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American Journal of Physiology.... Oct 2023Peripheral artery disease (PAD) refers to obstructed blood flow in peripheral arteries typically due to atherosclerotic plaques. How PAD alters aortic blood pressure and...
Peripheral artery disease (PAD) refers to obstructed blood flow in peripheral arteries typically due to atherosclerotic plaques. How PAD alters aortic blood pressure and pressure wave propagation during exercise is unclear. Thus, this study examined central blood pressure responses to plantar flexion exercise by investigating aortic pulse wave properties in PAD. Thirteen subjects with PAD and 13 healthy [age-, sex-, body mass index (BMI) matched] subjects performed rhythmic plantar flexion for 14 min or until fatigue (20 contractions/min; started at 2 kg with 1 kg/min increment up to 12 kg). Brachial (oscillometric cuff) and radial (SphygmoCor) blood pressure and derived-aortic waveforms were analyzed during supine rest and plantar flexion exercise. At rest, baseline augmentation index ( = 0.0263) and cardiac wasted energy ( = 0.0321) were greater in PAD due to earlier arrival of the reflected wave ( = 0.0289). During exercise, aortic blood pressure (aMAP) and aortic pulse pressure showed significant interaction effects ( = 0.0041 and = 0.0109, respectively). In particular, PAD had a greater aMAP increase at peak exercise ( = 0.0147). Moreover, the tension time index was greater during exercise in PAD ( = 0.0173), especially at peak exercise ( = 0.0173), whereas the diastolic time index ( = 0.0685) was not different between the two groups. Hence, during exercise, the subendocardial viability ratio was lower in PAD ( = 0.0164), especially at peak exercise ( = 0.0164). The results suggest that in PAD, the aortic blood pressure responses and myocardial oxygen demand during exercise are increased compared with healthy controls.
Topics: Humans; Arterial Pressure; Blood Pressure; Peripheral Arterial Disease; Heart Rate; Exercise; Pulse Wave Analysis
PubMed: 37486070
DOI: 10.1152/ajpregu.00303.2022 -
Internal and Emergency Medicine Dec 2015The renal resistive index (RRI) is measured by Doppler sonography in an intrarenal artery, and is the difference between the peak systolic and end-diastolic blood... (Review)
Review
The renal resistive index (RRI) is measured by Doppler sonography in an intrarenal artery, and is the difference between the peak systolic and end-diastolic blood velocities divided by the peak systolic velocity. The RRI is used for the study of vascular and renal parenchymal renal abnormalities, but growing evidence indicates that it is also a dynamic marker of systemic vascular properties. Renal vascular resistance is only one of several renal (vascular compliance, interstitial and venous pressure), and extrarenal (heart rate, aortic stiffness, pulse pressure) determinants that combine to determine the RRI values, and not the most important one. RRI cannot always be considered a specific marker of renal disease. To summarize from the literature: (1) hydronephrosis, abdominal hypertension, renal vein thrombosis and acute kidney injury are all associated with an acute increase in interstitial and venous pressure that determine RRI values. In all these conditions, RRI is a reliable marker of the severity of renal damage. (2) The hemodynamic impact of renal artery stenosis can be assayed by the RRI decrease in the homolateral kidney by virtue of decreasing pulse pressure. However, renal diseases that often coexist, increase renal vascular stiffness and hide the hemodynamic effect of renal stenosis. (3) In transplant kidney and in chronic renal disease, high RRI values (>0.80) can independently predict renal and clinical outcomes, but systemic (pulse pressure) rather than renal hemodynamic determinants sustain the predictive role of RRI. (4) Higher RRI detects target renal organ damage in hypertension and diabetes when renal function is still preserved, as a marker of systemic atherosclerotic burden. Is this the fact? We attempt to answer.
Topics: Blood Flow Velocity; Blood Pressure; Heart Rate; Humans; Kidney; Kidney Diseases; Renal Artery; Ultrasonography, Doppler; Vascular Resistance; Vascular Stiffness
PubMed: 26337967
DOI: 10.1007/s11739-015-1289-2 -
Blood Pressure Dec 2022Hypertension diagnosis is one of the most common and important procedures in everyday clinical practice. Its applicability depends on correct and comparable... (Review)
Review
Hypertension diagnosis is one of the most common and important procedures in everyday clinical practice. Its applicability depends on correct and comparable measurements. Cuff-based measurement paradigms have dominated ambulatory blood pressure (BP) measurements for multiple decades. Cuffless and non-invasive methods may offer various advantages, such as a continuous and undisturbing measurement character. This review presents a conceptual overview of recent advances in the field of cuffless measurement paradigms and possible future developments which would enable cuffless beat-to-beat BP estimation paradigms to become clinically viable. It was refrained from a direct comparison between most studies and focussed on a conceptual merger of the ideas and conclusions presented in landmark scientific literature. There are two main approaches to cuffless beat-to-beat BP estimation represented in the scientific literature: First, models based on the physiological understanding of the cardiovascular system, mostly reliant on the pulse wave velocity combined with additional parameters. Second, models based on Deep Learning techniques, which have already shown great performance in various other medical fields. This review wants to present the advantages and limitations of each approach. Following this, the conceptional idea of unifying the benefits of physiological understanding and Deep Learning techniques for beat-to-beat BP estimation is presented. This could lead to a generalised and uniform solution for cuffless beat-to-beat BP estimations. This would not only make them an attractive clinical complement or even alternative to conventional cuff-based measurement paradigms but would substantially change how we think about BP as a fundamental marker of cardiovascular medicine.
Topics: Arterial Pressure; Blood Pressure; Blood Pressure Determination; Blood Pressure Monitoring, Ambulatory; Humans; Pulse Wave Analysis
PubMed: 36184775
DOI: 10.1080/08037051.2022.2128716 -
American Journal of Hypertension May 2022Heart failure (HF) is frequent in patients with diabetes mellitus (DM), and early detection improves prognosis. We investigated whether analysis of brachial blood...
BACKGROUND
Heart failure (HF) is frequent in patients with diabetes mellitus (DM), and early detection improves prognosis. We investigated whether analysis of brachial blood pressure (BP) in daily practice can identify patients with DM and high risk for subsequent HF, as defined by brain natriuretic peptide (BNP) >50 pg/ml.
METHODS
3,367 outpatients with DM without a history of cardiovascular disease were enrolled in a prospective study.
RESULTS
Age (mean ± SD) was 56 ± 14 years, 57% were male, 78% had type 2 DM, and HbA1C was 7.4 ± 1.4%. A history of hypertension was recorded in 43% of patients and uncontrolled BP was observed in 13%. BNP concentration (mean ± SD) was 21 ± 21 ng/l and 9% of patients had high risk of incident HF. Brachial pulse pressure (PP) was the best BP parameter associated with high risk of incident HF compared with diastolic, systolic, or mean BP (area under the receiver operating characteristic curve: 0.70, 0.65, 0.57, and 0.57, respectively). A multivariate analysis demonstrated that elevated PP was independently associated with high risk of incident HF (odds ratio [95% confidence interval, CI]: 2.1 [1.5-2.8] for PP ≥65 mm Hg). Study of central aortic BP and pulse wave velocity on 117 patients demonstrated that high risk of incident HF was associated with increased arterial stiffness and subendocardial ischemia. After a mean follow-up of 811 days, elevated PP was associated with increased all-cause mortality (hazard ratio [95% CI]: 1.7 [1.1-2.8]).
CONCLUSIONS
Brachial PP is powerful and independent "easy to record" BP parameter associated with high risk of incident HF in diabetic patients.
Topics: Adult; Aged; Blood Pressure; Diabetes Mellitus; Female; Heart Failure; Humans; Hypertension; Male; Middle Aged; Natriuretic Peptide, Brain; Prospective Studies; Pulse Wave Analysis
PubMed: 34969077
DOI: 10.1093/ajh/hpab179 -
Journal of the American College of... Jul 2016
Topics: Blood Pressure; Cardiovascular Diseases; Cardiovascular System; Humans; Hypertension; Risk Factors
PubMed: 27364058
DOI: 10.1016/j.jacc.2016.03.586 -
American Journal of Hypertension Jan 2016In patients with both hypertension and type II diabetes, the systolic blood pressure (SBP) increases linearly with age, while that of diastolic blood pressure (DBP)... (Review)
Review
In patients with both hypertension and type II diabetes, the systolic blood pressure (SBP) increases linearly with age, while that of diastolic blood pressure (DBP) declines curvilinearly as early as age 45, all suggesting the development of increased arterial stiffness. Increased stiffness is an important, independent, and significant risk predictor in subjects with hypertension and diabetes. In patients with both diseases, stiffness assessed at the same mean arterial pressure (MAP) was significantly higher in diabetic patients. Arterial stiffness is related to age, heart rate (HR), and MAP, but in diabetic patients, it also related to diabetes duration and insulin treatment (IT). In the metabolic syndrome (MetSyn), diabetes also acts on the small arteries through capillary rarefaction to reduce the effective length of the arterial tree, increases the reflected pulse wave and thus the pulse pressure (PP). These studies indicate that diabetes and hypertension additively contribute to increased pulsatility and suggest that any means to reduce stiffness would be beneficial in these conditions.
Topics: Arteries; Blood Pressure; Diabetes Mellitus, Type 2; Elasticity; Humans; Hypertension; Risk Factors; Vascular Stiffness
PubMed: 26156872
DOI: 10.1093/ajh/hpv107 -
Investigative Ophthalmology & Visual... Dec 2022To investigate the association of systemic blood pressure and incident primary open-angle glaucoma (POAG) using a large open-access database.
PURPOSE
To investigate the association of systemic blood pressure and incident primary open-angle glaucoma (POAG) using a large open-access database.
METHODS
Prospective cohort study included 484,268 participants from the UK Biobank without glaucoma at enrollment. Incident POAG events were recorded through assessment visits, hospital inpatient admissions, and primary care data. Blood pressure measures included systolic blood pressure (SBP), diastolic blood pressure (DBP), pulse pressure (PP), and mean arterial pressure (MAP). Repeated measurements throughout the study period were analyzed as time-varying covariables. The parameters were modeled as both categorical and continuous nonlinear variables. The primary outcome measure was the relative hazard of incident POAG.
RESULTS
There were 2390 incident POAG events over 5,715,480 person-years of follow-up. Median follow-up was 12.08 years. In multivariable analyses, compared to SBP and PP in the normal range (SBP, 120-130 mmHg; PP, 40-50 mmHg), higher SBP and PP were associated with an increased risk of incident POAG (linear trend P = 0.038 for SBP, P < 0.001 for PP). Specifically, SBP of 130 to 140 mmHg or 140 to 150 mmHg was associated with a 1.16 higher hazard of incident POAG (95% CI, 1.01-1.32 and 1.01-1.33, respectively), whereas a PP of greater than 70 mmHg was associated with a 1.13 higher hazard of incident glaucoma (95% CI, 1.00-1.29). In multivariable models, no statistically significant associations were found for DBP or MAP with incident glaucoma. These findings were similar when blood pressure measures were modeled as continuous variables.
CONCLUSIONS
Higher SBP and PP were associated with an increased risk of incident POAG. Further studies are required to characterize these relationships better.
Topics: Humans; Blood Pressure; Glaucoma, Open-Angle; Prospective Studies; Arterial Pressure; Risk Factors
PubMed: 36469027
DOI: 10.1167/iovs.63.13.3 -
Stroke Apr 2022Increased cerebral arterial pulsatility is associated with cerebral small vessel disease, recurrent stroke, and dementia despite the best medical treatment. However, no...
BACKGROUND
Increased cerebral arterial pulsatility is associated with cerebral small vessel disease, recurrent stroke, and dementia despite the best medical treatment. However, no study has identified the rates and determinants of progression of arterial stiffness and pulsatility.
METHODS
In consecutive patients within 6 weeks of transient ischemic attack or nondisabling stroke (OXVASC [Oxford Vascular Study]), arterial stiffness (pulse wave velocity [PWV]) and aortic systolic, aortic diastolic, and aortic pulse pressures (aoPP) were measured by applanation tonometry (Sphygmocor), while middle cerebral artery (MCA) peak (MCA-PSV) and trough (MCA-EDV) flow velocity and Gosling pulsatility index (PI; MCA-PI) were measured by transcranial ultrasound (transcranial Doppler, DWL Doppler Box). Repeat assessments were performed at the 5-year follow-up visit after intensive medical treatment and agreement determined by intraclass correlation coefficients. Rates of progression and their determinants, stratified by age and sex, were determined by mixed-effects linear models, adjusted for age, sex, and cardiovascular risk factors.
RESULTS
In 188 surviving, eligible patients with repeat assessments after a median of 5.8 years. PWV, aoPP, and MCA-PI were highly reproducible (intraclass correlation coefficients, 0.71, 0.59, and 0.65, respectively), with progression of PWV (2.4%; <0.0001) and aoPP (3.5%; <0.0001) but not significantly for MCA-PI overall (0.93; =0.22). However, PWV increased at a faster rate with increasing age (0.009 m/s per y/y; <0.0001), while aoPP and MCA-PI increased significantly above the age of 55 years (aoPP, <0.0001; MCA-PI, =0.009). Higher aortic systolic blood pressure and diastolic blood pressure predicted a greater rate of progression of PWV and aoPP, but not MCA-PI, although current MCA-PI was particularly strongly associated with concurrent aoPP (<0.001).
CONCLUSIONS
Arterial pulsatility and aortic stiffness progressed significantly after 55 years of age despite the best medical treatment. Progression of stiffness and aoPP was determined by high blood pressure, but MCA-PI predominantly reflected current aoPP. Treatments targetting cerebral pulsatility may need to principally target aortic stiffness and pulse pressure to have the potential to prevent cerebral small vessel disease.
Topics: Animals; Blood Pressure; Geese; Humans; Middle Aged; Middle Cerebral Artery; Pulse Wave Analysis; Vascular Stiffness
PubMed: 34852644
DOI: 10.1161/STROKEAHA.121.035560 -
Canadian Journal of Anaesthesia =... Apr 2023There is lack of consensus regarding the minimum arterial pulse pressure required for confirming permanent cessation of circulation for death determination by... (Review)
Review
PURPOSE
There is lack of consensus regarding the minimum arterial pulse pressure required for confirming permanent cessation of circulation for death determination by circulatory criteria in organ donors. We assessed direct and indirect evidence supporting whether one should use an arterial pulse pressure of 0 mm Hg vs more than 0 (5, 10, 20, 40) mm Hg to confirm permanent cessation of circulation.
SOURCE
We conducted this systematic review as part of a larger project to develop a clinical practice guideline for death determination by circulatory or neurologic criteria. We systematically searched Ovid MEDLINE, Ovid Embase, Cochrane Central Register of Controlled Trials (CENTRAL) via the Cochrane Library, and Web of Science for articles published from inception until August 2021. We included all types of peer-reviewed original research publications related to arterial pulse pressure as monitored by an indwelling arterial pressure transducer around circulatory arrest or determination of death with either direct context-specific (organ donation) or indirect (outside of organ donation context) data.
PRINCIPAL FINDINGS
A total of 3,289 abstracts were identified and screened for eligibility. Fourteen studies were included; three from personal libraries. Five studies were of sufficient quality for inclusion in the evidence profile for the clinical practice guideline. One study measured cessation of cortical scalp electroencephalogram (EEG) activity after withdrawal of life-sustaining measures and showed that EEG activity fell below 2 μV when the pulse pressure reached 8 mm Hg. This indirect evidence suggests there is a possibility of persistent cerebral activity at arterial pulse pressures > 5 mm Hg.
CONCLUSION
Indirect evidence suggests that clinicians may incorrectly diagnose death by circulatory criteria if they apply any arterial pulse pressure threshold of greater than 5 mm Hg. Moreover, there is insufficient evidence to determine that any pulse pressure threshold greater than 0 and less than 5 can safely determine circulatory death.
STUDY REGISTRATION
PROSPERO (CRD42021275763); first submitted 28 August 2021.
Topics: Humans; Blood Pressure; Brain; Tissue and Organ Procurement; Tissue Donors; Heart Arrest; Death
PubMed: 37138154
DOI: 10.1007/s12630-023-02425-2 -
Journal of Clinical Hypertension... Sep 2014This study aimed to quantitatively evaluate the predictive value of brachial pulse pressure and cardiovascular or all-cause mortality in the general population based on... (Meta-Analysis)
Meta-Analysis Review
This study aimed to quantitatively evaluate the predictive value of brachial pulse pressure and cardiovascular or all-cause mortality in the general population based on prospective observational studies by conducting a meta-analysis. Only prospective observational studies investigating baseline brachial pulse pressure and cardiovascular or all-cause mortality risk were selected from PubMed and Embase databases until July 2013. Fourteen studies involving 510,456 participants were analyzed. Pooled risk ratio (RR) of cardiovascular and all-cause mortality for the highest vs lowest brachial pulse pressure category was 1.80 (95% confidence interval [CI], 1.49-2.17) and 1.32 (95% CI, 1.23-1.41), respectively. Pooled RR of cardiovascular and all-cause mortality per 10 mm Hg pulse pressure increment was 1.13 (95% CI, 1.10-1.17) and 1.09 (95% CI, 1.07-1.11), respectively. Wide brachial pulse pressure is associated with greater risk of cardiovascular and all-cause mortality. However, more well-designed studies specifically on age and sex are needed to further confirm these findings.
Topics: Adult; Age Factors; Aged; Aged, 80 and over; Blood Pressure; Brachial Artery; Cardiovascular Diseases; Female; Humans; Hypertension; Male; Middle Aged; Observational Studies as Topic; Predictive Value of Tests; Prospective Studies; Risk Factors; Sex Factors
PubMed: 25052820
DOI: 10.1111/jch.12375