Study identifies trends in cerebral aneurysm treatment

Cerebrovascular disease is a leading cause of serious long-term disability, affecting as many as 700,000 people every year.

Subarachnoid hemorrhage (SAH) affects approximately 30,000 Americans every year, with 90 percent of all cases caused by cerebral aneurysms. Up to 6 percent of the U.S. population may be living with unruptured aneurysms. Aneurysms occur in all age groups, but the incidence increases steadily for individuals age 25 and older, is most prevalent in people ages 50 to 60, and about three times more prevalent in women. Of those who suffer ruptured aneurysms, about one half will not survive beyond 30 days, and an additional 25 percent will have some form of neurological deficit.

There are currently three treatment options for people with the diagnosis of a cerebral aneurysm: 1) Nonsurgical therapy; 2) Surgical therapy/clipping; and 3) Endovascular therapy/coiling. The most appropriate treatment of cerebral aneurysms, both ruptured and unruptured, is currently under debate. The debate centers primarily on efficacy and outcome comparisons of clipping versus coiling.

Recently, researchers undertook a study identifying trends in cerebral aneurysm treatment in the United States. To accomplish this task, the database of the Nationwide Inpatient Sample (NIS) from the Healthcare Cost and Utilization Project, Agency for Healthcare Research and Quality was reviewed. The NIS is the largest all-payer inpatient care database in the United States. The data includes 100 percent of discharges from a stratified random sample of nonfederal hospitals in 19 to 28 states. Thus, a representative 20 percent sub-sample of the entire United States is included in these hospital discharges, equating to approximately 8 million hospital stays from 1,000 hospitals.

The results of this study, Current Trends in the Treatment of Cerebral Aneurysms: Analysis of a Nationwide Inpatient Database, will be presented by Norberto Andaluz, MD, 3:50 to 4:00 p.m. on Wednesday, April 18, 2007, during the 75th Annual Meeting of the American Association of Neurological Surgeons in Washington, D.C. The co-author is Mario Zuccarello, MD.

In this study, researchers retrospectively reviewed data from the NIS database for the period 1993-2003; this period represents the earliest and latest available years of data at the time of the study. Multiple variables were subjected to logistic regression analysis for International Classification of Diseases (ICD)-9-CM codes related to SAH, unruptured aneurysm, and clipping and endovascular treatment of cerebral aneurysm. Using this approach, a sample of 506,040 patients was accrued for review. The following trends were noted:

• The number of discharges remained constant for patients with SAH but doubled for those with unruptured aneurysms.
• The number of discharges remained constant for aneurysm clippings but doubled for endovascular procedures.
• By the study's end, mortality decreased 20 percent for SAH and 50 percent for unruptured aneurysms.
• Increasing age was associated with statistically significant increased mortality, length of hospitalization, and mean hospital charges.
• Endovascular treatment was used more often in older patients.
• Teaching status and larger hospital size were associated with statistically significant better outcomes and lower mortality, especially in patients who underwent aneurysm clipping. These facilities were also associated with higher charges and longer hospital stays (a non-statistically significant finding).
• Endovascular treatment was associated with significantly higher mortality rates in small hospitals and steadily increasing morbidities.
• Surgical morbidity, length of hospitalization, and mean charges were statistically significantly higher for patients who underwent aneurysm clipping.

“The most noteworthy conclusions of this study indicate that the introduction of endovascular therapy equates to better overall results in the treatment of patients with cerebral aneurysms. Additionally, a multidisciplinary approach at large teaching centers appears to offer the best therapeutic paradigm,” stated Dr. Andaluz.

“While this study helps provides some insight into the ongoing debate of “clip versus coil” in the treatment of cerebral aneurysms, it also gives evidence that there is no definitive answer to this question. It depends on the individual patient – their age, clinical findings, and the type of facility in which they are treated,” concluded Dr. Andaluz.

Founded in 1931 as the Harvey Cushing Society, the American Association of Neurological Surgeons (AANS) is a scientific and educational association with more than 6,800 members worldwide. The AANS is dedicated to advancing the specialty of neurological surgery in order to provide the highest quality of neurosurgical care to the public. All active members of the AANS are certified by the American Board of Neurological Surgery, the Royal College of Physicians and Surgeons (Neurosurgery) of Canada or the Mexican Council of Neurological Surgery, AC. Neurological surgery is the medical specialty concerned with the prevention, diagnosis, treatment and rehabilitation of disorders that affect the entire nervous system, including the spinal column, spinal cord, brain and peripheral nerves.