Introduction:
Elevated arterial blood pressure (BP) increases the risk of intracerebral hemorrhage after intravenous (IV) thrombolysis with tPA in acute ischemic stroke (AIS). While arterial BP is usually monitored using intermittent oscillometric measurements with an upper arm cuff, the vascular unloading technique (VUT) provides non-invasive continuous BP monitoring with a finger cuff.
Hypothesis:
We hypothesized that VUT monitoring is feasible in AIS patients receiving IV tPA, is comparable to the standard technique, and allows detection of BP peaks that might be missed in oscillometric BP monitoring.
Methods:
We performed an interim analysis of an ongoing prospective method comparison study. AIS patients were simultaneously monitored over 24 h following IV tPA bolus using VUT and contralateral oscillometric BP assessment every 30 min.
Results:
We present interim data from 15 out of 24 AIS (4 m, 11 f; aged 72.5±14.9 y, mean±SD) receiving IV tPA. Nominal significance level was set to 0.029 in accordance with Pocock’s rule. Missing data were less than 5% for both techniques. There was a positive correlation between VUT and oscillometric BP assessment (Pearson’s correlation coefficient r=0.91, p<0.001 for systolic BP; and r=0.88, p<0.001 for diastolic BP). Bland-Altman analysis confirmed this agreement (figure 1). The mean difference between VUT and oscillometric BP measurements was 9.4±6.1 mmHg for systolic, and 4.5±3.0 mmHg for diastolic BP (p=n.s.). Peaks (systolic BP>180 or diastolic BP>110 mmHg) were detected by VUT monitoring (at least one episode≥5 min) in 12 patients, and by oscillometric BP assessment (≥one time point of measurement) in 7 patients (p<0.01).
Conclusions:
Our interim data suggest that VUT-based BP monitoring is feasible in AIS patients receiving IV tPA, and might be more sensitive than intermittent oscillometric BP assessment in detecting potentially harmful blood pressure peaks.
Figure 1:
Bland Altman plot
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