Ambulatory blood pressure monitoring and stroke: more questions than answers.

Abstract

The increasing use of ambulatory blood pressure monitoring (ABPM) devices in the investigation of hypertension has allowed detailed study of the circadian rhythm of blood pressure variability, the assessment of resistant hypertension, and the syndrome of “white coat” hypertension. The relevance of ABPM to target-organ damage and the complications of hypertension, such as heart attacks and strokes, has only recently gained prominence. There are more than 30 cross-sectional studies that have linked ABPM to hypertensive target-organ damage, including left ventricular hypertrophy (LVH),1 2 microalbuminuria,3 hypertensive retinal changes, and cerebrovascular disease.4 The majority of these studies have consistently reported that patients with an absent or reduced fall in blood pressure at night (referred to as “nondippers”) have more severe target-organ damage, including LVH5 and cerebrovascular disease,4 6 when compared with patients who demonstrate a normal nocturnal fall in blood pressure. For example, Verdecchia et al,7 in a prospective cohort of over 1100 hypertensive patients, reported higher mortality rates both in nondippers and “reverse dippers” and higher cardiovascular morbidity rates in female nondippers compared with dippers.8 In addition, Yamamoto et al9 recently reported that progressive cerebrovascular disease, including silent ischemic lesions and symptomatic stroke, was associated with a reduced nocturnal blood pressure fall in patients with a history of lacunar infarction. In a cross-sectional study of patients admitted with acute stroke (ictus <12 hours), Lip at al10 reported that such patients could generally be classed as nondippers, with higher blood pressures recorded using ABPM (but not using casual manual measurements) in black/Afro-Caribbean patients and also in patients with hemorrhagic stroke. These studies therefore suggest the potential usefulness of ABPM in epidemiological, cohort, or cross-sectional studies and the assessment of ethnic differences, stroke subtypes, and prognosis. A nondipper status …