Excessive lowering of BP causes more harm than good

Clinical Question

Can aggressive lowering of blood pressure in patients with coronary artery disease be dangerous?

Bottom Line

Lower is not always better. Despite a push toward lower blood pressure in many populations, bad outcomes (mortality, myocardial infarction, and stroke) are increased in patients with coronary artery disease (CAD) if their blood pressure consistently remains lower than 70 mmHg diastolic. (LOE = 1b)

Reference

Messerli FH, Mancia G, Conti CR, et al. Dogma disputed: can aggressively lowering blood pressure in hypertensive patients with coronary artery disease be dangerous? Ann Intern Med 2006;144:884-893.  [PMID:16785477]

Study Design

Cohort (prospective)

Funding

Industry

Setting

Outpatient (any)

Synopsis

Research has hinted at a J-shaped response to lowering blood pressure: As blood pressure is lowered, mortality and morbidity decrease, to a point, after which further lowering is associated with higher mortality and morbidity. Common guidelines and conventional wisdom do not take this risk into account and advocate various degrees of aggressive blood pressure control on the basis of other risk factors. This study is an analysis of the results of a study comparing the effectiveness of verapamil and trandolapril in hypertensive patients with CAD. In this analysis, the investigators evaluated the relationship between average diastolic blood pressure and the primary outcome of all-cause death, nonfatal stroke, and nonfatal myocardial infarction in the 22,576 patients enrolled in the study. The patients in this study were treated and monitored for a median 2.7 years and mortality and morbidity rates were not different between the 2 treatments. Blood pressure was divided into 10 mmHg increments and this outcome was evaluated at each level of control. As in other research, the J-curve is present in these data, associated with decreases in diastolic blood pressure. The best results were a diastolic blood pressure between 80 mmHg and 90 mmHg. A diastolic blood pressure between 70 mmHg and 80 mmHg was associated with slightly, but not significantly, increased bad outcomes, though patients with blood pressures of lower than 70 mmHg experienced bad outcomes at the same rate as those with readings higher than 100 mmHg.