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- Eriksson, Marie, 1970-
(författare)
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Aspects on stroke outcome : survival, functional status, depression and sex differences in Riks-Stroke, the National Quality Register for Stroke Care
- 2008
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Stroke is a major cause of death and disability worldwide. In Sweden, about 30 000 strokes occur each year. The aim of this thesis was to analyse survival, functional outcome and self-reported depression after stroke, and to explore possible differences between men and women in stroke care and outcome. These studies were based on Riks-Stroke, the Swedish national quality register for stroke care. Information on background variables and treatment were collected during the hospital stay. The patient’s situation and outcome after stroke were followed-up after 3 months. Long term survival was retrieved from the Swedish Population Register (Folkbokföringen). Possible sex-differences in stroke care and outcome 3 months after stroke were explored in 24 633 strokes, registered during 2006. In conscious patients, the proportions treated at stroke units were similar for men and women. Men and women had equal chance to receive thrombolytic therapy or secondary prevention with oral anticoagulants. Compared to men, women were less likely to develop pneumonia, but more likely to experience deep venous thromboses and fractures during hospital stay. Women had worse 3-month survival and functional outcome, differences that were explained by their higher age and impaired level of consciousness on admission. Women felt more depressed and perceived their health as worse than men did. Women were also less satisfied with the care they had received in the hospital. The agreement between self-reported functional outcome 3 months after stroke and the commonly used modified Rankin Scale (mRS) was explored in 555 stroke survivors from 4 hospitals during May-September 2005. Riks-Stroke’s self-reported questions classified 76% of the patients into correct mRS grade. The association between functional outcome 3 months after stroke and 3-year survival was assessed in 15 959 men and women who had had a stroke during 2001-2002. Patients with estimated mRS grades 3, 4 and 5 had hazard ratios for death of 1.7, 2.5 and 3.8, respectively, as compared with patients with lower grades, 0-2. Depressed mood, male sex, high age, diabetes, smoking, antihypertensive therapy at onset and atrial fibrillation were also identified as predictors of poor survival. Self-reported depression 3 months after stroke and use of antidepressants were analysed in 15 747 stroke survivors from 2002. Fourteen percent felt depressed 3 months after stroke. Female sex, age <65, previous stroke, living alone or in institution, or being dependent in activities of daily living (ADL) were factors associated with self-reported depression. At the follow-up, 22% of the men and 28% of the women were using antidepressant medication, which were approximately twice as many as in the general population. Still, 8% of all patients in Riks-Stroke reported depressive mood but no treatment with antidepressants. In conclusion, men and women with stroke in Sweden experience similar treatment and outcome in most aspects. Patient-reported functional outcome can be reliably transformed to a standard disability scale. Impaired functional outcome three months after stroke is an independent predictor of poor long-term survival. Depressive mood is common after stroke and is associated with poor survival and impaired functional outcome.
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| 4. |
- Skagerlind, Malin, 1975-
(författare)
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How to reduce the exposure to anticoagulants when performing haemodialysis in patients with a bleeding risk : a study of methods used in clinical practise
- 2017
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- When a patient suffers from kidney failure and also has an enhanced risk of bleeding, the standard haemodialysis (HD) treatment becomes a problem. When human blood comes in contact with artificial material, as in the tubing system and in the dialyser (the extra corporeal circuit, ECC), the coagulation system is activated. If there is no increased risk of bleeding a bolus dose of anticoagulation is given intravenous to the patient before HD to avoid clotting. The most common anticoagulants used during HD are unfractionated heparin (UFH) and low molecule weight heparins (LMWH). Without anticoagulants there will be a total coagulation (clotting) of the blood in the ECC, an interrupted treatment and a blood loss of up to 300 ml for the patient. With an ongoing bleeding or an increased risk of bleeding in a patient that also needs HD, there are various alternatives that can be used to avoid or lower the need of anticoagulation. However, there is no golden standard, neither in Sweden or worldwide.The overall aim of this Thesis was to evaluate the safety and the efficacy of various models of anticoagulation that may be used in patients with a bleeding risk.The first study examined a low-dose anticoagulation model that was locally developed in Umeå, Sweden in the 1980s. The primary aim was to clarify to what extent this priming model was safe and efficient during intermittent HD for patients with a bleeding risk. Consecutive acute HD treatment protocols (248 procedures in 68 patients) were included. There were 178 patients with an increased bleeding risk who had their ECC (tubes, chambers and dialyser) flushed through (priming) with Heparin-Albumin-priming (HA-priming). There were 70 patients with no increased bleeding risk who received standard intermittent HD (priming with saline); these patients also received a bolus dose of anticoagulation intravenous before dialysis.The low-dose method entailed priming of the ECC with HA-priming with the intention to coat the surfaces with the solution and protect from blood to attach to it. Comparisons were made to dialysis in patients with no increased bleeding risk, who had received standard anticoagulation (SHD) with UFH or LMWH. The priming solutions were always discarded before HD was initiated. None or limited doses of UFH were added during the HD. There was no difference in extent of prematurely interrupted HA-primed dialysis compared to SHD (2.2 vs. 4.3%, p = 0.62). No secondary bleeding due to anticoagulation was reported in the protocols.Study 2 was performed to further clarify data in an extended group of acute intermittent HD using either HA-priming (885 treatments in 221 patients at risk of bleeding) or SHD (523 treatments in 100 patients with no bleeding risk who had received standard anticoagulation). In this extended study there was no difference in the extent of prematurely interrupted HA-dialysis (0.8%) compared to SHD (1%, p = 0.8). The results also showed less clotting for dialysers with a membrane area ≤ 1.7 m2. No secondary bleeding due to anticoagulation was reported in the protocols.Study 3 was an experimental in vitro study. The aim was to compare the anticoagulation effect of priming the ECC with different concentrations of albumin and/or heparin in saline. Priming with saline only was also evaluated. The priming fluids were always discarded after priming. Fresh whole blood from healthy human donors was used to perform in vitro dialyses in a recirculation system. The donated blood was equally divided into two bags, whereas one bag represented the control group and the other the intervention group. Priming with saline only and priming with albumin in saline resulted in rapid clotting of the blood in the ECC. These experiments indicated that HA-priming or priming with heparin in saline enabled fulfilment of all the in vitro dialyses.Study 4 was a clinical randomized cross-over study. The aim was to minimize the use of anticoagulant during HD in patients with a bleeding risk. Four different low-dose anticoagulation models were compared to SHD. Stable chronic HD patients participated in the study. The patients were their own controls. Aside from SHD, the four models of low-dose anticoagulation used were Heparin priming (H), HA-priming (HA), HA-priming in combination with a citrate containing dialysate (HAC), and a dialyser manufactured with a heparin-grafted membrane (Evodial®). The H-model was least suitable with 33 % interrupted treatments and the most extra doses of UFH needed. The HAC and Evodial® models were most preferable, both with an activated partial thromboplastin time (APTT) within references and with the least amounts of UFH needed. Evodial® had a lower urea reduction rate compared to the other models. HAC was the only model with no interrupted treatment. One patient suffered from a severe hypersensitivity reaction using Evodial®. No other side-effects were reported during the study.In conclusion an acute kidney injury is a life-threating situation that also includes patients with an increased bleeding risk and in need of HD for survival. If intermittent HD is the selected option, a priming of the ECC with a HA-solution in combination with a citrate containing dialysis fluid (HAC) is a safe and sufficient option for anticoagulation. Another option could be the heparin-grafted dialyser (Evodial®), although with a lower clearance coefficient and with a caution for a risk for hypersensitivity reaction or anaphylaxis.
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- Wiklund, Per-Gunnar, 1963-
(författare)
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Genetic aspects of stroke : association and linkage studies in a northern Swedish population
- 2005
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Stroke is a common, multifactorial cardiovascular disease. A stroke event is the result of traditional risk factors (i.e. hypertension, diabetes, smoking), environmental exposures and genetic factors in a complex interplay. The genetic contribution is, as estimated by studies on the influence of family history on the risk of stroke, limited on the individual level, and overridden by, for example the excess risk associated with smoking. On the population level, and as a means to better understand the etiology of stroke, genetics can play a major role.Northern Sweden is well suited for studying the genetic aspects of stroke. The population shows signs of founder effects, and is relatively homogeneous. Large-scale cardiovascular health surveys, the MONICA Project and the Västerbotten Intervention Program, allow studies on risk factors in relation to stroke. Two prospective nested case-referent study samples, (113 cases and 226 controls; 275 cases and 549 controls), and a set of 56 families (117 affected) were collected for functional candidate gene association, and linkage, studies.The selected candidate genes included haemostatic factors and genes within the renin angiotensin system (RAS). Functional single nucleotide polymorphisms (SNPs) that influence the levels of PAI-1 (PAI-1 4G/5G), and tPA (tPA -7,351C>T), have been identified. The angiotensin converting enzyme insertion/deletion polymorphism (ACE I/D) has been shown to be associated with ischaemic stroke. The angiotensin II receptor type 1 A1166C polymorphism (AT1R A1166C), less extensively studied, has been suggested to be associated with stroke, and to interact with the ACE I/D.We found that the PAI-1 4G/4G genotype was associated with an increased risk of future ischaemic stroke (OR 1.79, 95%CI 1.01-3.19), and this was replicated in a second study sample. Furthermore, levels of serum triglycerides modulated the effect of the genotype. In the study on tPA, no association between the tPA -7,351C>T polymorphism and the risk of stroke was found in an analysis of the two study samples pooled. The two RAS polymorphisms were prospectively associated with ischaemic stroke independently of each other and other risk factors (OR 1.60, p=0.02 and OR 1.60, p=0.04, respectively).A candidate region linkage study, focusing on a previously reported stroke susceptibility locus on chromosome 5, was performed in a set of families. In addition, association between ischemic stroke and the positional candidate gene phosphodiesterase 4D (PDE4D) was tested. Linkage to 5q12 was replicated in this independent population, but not PDE4D association with stroke. This suggests that alternative genotypes in this stroke susceptibility locus contribute in different populations.In conclusion, the genetic component in the causation of stroke was investigated. The results of the functional candidate gene association studies showed (1) interaction between PAI-1 genotype and a putatively modifiable risk factor, triglycerides, (2) a prospective testing of the tPA SNP with no association detected, and (3) a novel, hypothesis-generating, finding in the case of AT1R polymorphism and the risk of ischaemic stroke. The replication of linkage to chromosome 5q12 in our northern Swedish population was interesting, and it will be further explored.
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