Abstract
Purpose :
To describe choroidal infarction after ophthalmic artery chemotherapy in patients who had at least one mutated copy of the methylenetetrahydrofolate reductase (MTHFR) gene and received inhaled nitrous oxide with anesthesia during ophthalmic artery chemosurgery (OAC).
Methods :
Single center retrospective review of pediatric patients with advanced retinoblastoma (diagnosed as International Classification Groups D and E) who received OAC and developed choroidal infarcts. All patients had at least one mutated copy of the MTHFR gene (mutations in either the C677T or A1298C alleles on chromosome 1p at position 36.22) and received inhaled nitrous oxide induction anesthesia (between 5 to 10 minutes duration) during the preceding OAC. Indirect ophthalmoscopy, RetCam digital photography, ocular coherence tomography (OCT) and in some of the patients, fluorescein angiography (FA) was used to describe fundus findings.
Results :
Six advanced retinoblastoma patients ages 10 to 58 months (3 males, 3 females) experienced choroidal infarcts within the one-month period after OAC in which nitrous oxide induction was used for the procedure. All 6 patients had abnormalities in MTHFR: two were homozygous for the C677T mutation of the MTHFR gene, two were heterozygous for C677T, one was heterozygous for A1298C, and one was heterozygous for both C677T and A1298C. In all 6 patients, indirect ophthalmoscopy and fundus photography showed marked disturbance of the retinal pigment epithelium and OCT confirmed marked thinning of the choroid. Follow-up time for these patients ranged from 6 to 49 months (median 14.5 months).
Conclusions :
Choroidal infarction in eyes treated with OAC developed in children who were both deficient in at least one working allele of the MTHFR gene (heterozygous or homozygous) and received nitrous oxide induction anesthesia during ophthalmic artery chemosurgery.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.