Session Title: Free Paper Session 24: Vascular Diseases & Diabetic Retinopathy VII
Session Date/Time: Sunday 10/09/2017 | 10:00-11:30
Paper Time: 10:06
Venue: Room 117
First Author: : I.McAllister AUSTRALIA
Co Author(s): : L. Smithies P. Sanfilippo
To assess the efficacy and safety of a combined treatment for patients with macular oedema from central retinal vein occlusion (CRVO) consisting of intravitreal ranibizumab and a laser induced chorioretinal anastomosis (L-CRA) compared to ranibizumab alone. The primary endpoint was the number of ranibizumab injections required in the prn retreatment phase from months 7 -24. Secondary endpoints included best corrected visual acuity (BCVA) and central foveal thickness (CFT).
24 month randomised, partially masked study conducted in Australia consisting of 58 patients with macular oedema secondary to CRVO of less than 9 months duration, BCVA of 24-73 letters on an early treatment of diabetic retinopathy chart, and CFT of greater than 250um.
58 patients with CRVO were randomized 1:1 to receive either a sham L-CRA plus intravitreal ranibizumab 0.5mg (29 patients) or L-CRA plus ranibizumab 0.5mg (29 patients). Selection criteria and the retreatment protocol were based on the CRUISE study of ranibizumab for CRVO. The L-CRA/sham was attempted at 2 sites at baseline above, and below the optic disc. Monthly injections of ranibizumab in both groups were commenced at month 1 and continued as per the CRUISE study for the next 6 months. From month 7-24 both groups received monthly prn ranibizumab as required according to the retreatment protocol. The 24 month analysis was conducted following the intent-to-treat principle on the full analysis set, with the last observation carried forward for missing data. Outcome measures included change from baseline BCVA and CFT, both measured by masked assessors and also the number of injections required in the prn phase according to predetermined reinjection criteria.
Patients were evenly matched for age, CRVO duration, BCVA and CFT between the 2 groups. A successful L-CRA was created in at least one site in 24 of 29 patients in the combination group (82.8%) (17 patients with 2 sites, 7 patients with 1 site). The mean number of injections required in the prn phase from month 13 -24 was 7.0 for the ranibizumab alone group vs 3.2 for the ranibizumab/total L-CRA (p<0.001). For the subgroup of ranibizumab/functioning L-CRA the injections decreased to 2.2 (p<0.001). The difference in mean BCVA from baseline to month 24 for was an increase of 10.3 letters for the ranibizumab/total L-CRA compared to the ranibizumab alone group (p=0.04) and 15.0 letters for the ranibizumab/functioning L-CRA group (p=0.001). There was no significant difference in CFT between the treatment groups. Of the potential 58 sites small new vessel development was seen at 10 sites (17%), 5 of which regressed spontaneously and the remaining 5 were treated with sectorial laser peripheral to the L-CRA site. 3 patients (10.3%) developed minor macular traction from avascular fibrous tissue proliferation treated with a vitrectomy as per protocol. No patient developed significant retino-choroidal neovascularization requiring vitrectomy surgery.
For CRVO the combination of an L-CRA which addresses the elevation in venous hydrostatic pressure seen in this condition, to the current conventional treatment with intravitreal ranibizumab, results in improved visual acuity outcomes and lessens the need for repeated injections for patients with this condition. Over an 18 month follow-up period of prn treatment the injections required decreased from 7.0 for those treated with ranibizumab alone to 3.2 for the group treated with the combined therapy (p<0.001). Visual acuity improvement was 10.3 letters greater in the combined treatment group (p=0.04) at the study conclusion. The procedure is associated with a risk of fibrous proliferation and new vessel formation however this is manageable with careful follow-up and prompt treatment.