Cerebral arterial spasm after penetrating craniocerebral gunshot wounds: transcranial Doppler and cerebral blood flow findings.

OBJECTIVE: The goals of the study were to determine the incidence and time course of cerebral arterial spasm in patients with penetrating craniocerebral gunshot wounds, to study the relationship between vasospasm and subarachnoid hemorrhage (SAH) in these patients, and to evaluate the effects of vasospasm on outcome.
METHODS: Thirty-three patients with craniocerebral gunshot wounds underwent computed tomography at admission and then underwent transcranial doppler ultrasonography (TCD). Velocities in the middle cerebral artery and the extracranial internal carotid artery were measured. Vasospasm was defined as a middle cerebral artery velocity greater than 120 cm per second and a hemispheric index (ratio of middle cerebral artery to internal carotid artery velocity) greater than 3. Intravenous xenon-133 cerebral blood flow (CBF) studies were performed for 10 patients.
RESULTS: TCD was initiated, on average, 1.1 days after injury; 205 studies (mean, 6.3 studies/patient) were performed 0 to 33 days after injury. TCD showed vasospasm in 14 patients (42.4%). Xenon-133 studies performed within 24 hours of TCD measurements indicating spasm demonstrated normal or low CBF in three of five patients with spasm, ruling out hyperemia as the cause of elevated flow velocities in these three patients. Seven patients had unilateral vasospasm, and seven had bilateral spasm. Vasospasm was most prominent from Days 5 through 11. Vasospasm was distributed across all levels of injury severity, as defined by the Glasgow Coma Scale. Initial computed tomographic scans demonstrated SAH in all 14 patients with vasospasm but in only 9 of 19 without spasm (100 versus 47%, P < 0.0001, binomial distribution probability test). Outcomes for patients with vasospasm were slightly worse than for those without spasm (35.7 versus 47.4% good outcomes, respectively); however, this difference did not reach statistical significance (P = 0.12).
CONCLUSION: These findings demonstrate that delayed cerebral arterial spasm is a frequent complication in patients with craniocerebral gunshot wounds and is strongly associated with SAH. The frequency, time course, and severity of spasm are comparable with those observed with aneurysmal SAH and traumatic SAH caused by closed head injury. This study offers new insights into the hemodynamic pathophysiology after gunshot wounds to the brain and suggests that increased vigilance for vasospasm may be of benefit.