| 1. |
- Svensson, Christina, 1964-
(author)
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Ultrasound Assessment and Vascular Mechanics in Takayasu Arteritis and Systemic Lupus Erythematosus
- 2023
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Doctoral thesis (other academic/artistic)abstract
- Takayasu arteritis (TAK) and systemic lupus erythematosus (SLE) are inflammatory diseases that primarily affect young women. TAK is a rare vasculitis that affects the aorta and its main branches, whereas SLE is a chronic autoimmune disease that effects multiple organs. Both diseases are associated with premature cardiovascular disease (CVD), and a wish to understand these associations prompted the studies of this thesis.The macrocirculation, microcirculation and vascular haemodynamics were studied in patients with TAK (N=25 in Paper I, N=17 in Paper II) and SLE (N=60 in Papers III and IV), and compared with age- and gender-matched controls. Vessel wall thickness (intima-media thickness (IMT)), vessel wall appearance, and occurrence of atherosclerotic plaques were evaluated in multiple vascular areas using high-frequency ultrasound (US). Microcirculation in the skin was studied after induced ischaemia employing a new method that combines laser Doppler flowmetry (LDF) and diffuse reflectance spectroscopy (DRS). The measured microcirculatory value was defined as the peak oxygen saturation (OxyP). Pulse wave analysis was used for calculation of the central augmentation index (AIx). Cerebrovascular reserve capacity (CVR) was analysed using transcranial Doppler (TCD).Paper IIn this study, TAK patients were examined with US, including follow-up studies. Clinically active cases of TAK showed significantly increased IMT compared to stable patients with TAK and healthy controls. The arteries of patients with active disease showed signs of intra-mural micro-vessels, oedema, or increased vessel diameter, whereas these signs were not seen in cases of stable disease. The Takayasu US index (based on the summation of the IMT in three arterial areas) was higher in active disease than in stable disease, and was valuable for the assessment of relapse.Paper IIIn this study of vascular haemodynamics in patients with TAK we observed impaired microcirculation, as compared with controls. CVR was preserved regardless of proximal arterial stenosis. The AIx, reflecting arterial stiffness, was increased, also in the arms without proximal stenosis or occlusion.Papers III and IVIncreased IMT with predominantly medium echogenicity was observed in multiple arteries of the 60 patients with SLE, predominantly in vascular areas that are not usually part of the IMT measurements. The patients with SLE developed plaques more frequently and earlier in life compared to the controls. Correlation with traditional cardiovascular risk factors was observed, indicating atherosclerotic mechanisms rather than inflammation. The patients with SLE had higher AIx values and lower OxyP levels, even at younger ages, and both these methods correlated with the IMT and plaque occurrence.ConclusionsFor patients with TAK, US can be valuable both for the diagnosis of the disease and for distinguishing between the active and stable disease forms. The microcirculation and degree of arterial stiffness in the arms are affected also in patients with TAK without proximal stenosis/occlusion, indicating a more widespread arterial wall dysfunction.In patients with SLE, increased IMT, an affected microcirculation, increased arterial stiffness, and premature atherosclerotic plaques indicate vascular affection coupled with increased risk for cardiovascular disease. All these evaluated methods may be used for longitudinal studies with or without intervention.
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| 2. |
- Svensson, Christina, 1964-, et al.
(author)
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Vascular ultrasound for monitoring of inflammatory activity in Takayasu arteritis
- 2020
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In: Clinical Physiology and Functional Imaging. - : WILEY. - 1475-0961 .- 1475-097X. ; 40:1, s. 37-45
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Journal article (peer-reviewed)abstract
- Background Takayasu arteritis (TA) is a rare large-vessel arteritis that primarily affects the aorta and its major branches. The aim of this study was to describe the value of high frequency ultrasound for monitoring of inflammatory activity. Methods Twenty-five patients, range 11-71 years, diagnosed with TA were investigated with duplex ultrasound (DUS) including follow-up studies. Twenty-five healthy controls were also investigated. Nine patients had newly diagnosed active TA. Sixteen patients had stable/inactive disease at baseline DUS, and TA was diagnosed median 4 center dot 5 years previously. Intima-media thickness (IMT), vessel and lumen diameter were measured in the carotid arteries, central neck arteries and the aortic arch. The vessel walls were studied qualitatively. The Takayasu ultrasound index was created for inflammatory activity scoring. Results Intima-media thickness in common carotid artery (CCA) was (median and 25-75 percentile parenthetic) 2 center dot 3 mm (1 center dot 7-2 center dot 9) in clinically active TA, 1 center dot 2 mm (1 center dot 1-1 center dot 6) in clinically stable TA (Pamp;lt;0 center dot 001) and 0 center dot 5 mm (0 center dot 5-0 center dot 6) in healthy controls (Pamp;lt;0 center dot 001). Clinically active TA had prominent increase in IMT and/or increased vessel diameter, and/or intramural arteries, and/or hypoechogenic areas interpreted as oedema in the vessel wall. TA in clinical remission was characterized by increased IMT with medium to high echogenicity with or without fibrotic stripes. The Takayasu ultrasound index was higher in patients with active disease versus treated disease, 2 center dot 55 (1 center dot 60-3 center dot 05) versus 1 center dot 30 (1 center dot 00-1 center dot 58), (P = 0 center dot 003). Conclusion DUS is an excellent tool to monitor inflammatory changes in the vessel wall in TA. Further DUS studies in larger patient populations are warranted.
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| 5. |
- Georgiopoulos, Charalampos, 1984-
(author)
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Imaging Studies of Olfaction in Health and Parkinsonism
- 2019
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Doctoral thesis (other academic/artistic)abstract
- Olfactory loss is a common non-motor symptom of Parkinson’s disease (PD), often preceding the cardinal motor symptoms of the disease. The aim of this thesis was to: (a) evaluate whether olfactory examination can increase diagnostic accuracy, and (b) study the structural and functional neural basis of olfactory dysfunction in PD with different applications of Magnetic Resonance Imaging (MRI).Paper I was a comparison of the diagnostic accuracy between a simple smell identification test and DaTSCAN Single Photon Emission Computerized Tomography (SPECT), a nuclear medicine tomographic imaging technique that is commonly used in patients with suspected parkinsonism. The results indicate that smell test is inferior to DaTSCAN SPECT, but the combination of these two methods can lead to improved diagnostic accuracy.Paper II showed that diffusion MRI could detect discrete microstructural changes in the white matter of brain areas that participate in higher order olfactory neurotransmission, whereas MRI with Magnetization Transfer contrast could not.Paper III was a methodological study on how two different acquisition parameters can affect the activation pattern of olfactory brain areas, as observed with functional MRI (fMRI). The results indicate that brief olfactory stimulation and fast sampling rate should be preferred on olfactory fMRI studies.Paper IV used olfactory fMRI and resting-state fMRI in order to elucidate potentially altered activation patterns and functional connectivity within olfactory brain areas, between PD patients and healthy controls. Olfactory fMRI showed that olfactory impairment in PD is associated with significantly lower recruitment of the olfactory network. Resting-state fMRI did not detect any significant changes in the functional connectivity within the olfactory network of PD patients.In conclusion, the included studies provide evidence of: (a) disease-related structural and functional changes in olfactory brain areas, and (b) beneficial addition of olfactory tests in the clinical work-up of patients with parkinsonism.
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| 8. |
- Hultman, Martin, 1992-, et al.
(author)
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Comprehensive imaging of microcirculatory changes in the foot during endovascular intervention - A technical feasibility study
- 2022
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In: Microvascular Research. - Maryland Heights, MO, United States : Academic Press. - 0026-2862 .- 1095-9319. ; 141
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Journal article (peer-reviewed)abstract
- Chronic limb-threatening ischemia (CLTI) has a major impact on patient's lives and is associated with a heavy health care burden with high morbidity and mortality. Treatment by endovascular intervention is mostly based on macrocirculatory information from angiography and does not consider the microcirculation. Despite successful endovascular intervention according to angiographic criteria, a proportion of patients fail to heal ischemic lesions. This might be due to impaired microvascular perfusion and variations in the supply to different angiosomes. Non-invasive optical techniques for microcirculatory perfusion and oxygen saturation imaging have the potential to provide the interventionist with additional information in real-time, supporting clinical decisions during the intervention. This study presents a novel multimodal imaging system, based on multi-exposure laser speckle contrast imaging and multi-spectral imaging, for continuous use during endovascular intervention. The results during intervention display spatiotemporal changes in the microcirculation compatible with expected physiological reactions during balloon dilation, with initially induced ischemia followed by a restored perfusion, and local administration of a vasodilator inducing hyperemia. We also present perioperative and postoperative follow-up measurements with a pulsatile microcirculation perfusion. Finally, cases of spatial heterogeneity in the observed oxygen saturation and perfusion are discussed. In conclusion, this technical feasibility study shows the potential of the methodology to characterize changes in microcirculation before, during, and after endovascular intervention.
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| 11. |
- Nelzén, Oskar, 1984-, et al.
(author)
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Impact on venous haemodynamics after treatment of great saphenous vein incompetence using plethysmography and duplex ultrasound
- 2020
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In: Phlebology. - : Sage Publications. - 0268-3555 .- 1758-1125. ; 35:7, s. 495-504
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Journal article (peer-reviewed)abstract
- ObjectivesTo evaluate postoperative venous haemodynamics and quality of life after treatment of great saphenous vein (GSV) incompetence.MethodsRadiofrequency ablation and high ligation and stripping were performed in 62 patients (65 limbs) and 58 (65 limbs), respectively. Phlebectomies were performed in both modalities. Strain-gauge plethysmography on the foot combined with superficial venous occlusion was used to measure refilling time after knee bends. Strain-gauge plethysmography, duplex ultrasound and quality of life were assessed before and one month after treatment.ResultsDuplex ultrasound displayed successful intervention in all but two limbs. Refilling time increased similar in radiofrequency ablation and high ligation and stripping after treatment (p < 0.001). Postoperatively, strain-gauge plethysmography detected remaining reflux in 71% of the patients. Multivariate analysis showed that two or more incompetent calf branches were associated with remaining reflux (OR 4.82 (95% CI: 1.33–17.5), p = 0.02). No difference in quality of life was seen in patients with remaining reflux.ConclusionsDespite successful treatment, a majority of the limbs showed remaining reflux, in which incompetent calf branches appear to play an important role.Clinicaltials.gov: Lower Limb Venous Insufficiency and the Effect of Radiofrequency Treatment Versus Open Surgery. Nr: NCT02397226
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| 12. |
- Nelzén, Oskar, 1984-
(author)
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Lower limb venous incompetence and the effect of radiofrequency ablation versus open surgery : Focus on haemodynamics, quality of life and health economic aspects
- 2023
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Doctoral thesis (other academic/artistic)abstract
- Chronic venous incompetence (CVI) is a common condition, and varicose vein treatment is one of the most-common surgical procedures performed worldwide. Common symptoms of CVI are pain, cramps, itching, feeling of leg heaviness and venous claudication. Advanced CVI can lead to skin changes, eczema and venous ulcers. While the cause of the disease is un-known, it often starts with venous enlargement and valve dysfunction. The overall aims of this thesis are: 1) to develop quantitative diagnostic measurements using strain-gauge plethysmography (SGP) with standardised superficial venous occlusion and duplex ultrasound (DUS); 2) to evaluate the effects of radiofrequency ablation (RFA) and high ligation/stripping (HL/S) for patients with great saphenous vein (GSV) incompetence; and 3) to evaluate the cost-effectiveness of GSV treatment. The first of the four studies involved patients with GSV incompetence. For these patients, SGP with superficial venous occlusion was performed before and after GSV treatment. SGP was able to predict the haemodynamic outcome of the treatment in the majority of the limbs examined. The conclusion is that SGP with standardised superficial venous occlusion may be used for predicting the outcome of GSV treatment. The second study evaluated the short-term outcomes of GSV treatment using RFA and HL/S regarding haemodynamics and quality of life (QoL). Both treatments lead to significant improvements in QoL, with no signifcant differences between the treatments. Despite successful treatment, the majority of the limbs in both treatment groups had significant residual reflux located mainly in the calf (i.e., below the treated area). The residual reflux may be a risk factor for future symptom relapses and need to be examined in more-long-term studies. The third study examined quantitative DUS and SGP parameters in relation to clinical severity and QoL. DUS-derived volume flow and SGP re-flux time showed weak but significant correlations with clinical severity (C in CEAP). The conclusion is that the current gold standard using the qualitative DUS-derived reflux time for CVI diagnostics should be revised and replaced with a more-relevant quantitative parameter. The fourth study evaluated the cost-effectiveness of GSV treatment with 1 year of follow-up. Both RFA and HL/S provided significant improvements in QoL. RFA is very cost-effective and is associated with fewer days missed from work compared to HL/S. Cost-wise, both methods are well be-low the national threshold for cost-effective treatment. Due to its higher cost, HL/S should be reserved for cases that require this method.
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| 13. |
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| 14. |
- Nelzén, Oskar, 1984-, et al.
(author)
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Short Term Cost Effectiveness of Radiofrequency Ablation and High Ligation and Stripping for Great Saphenous Vein Incompetence
- 2024
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In: European Journal of Vascular and Endovascular Surgery. - : Elsevier. - 1078-5884 .- 1532-2165. ; 67:5, s. 811-817
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Journal article (peer-reviewed)abstract
- Objective: Superficial venous incompetence (SVI) is a common disease that causes significant quality of life (QoL) impairment. There is a need for more health economic evaluations of SVI treatment. The aim of this study was to perform a cost effectiveness analysis in patients with great saphenous vein (GSV) incompetence comparing radiofrequency ablation (RFA), high ligation and stripping (HL/S), and no treatment or conservative treatment with one year follow up.Methods: Randomised controlled trial economic analysis from an ongoing trial; 143 patients (156 limbs) with GSV incompetence (C in CEAP 2 - 6) were included. Treatment was performed with RFA or HL/S. Follow up was performed up to one year using duplex ultrasound, revised venous clinical severity score (r-VCSS), Aberdeen Varicose Vein Questionnaire (AVVQ), and EuroQol-5D-3L (EQ-5D-3L).Results: Seventy-eight limbs were treated with RFA and HL/S respectively. No treatment or conservative treatment was assumed to have zero in treatment cost and no treatment benefit. In the RFA group, one limb had reflux in the GSV after one month and three limbs after one year. In HL/S, two limbs had remaining reflux in the treated area at one month and one year. Both disease severity (r-VCSS, p = .004) and QoL (AVVQ, p = .021 and EQ-5D-3L, p = .028) were significantly improved over time. The QALY gain was 0.21 for RFA and 0.17 for HL/S. The cost per patient was calculated as €1 292 for RFA and €2 303 for HL/S. The cost per QALY (compared with no treatment or conservative treatment) was €6 155 for RFA and €13 549 for HL/S. With added cost for days absent from work the cost per QALY was €7 358 for RFA and €24 197 for HL/S. The cost per QALY for both methods was well below the threshold suggested by Swedish National Board of Health.Conclusion: RFA is more cost effective than HL/S and no treatment or conservative treatment at one year follow up.
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| 15. |
- Persson, Anders, 1953-, et al.
(author)
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Advances of dual source, dual-energy imaging in postmortem CT
- 2008
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In: European Journal of Radiology. - : Elsevier BV. - 0720-048X .- 1872-7727. ; 68:3, s. 446-455
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Journal article (peer-reviewed)abstract
- This paper focuses on the use of multi-detector row dual-energy computed tomography (DECT) in the evaluation of postmortal examinations. The use of dual energy moves postmortem CT to an entirely new dimension of diagnostic sensitivity where contrast in the image is not merely limited to X-ray attenuation differences, but may include elements of functional and tissue characterization. This additional information may be used to improve the benefit postmortem imaging can provide to supplement and simplify the conventional autopsy. © 2008 Elsevier Ireland Ltd. All rights reserved.
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| 16. |
- Skoog, Johan, 1977-, et al.
(author)
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Venous Compliance in Great Saphenous Vein Incompetence : Pre- and Post-interventional Changes
- 2020
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In: EJVES Vascular Forum. - : Elsevier. - 2666-688X. ; 47, s. 78-82
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Journal article (peer-reviewed)abstract
- Objective: Venous insufficiency is associated with histological changes and structural remodelling of the venous wall. The effects of these changes on global venous function remain uncertain. The aim was to evaluate venous compliance in patients with great saphenous vein (GSV) insufficiency before and after treatment by radiofrequency ablation (RFA) and in controls.Methods: Eleven patients (14 limbs) underwent endovenous RFA treatment for GSV incompetence. Duplex ultrasound and strain gauge plethysmography (SGP) were performed before and after RFA. SGP time (seconds) to reach 50% of maximum venous volume (T50) with and without superficial occlusion was used to assess global venous reflux. Venous occlusion plethysmography was used to evaluate pre- and post-operative calf venous compliance. Venous compliance was also assessed in 12 age and sex matched controls.Results: Pre-operative calf venous compliance was lower in patients than in controls (p < .001). Post-operative calf venous compliance was reduced vs. pre-operative measurements (p < .002). The pre-operative reflux parameter T50 improved from 8.0 ± 2.0 seconds to 17.3 ± 1.9 seconds (p < .001) after RFA. The post-operative T50 without superficial occlusion was similar to pre-operative T50 with superficial occlusion (17.1 ± 2.5 vs. 17.3 ± 1.9 seconds, p = .84).Conclusions: Calf venous compliance is reduced in patients with GSV insufficiency. Venous reflux parameters markedly improved after RFA, whereas venous compliance displayed a further reduction vs. the pre-operative state, implicating generalised changes in the lower limb venous vessel wall.Previous article in issue
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| 17. |
- Svensson, Christine, et al.
(author)
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Nutcracker Syndrome, vascular imaging with ultrasound
- 2018
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In: Cardiovasc Pharm Open Access. - Los Angeles, CA, United States : Omics Publishing Group. - 2329-6607. ; 7:2
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Journal article (peer-reviewed)abstract
- Nutcracker Syndrome (NCS) or Left Renal Vein (LRV) entrapment is rare and may be caused by compression of the vein between the aorta and the Superior Mesenteric Artery (SMA). LRV hypertension may lead to varicosities. The syndrome is characterized by a complex of symptoms with substantial variations, the diagnosis is difficult and therefor often delayed. The diagnosis may be settled by many imaging methods, such as renal angiography, retrograde phlebography, Computed Tomography (CT), Magnetic Resonance Imaging (MRI) and Doppler Ultrasonography (DUS). The degree of stenosis may be detected measuring Doppler flow velocities by DUS.A 50-year old female with Crohn´s disease treated by ileocecal resection, performed 20 years ago, and symptomatic epilepsy treated by a vagal stimulator, had newly added symptoms of abdominal pain, weight loss, dizziness, irregular bowel movements, and increasing fatigue. Blood parameters and physical examination were normal. CT showed no signs of active Crohn´s disease. The left renal veins and the left ovarian vein were dilated and the aorto-mesenteric angle was only 22 degrees.DUS (Siemens S2000, 6 and 9 MHz transducers) performed one month later confirmed the findings of the CT with typical findings of NCS. DUS will play a crucial role in Nutcracker syndrome considering flow velocity, diameter measurement, anatomy and aorto-mesenteric angle. DUS is a non-invasive, cheap modality that gives a very good resolution that can define vessel walls and evaluate flow velocity conditions. This patient had mild symptoms that led to a conservative treatment whereas epilepsy and Crohn ́s disease was the main problem. If severe symptoms occur different kinds of treatments are available, such as stenting of LRV, open surgical interventions, ablation of collateral pelvic veins and coil embolization.
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| 18. |
- Zachrisson, Helene, et al.
(author)
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An extended high-frequency ultrasound protocol for detection of vessel wall inflammation.
- 2018
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In: Clinical Physiology and Functional Imaging. - : John Wiley & Sons. - 1475-0961 .- 1475-097X. ; 38:4, s. 586-594
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Journal article (peer-reviewed)abstract
- OBJECTIVE: The aim of this study was to evaluate an extended protocol of the large vessels using high-frequency duplex ultrasound (DUS) for detection of vessel wall inflammation.METHODS: Fifty-eight patients performed a DUS examination where arteritis could not be excluded. All DUS examinations were performed using ACUSON S2000 TM ultrasound system (Siemens Medical Solutions USA, Inc.). High-frequency linear transducers were used (18L6 MHz, 9L4MHz) or curve linear for the aortic arch (6C2 MHz). Carotid, vertebral, central neck arteries (subclavian, axillary, innominate) arteries, aortic arch and femoral arteries were studied. Circumferential, homogenous wall thickening, with or without a hyperechogenic stripe lining the innermost layer, were regarded as typical signs of arteritis. Intima-media thickness (IMT) was measured in the patients and a normal control group. The latest clinical updated diagnosis was assessed at least 6 months after DUS.RESULTS: The DUS findings showed normal vessels (n = 14), arteritis and atherosclerosis (n = 13), atherosclerosis (n = 15) and arteritis (n = 16). The latter group had a significant increased IMT in the common femoral artery and the common carotid artery (mean 1·0 ± SD 0·3 mm versus 0·6 ± 0·2 mm in the normal group (n = 37), P<0·00001, 1·2 ± 0·5 mm versus 0·8 ± 0·2 mm in the normal group (n = 40), P<0·00001). In the groups with sonographic signs implying arteritis (n = 29), 20 patients had a clinical diagnosis of arteritis, whereas eight patients had another main diagnosis such as malignancy/other inflammatory or infectious disease complicated by inflammation of the vessel wall. One patient had multiple diagnoses and was not possible to classify.CONCLUSION: An extended ultrasound protocol for central neck and leg arteries could be of value for diagnosis of arteritis. In case of atypical vessel wall inflammation, other main diagnoses should be considered.
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| 19. |
- Zachrisson, Helene, 1964-
(author)
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Biomedicinska analytiker är nyckelspelare
- 2018
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In: Dagens medicin. - Stockholm : Bonnier Business Media AB. - 1104-7488.
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Journal article (other academic/artistic)abstract
- Snabbspår med ultraljudsundersökning är långt ifrån standard, trots att metoden visat sig vara viktig för att snabbt ställa diagnosen jättecellsarterit. I Linköping har man redan infört en fungerande modell.
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| 24. |
- Zachrisson, Helene, 1964-, et al.
(author)
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Estimation of Superficial Venous Reflux with Duplex Ultrasound and Foot Volumetry
- 2019
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In: Juniper Online Journal of Case Studies. - : Juniper Publishers. - 2476-1370. ; 10:1, s. 1-5
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Journal article (peer-reviewed)abstract
- Objective: To evaluate quantitative duplex ultrasound (DUS) parameters of reflux in patients with isolated great saphenous vein insufficiency.Methods: 20 limbs were studied. DUS derived reflux time (RT, sec), peak reflux velocity (PRV, cm/s) and reflux volume flow (ml/min) were evaluated and related to expelled volume (EV, ml) and half refilling time (T50, sec) measured by water-based foot volumetry with and without compression of superficial veins.Results: Reflux volume flow correlated significantly to all hemodynamic parameters assessed by foot volumetry, i.e., EV (p = 0.003), ΔEV (p = 0.006), T50 (p = 0.004) and ΔT50 (p = 0.011). PRV displayed a weaker correlation to foot volumetry parameters EV (p = 0.027) and T50 (p = 0.008). No significant correlation was found between RT and foot volumetry.Conclusion: These results indicate that reflux volume flow may be a potential parameter in future attempts to quantify reflux using DUS in patients with isolated great saphenous vein insufficiency.
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| 25. |
- Zachrisson, Helene, 1964-
(author)
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Noninvasive assessment of cerebral circulation before, during and after carotid surgery
- 2000
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Doctoral thesis (other academic/artistic)abstract
- Non-invasive ultrasound investigations were evaluated in patients with carotid artery stenosis in comparison with radiological disease gradations and perioperative blood pressure measurements. The aim was to assess cerebrovascular hemodynamics before, during and after carotid thrombendarterectomy (CEA) in relation to the clinical outcome of the surgical intervention.Intracranial collateral blood flow as a consequence of high grade carotid artery disease can be investigated by means of blood flow velocity measurements with 3D-transcranial Doppler flow mapping and proximal common carotid artery compressions. The value and risks of common carotid artery compression were therefore assessed. No adverse effects were seen in 3383 patient studies retrospectively reviewed. In addition, we found that transcranial Doppler without carotid compression may lead to false identification of the posterior cerebral artery.Preoperative blood flow velocities within the carotid stenosis and poststenotic blood pressures during intraoperative carotid clamping were analysed with respect to some serious postoperative complications. We found that blood flow velocities within severe internal carotid artery (ICA) stenoses are inversely related to the poststenotic collateral blood pressure. High diastolic blood flow velocities within the ICA stenosis might indicate low collateral blood pressures and increased risk for severe postoperative neurological complications. The discrepancies occasionally seen between preoperative ultrasound investigation and angiography might therefore be explained by high collateral backpressures, which may induce unusually low blood flow velocities within severe ICA diameter reductions.The carotid compression test, performed during the preoperative transcranial Doppler investigation, was used to predict middle cerebral artery (MCA) blood flow reductions during intraoperative carotid artery cross-clamping. Surprisingly, we found a greater decrease of the MCA blood flow velocities during the carotid compression test compared with the flow changes during cross-clamping. Signs of cerebrovascular autoregulation due to carotid compression were not reproducible during carotid clamping under general anaesthesia. The few patients with postoperative adverse reactions happened to show a pattern of low collateral blood pressures and relatively high MCA blood flow velocities during cross-clamping. Since general anaesthesia affects cerebral autoregulation we performed a postoperative transcranial Doppler study to assess the MCA blood flow pattern after surgical restoration of normal ICA blood flow. In the majority of the patients, we observed increased blood flow velocities bilaterally within the MCA, which might be a result of postoperative hyperperfusion or autonomic imbalance of carotid sinus baroreceptors.In conclusion, evaluations of cerebrovascular hemodynamics in CEA patients might give important information indicating risks of complications.
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| 26. |
- Zachrisson, Helene, 1964-
(author)
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Transkraniell doppler/duplex
- 2002
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In: Klinisk fysiologisk kärldiagnostik. - Lund : Studentlitteratur AB. - 9789144021898 ; , s. 212-221
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Book chapter (other academic/artistic)
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