Managing DME

Diabetic macular oedema enters new paradigm of individualised care

Dermot McGrath

Posted: Friday, March 1, 2019

Francesco Bandello speaking at the 18th EURETINA Congress in Vienna in 2018

Dramatic improvements in the diagnosis and treatment of diabetic macular oedema (DME) have ushered in a new era of patient management, according to Francesco Bandello MD, FEBO.

“There have been a number of important breakthroughs in DME over the past few years, with anti-VEGF treatments and multimodal imaging, among others, helping to transform the way we manage our patients. Treatment paradigms, aiming at multiple pathways, are now changing with respect to the past. Individualised therapy, where we choose the right therapy for the right patient, is the most effective approach to maximise results,” Dr Bandello told delegates attending the 18th EURETINA Congress in Vienna.

The classification of DME is critical to orient treatment choice, said Dr Bandello.

“We need to move away from reliance on the old classification system of identifying clinically significant macular oedema based on topography. This was fine when we had only laser treatments available. However, we can now use a more relevant and useful pathogenetic classification of DME,” he said.

Four distinct types of DME can be distinguished using fundus photography and spectral-domain optical coherence tomography (OCT): vasogenic, non-vasogenic, tractional DME and mixed DME, noted Dr Bandello.

Vasogenic DME, characterised by retinal thickening with vascular dilations, is the most frequent pattern. The non-vasogenic form involves retinal thickening without vascular dilations, while tractional DME typically involves central retinal thickness (CRT) of at least 400 microns with associated epiretinal traction. Mixed DME combines characteristics of two or more of these specific subtypes, explained Dr Bandello.

Fluorescein angiography (FA) should be used to identify microvascular abnormalities responsible for leakage and oedema, and to direct focal laser treatment with greater accuracy. Widefield FA is useful for locating peripheral ischaemia and is performed prior to initiation of therapy, he said.

Spectral domain OCT is important to assess the treatment response and to classify different types of oedema, said Dr Bandello. OCT angiography (OCT-A) is increasingly being used in a clinical setting and is useful for identifying foveal vascular enlargement, ischaemia, neovascularisation and the different vascular plexuses, he added.

“OCT-A enables closer observation of the blood flow of each retinal capillary layer and is the only instrument currently capable of visualising and quantifying what we are seeing in these areas,” said Dr Bandello.

Once diagnosis of DME has been confirmed, treatment should be planned according to DME subtype. Anti-VEGF agents are the current first-line therapy for both focal and diffuse DME, noted Dr Bandello, with two-year results from the Protocol T study showing bevacizumab, ranibizumab, and aflibercept all equally effective in restoring visual acuity. Bevacizumab was slightly less effective in patients whose baseline visual acuity was less than 20/350, he added.

While laser treatment has been supplanted as standard of care by anti-VEGF injections, it may still play a role in treating vasogenic DME, eyes affected by DME with CRT less than 300μm or eyes with persisting vitreomacular adhesion in the absence of response to intravitreal anti-VEGF or steroids, said Dr Bandello. Sub-threshold grid laser treatment may also be helpful in eyes with higher visual acuity affected by early diffuse DME.

Corticosteroids are a good second-line option for DME patients that do not respond to anti-VEGF therapy, or as a first-choice treatment for those with a history of a major cardiovascular event, or in vitrectomised or pseudophakic eyes.

“We must remember that 30-to-40% of our patients are not sensitive to anti-VEGF, so there is scope for using this kind of approach. Dexamethasone should be used first, with fluocinolone reserved for chronic macular oedema that is not responsive to other treatments,” he said.

Surgery, involving pars plana vitrectomy (PPV) and epiretinal membrane removal, also remains an option in cases of unresponsive tractional DME, noted Dr Bandello. PPV for tangential traction due to epiretinal or hyaloid membrane should be performed only if there is an incomplete response to anti-VEGF or dexamethasone.

Dr Bandello also emphasised the importance of a holistic approach to patient care, with close metabolic control of systemic disease.

“We need to ensure solid communication between diabetologist and retinologist, to ask for HbA1c levels and systemic blood pressure at baseline and at each follow-up,” he concluded.

Francesco Bandello:

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