Arteriosclerosis

Overview
  • Arteriosclerosis is a particular morphological pattern of vascular pathology observed in arterioles most often encountered as a result of chronic hypertension. The various etiologies and pathogenic mechanisms of hypertension can be found on its own page. Here we solely discuss the morphology of Arteriosclerosis which can occur in two patterns termed "Hyaline Arteriosclerosis" and "Hyperplastic Arteriosclerosis" depending on the intensity of hypertensive disease. Note that the term Arteriosclerosis should not be confused with that of Atherosclerosis which represents a completely different pathology and results from distinct pathogenic mechanisms. However, because chronic hypertension and atherosclerotic disease are often co-morbid, these two pathologies often occur together within a single patient.
Pathogenesis
  • Arteriosclerosis likely represents a com.bination of hypertensive damage to small blood vessels combined with the vasculature's attempt to adapt to the increased luminal pressure
Morphology
  • Hyaline Arteriosclerosis
    • Hyaline Arteriosclerosis is encountered in patients who display long-term modest elevations of systemic arterial pressure. Hyaline Arteriosclerosis is characterized by deposition of an amorphous pink, hyaline material within the arteriolar wall, resulting in its narrowing. The hyaline material likely represents both the leakage of plasma proteins into the arteriolar wall in addition to extracellular matrix production by vascular smooth muscle cells responding to the increased luminal pressure.
  • Hyperplastic Arteriosclerosis
    • Hyperplastic Arteriosclerosis is encountered in patients who display long-term extreme elevations of blood pressure as might be found in the context of malignant hypertension. Hyperplastic Arteriosclerosis is characterized by concentric reduplications of the arteriolar basement membrane by interspersed vascular smooth muscle cells, likely representing an adaptation to the intensely increased luminal pressure. This manifests as an "Onion-skin" like appearance to the thickened arteriolar wall which narrows or occasionally obliterates the vascular lumen.
Clinical Consequences
  • We briefly mention here that sclerosis of arteries significantly reduces their vascular compliance. As a consequence, a given change in the intra-arterial blood volume will result in larger swings in the intra-arterial blood pressure. Clinically, this can manifest as a larger-than-normal pulse pressure in affected arteries.