Pathological Findings in Eyes with the Ganciclovir Implant

Transcription

1 Pathological Findings in Eyes with the Ganciclovir Implant Sunil K. Srivastava, MD, 1 Daniel F. Martin, MD, 1,2 Susan D. Mellow, RN, 1 David J. Parks, MD, 1 Kourosh Dastgheib, MD, 1 Chi-Chao Chan, MD 1 Objective: To examine the pathologic findings of eyes treated with ganciclovir implants. Design: Retrospective consecutive case series. Participants: Thirty-three eyes from 19 AIDS patients with ganciclovir implants. Methods: Pathologic specimens collected from 1993 through 1999 at the National Eye Institute were reviewed. Thirty-three eyes from 19 patients were identified with ganciclovir implants. The submitted eyes then were sectioned through the implant site and stained with hematoxylin and eosin, periodic acid Schiff, and other special stains when needed. Medical records, including operative and postoperative notes, were reviewed carefully. Main Outcome Measure: Light microscopic findings at and around the site of implantation. Results: Scars of surgical perforation were present in all eyes. Fibrous ingrowth developed from the implant site into the vitreous in 32 of the 33 eyes. Vitreous hemorrhage was present in 18 of the 33 eyes. Poor wound apposition was found in 2 of the 33 eyes, both of which had undergone multiple procedures. Foreign body giant cell reactions were observed in most of the eyes related to suture material. Thirty-two of the 37 implant sites were located within the pars plana, whereas the other 5 were either on the border of the pars plana and pars plicata (n 4) or within the pars plicata (n 1). Hyalinization, atrophic changes of the ciliary body in the area of implantation, or both were observed in 18 eyes. Conclusions: The ganciclovir implant is well tolerated within the eye. Fibrous ingrowth is present in most eyes and seems to be a benign occurrence because of its limited extension. Microscopic vitreous hemorrhage is present in many eyes, especially those that underwent multiple procedures. Poor wound apposition occurred rarely and was found only in eyes that had undergone multiple procedures. Ophthalmology 2005;112: by the American Academy of Ophthalmology. Since its introduction, the ganciclovir implant has become one of the major therapeutic options in the treatment of cytomegalovirus retinitis. Randomized clinical trials comparing its use with intravenous ganciclovir revealed a greater median time to progression of retinitis with a decline in the incidence of complications associated with systemic therapy in those who received the implant. 1 3 Although the incidence of cytomegalovirus retinitis has declined with the introduction of highly active antiretroviral therapy, 3,4 the ganciclovir implant demonstrates not only effectiveness against cytomegalovirus in the eye, but also the potential benefits of intraocular drug delivery: greater intravitreal drug concentration than that available with systemic therapy, resulting in reduction and potential elimination of systemic adverse effects. 5 Originally received: July 13, Accepted: November 7, Manuscript no Laboratory of Immunology, National Eye Institute, National Institutes of Health, Bethesda, Maryland. 2 Department of Ophthalmology, Emory Eye Center, Atlanta, Georgia. Presented at: Association for Research in Vision and Ophthalmology meeting, April, 2004; Fort Lauderdale, Florida. Correspondence to Chi-Chao Chan, MD, Building 10, Room 10N103, 10 Center Drive, NIH/NEI, Bethesda, MD chanc@ nei.nih.gov. These advantages have spurred the development of other intraocular implants, such as the fluocinolone implant for the treatment of uveitis, diabetes, and age-related macular degeneration and the cyclosporin implant for the treatment of uveitis. 6,7 Current and future investigations examining the use of intravitreal therapies for long-term diseases such as age-related macular degeneration and diabetic retinopathy certainly will lead to an increasing number of intraocular implants developed and applied. With the potential increasing number of intraocular implant devices under development for long-term use, it is important to evaluate the effects of the implant on the surrounding ocular tissue. Currently, the only other reports of the pathologic features of eyes treated with the ganciclovir implant have a limited number of specimens and tend to focus on the pathologic features of the areas of retinitis We examined and reviewed our relatively large number of specimens with ganciclovir implants with specific focus on the area of implant placement. Materials and Methods The Institutional Review Board of the National Eye Institute approved this study for human subjects. Pathologic specimens obtained from 1993 through 1999 at the National Eye Institute by the American Academy of Ophthalmology ISSN /05/$ see front matter Published by Elsevier Inc. doi: /j.ophtha

2 Srivastava et al Pathology of the Ganciclovir Implants were reviewed. Thirty-three eyes from 19 patients were identified with ganciclovir implants. These eyes were obtained within 48 hours of death and were fixed in 10% formalin for at least 48 hours before processing. In most eyes, the implants were removed carefully before microscopic evaluation. After appropriate fixation, the submitted eyes were embedded in paraffin, then serial sections were cut through the implant site and were stained with hematoxylin and eosin, periodic acid Schiff, and other special stains when needed. In situ detection of apoptotic cells was conducted on paraffin sections using TACS Blue Label Detection kit (Trevigen, Inc., Gaithersburg, MD) according to the manufacturer s protocol as described previously. 11 Available medical records of each patient were reviewed. Particular attention was paid to clinical complications of the implants. Operative notes also were considered where available to review surgical complications. Data on patients demographics and clinical history also were reviewed. Results A total of 33 eyes from 19 patients with AIDS and either cytomegalovirus (CMV) retinitis (31 eyes) or progressive outer retinal necrosis (2 eyes) were obtained, including 14 sets of paired eyes and 5 unpaired eyes. The mean age of the patient at time of death was 38 years (range, years). Eighteen patients were male and 1 was female. The mean duration from diagnosis of CMV retinitis to death was 352 days. Eighteen eyes had more than 1 implant placed, and 3 of these eyes had more than 2 implants placed. Four eyes had multiple implant sites, including 1 eye that had implants exchanged at 2 separate sites. The mean duration from initial implant placement to death was 273 days. The mean duration from last implant placement to death was 148 days. In all eyes with a clinical diagnosis of CMV, isolated CMV cells with or without active CMV retinitis were found (Fig 1A). Seven eyes had patches of active CMV lesions present (Fig 1B). In 1 eye with inactive CMV, a subretinal abscess with gram-positive cocci was found; this patient died of septicemia caused by gram-positive cocci. 12 In 1 additional eye with inactive CMV, a toxoplasmosis cyst was seen. In the 2 eyes with a diagnosis of progressive outer retinal necrosis, dense chorioretinal scarring and extensive retinal atrophy were present. A terminal deoxynucleotidyl transferase mediated deoxyuridine triphosphate nick-end labeling (TUNEL) assay showed various degrees of apoptosis at the CMV lesions as reported previously. 11 In all eyes, scars of healed surgical wounds were present at the implant site (Fig 2). Normal pars plana tissue surrounding the implant site was replaced by collagen fibrous tissue in all specimens. This fibrous tissue was present either with or without entrapment of pigmented ciliary epithelial cells. In 32 of the 33 eyes, areas of fibrous tissue ingrowth originating from the pars plana wound into the vitreous anterior, posterior to the implant strut imprint, or both were present. These areas typically extended up to 1 mm into the vitreous. In some, this fibrous tissue extended onto the peripheral retina or anterior hyaloid base, and in 1 eye, it was adherent to peripheral retina, pulling gliotic retina onto the pars plana (Fig 3). In some of the specimens, a small number of mononuclear inflammatory cells was present in or around the fibrous ingrowth. No fibrous ingrowth was observed through the strut. Thirty-one of the 33 eyes had well-opposed surgical scars. One of the 2 eyes with poor wound closure (Fig 4) had simultaneous ganciclovir implant exchange and pars plana vitrectomy, whereas the other had ganciclovir implant exchange followed by a pars plana vitrectomy 1 month later. Of the 14 other eyes examined that had an implant exchanged (including 2 eyes that had 2 exchanges and 2 eyes that had 2 exchanges at 2 separate implant sites), all had good wound apposition without any sign of dehiscence. Only 2 of these 14 eyes, however, had a simultaneous vitrectomy performed during the exchange. Figure 1. Photomicrograph revealing (A) isolated cytomegalovirus (CMV) cells (arrows) containing both intranuclear inclusions and cytoplasmic inclusions in a treated eye and (B) necrotic retina with multiple CMV cells (arrows) consistent with active CMV retinitis in another eye (stain, hematoxylin eosin; original magnification, 200). 781

3 Ophthalmology Volume 112, Number 5, May 2005 Figure 2. A well-placed implant shown in (A) a gross photograph and (B) a photomicrograph. There is a well-healed surgical scar with fibrous ingrowth extending into the vitreous (stain, hematoxylin eosin; original magnification, 100). Eighteen eyes were found to have microscopic evidence of a vitreous hemorrhage. The extent of hemorrhage ranged from a few fresh erythrocytes clumped near the sclerotomy site (Fig 5) to a moderately sized blood clot and ghost red blood cell debris. Eleven of the 18 eyes with vitreous hemorrhage underwent at least 1 additional intravitreal surgery; 9 eyes underwent at least 1 implant exchange, 3 eyes underwent an additional implant placed at another site, and 3 eyes also underwent a pars plana vitrectomy. The position of the implant in the eyes with regard to the sclera also was examined. Eight eyes were found to have the implant strut imprint limited to the inner one third of the sclera, whereas 7 of the eyes had the strut imprint spanning the inner two thirds of the sclera, and 2 eyes had the strut imprint implanted through at least two thirds of the sclera. The location of the strut imprint in the other 16 eyes was not identified clearly. The location of the incision site also was investigated. Of the 37 total implanted pellets examined (29 eyes with 1 implant and 4 eyes with 2 implants), 32 were placed entirely within the pars plana, whereas 4 were on the border between the pars plana and pars plicata, and 1 implant was placed in the pars plicata. No implants were placed within the ora serrata or peripheral retinal space. No evidence of complete dissolution of sutures (8-0 nylon) was observed in these cases within a relatively short follow-up. Foreign body giant cell reactions were noted in 28 of the 33 eyes surrounding fragments of suture material around the implant site (Fig 6). In some cases, giant cells were noted with other inflammatory cells, including lymphocytes surrounding the suture tract. In 19 eyes, abnormalities of the ciliary body were noted. Mild hyalinization, atrophy, or both were seen most commonly in these eyes. A TUNEL assay revealed that a mild to moderate number of cells in the ciliary body underwent apoptosis (Fig 7). In 5 of the 6 eyes in which the implant site was placed either on the border of the pars plicata and the pars plana or in the plane of the pars plicata, moderate hyalinization of the ciliary body was found. In one of these eyes, fibrosis of the ciliary muscle near the implant site was seen, and in another eye the ciliary epithelium was folded. Lens findings also were reviewed. Thirteen of the 33 eyes had mild to moderate lens changes, including posterior cortical fragmentation and globulin formation; 2 eyes were pseudophakic. Of the 13 eyes with lens changes, 11 underwent multiple surgical procedures. Operative reports were reviewed and were available for 22 of the 33 eyes. No major complications were noted in these eyes. Small vitreous hemorrhages were found in 5 eyes in the immediate postoperative period. One of these eyes was noted to have developed low intraocular pressure (hypotony) that was resolved 1 week later. A peripheral choroidal fold also was observed in 1 additional eye. Twenty-eight of the 33 eyes reviewed were enrolled in a clinical trial examining the use of the ganciclovir implant. As such, multiple physicians performed the insertion of the implants, although 1 surgeon (DFM) performed most of the procedures. The surgical technique in these patients was the same as described in previous reports. 1 In the other 5 eyes, operative reports were not available. Postoperative notes also were detailed and reviewed for 20 of the 33 eyes. Seven eyes had small vitreous hemorrhages or pigmented vitreous cells noted on the examination notes. No major complications, including lens damage, were noted, nor were there any comments on poor wound closure or frank dehiscence. None of the 19 patients included in this study received highly active antiretroviral therapy. Discussion Although topical and systemic medications can be used to treat ocular diseases, intraocular drug levels are limited. The Figure 3. Photomicrograph of a peripheral retinal detachment occurring secondary to traction from fibrous tissue extending from the implant site (not shown; stain, hematoxylin eosin; original magnification, 200). 782

4 Srivastava et al Pathology of the Ganciclovir Implants Figure 4. Poor wound closure in an eye that had a ganciclovir implant exchange and subsequent pars plana vitrectomy for retinal detachment. Note the dehiscence involved all layers (stain, hematoxylin eosin; original magnification, 100). blood retinal barrier created by retinal pigment epithelia and retinal capillary endothelia prevents intravitreal delivery of systemically administered medication into the retina. Systemic therapy is limited further by the plasma binding of the drug, which can be overcome by increasing the dose delivered to the patient with rising toxicity. 5 Intravitreal injection of medication offers greater intraocular concentration than that available with topical or systemic therapy by avoiding those barriers. However, the dose effect is short lived, requiring multiple and sometimes frequent injections. Although intravitreal injections have a relatively low risk of complications, the inconvenience and anxiety associated with them limits the usefulness for longterm therapy. Current intraocular implants begin with a pellet of drug, which is compressed and then coated, typically with polyvinyl alcohol. 5 Sustained intravitreal concentrations of drug are obtained for several months to several years, and systemic exposure is eliminated. Complications can occur with the surgical implantation of these devices, but are not very common. 1 3,5 7 The ganciclovir implant lasts for approximately 6 to 9 months; those who require therapy for longer periods typically have their implant exchanged or have an additional device implanted. When first developed, the average lifespan for a patient with CMV retinitis was limited, but with improvement in therapy, there are a significant number of patients receiving multiple implants. 13 Options for these patients include implant exchange through the initial wound or insertion of an additional implant through a new surgical site The potential for future implant devices to deliver medication for a few years along with the need for these devices Figure 5. Photomicrograph displaying clumps of red blood cells adherent to the sclerotomy site (stain, hematoxylin eosin; original magnification, 100). 783

5 Ophthalmology Volume 112, Number 5, May 2005 Figure 6. Photomicrograph showing multiple fragments of suture material, some with surrounding giant cells (arrows; stain, hematoxylin eosin; original magnification, 100). to be used for patients with life-long chronic disease warrants an examination of the effects of the implant to the surrounding ocular tissue. All of our patients were treated in the era of human immunodeficiency virus disease before highly active antiretroviral therapy and on average had their implant for approximately 9 months. In general, the implants effectively controlled CMV retinitis. In addition, they were tolerated well without much damage to surrounding tissue. Typically, a collagen scar forms around the implant with a thin layer of fibrous growth into the vitreous. The fibrous growth may contain a few inflammatory cells. Although this fibrous ingrowth seems benign, there is potential for this ingrowth to be adherent and to pull on the peripheral retina. There was a relative lack of inflammation noted in these specimens, possibly because of the diminished inflammatory response in human immunodeficiency virus-infected patients. 18,19 In immunocompetent patients, there could be an increased inflammatory reaction around the implant site. The vast majority of the implants had good closure and alignment of the surgical wound, reducing the potential for infection in these immunosuppressive patients with AIDS. In the 2 patients in whom poor closure was noted on pathologic examination, no clinical signs of wound dehiscence were described. These cases of poor closure only occurred in the eyes with implant exchanges performed with either simultaneous or subsequent pars plana vitrectomy. In the 14 other eyes that underwent implant exchanges, and in the 4 eyes examined with multiple implants, there were no signs of poor closure or dehiscence. From our findings, it seems that the risk of poor wound apposition is greater in those eyes subjected to implant exchanges with additional vitreous surgery (either concurrent or consequent). In this series, eyes in which a new site for implantation was chosen did not have any signs of wound gaping. The overall number of eyes examined was too small to make definitive conclusions. Implants that deliver corticosteroids (such as the fluocinolone implant), in theory could have higher rates of dehiscence, particularly after exchanges, given the inherent negative effect that corticosteroids have on wound healing. Vitreous hemorrhages were noted in more than half of the specimens. Most occurred in eyes in which multiple procedures were performed. Review of those medical Figure 7. Photomicrograph of a specimen treated with an apoptosis terminal deoxynucleotidyl transferase mediated deoxyuridine triphosphate nick-end labeling (TUNEL) assay. Blue staining indicates cells under apoptosis (arrows); loss of ciliary muscle cells is seen (original magnification, 200). 784

6 Srivastava et al Pathology of the Ganciclovir Implants records found that most of the hemorrhages were noted in the immediate postoperative period. There were some cases without observation of a vitreous hemorrhage clinically. The hemorrhages were mild for the most part and may have been associated with poor wound closure. However, hemorrhage should still be considered a complication that can delay wound healing and can induce and promote vitreal fibrous growth and membrane formation. The placement of the strut or strut imprint also was examined. Clearly, a strut that spans the pars plana and sclera is not ideal because the potential for poor wound closure increases. This may increase the possibility of infection and may provoke an inflammatory response to the strut embedded in the pars plana and sclera. Most eyes had the strut limited to the inner two thirds of the sclera, although only one half of these eyes were limited to the inner one third. The implants for the most part were placed within the pars plana. In 5 eyes, the border of pars plana and pars plicata was the site of implantation and the pars plicata was the site in 1 additional eye. In these eyes, more changes were noted at the adjacent ciliary body structure, including more severe hyalinization as well as fibrosis of the ciliary muscle. The potential negative effects of improper placement of the implant within the eye either at the incorrect site or with too long of a strut stresses the importance of proper surgical technique when inserting these devices. Our series represents the largest study of pathological findings in patients treated with the ganciclovir implant and includes eyes in which either implant exchanges were performed or multiple implant sites were present. Anand et al 9 examined 7 eyes from 5 patients treated with the ganciclovir implant. Light microscopy revealed retinal atrophy and gliosis to varying degrees in all specimens. Their comments regarding the surgical site were limited, but no evidence of an inflammatory reaction was seen. None of the eyes examined had an implant exchange performed. Charles and Steiner 8 reported on 4 eyes from 3 patients with CMV retinitis treated with the ganciclovir implant. In 1 eye, the suture tab entered full-thickness sclera, in another eye, the tab protruded subconjunctivally, and in the last 2 eyes, the implants were entirely in the vitreous. Only 1 of the 4 eyes examined had an implant replaced. Fibrous ingrowth from the implant site was noted in all 4 specimens, and minimal granulomatous inflammation related to the nylon suture anchoring suture was found. Finally, al-yousuf et al 10 reported on 2 eyes from 1 patient with CMV retinitis treated with ganciclovir implants. Neither of these eyes underwent implant exchanges. The incision sites were found to be well-healed without fibrosis around either site. Foreign body giant cell reactions were observed near the suture site, but no other signs of inflammation were noted. The findings noted in these other small series match well with our findings; the device is well tolerated overall and controls the retinitis effectively. Fibrous ingrowth from the implant site seems to be a benign occurrence, although it may lead to traction on the peripheral retina. Microscopic vitreous hemorrhage is present in many eyes, especially those that have undergone multiple procedures, and it is unclear whether more severe hemorrhage could lead to more severe fibrous ingrowth. Surgical technique remains an important variable, because improper placement can lead to poor wound closure or ciliary body changes related to more anterior placement of the implant. Poor wound closure occurred rarely and only in eyes that underwent implant exchanges and additional vitreous surgery. The next generations of implant devices are smaller than the ganciclovir implant and require a smaller incision into the pars plana. 6,7 Given the findings in this study, expectations for the next generation of implant devices should include low rates of wound dehiscence and inflammation and excellent tolerance at the incision site. References 1. Martin DF, Parks DJ, Mellow SD, et al. Treatment of cytomegalovirus retinitis with an intraocular sustained-release ganciclovir implant: a randomized controlled clinical trial. Arch Ophthalmol 1994;112: Musch DC, Martin DF, Gordon JF, et al, Ganciclovir Implant Study Group. Treatment of cytomegalovirus retinitis with a sustained-release ganciclovir implant. N Engl J Med 1997; 337: Martin DF, Dunn JP, Davis JL, et al, International AIDS Society-USA. Use of the ganciclovir implant for the treatment of cytomegalovirus retinitis in the era of potent antiretroviral therapy: recommendations of the International AIDS Society- USA. Am J Ophthalmol 1999;127: Jabs DA, Bartlett JG. AIDS and ophthalmology: a period of transition. Am J Ophthalmol 1997;124: Ashton P, Blandford DL, Pearson PA, et al. Review: implants. J Ocul Pharmacol 1994;10: Jaffe GJ, Yang CS, Wang XC, et al. Intravitreal sustainedrelease cyclosporine in the treatment of experimental uveitis. Ophthalmology 1998;105; Jaffe GJ, Ben-nun J, Guo H, et al. Fluocinolone acetonide sustained drug delivery device to treat severe uveitis. Ophthalmology 2000;107: Charles NC, Steiner GC. Ganciclovir intraocular implant: a clinicopathologic study. Ophthalmology 1996;103: Anand R, Font RL, Fish RH, Nightingale SD. Pathology of cytomegalovirus retinitis treated with sustained release intravitreal ganciclovir. Ophthalmology 1993;100: al-yousuf NH, Dhillon B, Ironside J. Ganciclovir implant: clinicopathological study [letter]. Eye 2000;14: Buggage RR, Chan CC, Matteson DM, et al. Apoptosis in cytomegalovirus retinitis associated with AIDS. Curr Eye Res 2000;21: Walton RC, Wilson J, Chan CC. Metastatic choroidal abscess in the acquired immunodeficiency syndrome [letter]. Arch Ophthalmol 1996;114: Holland GN. New issues in the management of patients with AIDS-related cytomegalovirus retinitis. Arch Ophthalmol 2000;118: Martin DF, Ferris FL, Parks DJ, et al. Ganciclovir implant exchange: timing, surgical procedure, and complications. Arch Ophthalmol 1997;115: Morley MG, Duker JS, Ashton P, Robinson MR. Replacing ganciclovir implants. Ophthalmology 1995;102:

7 Ophthalmology Volume 112, Number 5, May MacCumber MW, Sadeghi S, Cohen JA, Deutsch TA. Suture loop to aid in ganciclovir implant removal. Arch Ophthalmol 1999;117: Boyer DS, Posalski J. Potential complication associated with removal of ganciclovir implants. Am J Ophthalmol 1999;127: Bayley AC. Surgical Pathology of HIV infection: lessons from Africa. Br J Surg 1990;77: Smith KJ, Skelton HG III, Yeager J, et al. Histologic features of foreign body reactions in patients infected with human immunodeficiency virus type 1. J Am Acad Dermatol 1993; 28: