Vasoplegia after implantation of a continuous flow left ventricular assist device: incidence,outcomes and predictors

Background

Vasoplegia after routine cardiac surgery is associated with severe postoperative complications and increased mortality. It is also prevalent in patients undergoing implantation of pulsatile flow left ventricular assist devices (LVAD). However, less is known regarding vasoplegia after implantation of newer generations of continuous flow LVADs (cfLVAD). We aim to report the incidence, impact on outcome and predictors of vasoplegia in these patients.

Methods

Adult patients scheduled for primary cfLVAD implantation were enrolled into a derivation cohort (n?=?118, 2006–2013) and a temporal validation cohort (n?=?73, 2014–2016). Vasoplegia was defined taking into consideration low mean arterial pressure and/or low systemic vascular resistance, preserved cardiac index and high vasopressor support. Vasoplegia was considered after bypass and the first 48?h of ICU stay lasting at least three consecutive hours. This concept of vasoplegia was compared to older definitions reported in the literature in terms of the incidence of postoperative vasoplegia and its association with adverse outcomes. Logistic regression was used to identify independent predictors. Their ability to discriminate patients with vasoplegia was quantified by the area under the receiver operating characteristic curve (AUC).

Results

The incidence of vasoplegia was 33.1% using the unified definition of vasoplegia. Vasoplegia was associated with increased ICU length-of-stay (10.5 [6.9–20.8] vs 6.1 [4.6–10.4] p?=?0.002), increased ICU-mortality (OR 5.8, 95% CI 1.9–18.2) and one-year-mortality (OR 3.9, 95% CI 1.5–10.2), and a higher incidence of renal failure (OR 4.3, 95% CI 1.8–10.4). Multivariable analysis identified previous cardiothoracic surgery, preoperative dopamine administration, preoperative bilirubin levels and preoperative creatinine clearance as independent preoperative predictors of vasoplegia. The resultant prediction model exhibited a good discriminative ability (AUC 0.80, 95% CI 0.71–0.89, p?<? 0.01). Temporal validation resulted in an AUC of 0.74 (95% CI 0.61–0.87, p?<? 0.01).

Conclusions

In the era of the new generation of cfLVADs, vasoplegia remains a prevalent (33%) and critical condition with worse short-term outcomes and survival. We identified previous cardiothoracic surgery, preoperative treatment with dopamine, preoperative bilirubin levels and preoperative creatinine clearance as independent predictors.

     

Disentangling vegetation and climate as drivers of Australian vertebrate richness

Determining drivers of species richness is recognised as highly complex, involving many synergies and interactions. We examine the utility of newly available remote sensing representations of vegetation productivity and vegetation structure to examine drivers of species richness at continental and regional scales. We related richness estimates derived from stacked species distribution models for birds, mammals, amphibians, and reptiles to estimates of actual and potential evapotranspiration (AET and PET), forest structure, and forest productivity across Australia as a whole as well as by bioclimatic zones. We used structural equation modeling to partition correlations between climate energy and vegetation attributes and their subsequent associations with species richness. Continentally, vertebrate richness patterns were strongly related to patterns of energy availability. Richness of amphibians, mammals, and birds were positively associated with AET. However, reptile richness was most strongly associated with PET. Regionally, forest structure and productivity associations with bird, mammal, and amphibian richness were strongest. Again, reptile richness associated most strongly with PET. Our results suggest that a hierarchy of drivers of broad‐scale vertebrate richness patterns exist (reptiles excluded): 1) climate energy is most important at the continental scale; next, 2) vegetation productivity and vegetation structure are most important at the regional scale; except 3) at low extremes of climate energy when energy becomes limiting.     

Shellfish Reefs Increase Water Storage Capacity on Intertidal Flats Over Extensive Spatial Scales

Ecosystem engineering species can affect their environment at multiple spatial scales, from the local scale up to a significant distance, by indirectly affecting the surrounding habitats. Structural changes in the landscape can have important consequences for ecosystem functioning, for example, by increasing retention of limiting resources in the system. Yet, it remains poorly understood how extensive the footprint of ecosystem engineers on the landscape is. Using remote sensing techniques, we reveal that depression storage capacity on intertidal flats is greatly enhanced by engineering by shellfish resulting in intertidal pools. Many organisms use such pools to bridge low water events. This storage capacity was significantly higher both locally within the shellfish reef, but also at extensive spatial scales up to 115 m beyond the physical reef borders. Therefore, the footprint of these ecosystem engineers on the landscape was more than 5 times larger than their actual coverage; the shellfish cover approximately 2% of the total intertidal zone, whereas they influence up to approximately 11% of the area by enhancing water storage capacity. We postulate that increased residence time of water due to higher water storage capacity within engineered landscapes is an important determinant of ecosystem functioning that may extend well beyond the case of shellfish reefs provided here.     

Human plasma protein <Emphasis Type="Italic">N</Emphasis>-glycosylation

Glycosylation is the most abundant and complex protein modification, and can have a profound structural and functional effect on the conjugate. The oligosaccharide fraction is recognized to be involved in multiple biological processes, and to affect proteins physical properties, and has consequentially been labeled a critical quality attribute of biopharmaceuticals. Additionally, due to recent advances in analytical methods and analysis software, glycosylation is targeted in the search for disease biomarkers for early diagnosis and patient stratification. Biofluids such as saliva, serum or plasma are of great use in this regard, as they are easily accessible and can provide relevant glycosylation information. Thus, as the assessment of protein glycosylation is becoming a major element in clinical and biopharmaceutical research, this review aims to convey the current state of knowledge on the N-glycosylation of the major plasma glycoproteins alpha-1-acid glycoprotein, alpha-1-antitrypsin, alpha-1B-glycoprotein, alpha-2-HS-glycoprotein, alpha-2-macroglobulin, antithrombin-III, apolipoprotein B-100, apolipoprotein D, apolipoprotein F, beta-2-glycoprotein 1, ceruloplasmin, fibrinogen, immunoglobulin (Ig) A, IgG, IgM, haptoglobin, hemopexin, histidine-rich glycoprotein, kininogen-1, serotransferrin, vitronectin, and zinc-alpha-2-glycoprotein. In addition, the less abundant immunoglobulins D and E are included because of their major relevance in immunology and biopharmaceutical research. Where available, the glycosylation is described in a site-specific manner. In the discussion, we put the glycosylation of individual proteins into perspective and speculate how the individual proteins may contribute to a total plasma N-glycosylation profile determined at the released glycan level.     

High-resolution, human–bovine comparative mapping based on a closed YAC contig spanning the bovine mh locus

A closed YAC contig spanning the mh locus was assembled by STS content mapping with seven microsatellite markers, eight genes or EST, and nine STS corresponding to YAC ends. The contig comprises 27 YACs, has an average depth of 4.3 YACs, and spans an estimated 1.2 Mb. A linkage map was constructed based on five of the microsatellite markers anchored to the contig and shown to span 7 cM, yielding a ratio of 160 kb/1 cM for the corresponding chromosome region. Comparative mapping data indicate that the constructed contig spans an evolutionary breakpoint connecting two chromosome segments that are syntenic but not adjacent in the human. Consolidation of human gene order by means of whole genome radiation hybrids and its comparison with the bovine order as inferred from the contig confirm conservation of gene order within segments. Received: 6 August 1998 / Accepted: 28 October 1998