Arteriovenous crossing sheathotomy for branch retinal vein occlusion (interventional procedures consultation)

NATIONAL INSTITUTE FOR HEALTH AND CLINICAL EXCELLENCE

Interventional procedure consultation document

Arteriovenous crossing sheathotomy for branch retinal vein occlusion

Branch retinal vein occlusion (BRVO) is a blockage in a branch retinal vein of the eye and is usually associated with high blood pressure. Ageing and raised blood pressure can cause the artery wall to harden and thicken, which can compress the retinal vein with which it shares a common sheath. This obstructs blood flow in the vein at the point of compression, and may lead to the vein being completely blocked.

In an arteriovenous crossing sheathotomy, the artery and the vein are separated from each other using a very small blade to cut away the sheath that they share. The aim of the procedure is to improve blood flow in the vein, reduce surrounding swelling (oedema) and improve sight.

 

The National Institute for Health and Clinical Excellence (NICE) is examining arteriovenous crossing sheathotomy for branch retinal vein occlusion and will publish guidance on its safety and efficacy to the NHS in England, Wales, Scotland and Northern Ireland. NICE’s Interventional Procedures Advisory Committee has considered the available evidence and the views of Specialist Advisers, who are consultants with knowledge of the procedure. The Advisory Committee has made provisional recommendations about arteriovenous crossing sheathotomy for branch retinal vein occlusion.

This document summarises the procedure and sets out the provisional recommendations made by the Advisory Committee. It has been prepared for public consultation. The Advisory Committee particularly welcomes:

  • comments on the provisional recommendations
  • the identification of factual inaccuracies
  • additional relevant evidence, with bibliographic references where possible.

Note that this document is not NICE’s formal guidance on this procedure. The recommendations are provisional and may change after consultation.

The process that NICE will follow after the consultation period ends is as follows.

  • The Advisory Committee will meet again to consider the original evidence and its provisional recommendations in the light of the comments received during consultation.
  • The Advisory Committee will then prepare draft guidance which will be the basis for NICE’s guidance on the use of the procedure in the NHS in England, Wales, Scotland and Northern Ireland.

For further details, see the Interventional Procedures Programme manual, which is available from the NICE website (www.nice.org.uk/ipprogrammemanual).

NICE is committed to promoting through its guidance race and disability equality and equality between men and women, and to eliminating all forms of discrimination. One of the ways we do this is by trying to involve as wide a range of people and interest groups as possible in the development of our guidance on interventional procedures. In particular, we aim to encourage people and organisations from groups in the population who might not normally comment on our guidance to do so. We also ask consultees to highlight any ways in which draft guidance fails to promote equality or tackle discrimination and give suggestions for how it might be improved. NICE reserves the right to summarise and edit comments received during consultations, or not to publish them at all, where in the reasonable opinion of NICE, the comments are voluminous, publication would be unlawful or publication would otherwise be inappropriate.

Closing date for comments: 21 December 2009

Target date for publication of guidance: March 2010

 

1       Provisional recommendations

1.1  Current evidence on the efficacy and safety of arteriovenous crossing sheathotomy for branch retinal vein occlusion (BRVO) is inadequate in quantity and quality. In particular, there is a concern that sheathotomy used in combination with vitrectomy may confer additional risks without evidence of additional benefit. Therefore, this procedure should only be used in the context of research.

1.2  Research should take the form of controlled trials and should clearly define patient selection, the timing of treatment in relation to venous occlusion, and details of other treatment modalities used. NICE may review the procedure upon publication of further evidence.

2       The procedure

2.1    Indications and current treatments

2.1.1  Branch retinal vein occlusions typically occur at arteriovenous crossings, where the artery and vein share a common membranous sheath. Degenerative changes may cause hardening of the retinal arteries which may lead to compression of companion retinal veins. This compression obstructs blood flow in the vein, leading to thrombosis, macular oedema and decreased visual acuity.

2.1.2  The natural history of BRVO is variable. It is usually managed by observation, and decisions to use further interventions are based on several factors, including the development of neovascularisation and the persistence of macular oedema and reduced visual acuity. Current treatments include grid laser photocoagulation of the macula, intravitreal injection of triamcinolone or an anti-vascular endothelial growth factor agent, or surgery in the form of plana vitrectomy (surgical removal of the vitreous) without sheathotomy.

2.2    Outline of the procedure

2.2.1  Arteriovenous crossing sheathotomy for BRVO involves cutting the sheath surrounding the artery and the vein and separating them at the site where they cross, with the aim of restoring venous drainage.

2.2.2  The procedure may be carried out with the patient under general or local anaesthesia. A pars plana vitrectomy is usually performed before identification of the affected arteriovenous crossing and incision of the membranous sheath. A blade is used to separate adhesions holding the artery to the vein and the artery is then lifted away from the vein.

Sections 2.3 and 2.4 describe efficacy and safety outcomes from the published literature that the Committee considered as part of the evidence about this procedure. For more detailed information on the evidence, see the overview, available at www.nice.org.uk/IP222aoverview.

 

2.3    Efficacy

2.3.1  In a randomised controlled trial (RCT) of 40 patients treated by intravitreal injection or sheathotomy, mean improvement in best corrected visual acuity (BCVA) score (measured on the early treatment diabetic retinopathy study scores chart by the number of letters patients could read from the chart, with correction for individual refractive errors) was greater in the intravitreal injection group (12.2 ± 12.3) than in the sheathotomy group (4.4 ± 8.9) at 1-month follow-up (p = 0.026). Improvements in outcome scores were not significantly different between the groups at any other follow-up interval, up to 6 months. An RCT of 36 patients treated by sheathotomy or vitrectomy reported that both groups showed significant improvement in BCVA from baseline, but there was no significant difference between the groups at 31-month follow-up (0.014 logMAR and 0.08 logMAR, respectively) (p = 0.25).

2.3.2  A non-randomised controlled study of 68 patients reported no significant difference in mean BCVA between patients in the sheathotomy group (improvement to 0.35) and those who declined surgery (deterioration to 0.22) at 6-week follow-up (significance not stated).

2.3.3  A non-randomised controlled study of 40 patients reported that the mean number of lines of BCVA gained at 14-month follow-up in patients treated by sheathotomy (4.55 lines) was significantly greater than in patients in the control group who were followed up to 19 months (either no surgery or grid laser photocoagulation) (1.55 lines) (p = 0.023).

2.3.4  A non-randomised controlled study of 36 patients reported that there was no significant difference in the mean change in BCVA from baseline in the sheathotomy group (0.29 logMAR ± 0.35) compared with the group who had vitrectomy alone (0.30 logMAR ± 0.22) at 1-year follow-up (p = 0.71).

2.3.5  A case series of 60 patients treated with sheathotomy for BRVO with macular oedema reported recurrence of macular oedema in 3% (2/60) of patients at 12- to 16-month follow-up.

2.3.6  The Specialist Advisers listed key efficacy outcomes as improved blood flow (on fluorescein angiography), resolution of macular oedema and/or reduced macular thickness, and improvement in BCVA.

2.4    Safety

2.4.1  An intraoperative peripheral retinal tear (successfully treated by laser coagulation and fluid–air exchange) was reported in 5% (1/20) of patients in the sheathotomy group of the non-randomised controlled study of 36 patients.

2.4.2  Intraoperative haemorrhage caused by retinal vascular damage (controlled by increasing intraocular pressure by high pressure perfusion) was reported in the sheathotomy group of the RCT of 36 patients. Vitreous haemorrhage which resolved spontaneously was reported in 10% (2/20) of patients in the sheathotomy group of the non-randomised controlled study of 36 patients (timing of event and follow-up not stated).

2.4.3  Cataract development was reported in 15% (3/20) of patients in the non-randomised controlled study of 40 patients (sheathotomy group); and in 10% (2/20) of patients in the sheathotomy group compared with 6% (1/16) of patients in the vitrectomy group of the non-randomised controlled study of 36 patients (significance and follow-ups not stated). The RCT of 40 patients reported that the mean increase in grade of cataracts was not significantly different between patients treated by sheathotomy or by intravitreal injection (p = 0.382) (absolute figures and length of follow-up not stated).

2.4.4  The non-randomised controlled study of 68 patients reported that 2% (1/43) of patients in the sheathotomy group and 36%(9/25) of patients in the no surgery group lost 2 or more BCVA lines at 6-week follow-up.

2.4.5  The Specialist Advisers listed adverse events reported in the literature as arterial or venous haemorrhage, vitreous haemorrhage, cataract development and retinal detachment. They listed recurrent BRVO as an anecdotal adverse event and considered theoretical adverse events to include endophthalmitis and/or ophthalmitis, or glaucoma.

3     Further information

3.1  This document is a review of NICE interventional procedures guidance 72, published in 2004.

Bruce Campbell
Chairman, Interventional Procedures Advisory Committee
November 2009

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 It is the responsibility of consultees to accurately cite academic work in order that they can be validated.

This page was last updated: 19 August 2015