Study: Specific Form of AMD Strongly Associated with Cardiovascular Disease

Patients with a specific type of age-related macular degeneration (AMD) are very likely to have underlying heart damage from heart failure and heart attacks, advanced heart valve disease, or carotid artery disease linked to specific types of strokes, according to a recent study from the New York Eye and Ear Infirmary of Mount Sinai.

This study, which was on November 17 in BMJ Open Ophthalmology, is the first to pinpoint the specific high-risk cardiovascular and carotid artery diseases that are connected to the eye disease. The results may lead to enhanced screening in order to save vision, identify undiagnosed heart disease, and prevent harmful cardiovascular events.

“For the first time, we have been able to connect these specific high-risk cardiovascular diseases to a specific form of AMD, the one with subretinal drusenoid deposits (SDDs),” lead author R. Theodore Smith, MD, PhD, Professor of Ophthalmology at the Icahn School of Medicine at Mount Sinai, said in Mount Sinai news release. “This study is the first strong link between the leading cause of blindness, AMD, and heart disease, the leading cause of death worldwide. Furthermore, we also have strong evidence for what actually happens: the blood supply to the eye is directly diminished by these diseases, either by heart damage that diminishes blood supply throughout the body, or from a blocked carotid artery that directly impedes blood flow to the eye. A poor blood supply can cause damage to any part of the body, and with these specific diseases, the destroyed retina and leftover SDDs are that damage. Retinal damage means vision loss, and can lead to blindness.”

One major form of early AMD consists of small yellow cholesterol deposits called drusen, which form under a part of the retina called the retinal pigment epithelium (RPE). They can deprive the retina of blood and oxygen, which could result in blindness. The production of drusen can be slowed down with the right vitamin intake. Subretinal drusenoid deposits (SDDs), the other main type of early AMD, are less well known and can only be found via sophisticated retinal imaging.

These deposits, which accumulate above the RPE and immediately below the light-sensitive retinal cells, are made up of a distinct type of cholesterol and are where the damage and loss of vision take place. SDDs have no known treatments.

Initially, Dr. Smith and a group of Mount Sinai researchers discovered that SDDs were more prevalent in people with cardiovascular illness or stroke. The results of the groundbreaking study were published in Retina's July edition. By examining a broader patient population and building on the earlier research, this current study pinpoints the precise severe forms of carotid artery disease and heart disease that resulted in the SDDs of AMD.

Researchers analyzed the eyes of 200 AMD patients with retinal imaging to determine which patients had SDDs. Patients provided information on their history of cardiovascular illness in a questionnaire. 97 of the 200 patients had SDDs, while 103 just had drusen. Of the 200, 47 had significant cardiac disease (19 had heart damage from heart failure or heart attack, 17 serious valve disease, and 11 stroke stemming from the carotid artery). 86 percent or 40 out of the 47 had SDDs. The 153 AMD patients who did not have these serious illnesses, however, had 57 SDDs (43 percent). The researchers came to the conclusion that AMD patients were nine times more likely to suffer SDDs than patients without these severe cardiovascular illnesses and strokes.

“This work demonstrates the fact that ophthalmologists may be the first physicians to detect systemic disease, especially in asymptomatic patients,” says co-investigator Richard B. Rosen, MD, Chief of the Retina Service for the Mount Sinai Health System. “Detecting SDDs in the retina should trigger a referral to the individual’s primary care provider, especially if no previous cardiologist has been involved. It could prevent a life-threatening cardiac event.”

The next step for researchers is to concentrate on patients in cardiology and neurology clinics in order to further examine various degrees of cardiovascular and carotid disease and assess that potential relationship between disease severity to AMD with SDD.