3-year TVT trial results: Tube shunts may be the better option

Three-year data from the Tube Versus Trabeculectomy (TVT) study shows that tube shunt surgery had a higher success rate compared to trabeculectomy with MMC. While IOP reduction and use of supplemental medical therapy were similar between the two procedures, the incidence of postop complications was higher following trabeculectomy.

TVT was a multicenter, prospective trial that randomized 212 patients with prior ocular surgery to either trabeculectomy with MMC or Baerveldt tube shunt. All patients had uncontrolled glaucoma and had previously undergone cataract extraction with IOL implantation and/or failed filtering surgery.

The goal of the study was to help surgeons make decisions for individual patients. Did they?

It could be argued that the results of the TVT study have altered what glaucoma surgeons choose to do in particular situations more than any other recent comparative trial involving glaucoma surgery.  Others might say that the TVT study only reflects directions that choices for glaucoma surgery are taking anyway based on many different factors, including other non-comparative studies, differences in the intensity of post-op management and practice population differences.

However, with the three-year results continuing to show similar IOP lowering results between the two procedures, along with increased success and fewer complications in the tube shunt group, many surgeons are probably much more likely to do more tube shunts.  Especially in patients with a history of failed trabeculectomy or in patients at relatively higher risk for failure of a primary trabeculectomy or in those more susceptible to early complications. TVT results have likely made surgeons more comfortable choosing tube shunts even as a primary glaucoma surgery in some cases. 

We may not yet have a complete comparison of the long-term complications between these two procedures. There are long-term complications associated with both procedures that the TVT study may not address even with five years of data. However, in the type of patient population enrolled in the TVT trial, tube shunts appear to be an equivalent if not better option compared to trabeculectomy.