Intra-aneurysmal pressure changes during angiography in coil embolization

Although elevation of blood pressure in aneurysms induced by injection of contrast medium has been postulated as a major cause of rerupture of ruptured cerebral aneurysms during angiography, no study has proved the elevation of intra-aneurysmal pressure because of difficulty in measuring the intra-aneurysmal pressure during angiography. The present study demonstrated intra-aneurysmal pressure to be raised by injection of contrast medium, using a microcatheter introduced into aneurysms.

To confirm the accuracy of pressure measurement through a microcatheter, we measured intra-aneurysmal pressure in a plastic model of an artery and an aneurysm during and after injection of contrast medium through a microcatheter and a needle inserted into the aneurysm. In a clinical study, intra-aneurysmal pressures were measured through the microcatheter in nine cerebral aneurysms of seven patients.

In the model experiment, changes in the pressure measured through the microcatheter correlated well with those observed through the needle. In the clinical study, intra-aneurysmal systolic pressures increased by 5-23 mm Hg immediately after injection of contrast medium for 1-3 s in four basilar tip, three internal carotid-ophthalmic, and one middle cerebral artery aneurysm, whereas no pressure change was observed in a posterior cerebral artery aneurysm. Systemic blood pressure during angiography remained unchanged in all cases.

This abruptly elevated intra-aneurysmal pressure by injection of contrast medium might cause rerupture of an aneurysm soon after rupture of the aneurysm, especially when the rupture site is fragile.