October 2020

NEWS

Research Highlight
Mitral valve prolapse and eye disease: Is there a connection?


by Maxine Lipner Contributing Writer

Though 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 connected 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 hypothesized 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 published cross-sectional trials comparing keratoconus 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 associated 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 expression 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 particularly impacted by such abnormal expression. “I suspect that the Barlow’s variant of degenerative mitral valve prolapse has a stronger association with keratoconus,” Dr. Siordia said.
Co-investigator Jimena Franco, MD, said the connection may have immediate clinical implications 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 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 conditions such as chronic progressive external ophthalmoplegia, retinal vascular occlusions, and open angle glaucoma, she noted.
A separate study2 considered this possible connection to open angle glaucoma. Francesca Nesta Delling, MD, pointed out that the idea for the study came from similar pathophysiology between the two conditions. This involved an accumulation of proteoglycans occurring in both mitral valve prolapse and open angle glaucoma 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 meshwork 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 angle 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, especially if they are older, to ask questions about their vision,” Dr. Delling said.
 

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 association between keratoconus and mitral valve prolapse: A systematic 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

Contact

Delling: Francesca.Delling@ucsf.edu
Franco: siordia.jc@gmail.com
Siordia: Juan.Siordia@bannerhealth.com

Mitral valve prolapse and eye disease: Is there a connection? Mitral valve prolapse and eye disease: Is there a connection?
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