In people with coronary artery disease, intensive blood pressure control is linked to reduced stroke and heart failure but increased risk for too low blood pressure

Bangalore S, Kumar S, Volodarskiy A, et al. Blood pressure targets in patients with coronary artery disease: observations from traditional and Bayesian random effects meta-analysis of randomised trials. Heart. 2013;99:601-13.

Review question

In people with coronary artery disease, what are the ideal blood pressure targets?

Background

A blood pressure reading consists of 2 numbers, for example 140/90 mm Hg (or 140 over 90). The higher number (systolic BP) is the pressure in the arteries when the heart beats. The lower number (diastolic BP) is the pressure when the heart rests between beats.

Guidelines suggest that the ideal blood pressure for people with hypertension (high blood pressure) is less than 140/90 mm Hg.

Guidelines are often based on the agreement of specialists. It is important to know whether using these recommended blood pressure targets to lower blood pressure actually have an effect on important outcomes such as heart failure or stroke.

How the review was done

The researchers did a systematic review, searching for studies that were published up to February 2012. They found 15 randomized controlled trials with 66,504 patients (average age 57 to 66 years) who had coronary artery disease but no heart failure or heart attack.

In the 15 trials, drugs to reduce blood pressure were compared with placebo or with a different drug. The researchers grouped the study participants by their systolic blood pressure at the end of the trials:

• 140 mm Hg or less (which they called standard blood pressure control) or
• 135 mm Hg or less (which they called intensive  blood pressure control)

The outcomes in these 2 groups were measured after an average of 3 years (ranging from 1 to 6 years).

What the researchers found

Compared with standard blood pressure control (≤ 140 mm Hg), intensive blood pressure control (≤ 135 mm Hg) was linked to

• a 15% reduction in heart failure
• a 10% reduction in stroke
• a 105% increase in the rate of rate of too low blood pressure (which can cause fainting and falls)

Intensive and standard blood pressure control did not differ for death (any cause or due to heart and circulation problems) or for restoring circulation to obstructed blood vessels.

Compared with standard blood pressure control (≤ 140 mm Hg), very intensive blood pressure control (≤ 130 mm Hg) was linked to

• an 8% reduction in heart attacks and chest pain from coronary artery disease
• a 27% reduction in heart failure
• a 17% reduction in stroke

Conclusion

In people with coronary artery disease, intensive control of systolic blood pressure was linked to a small reduction in stroke and heart failure but at the expense of an increased risk of too low blood pressure.

Intensive or very intensive blood pressure control compared with standard blood pressure control (≤ 140 mm Hg) in people with coronary artery disease