The influence of vascular pressure and angiographic characteristics on haemorrhage from arteriovenous malformations

Background. The present study was designed to determine whether there is a physiological explanation for the predisposition of patients with certain a ngiographic characteristics to haemorrhage from cerebral arteriovenous malf ormations (AVMs). Methods. Intra-operative measurement of feeding artery pressure (FAP) and i ntravascular pressures in the draining venous system [draining vein pressur e (DVP) and cranial sinus pressure (SIP)] were performed for 30 AVM cases u sing direct puncture of the vessels. The correlation between pressures and previously described angiographic characteristics predisposing to haemorrha ge were evaluated. Findings. Small nidus size and only one draining vein increased the risk of haemorrhage. FAP and DVP are both inversely related to the number of drain ing veins and the size of the AVMs. DVP was significantly higher in AVMs wi th haemorrhage (23.1 +/- 8.7 mmHg) than in those without (13.5 +/- 4.4), as was FAP (58.6 +/- 12.8 as opposed to 38.7 +/- 4.7) (p < 0.05). Moreover, t he difference between systemic blood pressure and the FAP with haemorrhagic AVMs (17.0 +/- 9.5 mmHg) was significantly lower than that in nonhaemorrha gic cases (33.7 +/- 5.5) (p < 0.05). The pressure difference between the fe eding artery and draining vein was not significant between the haemorrhagic and nonhaemorrhagic groups. There was no significant difference of SP betw een haemorrhagic and nonhaemorrhagic patients. Interpretation. The present study suggests that a high DVP probably induced by high resistance in the venous drainage system, as well as a high FAP, m ay contribute to the development of haemorrhage from AVMs, and physiologica lly supports previous reports that small AVMs and AVMs with only one draini ng vein are susceptible to haemorrhage.