Despite current assumptions that visit-to-visit variability in a patient’s BP usually does not require treatment, recent research shows that these changes are a strong predictor of stroke, heart failure, angina, and MI, independent of average BP.
Investigators point out that although visit-to-visit variability in BP is common, episodic hypertension tends not to be treated (Lancet. 2010;375:895-905). Researchers analyzed data from 2,006 individuals taking part in various cardiovascular trial cohorts (mean age; 60.3 years) who had had a transient ischemic stroke (TIA) and who underwent BP measurements every four months during follow-up clinic visits.
The patients with the most variation in systolic BP (SBP) over the course of seven clinic visits were six times more likely to have a stroke; those with the highest BP over seven visits were 15 times more likely. Visit-to-visit variability in SBP was more predictive of ischemic stroke than of hemorrhagic stroke.
The investigators reached the following conclusions:
- Visit-to-visit variability in SBP is a powerful predictor of stroke and coronary events independent of mean SBP.
- Maximum SBP is more predictive than is mean SBP.
- Residual variability in SBP after treatment has a poor prognosis.
- Stable hypertension has a better prognosis than does episodic hypertension.
“In secondary prevention after TIA or stroke, for which rates of treatment with antihypertensive drugs are low in routine clinical practice despite good evidence of benefit, the high risk of stroke in patients with episodic hypertension draws attention to the false reassurance of a few normal BP readings,” caution the researchers.
In another SBP-related development, the ACCORD Study Group has learned that bringing SBP to <120 mm Hg as opposed to <140 mm Hg in patients with type 2 diabetes at high risk of cardiovascular events did not reduce the rate of a composite outcome of nonfatal MI, nonfatal stroke, or death from cardiovascular causes. The findings were presented online ahead of print by The New England Journal of Medicine.