Intraprocedural OCT monitoring of the immediate treatment response during indocyanine green angiography-guided laser therapy of teleangiectatic capillaries in diabetic macular edema

Microaneurysm detection using high-speed megahertz optical coherence tomography angiography in advanced diabetic retinopathy

PURPOSE

To compare detection rates of microaneurysms (MAs) on high-speed megahertz optical coherence tomography angiography (MHz-OCTA), fluorescein angiography (FA) and colour fundus photography (CF) in patients with diabetic retinopathy (DR).

METHODS

For this exploratory cross-sectional study, MHz-OCTA data were acquired with a swept-source OCT prototype (A-scan rate: 1.7 MHz), and FA and CF imaging was performed using Optos® California. MA count was manually evaluated on en face MHz-OCTA/FA/CF images within an extended ETDRS grid. Detectability of MAs visible on FA images was evaluated on corresponding MHz-OCTA and CF images. MA distribution and leakage were correlated with detectability on OCTA and CF imaging.

RESULTS

47 eyes with severe DR (n = 12) and proliferative DR (n = 35) were included. MHz-OCTA and CF imaging detected on average 56% and 36% of MAs, respectively. MHz-OCTA detection rate was significantly higher than CF (p < 0.01). The combination of MHz-OCTA and CF leads to an increased detection rate of 70%. There was no statistically significant association between leakage and MA detectability on OCTA (p = 0.13). For CF, the odds of detecting leaking MAs were significantly lower than non-leaking MAs (p = 0.012). Using MHz-OCTA, detection of MAs outside the ETDRS grid was less likely than MAs located within the ETDRS grid (outer ring, p < 0.01; inner ring, p = 0.028). No statistically significant difference between rings was observed for CF measurements.

CONCLUSIONS

More MAs were detected on MHz-OCTA than on CF imaging. Detection rate was lower for MAs located outside the macular region with MHz-OCTA and for leaking MAs with CF imaging. Combining both non-invasive modalities can improve MA detection.

Photocoagulation or sham laser in addition to conventional anti-VEGF therapy in macular edema associated with TelCaps due to diabetic macular edema or retinal vein occlusion (TalaDME): a study protocol for a multicentric, French, two-group, non-commercial, active-control, observer-masked, non-inferiority, randomized controlled clinical trial

BACKGROUND

Macular edema (ME) results from hyperpermeability of retinal vessels, leading to chronic extravasation of plasma components into the retina and hence potentially severe visual acuity loss. Current standard of care consists in using intravitreal injections (IVI), which results in a significant medical and economic burden. During diabetic retinopathy (DR) or retinal vein occlusion (RVO), it has recently been shown that focal vascular anomalies (capillary macro-aneurysms, also termed TelCaps) for telangiectatic capillaries may play a central role in the onset, early recurrence, and/or persistence of ME. Since targeted photocoagulation of TelCaps may improve vision, identification, and photocoagulation of TelCaps, it may represent a way to improve management of ME.

OBJECTIVE

The Targeted Laser in (Diabetic) Macular Edema (TalaDME) study aims to evaluate whether ICG-guided targeted laser (IGTL), in association with standard of care by IVI, allows reducing the number of injections during the first year of treatment compared with IVI only, while remaining non-inferior for visual acuity.

METHODS

TalaDME is a French, multicentric, two-arms, randomized, sham laser-controlled, double-masked trial evaluating the effect of photocoagulation of TelCaps combined to IVI in patients with ME associated with TelCaps. Patients with vision loss related to center involved ME secondary to RVO or DR and presenting TelCaps are eligible. Two hundred and seventy eyes of 270 patients are randomized in a 1:1 ratio to standard care, i.e., IVI of anti-VEGF solely (control group) or combined with IGTL therapy (experimental group). Stratification is done on the cause of ME (i.e., RVO versus diabetes). Anti-VEGF IVI are administered to both groups monthly for 3 months (loading dose) and then with a pro re nata regimen with a monthly follow-up for 12 months. The primary endpoint will be the number of IVI and the change in visual acuity from baseline to 12 months. Secondary endpoints will be the changes in central macular thickness, impact on quality of life, cost of treatment, and incremental cost-utility ratio in each groups.

KEY SAFETY

Rare but severe AE linked to the use of IVI and laser, and previously described, are expected. In the sham group, rescue laser photocoagulation may be administered by the unmasked investigator if deemed necessary at month 3.

DISCUSSION

The best management of ME associated with TelCaps is debated, and there have been no randomized study designed to answer this question. Given the fact that TelCaps may affect 30 to 60% of patients with chronic ME due to DR or RVO, a large number of patients could benefit from a specific management of TelCaps. TalaDME aims to establish the clinical and medico-economic benefits of additional targeted laser. The results of TalaDME may raise new recommendations for managing ME and impact healthcare costs.

TRIAL REGISTRATION

EudraCT: 2018-A00800-55/ NCT03751501. Registration date: Nov. 23, 2018.

Laser-Induced Blood Coagulation for Surgical Application: A Scoping Review

There is a lack of evidence-based reviews on the effects of laser irradiation on blood coagulation in the literature, despite a large number of clinical trials. We therefore evaluated the available evidence on laser irradiation parameters used in coagulation of blood to optimize physical parameters. We performed a literature search for recent scientific studies indexed between 2017 and 2023 using the databases of PubMed and ScienceDirect. Articles were selected based on defined inclusion and exclusion criteria, and 78 publications in total were eventually included in this scoping review. The following were found to produce significant benefits in blood coagulation for surgical application: (1) dentistry and oral surgeries: 980 nm, 27 s, 2 W, 1502.7 W/cm2, 26.5 J, 622 J/cm2, 400 μm; (2) urogenital disorders: 532 nm, 4 s, 40 W, 10600 W/cm2, 1.3 J, 424 J/cm2, 600 μm; (3) ophthalmic disorders: 810 nm, 1 s, 1 W, 3540 W/cm2, 0.75 J, 1326 J/cm2, 100 μm; (4) embryological surgeries: 1064 nm, 10 s, 25 W, 35400 W/cm2, 262.5 J, 371000 J/cm2, 332.5 μm; (5) dermatological disorders: 1064 nm, 20 W, 2440 W/cm2, 0.1 J, 24 J/cm2, 670 μm; (6) gastrointestinal disorders: 532 nm, 3 s, 20 W, 1051 W/cm2, 120 J, 26500 J/cm2, 760 μm; (7) neurological surgeries: 2.5 s, 1.5 W, 1035 W/cm2, 2 J, 1584 J/cm2, 385 μm; (8) pulmonary disorders: 1320 nm, 5s, 35 W, 12450 W/cm2, 250 J, 65000 J/cm2, 700 μm (9) cardiovascular disorders: 1064 nm, 16.5 s, 5 W, 1980.5 W/cm2, 900 J, 760 J/cm2, 400 μm. In conclusion, our scoping review identifies that combining data from all clinically heterogeneous studies suggests that laser irradiation reflects an effective method for inducing blood coagulation in several medical fields.

The Role of Laser Photocoagulation in Treating Diabetic Macular Edema in the Era of Intravitreal Drug Administration: A Descriptive Review

Background and Objectives: This study aimed to elucidate the role of laser photocoagulation therapy in the treatment of diabetic macular edema (DME) as an alternative to, or in conjunction with, the first-line treatment, anti-vascular endothelial growth factor (VEGF). Materials and Methods: A comprehensive literature search to identify studies that evaluated the efficacy of laser photocoagulation therapy in the management of DME was performed. The relevant findings of the efficacy of focal/grid laser therapy from data in randomized, controlled trials were synthesized, and the potential of new laser technologies, such as navigated laser systems, pattern scan lasers, and subthreshold lasers, was explored. The usefulness of multimodal imaging-guided laser therapy was also evaluated, with a focus on the potential contribution to anti-VEGF therapy. Results: Focal laser photocoagulation targeting microaneurysms remains an effective therapeutic approach to chronic refractory edema, despite the widespread use of anti-VEGF therapy. To achieve the best possible treatment outcomes, precise identification of microaneurysms is essential. This requires the use of multimodal imaging-guided, highly accurate, minimally invasive coagulation techniques. Subthreshold laser therapy can also reduce the frequency of anti-VEGF injections and minimize treatment burden. Conclusions: Further studies are needed to determine the optimal timing and settings for laser photocoagulation therapy and the potential of new laser technologies in the management of DME. Nevertheless, laser photocoagulation therapy plays an important role in the management of DME, in conjunction with anti-VEGF therapy.

Focal Photocoagulation as an Adjunctive Therapy to Reduce the Burden of Intravitreal Injections in Macula Edema Patients, the LyoMAC2 Study

AIM

To assess the efficacy of focal photocoagulation of capillary macroaneurysms (CMA) to reduce the burden of intravitreal injections (IVI) in patients with macular edema (ME).

MATERIALS AND METHODS

Retrospective multicenter study in patients with diabetic ME or ME secondary to retinal vein occlusion (ME-RVO). CMA associated with ME were selectively photocoagulated. Patients were followed for one year after photocoagulation.

RESULTS

93 eyes of 76 patients were included in this study. At 6 months after the laser (n = 93), there was a significant decrease in mean macular thickness (from 354 µm to 314 µm, p < 0.001) and in mean IVI number (from 2.52 to 1.52 at 6 months, p < 0.001). The mean BCVA remained stable (0.32 and 0.31 logMAR at baseline and 6 months, p = 0.95). At 12 months (n = 81/93), there was a significant decrease in mean macular thickness (from 354 µm to 314 µm, p < 0.001) and in mean IVI number (from 4.44 to 2.95 at 12 months, p < 0.001), while the mean BCVA remained stable (0.32 and 0.30 logMAR at baseline and 12 months, p = 0.16).

CONCLUSION

Focal laser photocoagulation of CMA seems to be effective and safe for reducing the burden of IVI in patients with ME. Their screening during the follow-up should be considered closely.