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Although visual results after use of the new surgical method of retinal endovascular lysis (REVL) seem encouraging,1,2 its effectiveness has not been proved in a controlled, prospective clinical trial. From a histological postmortem study of eyes with central retinal vein occlusion (CRVO), it is still questionable whether an older thrombus can be dissolved using recombinant tissue plasminogen activator (rt‐PA).3 We report on the histopathological findings in a human eye 9 months after REVL.
We report the case of a 62‐year‐old woman having a 7‐week‐old, highly ischaemic CRVO in her left eye with hand movement vision. Although we were concerned about treating an older thrombus with rt‐PA, we were interested in seeing whether thrombolysis has the potential to prevent neovascular glaucoma, for example, by minimising capillary nonperfusion. We attempted an REVL to improve retinal blood flow. The procedure was approved by our local ethics committee.
After a standard vitrectomy with detachment of the posterior hyaloid, the vessel wall was pierced with a glass cannula (Micron Ophthalmic, Margate, Florida, USA) as described by Weiss et al,2 and 1 ml (200 μg/ml) rt‐PA was injected successfully (fig 11).). Formation of an epiretinal membrane at the injection site could be detected 3 weeks postoperatively. Angiographic examination 3 days postoperatively did not show improved arteriovenous passage time. In addition, the patient's postoperative vision did not change, and despite intensive photocoagulation and cryotherapy in the early postoperative period, the globe had to be removed 9 months later because of painful phthisis.
The entire specimen was immersed for light microscopy. Gross findings included numerous haemorrhages scattered throughout the retina. Histological examination confirmed the diagnosis of a CRVO with subretinal fluid, preretinal haemorrhage, optic atrophy and loss of ganglion cells. Unfortunately, we could not detect the thrombus histologically.
In the surgically treated area of the retina, we found a thickened venous wall due to the longstanding occlusion. The internal limiting membrane was interrupted and the vessel wall was in contact with an epiretinal membrane (fig 22).
This is the first case to show the histological changes after surgical REVL in a human eye.
In other patients, we could not be certain whether the intravenous injection had succeeded using this sophisticated surgical method. Beyond the expected histological findings after CRVO without a thrombus but typical fluorescein angiography in this case, we could identify the injection site histologically and confirm that the vein had been successfully punctured.
In this case, REVL did not prevent neovascular glaucoma despite successful rt‐PA injection in a venous branch close to the papilla. Clinical, histological and angiographic findings suggest that the occlusion was not influenced by the injection and we conclude that rt‐PA injection after 7 weeks of CRVO is too late.
Competing interests: None.
The necessary ethics committee approval was secured for this study from the ethics committee of the University of Freiburg, Elsaesser Strasse 2m, Haus 1A, D‐79110 Freiburg, Germany.