Aneurysm: Causes

Pathogenesis (disease development)

Atherosclerosis (= intimal lesion/injury to the inner layer of a vessel) is the most common cause of aortic aneurysm (medial lesion/injury to the middle layer of a vessel). The pathogenesis is still very unclear. Of importance seems to be an increased activity of matrix metalloproteinases (MMPs) in affected patients. These regulate connective tissue homeostasis. Aneurysms of the vessels supplying the brain are located in the anterior circulation in most cases. Aneurysms of the thoracic aorta affect 50% of the ascending aorta (ascending portion of the thoracic aorta), and 40% affect the descending aorta (descending portion of the thoracic aorta). Aneurysms of the abdominal aorta are infrarenal (section located below the renal arteries) in up to 95%.

Etiology (Causes)

Aneurysm of the vessels supplying the brain

Biographic causes

  • Genetic burden
    • Genetic risk depending on gene polymorphisms:
      • Genes/SNPs (single nucleotide polymorphism; English : single nucleotide polymorphism):
        • SNP: rs10757278 in an intergenic region [cerebral aneurysm and abdominal aortic aneurysm].
          • Allele constellation: GG (1.3-fold).
          • Allele constellation: AA (0.77-fold)
  • Age – increasing age

Behavioral causes

  • Alcohol abuse (alcohol dependence)
  • Nicotine abuse (nicotine dependence) (applies to both sexes)
    • Proportion of female smokers with intracranial (“localized within the skull”) aneurysms is about four times higher than among women without aneurysms

Disease-related causes

Cardiovascular system (I00-I99)

  • Arterial hypertension (high blood pressure) (applies to both sexes).
    • Proportion of hypertensive women is about three times higher than among women without aneurysms

Medication

  • Local application of an intracavitary polymer containing carmustineNote: To avoid, care should be taken to ensure adequate distance between inserted platelets and vessels during surgical glioma treatment.

Thoracic aortic aneurysm

Biographical causes

  • Genetic burden – increased risk in first-degree relatives; 4-14% of these have aneurysm
    • Genetic diseases
      • Loeys-Dietz syndrome – aortic aneurysm syndrome with autosomal dominant inheritance (98-100% of these patients have an aneurysm).
      • Marfan syndrome – genetic disease that can be inherited both autosomal-dominant or isolated (as a new mutation); systemic connective tissue disease, which is notable mainly for tall stature, spider-limbedness and hyperextensibility of the joints; 75% of these patients have an aneurysm (pathological (pathological) bulge of the arterial wall).
      • Turner syndrome (synonyms: Ullrich-Turner syndrome, UTS) – genetic disorder that usually occurs sporadically; girls/women with this peculiarity have only one functional X chromosome instead of the usual two (monosomy X); et al. Among other things, with an anomaly of the aortic valve (33% of these patients have an aneurysm/diseased bulging of an artery); it is the only viable monosomy in humans and occurs approximately once in 2,500 female newborns.
  • Male gender
  • Age – increasing age (approximately 4.6% of people over 60 have an aneurysm)

Behavioral causes

  • Nicotine abuse (nicotine dependence)
  • Drug use
    • Cocaine

Disease-related causes

Cardiovascular system (I00-I99)

  • Anlage disorders of the aortic valve – bicuspid, unicuspid aortic valve, Turner syndrome.
  • Aortitis – inflammation of the aorta (30-67% of these patients have aneurysm).
  • Arterial hypertension (high blood pressure).
  • Atherosclerosis (arteriosclerosis, hardening of the arteries)
  • Gsell-Erdheim syndrome (idiopathic median necrosis of the aorta) – tissue death of unclear cause of the middle vessel wall of the aorta.
  • Structural weakness of the media/middle layer of the vessels (mediadegeneration).
  • Syndrome of bicuspid aortic valve: here, in addition to the aortic valve, the ascending aorta (ascending aorta) is also involved; patients with this condition develop an aneurysm of the ascending aorta in approximately 26% of cases
  • Takayasu arteritis – granulomatous vasculitis (vascular inflammation) of the aortic arch and the outgoing great vessels; almost exclusively in young women.
  • Vasculitis (vascular inflammation).

Infectious and parasitic diseases (A00-B99).

  • Syphilis (lues)

Medication

Other causes

  • Gravidity (pregnancy) – risk of acute aortic dissection (aneurysm dissecans aortae: splitting of the wall layers of the aorta): in 61, 5% of all cases shortly after birth – mostly within 30 days after delivery; before birth 15.1%; in 23, 4% of cases during delivery; mortality was particularly high when the dissection (splitting) occurred in the aorta (8.6%)
  • Iatrogenic (cardiac catheterization)

Abdominal aortic aneurysm

Biographical causes

  • Genetic predisposition – increased risk in first-degree relatives
    • Genetic risk dependent on gene polymorphisms:
      • Genes/SNPs (single nucleotide polymorphism; English : single nucleotide polymorphism):
        • Genes: DAB2IP
        • SNP: rs7025486 in gene DAB2IP
          • Allele constellation: AG (1.2-fold).
          • Allele constellation: AA (1.4-fold)
        • SNP: rs10757278 in an intergenic region.
          • Allele constellation: GG (1.3-fold).
          • Genetic diseases genetic diseases allele constellation: AA (0.77-fold).
    • Genetic diseases
      • Ehlers-Danlos syndrome (EDS) – genetic disorders that are both autosomal dominant and autosomal recessive; heterogeneous group caused by a disorder of collagen synthesis; characterized by increased elasticity of the skin and unusual tearability of the same.
      • Loeys-Dietz syndrome – aortic aneurysm syndrome with autosomal dominant inheritance, which is caused by a mutation of the TGF-β receptor (98-100% of these patients have aneurysms)
      • Marfan syndrome – genetic disease, which can be inherited both autosomal dominant or occur sporadically (as a new mutation); systemic connective tissue disease, which is mainly notable for tall stature; 75% of these patients have an aneurysm

Behavioral causes

  • Nicotine abuse (nicotine dependence)

Disease-related causes

Congenital malformations, deformities, and chromosomal abnormalities (Q00-Q99).

  • Anlage disorders of the aortic valve
  • Ehlers-Danlos syndrome (see “Biographical Causes” below).
  • Loeys-Dietz syndrome (see below “Biographical Causes”).
  • Marfan syndrome (see below “Biographical Causes”).

Respiratory system (J00-J99)

Cardiovascular system (I00-I99)

Infectious and parasitic diseases (A00-B99).

  • Aortitis, e.g., due to syphilis (lues).

Laboratory diagnoses – laboratory parameters that are considered independent risk factors.

  • Hypercholesterolemia

Medication