Emergent management of subarachnoid hemorrhage (SAH) is critical. An estimated 10-15 percent of patients die before reaching the hospital. Moreover, mortality rate reaches as high as 40 percent within the first week, and about 50 percent of patients who suffered an SAH die in the first six months.

SAH occurs when a blood vessel just outside the brain ruptures. The area of the skull surrounding the brain (the subarachnoid space) rapidly fills with blood. The sudden buildup of pressure outside the brain may also cause rapid loss of consciousness or death.

Symptoms of SAH include a sudden, severe headache that often starts at the back of the head and causes impaired or loss of consciousness, neck pain and nausea or vomiting. Sometimes this is described as the worst headache of one's life.

According to a recent study published in Neurosurgery, treating this severe type of stroke at high-volume stroke centers results in fewer deaths. In fact, the mortality rate after SAH is about one-fifth lower at high-volume hospitals. The study suggests that hospitals that treat more of these patients have better outcomes than low-volume hospitals with less experience.

Using data from a nationwide quality improvement program (the Get with the Guidelines-Stroke registry), the researchers identified approximately 32,000 SAH patients in 685 hospitals from April 2003 to March 2012. The study compared mortality rates and other outcomes for patients treated at hospitals with different volumes of SAH patients.

The number of SAH cases treated per year ranged from as low as four at the lowest-volume hospitals to 13 or more at the highest-volume hospitals. The risk of in-hospital death decreased as hospital volume of SAH cases increased — from 29.5 percent at the lowest-volume hospitals to 22.1 percent at the highest-volume hospitals. In the high-volume stroke centers, primarily Comprehensive Stroke Centers or Primary Stroke Centers, the mortality risk was one-fifth lower compared to the lowest-volume hospitals.

According to Dr. Shyam Prabhakaran, one of the main authors of the study, the results support efforts to regionalize stroke care so patients diagnosed with SAH after a computed tomography (CT) scan are transported to high-volume centers where they have the best chance of a good outcome.

So what makes the difference? Potential reasons these high-volume hospitals show better results may be that they offer both neurosurgical/neuroradiological expertise and have more resources and quality improvement systems than lower-volume centers. Other reasons include access to specialized services, level of staffing and organized multidisciplinary stroke teams.

One-third of patients who suffer an SAH will survive with good recovery, one-third will survive with a disability, and one-third will die. Treatment focuses on stopping the bleeding, restoring normal blood flow, relieving the pressure on the brain and preventing vasospasm.

The results of this study may have significant implications for regional stroke policies and procedures and affirm the recent recommendations that patients with SAH be treated at high-volume centers.