Changes in Treatment Fail to Budge Outcomes for Unruptured Intracranial Aneurysms

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Despite growing use of endovascular coiling instead of surgical clipping to treat unruptured intracranial aneurysms, outcomes have not improved since the mid 1990s, according to research published online August 18, 2011, ahead of print in Stroke. The primary reasons appear to be that coiling is increasingly more likely to occur at low-volume rather than high-volume centers and that even the busiest centers are seeing decreases in microsurgical volume.

Researchers led by Brad E. Zacharia, MD, of Columbia University Medical Center (New York, NY), retrospectively examined data from New York’s Statewide Planning and Research Cooperative System (SPARCS) on hospital discharges for unruptured intracranial aneurysms during 2 periods: 1995 to 2000 (n = 2,200) and 2005 to 2007 (n = 3,132). The investigators compared rates of endovascular coiling and surgical clipping between the 2 cohorts, analyzing hospital variables and discharge outcome.

Aneurysms Now More Likely to Be Treated

Between the study periods, the overall treatment rate of unruptured intracranial aneurysms more than doubled, and use of coiling in particular increased substantially. Other notable changes from one time period to the next were that patients who underwent surgical coiling were increasingly more likely to do so at high-volume centers, while those who underwent endovascular coiling were less likely to be treated at high-volume centers (table 1).

Table 1. Trends in Management of Unruptured Intracranial Aneurysm

 

1995-2000

2005-2007

P Value

Treatment Rate per 100,000
Overall
Endovascular Coiling

 
1.59
0.36

 
3.54
1.98

 
< 0.0001
< 0.0001

Proportion Treated at High-Volume Centers
Surgical Clipping
Endovascular Coiling

 
 
55.8%
94.8%

 
 
78.8%
84.5%

 
 
< 0.0001
< 0.0001


Discharge outcomes did not improve overall from one era to the next (79% vs. 81%, P = 0.168). In fact, the rate of patients being discharged to home after clipping declined from the earlier to the later period (76.3% vs. 71.7%, P = 0.0132), whereas good outcomes for coiling remained relatively stable (89.7% vs. 87.7%; P = NS).

Multivariate analysis identified 3 independent predictors of good discharge outcome:

  • White vs. other race (OR 1.67; P = 0.0007)
  • Hospital volume (OR 1.04 per 10 additional cases; P < 0.0001)
  • Definitive treatment by coiling (OR 3.94; P < 0.0001)

On the other hand, older age was associated with worse outcomes (OR 0.61 per 10-year increase; P < 0.0001), as was direct admission from the emergency room (OR 0.41; P = 0.0004). Interestingly, when the percentage of aneurysm patients who were treated with coiling increased at a given center, the risk of poor outcome also tended to increase (OR 0.92 per 10% additional coiling; P = 0.05).

Shifts in Treatment Patterns, Surgical Expertise

According to the study authors, the findings confirm that endovascular treatment provides better discharge outcomes compared with surgery but also highlight how the evolution in treatment strategy has failed to improve overall results. “Factors contributing to this failure appear to be the dramatic shift in coiling venue from high-volume centers to low-volume centers where outcomes are inferior, and decreasing surgical volume, even in the busiest centers, accompanied by an overall worsening in microsurgical results,” they write.

Nicholas C. Bambakidis, MD, of University Hospitals Case Medical Center (Cleveland, OH), offered another perspective.

“The fact that open surgical treatment results are poorer in the later epoch of the study is a direct reflection of the selection bias incurred in the study and is a result of cherry-picking of straightforward cases by low-volume endovascular treatment centers,” he told TCTMD in an e-mail communication. “This leaves extremely challenging cases for open surgical therapy.”

Moreover, many neurosurgeons trained in the era when open surgery was commonly practiced are now retired, he added. “This has been accompanied by a relative paucity of such experience in current neurosurgical training programs, leaving many fewer experienced aneurysm surgeons in active practice.”

Centralizing Care Is Key

In an e-mail communication, Dr. Zacharia said that the study findings support “greater centralization of care.”

“There are certainly instances wherein aneurysms can be treated at low-volume centers,” he continued. “However, we would advocate for a system-wide initiative to refer patients with unruptured intracranial aneurysms to large-volume centers with physicians who have expertise in both open and endovascular management of these lesions.”

Dr. Bambakidis agreed with this approach, stressing that technological advances have not translated into better outcomes. Coiling, he said, continues have questionable durability and occasionally requires retreatment.

“[T]he question is not how to achieve better outcomes for coiling but how to achieve better outcomes in the treatment of all patients regardless of treatment modality. . . . Low-volume centers generally offer only one treatment modality (ie, endovascular coiling), leading to [suboptimal] treatment of lesions best treated alternatively (ie, with open clipping),” Dr. Bambakidis explained. “Better outcomes are achieved by centralizing care in high-volume centers able to offer both coiling and clipping modalities.”

 


Source:
Zacharia BE, Ducruet AF, Hickman ZL, et al. Technological advances in the management of unruptured intracranial aneurysms fail to improve outcome in New York State. Stroke. 2011;Epub ahead of print.

 

 

Related Story:

Changes in Treatment Fail to Budge Outcomes for Unruptured Intracranial Aneurysms

Despite growing use of endovascular coiling instead of surgical clipping to treat unruptured intracranial aneurysms, outcomes have not improved since the mid 1990s, according to research published online August 18, 2011, ahead of print in Stroke. The primary reasons appear
Disclosures
  • The study was internally funded by the Columbia University Department of Neurological Surgery.
  • Drs. Zacharia and Bambakidis report no relevant conflicts of interest.

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