Table 7 BRS measures and arterial stiffness parameters

Cunha et al. [34]

1997

BRS sequence method

cf-PWV

Continuous measurements of blood pressure for 20 min in the supine position to calculate beat-to-beat SBP, DBP and RRI;

Spontaneous breathing

PWV between the carotid and femoral arteries was determined by the foot-to-foot method

Significant negative correlation between PWV and BRS in hypertensive subjects

–

Lantelme et al. [36]

2002

BRS sequence method (BRS-s)

BRS alpha-index (BRS-a)

cf-PWV

Beat-to-beat measurements of SBP and RRI for 10 min in the supine position and 5 min in the standing position; Spontaneous breathing

PWV between the carotid and femoral arteries was determined by the foot-to-foot method

Significant negative correlation between both supine and standing BRS-s (not BRS-a) and PWV in hypertensive subjects

Significant increase in SBP, reduction in RRI, BRS-s and BRS-a from supine to standing

Siegelova et al. [38]

2004

BRS spectral method

Pulse pressure Carotid IMT

Continuous measurements of blood pressure for 5 min in the supine position;

metronome-controlled breathing 0.33 Hz

B-mode ultrasonography was performed in the supine position on both the right and left common carotid artery

Average carotid IMT was determined from 5 measurements

No specific analysis on the association between BRS measures and carotid IMT or pulse pressure was reported

Treated hypertensives with a higher pulse pressure are older, have a lower gain of the baroreflex and have a larger IMT

Labrova et al. [39]

2005

BRS spectral method

BRSf

Carotid IMT

Continuous measurements of RR-intervals, beat-to-beat SBP and DBP in the sitting position at rest during a 5 min period;

metronome-controlled breathing 0.33 Hz

B-mode ultrasonography was performed in the supine position on both the right and left common carotid artery

Average carotid IMT was determined from 5 measurements

Significant negative correlation between carotid IMT and both BRS and BRSf in the whole group but not in hypertensive group

Decreased BRS and BRSf in hypertensive patients

Positive correlation between age and IMT; negative correlation between age and BRS and BRSf in the whole group. However, age-related BRS was significantly weakened in the hypertensives due to an age-dependent prolongation of mean RRI

Novakova et al. [40]

2005

BRS spectral method

BRSf

Carotid IMT

Continuous measurements of RR-intervals, beat-to-beat SBP and DBP in the sitting position at rest during a 5 min period; metronome-controlled breathing 0.33 Hz

B-mode ultrasonography was performed in the supine position on both the right and left common carotid artery

Average carotid IMT was determined from 5 measurements

Significant negative association between BRS, BRSf and carotid IMT in the whole group (both measurements in a period of 1 year)

Greater IMT, decreased BRS and BRSf in hypertensive patients compared to normotensive subjects (both measurements in a period of 1 year, 2004–2005)

Labrova et al. [41]

2005

BRS spectral method

BRSf

Carotid IMT

Continuous measurements of RR-intervals, beat-to-beat SBP and DBP in the sitting position at rest during a 5 min period;

metronome-controlled breathing 0.33 Hz

B-mode ultrasonography was performed in the supine position on both the right and left common carotid artery

Average carotid IMT was determined from 5 measurements

Significant negative correlation between carotid IMT and BRS and BRSf in the whole group but not in hypertensive group

Greater IMT, decreased BRS and BRSf in hypertensive patients compared to normotensive subjects

Chan et al. [42]

2005

BRS sequence method

TAC

RRI and SBP were derived from continuous ECG and non-invasive BP measurements, respectively, at two timepoints:

(i) baseline: while receiving conventional hemodialysis (\(\ge\) 18 h after the session); and

(ii) 2 months after a stable dose of nocturnal hemodialysis (\(\ge\) 4 h after the session)

Spontaneous breathing

TAC (SV/PP)

Significant positive correlation between BRS and TAC in hypertensive subjects with ESRD

Following conversion from conventional hemodialysis to nocturnal hemodialysis, mean HR remains unaffected, SBP and DBP decreased, while BRS and TAC increased

Honzikova et al. [43]

2006

BRS spectral method

Carotid IMT

Continuous measurements of RR-intervals, beat-to-beat SBP and DBP in the sitting position at rest during a 5 min period; metronome-controlled breathing 0.33 Hz

B-mode ultrasonography was performed in the supine position on both the right and left common carotid artery

Average carotid IMT was determined from 5 measurements

Significant negative correlation between carotid IMT and BRS in the normotensive and whole groups, but not in hypertensive group

BRS was negatively correlated with age and IMT in normotensive subjects and in the whole group, but not in hypertensive subjects

Michas et al. [44]

2012

BRS alpha-index

cf-PWV

Continuous measurements of RR-intervals, beat-to-beat SBP and DBP in the sitting position at rest during a 5 min period;

metronome-controlled breathing 0.25 Hz

PWV between the carotid and femoral arteries was determined by the foot-to-foot method

No separate association analysis was reported between the two study groups

Significant negative correlation between PWV and BRS in the whole group (normotensives and hypertensives)

Hypertensive patients were significantly older, had higher PWV and lower BRS than normotensive subjects

Celovska et al. [45]

2012

BRS sequence method

BRS spectral method

BRSf

Carotid IMT

Continuous measurements of RRI, SBP and DBP for three sequential periods of 5 min each in the supine position;

metronome-controlled breathing 0.33 Hz

mean of the maxima at 4 sites of both common carotid artery and carotid bulb

Significant negative correlation between all BRS measures and carotid/carotid bulb IMT in hypertensive with stroke patients in comparison with stroke-free hypertensives

The higher the grade of hypertension, the lower the BRS/BRSf values

Significant association between reduced BRS and increased SBP, PP and carotid IMT in hypertensives with stroke

Okada et al. [47]

2013

BRS sequence method

(assessed by averaging the values of the slope of the linear correlation between RRI and beat-by-beat SBP during the two VM (phase IV))

cf-PWV

Continuous measurements of HR and BP during these tests:

(i) 6 min of spontaneous breathing;

(ii) two VM at 40 mmHg for 20 s with 5 min apart and

(iii) 60° upright tilt for 10 min (MSNA data were collected during the last 3 min of tilting)

Spontaneous breathing

PWV between the carotid and femoral arteries was determined by the foot-to-foot method

No specific analysis on the association between BRS measures and cf-PWV was reported

Higher cf-PWV and lower sympathetic BRS in hypertensive patients compared to normotensive subjects, but similar morning HR increase and cardiovagal BRS between both groups.

Upright sympathetic BRS was smaller and %TPR/%MSNA by 60° HUT was higher in hypertensive subjects with greater morning surge than those with lesser morning surge. No difference in supine or upright MSNA between the groups.

Significant positive correlation between morning surge and cf-PWV and sympathetic BRS in hypertensive subjects only.

Sympathetic BRS, but not %TPR/%MSNA, was correlated with cf-PWV in hypertensive subjects.

Celovska et al. [49]

2017

BRS Sequence method; BRS Spectral method

Carotid IMT

Continuous measurements of RRI, SBP and DBP for three sequential periods of 5 min each in the supine position; metronome-controlled breathing 0.33 Hz

Measured on the far wall of common carotid artery along 1 cm long section proximal to the carotid bulb

Mean of 3 single measurements at the side (left and right common carotid) with greater IMT was calculated

No specific analysis on the association between BRS measures and carotid IMT was reported

Significant negative correlation between spectral BRS, sequence BRS and systolic BP as well as mean BP in hypertensives

Prehypertensive and hypertensives with critical BRS ≤ 5 ms/mmHg have significantly increased carotid and carotid bulb IMT