Study Demonstrates Prognostic Value of Pupil Area for All‐Cause Mortality in Patients With Heart Failure

August 11, 2020—The European Society of Cardiology (ESC) announced the publication of a study of the prognostic value of the pupil area for all-cause mortality in patients with heart failure. The study, by Kohei Nozaki et al, is available online ahead of print in ESC Heart Failure.

According to ESC, one cause of worsening heart failure is disturbed function of the body’s autonomic system, which is typically evaluated by measuring changes in heart rate. However, this method is ineffective in patients with atrial fibrillation. Pupil area is another way to assess autonomic function and has been used in patients with Parkinson’s disease and diabetes. This study examined whether pupil area could predict prognosis in patients with heart failure.

As summarized in the ESC announcement, the study was composed of 870 patients hospitalized for acute heart failure from 2012 to 2017. The average age was 67 years, and 37% of patients were women.

Pupil area was measured in both eyes at least 7 days after hospital admission. For the test, patients put on goggles and waited 5 minutes for their eyes to adapt to the dark. Photos were then taken of the eyes. Because the autonomic system is affected by time of day, patients were tested at a standard time (between 9:00 am and 12:00 pm).

Patients were divided into a small pupil area group and a large pupil area group according to whether their measurement was below or above the median (16.6 mm²). The primary endpoint was all-cause mortality, and the secondary endpoint was readmission because of heart failure.

The investigators found that during a median follow-up of 1.9 years, 131 patients died and 328 were rehospitalized because of heart failure. Compared to the large pupil area group, patients in the small pupil area group had a significantly poorer survival rate and significantly higher rate of readmission for heart failure.

After adjusting for other factors that could affect prognosis, such as body mass index and kidney function, patients with a large pupil area had a 28% lower risk of all-cause mortality and an 18% reduced risk of readmission due to heart failure compared to patients with a small pupil area. Large pupil area was consistently linked with favorable survival regardless of age, sex, and the presence of either normal heart rhythm or atrial fibrillation, concluded the investigators.

“Our results suggest that pupil area is a novel way to identify heart patients at elevated risk of death or hospital readmission,” commented study investigator Kohei Nozaki in the ESC press release. “This provides an opportunity to intervene and improve outlook. Finding better ways to pinpoint which patients are more likely to be readmitted or die is crucial.”

Dr. Nozaki, who is with the Department of Rehabilitation at Kitasato University Hospital in Kanagawa, Japan, continued, “Pupil area can be obtained rapidly, easily, and noninvasively. Our study indicates that it could be used in daily clinical practice to predict prognosis in patients with heart failure, including those who also have atrial fibrillation. Patients with a small pupil area (eg, < 16.6 mm²) could be prioritized for cardiac rehabilitation with physical activity, which has been reported to improve autonomic function.” Mr. Nozaki noted that pupil area cannot be used in patients with severe retinopathy or other eye diseases.