Comparison of simultaneous measurements of blood pressure by tail-cuff and carotid arterial methods in conscious spontaneously hypertensive and Wistar-Kyoto rats.

We determined the validity of systolic blood pressure (SBP) measured by tail-cuff blood pressure (TCBP) with direct intra-arterial measurements. In conscious, restrained Wistar-Kyoto (WKY) and spontaneously hypertensive rats (SHR), carotid artery (CA) BP and TCBP were simultaneously measured. In both WKY and SHR strains, highly significant correlations between CABP and TCBP were found and Bland-Altman analyses showed no bias when the two methods were compared. The limits of agreement between CABP and TCBP in WKY and SHR were wide and reproducibility of pressure measurements by either technique was poor, with some evidence for strain-dependent differences. Pressure measurements made over short time frames, however, showed close agreement between CABP and TCBP. Acetylcholine-induced reductions in pressure were equivalently detected by tail-cuff and direct arterial measurement in both strains but angiotensin II-induced pressure elevations were over-estimated by tail-cuff in SHR. Telemetered SBP measurements in conscious rats were highly variable in a strain-dependent manner.