scholarly journals A Novel MRA-Based Framework for Segmenting the Cerebrovascular System and Correlating Cerebral Vascular Changes to Mean Arterial Pressure

2021 ◽  
Vol 11 (9) ◽  
pp. 4022
Author(s):  
Fatma Taher ◽  
Heba Kandil ◽  
Yitzhak Gebru ◽  
Ali Mahmoud ◽  
Ahmed Shalaby ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Mean Arterial Pressure ◽  
Arterial Pressure ◽  
Surrounding Tissue ◽  
Final Visit ◽  
P Value ◽  
Cerebral Vasculature ◽  
Tree Model ◽  
Non Invasive ◽  
Cerebrovascular System

Blood pressure (BP) changes with age are widespread, and systemic high blood pressure (HBP) is a serious factor in developing strokes and cognitive impairment. A non-invasive methodology to detect changes in human brain’s vasculature using Magnetic Resonance Angiography (MRA) data and correlation of cerebrovascular changes to mean arterial pressure (MAP) is presented. MRA data and systemic blood pressure measurements were gathered from patients (n = 15, M = 8, F = 7, Age = 49.2 ± 7.3 years) over 700 days (an initial visit and then a follow-up period of 2 years with a final visit.). A novel segmentation algorithm was developed to delineate brain blood vessels from surrounding tissue. Vascular probability distribution function (PDF) was calculated from segmentation data to correlate the temporal changes in cerebral vasculature to MAP calculated from systemic BP measurements. A 3D reconstruction of the cerebral vasculature was performed using a growing tree model. Segmentation results recorded 99.9% specificity and 99.7% sensitivity in identifying and delineating the brain’s vascular tree. The PDFs had a statistically significant correlation to MAP changes below the circle of Willis (p-value = 0.0007). This non-invasive methodology could be used to detect alterations in the cerebrovascular system by analyzing MRA images, which would assist clinicians in optimizing medical treatment plans of HBP.

Abstract 513: Impaired Hemodynamic Response to Head up Tilt in Adolescents Presenting with Chronic Nausea and Orthostatic Intolerance

Hypertension ◽  
2014 ◽  
Vol 64 (suppl_1) ◽  
Author(s):  
Hossam A Shaltout ◽  
Ashley L Wagoner ◽  
John E Fortunato ◽  
Debra I Diz
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Mean Arterial Pressure ◽  
Arterial Pressure ◽  
Orthostatic Intolerance ◽  
Frequency Method ◽  
Non Invasive ◽  
Head Up Tilt ◽  
Blood Pressures ◽  
Chronic Nausea

We previously reported that ~70% of adolescents presenting to a Pediatric GI clinic for chronic nausea exhibit orthostatic intolerance (OI) in response to head upright tilt testing (HUT). The objective of this study was to determine whether supine mean arterial pressure or hemodynamic responses to HUT differ in these patients. Forty-eight patients (mean age of 15 [10-18] years, 36 females) completed a 45 minutes 0 to 70° HUT. Continuous blood pressure and heart rate recordings were acquired using non-invasive finger cuff. Thirteen subjects had normal tilt (Normal) while thirty five demonstrated OI. There were no differences between the two groups in supine blood pressures (BP), baroreflex sensitivity measured by frequency method in HF range (BRS), heart rate variability (HRV) measured as the root of mean square of successive differences (rMSSD), blood pressure variability (BPV) measured as standard deviation of mean arterial pressure (SDMAP) or the sympathovagal balance measure LF RRI /HF RRI . HUT caused a greater increase in heart rate in OI group (from 71 ± 6 beats/min to 104 ± 4 in OI vs from 75 ± 3 to 95 ±3 in normal, p=0.01) which was accompanied with lesser increase in BP (mainly due to lack of increase in diastolic) in the OI group. There was a trend for greater reduction in BRS in OI subjects (from 28.5 ± 13 ms/mm Hg to 6.3 ± 0.8 in OI vs from 21.1 ± 3.6 to 12.0 ± 2.9 in normal, p=0.09). HUT impaired HRV in both groups compared to supine values but the reduction was greater in OI group (-66.7 ± 4 % vs -52.0 ±5.6 in normal, p=<0.001). SDMAP increased by HUT compared to supine but to a greater extent in OI (40.6 ± 4 % vs 13.4 ± 8 in normal, p=0.02). LF RRI /HF RRI increased to a greater magnitude in OI group with HUT (from 1.8 ± 0.8 to 6.8 ± 0.8 in OI vs from 1.14 ± 0.18 to 4.1 ±0.7 in normal, p=0.02). These data reveal that the adolescents with orthostatic intolerance have attenuated parasympathetic responses and exaggerated activation of the sympathetic system to the heart and blood vessels. Despite these responses, subjects fail to maintain BP. Similar to previous studies in other subjects with OI, the excessive tachycardia often followed by syncope in most of these adolescents may reflect a loss of vascular responses to the activation of sympathetic and neurohumoral stimuli. Support: AHA12CRP9420029

Abstract NS 4: Non-Invasive Oscillometric Blood Pressure Monitoring in tPA Treated Patients: Is Mean Arterial Pressure Associated with Patient Outcomes?

Stroke ◽  
2012 ◽  
Vol 43 (suppl_1) ◽  
Author(s):  
Anne W Alexandrov ◽  
Asad A Chaudhary ◽  
April Sisson ◽  
Kara Sands ◽  
Pawan Rawal ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Mean Arterial Pressure ◽  
Arterial Pressure ◽  
Intracerebral Hemorrhage ◽  
Acute Stroke ◽  
National Standard ◽  
Stroke Patients ◽  
Non Invasive ◽  
Symptomatic Intracerebral Hemorrhage ◽  
Stroke Center

Background: Blood pressure (BP) parameters for management of tPA treated patients are well known among experienced stroke clinicians, and violation of systolic and diastolic BP limits have previously been shown to be associated with symptomatic intracerebral hemorrhage (sICH) in tPA treated patients. Non-invasive oscillometric BP monitoring measures a “true” mean arterial pressure (MAP), and then algorithmically defines what systolic and diastolic pressure "might" be. Because this form of BP monitoring has become the national standard, we examined the occurrence of MAP BP elevations to determine their association with sICH and treatment outcome in acute ischemic stroke patients that received systemic tPA. Methods: Two-years of consecutive systemic tPA cases were retrieved from our Stroke Center database and arterial blood pressures for the first 24 hours from time of bolus were entered from auto-recordings in our electronic medical records. Protocol violations in MAP were defined as greater than 120 mm Hg at any point in the first 24 hours from time of bolus. Off-label treatment with intravenous tPA beyond 4.5 hours from symptom onset was identified a priori as a potential counfounder to stroke outcome. Symptomatic intracerebral hemorrhage was defined as an increase in the NIHSS of ≥ 4 points. Spearman’s correlation was used to assess the relationship between MAP and post-tPA NIHSS score. Results: 191 tPA cases were identified for inclusion in the analysis with 150 (79%) receiving their tPA at our Comprehensive Stroke Center and another 41 (21%) administered as a telephone-consult supported drip and ship. Patients were 65.5±16 years of age with median admission NIHSS scores of 12 (IQR=7-17). All patients had normal CT scans or minor changes consistent with acute stroke without hypo-attenuation. A total of 77 (40%) patients experienced a MAP violation overall. There were 11 isolated systolic BP violations, 4 isolated diastolic BP violations, and 21 isolated MAP violations that were otherwise not detectable by a violation in systolic or diastolic parameters, averaging 123.3±2 mm Hg. A total of 2 (1%) sICHs occurred in the sample, and of these 1 was associated with on-label peri-treatment BP protocol violations affecting systolic, diastolic and MAP parameters. An increased reduction in post-tPA NIHSS points was significantly associated with higher MAPs (r=.92; p=.008). Conclusions: Evidence-based guidelines are silent on MAP limits, and MAP is rarely monitored clinically in tPA treated patients despite dependence on the MAP for assignment of systolic and diastolic pressures in oscillometric BP monitoring. Our findings suggest that an improved understanding of the contribution of MAP-dependent oscillometric methods to BP monitoring in acute stroke patients is warranted.

scholarly journals Measurement of mean arterial pressure: comparison of the Vasotrac monitor with the finger differential oscillometric device

2010 ◽  
pp. 691-696 ◽  
Author(s):  
K Jagomägi ◽  
R Raamat ◽  
J Talts ◽  
U Ragun ◽  
P Tähepõld
Keyword(s):  
Blood Pressure ◽  
Mean Arterial Pressure ◽  
Arterial Pressure ◽  
Radial Artery ◽  
Blood Pressure Monitoring ◽  
Signal Conditioning ◽  
Non Invasive ◽  
Arterial Blood ◽  
Oscillometric Device ◽  
Good Agreement

The Vasotrac monitor provides non-invasive near-continuous blood pressure monitoring and is designed to be an alternative to direct intra-arterial blood pressure (BP) measurement. As compared to radial artery invasive BP and upper arm noninvasive BP, Vasotrac readings have been found to have a good agreement with them. However, discrepancies have been reported when rapid changes in BP exist. In the present study we compared BP measured by the Vasotrac monitor on the radial artery with that recorded on the finger arteries by the differential oscillometric device allowing measurement on the beat-to-beat basis. Comparisons were performed on the mean arterial pressure (MAP) level. Special attention was paid to the signal conditioning before comparison of pressures of different temporal resolution. Altogether 383 paired MAP measurements were made in 14 healthy subjects. Based on all 383 paired measurements, the MAP values measured at the radial artery at rest were 4.8±6.0 mm Hg higher than those measured on fingers. The observed difference between the Vasotrac and differential oscillometric device can be explained by different measurement sites. This result is consistent with previous investigations, and the Vasotrac monitor can be considered to adequately track relatively rapid MAP changes on the radial artery. Attention should be paid to a proper signal conditioning before comparison of results obtained by different devices.

CHARACTERISTICS OF 24-HOUR BLOOD PRESSURE INDICATORS IN PATIENTS WITH HYPERTENSION AND CHRONIC OBSTRUCTIVE PULMONARY DISEASE

2020 ◽  
pp. 31-41
Author(s):  
M.A. Bubnova ◽  
O.N. Kryuchkova
Keyword(s):  
Blood Pressure ◽  
Chronic Obstructive Pulmonary Disease ◽  
Mean Arterial Pressure ◽  
High Risk ◽  
Arterial Pressure ◽  
Pulmonary Disease ◽  
Comparison Group ◽  
Cardiovascular Complications ◽  
Chronic Obstructive ◽  
Obstructive Pulmonary Disease

Patients with hypertension (HT) and chronic obstructive pulmonary disease (COPD) have a high risk of cardiovascular complications. Up to now, there is no optimal strategy for combined antihypertensive therapy. Still, the data of 24-hour blood pressure monitoring (BPM) are important while choosing treatment tactics. The aim of the paper is to study the features of indicators in patients with arterial hypertension (AH) and COPD. Materials and methods. 130 patients with HT were included in the study. The main group (n=90) included comorbid patients with HT and COPD, their average age was 61.30±1.01; the comparison group (n=40) consisted of patients with HT, their average age was 59.10±1.53. All patients underwent 24-hour BPM. Results. Comorbid patients revealed an increase in the mean 24-hour and night systolic and mean arterial pressure values as well as a significant increase in the load index of systolic, diastolic and mean arterial pressure. Also, comorbid patients demonstrated higher blood pressure in contrast to the patients of the comparison group. They had increased systolic, diastolic and mean blood pressure variability and a quicker rate of morning blood pressure rise. According to 24-hour blood pressure dynamics, pathological types of the 24-hour blood pressure curve, a higher frequency of the night-peaker profile dominated in patients with COPD if compared to patients with HT. Conclusion. The obtained data indicated a high risk of cardiovascular complications in comorbid patients, early target organ damage and an unfavorable disease prognosis. It means that both further study of hypertension clinical course in such patients and personalization of antihypertensive therapy are relevant. Keywords: hypertension, chronic obstructive pulmonary disease, 24-hour monitoring, blood pressure. Пациенты с артериальной гипертензией (АГ) и хронической обструктивной болезнью легких (ХОБЛ) имеют высокий риск возникновения кардиоваскулярных осложнений. В настоящее время в лечении не определена наиболее оптимальная стратегия комбинированной антигипертензивной терапии. Для выбора тактики терапии важную роль играют показатели суточного мониторирования артериального давления (СМАД). Цель. Изучить особенности показателей СМАД у пациентов с АГ на фоне ХОБЛ. Материалы и методы. В исследование включено 130 пациентов с АГ. В основную группу (n=90) вошли пациенты с АГ и ХОБЛ (средний возраст – 61,30±1,01 года), в группу сравнения (n=40) – больные только АГ (средний возраст – 59,10±1,53 года). Всем пациентам проведено СМАД. Результаты. У пациентов с коморбидностью выявлены следующие особенности суточных показателей артериального давления: увеличение значений среднесуточных и средненочных показателей систолического и среднего артериального давления; существенное повышение индекса нагрузки систолическим, диастолическим и средним артериальным давлением. Также эти больные отличались от пациентов группы сравнения более высокими значениями пульсового давления, имели повышенную вариабельность систолического, диастолического и среднего артериального давления, у них наблюдалось увеличение скорости утреннего подъема артериального давления. Суточная динамика артериального давления у пациентов с ХОБЛ характеризовалась преобладанием патологических типов суточной кривой АД, более высокой частотой профиля night-peaker по сравнению с больными только АГ. Выводы. Выявленные особенности свидетельствуют о высоком риске сердечно-сосудистых осложнений у пациентов с коморбидностью, раннем поражении органов-мишеней и неблагоприятном прогнозе заболевания, что требует дальнейшего изучения особенностей клинического течения АГ у таких больных и индивидуализации антигипертензивной терапии. Ключевые слова: артериальная гипертензия, хроническая обструктивная болезнь легких, суточное мониторирование, артериальное давление.

scholarly journals Plasticity in breathing and arterial blood pressure following acute intermittent hypercapnic hypoxia in infant rat pups with a partial loss of 5-HT neurons

2015 ◽  
Vol 309 (10) ◽  
pp. R1273-R1284 ◽  
Author(s):  
Jennifer Magnusson ◽  
Kevin J. Cummings
Keyword(s):  
Blood Pressure ◽  
Mean Arterial Pressure ◽  
Arterial Pressure ◽  
Arterial Blood Pressure ◽  
Cardiovascular Responses ◽  
Partial Loss ◽  
Rat Pups ◽  
Arterial Blood ◽  
Hypercapnic Hypoxia ◽  
Long Term Facilitation

The role of serotonin (5-HT) neurons in cardiovascular responses to acute intermittent hypoxia (AIH) has not been studied in the neonatal period. We hypothesized that a partial loss of 5-HT neurons would reduce arterial blood pressure (BP) at rest, increase the fall in BP during hypoxia, and reduce the long-term facilitation of breathing (vLTF) and BP following AIH. We exposed 2-wk-old, 5,7-dihydroxytryptamine-treated and controls to AIH (10% O2; n = 13 control, 14 treated), acute intermittent hypercapnia (5% CO2; n = 12 and 11), or acute intermittent hypercapnic hypoxia (AIHH; 10% O2, 5% CO2; n = 15 and 17). We gave five 5-min challenges of AIH and acute intermittent hypercapnia, and twenty ∼20-s challenges of AIHH to mimic sleep apnea. Systolic BP (sBP), diastolic BP, mean arterial pressure, heart rate (HR), ventilation (V̇e), and metabolic rate (V̇o2) were continuously monitored. 5,7-Dihydroxytryptamine induced an ∼35% loss of 5-HT neurons from the medullary raphe. Compared with controls, pups deficient in 5-HT neurons had reduced resting sBP (∼6 mmHg), mean arterial pressure (∼5 mmHg), and HR (56 beats/min), and experienced a reduced drop in BP during hypoxia. AIHH induced vLTF in both groups, reflected in increased V̇e and V̇e/V̇o2, and decreased arterial Pco2. The sBP of pups deficient in 5-HT neurons, but not controls, was increased 1 h following AIHH. Our data suggest that a relatively small loss of 5-HT neurons compromises resting BP and HR, but has no influence on ventilatory plasticity induced by AIHH. AIHH may be useful for reversing cardiorespiratory defects related to partial 5-HT system dysfunction.

Hypotensive and Regional Haemodynamic Effects of Exercise, Fasted and after Food, in Human Sympathetic Denervation

1998 ◽  
Vol 94 (1) ◽  
pp. 49-55 ◽  
Author(s):  
Sharmini Puvi-Rajasingham ◽  
Gareth D. P. Smith ◽  
Adeola Akinola ◽  
Christopher J. Mathias
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Mean Arterial Pressure ◽  
Arterial Pressure ◽  
Superior Mesenteric Artery ◽  
Vascular Resistance ◽  
Mesenteric Artery ◽  
Autonomic Failure ◽  
Sympathetic Denervation ◽  
Stroke Distance

1. In human sympathetic denervation due to primary autonomic failure, food and exercise in combination may produce a cumulative blood pressure lowering effect due to simultaneous splanchnic and skeletal muscle dilatation unopposed by corrective cardiovascular reflexes. We studied 12 patients with autonomic failure during and after 9 min of supine exercise, when fasted and after a liquid meal. Standing blood pressure was also measured before and after exercise. 2. When fasted, blood pressure fell during exercise from 162 ± 7/92 ± 4 to 129 ± 9/70 ± 5 mmHg (mean arterial pressure by 22 ± 5%), P < 0.0005. After the meal, blood pressure fell from 159 ± 8/88 ± 6 to 129 ± 6/70 ± 4 mmHg (mean arterial pressure by 22 ± 3%), P < 0.0001, and further during exercise to 123 ± 6/61 ± 3 mmHg (mean arterial pressure by 9 ± 3%), P < 0.01. The stroke distance—heart rate product, an index of cardiac output, did not change after the meal. During exercise, changes in the stroke distance—heart rate product were greater when fasted. 3. Resting forearm and calf vascular resistance were higher when fasted. Calf vascular resistance fell further after exercise when fasted. Resting superior mesenteric artery vascular resistance was lower when fed; 0.19 ± 0.02 compared with 032 ± 0.06, P < 0.05. After exercise, superior mesenteric artery vascular resistance had risen by 82%, to 0.53 ± 0.12, P < 0.05 (fasted) and by 47%, to 0.29 ± 0.05, P < 0.05 (fed). 4. On standing, absolute levels of blood pressure were higher when fasted [83 ± 7/52 ± 7 compared with 71 ± 2/41 ± 3 (fed), each P < 0.05]. Subjects were more symptomatic on standing post-exercise when fed. 5. In human sympathetic denervation, exercise in the fed state lowered blood pressure further than when fasted and worsened symptoms of postural hypotension.

Increased vascular resistance in paralyzed legs after spinal cord injury is reversible by training

2002 ◽  
Vol 93 (6) ◽  
pp. 1966-1972 ◽  
Author(s):  
Maria T. E. Hopman ◽  
Jan T. Groothuis ◽  
Marcel Flendrie ◽  
Karin H. L. Gerrits ◽  
Sibrand Houtman
Keyword(s):  
Blood Pressure ◽  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Blood Flow ◽  
Mean Arterial Pressure ◽  
Arterial Pressure ◽  
Vascular Resistance ◽  
Arterial Blood Flow ◽  
Arterial Blood ◽  
Cord Injury

The purpose of the present study was to determine the effect of a spinal cord injury (SCI) on resting vascular resistance in paralyzed legs in humans. To accomplish this goal, we measured blood pressure and resting flow above and below the lesion (by using venous occlusion plethysmography) in 11 patients with SCI and in 10 healthy controls (C). Relative vascular resistance was calculated as mean arterial pressure in millimeters of mercury divided by the arterial blood flow in milliliters per minute per 100 milliliters of tissue. Arterial blood flow in the sympathetically deprived and paralyzed legs of SCI was significantly lower than leg blood flow in C. Because mean arterial pressure showed no differences between both groups, leg vascular resistance in SCI was significantly higher than in C. Within the SCI group, arterial blood flow was significantly higher and vascular resistance significantly lower in the arms than in the legs. To distinguish between the effect of loss of central neural control vs. deconditioning, a group of nine SCI patients was trained for 6 wk and showed a 30% increase in leg blood flow with unchanged blood pressure levels, indicating a marked reduction in vascular resistance. In conclusion, vascular resistance is increased in the paralyzed legs of individuals with SCI and is reversible by training.

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