The vasodilatory effect of intra-cisternal infusion of magnesium sulfate solution was evaluated in 10 patients with symptomatic vasospasm after aneurysmal subarachnoid hemorrhage (SAH) who underwent early clipping surgery. Cisternal drainage was installed in the prepontine and/or sylvian fissures. Carotid angiography was performed immediately after the onset of symptomatic vasospasm, then intracisternal infusion of 15 mmol/l magnesium sulfate in Ringer solution was started at 20 ml/hr and continued until day 14. Irrigation was performed from the cisternal tube (inlet) to the spinal drainage (outlet). The cerebrospinal fluid magnesium ion concentration (1.2 ± 0.2 mEq/l) significantly increased after the infusion therapy (6.0 ± 1.7 mEq/l, p º 0.001). Repeat angiography showed vasodilatory effect on the spastic cerebral arteries at 3 hours after the infusion, especially in the arteries near to the site of cisternal drainage placement. The magnesium infusion also caused decreased mean arterial blood velocity in the spastic arteries in 6 of the 7 measured patients (162 ± 38 cm/sec to 114 ± 42 cm/sec, p º 0.001). Finally, 5 of the 10 patients achieved good recovery, 1 patient had moderate disability, 1 patient became severely disabled due to meningitis, and 3 patients were vegetative or dead, due to failure of magnesium irrigation in 1 patient and advanced age in the other 2 (more than 80 years old). This preliminary study indicates that intra-cisternal infusion of magnesium sulfate solution has vasodilatory effect on the spastic cerebral arteries after aneurysmal SAH.
The reversible effect of an intracisternal injection of MgSO(4) solution on the spastic artery requires CSF Mg(++) concentrations > 3 mEq/L. The vasodilatory effect continues for 3-6 hours after injection. These results suggest that the continuous infusion or intermittent intracisternal injection of MgSO(4) is needed to maintain the optimal CSF Mg(++) concentration and constantly ameliorate cerebral vasospasm.
Intracisternal MgSO(4) therapy using a microcatheter from the lumbar spine may be effective against vasospasm in the clinical setting of endovascular treatment of ruptured aneurysm.
The effect of irrigation with artificial cerebrospinal fluid (CSF) containing various magnesium ion (Mg2+) concentrations on vasospastic arteries was investigated in the dog. Cerebral vasospasm was induced by the experimental subarachnoid hemorrhage model in 15 beagle dogs. Cisternal irrigation was performed for 1 hour via a microcatheter placed in the cisterna magna with commercially available artificial CSF (ARTCEREB®) with physiological concentration of Mg2+ (2.2 mEq/l) (ACM group, n = 5), ARTCEREB solution without Mg2+ (ACR group, n = 5), and ARTCEREB solution with higher Mg2+ concentration (5 mEq/l) (ACMM group, n = 5). CSF electrolyte concentrations and the diameters of the basilar and vertebral arteries were measured. In the ACM group, no changes were detected in either CSF Mg2+ concentration or arterial diameters. In the ACR group, the CSF Mg2+ decreased significantly to 0.8 ± 0.07 mEq/l from the baseline value of 1.4 ± 0.03 mEq/l, and both basilar and vertebral artery diameters were significantly decreased to 0.61 ± 0.18 mm and 0.57 ± 0.23 mm from their baseline values of 0.74 ± 0.22 mm and 0.68 ± 0.17 mm, respectively. In the ACMM group, the CSF Mg2+ significantly increased to 2.4 ± 0.15 mEq/l from the baseline value of 1.4 ± 0.05 mEq/l, and both basilar and vertebral artery diameters were significantly increased to 0.84 ± 0.19 mm and 0.90 ± 0.22 mm from their baseline values of 0.71 ± 0.21 mm and 0.69 ± 0.24 mm, respectively. Irrigation with artificial CSF solution without Mg2+ causes vasoconstriction of the cerebral artery. Irrigation with artificial CSF with appropriate Mg2+ concentration is essential, especially in patients with subarachnoid hemorrhage.
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