A Predictive Model for Temporal Artery Biopsy in the Setting of Suspected Giant Cell Arteritis: A Validation Study.

PURPOSE: A previously published predictive model based on threshold parameters for erythrocyte sedimentation rate, c-reactive protein, and platelet count demonstrated that 40% of patients who underwent biopsy may not have required it. The current study was performed to evaluate the model's performance on an independent data set. METHODS: This is a retrospective consecutive series of patients undergoing temporal artery biopsy (TAB) in a single health region in Canada. The model was applied to a multicenter cohort of patients undergoing TAB by a variety of surgical services. A centralized pathological database serving multiple institutions and surgical services was used to identify patients undergoing TAB. RESULTS: Over a 7-year period, patients undergoing TAB were identified via a central pathological database. Those who had concurrent illnesses which would likely affect erythrocyte sedimentation rate, c-reactive protein, and platelet count, patients on steroids for >2 weeks by the time of biopsy, and those with missing serum markers were excluded. The previously developed model was applied to the 222 patients enrolled. The model correctly identified 29% of patients with a pretest probability of 0% for a positive biopsy and 9% with a pretest probability of 100%, suggesting that in total, 38% of patients could have avoided TAB. CONCLUSION: The results of this independent data set support the previously published predictive formula. Utilizing a simple, clinically applicable predictive model of the pretest probabilities, approximately 38% of TAB currently being performed may be avoided. The results suggest that evaluation with a prospective multicentre study would be appropriate.

LONG-TERM OUTCOMES FOR OPTIC DISK PIT MACULOPATHY AFTER VITRECTOMY.

PURPOSE: To evaluate the efficacy of pars plana vitrectomy for congenital optic disk pit maculopathy with various adjuvant techniques, including gas tamponade, internal limiting membrane peel, and temporal optic disk endolaser in a multicenter study with long-term follow-up. METHODS: A retrospective chart review was performed to identify eyes that underwent surgical repair for congenital optic disk pits and serous macular detachment with or without macular retinoschisis from four retinal centers across Canada from 2003 to 2013. Data collected included surgeries performed, preoperative and postoperative vision, central retinal thickness, and presence or absence of subretinal fluid. Optical coherence tomography was used to define anatomical success (i.e., foveal reattachment). RESULTS: Thirty-two eyes of 32 patients with optic disk pits and serous macular detachments were identified that had undergone surgical repair. All eyes underwent pars plana vitrectomy and induction of posterior vitreous detachment if one was not present. Additional procedures performed on occasion included internal limiting membrane peel (n = 8), temporal optic disk pits endolaser (n = 7), and gas tamponade (air, C3F8 or SF6; n = 31). After vitrectomy surgery, foveal attachment was achieved in 26 of 32 eyes (81.3%). The average number of surgeries required was 1.4 ± 0.6, with a maximum of 3 vitrectomies (n = 2). Mean change in best-corrected visual acuity was -0.47 ± 0.54 logMAR units, which corresponds to approximately 5 lines of visual improvement (P < 0.001). Median time to reattachment was 416 days. Preoperative vision, preoperative symptom days, and age were not associated with postoperative reattachment. Similarly, internal limiting membrane peel and temporal endolaser were not associated with postoperative reattachment, nor was there a difference between air and SF6 and C3F8 gas tamponade. Elevated preoperative central retinal thickness was associated with a lower chance of postoperative reattachment (P = 0.007) and was also the best prognostic indicator of success (P = 0.039). CONCLUSION: Vitrectomy for macular detachment due to optic disk pit has good long-term success and results in an improvement in visual acuity. However, adjuvant techniques such as internal limiting membrane peel and temporal endolaser may not improve outcomes, nor does there seem to be a difference between short- and long-acting gases. Patients should be made aware that it can take more than a year and multiple surgeries to achieve foveal reattachment and that increased baseline central retinal thickness is a poor prognostic sign.