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Abstract Aims Increasing numbers of patients with advanced heart failure and significant comorbidity and social barriers are considered for left ventricular assist devices (LVADs). We sought to examine health care utilization post‐LVAD implantation, including the influence of individual‐level socio‐economic position and multimorbidity. Methods and results We conducted a Danish nationwide cohort study linking individual‐level data from clinical LVAD databases, the Scandiatransplant Database, and Danish national medical and administrative registries. Socio‐economic position included cohabitation status, educational level, and employment status. Multimorbidity was defined as two or more chronic conditions from at least two chronic disease groups. Health care utilization (hospital activity, general practice activity, and redeemed medical prescriptions) within 2 years post‐discharge after LVAD implantation was evaluated using descriptive statistics at 0.5 year intervals. We identified 119 patients discharged alive with first‐time LVAD implanted between 2006 and 2018. The median age of the patients was 56.1 years, and 88.2% were male. Patients were followed until heart transplantation, LVAD explantation, death, 31 December 2018, or for 2 years. The median follow‐up was 0.8 years. The highest median use of health care services was observed 0–0.5 years post‐LVAD discharge compared with the subsequent follow‐up intervals: 0.5–1, 1–1.5, and 1.5–2 years, respectively. The median (interquartile range) number of hospitalizations was 10 (7–14), bed days 14 (9–28), outpatient visits 8 (5–12), telephone contacts with a general practitioner 4 (2–8), and total redeemed medical prescriptions 26 (19–37) within 0–0.5 years post‐LVAD discharge compared with the median utilization within the consecutive follow‐up periods [e.g. within 0.5–1 year: hospitalizations 5 (3–8), bed days 8 (4–14), outpatient visits 5 (3–8), telephone contacts 2 (0–5), and redeemed medical prescriptions 24 (18–30)]. The median use of health care services was stable from 0.5 years onwards. The median number of hospitalizations and bed days was slightly higher in patients living alone with a low educational level or low employment status within 0–0.5 years post‐LVAD implantation. Finally, the median number of in‐hospital days and redeemed prescriptions was higher among patients with pre‐existing multimorbidity. Conclusions Among patients who underwent LVAD implantation, health care utilization was high in the early post‐LVAD discharge phase and was influenced by socio‐economic position. Multimorbidity influenced the number of in‐hospital days and redeemed prescriptions during the 2 year follow‐up.

Abstract Background Endotheliopathy is suggested as pivotal pathophysiology of sepsis and trauma-associated organ failure, but its role in acute respiratory failure is not yet determined. We investigated if endotheliopathy biomarkers at ICU admission are associated with illness severity and clinical outcomes in patients with acute respiratory failure requiring mechanical ventilation. Methods We conducted a prospective single-center cohort study including 459 mechanically ventilated adults at ICU admission. Plasma levels of three endotheliopathy biomarkers were measured at ICU admission: Syndecan-1, soluble Thrombomodulin (sTM), and Platelet Endothelial Cell Adhesion Molecule-1 (PECAM-1). The primary outcome was the rate of liberation from mechanical ventilation, which is presented together with the rate of the competing risk of death while still on mechanical ventilation. Secondary outcomes were PaO2/FiO2-ratios on admission and on last measurement in patients dying within five days, and 30-day all-cause mortality. The primary outcome and 30-day all-cause mortality were analyzed using Cox regression, controlled for gender, age, chronic obstructive pulmonary disease, septic shock, heart failure, PaO2/FiO2-ratio at admission, respiratory infection, acute kidney injury, and bilirubin. PaO2/FiO2-ratios were analyzed using linear regression, controlled for age, chronic obstructive pulmonary disease, respiratory infection, and shock. Results Patients with high sTM were liberated from mechanical ventilation at a lower rate (adjusted hazard ratio (HR) 0.71, for an increase from the 25th to the 75th percentile, 95% confidence interval (CI) 0.54–0.93, p = 0.01). Patients with high PECAM-1 were liberated from mechanical ventilation at a lower rate, but only during the first 5 days (adjusted HR 0.72, for an increase from the 25th to the 75th percentile, 95% CI 0.58–0.9, p

Voltage-gated potassium channels of the KV7 family are expressed in many tissues. The physiological importance of KV7 channels is evident from specific forms of disorders linked to dysfunctional KV7 channels, including variants of epilepsy, cardiac arrhythmia and hearing impairment. Thus, understanding how KV7 channels are regulated in the body is of great interest. This Mini Review focuses on the effects of polyunsaturated fatty acids (PUFAs) on KV7 channel activity and possible underlying mechanisms of action. By summarizing reported effects of PUFAs on KV7 channels and native KV7-mediated currents, we conclude that the generally observed effect is a PUFA-induced increase in current amplitude. The increase in current is commonly associated with a shift in the voltage-dependence of channel opening and in some cases with increased maximum conductance. Auxiliary KCNE subunits, which associate with KV7 channels in certain tissues, may influence PUFA effects, though findings are conflicting. Both direct and indirect activating PUFA effects have been described, direct effects having been most extensively studied on KV7.1. The negative charge of the PUFA head-group has been identified as critical for electrostatic interaction with conserved positively charged amino acids in transmembrane segments 4 and 6. Additionally, the localization of double bonds in the PUFA tail tunes the apparent affinity of PUFAs to KV7.1. Indirect effects include those mediated by PUFA metabolites. Indirect inhibitory effects involve KV7 channel degradation and re-distribution from lipid rafts. Understanding how PUFAs regulate KV7 channels may provide insight into physiological regulation of KV7 channels and bring forth new therapeutic strategies.

The voltage-gated potassium channel KV7.1 and the auxiliary subunit KCNE1 together form the cardiac IKs channel, which is a proposed target for future anti-arrhythmic drugs. We previously showed that polyunsaturated fatty acids (PUFAs) activate KV7.1 via an electrostatic mechanism. The activating effect was abolished when KV7.1 was co-expressed with KCNE1, as KCNE1 renders PUFAs ineffective by promoting PUFA protonation. PUFA protonation reduces the potential of PUFAs as anti-arrhythmic compounds. It is unknown how KCNE1 promotes PUFA protonation. Here, we found that neutralization of negatively charged residues in the S5-P-helix loop of KV7.1 restored PUFA effects on KV7.1 co-expressed with KCNE1 in Xenopus oocytes. We propose that KCNE1 moves the S5-P-helix loop of KV7.1 towards the PUFA-binding site, which indirectly causes PUFA protonation, thereby reducing the effect of PUFAs on KV7.1. This mechanistic understanding of how KCNE1 alters KV7.1 pharmacology is essential for development of drugs targeting the IKs channel.

About 300 loss-of-function mutations in the IKs channel have been identified in patients with Long QT syndrome and cardiac arrhythmia. How specific mutations cause arrhythmia is largely unknown and there are no approved IKs channel activators for treatment of these arrhythmias. We find that several Long QT syndrome-associated IKs channel mutations shift channel voltage dependence and accelerate channel closing. Voltage-clamp fluorometry experiments and kinetic modeling suggest that similar mutation-induced alterations in IKs channel currents may be caused by different molecular mechanisms. Finally, we find that the fatty acid analogue N-arachidonoyl taurine restores channel gating of many different mutant channels, even though the mutations are in different domains of the IKs channel and affect the channel by different molecular mechanisms. N-arachidonoyl taurine is therefore an interesting prototype compound that may inspire development of future IKs channel activators to treat Long QT syndrome caused by diverse IKs channel mutations.