Proinflammatory effect of abnormal nocturnal blood pressure fall in essential hypertension

Abstract

Recent evidence suggests an association between inflammation and increased atherosclerotic burden. The prognostic significance of abnormal nocturnal blood pressure (BP) fall in essential hypertensive patients (pts) is increasingly recognized. The aim of the present study was to investigate the effect of nocturnal BP fall patterns on inflammatory status, in hypertensive pts. We studied 780 consecutive untreated pts (412 men, 368 women, age 56.8±12.9 years old) with mild to moderate chronic uncomplicated essential hypertension. According to their nocturnal systolic BP fall, pts were classified in extreme dippers (130 pts with >20% nocturnal systolic BP fall), dippers (433 pts with >10% but <20% fall), nondippers (161 pts with >0% but <10% fall) and reverse dippers (56 pts with nocturnal increase of systolic BP). Apart from full biochemical evaluation, inflammatory status was assessed in all pts, by measuring the plasma homocystine (Hcy), serum high-sensitivity C-reactive protein (hsCRP) and serum amyloid-A (SAA) levels. SAA increased from 4.07 mg/l in extreme dippers, to 4.72 in dippers, 5.67 in nondippers and 7.2 mg/l in reverse dippers (p<0.00001). Homocystine and hsCRP levels exhibited as well a significant (p<0.00001) stepwise increase across the groups of nocturnal BP fall patterns (11.22 vs 11.75 vs 13.1 vs 14.7 μmol/l for Hcy and 1.88 vs 1.96 vs 2.64 vs 3.69 mg/l for hsCRP respectively). Extreme dippers did not differ (p=NS) from dippers in regard to any inflammatory marker. In contrast, reverse dippers had significantly increased levels of SAA (p=0.004) and hsCRP (p=0.03) compared to nondippers. Abnormal nocturnal BP fall is associated with increased levels of inflammatory markers in an essential hypertensive population. Reverse dipping status seems to confer an even greater proinflammatory effect than nondipping pattern.