After intracranial hemorrhage, does blood pressure variability matter beyond the average?

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Survivors of intracranial hemorrhage (ICH) face an increased risk of major adverse cardiovascular and cerebrovascular events (MACCE), including recurrent stroke and myocardial infarction. Researchers investigated whether long-term blood pressure variability is a risk factor for MACCE after ICH independently of average blood pressure.

They analyzed data from prospective ICH cohort studies at Massachusetts General Hospital and the University of Hong Kong. They measured long-term, visit-to-visit blood pressure variability using each participant's coefficient of variation. They explored determinants of systolic and diastolic blood pressure variability and used survival analysis models to examine their associations with MACCE.

Among 1,828 ICH survivors followed for a median of 46.2 months, 166 had recurrent ICH, 68 had ischemic strokes and 69 had myocardial infarctions. Black participants had higher blood pressure variability (coefficient +3.8, standard error 1.3), as did Asian participants (coefficient +2.2, standard error 0.4).

Long-term systolic blood pressure variability was independently associated with recurrent ICH (subhazard ratio 1.82; 95% confidence interval 1.19–2.79), ischemic stroke (1.62; 1.06–2.47) and myocardial infarction (1.54; 1.05–2.24). Average blood pressure during follow-up did not modify the association between long-term systolic blood pressure variability and MACCE.

The researchers concluded that long-term blood pressure variability is a potent risk factor for recurrent hemorrhage, ischemic stroke and myocardial infarction after ICH, even among survivors whose hypertension is well controlled. They said the findings support the hypothesis that controlling both average blood pressure and its variability after ICH is required to minimize MACCE incidence.