Manning LS, Mistri AK, Potter J, Rothwell PM, and Robinson TG. Short-Term Blood Pressure Variability in Acute Stroke: Post Hoc Analysis of the Controlling Hypertension and Hypotension Immediately Post Stroke and Continue or Stop Post-Stroke Antihypertensives Collaborative Study Trials. Stroke. 2015
This was a retrospective analysis of standard deviation in the BP variability of acute ischemic stroke patients from the landmark CHHIPS and COSSACS trials. It looked at the effect on death and disability (mRS 4 and above) at 2 weeks.
CHIPPS
Controlling Hypertension and Hypotension Immediately Post Stroke trial had 179 pts and controlled BPs <36 hours from stroke onset (95.5% patients included)
COSSACS
Continue Or Stop post-Stroke Antihypertensives Collaborative Study had 763 pts and controlled BP <48 hours from stroke onset (92.55% patients included)
They found that BP variability had no significant impact on death and disability at 2 weeks.
Limitations of this study:
The CHIPPS and COSSACs studies had different BP management strategies where the former involved active BP lowering and the latter involved simply holding or continuing home BP meds. The treatment periods and severity of patients’ strokes (median NIHSS 4 vs 9) were also different.
The assessment of death and disability at 2 weeks is an unusually short window as the standard time point for analysis in most stroke studies is 3 months. This may even be too early a window as stroke patients continue to recover well beyond this time period. A recent publication on the 12 month outcomes of IMS-III showed that patients with severe strokes did have less disability after thrombectomy whereas no difference was found at the original 3 month mark.
Another limitation of this study is that it lumps all strokes together. bp variability may very well be an important prognostic indicator in patients who have proven large vessel stenosis or occlusion and a subgroup analysis might demonstrate that. The 2 studies were not well matched by vascular territory of incident stroke, but both studies were underpowered to begin with.
The study takes casual cuff measurements and doesn’t measure true variability as an arterial line would. but then again, even if a study were to show that A-line BP variability measurements predicted outcome, it probably wouldn’t be cost effective or practical to put an A-line in every stroke patient.
The study population was mostly white and not well matched between COSSACS and CHHIPS for this demographic as well as several others.
How does this study change my practice? No effect.
