Blood Pressure in Acute Ischemic Stroke: When More May Indeed Be More
Abstract & Commentary
Synopsis: Blood pressure reduction in the first 24 hours of stroke onset is independently associated with poor outcome after 3 months.
Source: Oliveira-Filho J, et al. Neurology. 2003;61:1047-1051.
In the outpatient setting, treatment of blood pressure is a key component of stroke prevention. For patients who have already suffered a stroke, treatment with angiotensin-converting enzyme (ACE) inhibitors is warranted, even in the absence of hypertension. The management of blood pressure in the acute phase of ischemic stroke is, however, less well understood. In fact, it has been advocated by some that the pharmacologic elevation of blood pressure may augment perfusion to the ischemic penumbra and improve stroke outcome. Many clinicians have anecdotal experience that keeping the head of a stroke patient’s bed flat can produce improvements in their neurological exam, immediately reversible by sitting them up.
Oliveira-Filho and colleagues present data from 115 patients, evaluated and treated within the first 24 hours after stroke onset. There was an odds ratio of 1.89 in favor of an adverse outcome associated with each 10% decrease in systolic blood pressure. This finding occurred independent of treatment with anti-hypertensive medications (in 59% of patients), but was correlated with higher admission blood pressures.
Similar trends were present for diastolic blood pressure, which did not reach statistical significance. The population was representative of stroke in the general population as classified by anatomic location (Oxfordshire Class) and by etiology (TOAST criteria). Not surprisingly, in addition to blood pressure, outcomes were also predicted by stroke severity (according to the NIH Stroke Scale). Blood pressure decreases were defined by the difference between the admission blood pressure and the lowest measured value within the first 24 hours of presentation.
Comment by Alan Z. Segal, MD
Acute hypertension in the throes of a stroke is likely part of the body’s own catecholamine-driven protective response system to cerebral ischemia. Blood pressure guidelines for acute stroke advise that pharmacological lowering not be done unless blood pressures exceed 220/120. As Oliveira-Filho et al note, many patients were treated with blood pressures below this range. Although the data suggest that it was spontaneous decreases in blood pressure rather than medications that were of harm, the implication remains that blood pressures may have been overtreated in this group of patients. While theoretical concerns of hemorrhagic conversion or increased edema due to marked blood pressure elevation remain, it is clear that if blood pressure is to be treated at all for stroke patients, it should be done with short-acting, easily controllable agents such as labetalol or nicardipine.
Dr. Segal is Assistant Professor, Department of Neurology, Weill-Cornell Medical College; Attending Neurologist, New York Presbyterian Hospital, New York, NY.
Blood pressure reduction in the first 24 hours of stroke onset is independently associated with poor outcome after 3 months.
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