Isolated diastolic hypotension a risk factor for heart failure

Isolated diastolic hypotension (IDH) is an independent risk factor for heart failure similar in magnitude to isolated systolic hypertension (ISH), researchers reported.

To determine whether IDH, defined as diastolic blood pressure less than 60 mm Hg and systolic blood pressure equal to or greater than 100 mm Hg, was a risk factor for heart failure, researchers reviewed data from the Cardiovascular Health Study (CHS), a National Heart, Lung, and Blood Institute-funded, population-based, prospective study of Medicare-eligible community dwelling adults.

After excluding people with existing heart failure, missing blood pressure data or systolic blood pressure less than 100 mm Hg, researchers studied 5,376 participants with and without treated hypertension. The primary outcome was physician-diagnosed heart failure reported in patient charts. Secondary outcomes were all-cause mortality and other incident cardiovascular events. Results appeared online Sept. 26 at Hypertension.

During more than 12 years of median follow-up, 751 (14%) had IDH. Heart failure developed in 25% and 20% of matched participants with and without IDH, respectively (hazard ratio [HR] when IDH was compared with no-IDH, 1.33; [95% confidence interval [CI], 1.10 to 1.61]; P=0.004). The multivariable-adjusted HR for IDH-associated heart failure in prematch participants with systolic blood pressure more than 140 mm Hg was 1.43 (95% CI, 1.16 to 1.77; P=0.001). All-cause mortality occurred in 49% and 44% of matched participants with and without IDH, respectively (HR associated with IDH, 1.12; [95% CI, 0.98 to 1.28]; P=0.096). IDH had no significant association with acute myocardial infarction, angina pectoris, stroke, transient ischemic attack, or peripheral arterial disease.

The authors concluded, “Because intensive lowering of SBP (systolic blood pressure) may not reduce major cardiovascular events, taken together with the findings of the current study, it may be reasonable to keep DBP (diastolic blood pressure) ≥60 mm Hg in older adults with ISH. Future hypertension guidelines need to focus on optimal DBP parameters for older adults receiving antihypertensive therapy.”

An editorial cautioned that the results must be interpreted within the limited definition of IDH used by the researchers. In an elderly population, the cutoff of systolic blood pressure at 100 mm Hg would not be typical, especially with other cardiovascular comorbidities present. Despite the study's limitations, prediction of heart failure based on low diastolic blood pressure warrants further study, the editorial continued. But, “[O]nly clinical trials can establish whether further BP lowering in patients with ISH and low DBP is safe and beneficial in preventing heart failure and other CVD events.”