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Avastin before glaucoma valve surgery may ease postop medication burden
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Intravitreal bevacizumab injections before Ahmed glaucoma valve implantation reduced postoperative hyphema and the number of glaucoma medications in patients treated for neovascular glaucoma, according to a study.
Used as an adjunct to surgical procedures such as panretinal photocoagulation or drainage implantation, intravitreal Avastin (bevacizumab, Genentech) induces rapid regression of neovascularization after 1 week and reduces IOP, the study authors said.
In neovascular glaucoma, new vessels invade the anterior angle and form a fibrovascular membrane that blocks the trabecular meshwork and obstructs filtering of the aqueous humor, Marwan Sahyoun, MD, the corresponding author, said.
“The use of anti-angiogenic agents will inhibit the release of VEGF, which is supposed to prevent neovascularization of the iris and induce regression of the neovascular membrane. This will restore the trabecular meshwork patency and improve its filtration. In eyes with peripheral anterior synechiae, the effect of anti-VEGF on pressure can be due to reversible anatomic closure in angles that are still functional on a microscopic level,” Sahyoun told Ocular Surgery News.
Patients and methods
The retrospective institutional study, published in the Journal of Glaucoma, reviewed 39 eyes of 34 patients with neovascular glaucoma who underwent implantation of an Ahmed glaucoma valve (New World Medical).
The study included patients with elevated IOP that did not respond to medical treatment, photocoagulation or previous filtering surgery.
Patients younger than 18 years, those who underwent previous cyclodestructive procedures or received drainage implants, and those with less than 12 months of follow-up were excluded from analysis.
Neovascular glaucoma was defined as neovascularization of the iris and/or anterior chamber of the eye and/or iridocorneal angle observed on gonioscopy with IOP of 21 mm Hg or higher.
“The majority of our neovascular glaucoma cases, 87.2%, were secondary to diabetic retinopathy,” Sahyoun said. “Therefore, due to this high number, statistical analysis of etiologies’ impact on clinical outcomes was unfortunately impossible.”
All patients underwent panretinal photocoagulation before surgery.
Nineteen eyes received an intravitreal injection of bevacizumab 7 days preoperatively, and 20 eyes did not receive anti-VEGF therapy.
Investigators measured IOP and logMAR best corrected visual acuity preoperatively and 3 months, 6 months and 1 year, and subsequently every 6 months, after surgery. The number of glaucoma medications used by the patient was recorded preoperatively and 3 months, 6 months, 1 year and annually after surgery.
Mean follow-up was 37.13 months.
Surgical success was defined as stabilized IOP between 6 mm Hg and 21 mm Hg, without loss of light perception and with or without the use of glaucoma medications.
Surgical failure was defined as IOP of 21 mm Hg or more or 6 mm Hg or less at 2 consecutive follow-up visits, deterioration of BCVA with loss of light perception, or a need for additional surgical intervention.
Results and conclusions
IOP improved from 41.41 mm Hg preoperatively to 16.37 mm Hg at the last follow-up visit in the bevacizumab group and from 44.55 mm Hg to 20.05 mm Hg in the non-bevacizumab group.
The IOP reductions in each group were statistically significant, but the differences between the groups were not.
BCVA was 2.34 in the bevacizumab group and 2.66 in the non-bevacizumab group at final follow-up. The difference was not statistically significant, but there was a significant deterioration of BCVA in the control group.
“[Intravitreal bevacizumab] administration seems to prevent the deterioration of BCVA (P < .05), even though it does not play a role in the visual prognosis,” Sahyoun said.
The bevacizumab group had a significantly lower number of glaucoma medications, 0.74, at the last visit compared with 1.30 medications in the non-bevacizumab group. The between-group difference was statistically significant (P = .02).
The bevacizumab group had significantly less hyphema than the non-bevacizumab group (P = .02).
The probability of success was 63.2% in the bevacizumab group and 70% in the control group; the between-group difference was not statistically significant.
“We unfortunately did not study factors that determine probability of success, as this was not fixed as a primary objective. However, in a current study that we recently conducted in our center, we found that an initial BCVA of 2 logMAR or less and a history of high blood pressure were two independent factors associated with a significantly higher Ahmed glaucoma valve success rate,” Sahyoun said. – by Matt Hasson and Kristie L. Kahl
- Reference:
- Sahyoun M, et al. J Glaucoma. 2015;doi:10.1097/IJG.0000000000000234.
- For more information:
- Marwan Sahyoun, MD, can be reached at Eye and Ear Hospital International, Saint Vincent Street, Naccache, Dbayeh 70-933, Lebanon; email: mar1.sahyoun@gmail.com.
Disclosure: Sahyoun reports no relevant financial disclosures.