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Den viktiga rollen för vänster förmaksfunktions parametrar i klinisk praxis
No full textThe aim of this thesis is to evaluate the role of left atrial function in clinical practice based on the following studies: 1) Determining left atrial (LA) structure and myocardial function measurements that predict pulmonary capillary wedge pressure (PCWP). 2) Identifying predictors of exercise capacity in patients with HFpEF and right ventricle (RV) dysfunction. 3) Evaluating the relationship between LA stiffness (LASt) and cardiac events in HF patients with reduced to mid-range ejection fraction. 4) Investigating the relationship between DM and LA remodelling in a group of patients with HF and reduced ejection fraction (HFrEF), and their combined impact on cardiac events. Study I Methods: This is a meta-analysis study. All electronic databases were searched up to December 2018 for studies on the relationship of LA diameter, LA volumes, peak atrial longitudinal strain (PALS), peak atrial contraction strain (PACS) and total emptying fraction (LAEF) with PCWP. Eighteen studies with 1343 patients were included. Summary sensitivity and specificity (with 95% CI) for evaluation of diagnostic accuracy and the best cut-off values for different LA indices in predicting raised PCWP were estimated using summary receiver operating characteristic analysis. Results: The pooled analysis showed association between PCWP and LA diameter: Cohen’s d = 0.87, LAVI max: d = 0.92 and LAVI min: d = 1.0 (p < 0001 for all). A stronger correlation was found between PCWP and PALS: d = 1.26, and PACS: d = 1.62, total EF d = 1.22 (p < 00001 for all). PALS ≤ 19% had a summary sensitivity of 80% (65 - 90) and summary specificity of 77% (52 - 92), and diagnostic odds ratio (DOR) > 15.1, whereas LAVI ≥ 34 ml/m2 had summary sensitivity of 75% (55 - 89) and summary specificity 77% (57 - 90), and DOR > 10.1 in predicting elevated PCWP. Conclusion: Compromised LA myocardial function and increased size predict raised cavity pressure. These results should assist in optimizing the follow-up clinical management of patients with fluctuating LA pressure. Study II Methods: In 143 consecutive patients with HFpEF (age 62 ± 9 years, LV EF ≥45) and 41 controls, a complete echocardiographic study was performed. In addition to conventional measurements, LA compliance was calculated using the formula: [LAV max - LAV min/LAV min × 100]. Exercise capacity was assessed using the six-minute walking test (6-MWT). Tricuspid annular plane systolic excursion (TAPSE) < 1.7 cm was used to categorize patients with RV dysfunction (n = 40) from those with maintained RV function (n = 103). Results: Patients with RV dysfunction were older (p=0.002), had higher NYHA class (p= 0.001), higher LV mass index (p = 0.01), reduced septal and lateral MAPSE (p < 0.001 for all), enlarged LA (p = 0.001) impaired LA compliance index (p < 0.001) and exhibited a more compromised 6-MWT (p = 0.001). LA compliance index correlated more closely with 6-MWT (r = 0.51, p < 0.001) compared with the other LA indices (AP diameter, transverse diameter and volume indexed; r = -0.30, r = -0.35 and r = -0.38, respectively). In multivariate analysis, LA compliance index < 60% was 88% sensitive and 61% specific AUC = 0.80 (CI = 0.67 - 0.92; p = 0.001) in predicting exercise capacity. Conclusion: Impaired LA compliance was profound in patients with HFpEF and RV dysfunction and seems to be the most powerful independent predictor of limited exercise capacity. Study III Methods: This study included 215 consecutive ambulatory heart failure (HF) patients with ejection fraction (EF) < 50% (162 HF reduced EF (HFrEF) and 53 HF mid-range EF HFmrEF)) of mean age 66 ± 11 years and 24.4% were females. Peak LA strain (PALS) was measured by speckle tracking echocardiography and E/e' recorded from the apical four-chamber view. Non-invasive left atrial stiffness (LASt) was calculated using the equation: LASt = E/e' ratio/PALS. Documented cardiac events (CE) were HF hospitalization and cardiac death. Results: During a median follow up of 41 ± 34 months, 65 patients (30%) had CE. In multivariate analysis model, only raised LV filling pressure (E/e'), OR=2.292, (95% CI 2.099 to 2.859; p= 0.02), peak pulmonary artery pressure (PAP), OR = 1.050 (1.009 to 1.094; p= 0.01), PALS (OR = 0.932 (0.873 to 0.994; p = 0.02) and LASt OR = 3.781 (1.144 to 5.122; p = 0.001) independently predicted CE. LASt ≥ 0.76% was the most powerful predictor of CE, with 80% sensitivity, 73% specificity and AUC = 0.82, (CI = 0.73 to 0.87; p < 0.001) followed by PALS ≤ 16%, with 74% sensitivity, 72% specificity and AUC=0.77, (CI = 0.71 to 0.84; p < 0.001). These results were consistent irrespective of EF (p < 0.05). Conclusion: In a cohort of ambulatory HFrEF and HFmrEF patients, left atrial stiffness proved the most powerful predictor of clinical outcome. Study IV Methods. This study included 136 consecutive HFrEF patients (65 ± 11 years), 36 had DM and 86 had increased LA stiffness (LASt). All patients underwent complete conventional and tissue Doppler echocardiographic examinations and measurements were made including LA volumes and function. LASt was calculated using the formula: LASt = E/e’ratio / LA strain. Results. At 55 ± 37 months follow-up, free survival from CE was 69% in patients without DM and 44.4% in those with DM (p < 0.0001). The CE free-survival was lower in patients with increased LASt compared to normal LASt, (50 vs. 80%; p < 0.001), irrespective of the presence of DM (27 vs. 71%, p <0 .001). The best cut-off LASt value for predicting CE in the group as a whole was ≥ 0.82% [81% sensitivity, 72% specificity and AUC 0.82 (p < 0.001)]. LASt ≥ 0.82% also predicted CE in patients without DM [78% sensitivity, 71% specificity and AUC 0.80 (p < 0.001)] and was the strongest predictor in DM patients [85% sensitivity, 71% specificity and AUC = 0.847 (p < 0.001)]. Conclusion. High LA stiffness is associated with poor clinical outcome in patients with heart failure and reduced ejection fraction. Diabetes has an additional incremental value in determining clinical outcome in those patients.Zoom link: https://umu.zoom.us/j/64326354760</p
Stride Length Predicts Adverse Clinical Events in Older Adults : A Systematic Review and Meta-Analysis
No full textBackground: This meta-analysis aims to estimate the power of walking stride length as a predictor of adverse clinical events in older adults. Methods: We searched all electronic databases until April 2021 for studies reporting stride length and other spatial gait parameters, including stride velocity, stride width, step width and stride variability, and compared them with clinical outcomes in the elderly. Meta-analyses of odds ratios (ORs) of effects of stride length on clinical outcomes used the generic inverse variance method and random model effects. Clinical outcomes were major adverse events (MAEs), physical disability and mortality. Results: Eleven cohort studies with 14,167 patients (mean age 75.4 ± 5.6 years, 55.8% female) were included in the analysis. At 33.05 months follow up, 3839 (27%) patients had clinical adverse events. Baseline stride length was shorter, WMD −0.15 (−0.19 to −0.11, p < 0.001), and stride length variability was higher, WMD 0.67 (0.33 to 1.01, p < 0.001), in fallers compared to non-fallers. Other gait parameters were not different between the two groups (p > 0.05 for all). Short stride length predicted MAE OR 1.36 (95% CI; 1.19 to 1.55, p < 0.001), physical disability OR 1.26 (95% CI; 1.11 to 1.44, p = 0.004) and mortality OR 1.69 (95% CI; 1.41 to 2.02, p < 0.001). A baseline normalized stride length ≤ 0.64 m was more accurate in predicting adverse clinical events, with summary sensitivity 65% (58–71%), specificity 72% (69–75%) and accuracy 75.5% (74.2–76.7%) compared to stride length variability 5.7%, with summary sensitivity 66% (61–70%), specificity 56% (54–58%) and accuracy 57.1% (55.5–58.6%). Conclusion: The results of this meta-analyses support the significant value of stride length for predicting life-threatening clinical events in older adults. A short stride length of ≤0.64 m accurately predicted clinical events, over and above other gait measures
High Coronary Wall Shear Stress Worsens Plaque Vulnerability : A Systematic Review and Meta-Analysis
No full textAim: The aim of this meta-analysis is to assess the impact of wall shear stress (WSS) severity on arterial plaque vulnerability. Methods: We systematically searched electronic databases and selected studies which assessed the relationship between WSS measured by intravascular ultrasound and coronary artery plaque features. In 7 studies, a total of 615 patients with 28 276 arterial segments (median follow-up: 7.71 months) were identified. At follow-up, the pooled analysis showed high WSS to be associated with regression of plaque fibrous area, weighted mean difference (WMD) −0.11 (95% CI: −0.20 to −0.02, P = .02) and fibrofatty area, WMD −0.09 (95% CI: −0.17 to −0.01, P = .02), reduction in plaque total area, WMD −0.09 (95% CI: −0.14 to −0.04, P = .007) and increased necrotic core area, and WMD 0.04 (95% CI: 0.01-0.09, P = .03) compared with low WSS. Dense calcium deposits remained unchanged in high and low WSS (0.01 vs 0.02 mm2; P > .05). High WSS resulted in profound remodeling (40% vs 18%, P < .05) and with more constructive remodeling than low WSS (78% vs 40%, P < .01). Conclusions: High WSS in coronary arteries is associated with worsening plaque vulnerability and more profound arterial wall remodeling compared with low WSS
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Left atrial volume index predicts response to cardiac resynchronisation therapy : a systematic review and meta-analysis
No full textIntroduction: In responders, cardiac resynchronisation therapy (CRT) results in improved left ventricular (LV) function and reduced atrial arrhythmia. The aim of this meta-analysis was to assess the potential relationship between the left atrium (LA) volume and CRT response. Material and methods: We systematically searched all electronic databases up to August 2018 in order to select clinical trials and observational studies that assessed the predictive value of LA volume index (LAVI) of CRT response. Left ventricular end-systolic volume (LVESV) reduction ≥ 15 ml and/ or LV ejection fraction (EF) increase ≥ 10% were the documented criteria for positive CRT response. Results: A total of 2191 patients recruited in 10 studies with mean follow-up duration of 10.5 months were included in this meta-analysis. The pooled analysis showed that CRT responders had lower baseline LAVI compared to non-responders, with a weighted mean difference (WMD) of -5.89% (95% CI: -9.47 to -3.22, p < 0.001). At follow-up, LAVI fell in the CRT responders (WMD -4.36%, 95% CI: -3.54 to -5.17, p < 0.001) compared to non-responders (WMD 1.45 %, 95% CI: -0.75 to 3.65, p = 0.20). The mean change of LAVI in the CRT responders was related to the fall in LVESV, β = -1.02 (-1.46 to -0.58), p < 0.001 and the increase in LVEF, β = 2.02 (1.86 to 4.58), p = 0.001. A baseline LAVI < 34 ml/m2 predicted CRT response with summary sensitivity 0.80% (0.53-0.95), specificity 0.74% (0.53-0.89), and odds ratio > 11. Conclusions: Baseline LAVI predicts CRT response, and its reduction reflects devise-related LA remodelling. These results emphasis the role of LAVI assessment as an integral part of cardiac function response to CRT
Left atrial strain increases in CRT responders : a systematic review and meta-analysis
No full textBackground and aim: Impaired left atrial (LA) strain is associated with myocardial fibrosis and carries poor prognosis, especially arrhythmia. Cardiac resynchronization therapy (CRT) is associated with reserved LA remodeling and reduced arrhythmia. The aim of this meta-analysis was to assess the relationship between CRT and LA function improvement.Methods: We systematically searched PubMed-Medline, EMBASE, Scopus, Google Scholar and the Cochrane Central Registry, up to February 2018 in order to select clinical trials and observational studies, which assessed the predictive value of LA strain of CRT response. The left ventricular end-systolic volume (LVESV) reduction ≥15 ml and/or LV ejection fraction (EF) increase ≥10% were the documented criteria for assessment of CRT response.Results: A total of 299 patients (181 responders and 118 non-responders to CRT) from 5 observational studies, with mean follow-up period of 6 months were included in this meta-analysis. The pooled analysis showed no difference between baseline LA strain in the two groups with weighted mean difference (WMD) 1.07% [95% CI -2.37 to 4.51, P=0.54, Figure 1]. After the follow-up period, LA strain in the CRT responders significantly increased, WMD 27.7% [95% CI 23.1 to 32.6, P<0.001, Figure 2, a)], but not in the non-responders, WMD -34.5 [95% CI -38.4 to -30.6, p<0.001, Figure 2, b)].Conclusions: Improvement of LA strain in CRT responders reflects LA reserve remodeling. These results support the importance of LA function in patients treated by CRT for heart failure.</p
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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