The use of intravitreal tissue plasminogen activator in the treatment of experimental subretinal hemorrhage in the pig model.
OBJECTIVE
To clinically and surgically evaluate clot lysis in an animal model of subretinal hemorrhage after intravitreal injection of tissue plasminogen activator.


METHODS
Autologous subretinal hemorrhages were created via a transvitreal approach in 18 pigs. The next day (day 1) animals were randomly selected to receive either an intravitreal injection of 0.1 mL balanced salt solution or 0.1 mL tissue plasminogen activator (25 micrograms) followed by observation or vitrectomy a day later. On day 2, six pigs (all treated with tissue plasminogen activator) underwent a vitrectomy in which aspiration of the subretinal hemorrhage was attempted. The other eyes were evaluated for clot lysis by ophthalmoscopy at days 3, 10, and 30. All eyes were examined histopathologically.


RESULTS
The eyes that had been treated with tissue plasminogen activator demonstrated a color change at the peripheral margin, which suggested that clot lysis had occurred. At the time of the vitrectomy, the clots were liquefied partially; removal by aspiration alone, however, was not possible. Photoreceptor damage was moderate to severe by day 10 in all eyes, whether they were treated with tissue plasminogen activator or balanced salt solution. All eyes that underwent vitrectomy had moderate to severe photoreceptor damage.


CONCLUSIONS
In this animal model, intravitreal tissue plasminogen activator was associated with features that suggested partial clot lysis; tissue plasminogen activator did not produce sufficient lysis to allow surgical removal by aspiration alone, however.
Boone
D E
DE
Department of Ophthalmology, University of Iowa Hospitals and Clinics, Iowa City 52242, USA.
Boldt
H C
HC
Ross
R D
RD
Folk
J C
JC
Kimura
A E
AE
D000818:Animals; D004195:Disease Models, Animal; D010786:Photoreceptor Cells / Q000473:pathology; D010960:Plasminogen Activators / Q000627:therapeutic use*; D011897:Random Allocation; D011994:Recombinant Proteins; D012166:Retinal Hemorrhage / Q000188:drug therapy* / Q000473:pathology; D013552:Swine; D015912:Thrombolytic Therapy; D010959:Tissue Plasminogen Activator / Q000627:therapeutic use*; D014821:Vitrectomy; D014822:Vitreous Body
D011994:Recombinant Proteins; D010960:Plasminogen Activators; D010959:Tissue Plasminogen Activator