Study Assesses Neurointerventional Procedure Volume in US Hospitals

Download this article's Factoid in PDF (& PPT for Gold Subscribers)


Adequate experience with neurointerventional procedures is critical for any hospital seeking to qualify as a comprehensive stroke center, yet hardly any US institutions meet the necessary volume criteria, according to a study appearing online March 1, 2012, ahead of print in Stroke. The authors claim that the results argue in favor of centralizing stroke services in large, regional centers.

Establishment of comprehensive stroke centers is being considered for patients who require high intensity care, including interventional therapies. To assess whether current hospitals qualify as a stroke center according to existing recommendations, researchers led by Mikayel Grigoryan, MD, of the University of Minnesota (Minneapolis, MN), looked at procedural volume in hospitals in the Nationwide Inpatient Sample database, reviewing roughly 1,000 hospitals per year from 2005 through 2008.

Seven neurointerventional/neurosurgical procedures were reviewed along with the minimum annual volume criteria for meeting comprehensive stroke center designation:

  • Cervicocerebral angiography (100 procedures)
  • Endovascular treatment of acute ischemic stroke (10 procedures)
  • Carotid angioplasty/stent placement (CAS; 25 procedures)
  • Intracranial angioplasty/stent placement (10 procedures)
  • Aneurysm embolization (30 procedures)
  • Carotid endarterectomy (CEA; 25 procedures)
  • Surgical treatment of aneurysm (10 procedures)

Less than 10% of US hospitals had high enough volume for any single procedure with the exception of CEA, where over a quarter of centers met the benchmark. Overall, less than 1% of hospitals met the criteria for all procedures (table 1).

Table 1. Hospitals Meeting Procedural Volume Requirements

 

2005
(n = 1,035)

2008
(n = 1,038)

Cervicocerebral Angiography

7.0%

7.8%

Endovascular AIS Treatment

0.4%

2.6%

CAS

3.0%

4.9%

Intracranial Angioplasty

0.3%

1.3%

Aneurysm Embolization

1.3%

2.6%

CEA

28.7%

27.3%

Aneurysm Surgery

3.8%

3.2%

Meeting Criteria for All Procedures

0.2%

0.7%

Abbreviation: AIS, acute ischemic stroke.

The total number of endovascular procedures increased across the study period with the exception of intracranial angioplasty/stent placement (204 cases in 2005 to 374 in 2008; P = NS). Procedures that increased included endovascular treatment of acute ischemic stroke (285 to 1,018; P < 0.001), CAS (2,567 to 3,516; P = 0.021), and aneurysm embolization (1,356 to 2,686; P = 0.004).

Dr. Grigoryan and colleagues also divided hospitals into “high” and “low” volume centers. High volume was defined as performing at least 100 cervicocerebral angiograms and meeting at least 1 other procedural criterion. There were 79 high volume centers that were compared with 958 low volume centers. High volume centers were more likely to be teaching hospitals (70.9% vs. 13.1%; P < 0.001) located in urban areas (69.6% vs. 12.3%; P < 0.001) and to have large bed size (79.7% vs. 26.9%; P < 0.001).

On multivariable analysis, both urban location/teaching status (OR 8.92; CI 4.3-18.2; P < 0.001) and large bed size (OR 4.40; 95% CI 2.0-9.5; P < 0.001) remained independent predictors of high volume after adjusting for factors including age, gender, cerebrovascular risk factors, and stroke subtype.

“There are very few hospitals in the United States that meet all the neurointerventional procedural volume criteria for all endovascular procedures recommended to ensure adequate operator experience,” the researchers conclude. “Our results support the creation of specialized regional centers for ensuring adequate procedural volume within treating hospitals.”

‘Hey, Wait a Minute’

Despite finding relatively few hospitals able to provide adequate comprehensive neurointerventional services, the study authors cite a large number of institutions hiring physicians seeking neurointerventional training. Given this discrepancy, “our results would suggest a more appropriate balance in number of trainees, current hiring, and procedural volume,” Dr. Grigoryan and colleagues recommend.

In a telephone interview with TCTMD, Philip M. Meyers, MD, of Columbia University Medical Center (New York, NY), agreed that “right now we’re in a phase where there are innumerable people flooding into the neurointerventional field, and this study is saying, ‘Hey, wait a minute, There really aren’t that many procedures to be done.’”

Dr. Meyers advocated a system of regional institutions like with current US trauma centers. “It’s the exact opposite of the argument that every little hospital should be doing stroke intervention,” he said. “What we’re finding is that it really should be concentrated in major centers where they have the experience and breadth and depth of all the neuro-intensive care services to ensure good outcomes.”

A Different Message

But Jay Yadav, MD, of the Piedmont Heart Institute (Atlanta, GA), disagreed. “The message, to me, is somewhat different,” he told TCTMD in a telephone interview. “You can’t have an incredibly centralized system for an acute disease state. That works fine for elective procedures, but for diseases that happen unexpectedly, are somewhat randomly distributed and need to be treated within hours, you have to have a treatment that can be delivered in geographic proximity.”

He pointed out the low number of hospitals that met all neurointerventional volume criteria in 2008. “According to this, you would only have seven centers in the United States treating acute stroke. Do you think that’s adequate?” Dr. Yadav asked, adding that a valid comparison can be made with how acute MIs are treated in cardiology. “There are about 800,000 acute strokes each year compared with 1.1 million acute MIs. There aren’t that many more heart attacks than strokes, and yet you have thousands of hospitals that do acute angioplasty for acute MI.”

The difference, Dr. Yadav added, is that in cardiology there was already a baseline level of interventional experience and training in the nonacute setting that could transfer to the acute setting, something that does not occur with stroke.

Stroke-MI Analogy Flawed?

But according to Dr. Meyers, the stroke-MI analogy is flawed. “The reality is that relatively few of those 800,000 stroke patients actually need an endovascular procedure,” he said. “It’s so different from cardiac disease. In the coronaries, once you revascularize the vessel, the patient actually gets better. For the brain, if you reopen the vessel after a stroke, that’s only the first step. There are a lot of pitfalls and things that need to be managed in a specialty ICU.”

Nevertheless, Dr. Yadav maintained that “it’s not as complicated as these guys make out.

“The way we handle [an acute MI] is after the artery is open, you get transferred. The same thing can happen with stroke. After your artery is open at your local or semiregional hospital, then you get transferred to the Mecca,” he continued. “To me, this study means we need to add more hospitals and more training, not that there aren’t enough procedures to go around, so let’s not have any more people do them.”

Dr. Yadav added that he was confused by the study’s methodology, noting that the number of annual procedures may have been severely underestimated. “I can tell you that for endarterectomy, we know that in 2008 there were 178,000 procedures performed in the United States,” he said. “I’m thinking that these numbers [in the study] are based on this Nationwide Inpatient Sample, but this is an issue that could apply to all the procedure categories.”

 


Source:
Grigoryan M, Chaudhry SA, Hassan AE, et al. Neurointerventional procedural volume per hospital in United States: Implications for comprehensive stroke center designation. Stroke. 2012;Epub ahead of print.

 

 

Related Stories:


 

Click here for a listing of companies that provide support to the Cardiovascular Research Foundation, owner and operator of TCTMD.

Jason R. Kahn, the former News Editor of TCTMD, worked at CRF for 11 years until his death in 2014…

Read Full Bio
Disclosures
  • Drs. Grigoryan, Meyers, and Yadav report no relevant conflicts of interest.

Comments