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April 21, 2024


Though pressures tend to be greater in high-BMI patients, stenting provided more relief from hypertension and stenosis than in those with lower BMIs.


Among patients being treated for idiopathic intracranial hypertension (IIH), a higher body mass index (BMI) value is associated with greater intracranial venous pressure and trans-stenosis pressure gradients. But patients with high BMIs also respond to venous stenting better, achieving greater reductions in pressure and pressure gradients than those with lower BMIs, according to a retrospective study published online June 22, 2017, ahead of print in Neurosurgery.

Case series have reported that stent implantation can lead to symptom improvement, resolution of increased intracranial pressure, and improvement in papilledema for patients with IIH, Daniel M.S. Raper, MBBS (University of Virginia, Charlottesville, VA), and colleagues say. “Nevertheless, prior studies have suggested that the efficacy of [stenting] could be limited for obese or morbidly obese patients, in which extrinsic compression of the venous sinuses may be a risk factor for ongoing venous outflow obstruction and symptomatic recurrence after [treatment].”

In their retrospective cohort study using a prospectively maintained database, Raper et al identified 89 patients who underwent angiographic workup for IIH. Of these, 50 underwent placement of 70 intracranial venous stents, 47 of whom were female. Overall, four patients were of normal weight (BMI ≤ 25 kg/m2), eight were overweight (BMI 25-30 kg/m2), 19 were obese (BMI 30-40 kg/m2), and 19 were morbidly obese (BMI ≥ 40 kg/m2).

Increasing BMI was significantly linked with a higher maximum mean intracranial venous pressure (P = 0.013) and a higher trans-stenosis pressure gradient (P = 0.043) prior to treatment. The degree of improvement in both of these parameters were greatest in obese and morbidly obese patients. On the other hand, maximum poststent mean intracranial venous pressure, clinical outcomes, and rates of stent-adjacent stenosis requiring treatment were all independent of BMI.

Outcomes by BMI

 

Normal

(n = 4)

Overweight

(n = 8)

Obese

(n = 19)

Morbidly Obese

(n = 19)

Maximum Prestent Mean Intracranial Venous Pressure, mm Hg

20.0

23.4

29.5

32.4

Maximum Poststent Mean Intracranial Venous Pressure, mm Hg

12.7

12.9

21.7

16.7

Prestent Mean Trans-Stenosis Pressure Gradient, mm Hg

9.7

14.2

17.6

18.1

Poststent Mean Trans-Stenosis Pressure Gradient, mm Hg

1.5

4.0

5.7

3.2


“The efficacy of [stenting] does not appear to be diminished by obesity,” conclude the authors, noting that in fact it carries greater reductions in pressure and pressure gradient for higher-BMI patients.

Is It BMI or Stenosis Configuration?

This is the fourth published investigation of parameters, including BMI, that might help predict outcomes of venous stenting, David A. Kumpe, MD, (University of Colorado Anschutz Medical Campus, Aurora, CO), told Neurovascular Exchange in an email. To date, the data suggesting the predictive power of BMI have been equivocal. Ahmed et al concluded BMI was unrelated to outcomes, while Goodwin et al concluded the opposite, albeit in a small series of only 18 patients. Kumpe himself published a study suggesting that BMI does not correlate independently with hemodynamic outcome.

“Stents are placed in patients whose vision is threatened by papilledema,” Kumpe explained. “Obesity is certainly a factor in IIH, but fortunately stenting seems to help eliminate papilledema regardless of BMI. We found too much overlap of the various clinical parameters between long- term failures and successes for any parameter to be predictive of outcome.”

Kumpe added that it would be helpful if other investigators analyzed their series, as he did, in terms of extrinsic versus intrinsic stenosis and whether men and other atypical patients (ie, those who are slender and/or are over 50 years of age) have almost exclusively intrinsic stenosis. “We think that extrinsic stenosis is most predictive of failure,” he noted.

“What you want is a parameter or combination [of parameters] which predicts whether you should stent and where/how much to stent,” he concluded. “We think the configuration of the stenosis is the best predictor of these looked at so far.”

 


Source:

Raper DMS, Ding D, Buell TJ, et al. Effect of body mass index on venous sinus pressures in idiopathic intracranial hypertension patients before and after endovascular stenting. Neurosurgery. 2017;Epub ahead of print.

 

Disclosures:

Raper and Kumpe report no relevant conflicts of interest.

 

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