PresserFlo in Latin America

Main Topics and Key Points:

• Positioning of the Presser Flow in the Surgical Therapeutic Arsenal:
  • Dr. Delgado has been using the Presser Flow in Colombia since approximately June 2023.
  • He considers it a "wonderful alternative" for glaucoma in slightly older stages than those traditionally addressed by MIGS (mild to moderate glaucoma).
  • It positions itself as a “bridge between the less and the more” on the surgical ladder, specifically between angular MIGS and traditional filtering surgeries (trabeculectomy, valves).
  • It is suitable for patients with moderate to severe glaucoma who present defects in the visual field, significant damage to the optic nerve, not controlled with maximum medical therapy, or with failed previous surgeries.
  • The main reason is that, being a surgery blister-forming, logra una pressure reduction superior to traditional MIGS, which is necessary for patients with lower pressure requirements.
• Treatment Algorithm and the Role of Presser Flow:
  • The current algorithm generally starts with medication or SLT (for primary open-angle glaucoma).
  • If this fails, the next step is often MIGS, especially for mild glaucoma where the pressure goal is moderate.
  • However, if the patient has uncontrolled moderate or advanced glaucoma, a traditional MIGS "maybe I don't know that it's not going to give me the appropriate result."
  • In these cases, you can "jump up the ladder" and choose major surgery such as Presser Flow, or even a trabeculectomy or valve surgery if the need is even greater.
  • The Presser Flow is ideally inserted after angular MIGS (stents or trabecular meshwork excision) but before major filtering surgeries, acting as that “space” or “bridge.”
• Surgical Technique and Considerations:
  • Use of Mitomycin C: Considered mandatoryThe "main enemy is undoubtedly fibrosis."
  • Early studies with 0.2% had a high failure rate; the change to 0.4 mg/ml significantly improved the success rate.
  • Although the Presser Flow material is a special polymer that produces less fibrosis ("immunologically inert"), the organism becomes fibrous and "at the end of the story, if we don't use mitomycin, our failure rate will be very high."
  • Mitomycin C should be applied posteriorly, as the device filters further behind the limbus (approximately 6 mm). It is recommended not to inject it into the limbus.
  • The concentration (0.4 mg/ml) and time (not less than 3 minutes) can be modulated according to the patient (previous surgeries, multi-treated/congestive conjunctiva).
  • Implant Location: It is put in the top, ideally between 10-11 a.m. and 1 a.m. Exactly 12 a.m. should be avoided to avoid affecting the superior rectus muscle. Preferred locations are superior nasal or superior temporal.
• Conjunctival Closure:
  •  Dr. Delgado describes herself as "a bit of a closure obsessive," ensuring that she brings the Tenon forward and leaving the center sealed (in addition to anchoring sutures at the margins) to prevent short- or long-term leaks.
• Prevention of Intraoperative Hyperfiltration:
  • If hyperfiltration ("leaks a lot") is observed during surgery (which can occur in patients with very high blood pressure, high myopia or advanced age), it is recommended cannulate the device with a tutor (Prolene 9-0 or Nylon 10-0) to reduce the lumen in a controlled manner and release it postoperatively if necessary.
• Combined Surgery:

• Combined with Phaco:
  • The general recommendation is do the procedures separately because the inflammation generated by phaco can reduce the success rate of Presser Flow by promoting fibrosis.
  • The inflamed aqueous humor would go to the filtration zone.
  • "It's preferable to try to do the procedures separately." It's ideal to do it on one patient. pseudophakic.
  • If combined, it is recommended to do it by two separate paths (phaco via temporal route, Presser Flow via superior route).
  • Phaco should be done first, wash the memory foam very well, and then apply the Presser Flow to avoid obstruction of the implant lumen (70 microns). It is not recommended to use viscoelastic in a Presser Flow alone.
  • If Presser Flow is performed first and a significant cataract remains, Dr. Delgado prefers to wait at least 6 months to properly control blood pressure before cataract surgery, although "the more time I can wait, the better." If the cataract has already been operated on, it doesn't matter to do the Presser Flow afterward.
• Combined with Retina Surgery:
  • Dr. Delgado has not performed any surgeries simultáneas Presser Flow with retina, but yes in patients with a history of retinal surgeries (vitrectomies, keratoplasties, buckles).
  • These cases often fall outside the "off-label" indications of the studies.
  • The challenge is the success rate and whether the patient will achieve optimal pressure control, especially if the pressure reduction requirement is high.
  • In patients with intraocular silicone, sometimes simply removing the silicone improves pressure. Sometimes it's better to do "less than more," see how they progress with retinal procedures, and then combine glaucoma surgery if necessary.
  • Dr. Delgado has not had to remove a Presser Flow due to retinal complications, but she has coordinated with retinal specialists to avoid the bleb area when injecting antiangiogenic agents. In extreme cases where an implant fails and visual potential is poor, cyclodestructive procedures could be considered.
• Management of Postoperative Complications:

• Postoperative Surveillance:
  • Initial monitoring is similar to that for traditional filtering surgery (first day, first week, then every two weeks for the first month). Topical corticosteroids are recommended. rigorous (even every 2–3 hours) in the first month to maintain anti-inflammatory effects. Dexmethasone or triamcinolone are options. Atropinization in phakic patients in the first week is useful if there are no contraindications.
• Postoperative Hyperfiltration:
  • It can occur through the lumen of the tube or through peritubular filtration (if the tunnel is too large).
  • If peritubular leakage is detected intraoperatively, it is best to remove the tunnel and make a new one.
  • Si la hiperfiltración es postoperatoria y hay desprendimientos coroideos/cámara plana, It is not ideal to refurbish with viscoelastic; saline solution is preferred.
  • If it is severe and does not resolve with medical management (atropinization, rest, head position), it is often necessary reopen the conjunctiva and cannulate the device (insert the implant) as would be done intraoperatively. Dr. Delgado had a case with choroidal detachments that she resolved by cannulating the implant postoperatively.
• Fibrosis (Late/Early Failure):

• It's a common cause of failure. It's not Tenon's obstruction (unlike Xen45), but rather "fibrosis above the implant" (a plastron).
• If the pressure rises due to fibrosis, when surgically inspecting and lifting the conjunctiva, the device "does filter, it filters perfectly."
• Handling involves put Mitomycin C back on on the back (modulating concentration/time) and release that fibrosis. They are "open reviews rather than needling."

Other Iatrogenesis:

• If a tunnel does not fit well intraoperatively ("false pathway"), it is best to create a new one without closing the old one. In cases where the tube tilts slightly upward (especially in thin conjunctiva), Dr. Delgado prefers lightly suture to sclera to deal with it and prevent extrusion.

Technology Adoption in Latin America:

• Even though technologies arrive "a little later" than in other countries, this provides the advantage of having more evidence and previous experience (from Europe, Canada, etc.) to better select patients and improve the chances of success.
• Glaucoma used to be a more limited field in terms of treatment options, leading many patients to worsen despite eye drops, reaching late stages with poor quality of life.
• The concept of interventional glaucoma It is key to be more interventionist (in a good way) to offer greater effectiveness, pressure control and improve the patient's quality of life.
• The Presser Flow offers a important differential in “larger” glaucomas where angular MIGS are not sufficient, sometimes avoiding trabeculectomy or inlet valves.
• The cost It is a significant barrier in economically challenged countries. However, it is comparable to the cost of other technologies (expensive drops, complex intraocular lenses).
• In Colombia, "many health insurance plans cover it" and it's "less expensive than other mixed technologies."
• It is essential that the doctor offer the patient the option, explaining the advantages, disadvantages and that no glaucoma surgery is definitive.
• The final decision should be the patient's, guided by the physician. Information should not be withheld because the patient is presumed unable to pay ("the decision is the patient's, not mine").
• The arrival of these technologies in Latin America is a "fantasy" that "makes us better too because we grow in our technique" and "we also grow in options for people, which is ultimately the best." It's not a "premium option for the elite"; many patients can benefit by making an effort.

Relevant Quotes:

• "It came in as a wonderful alternative for glaucoma in slightly older states compared to all the microinvasive therapies."
• "The reason is that since it is a blister-forming surgery, it will have a better impact on the level of pressure reduction for patients who specifically need pressures. Well, at lower levels, avoiding a bit what traditional surgery is."
• "That's like the profile of the glaucoma patient, between slightly more moderate to severe, who requires a pressure reduction, which is relevant because it is a pressure reduction greater than what traditional mixes provide."
• "It's like a very explicit bridge. Okay, it's a bridge between the less and the more exactly."
• "I would tell you that it is mandatory to do it with mitomycin because our main enemy is undoubtedly fibrosis, as in any procedure, even a more invasive one."
• "But at the end of the story, if we don't use mitomycin, our failure rate will be very high."
• "The recommendation is to try to do things separately because ultimately, even if it's a very, very well-done phaco, obviously, and a less difficult phaco, some more inflammation will still be generated, and that aqueous humor, as we were saying just now, will go precisely to the filtration area and will decrease our success rate."
• «So yes, what we first have to keep in mind is that one says, well, the device has a very, very finite light, the probability of causing hypotonia is pathophysiologically lower. But it can happen.»
• "In patients whose leaks are significant intraoperatively, I prefer to cannulate the device with a guide."
• "Renovating with viscoelastic is better, but not ideal. If you have to go into renovation, you should renovate with saline solution."
• "What a lot of people say is that it's too expensive, right? I mean, how am I going to offer it to my patient? And sometimes they don't even mention it."
• "I think that when things arrive a little later, we have a great advantage. And it's because they've already done it in other places, there's more evidence of both the good and the bad. So that gives us the opportunity to choose the patient better."
• "For me, the arrival of this... not only brings one more option but also changes the mentality a little to be able to offer something better. I think better for many patients."
• "Price is always going to come up... obviously there's going to be a cost."
• «It seems like a fantasy to me that all these things that make us better come to us, too, because we grow in our technique… and we also grow in options for people, which is ultimately the best thing.»

Implications/Applicability:

• Dr. Delgado's experience suggests that the Presser Flow is a valuable and viable tool for glaucoma management in Latin America, not just in markets with greater purchasing power.
• Its positioning as a bridge between MIGS and major surgeries is a useful framework for surgical decision-making.
• Emphasis on Mitomycin C and strategies to manage hyperfiltration and fibrosis are crucial for postoperative success.
• Considerations regarding combined surgery (separate if possible, careful management if not) are relevant practices.
• The discussion about cost underscores the need to inform the patient about all available options, allowing them to make the final decision.

Next Steps/Additional Questions (if this were a conversation):

• To explore longer-term follow-up of patients with Presser Flow in Colombia.
• Detail the specific protocols for the use of Mitomycin C (concentration, time, area of application) according to the patient's profile.
• Discuss the bureaucratic process for health insurance approval and coverage in other countries in the region.
• Comparison of outcomes and learning curves with Presser Flow versus trabeculectomy in Latin American centers.