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Clinical and Morphological Forms of Atherosclerosis

Atherosclerosis

For medical students2 min readUpdated 2026-10-10

Atherosclerosis is characterized by steady progression and a wave-like course. The clinical presentation and disease severity directly depend on the vascular beds affected by plaques and the degree of arterial lumen obstruction.

Typical targetsAortic arch and abdominal aorta, coronary, cerebral, renal, carotid, and lower extremity arteries.
Wave-like courseFatty streaks and severe calcification can coexist within the same blood vessel simultaneously.
Acute occlusionRapid lumen obstruction due to a complicated plaque inevitably leads to infarction or gangrene.
Steal syndromeBlood flow compensation in the stenotic area occurs at the expense of adjacent organ perfusion.

Preferred Localization and Course

The pathological process in atherosclerosis targets specific vascular beds. Typical sites for plaque formation include the aortic arch and abdominal aorta, coronary arteries of the heart, cerebral vessels, renal arteries, as well as carotid and lower extremity arteries.

A key feature of the disease is its wave-like, progressive course. In practice, pathologists often find a combination of various stages of atherosclerosis within a single examined vessel. Early changes such as lipid spots can lie adjacent to advanced processes with prominent calcification.

Stage of Complicated Lesions

As the disease progresses, the fibrous plaque becomes unstable and undergoes destruction. This stage involves three key sequential processes:

Morbid anatomy of complicated arterial lesions also frequently reveals intraplaque hemorrhage and mural thrombi covering the defect.

Clinical and Anatomical Consequences

Changes in fibrous plaque structure inevitably lead to stenosis, thrombosis, and complete arterial occlusion. Clinical manifestations depend on the extent of the process and follow three main scenarios:

  1. Slow stenosis. The vessel lumen narrows gradually, causing progressive tissue ischemia. This results in atrophy, sclerosis, and chronic vascular insufficiency. The body attempts to compensate for oxygen deprivation via collateral circulation. This blood redistribution in adjacent beds can lead to steal syndromes, where blood flow in the stenotic zone is maintained solely by compromising perfusion in nearby organs.
  2. Rapid occlusion. Typically associated with a complicated plaque (e.g., acute thrombosis). This causes acute ischemia resulting in infarction or gangrene.
  3. Atherosclerotic aneurysm. The affected arterial wall loses elasticity, stretches, and balloons outward. The primary risks of this condition are dissection and rupture, followed by massive hemorrhage.

Complications and Outcomes

The clinical and morphological forms of atherosclerosis determine the most frequent and dangerous complications encountered in practice. These include:

The outcome is frequently fatal. Patient prognosis depends on three key factors: the exact localization of the lesion, the caliber of the involved artery, and the acuteness of the pathological process.

Mnemonic

To remember the triad of complicated lesion stages, use the acronym AIC: Atheromatosis, Ilceration (Ulceration), Calcification.

Frequently asked questions

What are the main clinical and morphological forms of atherosclerosis?

The main clinical and morphological (clinical-anatomical) forms of atherosclerosis are classified by the predominant localization of the lesion:

  • Atherosclerosis of the aorta;
  • Coronary artery atherosclerosis (cardiac form) — the morphological basis of IHD;
  • Cerebral artery atherosclerosis (cerebral form) — the basis of ischemic cerebrovascular accidents;
  • Renal artery atherosclerosis (renal form) — atherosclerotic nephrosclerosis;
  • Intestinal artery atherosclerosis — with potential development of bowel gangrene;
  • Lower extremity artery atherosclerosis — leading to chronic arterial insufficiency, ulcers, and gangrene.
What macroscopic stages of atherosclerosis development are distinguished in pathology?

Pathology distinguishes three major macroscopic stages of atherosclerosis:

  • Stage of fatty spots and streaks — macroscopic yellow spots and lines that do not rise above the intimal surface;
  • Stage of fibrous plaques — formation of a plaque protruding into the vessel lumen and narrowing it;
  • Stage of complicated lesions — includes atheromatosis, ulceration, and calcification (atherocalcinosis).
What are the microscopic stages of atherosclerosis morphogenesis?

The morphogenesis of atherosclerosis includes the following sequential microscopic stages:

  • Pre-lipid stage — intimal injuries visible only under an electron microscope;
  • Lipoidosis stage — focal intimal infiltration by lipids and lipoproteins forming foam cells;
  • Liposclerosis stage — connective tissue proliferation in lipid deposition areas;
  • Atheromatosis stage — breakdown of central plaque lipid masses forming amorphous debris;
  • Ulceration stage — destruction of the plaque cap forming an atheromatous ulcer;
  • Atherocalcinosis stage — deposition of calcium salts into atheromatous masses and fibrous tissue.
What shapes of aneurysms occur in aortic atherosclerosis?

Atherosclerotic aortic aneurysms are most commonly fusiform, and occasionally saccular in shape.

What does the presence of both lipid spots and calcification in the same vessel indicate?

Such a combination of different stages within a single artery directly proves the wave-like and progressive nature of atherosclerosis.

How does 'steal syndrome' develop?

During slow arterial stenosis, collateral circulation develops. Blood flow compensation in the ischemic zone occurs through blood redistribution, which impairs perfusion in adjacent, healthy organs.

What is the difference in consequences between slow stenosis and rapid occlusion?

Slow narrowing causes progressive ischemia leading to atrophy, sclerosis, and chronic insufficiency. Rapid occlusion (usually due to a complicated plaque) causes acute blood deprivation, leading to necrosis—infarction or gangrene.

What factors determine the outcome of atherosclerosis?

The likelihood of a fatal outcome and the severity of consequences depend on the plaque location, the caliber of the affected artery, and the acuteness of vascular insufficiency.

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