Pathological findings of saccular cerebral aneurysms—impact of subintimal fibrin deposition on aneurysm rupture

Masaaki Hokari, Naoki Nakayama, Hiroshi Nishihara, Kiyohiro Houkin

Research output: Contribution to journalArticle

3 Citations (Scopus)

Abstract

Although several studies have suggested that aneurysmal wall inflammation and laminar thrombus are associated with the rupture of saccular aneurysms, the mechanisms leading to the rupture remain obscure. We performed full exposure of aneurysms before clip application and attempted to keep the fibrin cap on the rupture point. Using these specimens in a nearly original state before surgery, we conducted a pathological analysis and studied the differences between ruptured and unruptured aneurysms to clarify the mechanism of aneurysmal wall degeneration. This study included ruptured (n = 28) and unruptured (n = 12) saccular aneurysms resected after clipping. All of the ruptured aneurysms were obtained within 24 h of onset. Immunostainings for markers of inflammatory cells (CD68) and classical histological staining techniques were performed. Clinical variables and pathological findings from ruptured and unruptured aneurysms were compared. Patients with ruptured or unruptured aneurysms did not differ by age, gender, size, location, and risk factors, such as hypertension, smoking, and hyperlipidemia. The absence or fragmentation of the internal elastica lamina, the myointimal hyperplasia, and the thinning of the aneurysmal wall were generally observed in both aneurysms. The existence of subintimal fibrin deposition, organized laminar thrombus, intramural hemorrhage, neovascularization, and monocyte infiltration are more frequently observed in ruptured aneurysms. Multivariate logistic regression analysis showed that ruptured aneurysm was associated with presence of subintimal fibrin deposition and monocyte infiltration. These findings suggest that subintimal fibrin deposition and chronic inflammation have a strong impact on degeneration of the aneurysmal wall leading to their rupture, and this finding may be caused by endothelial dysfunction.

Original languageEnglish
Pages (from-to)531-540
Number of pages10
JournalNeurosurgical Review
Volume38
Issue number3
DOIs
Publication statusPublished - 2015 Jul 18
Externally publishedYes

Fingerprint

Ruptured Aneurysm
Fibrin
Aneurysm
Rupture
Monocytes
Thrombosis
Inflammation
Histological Techniques
Rubber
Hyperlipidemias
Surgical Instruments
Hyperplasia
Logistic Models
Smoking
Regression Analysis
Staining and Labeling
Hemorrhage
Hypertension

Keywords

  • Aneurysms
  • Endothelial dysfunction
  • Pathology

ASJC Scopus subject areas

  • Surgery
  • Clinical Neurology

Cite this

Pathological findings of saccular cerebral aneurysms—impact of subintimal fibrin deposition on aneurysm rupture. / Hokari, Masaaki; Nakayama, Naoki; Nishihara, Hiroshi; Houkin, Kiyohiro.

In: Neurosurgical Review, Vol. 38, No. 3, 18.07.2015, p. 531-540.

Research output: Contribution to journalArticle

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