Among patients referred to record an AMBP, our study selected a population of suspected and treated hypertensives. We used the Mobil-O-Graph device to measure arterial stiffness, an operator-independent and practicable method. Our study’s main finding is to demonstrate a positively, directly, and moderate association between oPWV and systolic measures of short-time BPV. Also, oPWV showed a correlation with systolic and diastolic OBP and systolic 24-h BP. And with one measurement of central BPV. Multivariate analysis reinforced the link between oPWV and BPV and demonstrated the independence of correlation from OBP and 24-h BP.
BPV definition did not address the strength of association between BPV and arterial stiffness. The daytime-SD and wSD showed the best correlation with oPVW. But these results, when compared to the other BPV index, didn’t were significant. Daytime-SD calculates the distribution readings around a mean [21]. On the other hand, wSD measures BPV using the daytime and nighttime-SD values taking into account and separately quantifying the duration in hours of day and night. This index is independent of day-night BP fluctuations [23].
The measurement of ARV bases it on an average of variations between sequential readings. It short and dynamic changes in BPV. Hence is considered a superior index to measure short-term variability than SDs. This index shows a better correlation with cf-PWV than SDs [10]. Despite that, there is no significant difference between ARV and the other BPV measures in our results. However, we need to emphasize the sample size limited the comparisons of results between different BPV measures.
We infer the better results of SDs in univariate analyses, although no significant, could be based on the method chosen to measure arterial stiffness. Mobil-O-Graph PWV is highly dependent on age and BP values. So, we could presuppose this difference reflects the best association between SDs variability measures and systolic BP. Still, it seems this is not the case because the results showed independence on 24-h BP. Then we can’t explain these differences. And this question claims for other studies.
BPV represents a heterogeneous phenomenon that strongly depends on the estimation method and the period evaluated [24]. Indeed, four previous studies have shown that greater BPV is associated with greater arterial stiffness. Two studies presented limitations due to lack of adjustment for antihypertensive medication or excluded individuals on elevated BP medication [25, 26]. On the Multiethnic Study of Atherosclerosis (MESA) among individuals free of CVD and not taking antihypertensives, the authors showed an association between long-term systolic BPV and a 10-year change in arterial stiffness independent of mean BP level [27]. From data collected in 2 large separate populations, Schilacci et al. [10] demonstrated an independent, moderate relation between short-term variability of 24-h systolic BP and aortic stiffness in hypertension. All of the measures of short-term systolic BPV were consistently and directly related to cf-PWV. ARV of 24-h systolic BP had the most substantial relation with cf-PWV, followed by wSD.
Unlike other studies using cf-PWW [10], the diastolic BPV measures showed a positive correlation with oPWV. However, it was weaker than founded with systolic BPV. Here, after analyzing the changes in results after adjustment. The correlation between oPWV and diastolic BP measures seems dependent on BP values. Similarly, the apparent best association in treated than suspected hypertensive. Also, look dependent on BP differences between groups in treated than suspected hypertensive. Also, look dependent on BP differences between groups.
It is worth commenting on the mechanisms behind this association. Due to the design of our study, we cannot accurately explain this relationship. Aging, BP, and arterial stiffness are closely related. And this association might help explain the results. Nevertheless, the raising in arterial stiffness with aging might be a cause or consequence of raising in BP hence in BPV. Aging increases arterial stiffness, which increases BP, and pressure variability is well established [28, 29].
Baroreceptor function is a significant determinant of BPV. Among young and middle-aged hypertensive individuals. Arterial remodeling and reduce central arterial vessel compliance impairs baroceptor sensitivity. However, a reduction in baroreceptor sensibility accompanies an increase in BP and aging. It was not an independent determinant of the relationship between BPV and baroreceptor function. Thus, more studies are necessary to investigate the causality of this association. Therefore, more tasks are required to examine the basis of this association [30].
Our study presents some force—all PWV measurements performed on the same day, arm, and equivalent cuff size as ABPM records. Mobil-O-Graph device permits a measure operator-independent. Also, we considerer only BPV measures calculate from ABPM. All 24-h BP ambulatory recordings included for analysis fulfilled high-quality criteria. It was important to sort the sample into suspected and treated hypertensive, as demonstrated by a remarkable study [10].
Indeed, the study shows some limitations. Using Mobil-O-Graph to measure PWV also has a negative aspect. Age and BP importantly determine Mobil-O-Graph PWV. We cannot say with certainty if what we measure is arterial stiffness—the size sample limited comparisons of association with oPWV with different BPV measures. And, there were significant differences among demographic and clinical features between the groups studied. Even if the results showed an association between central BPV, we believe that the limited numbers of central measurements underestimated SD central BP, impacting the association’s strength. Our study is cross-sectional, thus precludes conclusions about causality relations between Mobil-O-Graph PWV and BPV.
Estimated cf-PWV calculated from age and media BP predicted major CV events independently of Systematic COronary Risk Evaluation (SCORE), risk factors, and cf-PWV [31]. Mobil-O-Graph permits easily measure PWV and the variability of BP at the same time, using one equipment. It opens the prospect for longitudinal studies to establish how much these measures impact each other, their relationship with target organ injuries, and even CV outcomes. Then, longitudinal studies to set if these measures would use as therapeutic targets in the future.