Higher blood pressure variations are associated with worse clinical outcomes in patients with stroke compared with those without stroke, according to study findings published in the journal Neurology.
Blood pressure variability has been linked to worse outcomes in patients with stroke and has also been acutely observed in a variety of illnesses. It is unclear whether this variance represents a diseased state, or a modifiable risk factor that can be targeted for intervention. As such, researchers investigated the incidence of blood pressure variability in patients with vs without stroke in an intensive care unit (ICU), as well as comparing outcomes.
The researchers conducted a retrospective analysis on adult patients admitted to the ICU at Beth Israel Deaconess Medical Center (BIDMC) from 2001 and 2012. Data was collected on individuals admitted to the ICU with the following International Classification of Diseases 9th Edition (ICD-9) diagnoses:
- ischemic stroke,
- intracerebral hemorrhage (ICH),
- subarachnoid hemorrhage (SAH),
- acute myocardial infarction,
- pulmonary embolism, sepsis,
- congestive heart failure,
- gastrointestinal bleed, or
To limit outlier readings, those with less than 10 blood pressure measurements were excluded.
The primary outcome of the study was death, occurring either in-hospital or after transfer out of the ICU. Secondary outcomes included favorable discharges, which consisted of discharge to a person’s home, acute rehabilitation, hospice or skilled nursing facility.
A total of 11,333 individuals were included in the analytic sample, that of which 2248 had stroke-related diagnoses and 9085 were admitted for nonstroke related diagnoses.
Compared with nonstroke admissions, patients with stroke were more likely to have higher blood pressure variability and minimum arterial pressure (MAP) readings (a measure of volume instability).
Overall, a higher blood pressure variability was linked to higher odds of in-hospital death, for all conditions with the exception of congestive heart failure. It also decreased odds of a favorable discharge among all conditions, with statistical significance in those with ischemic stroke, ICH, SAH, acute myocardial infarction, sepsis, and gastrointestinal bleed.
This finding was most notable amongst those with SAH and ICH; the highest tertile of blood pressure deviation was associated with an odds ratio of in-hospital death of 7.7 (95% CI, 3.0-19.9) in those with SAH and the lowest odds of a favorable discharge of 0.2 (95% CI, 0.16-0.4) in those with ICH.
Study limitations included a lack of generalizability, as this study was conducted at a single-center and differential misclassification was also plausible, as the researchers were reliant on ICD-9 codes for diagnosis.
“Higher BPV was associated with higher odds of in-hospital death and unfavorable discharge destination in stroke patients following adjustment for other markers of critical illness, though attenuated when accounting for markers of potential clinician-driven blood pressure goals, particularly in those with SAH,” the researchers wrote. They concluded, “Research is needed to better delineate the mechanisms underlying our findings, as well as determining how specific stroke features such as location and size affect BPV and its relation with outcomes.”