| 1. |
- Boivie, Patrik, et al.
(författare)
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Size distribution of embolic material produced at aortic cross-clamp manipulation
- 2010
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Ingår i: Scandinavian Cardiovascular Journal. - London, UK : Informa Plc.. - 1401-7431 .- 1651-2006. ; 44:6, s. 367-372
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Tidskriftsartikel (refereegranskat)abstract
- Objectives: The association between aortic atherosclerosis and neurological damage during cardiac surgery is well recognized. The purpose was here to analyze the size distribution of particles produced at cross-clamp manipulation of the ascending aorta. Design: A human cadaveric aortic perfusion model of retrograde design was applied (n 27). With this model, washout samples were collected from the pressurized ascending aorta during cross clamp manipulation. Before the experiment, the aorta was flushed to remove debris and with a baseline sample collected. The cross-clamp was opened to collect ten repeated aliquots with dislodged particles. Collected washout samples were evaluated by digital image analysis and microscopy. Results: Cross-clamping produced a significant output of particles, which was seen for size intervals of 1 mm and smaller (p 0.002 to p 0.022). In all size intervals the particle output correlated with the degree of overall aortic calcification(p 0.002 to p 0.025). The model generated substantially more small-size particles than large debris (p 0.010). Conclusions: Aortic clamping was here verified to dislodge aortic debris which correlated with the degree of observed calcification. Macroscopic particles were few. In contrast, cross-clamping produced substantial numbers of small-size particles. These findings emphasize microembolic risks associated with cross-clamping of atherosclerotic vessels.
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| 2. |
- Hedberg, Magnus, 1981-, et al.
(författare)
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Cannulation of the noncalcified aorta generates particles of microembolic nature : an experimental study using pig aorta
- 2008
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Ingår i: Journal of cardiac surgery. - : Hindawi Limited. - 0886-0440 .- 1540-8191. ; 23:1, s. 39-43
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND AND AIM OF THE STUDY: Aortic cannulation during cardiac surgery is a potential etiological factor for perioperative stroke. Cannulae may dislodge aortic-wall calcifications. In addition, the sharp edge of the cannula-tip may shear off vessel-wall tissue, which can be expelled into the lumen. This hypothesis concerning source of emboli was tested in a noncalcified aortic perfusion model. METHODS: Pig aortas were pressurized and cannulated. Washout samples were collected before and after cannulation (n = 40). Particles were deposited onto a 10-microm filter and evaluated by microscopy and digital image analysis. RESULTS: A higher incidence of particles generated by cannulation was noted as compared to before the maneuver (p < 0.001). This increase included small (<0.1 mm, p < 0.001) and intermediate-size particles (0.1-0.5 mm, p < 0.001). Particles above 0.5 mm were few and were not associated with cannulation. CONCLUSIONS: Cannulation was a source of embolic material in the noncalcified aortic model. However, these particles were less than 0.5 mm in diameter and may contribute to neurocognitive decline after cardiac surgery.
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| 3. |
- Hedberg, Magnus, 1981-, et al.
(författare)
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Cerebrovascular accidents after cardiac surgery : an analysis of CT scans in relation to clinical symptoms
- 2005
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Ingår i: Scandinavian Cardiovascular Journal. - : Informa UK Limited. - 1401-7431 .- 1651-2006. ; 39:5, s. 299-305
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Tidskriftsartikel (refereegranskat)abstract
- There is a link between aortic manipulation, particle embolization, and cerebrovascular accidents (CVA) in cardiac surgery. The present aim was to study hemispheric side differences of CVA. Cardiac-surgery patients with CVA and with computer tomography (CT) performed (n = 77) were analyzed within a total group of 2641 consecutive cases. CT data were reviewed for hemispheric and vascular distribution, and compared with CVA-symptom data of immediate and delayed type. Of the included patients, 66% had positive CT. In the group of 'cardiac-type' operations (e.g., routine clamping and cannulation) and having immediate CVA, right-hemispheric lesions were more frequent than of the contra-lateral side (p = 0.005). Patients with aortic dissections had strong dominance of bilateral findings, which was different from the unilateral pattern of 'cardiac-type' operations (p = 0.001). The middle-cerebral artery territory dominated, and when involved showed a significant (p = 0.022) right-sided distribution. Both CT and clinical symptoms confirmed that CVA after cardiac surgery has a right-hemispheric predominance. These observations may imply that aortic manipulation directs embolic material towards the brachiocephalic trunk.
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| 4. |
- Hedberg, Magnus, 1981-, et al.
(författare)
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Early and delayed stroke after coronary surgery : an analysis of risk factors and the impact on short- and long-term survival
- 2011
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Ingår i: European Journal of Cardio-Thoracic Surgery. - : Oxford University Press (OUP). - 1010-7940 .- 1873-734X. ; 40:2, s. 379-387
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Tidskriftsartikel (refereegranskat)abstract
- Objective: Stroke is a serious complication to cardiac surgery, and is generally considered as a uniform disease regardless of its temporal relationship to surgery. Our hypothesis suggests that stroke, in association with surgery, reflects other characteristics than stroke occurring with a free interval. This issue was here explored for risk factors and survival effects. Methods: Data were collected from 7839 procedures of isolated coronary artery bypass grafting (CABG), 297 off-pump CABG, and 986 combined CABG and valve procedures. Records of patients with any signs of neurological complications were reviewed to extract 149 subjects with stroke at extubation (early, 1.6%) versus 99 patients having a free interval (delayed, 1.1%). Survival data were complete, with a median follow-up time of 9.3 years (maximum 16.3 years). Independent risk factors were analyzed by logistic regression and survival by Cox regression. Results: Risk factors for early stroke were advanced age, high preoperative creatinine level, extent of aortic atherosclerosis, and long cardiopulmonary bypass time (all P<0.001). Factors associated with delayed stroke were female gender (P<0.001), unstable angina (P=0.003), previous cerebrovascular disease (P=0.009), inotropic support requirement (P<0.001), and postoperative atrial fibrillation (P<0.001). Stroke explained mortality not only in the early postoperative period (P<0.001), but also at long-term follow-up (P<0.001). Early and delayed stroke were associated with mortality hazard ratios (HRs) of 1.44 and 1.85 (P=0.008, P<0.001), respectively. However, for patients surviving their first postoperative year, early stroke did not influence long-term mortality (HR 1.07, P=0.695). This was in contrast to delayed stroke (HR 1.71, P=0.001). Conclusions: Early and delayed stroke differed in their related risk factors. The influence of stroke on short-term mortality was obvious and devastating. Mortality in association with early stroke mainly presented itself in the acute period, whereas for delayed stroke survival continued to be impaired also in the long-term perspective. Our report emphasizes that early and delayed stroke should be considered as two separate entities.
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| 5. |
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| 6. |
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| 7. |
- Hedberg, Magnus, 1981-
(författare)
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Stroke during cardiac surgery : risk factors, mechanisms and survival effects
- 2010
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Introduction: Neurological complications and stroke in association with cardiac surgery is a serious problem. The stroke event can occur during surgery (early stroke) or in the postoperative period with a symptom free interval (delayed stroke). Particle embolization due to aortic manipulation during surgery has been suspected as a mechanism for early stroke. The present thesis address mechanisms and survival effects of stroke both clinically (I-III) and experimentally (IV-V). Methods: Study I) Within a cohort of 2641 consecutive cases, a group of cardiac surgery patients with stroke and evaluated by computed tomography (CT) were studied (n=77). CT-findings were analyzed in relation to stroke symptoms. Study II) Data from 9122 patients undergoing coronary surgery were analyzed. Records of patients with any signs of neurological complications were reviewed to extract 149 subjects with stroke at extubation (early, 1.6%) versus 99 patients having a free interval (delayed, 1.1%). Early and delayed stroke were evaluated separately. Independent risk factors for stroke were analyzed by logistic regression and survival by Cox regression (9.3 years median follow-up). Study III) Patients with early (n=223) and delayed stroke (n=116) were identified among 10809 patients undergoing cardiac and aortic surgery, both groups exposed to cardiopulmonary bypass. Stroke patients were subdivided by the hemispheric location of lesions. Subgroups were compared and their associated pre- and peroperative variables and survival were analyzed. Study IV) Aortic cross-clamp manipulation was studied in a human cadaveric perfusion model. The pressurized aorta was repeatedly cross-clamped and washout samples were collected before and after clamp maneuvers. Particles in the washout samples were evaluated by microscopy and by digital image analysis. Study V) Pig aortas were pressurized and cannulated. Washout samples were collected before and after cannulation (n = 40). Particles were deposited onto a 10-μm filter to be evaluated by microscopy and digital image analysis. Results: Study I) In the group of patients exposed to routine cardiac surgery (i.e., clamping and cannulation) and with early stroke, right-hemispheric lesions were more frequent than of the contra-lateral side (P=0.005). Patients with aortic dissections had a strong dominance of bilateral findings, which was different from the unilateral pattern in the routine-surgery group (P<0.001). Study II) Early and delayed stroke did not share any risk factors. Both early and delayed stroke explained mortality in the early postoperative period (P<0.001, P<0.001 respectively) but also at long term follow-up (P=0.008, P<0.001 respectively). For patients surviving their first postoperative year, delayed but not early stroke influenced long-term mortality (P=0.001 and P=0.695, respectively). Study III) Stroke lesions in association to cardiac surgery were near exclusively ischemic. Early stroke had a preponderance for right-hemispheric lesions (P=0.009). In contrast, patients with early stroke that had undergone surgery of the aorta with circulatory arrest showed a pattern with more bilateral lesions compared to ‘cardiac-type’ operations (P<0.001). Patients with bilateral lesions had a dramatically impaired survival compared to those with unilateral lesions (P<0.001). Study IV) In the cadaveric perfusion model, cross-clamping produced a significant output of particles, which was seen for size intervals of 1 mm and smaller (P=0.002 to P=0.022). In all size intervals the particle output correlated with the degree of overall aortic calcification (P =0.002 to P=0.025). Study V) At cannulation of the pig aorta, more particles were noted after cannulation compared to before the maneuver (P<0.001). This increase included small (<0.1 mm, P<0.001) and intermediate-size particles (0.1-0.5 mm, P< 0.001). Particles above 0.5 mm were few and were not associated with cannulation. Conclusions: The influence of stroke on mortality was devastating, for both early and delayed stroke. These two stroke groups had obvious differences in both their risk factors and their hemispheric distribution. It is here emphasized that early and delayed stroke should be considered as two separate entities with suggested mechanistic differences. Ischemic lesions accounted for near all stroke events seen in association to cardiac surgery. For early stroke, these were mostly located within the right hemisphere. Results from the experimental studies underscore microembolic risks associated with aortic manipulation.
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| 8. |
- Hosseinpour, Saman, 1981-, et al.
(författare)
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Initial Oxidation of Alkanethiol-Covered Copper Studied by Vibrational Sum Frequency Spectroscopy
- 2011
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Ingår i: The Journal of Physical Chemistry C. - : American Chemical Society (ACS). - 1932-7447 .- 1932-7455. ; 115:48, s. 23871-23879
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Tidskriftsartikel (refereegranskat)abstract
- The oxidation of octadecanethiol (ODT, CH3-(CH2)17SH)-covered copper in dry air has been studied by in situ vibrational sum frequency spectroscopy (VSFS), infrared reflection absorption spectroscopy (IRAS), and cathodic reduction (CR). During the first 10 h of exposure, the VSF spectral line shape in the CH stretching region changed significantly, with resonances observed as dips being transformed into peaks. This was attributed to a phase change in the nonresonant sum frequency signal due to the formation of a thin layer of copper(I) oxide beneath the ODT. Complementary cathodic reduction and infrared reflection/absorption spectroscopy studies yielded a thickness of the oxide layer of <2 nm after 19 h exposure. An orientation analysis on the adsorbed molecules by VSFS indicated a decreased tilt angle of the terminating methyl groups with respect to the surface normal during the formation of the oxide layer.
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| 9. |
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| 10. |
- Linder, Gustav, 1981-
(författare)
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Esophageal- and Gastroesophageal Junctional Cancer : Aspects on Staging, Treatment and Results
- 2018
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Esophageal- and gastroesophageal junctional (GEJ) cancer is the sixth cause of cancer-related death worldwide. Some improvements in care are attributed to nationwide disease-specific registries, preoperative staging and increased understanding of mechanisms affecting patient selection. Surgery, however, is a cornerstone for treatment where minimally invasive surgery and increased understanding of perioperative physiology may be beneficial. The aims of this thesis were to validate the Swedish national registry for esophageal and gastric cancer (NREV) and to explore mechanisms in patient selection, perioperative physiology, treatment-related outcomes and staging.A validation study with re-abstracted data on 400 patients determined NREV comparable to other similar registries and to have a completeness of 95.5 %. Overall accuracy was 91.1 % throughout the registry and timeliness to reporting was adequate.In a cohort of 4112 patients from NREV, high education level was associated with an increased probability of being allocated to curative treatment, as was the presence of a multidisciplinary treatment conference. High education level was associated with improved survival.By measuring intramucosal pH (pHi) in 32 patients, to describe perfusion in the gastric conduit during esophagectomy, a reduction in perfusion was seen at all surgical steps altering vascular supply to the conduit but foremost after gastric tube construction by linear stapling. Patients with low pHi on the first postoperative day were more prone to anastomotic insufficiency.In 116 patients undergoing esophagectomy (65 open and 51 minimally invasive), a retrospective cohort study regarding surgical oncological results and postoperative complications was conducted. Lymph node yield was increased, peroperative blood loss and in-hospital stay were reduced with minimally invasive esophagectomy. Postoperative complications were unaffected by surgical approach. In a prospective study of nineteen patients, whole-body integrated PET/MRI was compared to PET/CT in preoperative staging. PET/MRI was safe and feasible. Accuracy and correlations between modalities were good regarding tumor characteristics and N- and M-staging. In T-staging there were discrepancies indicating differences between modalities.The thesis presents data on the quality of NREV for future research and elaborates on patient selection, staging, perioperative physiology and treatment-related outcomes for patients with esophageal- and GEJ cancer.
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