Variations in Your High Blood Pressure Carry the Risk of Stroke

People are well aware of the two blood pressure readings – the upper or systolic, and the lower or diastolic.  The systolic blood pressure is the maximum pressure exerted in the arteries when the heart contracts, and the diastolic is the pressure in the arteries when the heart is at rest between contractions.  The risks associated with raised blood pressure are usually associated with the systolic or the diastolic reading.  However, recent publications in the journal Lancet show that it’s variability in the systolic pressure that may carry the most risk a for stroke.    

In the first study, there were 4 groups of 2,000 people, each of whom had had a TIA (transient ischemic attack or mini-stroke).  Analyses showed that there was an increased risk in those with greater visit-to-visit variability in systolic pressure.  Those with the greatest variation in systolic pressure and those with the highest pressure readings were 6- and 15-times more likely to have a stroke.  Patients on an antihypertensive drug that showed less systolic variability (a calcium-channel blocker) had a lower stroke risk than those on a beta-blocker.   

The second study was a meta-analysis of 389 controlled trials; it found lower variability with calcium-channel blockers and diuretics, and increased variability with ACE inhibitors, angiotensin-receptor blockers, and beta blockers.  In these analyses, a similar relationship was shown between the degree of systolic pressure variability and the likelihood of stroke. 

These studies provide what one investigator calls “compelling results”;  however, they have provoked one expert to recommend further studies before there’s a rush to switch hypertensive patients to calcium-channel blockers, rather than ACE-inhibitors or ARBs.  Maybe the important thing is for physicians (and patients) to pay attention to occasional high systolic readings, rather than dismissing them as “episodic hypertension” or “aberrant readings”.