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)

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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]])

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Physiology

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

Risk Factors for Development of Aortic Atherosclerotic Plaque

• Age
• Coronary Artery Disease (CAD) (see Coronary Artery Disease, [[Coronary Artery Disease]])
• Diabetes Mellitus (DM) (see Diabetes Mellitus, [[Diabetes Mellitus]])
• Hypertension (see Hypertension, [[Hypertension]])
• Hyperlipidemia (see Hyperlipidemia, [[Hyperlipidemia]])
• Obesity
• Tobacco Abuse (see Tobacco, [[Tobacco]])

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

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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

• 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
    • Diarrhea (see Diarrhea, [[Diarrhea]])
    • Gastrointestinal Hemorrhage (see Gastrointestinal Hemorrhage, [[Gastrointestinal Hemorrhage]]): occurs in 10% of cases
  • Small Intestine: common site
    • Gastrointestinal Hemorrhage (see Gastrointestinal Hemorrhage, [[Gastrointestinal Hemorrhage]]): occurs in 10% of cases
  • 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
    • Hepatic Infarction (see Hepatic Infarction, [[Hepatic Infarction]])
  • Pancreas
    • Acute Pancreatitis (see Acute Pancreatitis, [[Acute Pancreatitis]]): may be necrotizing
• Weight Loss (see Weight Loss, [[Weight Loss]])

Hematologic Manifestations

• Anemia (see Anemia, [[Anemia]])
• Elevated Erythrocyte Sedimentation Rate (ESR) (see Erythrocyte Sedimentation Rate, [[Erythrocyte Sedimentation Rate]])
• Eosinophilia (see Peripheral Eosinophilia, [[Peripheral Eosinophilia]])
• Hypocomplementemia: transient
• Leukocytosis (see Leukocytosis, [[Leukocytosis]])
• Thrombocytopenia (see Thrombocytopenia, [[Thrombocytopenia]])

Neurologic Manifestations

• Amaurosis Fugax (see Amaurosis Fugax, [[Amaurosis Fugax]])
• Delirium (see Delirium, [[Delirium]])
• Dizziness (see Dizziness, [[Dizziness]])
• Headache (see Headache, [[Headache]])
• Ischemic Cerebrovascular Accident (CVA) (see Ischemic Cerebrovascular Accident, [[Ischemic Cerebrovascular Accident]])
• Spinal Cord Ischemia/Infarction (see Spinal Cord Infarction, [[Spinal Cord Infarction]]): rare
• Transient Ischemic Attack (TIA) (see Transient Ischemic Attack, [[Transient Ischemic Attack]])

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]])

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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

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References

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