Outcomes of the Shunt Tube Exposure Prevention Study: A Randomized Clinical Trial.

PURPOSE

To compare the long-term safety and efficacy of amniotic membrane-umbilical cord (AM-UC) and pericardium patch grafts in reducing glaucoma shunt tube exposure.

DESIGN

Multicenter, prospective, randomized clinical trial.

PARTICIPANTS

Adults with uncontrolled glaucoma undergoing glaucoma drainage device (GDD) implantation.

METHODS

Patients were randomized to receive GDD with either AM-UC or pericardium patch grafts to cover GDD tubes. Patients were followed up clinically with anterior segment (AS) OCT to assess patch graft stability and host-tissue integration prospectively.

MAIN OUTCOME MEASURES

Tube exposure, graft thinning, and graft-related complications.

RESULTS

A total of 81 eyes of 81 patients (50 women, 31 men) with a mean age of 67±13 years underwent GGD implantation using Baerveldt (n = 72) or Ahmed valve (n = 9). Tubes were inserted in the anterior chamber (n = 71), sulcus (n = 6), or pars plana (n = 4). Tube ligation was performed with Baerveldt GDD along with fenestration (n = 51) or orphan trabeculectomy (n = 21). Tubes were covered with AM-UC (n = 41) or pericardium (n = 40). The mean follow-up time was 29±8 months (range, 13-40 months). Tube exposure occurred in 1 eye (2%) in the AM-UC group at 3 months and in 2 eyes (5%) in the pericardium group at 2 and 6 months (P = 0.54). Sequential AS OCT showed better host-tissue integration and significantly less graft thinning in the AM-UC group. Early graft thinning (≤3 months) occurred in 5 eyes (12%) in the AM-UC group and in 17 eyes (43%) in the pericardium group (P = 0.002). Late thinning occurred in 2 eyes (5%) and 11 eyes (28%) in the AM-UC and pericardium groups, respectively (P = 0.007). Graft translucency and cosmetic appearance of the AM-UC graft were superior to those of the pericardium graft. No evidence of graft rejection or infection was associated with the patch grafts in either group.

CONCLUSIONS

Amniotic membrane-umbilical cord grafts are well tolerated and offer an alternative to pericardium for safe and stable tube shunt coverage. Its high-tensile strength, low immunogenicity, and excellent host-tissue integration significantly reduced graft thinning.