Intra-retinal Arterial Cannulation using a Microneedle for Central Retinal Artery Occlusion

Abstract

Central retinal artery occlusion (CRAO) is a severe disease, often causing blindness. We evaluated the efficacy and safety of a surgical procedure for the treatment of acute CRAO in which retinal arterial cannulation with tissue plasminogen activator (tPA) is performed. The surgical procedure consisted of vitrectomy followed by cannulation of the central retinal artery and injection of tPA (200 μg) using a 47-gauge microneedle. Thirteen CRAO patients were treated within 48 hours of the onset of symptoms. The central retinal artery of all 13 eyes was successfully cannulated. The mean interval between the onset of symptoms and surgery was 38.7 hours. The results for all 13 eyes treated showed a statistically significant improvement in mean visual acuity between before and one month after treatment (-1.60 vs. -0.82 logarithmic values for minimum angle resolution (LogMAR), p = 0.0021). Fluorescein angiography showed complete reperfusion and incomplete reperfusion in 10 eyes and 3 eyes, respectively. Recently developed surgical instruments have made retinal-arterial cannulation feasible. Intra-retinal-arterial cannulation has potential as a method of improving visual function and microcirculation in eyes affected by CRAO.

Figure 1

Surgical procedure for retinal-arterial fibrinolysis to treat eyes with central retinal arterial occlusion with a microneedle. The outer diameter of the microneedle is 50 micrometers although it appears larger in the intraoperative photograph due to perspective. It is held in the right hand and inserted into the central retinal artery while holding a soft-tip needle in the left hand to stop any bleeding (A). Tissue plasminogen activator solution is injected into the vessel through the microneedle (B). The arterial vessel turns white in response to the pressure of injected solution (C). The solution is injected over a 3-minute period, and the needle is removed gently (D).

Figure 2

Change in visual acuity before and one month after surgery. Visual acuity improved in 12 of 13 eyes (91%) after surgery more than 0.3 LogMAR. LogMAR = logarithm of the minimum angle of resolution.

Figure 3

Fluorescein angiography images before and 3 days after cannulation in a patient with CRAO studied. Preoperative visual acuity was counting fingers. None of the arterial vessels filled with dye in the early phase (30 seconds) (Upper left). Even in the late phase (10:59 seconds), some of the arterial vessels had not completely filled with the dye (Upper right). All vessels were much more filled with dye, with one–third air after cannulation in early phase (31 seconds) (Lower left). All of vessels, including the peripheral vessels, are seen clearly in the late phase (4:59 seconds) (Lower right).

Figure 4

Fundus photographs and optical coherent tomography images before and 3 days after surgery in a patient shown in Fig. 3. A cherry-red spot, narrowed arterial vessels, and mild macular edema are seen and OCT showed thickened inner retinal layer. There was evidence of middle retinal infarction seen, particularly in eyes with incomplete CRAO (Left). Visual acuity was counting fingers. Three days after cannulation, the mild cherry-red spot and clearer retinal vessels are seen with one-third air injected during surgery and OCT showed normal inner retinal layer (Right). Visual acuity was improved 20/400 1 week after surgery.

Figure 5

Visual field for this patient one month after surgery. Visual field before cannulation was severely limited. A Goldman visual field examination post-surgery demonstrated much improved visual field, though some relative central scotoma remains.