Venous thromboembolism and obstruction after pacemaker implantation. - A Prospective Study of 150 Consecutive Cardiac Pacing Device Implantations

Background: Pacemaker implantation (PMI) may predispose to venous thromboembolism (VTE) and obstruction (VO). This prospective study aimed at quantifying changes in venous calibers, and at determining the incidence of symptomatic and asymptomatic VTE/VO after PMI. Further goals included an assessment of the role of transesophageal echocardiography (TEE) in the diagnosis of lead-related central venous thrombi (CVT), and determination of predictors for VTE/VO. Methods: 150 (mean age 67; 61% male) consecutive patients with first PMI were enrolled and followed for 6 months. Contrast venography was performed at baseline and 6 months after PMI to measure venous diameters, and to detect stenosis, total occlusions and thrombi. TEE was conducted in 66 patients. Based on clinical suspicion, work-up for pulmonary embolism (PE) or acute deep vein thrombosis (DVT) were performed as needed. A total of 50 cases underwent longer-term (mean 2.4 years) follow-up venography. All cases with VTE/VO during the initial 6 months, and their matched controls, were selected for a case-control study focused on possible predictive role of laboratory and patient-related factors for the development of VTE/VO. Results: 10 (7 %) patients were found to have baseline venous abnormalities (e.g. 8 obstructions). Mean venous diameters diminished significantly during the first 6 months, but no further reduction occurred in late follow-up. New VO was discovered in 19 patients (14 %; 14 stenosis, 5 total occlusions; all asymptomatic). Small non-obstructive thrombi were found in 20/140 (14 %) 6-month venograms. TEE at 6 months disclosed CVT in 6 (9 %) patients. One (0.7 %) patient had acute symptomatic upper-extremity DVT, and PE was discovered in 5/150 (3.3 %) patients during the first 6 months with no further cases thereafter. At 6 months, the total number of cases with VTE/VO amounted to 47 (31.3 %). Additionally, the later 2-year venograms (n=50) disclosed 4 (8 %) total occlusions and 1 (2 %) stenosis. In the case-control study, no parameter was predictive of venous end-points as a single variable, but there appeared to be significant clustering of traditional VTE risk-factors among the cases. Laboratory parameters showed a definite acute hypercoagulative state induced by PMI, but its degree did not predict subsequent development of VTE/VO. Conclusions: This study shows that VTE/VO is relatively common after PMI with an overall incidence of at least 30 %. Although the majority of the lesions are asymptomatic and clinically benign, cases of PE were also encountered, and totally occluded veins may hamper future upgrading or replacement of pacing system. Venous complications seem difficult to prognosticate as firm predictors were not identified from a wide range of parameters analyzed in this study, although clustering of classic VTE risk factors may be a predisposing factor. Parameters related to implantation procedure or pacing systems and the severity of implantation-induced trauma did not emerge as predictors.

Recording and reproducing Soundscapes : using and interpreting data in a creative way

http://elo.aalto.fi/fi/studies/elomedia/dataseminar/

Interpreting marine benthic ecosystem functioning in coastal waters: validating the biological trait concept

Coastal areas harbour high biodiversity, but are simultaneously affected by rapid degradations of species and habitats due to human interactions. Such alterations also affect the functioning of the ecosystem, which is primarily governed by the characteristics or traits expressed by the organisms present. Marine benthic fauna is nvolved in numerous functions such as organic matter transformation and transport, secondary production, oxygen transport as well as nutrient cycling. Approaches utilising the variety of faunal traits to assess benthic community functioning have rapidly increased and shown the need for further development of the concept. In this thesis, I applied biological trait analysis that allows for assessments of a multitude of categorical traits and thus evaluation of multiple functional aspects simultaneously. I determined the functional trait structure, diversity and variability of coastal zoobenthic communities in the Baltic Sea. The measures were related to recruitment processes, habitat heterogeneity, large-scale environmental and taxonomic gradients as well as anthropogenic impacts. The studies comprised spatial scales from metres to thousands of kilometres, and temporal scales spanning one season as well as a decade. The benthic functional structure was found to vary within and between seagrass landscape microhabitats and four different habitats within a coastal bay, in papers I and II respectively. Expressions of trait categories varied within habitats, while the density of individuals was found to drive the functional differences between habitats. The findings in paper III unveiled high trait richness of Finnish coastal benthos (25 traits and 102 cateogries) although this differed between areas high and low in salinity and human pressure. In paper IV, the natural reduction in taxonomic richness across the Baltic Sea led to an overall reduction in function. However, functional richness in terms of number of trait categories remained comparatively high at low taxon richness. Changes in number of taxa within trait categories were also subtle and some individual categories were maintained or even increased. The temporal analysis in papers I and III highlighted generalities in trait expressions and dominant trait categories in a seagrass landscape as well as a “type organism” for the northern Baltic Sea. Some initial findings were made in all four papers on the role of common and rare species and traits for benthic community functioning. The findings show that common and rare species may not always express the same trait categories in relation to each other. Rare species in general did not express unique functional properties. In order to advance the understanding of the approach, I also assessed some issues concerning the limitations of the concept. This was conducted by evaluating the link between trait category and taxonomic richness using especially univariate measures. My results also show the need to collaborate nationally and internationally on safeguarding the utility of taxonomic and trait data. The findings also highlight the importance of including functional trait information into current efforts in marine spatial planning and biomonitoring.