The Importance of Pulse Pressure

Summarized by Robert W. Griffith, MD
November 30, 2005

Introduction

Pulse pressure is the change in blood pressure seen during a contraction of the heart; formally, it's the systolic pressure minus the diastolic pressure, measured in mmHg. Usually, the resting pulse pressure in healthy adults is about 40 mmHg. Various studies have shown that a high pulse pressure is linked to an increased risk of heart attack, stroke, and heart failure. These studies have mostly been confined to populations from a single country, and it's not necessarily clear if the results can be generalized to all people worldwide. New results from the so-called Seven Countries Study, which have been published in the Archives of Internal Medicine, help answer this point.

What was done

The Seven Countries Study began in 1958. During the first 6 years 12,763 men aged 40 to 59 who lived in the United States, Japan, Finland, the Netherlands, Italy, Greece, and former Yugoslavia were enrolled. For this analysis, those with cardiovascular disease at enrollment - about 8.5% - were excluded.

The men were seen every 5 years for the next 25 years. Information was collected on coronary heart disease (heart attack, angina pectoris, sudden coronary death, heart failure, and cardiac rhythm irregularities), stroke, and cardiovascular mortality.

The age at death, physical activity level, smoking status, blood pressure, body mass index (BMI) and blood lipid levels were also established.

What was found

Compared with age, physical activity, total cholesterol, BMI, and smoking status, all baseline blood pressure measurements were the best predictors of cardiovascular mortality. The pulse pressure proved to be one of the best predictors.

The average pulse pressure of those enrollees who were still alive at the final exam was 52 mmHg, compared with 58, 61, and 56 mmHg for those who had died from coronary heart disease, stroke, or other cardiovascular disease, respectively.

In general, the findings were the same for each country; the Japanese participants, however, had the lowest systolic and diastolic blood pressures, but the highest pulse pressures.

For every 10 mmHg rise in pulse pressure, there was a 15% increase in the risk for coronary heart disease and a 32% increase in the risk for death from a stroke.

Why Is Pulse Pressure More Predictive?

The systolic pressure is due to the resistance offered by the major arteries to the force exerted by the heart's contraction; the diastolic pressure is the resistance offered by the much smaller blood vessels during the time when the heart is relaxed. The authors of the study point out that, as people age, systolic pressure rises more than diastolic pressure - presumably due to decreased elasticity of the larger arteries - so that the pulse pressure rises, too. It's the decreased elasticity of the arteries (associated with atherosclerosis) that is dangerous - especially for stroke. An increased pulse pressure is thus a good measure of the inelasticity of the arteries.

There's a condition called isolated systolic hypertension (ISH) commonly seen in seniors, in which the pulse pressure is increased due to a rise in the systolic pressure with an unchanged diastolic pressure. The risks associated with this form of high blood pressure confirm the relevance of the pulse pressure as a predictive value. So always check both blood pressure numbers and do a little math, to make sure you keep all three numbers under control.

Source

• The relation between pulse pressure and cardiovascular mortality in 12,763 middle-aged men from various parts of the world. PDB. Panagiotakos, KD. Kromhout , MA. Menotti ,  et al., Arch Intern Med, 2005, vol. 165, pp. 2142--2147

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