Imai Y
Department of Clinical Pharmacology and Therapeutics, Tohoku University Graduate School of Pharmaceutical Science and Medicine, Seiryomachi, Sendai, Japan.
Blood Press Monit. 1999 Oct;4(5):249-56.
Measurements of ambulatory blood pressure as an adjunct to casual/clinic blood pressure measurements are currently widely used for the diagnosis and treatment of hypertension. There have been many recent reports on the clinical significance of ambulatory blood pressure. The relationship between ambulatory blood pressure level and target-organ damage uniformly demonstrated on a cross-sectional basis that average ambulatory blood pressure is correlated to target-organ damage. The main limitation of cross-sectional studies, however, is the difficulty of drawing inferences about causality from them. We have been monitoring the prognosis of the Ohasama population and reported that ambulatory blood pressure is superior to casual blood pressure for the prediction of mortality. We also observed that the daytime ambulatory blood pressure is a better predictor for cardiovascular mortality in the general population than is the night-time ambulatory blood pressure. It is widely recognized that casual/clinic blood pressure is less representative of the true blood pressure level than is average ambulatory blood pressure. One reason that clinic blood pressure is a poor predictor of prognosis is that clinic blood pressure includes several biases, including the white-coat effect. For determining white-coat hypertension, measurement of blood pressure in a non-medical setting such as ambulatory blood pressure monitoring is indispensable. We examined the prognostic significance for mortality of white-coat hypertension and reversed white-coat hypertension (clinic blood pressure <ambulatory blood pressure). The relative hazard (RH) for the overall mortality for patients with white-coat hypertension was significantly lower than that for true hypertension. Short-term variability of blood pressure has recently attracted attention as a cause of target-organ damage and cardiovascular complications. The findings in cross-sectional studies on the effect of short-term variability of blood pressure are controversial. We observed that short-term variability of blood pressure (variability of blood pressure every 30 min) was independently associated with cardiovascular morbidity. Circadian variation of blood pressure is characterized by a diurnal elevation and a nocturnal decline in blood pressure. In several pathophysiological conditions, however, this nocturnal decline is diminished (non-dipping) and sometimes inverts to nocturnal elevation (inverted dipping). We compared morbidities from strokes for dippers and non-dippers in Ohasama. The incidence of strokes increased with increasing duration of observation for dippers with antihypertensive medication but not in non-dippers with antihypertensive medication. On the other hand, the RH for mortality from cardiovascular diseases increased for non-dippers and inverted dippers. The results suggest that there is a cause-and-effect relationship for dippers and non-dippers. This review demonstrates the independent association between the prognosis of hypertension and each component of ambulatory blood pressure, indicating the prognostic significance of ambulatory blood pressure monitoring.
动态血压测量作为偶测/诊室血压测量的辅助手段，目前广泛应用于高血压的诊断和治疗。近期有许多关于动态血压临床意义的报道。在横断面研究中，动态血压水平与靶器官损害之间的关系一致表明，平均动态血压与靶器官损害相关。然而，横断面研究的主要局限性在于难以从中推断因果关系。我们一直在监测大岛人群的预后情况，并报告动态血压在预测死亡率方面优于偶测血压。我们还观察到，在一般人群中，日间动态血压比夜间动态血压更能预测心血管死亡率。人们普遍认识到，偶测/诊室血压比平均动态血压更不能代表真实血压水平。诊室血压对预后预测不佳的一个原因是，诊室血压存在多种偏差，包括白大衣效应。对于确定白大衣高血压，在非医疗环境中测量血压，如动态血压监测是必不可少的。我们研究了白大衣高血压和反转型白大衣高血压（诊室血压<动态血压）对死亡率的预后意义。白大衣高血压患者总体死亡率的相对危险度（RH）显著低于真性高血压患者。血压的短期变异性最近作为靶器官损害和心血管并发症的一个原因受到关注。关于血压短期变异性影响的横断面研究结果存在争议。我们观察到血压的短期变异性（每30分钟血压变异性）与心血管发病率独立相关。血压的昼夜变化特点是白天血压升高，夜间血压下降。然而，在几种病理生理情况下，这种夜间血压下降会减弱（非勺型），有时会逆转为夜间血压升高（反勺型）。我们比较了大岛地区勺型和非勺型人群的中风发病率。对于服用抗高血压药物的勺型人群，中风发病率随观察时间延长而增加，但服用抗高血压药物的非勺型人群则不然。另一方面，非勺型和反勺型人群心血管疾病死亡率的RH增加。结果表明，勺型和非勺型之间存在因果关系。本综述表明高血压预后与动态血压各组成部分之间存在独立关联，表明动态血压监测的预后意义。
