Title: Intervention To Preserve Vision In Idiopathic Intracranial Hypertension: Evaluation Of Clinical Effectiveness And Cost Effectiveness
Funder: Department of Health and Social Care

Abstract: BACKGROUND_x000D_ _x000D_ WHAT IS IDIOPATHIC INTRACRANIAL HYPERTENSION (IIH)?_x000D_ A chronic condition of raised brain pressure occurring mainly in young obese women. Although relatively uncommon, the incidence is now rising rapidly in line with the obesity epidemic. Patients can suffer with headaches but the overwhelming issue is the risk of permanent blindness (25%)._x000D_ _x000D_ THE ISSUE?_x000D_ In patients with rapidly declining vision a surgical procedure is needed to reduce brain pressure (intracranial pressure or ICP) to try to prevent blindness. But there have been no clinical trial to determine the best surgical operation. _x000D_ The patient/physician priority setting partnership performed in 2019 highlighted that determining the best type of intervention to treat IIH was one of the top 10 most desired research questions for IIH. _x000D_ _x000D_ WHAT DO WE DO CURRENTLY?_x000D_ Usually, ICP can be quickly reduced by a surgical procedure called a Cerebrospinal Fluid (CSF) shunt. This involves a thin tube (shunt) being implanted in the brain. The excess CSF in the brain flows through the shunt to another part of the body, usually the abdomen. From here, it's absorbed into the blood. Low quality evidence has shown that it is effective at preventing blindness in most patients. However, within the first year after placement many shunts fail (e.g. get blocked or infected). This and other complications have a significant impact on patients and have important cost implications for the NHS. _x000D_ _x000D_ WHAT IS THE ALTERNATIVE?_x000D_ More recently, a procedure called Dural Vein Stenosis Stenting (DVSS) has been used. This involves a small tube (stent) placed across a narrowing (stenosis) of certain blood vessels in the brain. This improves blood flow and can lower ICP. So far, studies have not provided high quality evidence to show that this procedure can prevent blindness when vision is rapidly declining. Additionally, this procedure can also cause complications and require repeating._x000D_ These types of surgery have not been compared in an appropriately designed study._x000D_ _x000D_ THE PLAN?_x000D_ This trial will establish which of the surgical procedures is the best at saving vision, the safest with least complications and which is the most cost effective. _x000D_ _x000D_ THE SOLUTION?_x000D_ This research trial has been developed with input from IIH UK, the patient charity. We will ask patients who develop rapid deterioration of vision caused by IIH to participate. Participants will be allocated to CSF shunting or DVSS which will be decided at random by a computer. The main outcome to be evaluated will be preservation of vision. A number of key additional outcomes including treatment related complications, headache and patient reported quality of life, will also be assessed. An economic evaluation will be performed to estimate the cost-effectiveness of shunting versus DVSS._x000D_ We anticipate that 138 people will be required to take part in the study to answer this question with confidence. Participants will be asked to attend routine hospital check-up visits after the intervention for a period of 24 months. Their health would then be monitored through linked NHS database records for longer term follow up at 2 years and beyond _x000D_ There is a clear plan to share the results with relevant medical stakeholders including hospital doctors, GPs, professional societies, other patient support groups, and NHS policy makers. These will be published in major medical journals, and presented at international and national scientific meetings.

Lay abstract: Research question: What is the clinical and cost-effectiveness of dural vein stenosis stenting (DVSS) compared to cerebrospinal fluid (CSF) shunting in patients with idiopathic intracranial hypertension (IIH)?_x000D_ _x000D_ Background: IIH is a rare disease of unknown cause that typically affects young women. The incidence has increased by over 350% in the last decade. Morbidity in IIH is high due to the risk of visual loss (permanent in up to 25%) and chronic disabling headaches. Although the majority of patients can be managed conservatively, approximately 7% experience rapidly progressive loss of vision (termed fulminant IIH) and require emergency surgery to reduce intracranial pressure and preserve vision. Standard of care is CSF shunting, although complication rate is high, with up to 50% requiring revision within the first year. An alternative, DVSS, is cheaper, but to date there has been no randomised controlled trial to evaluate the safety and efficacy compared to CSF shunting._x000D_ _x000D_ Aims and objectives: Primarily to compare DVSS with CSF shunting in terms of visual field changes. In addition we aim to compare major intra-operative and post-operative complications; vision; headache; quality of life and the relative cost-effectiveness of the two approaches. The primary endpoint will be assessed at 12 months, but measures will also be assessed at 24 moths and longer term outcomes evaluated through NHS digital data._x000D_ _x000D_ Methods: A multicentre, open-label, randomised controlled trial with integrated health economic evaluation and an internal pilot with an embedded qualitative process evaluation. Patients with IIH and rapidly declining vision suitable for both intervention will be eligible. The intervention is DVSS and the comparator is CSF shunting._x000D_ _x000D_ Timelines for delivery: The trial will last for 66 months, incorporating 9 months for development of the trial infrastructure and a 10-month pilot phase with embedded qualitative process evaluation. The main trial will have a further 44-month time-frame for recruitment, randomisation and follow up. A further 3 months will be required for final patient follow-up data gathering, cleaning, analysis, and report preparation._x000D_ _x000D_ Anticipated impact and dissemination: If DVSS is non-inferior to CSF shunting in terms of visual field changes then major complications and which intervention enables a more rapid recovery, as well as being more cost-effective, is likely to be widely adopted for treatment of fulminant IIH. Positive outcomes will therefore benefit affected patients and the health service. If no benefit, or poorer outcomes are found, then where possible standard of care with CSF shunting will remain._x000D_ _x000D_ The results will be distributed to major stakeholders, including: patients, doctors, professional societies, patient support groups, trial networks and NHS policy makers. The findings will be published in major medical journals and presented in national and international scientific meetings. Findings will also be made available through links on the websites of health professional societies and the UK IIH charity.

Research activity codes: 6.3 MEDICAL DEVICES
Health categories: NEUROLOGICAL