Evaluation of Risk Factors for Congestive Heart Failure

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The summary below is from the full report titled "Systolic Blood Pressure, Diastolic Blood Pressure, and Pulse Pressure as Predictors of Risk for Congestive Heart Failure in the Framingham Heart Study." It is in the 7 January 2003 issue of Annals of Internal Medicine (volume 138, pages 10-16). The authors are AW Haider, MG Larson, SS Franklin, and D Levy.

What is the problem and what is known about it so far?

Congestive heart failure (CHF) is a potentially fatal condition characterized by weakness of the heart muscle. One of the most common causes of CHF is high blood pressure, which increases tension on the heart muscle and makes the heart work harder to push blood through the arteries. When the heart beats, it pumps blood through the arteries. Doctors can measure the pumping pressures (blood pressure) needed to maintain blood flow in several different ways: by measuring "systolic pressure" (the highest pressure achieved in the arteries as the heart muscle contracts), "diastolic pressure" (the lowest pressure recorded in the arteries as the heart muscle relaxes), and "pulse pressure" (the difference between the systolic and diastolic pressures). Pulse pressure is a measure of stiffness of the arterial walls (or hardening of the arteries). Previous studies have shown that higher systolic and diastolic pressures increase the risk for developing CHF. Researchers have not yet determined whether pulse pressure is an important predictor of CHF in middle-aged people.

Why did the researchers do this particular study?

To find out which blood pressure measurements are most useful in determining the risk for developing CHF.

Who was studied?

2040 people between 50 and 79 years of age with no history of heart disease or high blood pressure. These people were enrolled in a large, long-term study (the Framingham Heart Study).

How was the study done?

The researchers evaluated records of people who were first examined between 1968 and 1973 and who were then followed until 1994 to see who developed CHF and what their blood pressure had been. Factors other than blood pressure that may have affected the development of CHF were considered so that the effects of blood pressure alone (systolic, diastolic, and pulse pressure) could be determined.

What did the researchers find?

234 people developed CHF during the follow-up period. Pulse pressure was strongly related to the occurrence of CHF. Although both systolic and diastolic pressures were also related to CHF, pulse pressure was a stronger predictor than diastolic pressure (but somewhat weaker than systolic pressure).

What are the limitations of the study?

All people enrolled in the study were white; therefore, the results may not apply to other racial and ethnic groups.

What are the implications of the study?

While this study shows that pulse pressure is an important factor in predicting who is at risk for developing CHF, it does not show whether treatment aimed at decreasing stiffness of the arteries can reduce the incidence of CHF.