Structural changes in small blood vessels may precede the development of severe high blood pressure, findings from the Blue Mountains Eye Study in Australia indicate.

Previous reports have suggested that structural changes in blood vessels in the retina of the eye precede the development of severe high blood pressure, senior author Dr. Paul Mitchell from the University of Sidney and colleagues note. However, whether such changes alone predict high blood pressure was unclear.

To investigate, the researchers monitored blood pressures in 3,654 older subjects living in two postal areas west of Sydney. Photographs of the retina were also taken at the beginning of the study and analyzed for blood vessel narrowing. Of the 2,335 subjects who returned for examination 5 years later, the researchers focused on 1,319 who had normal or just slightly elevated blood pressure when they entered the study.

The researchers’ findings are published in the current rapid access issue of Hypertension: Journal of the American Heart Association.

Nearly 30 percent of subjects developed severe high blood pressure. After factoring in various risk factors, the researchers found that the subjects with the narrowest retinal vessels were 2.6-times more likely to develop severe high blood pressure than those with the widest vessels. Even after taking into account considering the initial blood pressure status, this association remained statistically significant.

These retinal signs appear to predict development of severe high blood pressure, independent of other risk factors such as age, gender, weight, smoking, blood sugar levels, and blood pressure status at the start of the study, Mitchell commented in a statement.

This suggests that among individuals who have similar blood pressure levels, those who also have narrowed blood vessels in the retina have a greater risk of developing high blood pressure.

SOURCE: Hypertension, August 10, 2004.