Outcomes and Complications of Ahmed Tube Implantation in Asian Eyes

Systematic Literature Reviews Comparing the Long-Term Safety Outcomes for the Port Delivery System with Ranibizumab (PDS) Versus Other Ocular Implants

OBJECTIVES

To determine whether the types and rates of post-surgical complications associated with the Port Delivery System with ranibizumab (PDS) are comparable with those reported for other ocular implants that cross the sclera.

METHODS

Systematic literature reviews were conducted to determine the long-term (≥ 18-month) safety of ocular implants that cross the sclera in clinical trials and real-world studies. Complication types and rates were compared with those reported for the PDS in phase III clinical trials (Archway, Pagoda, and Pavilion).

RESULTS

Sixteen clinical trials (24 publications) and 43 real-world studies were identified reporting 30 complications in eyes with 15 implant types and 8 ocular diseases. Implants were associated with an acceptable, well-characterized safety profile, with most complications resolving spontaneously or with treatment. Device-related complications were reported in 0.7% (0.0-5.0%) of study eyes in clinical trials and 1.3% (0.0-14.5%) of eyes in real-world studies. Rates of conjunctival complications were 2.1% (0.0-22.8%) and 2.2% (0.9-4.6%), respectively. The overall types and rates of adverse events of special interest reported for the PDS in phase III trials (cataract, conjunctival bleb, vitreous hemorrhage, conjunctival erosion, conjunctival retraction, endophthalmitis, implant dislocation, retinal detachment, and hyphema) were within the ranges reported for other ocular implants.

CONCLUSIONS

The rates of complications reported in phase III clinical trials for the PDS were within the ranges reported for other ocular implants that cross the sclera. This suggests that the long-term safety of the PDS is consistent with other ocular devices established in ophthalmology clinical practice.

TRIAL REGISTRATION

PROSPERO international prospective register of systematic reviews: CRD5202234129, CRD42022343129.

Microenvironment-regulated dual-hydrophilic coatings for glaucoma valve surface engineering

Glaucoma valves (GVs) play an essential role in treating glaucoma. However, fibrosis after implantation has limited their long-term success in clinical applications. In this study, we aimed to develop a comprehensive surface-engineering strategy to improve the biocompatibility of GVs by constructing a microenvironment-regulated and dual-hydrophilic antifouling coating on a GV material (silicone rubber, SR). The coating was based on a superhydrophilic polydopamine (SPD) coating with good short-range superhydrophilicity and antifouling abilities. In addition, SPD coatings contain many phenolic hydroxyl groups that can effectively resist oxidative stress and the inflammatory microenvironment. Furthermore, based on its in situ photocatalytic free-radical polymerization properties, the SPD coating polymerized poly 2-methylacryloxyethylphosphocholine, providing an additional long-range hydrophilic and antifouling effect. The in vitro test results showed that the microenvironment-regulated and dual-hydrophilic coatings had anti-protein contamination, anti-oxidation, anti-inflammation, and anti-fiber proliferation capabilities. The in vivo test results indicated that this coating substantially reduced the fiber encapsulation formation of the SR material by inhibiting inflammation and fibrosis. This design strategy for dual hydrophilic coatings with microenvironmental regulation can provide a valuable reference for the surface engineering design of novel medical implantable devices. STATEMENT OF SIGNIFICANCE: Superhydrophilic polydopamine (SPD) coatings were prepared on silicone rubber (SR) by a two-electron oxidation method. Introduction of pMPC to SPD surface using photocatalytic radical polymerization to obtain a dual-hydrophilic coating. The dual-hydrophilic coating effectively modulates the oxidative and inflammatory microenvironment. This coating significantly reduced protein contamination and adhesion of inflammatory cells and fibroblasts in vitro. The coating-modified SR inhibits inflammatory and fibrosis responses in vivo, promising to serve the glaucoma valves.

Clinical outcomes of Ahmed glaucoma valve implantation in primary open-angle glaucoma and pseudoexfoliative glaucoma

PURPOSE

To investigate the clinical outcomes of Ahmed glaucoma valve (AGV) implantation in primary open-angle glaucoma (POAG) and pseudoexfoliative glaucoma (PEXG).

METHODS

The patients who underwent AGV implantation for POAG and PEXG between January 2015 and December 2021 in a single tertiary center eye clinic were reviewed retrospectively. Thirty-one eyes with the diagnosis of POAG constituted Group 1 and 40 eyes with the diagnosis of PEXG constituted Group 2. The primary outcome measures were intraocular pressure (IOP) changes after AGV implantation and surgical success at the last visit. We evaluated complete and qualified surgical success using the following three criteria: (1) IOP ≤ 21mmH g, (2) IOP ≤ 18 mmHg, and (3) IOP ≤ 15 mmHg, as well as the absence of any serious complications, such as light perception loss and phthisis bulbi, and additional de novo glaucoma surgery.

RESULTS

The mean follow-up times were 25.2 (± 21.4) months and 27.6 (± 19.8) months for Groups 1 and 2, respectively (p > 0.05). In Groups 1 and 2, the mean preoperative IOPs were 31.9 ± 9.4 mmHg and 32.3 ± 8.4 mmHg, respectively, which significantly reduced to 14.5 ± 0.7 mmHg and 11.6 ± 0.6 mmHg, respectively at the last postoperative visit (p < 0.001 for both). The mean IOP value at the last visit was statistically significantly lower in Group 2 (p = 0.006). At the last visit, the number of eyes with qualified success according to criteria 1, 2, and 3 was 26 (83.9%), 25 (80.6%), and 18 (58.1%), respectively, in Group 1 and 39 (97.5%), 39 (97.5%), and 32 (80%), respectively, in Group 2. The comparison of the qualified success rates showed statistically significantly higher rates in Group 2 for criterion 2 (p = 0.038).

CONCLUSION

AGV implantation had high success rates in both POAG and PEXG, but at the final visit, lower IOP levels were reached in the latter.

Five-Year Outcomes of Graft-Free Tube Shunts and Risk Factors for Tube Exposures in Glaucoma

PRCIS

Use of a scleral tunnel technique instead of a patch graft can be considered in most cases of tube shunt implantation. Grafts may still be considered in younger (<65 y old) East Asians.

PURPOSE

(1) To assess the risk factors for tube exposure with a graft-free implantation technique and (2) to examine 5-year outcomes of graft-free tube shunt insertion.

METHODS

This was a retrospective case series of 204 consecutive eyes undergoing a glaucoma tube shunt implantation with a scleral tunnel technique in lieu of a graft. Preoperative and postoperative best-corrected visual acuity, intraocular pressure, and number of glaucoma medications were compared. Failure was defined as the following: (1) intraocular pressure >21 mm Hg or ≤5 mm Hg on 2 consecutive visits after 3 mo; (2) required additional glaucoma surgery; (3) loss of light perception. Univariable and multivariable regression analyses were conducted to identify risk factors of tube exposures.

RESULTS

Intraocular pressure and the number of glaucoma medications were significantly decreased at all postoperative time points ( P <0.001). Success rates were 91% at year 1, 75% at year 3, and 67% at year 5. The most common early (<3 mo) complication was tube malpositioning. The most common late (>3 mo to 5 y) complications were corneal complications and uncontrolled intraocular pressure. By year 5, 6.9% of tubes were exposed. Multivariable regression showed that age less than 65 years old (odds ratio: 3.66, P =0.04) and East Asian ethnicity (odds ratio: 3.36, P =0.04) were associated with significantly increased risk of tube exposure.

CONCLUSIONS

Graft-free glaucoma tube implantation has comparable long-term outcomes and complication rates to shunts with a graft. Younger (<65 y old) East Asians are at greater risk of tube exposure without a graft.

Comparison of Short and Long-Tunnel Needle Track for Ahmed Glaucoma Valve Implantation in a Private Eye Center in the Philippines: A Retrospective Study

Purpose

This study aimed to compare the success and complication rates among patients implanted with Ahmed Glaucoma Valve (AGV) using the short and long tunnel technique through retrospective chart review.

Patients and Methods

We reviewed 54 charts of adult patients who underwent AGV implantation using a Short-Needle Track (SNT) or Long-Needle Track (LNT) technique. Intraocular pressures (IOP), Best Corrected Visual Acuity (BCVA) and number of medications were recorded pre-operatively, and at Day 1, 3, 7, Month 1, 3, 6 post-operatively. Treatment success, occurrence of Hypertensive Phase (HP), complication and procedures done after AGV implantation were compared between the two groups using one-tailed Z-test of proportions.

Results

A total of 20 (LNT) and 21 (SNT) charts were included in the study. There was no significant difference between the median postoperative IOP, BCVA, and number of anti-glaucoma medications between the two groups at each time interval. The comparison between the occurrence of HP (P = 0.435) and success rates (P = 0.476) between the two groups yielded no significant difference. Flat/shallow anterior chamber (AC) was seen exclusively in three eyes (14%) in the SNT group (P = 0.039). There was one occurrence of plate exposure in the LNT group (P = 0.149).

Conclusion

The LNT technique of AGV Implantation may be used as an alternative to the traditional SNT (with autologous graft). The long needle track offers the advantage reducing the risk of complications arising from shallow anterior chamber post-operatively.

Risk Factors for Hyphema Following Kahook Dual Blade Goniotomy Combined With Phacoemulsification

PRCIS

Hyphema development after Kahook Dual Blade (KDB) excisional goniotomy was significantly associated with postoperative day 1 intraocular pressure (IOP) ≤12 mm Hg, male sex, and narrow iridocorneal angles, but not with continuation of anticoagulation or antiplatelet therapy.

PURPOSE

To identify risk factors of hyphema development after KDB goniotomy combined with phacoemulsification.

METHODS

In all, 202 eyes in 145 patients who received a KDB goniotomy combined with phacoemulsification between February 21, 2017 and February 18, 2020 were evaluated for preoperative factors that were predictive of postoperative hyphema. Hyphema was defined as the development of ≥1 mm layered blood in the anterior chamber. The primary outcome was the association between various preoperative factors and the development of postoperative hyphema. Binomial logistic regression was used to analyze risk factors of hyphema development while controlling for other variables.

RESULTS

Hyphema occurred in 8.4% (17/202) of patients on day 1 after KDB goniotomy combined with phacoemulsification. Male sex ( P =0.008), angle closure glaucoma ( P =0.036), and postoperative day 1 IOP ≤12 mm Hg ( P =0.049) were significantly correlated with hyphema development while controlling for other variables. Preoperative anticoagulation and antiplatelet therapy had no association with hyphema development ( P =0.538).

CONCLUSIONS

Postoperative hyphema was associated with male sex, narrow iridocorneal angles, and a postoperative day 1 IOP lower than typical episcleral venous pressure when controlling for other variables. Preoperative anticoagulation or antiplatelet therapy was not associated with developing postoperative hyphema in this study; however, further investigation is needed before recommendations can be made.

Effect of immediate shallow anterior chamber after Ahmed glaucoma valve implantation on intermediate-term intraocular pressure control

Purpose:

To evaluate the incidence of shallow anterior chamber in the early postoperative period following Ahmed glaucoma valve (AGV) implantation and its effect on the hypertensive phase (HP), intermediate-term intraocular pressure (IOP) control, and success rate.

Methods:

A retrospective analysis of 369 eyes of 360 patients who underwent AGV implantation between January 2005 and January 2020 with a minimum follow-up of 2 months was performed. Twenty-six patients developed shallow anterior chamber (AC) within 8 weeks following surgery (cases). They were compared with 39 randomly selected controls (no shallow AC post AGV). HP (IOP spike >21 mmHg), use of ocular hypotensive medications, and other associations were compared.

Results:

Incidence of shallow AC post AGV was 7% (95% confidence interval [CI] 4, 9). The onset of shallow AC was 3 ± 2.1 days and resolved within 6 ± 4.7 days. Hypotony (12 [47%] vs. 1 [2.5%], P 0.0001) and choroidal detachment (CD; 7 [27%] vs. 3 [8%], P 0.03) were more common in cases compared to controls. The HP occurred in 11 (43%) cases versus 13 (34%) controls (P 0.4). Cases required more ocular hypotensive medications than controls at the end of 8 weeks (1.1 ± 1 vs. 0.5 ± 0.5, P 0.01). There was no significant difference in the qualified success between the groups at 1 year.

Conclusion:

The development of postoperative shallow AC post AGV implantation was not detrimental to IOP control at 1 year. However, there is a need to monitor the occurrence of HP in these eyes.

Pars Plana Ahmed Valve Implantation for Vitrectomized Eyes With Refractory Glaucoma

This study aimed to analyze the surgical outcomes of pars plana Ahmed valve implantation in vitrectomized eyes with refractory glaucoma. We performed a retrospective case review of consecutive patients with refractory glaucoma after undergoing pars plana vitrectomy who underwent pars plana Ahmed valve implantation between July 2019 and December 2020 at the glaucoma unit of the Affiliated Changshu Hospital of Xuzhou Medical University (Changshu, China). All the patients were followed up for ≥12 months postoperatively. We recorded pre- to postoperative changes in best-corrected visual acuity (BCVA), intraocular pressure (IOP), number of anti-glaucoma medication, corneal endothelial count, and surgical complications, if any. There was a significant improvement in the median BCVA from 2.30 (0.87, 2.30) logMAR preoperatively to 1.70 (0.70, 2.30) logMAR at discharge and 1.0 (0.52, 1.85) at final examination (p = 0.011, p = 0.001). Compared with the preoperative IOP level, there was a significant decrease in the postoperative IOP at each postoperative time point (p < 0.001). There was a significant reduction in the median number of anti-glaucoma drugs (including postoperative ocular massage), from 3.00 (2.00, 3.00) preoperatively to 0.00 (0.00, 1.00) at the last follow-up postoperative examination (p < 0.001). A 29-year-old woman with proliferative diabetic retinopathy who underwent surgical treatment at 5 months postoperatively for fibrous wrapping formed around the plate of the Ahmed valve showed an IOP of 14 mmHg at the last follow-up. Our findings indicated that pars plana Ahmed valve implantation can be safely performed for managing vitrectomized eyes with refractory glaucoma.

Operative Complications of Glaucoma Drainage Implant Tube Insertion Through the Sulcus for Pseudophakic Eye

PRECIS

Malposition of the tube through the ciliary sulcus is more frequently observed with the Ahmed glaucoma valve (AGV) than the Baerveldt drainage implant (BDI) due to the weaker rigidity of the Ahmed tube.

PURPOSE

To report intraoperative and early postoperative complications of ciliary sulcus tube insertion of glaucoma drainage implants (GDIs).

PATIENTS AND METHODS

We performed retrospective analysis of 104 eyes of 94 patients with GDI tube insertion through the ciliary sulcus were performed. The rigidities of tubes were also examined using a microcompression tester.

RESULTS

The mean observation period was 20.0 (range, 6 to 60) months. Thirteen eyes were treated with the BDI and 91 were with the AGV. The mean age of the patients was 69.3 (34 to 90) years. The mean intraocular pressure was 27.9 mm Hg before surgery and 12.9 mm Hg after surgery (P<0.01). Upon tube insertion 42/91 eyes (46%) with the AGV required reinsertion of the tube due to malpositioning, whereas only 1/13 (8%) eyes with BDI did (P<0.01). Transient hyphema (12 eyes) and hypotony (12 eyes) were observed as early postoperative complications with the AGV. Seven eyes with hypotony were treated by proline stenting of the tube. We could not accomplish sulcus insertions in 4 eyes. Microcompression analysis of the tubes showed that the BGI tube was more rigid than that of the AGV.

CONCLUSIONS

Ciliary sulcus insertion of the tube is an effective method to control intraocular pressure. The tube of the AGV was more difficult to insert through the sulcus than the BDI due to its weaker rigidity.

Surgical outcomes of Ahmed glaucoma valve implantation in patients with glaucoma secondary to iridocorneal endothelial syndrome

OBJECTIVES

To evaluate the long-term outcome of patients with iridocorneal endothelial (ICE) syndrome who underwent Ahmed glaucoma valve implantation surgery for uncontrolled glaucoma.

METHODS

Eighteen patients who suffered from unilateral ICE syndrome with uncontrolled glaucoma and subsequently underwent Ahmed aqueous shunt surgery at Zhongshan Ophthalmic Center between January 2008 and December 2016 were reviewed. Outcome measures included intraocular pressure (IOP), the use of glaucoma medications, visual acuity, further surgical interventions, and surgical complications.

RESULTS

The mean IOP was reduced from 34.8 ± 10.6 mmHg on 3.6 ± 0.5 medications to 17.4 ± 4.9 mmHg (t = 6.791, P = 0.000) on 1.6 ± 1.1 medications (Z = -3.545, P = 0.000) at the last follow-up (42.0 ± 19.3 months). Five eyes (27.8%) achieved complete success, nine (50.0%) achieved qualified success, and the remaining four (22.2%) were considered failures. Survival was 94.4% at 1 year, 88.1% at 2 years, and 73.5% at 3 years. Four cases displayed a flat anterior chamber and were treated with a single anterior chamber reformation surgery with no recurrence. No other complications related to the glaucoma drainage implants occurred in this series.

CONCLUSIONS

Ahmed glaucoma valve implantation appears to be a safe and effective method for treating glaucoma secondary to ICE syndrome. Postoperative shallow anterior chamber and hypotony may occur but responds well to the treatment. Early consideration may be given to aqueous shunt surgery in patients with glaucoma secondary to ICE syndrome when trabeculectomy fails.

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

Results

The cumulative failure rates were 9.5%, 20.0%, 32.5%, and 46.0% at six months, one year, two years, and three years of follow-up. At final follow-up, complete success and qualified success rates were 23.8% and 33.3%, respectively; mean IOP and number of medications decreased by 5.6 mmHg (23.9%) and 1.7 mmHg (54.8%), respectively, from preoperative baseline (P < 0.01). More common postoperative complications included hypertensive phase (38.1%), corneal decompensation (23.8%), and tube exposure (14.3%).

Conclusion

An additional AGV implant had good short and modest long-term effectiveness in reducing IOP following a failed glaucoma tube shunt in Asian eyes, with the mentioned common postoperative complications to be actively monitored and managed.