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Erkoç Ataoğlu E, Batur Çağlayan H, Nazliel B, Çinar M, Akyol Gürses A, Moraloğlu Tekin Ö. Middle Cerebral Artery Blood Flow Velocity During Normal Pregnancy. Neurologist 2024; 29:45-49. [PMID: 37607532 DOI: 10.1097/nrl.0000000000000523] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/24/2023]
Abstract
BACKGROUND The present study aimed to evaluate resting middle cerebral artery (MCA) blood flow velocities using transcranial Doppler ultrasound (TCD) in healthy women at different stages of pregnancy, and to compare these velocities with those of normal controls. METHODS A total of 105 healthy normotensive pregnant women and 25 non-pregnant healthy controls were included in the study. We formed 3 groups according to gestational age: first trimester (7 to 13 wk pregnant), second trimester (14 to 28 wk pregnant), and third trimester (29 to 42 wk pregnant). Age, body mass index, heart rate, arterial blood pressure, and hematological data were recorded and TCD was performed on the subjects. Regarding TCD, we evaluated the mean cerebral blood flow velocity, the peak systolic velocity, the end-diastolic flow velocity, S/D ratio, the pulsatility Index (PI) and the resistance Index (RI). RESULTS The MCA mean blood flow velocities differed significantly among the groups ( P <0.001) and were higher in the controls than those of the first trimester, second trimester, and third trimester groups ( P <0.01, P <0.001, P <0.001 respectively). The MCA mean and peak blood flow velocities, and the PI and RI decreased significantly with advancing gestation. CONCLUSIONS TCD is a noninvasive and non-toxic method of monitoring the adaptation of the maternal cerebral blood flow in pregnancy. The progressive decreases in the MCA mean and peak blood flow velocities, PI, and RI during gestation may be the result of chemical and neuronal factors. This study supports the need for additional studies using TCD to establish normative cerebral blood flow volumes throughout pregnancy.
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Affiliation(s)
| | | | - Bijen Nazliel
- Department of Neurology, Faculty of Medicine, Gazi University
| | - Mehmet Çinar
- Department of Obstetrics and Gynecology, University of Health Sciences, Ankara, Turkey
| | | | - Özlem Moraloğlu Tekin
- Department of Obstetrics and Gynecology, University of Health Sciences, Ankara, Turkey
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Brislane Á, Steinback CD, Davenport MH. The Nine Month Stress Test: Pregnancy and Exercise - Similarities and Interactions. Can J Cardiol 2021; 37:2014-2025. [PMID: 34534622 DOI: 10.1016/j.cjca.2021.09.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2021] [Revised: 08/18/2021] [Accepted: 09/03/2021] [Indexed: 11/29/2022] Open
Abstract
Of all physiological systems, the cardiovascular system takes on the most profound adaptation in pregnancy to support fetal growth and development. The adaptations that arise are systemic and involve structural and functional changes that can be observed at the cerebral, central, peripheral, and microvascular beds. This includes, although is not limited to increased heart rate, stroke volume and cardiac output with negligible change to blood pressure, reductions in vascular resistance and cerebral blood flow velocity, systemic artery enlargement, enhanced endothelial function. All of this takes place to accommodate blood volume expansion and ensure adequate fetal and maternal oxygen delivery. In some instances, the demand placed on the vasculature can manifest as cardiovascular maladaptation and thus, cardiovascular complications can arise. Exercise is recommended in pregnancy because of its powerful ability to reduce the incidence and severity of cardiovascular complications in pregnancy. However, the mechanism by which it acts is poorly understood. The first aim of this review is to describe the systemic adaptations that take place in pregnancy. Secondly, this review aims to describe the influence of exercise on these systemic adaptations. It is anticipated that this review can comprehensively capture the extent of knowledge in this area while identifying areas that warrant further investigation.
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Affiliation(s)
- Áine Brislane
- Program for Pregnancy & Postpartum Health, Neurovascular Health Lab, Faculty of Kinesiology, Sport, and Recreation, Women and Children's Health Research Institute, Alberta Diabetes Institute, University of Alberta, Alberta, Canada
| | - Craig D Steinback
- Program for Pregnancy & Postpartum Health, Neurovascular Health Lab, Faculty of Kinesiology, Sport, and Recreation, Women and Children's Health Research Institute, Alberta Diabetes Institute, University of Alberta, Alberta, Canada
| | - Margie H Davenport
- Program for Pregnancy & Postpartum Health, Neurovascular Health Lab, Faculty of Kinesiology, Sport, and Recreation, Women and Children's Health Research Institute, Alberta Diabetes Institute, University of Alberta, Alberta, Canada.
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3
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Physiology of the cerebrovascular adaptation to pregnancy. HANDBOOK OF CLINICAL NEUROLOGY 2021. [PMID: 32736760 DOI: 10.1016/b978-0-444-64239-4.00004-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/30/2023]
Abstract
The adaptation of the cerebral circulation to pregnancy is unique compared with other organs and circulatory systems, because the brain requires relatively constant blood flow and water and solute composition to maintain homeostasis. Thus, a major adaptation of the maternal cerebrovasculature to pregnancy is to maintain normalcy in the face of expanded plasma volume, increased cardiac output, and high levels of permeability factors. In this chapter, the effect of pregnancy on critical functions of the cerebral circulation is discussed, including changes occurring at the endothelium and blood-brain barrier (BBB), which protect the maternal brain from changes in BBB permeability. Further, pregnancy-induced changes in the structure and function of cerebral arteries, arterioles, and veins will be discussed as they relate to cerebral vascular resistance, hemodynamics, and cerebral blood flow autoregulation.
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Skinner BD, Davies RJ, Weaver SR, Cable NT, Lucas SJE, Lucas RAI. A Systematic Review and Meta-Analysis Examining Whether Changing Ovarian Sex Steroid Hormone Levels Influence Cerebrovascular Function. Front Physiol 2021; 12:687591. [PMID: 34220552 PMCID: PMC8248489 DOI: 10.3389/fphys.2021.687591] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Accepted: 05/21/2021] [Indexed: 01/14/2023] Open
Abstract
Sex differences in cerebrovascular disease rates indicate a possible role for ovarian sex steroid hormones in cerebrovascular function. To synthesise and identify knowledge gaps, a systematic review and meta-analysis was conducted to assess how ovarian sex steroid hormone changes across the lifespan affect cerebrovascular function in women. Three databases (EMBASE, MEDLINE and Web of Science) were systematically searched for studies on adult cerebrovascular function and ovarian sex steroid hormones. Forty-five studies met pre-defined inclusion criteria. Studied hormone groups included hormone replacement therapy (HRT; n = 17), pregnancy (n = 12), menstrual cycle (n = 7), menopause (n = 5), oral contraception (n = 2), and ovarian hyperstimulation (n = 2). Outcome measures included pulsatility index (PI), cerebral blood flow/velocity (CBF), resistance index (RI), cerebral autoregulation, and cerebrovascular reactivity. Meta-analysis was carried out on HRT studies. PI significantly decreased [−0.05, 95% CI: (−0.10, −0.01); p = 0.01] in post-menopausal women undergoing HRT compared to post-menopausal women who were not, though there was considerable heterogeneity (I2 = 96.8%). No effects of HRT were seen in CBF (p = 0.24) or RI (p = 0.77). This review indicates that HRT improves PI in post-menopausal women. However, there remains insufficient evidence to determine how changing ovarian sex steroid hormone levels affects cerebrovascular function in women during other hormonal phases (e.g., pregnancy, oral contraception).
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Affiliation(s)
- Bethany D Skinner
- School of Sport, Exercise and Rehabilitation Sciences, College of Life and Environmental Sciences, University of Birmingham, Birmingham, United Kingdom.,Centre for Human Brain Health, University of Birmingham, Birmingham, United Kingdom
| | - Rebecca J Davies
- School of Sport, Exercise and Rehabilitation Sciences, College of Life and Environmental Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Samuel R Weaver
- School of Sport, Exercise and Rehabilitation Sciences, College of Life and Environmental Sciences, University of Birmingham, Birmingham, United Kingdom.,Centre for Human Brain Health, University of Birmingham, Birmingham, United Kingdom
| | - N Tim Cable
- School of Sport, Exercise and Rehabilitation Sciences, College of Life and Environmental Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Samuel J E Lucas
- School of Sport, Exercise and Rehabilitation Sciences, College of Life and Environmental Sciences, University of Birmingham, Birmingham, United Kingdom.,Centre for Human Brain Health, University of Birmingham, Birmingham, United Kingdom
| | - Rebekah A I Lucas
- School of Sport, Exercise and Rehabilitation Sciences, College of Life and Environmental Sciences, University of Birmingham, Birmingham, United Kingdom
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Effectiveness of nebulized dexmedetomidine for treatment of post-dural puncture headache in parturients undergoing elective cesarean section under spinal anesthesia: a randomized controlled study. J Anesth 2021; 35:515-524. [PMID: 33993346 DOI: 10.1007/s00540-021-02944-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Accepted: 05/03/2021] [Indexed: 10/21/2022]
Abstract
PURPOSE The need for effective treatment for post-dural puncture headache (PDPH) is a growing research entity. This study aimed to test the effectiveness of additional dexmedetomidine (DEX) to PDPH conservative management and evaluate its cerebral hemodynamic effects trans-cranial Doppler. METHODS This prospective randomized double-blind controlled trial was conducted on 43 post-partum females suffering from PDPH with visual analog score (VAS) ≥ 4 and Lybecker score ≥ 2. The study subjects were allocated into control group [n = 22] received nebulization of 4 mL 0.9% saline and DEX group [n = 21] received nebulization of 1 µg/kg DEX diluted in 4 mL 0.9% saline twice daily that was continued until achieving VAS score ≤ 3 and Lybecker score < 2 and/or for a maximum of 72 h. Both groups received routine conservative management. The primary outcome was the VAS and Lybecker scores and the secondary results were the DEX effects on cerebral vessels and the occurrence of any adverse effects. RESULTS VAS and Lybecker scores were significantly lower in DEX group. The middle cerebral artery mean flow velocity was significantly lower, and the pulsatility index was considerably higher after DEX nebulization compared to placebo. Two patients in the control group were indicated for epidural blood patch. CONCLUSION The addition of DEX nebulization (1 µg/kg twice daily) to the PDPH conservative care effectively relieved the symptoms and lowered pain scores which could be due to its analgesic and cerebral vasoconstrictive effects. TRIAL REGISTRATION This study was approved by the research ethical committee of Faculty of Medicine, Zagazig University with the reference number (ZU-IRB#: 6075/26-4-2020) and it was registered under clinicaltrials.gov (NCT04327726).
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Maternal microvascular dysfunction during preeclamptic pregnancy. Clin Sci (Lond) 2021; 135:1083-1101. [PMID: 33960392 DOI: 10.1042/cs20200894] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2020] [Revised: 04/19/2021] [Accepted: 04/21/2021] [Indexed: 12/15/2022]
Abstract
Preeclampsia is a hypertensive disorder of pregnancy effecting ∼5-8% of pregnancies in the United States, and ∼8 million pregnancies worldwide. Preeclampsia is clinically diagnosed after the 20th week of gestation and is characterized by new onset hypertension accompanied by proteinuria and/or thrombocytopenia, renal insufficiency, impaired liver function, pulmonary edema, or cerebral or visual symptoms. This broad definition emphasizes the heterogeneity of the clinical presentation of preeclampsia, but also underscores the role of the microvascular beds, specifically the renal, cerebral, and hepatic circulations, in the pathophysiology of the disease. While the diagnostic criteria for preeclampsia relies on the development of de novo hypertension and accompanying clinical symptoms after 20-week gestation, it is likely that subclinical dysfunction of the maternal microvascular beds occurs in parallel and may even precede the development of overt cardiovascular symptoms in these women. However, little is known about the physiology of the non-reproductive maternal microvascular beds during preeclampsia, and the mechanism(s) mediating microvascular dysfunction during preeclamptic pregnancy are largely unexplored in humans despite their integral role in the pathophysiology of the disease. Therefore, the purpose of this review is to provide a summary of the existing literature on maternal microvascular dysfunction during preeclamptic pregnancy by reviewing the functional evidence in humans, highlighting potential mechanisms, and providing recommendations for future work in this area.
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Saikia P. Predictive performance of transcranial Doppler for PDPH. J Anesth 2019; 34:158. [PMID: 31482375 DOI: 10.1007/s00540-019-02677-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2019] [Accepted: 08/24/2019] [Indexed: 11/24/2022]
Affiliation(s)
- Priyam Saikia
- Department of Anaesthesiology and Critical Care, Gauhati Medical College and Hospital, Guwahati, Assam, 781032, India.
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Transcranial Doppler role in prediction of post-dural puncture headache in parturients undergoing elective cesarean section: prospective observational study. J Anesth 2019; 33:426-434. [PMID: 31073654 DOI: 10.1007/s00540-019-02652-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2019] [Accepted: 05/02/2019] [Indexed: 11/27/2022]
Abstract
PURPOSE Post-dural puncture headache (PDPH) may be resulted from significant changes in cerebral blood flow, which could be visualized by Transcranial Doppler (TCD). This study was performed to investigate if TCD can be used to predict the occurrence of PDPH in high-risk patients. METHODS This prospective observational study was conducted on ninety ASA I and II pregnant females undergoing elective cesarean section (CS) under spinal anesthesia. TCD was performed to all patients within 24 h before the operation, at 24 h and 48 h in the post-operative period to measure mean velocity (MV) and Gosling pulsatility index (PI) in the right middle cerebral artery. For 5 days postoperatively, all patients were assessed and the PDPH patients were identified, their pre- and post-puncture TCD measurements were compared with the corresponding measurements of PDPH-free patients and ROC analysis was done to evaluate the predictive value of TCD parameters. RESULTS 17 patients (18.8%) developed PDPH. PDPH group was significantly higher regarding MV and significantly lower with regard to PI at all times except for the pre-spinal PI. The MV values in all patients showed statistical significant increase within the first 48 h after CS as compared with those before delivery. In PDPH group there was high statistical significant decrease in PI values at 24 h and 48 h compared to the pre-puncture values. The pre-puncture MV was the parameter of the best accuracy for predicting PDPH with a cutoff of MV > 68.4 cm/s and the post-puncture PI at 24 h was the best predictive of PDPH with a cutoff value of < 0.75. CONCLUSION TCD might prove a useful tool in predicting PDPH suggesting that higher pre-puncture MV with a cutoff value > 68.4 cm/s and post-puncture lower PI at 24 h with a cutoff < 0.75 are the best predictive parameters. TRIAL REGISTRATION This clinical trial was registered with ClinicalTrials.gov (NCT03464253).
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Ekşi MŞ, Öğrenci A, Batçık OE, Koban O. Management of Obstructive Hydrocephalus in Pregnant Patient. Asian J Neurosurg 2018; 13:123-127. [PMID: 29492141 PMCID: PMC5820866 DOI: 10.4103/1793-5482.181127] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
De novo obstructive hydrocephalus is a rare event during pregnancy. There are only case reports presented in literature. We aimed to discuss the pathophysiological basis and management options with an exemplary case presentation and review of the current literature. A 28-year-old G2P1 patient presented to our clinic with headache, vomiting, and deteriorated vision at the 8th week of gestation. She had no history of central nervous system infection or trauma. A brain magnetic resonance imaging was obtained. There was hydrocephalus due to cerebral aqueduct stenosis (Evan's index of 58%). She was managed conservatively with bed rest and diuretics; however, she got no relief. A ventriculoperitoneal shunt was inserted at the 13th week of gestation. At the 38th week, she had cesarean section (C/S) due to previous history of C/S in the first pregnancy and present cord entanglement of the fetus. C/S was conducted under epidural anesthesia after conforming she had no increased intra cranial pressure findings. Delivery was uneventful with a healthy newborn. Obstructive hydrocephalus is a very rare complication during pregnancy. Hydrocephalus becomes obvious and necessitates treatment, before the third trimester of pregnancy. Timely diagnosis, especially differentiation from preeclampsia, is a life-saving step. If no complication happens during intervention for hydrocephalus, spontaneous vaginal delivery is a safe way of delivery for both mother's and newborn's well-being. C/S should be saved for obstetrical indications and can be conducted under epidural anesthesia if intracranial pressure is kept under control. Interdisciplinary approach of neurosurgeons and anesthesiologists is pivotal for delicate care of the patient and the baby.
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Affiliation(s)
- Murat Şakir Ekşi
- Department of Orthopedic Surgery, University of California at San Francisco, San Francisco, CA, USA
| | - Ahmet Öğrenci
- Department of Neurosurgery, Batman State Hospital, Batman, Turkey
| | | | - Orkun Koban
- Department of Neurosurgery, Goztepe Medical Park, Istanbul, Turkey
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Anzola GP, Brighenti R, Cobelli M, Giossi A, Mazzucco S, Olivato S, Pari E, Piras MP, Padovani A, Rinaldi F, Turri G. Cerebral haemodynamics in early puerperium: A prospective study. ULTRASOUND (LEEDS, ENGLAND) 2017; 25:107-114. [PMID: 28567105 PMCID: PMC5438056 DOI: 10.1177/1742271x17690942] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2016] [Accepted: 01/08/2017] [Indexed: 11/15/2022]
Abstract
AIM Prospective study on 900 consecutive puerperae to assess normal values and range of the blood flow velocity in the middle cerebral artery in both hemispheres. MATERIAL AND METHOD M1 and M2 segments of both middle cerebral arteries were assessed in all subjects within 96 hours of delivery. Mean flow velocity was recorded after adjusting for insonation angle. Lindegaard index (LI = middle cerebral artery-Internal Carotid Artery mean flow velocity ratio) was calculated whenever the mean flow velocity exceeded 100 cm/second. Asymmetry indexes were calculated inter hemispherically for M1 and M2 segments separately. RESULTS Mean flow velocities were 74 ± 17 and 72 ± 17 in right and 73 ± 17 and 72 ± 17 cm/second in the left M1 and M2, respectively. A total of 136 subjects (12.1%) exceeded the threshold of 100 cm/second, but LI was consistently <3 in all of them. Mean flow velocity was inversely and independently correlated to haemoglobin levels and to parity. Mean asymmetry indexes were 0.25 ± 23 in M1 and 0.45 ± 25 in M2. CONCLUSION Mean flow velocity in the middle cerebral artery of healthy subjects in early puerperium is higher than in age-matched non-puerperal women and may exceed the threshold of 100 cm/second with no evidence of intracranial spasm, because of blood loss during delivery. Mean flow velocity is independently correlated with parity. Right-to-left mean flow velocity asymmetry may reach 50% as a consequence of a transient imbalance in vascular tone regulation.
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Affiliation(s)
- GP Anzola
- Consultant Neurologist, Villa Gemma Hospital, Gardone Riviera, Italy
| | - R Brighenti
- Department of Obstetrics and Gynaecology, Poliambulanza Hospital, Brescia, Italy
| | - M Cobelli
- Department of Radiology, Poliambulanza Hospital, Brescia, Italy
| | - A Giossi
- Department of Neurology, Azienda Socio Sanitaria Territoriale, Cremona, Italy
| | - S Mazzucco
- Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK
| | | | - E Pari
- Deparment of Neurology, Spedali Civili, University of Brescia, Brescia, Italy
| | - MP Piras
- Deparment of Neurology, Poliambulanza Hospital, Brescia, Italy
| | - A Padovani
- Deparment of Neurology, Spedali Civili, University of Brescia, Brescia, Italy
| | - F Rinaldi
- Deparment of Neurology, Spedali Civili, University of Brescia, Brescia, Italy
| | - G Turri
- Department of Neurosciences, Biomedicine and Movement Sciences, University Hospital of Verona, Verona, Italy
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Johnson AC, Cipolla MJ. The cerebral circulation during pregnancy: adapting to preserve normalcy. Physiology (Bethesda) 2015; 30:139-47. [PMID: 25729059 DOI: 10.1152/physiol.00048.2014] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
The adaptation of the brain and cerebral circulation to pregnancy are unique compared with other organs and circulatory systems, ultimately functioning to maintain brain homeostasis. In this review, the effect of pregnancy on critical functions of the cerebral circulation is discussed, including changes occurring at the endothelium and blood-brain barrier, and changes in the structure and function of cerebral arteries and arterioles, hemodynamics, and cerebral blood flow autoregulation.
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Affiliation(s)
- Abbie C Johnson
- Department of Neurological Sciences, University of Vermont College of Medicine, Burlington, Vermont
| | - Marilyn J Cipolla
- Department of Neurological Sciences, University of Vermont College of Medicine, Burlington, Vermont
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van Veen TR, Haeri S, Sangi-Haghpeykar H, Belfort MA. Changes in maternal posterior and anterior cerebral artery flow velocity during pregnancy and postpartum--a longitudinal study. JOURNAL OF CLINICAL ULTRASOUND : JCU 2013; 41:532-537. [PMID: 23996414 DOI: 10.1002/jcu.22091] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2012] [Revised: 06/04/2013] [Accepted: 07/17/2013] [Indexed: 06/02/2023]
Abstract
BACKGROUND To evaluate the normal range of blood flow velocity in the maternal anterior (ACA) and posterior cerebral arteries (PCA) along the normal pregnancy and postpartum period. METHODS Transcranial Doppler ultrasound was used to measure the systolic, diastolic, and mean blood velocities in the ACA and PCA during normal gestation. The resistance and pulsatility indices were calculated. Data were analyzed using multilevel modeling, incorporating random effects models, to construct mean and percentile curves. RESULTS We performed 355 measurements on 59 patients, which showed that systolic and mean velocity in the ACA decreased, whereas diastolic velocity increased in the PCA during normal pregnancy. Resistance and pulsatility indices in both vessels increased to a maximum in the second trimester, decreased during the third trimester, and increased during the postpartum period. CONCLUSIONS This study provides normative data for ACA and PCA velocity and indices during pregnancy and postpartum, demonstrating changes in velocity that suggest a shift of cerebral blood flow from the anterior to the posterior cerebral circulation.
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Affiliation(s)
- Teelkien R van Veen
- Department of Obstetrics and Gynecology, University Medical Center Groningen, Groningen, The Netherlands; Department of Obstetrics and Gynecology, Baylor College of Medicine, Houston, TX, USA
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Cipolla MJ. The adaptation of the cerebral circulation to pregnancy: mechanisms and consequences. J Cereb Blood Flow Metab 2013; 33:465-78. [PMID: 23321787 PMCID: PMC3618397 DOI: 10.1038/jcbfm.2012.210] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/26/2012] [Revised: 12/02/2012] [Accepted: 12/08/2012] [Indexed: 12/21/2022]
Abstract
The adaptation of the cerebral circulation to pregnancy is unique from other vascular beds. Most notably, the growth and vasodilatory response to high levels of circulating growth factors and cytokines that promote substantial hemodynamic changes in other vascular beds is limited in the cerebral circulation. This is accomplished through several mechanisms, including downregulation of key receptors and transcription factors, and production of circulating factors that counteract the vasodilatory effects of vascular endothelial growth factor (VEGF) and placental growth factor. Pregnancy both prevents and reverses hypertensive inward remodeling of cerebral arteries, possibly through downregulation of the angiotensin type 1 receptor. The blood-brain barrier (BBB) importantly adapts to pregnancy by preventing the passage of seizure provoking serum into the brain and limiting the permeability effects of VEGF that is more highly expressed in cerebral vasculature during pregnancy. While the adaptation of the cerebral circulation to pregnancy provides for relatively normal cerebral blood flow and BBB properties in the face of substantial cardiovascular changes and high levels of circulating factors, under pathologic conditions, these adaptations appear to promote greater brain injury, including edema formation during acute hypertension, and greater sensitivity to bacterial endotoxin.
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Affiliation(s)
- Marilyn J Cipolla
- Departments of Neurological Sciences, Obstetrics, Gynecology and Reproductive Sciences, Pharmacology, University of Vermont College of Medicine, Burlington, VT, USA.
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Affiliation(s)
- Marilyn J Cipolla
- Department of Neurology, University of Vermont College of Medicine, Burlington, VT 05405, USA.
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Riskin-Mashiah S, Belfort MA. Preeclampsia is associated with global cerebral hemodynamic changes. ACTA ACUST UNITED AC 2006; 12:253-6. [PMID: 15866116 DOI: 10.1016/j.jsgi.2005.01.002] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
OBJECTIVE To compare blood flow-velocity parameters in the anterior and posterior cerebral arteries between normotensive and preeclamptic pregnant women. METHODS Transcranial Doppler ultrasound was used to measure peak, end-diastolic, and mean velocities in the anterior cerebral artery (ACA) and posterior cerebral artery (PCA) of 22 normotensive and 12 preeclamptic women in the third trimester. All measurements were performed with the subject in the left lateral position. Blood pressure and heart rate were recorded with each Doppler measurement. The mean pulsatility index (PI), resistance index (RI), and cerebral perfusion pressure for each artery was averaged and compared. Statistical significance was set at P <.05. RESULTS Preeclamptic women had higher cerebral perfusion pressure in both ACA and PCA (64.7 +/- 5.9 and 78.1 +/- 7.6 compared with 42.4 +/- 2.6 and 54.1 +/- 4.1 mmHg, P <.05), lower PI (0.83 +/- 0.05 and 0.71 +/- 0.04 compared with 0.96 +/- 0.04 and 0.84 +/- 0.02, P <.05), and lower RI (0.55 +/- 0.02 and 0.49 +/- 0.02 compared with 0.60 +/- 0.02 and 0.55 +/- 0.01, P <.05) than normotensive pregnant women. CONCLUSION Preeclamptic patients have globally elevated cerebral perfusion pressure and lower resistance in the cerebral circulation than normotensive pregnant women.
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Affiliation(s)
- Shlomit Riskin-Mashiah
- Department of Obstetrics and Gynecology, Baylor College of Medicine, Houston, Texas, USA.
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Riskin-Mashiah S, Belfort MA. Cerebrovascular hemodynamics in chronic hypertensive pregnant women who later develop superimposed preeclampsia. ACTA ACUST UNITED AC 2005; 12:28-32. [PMID: 15629667 DOI: 10.1016/j.jsgi.2004.08.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
OBJECTIVE We have previously shown that normotensive pregnant women who later develop preeclampsia demonstrate lower baseline pulsatility index (PI) and resistance index (RI) but normal vasodilatory responses to stimulation tests. In the current study, we tested the hypothesis that women with chronic hypertension who later developed superimposed preeclampsia behave similarly. METHODS Transcranial Doppler ultrasound was performed on 17 women with chronic hypertension during the second trimester of pregnancy to measure middle cerebral artery (MCA) velocities. Superimposed preeclampsia developed in seven patients (SUPER group) while the rest did not develop preeclampsia (CHT group). Measurements were performed in the left lateral position at baseline on room air, during 5% CO2 inhalation, and during a 2-minute isometric handgrip test. Blood pressure, heart rate, O2 saturation, and end-tidal PCO2 were recorded with each Doppler measurement. Mean PI, RI, and cerebral perfusion pressure (CPP) at each time were compared using two-way repeated measures analysis of variance. Statistical significance was set at P < .05. RESULTS The women who developed superimposed preeclampsia did this an average of 8.7 +/- 1.3 weeks after the study. MCA PI and RI were lower, and CPP higher, in the SUPER group compared to the CHT group (0.64, 0.46, and 80.7 vs 0.74, 0.51, and 63.6, respectively; P < .05). Both maneuvers caused reduction in MCA PI and RI in both groups, whereas CPP increased only in the SUPER group. CONCLUSIONS These findings suggest that women destined to develop preeclampsia have cerebral hemodynamic changes that predate the development of overt preeclampsia.
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Affiliation(s)
- Shlomit Riskin-Mashiah
- Department of Obstetrics and Gynecology, Baylor College of Medicine, Houston, Texas, USA.
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Riskin-Mashiah S, Belfort MA. Cerebrovascular Hemodynamics in Pregnant Women With Mild Chronic Hypertension. Obstet Gynecol 2004; 103:294-8. [PMID: 14754698 DOI: 10.1097/01.aog.0000110250.48579.21] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
OBJECTIVE To evaluate and compare the cerebrovascular autoregulation in pregnant normotensive and mild chronic hypertensive patients without preeclampsia. METHODS Transcranial Doppler ultrasound was used to measure peak, end-diastolic, and mean velocities in the middle cerebral arteries of 34 normotensive and 17 mild chronic hypertensive women in the third trimester of pregnancy. Measurements were performed in the left lateral position at baseline, during 5% CO(2) inhalation, and during an isometric handgrip test. Mean pulsatility index, resistance index, and cerebral perfusion pressure at each time were compared using 2-way repeated measures analysis of variance. Using an alpha error of 5%, the statistical power to identify differences in middle cerebral artery indices in response to the two maneuvers was at least 90% and 50% in comparison between the two groups. Significance was P <.05. RESULTS Pregnant women with mild chronic hypertension had higher baseline mean blood pressure but similar pulsatility index (0.73 versus 0.75), resistance index (0.50 versus 0.50), and cerebral perfusion pressure (59.9 versus 61.8 mm Hg) compared with normotensive pregnant women. Both maneuvers caused a significant reduction in pulsatility index and resistance index and higher cerebral perfusion pressure. No significant differences were noted in the response to either 5% CO(2) inhalation or isometric handgrip test between the two groups. CONCLUSION Pregnant women with mild chronic hypertension show normal cerebral vasomotor reactivity to CO(2) breathing and isometric handgrip. This suggests that the abnormal cerebrovascular autoregulation in preeclampsia is not directly linked to the elevated blood pressure but rather is determined by a separate pathophysiologic pathway. LEVEL OF EVIDENCE II-2
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Affiliation(s)
- Shlomit Riskin-Mashiah
- Department of Obstetrics and Gynecology, Baylor College of Medicine, Houston, Texas, USA.
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Riskin-Mashiah S, Belfort MA, Saade GR, Herd AJ. Side-to-side differences in transcranial Doppler parameters in normotensive and preeclamptic pregnant women. Am J Obstet Gynecol 2004; 190:194-8. [PMID: 14749659 DOI: 10.1016/j.ajog.2003.07.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
OBJECTIVE This study was undertaken to investigate whether women with preeclampsia demonstrate larger side-to-side velocity differences in the middle cerebral artery (MCA) compared with normotensive pregnant women. STUDY DESIGN Forty-one preeclamptic women and 50 normotensive pregnant women were studied during the third trimester. Transcranial Doppler ultrasound was used to measure peak, end-diastolic, and mean velocities in both MCAs. An asymmetry index was calculated as 100 x Rt-Lt//(Rt+Lt)/2, for each of the following parameters: mean velocity (Vm), pulsatility index (PI), and cerebral perfusion pressure (CPP). Student t test, Pearson correlation, and regression analysis were used. Significance was taken as P<.05. RESULTS Both normotensive and preeclamptic pregnant women showed good correlation between Rt and Lt MCA Vm (R>0.8, P<.0001), PI (R>0.6, P.0001), and CPP (R>0.8, P<.0001). There were no differences in the asymmetry index for Vm, PI, or CPP between the two groups. CONCLUSION Preeclampsia does not appear to induce greater side-to-side velocity differences in the MCA distribution.
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Abstract
OBJECTIVE This study was undertaken to determine blood flow changes in the large cerebral arteries during normal pregnancy. STUDY DESIGN Ten healthy pregnant volunteers underwent velocity-encoded phase contrast magnetic resonance imaging at 4 time intervals: 14 to 16, 28 to 32, and 36 to 38 weeks' gestation, and at 6 to 8 weeks' postpartum. Analysis consisted of serial paired Student t tests, with P<.05 considered significant. RESULTS By using postpartum values for comparison, cerebral blood flow decreased by 14 to 16 weeks in the middle cerebral artery (P<.001), but was not significantly changed in the posterior cerebral artery. Significant decreases occurred in both the middle (P<.0001) and posterior (P=.002) cerebral arteries in late pregnancy. CONCLUSION An approximately 20% reduction in large artery cerebral blood flow occurs during normal pregnancy, secondary to changes in velocity, whereas the area of these vessels remains unchanged. These findings may represent generalized vasodilatation of downstream resistance arterioles, assuming constant blood flow at the tissue level.
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Affiliation(s)
- Gerda G Zeeman
- Department of Obstetrics and Gynecology, University of Texas Southwestern Medical Center, Dallas, Texas, USA.
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Belfort MA, Tooke-Miller C, Allen JC, Saade GR, Dildy GA, Grunewald C, Nisell H, Herd JA. Changes in flow velocity, resistance indices, and cerebral perfusion pressure in the maternal middle cerebral artery distribution during normal pregnancy. Acta Obstet Gynecol Scand 2001. [DOI: 10.1034/j.1600-0412.2001.080002104.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Zatik J, Major T, Aranyosi J, Molnár C, Limburg M, Fülesdi B. Assessment of cerebral hemodynamics during roll over test in healthy pregnant women and those with pre-eclampsia. BJOG 2001; 108:353-8. [PMID: 11305540 DOI: 10.1111/j.1471-0528.2001.00095.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
OBJECTIVE To compare cerebral autoregulatory responses obtained during roll over tests in healthy pregnant women and those with pre-eclampsia in order to assess the middle cerebral artery velocity changes in relation to the roll over test in normotensive and pre-eclamptic women. PARTICIPANTS Twenty-two healthy pregnant women and 26 with pre-eclampsia underwent transcranial Doppler measurements of the middle cerebral artery. METHODS Systolic, mean and diastolic blood flow velocities and mean arterial blood pressures were recorded in the left lateral position and five minutes after turning to the supine position. Absolute values of mean blood flow velocities, mean arterial blood pressure values and calculated cerebral blood flow indices as well as cerebrovascular resistance area products were compared at different positions among the groups. RESULTS Mean arterial blood pressure increased in both groups while turning from the left lateral to the supine position. In women with pre-eclampsia both mean arterial blood pressure and absolute values of mean blood flow velocity values were higher in both positions, compared with healthy pregnant women. In both groups, changing the position resulted in a decrease of absolute values of mean blood flow velocities. Calculated cerebral blood flow indices did not change, while cerebrovascular resistance area products increased significantly in the groups during roll over testing. In women with pre-eclampsia, the increase of cerebrovascular resistance area products was more pronounced as compared with healthy pregnant women. CONCLUSIONS In women with pre-eclampsia roll over test results in an increase of the mean arterial blood pressure, which is accompanied by a decreased mean blood flow velocity in the middle cerebral artery. Further studies are needed to clarify the pathophysiological background of cerebral haemodynamic changes in pre-eclampsia.
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Affiliation(s)
- J Zatik
- Department of Obstetrics and Gynaecology, University of Debrecen Medical Centre, Hungary
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