Microvascular pathological features of immediate perinidal parenchyma in cerebral arteriovenous malformations: giant bed capillaries

Abstract

Eighty-five percent of the AVMs studied showed the presence of huge, dilated capillaries, and 65% showed severe congestion of these capillaries. The authors have named these capillaries "giant bed capillaries." In this study capillary bleeding was shown in AVMs, and a pericapillary space was seen around some vessels. The brain parenchyma containing AVMs with these findings proved to be significantly ischemic.

Territorial and Microvascular Perfusion Impairment in Brain Arteriovenous Malformations

“…7 The inhomogeneous distribution of discrete perfusion abnormalities can be better explained by local differences in the arteriolar angioarchitecture than by the hemispheric asymmetry and the arterioarterial redistribution on a macrovascular level that we observed. Both levels of perfusion impairment are visible in Fig 3. The local CBF decrease is compatible with recent histologic reports of a perinidal dilated capillary network in 85%-100% of patients with AVM 24,25 and may be due to an exhausted compensatory mechanism. These capillaries are connected not only to the nidus, feeding arteries, and draining veins via arterioles and venules but also to normal capillaries, arterioles, and venules.…”

“…These capillaries are connected not only to the nidus, feeding arteries, and draining veins via arterioles and venules but also to normal capillaries, arterioles, and venules. The perinidal brain parenchyma has been reported to show significant ischemic changes, 24,25 though a previous diffusion-weighted imaging study did not reveal perinidal ischemia in unselected patients with AVM. 14 The conclusions that can be drawn from our study are limited by the low number of patients and high variability of brain AVMs.…”

Pathophysiology and Treatment of Brain AVMs*

“…The experimental evidence linking steal to reversible neurologic deficits is minimal [18] and prospective studies, however, do not confirm the improvement of neuropsychological function after flow normalization [22]. A local CBF decrease is compatible with recent histological reports of a perinidal dilated capillary network in 85-100% of AVM patients [23,24] and may be due to an exhausted compensatory mechanisms. These capillaries are connected not only to the nidus, feeding arteries, and draining veins, via arterioles and venules, but also to normal capillaries, arterioles, and venules.…”

“…These capillaries are connected not only to the nidus, feeding arteries, and draining veins, via arterioles and venules, but also to normal capillaries, arterioles, and venules. The perinidal brain parenchyma has been reported to be significantly ischemic in such cases [23,24]. A previous diffusion-weighted imaging study did not reveal perinidal ischemia in AVM patients [25].…”

Whole-Brain Perfusion CT Patterns of Brain Arteriovenous Malformations: A Pilot Study in 18 Patients

“…17 Dilated capillaries with gliotic changes have been identified in the immediate perinidal parenchyma; thus some of the symptoms attributed to the steal phenomenon may actually reflect symptoms related to the gliosis from chronic steal. 7,11 In our series, both focal neurologic deficit and seizure were seen with arterial steal. Pattern 1 (functional steal) was more often associated with seizures (5 of 7 cases), and pattern 2 (ischemic steal) was more often associated with focal neurologic deficits (3 of 4 cases).…”