Appropriate timing schedule for intravitreal anti-VEGF injection as adjuvant therapy before pars-plana vitrectomy in proliferative diabetic retinopathy, a meta analysis

ABSTRACT

Background

Many studies introduced intravitreal injections of anti-vascular endothelial growth factors (VEGFs) as a new strategy for safer and more convenient vitrectomy in patients with severe proliferative diabetic retinopathy (PDR). While possible side effects such as progression of vitreoretinal fibrosis should be kept in mind, these may be prevented by proper preoperative timing of injection.

Research design and methods

This study was conducted based on the systematic review guidelines in four steps: definition of search strategy, selecting and evaluating studies, checking inclusion and exclusion criteria, and statistical analysis. Eighteen clinical trials with a total sample size of 1165 patients were included. According to the timing of injection, patients were divided into three groups: injection 72 hours, injection 3–7 days, and injection 7–21 days before surgery.

Results

The lowest risk of intraoperative hemorrhage, the minimum duration of surgery and the lowest need for silicone oil (SO) tamponade was in the injection group 7–21 days before surgery. The rate of iatrogenic retinal break during surgery and the necessity for relaxing retinotomy in the injection group 72 hours before surgery was lower than the other two groups. However, there were limited data regarding the requirement of relaxing retinotomy, the need to inject SO, and the occurrence of iatrogenic retinal break.

Conclusions

This meta-analysis showed, to prevent tractional complications, it is recommended to inject within 3 days before surgery.

KEYWORDS:

• Diabetic retinopathy
• Proliferative diabetic retinopathy
• Vitrectomy
• Pars-plana vitrectomy
• PPV
• Anti-VEGF
• Vascular endothelial growth factor

Article highlights

• The epidemic of DM has become an emerging public health concern in recent years, and DR is the commonest cause of irreversible visual loss at a working age worldwide and PDR is the prevalent cause of blindness among these patients.

• Recently, many studies confirmed the effectiveness of preoperative intravitreal anti-VEGF therapy which is believed reduces many surgical procedures and complications, while possible side effects such as progression of vitreoretinal fibrosis should be kept in mind.

• This meta analysis showed that preoperative intravitreal VEGF inhibitors, reduce the surgical time, achieve fewer iatrogenic retinal breaks and subsequently reducing the need for SO tamponade, lessen intraoperative hemorrhage, and also lead fewer endodiathermy applications.

• This meta analysis showed improvement of clinical outcomes and reduction of complications in patients received adjuvant intravitreal Anti-VEGF 1-21 days before surgery. However, in order to prevent tractional complications, it is recommended to inject within 3 days before surgery.

Declaration of interest

The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.

Reviewer disclosures

Peer reviewers on this manuscript have no relevant financial or other relationships to disclose.

Additional information

Funding

This paper was not funded.