Retinal vascular disease is commonly caused by retinal artery or vein occlusions (RAO/RVO), which are blockages in the arteries or veins of the eye, specifically the retina. These blockages can eventually lead to a stroke if left untreated.
Although there appears to be a connection between patients with retinal artery or vein occlusions and atrial fibrillation (a common type of irregular heartbeat), atrial fibrillation is not listed among the current risk factors for retinal artery occlusions. Both conditions are associated with certain risk factors for cardiovascular disease, however. These include high blood pressure and diabetes.
A possible theory that links these two conditions comes from the embolisms, a blockage-causing substance that gets stuck inside a blood vessel, often related to retinal artery occlusions. It is said the blockages are too large to cause RAO, but they may cause atrial fibrillation, and as atrial fibrillation is often asymptomatic, it would explain the underlying cause of RAO when embolisms are present.
This led to the formation of a new study, aimed at confirming the association between atrial fibrillation and RAO and RVO. Participants were selected who had not previously been diagnosed with atrial fibrillation. The hypothesis of the study was that patients with RAO or RVO would demonstrate a higher risk of atrial fibrillation development.
The researchers used a national health database from Denmark to identify patients with retinal occlusions between 1997 and 2011. The participants were followed until the time that atrial fibrillation occurred, they passed away, or the study ended. The study included 1,368 participants in the experimental group and 6,840 controls.
The results of the study showed that patients with RAO showed a significantly higher rate of atrial fibrillation than the control group. This difference was not consistent in patients with RVO, however. There was no significant increase in the prevalence of atrial fibrillation in the patients with retinal vein occlusions when compared to the control group.
“Given that AF may have been undiagnosed at the time of RAO, this strengthens the hypothesis that AF may in some cases be the underlying cause of RAO,” write the researchers. The association observed in this study is only a correlational one, however, rather than a causational one. There is still a clear indication that atrial fibrillation may be the underlying cause of retinal artery occlusions and these results should not be ignored in the literature on this topic.
While it is important for potentially silent atrial fibrillation to be identified in the course of treating RAO patients, the researchers remain clear that further research is required before treatment plans are altered. Atrial fibrillation is often treated with oral anticoagulant medication and the effects of anticoagulants are unknown in relation to the treatment of retinal artery occlusions or retinal vein occlusions. There should be additional causational studies performed to confirm the relationship between atrial fibrillation and RAO, as well as additional studies to determine the short and long-term effects of treating atrial fibrillation in RAO patients.
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