Evaluation of success after second Ahmed glaucoma valve implantation

Abstract

Purpose:To evaluate the outcome of the second Ahmed glaucoma valve (AGV) surgery in eyes with failed previous AGV surgery.Design:Retrospective case series.Patients and Methods:Following chart review, 36 eyes of 34 patients with second AGV implantation were enrolled in this study. The primary outcome measure was surgical success defined in terms of intraocular pressure (IOP) control using two criteria: Success was defined as IOP ≤21 mmHg (criterion 1) and IOP ≤16 mmHg (criterion 2), with at least 20% reduction in IOP, either with no medication (complete success) or with no more than two medications (qualified success). Kaplan–Meier survival analysis was used to determine the probability of surgical success.Results:The average age of the patients was 32.7 years (range 4–65), and the mean duration of follow-up was 21.4 months (range 6–96). Preoperatively, the mean IOP was 26.94 mmHg (standard deviation [SD] 7.03), and the patients were using 2.8 glaucoma medications on average (SD 0.9). The mean IOP decreased significantly to 13.28 mmHg (SD 3.59) at the last postoperative visit (P = 0.00) while the patients needed even fewer glaucoma medications on average (1.4 ± 1.1, P = 0.00). Surgical success of second glaucoma drainage devices (Kaplan–Meier analysis), according to criterion 1, at 6, 12, 18, and 42 months was 94%, 85%, 80%, and 53% respectively, and according to criterion 2, was 94%, 85%, 75%, and 45%, respectively.Conclusion:Repeated AGV implantation seems to be a safe modality of treatment with acceptable success rate in cases with failed previous AGV surgery.

Safety and Efficacy of Second Ahmed Valve Implant in Refractory Glaucoma

“…For these reasons, in both centers, devices with flow-restricting technology have been preferred. In terms of efficacy, our results are in line with those already published in the literature [19][20][21][22][23][24][25][26][27][28]. The success rate reported in a recent metanalysis of Yoon et al [29] ranged between 37% to 83% at three years with a significant reduction in glaucoma medications.…”

Surgical Outcomes of a Second Ahmed Glaucoma Valve Implantation in Asian Eyes with Refractory Glaucoma

“…ese studies were not carried out in Asian countries, with the exception of one, Ko et al in Korea. ey reported similar success rates ranging from 62.9% to 87.0% at one year, 56.6% to 80.0% at two years, and 52.0% to 57.0% at three years of follow-up [16][17][18][19][20]. e study on Asian eyes by Ko et al showed very similar success rates to our results.…”

“…Our study showed higher success rates at all three intervals compared to that of Jiménez-Román et al, possibly due to the high proportion of S2 polypropylene models as the second AGV in their study; polypropylene models have been reported to have poorer survival estimates than the silicone models [19,21]. e success rates of the second AGV at the last follow-up in these studies ranged from 65.2% (Ko et al) to 84.2% (Smith et al), while our study had a lower success rate of 57.1% at the last follow-up [16][17][18]. is could be attributed to a longer mean follow-up time of 49.2 months in our study as compared to the studies evaluated (range: 21.4 months-37.8 months), which led to a greater proportion of AGV failure over time.…”

“…Ko et al [16] Smith et al [17] Nilforushan et al [18] Fatehi et al [19] Jiménez-Román et al [20] Our study Caprioli have demonstrated that while hypertensive phase occurs frequently after an AGV implantation, it resolves only in a minority of eyes [31]. ere is thus impetus for closer monitoring and quicker resolution of hypertensive phases, especially among the Asian population.…”

“…Levinson et al have also reported that the rate of tube exposure in sequential GDDs and primary GDDs were 13.1% and 5.8%, respectively, although this increased risk did not approach statistical significance [34]. When comparing with other Western studies evaluating second AGVs, Fatehi et al and Jiménez-Román et al reported tube exposure rates of 2.7% and 1.7%, respectively while Nilforushan et al and Smith et al did not report any incidence of tube exposure [17][18][19][20]. e higher rate of tube exposure in our study could be secondary to the tighter eyelids found in Asian eyes, which contribute to pressure necrosis of the conjunctiva over the implant.…”