intern talk - bp and stroke

Intern TalkNicholas Reynolds

Introduction

•BP increased in stroke and usually decreases spontaneously over time

•BP higher in patients with acute stroke than other acute illnesses

However

•High BP more common in individuals with stroke than general population

•A) High post-stroke BP

•B) Blood pressure variability

Causes for increased post-

stroke HTN•Disturbed autoregulation

•autonomic reactivity

•neuroendocrine factors

•headache, urinary retention, etc.

Troubling point

•The reduction of blood pressure after acute stroke is of no benefit or slight harm: ischemic stroke

•Some benefit: intracerebral hemorrhage

Troubling point

•No clear physiological explanation for these findings

Hypothesis

•Post-stroke hypertension due to recent premorbid increase in blood pressure

Design

•Oxfordshire from 2002 to 2012

•Determine relation between premorbid and acute post-event blood pressure in two stroke subtypes in oxford vascular study

Design

•post-stroke BP

•NIHSS stroke scale >3

•TOAST (Trial of Org 10172 in Acute ischemic stroke treatment) for subtype classification

•European guidelines lowered BP only if >220 mmHg systolic or >120 mmHg diastolic

Analysis•1st event only

•Exclusion: TIA, minor stroke (NIH <3)

•mean 10 yr premorbid BP, highest premorbid BP, visit-visit variability, coefficient of variation, variation independent mean

•log(time scale)

•pre-event to post-event comparision using paired t test

Results•636 eligible patient

•median premorbid BP measurement: 17 (8-31 IRQ)

•positive correlation between number premorbid readings and mean premorbid systolic BP

•mean premorbid systolic BP > ischemic stroke (6.5 mmHg CI 0.5-12)

•mean premorbid visit-visit variability SD 16-89 vs 15-13 mmHg) ischemic vs. hemorrhagic

Results

•most recent premorbid systolic BP in ischemic stroke no greater in period before stroke BUT systolic BP higher in weeks and days before intracranial hemorrhage

Discussion

•premorbid systolic BP increased in patients with intracerebral hemorrhage substantially following stroke

•no difference for ischemic stroke

Discussion

•Post-stroke BP higher than most recent premorbid BP suggesting post-stroke factors leading to rise - cushing’s response, stress

•Odd this not seen in ischemic stroke

Discussion

•Explanation of equivocal findings of BP reduction in ischemic stroke

•Highlight need for long-term BP control especially in prevention of intracerebral hemorrhage

Limitations

•Late presentation

•Post stroke use of antihypertensives

•Measurement error

•no systemic protocol for recording

•exclusions for TIA, minor stroke

•Biphasic intracerebellar hemorrhage peak suggests a mechanism