Bevacizumab and Long Acting Gas in Diabetic Vitrectomy
Status:
Completed
Trial end date:
2008-02-01
Target enrollment:
Participant gender:
Summary
Persistent or recurrent vitreous hemorrhage after vitrectomy for diabetic retinopathy
complications is a common occurrence with an incidence of 12% to 63%. This complication may
prolong vitreous clear-up and delay visual rehabilitation significantly, and sometimes
requires additional procedures or surgery.
The causes of bleeding are diverse. Evidence suggests fibrovascular proliferation from the
sclerotomy sites or from the vitreous base may be an important source of recurrent vitreous
hemorrhage; other sources of bleeding include iatrogenic intraoperative injury of retinal
vessels, and incomplete removal of fibrovascular tissues.
We have reported on the possible benefit of peripheral retinal cryotherapy and cryotherapy
treatment of sclerotomy sites to prevent delayed-onset recurrent vitreous hemorrhage, and the
possible benefit of intravitreal long-acting gas to reduce the occurrence of early
postoperative recurrent vitreous hemorrhage, especially for cases with active fibrovascular
proliferation. However, minor recurrent vitreous hemorrhage and prolonged reabsorption of
lysed blood clots from surgical trauma remain important factors to cause media opacity long
enough to prevent quick visual rehabilitation.
Intravitreal bevacizumab has been noted to induce rapid regression of retinal and iris
neovascularization in proliferative diabetic retinopathy. Further, presurgical administration
of intravitreal bevacizumab may reduce intraoperative bleeding during membrane dissection in
PDR with traction retinal detachment. We hypothesize that presurgical treatment of
intravitreal bevacizumab may reduce intraoperative bleeding and the amount of residual blood
clots, while intraoperative infusion of long-acting gas may facilitate post-operative
recovery of surgically injured retinal vessels. These combined effects would thus enhance
early clear-up of vitreous opacity from clot lysis and recurrent retinal bleeding. To
investigate this hypothesis, a clinical prospective study was undertaken to evaluate the
effects of bevacizumab pretreatment combined with intravitreal infusion of long-acting gas on
the clearance speed and the recurrence rate of early postoperative vitreous hemorrhage in
vitrectomy for active diabetic fibrovascular proliferation.