Relationship of perfusion pressure and size to risk of hemorrhage from arteriovenous malformations

Abstract

The relationship between the size of an arteriovenous malformation (AVM) and its propensity to hemorrhage is unclear. Although nidus volume increases geometrically with respect to AVM diameter, hemorrhages are at least as common, in small AVM's compared to large AVM's. The authors prospectively evaluated 92 AVM's for nidus size, hematoma size, and arterial feeding pressure to determine if these variables influence the tendency to hemorrhage. Small AVM's (diameter less than or equal to 3 cm) presented with hemorrhage significantly more often (p less than 0.001) than large AVM's (diameter greater than 6 cm), the incidence being 82% versus 21%. Intraoperative arterial pressures were recorded from the main feeding vessel(s) in 24 of the 92 patients in this series: 10 presented with hemorrhage and 14 presented with other neurological symptoms. In the AVM's that had hemorrhaged, the mean difference between mean arterial blood pressure and the feeding artery pressure was 6.5 mm Hg (range 2 to 15 mm Hg). In the AVM's that did not rupture, this difference was 40 mm Hg (range 17 to 63 mm Hg). Smaller AVM's had significantly higher feeding artery pressures (p less than 0.05) than did larger AVM's, and they were associated with large hemorrhages. It is suggested that differences in arterial feeding pressure may be responsible for the observed relationship between the size of AVM's and the frequency and severity of hemorrhage.

Natural course of the arteriovenous malformations of the brain initially presented by hemorrhage – analysis of a clinical series of 39 patients

“…ICH is the principal cause of morbidity and mortality, and the size of AVM, type of the venous drainage and raised blood pressure in supplying arteries are distinguished as the pathoanatomical predisposing factors for generating the bleeding from AVM (15,22,30).…”

Chiasmal and/or Optic Nerve Apoplexy Due to Rupture of Vascular Malformation -Case Report-

“…Furthermore, this high rebleeding rate may be related to size: pressure from the feeding arteries is significantly higher in small AVMs (diameter less than or equal to 3 cm) than in large AVMs, and probably contributes to the higher bleeding risk for small AVMs. 30) Optic Nerve Apoplexy Due to Rupture of AVM Most previous patients underwent surgery, mainly removal of the hematoma, and visual functions improved. However, visual functions after surgery deteriorated in 3 patients and were unchanged in 6.…”

Does treatment with N-butyl cyanoacrylate embolization protect against hemorrhage in cerebral arteriovenous malformations?

“…However, the reports found in the literature so far are inconclusive concerning the protective role of partial embolization 7,12,16,18,23 , since any residue of malformed vessels has the potential to cause future bleeding, no matter what percentage of the lesion was obliterated 15,18,22,23 . Partial embolization has also been thought to increase the risk of cAVM rupture, even in patients without a previous hemorrhagic event 8,10 .…”

“…After adjustment for several relevant factors, the association between deep lesion topography and occurrence of subsequent hemorrhage was confirmed (when compared to other locations), although the risk was reduced. This may be explained by a higher perfusion pressure, short arterial pedicles and venous drainage in deep lesions 10,26 .…”

“…The factors that are known to predispose to the occurrence of hemorrhage are smallsized lesions, deep or posterior fossa location, deep venous drainage, venous stenosis, elevated per-fusion pressure, and presence of aneurysms 2,3,[10][11][12][13] . Some investigators claim that presentation with seizures may be a protective factor against hemorrhage in untreated cAVMs.…”