Study Urges Cautious Blood Pressure Lowering for Heart Disease Patients

Authors of a new study urge a cautious approach to using blood pressure-lowering treatment for heart disease patients.

In an effort to study the connection between achieved blood pressure and cardiovascular outcomes in patients with coronary artery disease and hypertension, researchers analyzed data from 22,672 patients with stable coronary disease from 45 countries. Participants had been enrolled in the CLARIFY registry between November 26, 2009 and June 30, 2010 and treated for hypertension. Before each event, the authors averaged and categorized systolic and diastolic blood pressures into 10 mm Hg increments. The primary outcome was the composite of cardiovascular death, myocardial infarction, or stroke. Hazard ratios were estimated with multivariable adjusted Cox proportional hazards models, using the 120–129 mm Hg systolic blood pressure and 70–79 mm Hg diastolic blood pressure subgroups as reference.
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Increased systolic blood pressure of 140 mm Hg or more and diastolic blood pressure of 80 mm Hg or more were each associated with increased risk of cardiovascular events after a median follow-up of 5 years. Systolic blood pressure of less than 120 mm Hg was also associated with increased risk for the primary outcome. Likewise, the authors note that diastolic blood pressure of less than 70 mm Hg was associated with an increase in the primary outcome.

The findings underscore "the need to be cautious when treating hypertension in patients with established coronary artery disease, and avoid lowering blood pressure below a threshold of 120 mm Hg systolic or 70 mm Hg diastolic," says principal investigator Philippe Gabriel Steg, MD, a professor of cardiology at Université Paris.

These results also "emphasize the importance of the methods for blood pressure measurement," adds Steg. "We know that routine 'casual' office [blood pressure] can substantially overestimate the resting blood pressure, compared, for example, to the very sophisticated measures used in the SPRINT trial, by as much as 15 mm Hg,"

However, "we cannot estimate reliably by how much in an individual patient," continues Steg. "Therefore, if we have any suspicion that we may be close to the threshold values, it may be important to perform the measurements very carefully (5 minutes of rest, discard the first measure, average the next 3) in order to have a reliable measure and avoid 'overtreatment.'"

—Mark McGraw

Reference

Vidal-Petiot E, Ford I, Greenlaw N, et al. Cardiovascular event rates and mortality according to achieved systolic and diastolic blood pressure in patients with stable coronary artery disease: an international cohort study [published online August 2016]. Lancet. doi:http://dx.doi.org/10.1016/S0140-6736(16)31326-5.