Ahead of Print: SVASONA Secondary Analysis

Background: Little is known about variables associated with over-drainage complications and neuro-functional and health-related quality of life outcomes in idiopathic normal-pressure hydrocephalus (iNPH) patients after shunt surgery.

Objective: To identify candidate demographic and disease-specific predictors of over-drainage and patient-centered outcomes, allowing for a more personalized care of subjects with iNPH.

Methods: This is a secondary analysis of the dataset of the SVASONA study, a multi-center randomized trial comparing gravitational versus conventional gravitational valves for treating iNPH. We evaluated the association between baseline items and the incidence of over-drainage, using different endpoint definitions.

Results: We identified only few variables associated with a possibly increased risk of over-drainage. Apart from using conventional rather than gravitational valves, longer duration of surgery and female gender were associated with a higher risk of clinical signs and symptoms suggestive of over-drainage (hazard ratio [HR] 1.02, 95% confidence interval [CI] 1.01-1.04 and 1.84, 95% CI 0.81-4.16). The occurrence of clinical symptoms of over-drainage, and the need for exchanging a programmable by a gravitational valve may adversely affect disease-specific outcomes like the Kiefer Score.

Conclusion: Few, if any, baseline and treatment characteristics may be helpful in estimating the individual risk of complications and clinical outcomes after shunt surgery for iNPH. Patients should be informed that longer surgery for any reason may increase the risk of later over-drainage. Also, women should be counseled about a gender-associated extra risk of developing clinical symptoms of over-drainage, although the latter cannot be distinguished from a generally higher prevalence of headaches in the female population.

From: Predictors of Subsequent Over-Drainage and Clinical Outcomes After Ventriculo-Peritoneal Shunting for Idiopathic Normal Pressure Hydrocephalus by Meier et al.

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