Eyeworld

26 | EYEWORLD | OCTOBER 2020 Contact Delling: Francesca.Delling@ucsf.edu Franco: siordia.jc@gmail.com Siordia: Juan.Siordia@bannerhealth.com by Maxine Lipner Contributing Writer changes in these patients may be due to the development of keratoconus," she said, adding that these patients should be educated about the connection and get an exam. In addition to keratoconus, mitral valve prolapse might be linked to other ocular con- ditions such as chronic progressive external ophthalmoplegia, retinal vascular occlusions, and open angle glaucoma, she noted. A separate study 2 considered this possible connection to open angle glaucoma. Francesca Nesta Delling, MD, pointed out that the idea for the study came from similar pathophysiol- ogy between the two conditions. This involved an accumulation of proteoglycans occurring in both mitral valve prolapse and open angle glau- coma patients. "In mitral valve prolapse, this accumulation leads to expansion of the middle layer of the valve," she said. In glaucoma this accumulation occurs in the trabecular mesh- work where it causes obstruction of the outflow of the aqueous humor. Investigators in this retrospective cohort study found that patients with mitral valve prolapse were at a 1.88-fold increased risk of having open angle glaucoma. Still, this is relative risk. "If you look at the absolute risk, it is only 10.17 per 10,000 person years," she said. "It's not that high if you look at the absolute number of people who develop open angle glaucoma." At this point, screening mitral valve prolapse patients for glaucoma would not be called for, Dr. Delling said, adding that screening open an- gle glaucoma patients for mitral valve prolapse would be premature. Dr. Delling speculated that medications given for one of these conditions may impact the other. ACE inhibitors commonly given to prolapse patients have been shown to reverse tissue degeneration in vitro, she pointed out, adding that if it is proven to be effective for slowing down prolapse, it may also reduce the incidence of glaucoma. She hopes that physicians keep in mind the possible link. "I think that if you have a patient with mitral valve prolapse, it's reasonable, espe- cially if they are older, to ask questions about their vision," Dr. Delling said. T hough mitral valve prolapse is a heart diagnosis, it could be an important factor for an ophthalmologist to keep in mind. The condition seems to be linked to keratoconus, open angle glaucoma, as well as other possible ophthalmic maladies. A recent study indicated that patients with keratoconus also tend to have mitral valve prolapse, according to Juan Siordia, MD. 1 Both of these conditions are associated with collagen defects. "They are both connect- ed by deficiencies in lysyl oxidase, impeding collagen crosslinking and therefore weakening the structure," Dr. Siordia said. "They also both tend to be present in systemic syndromes such as Ehlers-Danlos syndrome, Marfan syndrome, and Down syndrome." Investigators hypothe- sized that keratoconus and mitral valve prolapse were not only connected but also that therapies for one could be used for the other. For the study, investigators evaluated pub- lished cross-sectional trials comparing kera- toconus and mitral valve prolapse prevalence rates. "We looked for prevalence of mitral valve prolapse in patients with keratoconus and vice versa," Dr. Siordia said. He determined that there indeed appeared to be a connection. "The overall finding is that these diseases are associat- ed with one another," he said. Dr. Siordia theorized that the connection could be the result of collagen crosslinking deficiencies, as well as a lack of functional lysyl oxidase. In addition, he thinks abnormal expres- sion of glycosaminoglycan in impacted mitral valve tissue further links the two diseases. A type of mitral valve prolapse that presents at an earlier age, known as Barlow's disease, is partic- ularly impacted by such abnormal expression. "I suspect that the Barlow's variant of degenera- tive mitral valve prolapse has a stronger associa- tion with keratoconus," Dr. Siordia said. Co-investigator Jimena Franco, MD, said the connection may have immediate clinical im- plications for ophthalmologists because patients with mitral valve prolapse could be at increased risk for keratoconus. "The clinician should be aware that the development of any new visual Mitral valve prolapse and eye disease: Is there a connection? About the doctors Francesca Nesta Delling, MD Assistant Professor of Medicine University of California, San Francisco Jimena Franco, MD Cornea/External Disease and Refractive Surgery Assistant Instructor University of Texas Southwestern Medical Center Dallas, Texas Juan Siordia, MD Resident, Internal Medicine Banner – University Medical Center Tucson Tucson, Arizona References 1. Siordia JA, Franco JC. The asso- ciation between keratoconus and mitral valve prolapse: A system- atic review. Curr Cardiol Review. 2020;16:147–152. 2. Chiang SJ, et al. Association between mitral valve prolapse and open-angle glaucoma. Heart. 2015;101:609–615. Relevant disclosures Delling: None Franco: None Siordia: None N RESEARCH HIGHLIGHT EWS

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