
    • Skin biopsy: may be useful to make the diagnosis
  • Skin Ulcer (see Mucocutaneous Ulcers, [[Mucocutaneous Ulcers]]): occurs in 6% of cases
    • Usually affect the toes
    • Skin biopsy: may be useful to make the diagnosis
  • Splinter Hemorrhages (see Splinter Hemorrhages, [[Splinter Hemorrhages]])

Gastrointestinal Manifestations

  • Acute Mesenteric Ischemia/Infarction (see Acute Mesenteric Ischemia, [[Acute Mesenteric Ischemia]]): emboli can occur to various sites
    • Colon: common site
    • Small Intestine: common site
    • Stomach: common site
      • Gastritis (see Gastritis, [[Gastritis]]): biopsy may aid in diagnosis of cholesterol emboli
      • Gastrointestinal Hemorrhage (see Gastrointestinal Hemorrhage, [[Gastrointestinal Hemorrhage]]): occurs in 10% of cases
    • Gallbladder
      • Acalculous Cholecystitis (see Acute Cholecystitis, [[Acute Cholecystitis]]): may be necrotizing
    • Liver
    • Pancreas
  • Weight Loss (see Weight Loss, [[Weight Loss]])

Hematologic Manifestations

Neurologic Manifestations

Ophthalmologic Manifestations

  • Hollenhorst Plaques: retinal lesions
    • The most common arterial source is the carotid artery

Renal Manifestations

  • Acute Kidney Injury (AKI) (see Acute Kidney Injury, [[Acute Kidney Injury]]): occurs in 25-50% of cases
    • May be acute or subacute (may have stuttering course, due to showers of emboli)
    • Usually seen with cholesterol emboli due to vascular procedures (but may occur in some spontaneous cholesterol emboli cases)
    • Bland urinary sediment (this may aid to distinguish it from renal infarction due to thromboembolism)
    • Recovery: usually incomplete (in contrast, contrast-induced acute tubular necrosis may show recovery after 3-5 days)

Rheumatologic/Orthopedic Manifestations

  • Myalgias (see Myalgias, [[Myalgias]])
  • Rhabdomyolysis (see Rhabdomyolysis, [[Rhabdomyolysis]]): reported with massive cholesterol emboli

Other Manifestations

  • Fever (see Fever, [[Fever]])

Treatment

  • Pain Control: important, as pain may be out of proportion to clinical findings (due to inflammatory nature of embolized cholesterol crystals)
  • Iloprost: may have benefit
  • Corticosteroids: may have benefit
  • LDL Apheresis: may have benefit
  • Prevention of Future Cholesterol Emboli
    • Statin therapy: may decrease the risk of future cholesterol embolization
    • Anticoagulation: probably not beneficial
    • Plaque removal or excision (aortic bypass, etc): may be useful if the exact source is identified (which is usually not the case)
    • Covered stents: unclear benefit
    • Revascularization: may be used in patients with flow-limiting peripheral vascular disease

References

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