Optimal Blood Pressure in Stable CAD Patients
What is the association between achieved blood pressure and cardiovascular outcomes in patients with coronary artery disease (CAD) and hypertension?
The investigators analyzed data from 22,672 patients with stable CAD enrolled from November 2009 to June 2010 in the CLARIFY registry (including patients from 45 countries) and treated for hypertension. Systolic and diastolic blood pressures before each event were averaged and categorized into 10 mm Hg increments. The primary outcome was the composite of cardiovascular death, myocardial infarction, or stroke. Hazard ratios (HRs) 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.
After a median follow-up of 5 years, increased systolic blood pressure ≥140 mm Hg and diastolic blood pressure ≥80 mm Hg were each associated with increased risk of cardiovascular events. Systolic blood pressure <120 mm Hg was also associated with increased risk for the primary outcome (adjusted HR, 1.56; 95% confidence interval, 1.36–1.81) and all secondary outcomes except stroke. Likewise, diastolic blood pressure <70 mm Hg was associated with an increase in the primary outcome (adjusted HR, 1.41 [1.24–1.61] for diastolic blood pressure of 60–69 mm Hg and 2.01 [1.50–2.70] for diastolic blood pressure <60 mm Hg) and in all secondary outcomes except stroke.
The authors concluded that among patients with hypertension and CAD, systolic blood pressure <120 mm Hg and diastolic blood pressure <70 mm Hg were each associated with adverse cardiovascular outcomes, including mortality.
This study reports that low systolic (<120 mm Hg) and low diastolic (<70 mm Hg) blood pressures are associated with an increased risk of cardiovascular events, with a steep J-curve not only for the composite of cardiovascular death, myocardial infarction, or stroke, but also separately for cardiovascular death, all-cause death, myocardial infarction, or hospital admission for heart failure. Along with other available evidence, this study suggests caution when treating patients with CAD aggressively with antihypertensive drugs. Future randomized controlled trials are indicated to confirm the cutoff blood pressure value below which harm exceeds benefit in CAD patients. Clinicians should follow current national guidelines and target a blood pressure <140/90 without lowering it below 120/70 mm Hg.
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