Blood pressure variability is more important than blood pressure level in determination of end-organ damage in rats.

OBJECTIVE

This study was designed to determine how important a novel risk factor of elevated blood pressure variability (BPV) is in the determination of end-organ damage by comparison with the classic risk factor of a high blood pressure (BP) level.

METHODS AND RESULTS

The effects of haemodynamics on cardiovascular morphology were evaluated by univariate and multivariate regression analysis in two different rat models with an enlarged distribution of haemodynamics. In male sham-operated and sinoaortic-denervated Wistar-Kyoto rats and spontaneously hypertensive rats (n = 34), BPV was more important than BP in cardiac and renal damage and aortic hypertrophy. BPV and BP had independent effects, explaining 59.4% of the variation in damage to these organs. In male (n = 44) and female (n = 46) F1 hybrids of Sprague-Dawley rats and spontaneously hypertensive rats, the greater importance of BPV than BP was further demonstrated in left ventricular hypertrophy, glomerular damage and aortic hypertrophy. The phenomenon was more evident in females than males for cardiovascular hypertrophy. BPV and BP or BPV alone had independent effects, explaining 46.9% (male) or 37.5% (female) of the variation in damage to these organs.

CONCLUSION

BPV is a more critical determinant than BP level for cardiac damage, renal lesions and aortic hypertrophy in rats, strongly suggesting the significance of BPV control for the protection of these organs.