How important is blood pressure variability?

Abstract

Arterial blood pressure (BP) is a continuous variable, with a physiology characterized by significant variability stemming from the complex interaction among haemodynamic factors, neuronal reflexes, as well as hormonal, behavioural, and environmental stimuli. The homoeostatic response accounts for the physiologic variability in BP in normotensive individuals, which is more evident in hypertensive patients. Blood pressure variability is a complex phenomenon, which could be classified in various types: very short term (beat to beat), short term (during 24 h), mid-term (day by day), long term (<5 years), and very long term (>5 years). Accurate measurement of BP variability represents a complex and often controversial endeavour, despite several methodological approaches are available. Albeit a prognostic significance has been demonstrated for some indicators of BP variability, the clinical significance of this measurement is still uncertain. In fact, none of the indicators presently available for BP variability, including early morning BP rise, substantially affects, and redefines, the cardiovascular risk of the hypertensive patient, over and beyond the mere BP values. Accordingly, in defining the cardiovascular risk, the focus should be on the absolute BP values, which remain the most relevant risk factor, and the one more susceptible to modification with both non-pharmacologic and pharmacologic treatment.

Progression of Beat-to-Beat Blood Pressure Variability Despite Best Medical Management

“…However, these methods require repeated assessments and the magnitude of the prognostic value of BPV compared with mean BP alone is uncertain, limiting their current use in clinical practice. 16 Beat-to-beat blood pressure variability can be assessed in a single clinic visit, is cross-sectionally associated with clinical markers of cardiovascular risk, is associated with similar underlying physiological processes as day-to-day BP variability 11 and predicts outcome after acute stroke 17 and the risk of recurrent stroke and cardiovascular events. 10 This study now demonstrates that beat-to-beat BPV progresses significantly over time despite excellent risk factor control, predicts loss to follow-up, and that this progression parallels progression of arterial stiffness.…”

Aging steepens the slope of power spectrum density of 30-minute continuous blood pressure recording in healthy human subjects

“…Although the very short-term BPV analysis has the potential for stratifying the CV risk as shown by several animal studies, the predictive power is not as high as daily BPV assessed by 24-h ABPM. The major reason for the lower predictive power of very short-term BPV may be the lack of clinical evidence [ 41 , 42 ]. Since the very short-term BPV analysis requires continuous BP measurement devices, the development of those devices will change this situation.…”

Long-term BP variability: open questions in clinical practice

“…Averaging BP accounts for the phenomenon of BP variability, which constitutes an additional feature of BP phenotype. However, the prognostic importance of mean BP is as solid as the clinical significance of its variability is uncertain [ 1 ].…”

“…In fact, despite reflecting the interplay among the same biological/intrinsic determinants as of mean BP, including neurohormonal, humoral, metabolic, anatomic, environmental, and genetic factors, the definition and clinical meaning of BP variability remain controversial [ 1 ]. The impact of external modifiers of the biological determinants of BP profile over time (i.e.…”

“…The impact of external modifiers of the biological determinants of BP profile over time (i.e. medications use and compliance [ 2 ]), as well as methodological issues (optimal timing, measurement setting and procedure) have so far prevented the scientific community from coming to a shared definition of reference ranges for BP variability, with the only exception of day-to-night BP changes expressed by the phenomenon of “dipping” [ 1 ].…”