Heparin Dosing Regimen Optimization in Veno-Arterial Extracorporeal Membrane Oxygenation: A Pharmacokinetic Analysis

Background. Unfractionated heparin is administered in patients undergoing veno-arterial extracorporeal membrane oxygenation (VA-ECMO). Anticoagulation monitoring is recommended, with an anti-activated factor X (anti-Xa) targeting 0.3 to 0.7 IU/mL. Owing to heparin’s heterogeneous pharmacokinetic properties, anti-Xa is unpredictable, generating a challenge in anticoagulation practices. The aim of this study was to build a pharmacokinetic model of heparin accounting for potential confounders, and derive an optimized dosing regimen for a given anti-Xa target. Methods. Adult patients undergoing VA-ECMO were included between January 2020 and June 2021. Anticoagulation was managed with an initial 100 IU/kg heparin loading dose followed by a continuous infusion targeting 0.2 to 0.7 IU/mL anti-Xa. The data were split into model development and model validation cohorts. Statistical analysis was performed using a nonlinear mixed effects modeling population approach. Model-based simulations were performed to develop an optimized dosing regimen targeting the desired anti-Xa. Results. A total of 74 patients were included, with 1703 anti-Xa observations. A single-compartment model best fitted the data. Interpatient variability for distribution volume was best explained by body weight, C-reactive protein and ECMO indication (post-cardiotomy shock or medical cardiogenic shock), and interpatient variability for elimination clearance was best explained by serum creatinine and C-reactive protein. Simulations using the optimized regimen according to these covariates showed accurate anti-Xa target attainment. Conclusion. In adult patients on VA-ECMO, heparin’s effect increased with serum creatinine and medical indication, whereas it decreased with body weight and systemic inflammation. We propose an optimized dosing regimen accounting for key covariates, capable of accurately predicting a given anti-Xa target

Association between pulmonary artery pulsatility and mortality after implantation of left ventricular assist device

International audienceAbstract Aims Right ventricular failure after left ventricular assist device (LVAD) implantation is a major concern that remains challenging to predict. We sought to investigate the relationship between preoperative pulmonary artery pulsatility index (PAPi) and mortality after LVAD implantation. Methods and results A retrospective analysis of the ASSIST‐ICD multicentre registry allowed the assessment of PAPi before LVAD according to the formula [(systolic pulmonary artery pressure − diastolic pulmonary artery pressure)/central venous pressure]. The primary endpoint was survival at 3 months, according to the threshold value of PAPi determined by the receiver operating characteristic (ROC) curve. A multivariate analysis including demographic, echographic, haemodynamic, and biological variables was performed to identify predictive factors for 2 year mortality. One hundred seventeen patients were included from 2007 to 2021. The mean age was 58.45 years (±13.16), with 15.4% of women (sex ratio 5.5). A total of 53.4% were implanted as bridge to transplant and 43.1% as destination therapy. Post‐operative right ventricular failure was observed in 57 patients (48.7%), with no significant difference between survivors and non‐survivors at 1 month (odds ratio 1.59, P = 0.30). The median PAPi for the whole study population was 2.83 [interquartile range 1.63–4.69]. The threshold value of PAPi determined by the ROC curve was 2.84. Patients with PAPi ≥ 2.84 had a higher survival rate at 3 months [PAPi < 2.84: 58.1% [46.3–72.8%] vs. PAPi ≥ 2.84: 89.1% [81.1–97.7%], hazard ratio (HR) 0.08 [0.02–0.28], P < 0.01], with no significant difference after 3 months (HR 0.67 [0.17–2.67], P = 0.57). Other predictors of 2 year mortality were systemic hypertension (HR 4.22 [1.49–11.97], P < 0.01) and diabetes mellitus (HR 4.90 [1.83–13.14], P < 0.01). LVAD implantation as bridge to transplant (HR 0.18 [0.04–0.74], P = 0.02) and heart transplantation (HR 0.02 [0.00–0.18], P < 0.01) were associated with a higher survival rate at 2 years. Conclusions Preoperative PAPi < 2.84 was associated with a higher risk of early mortality after LVAD implantation without impacting 2 year outcomes among survivors

Omega-3 fatty acids regulate gene expression levels differently in subjects carrying the PPARα L162V polymorphism

Omega-3 fatty acids (FAs) are natural ligands of the peroxisome proliferator-activated receptor-α (PPARα), a nuclear receptor that modulates expression levels of genes involved in lipid metabolism. The L162V polymorphism of the PPARα gene is associated with a deteriorated metabolic profile. We postulate that subjects carrying the PPARα-V162 allele exhibit differences in the expression of PPARα and its target genes after incubation with omega-3 FAs compared with L162 homozygotes. Peripheral blood monocytes from six men carrying the PPARα-V162 allele paired for age and for body mass index with six L162 homozygotes were differentiated into macrophages and activated with eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), or mixtures of EPA:DHA. Data demonstrates that gene expression levels of PPARα and apolipoprotein AI (APOA1) were significantly lower for carriers of the PPARα-V162 allele compared to L162 homozygotes after the addition of DHA and a mixture of EPA:DHA. Additionally, lipoprotein lipase (LPL) gene expression displayed a tendency to be lower in the PPARα L162V polymorphism subgroup after the addition of a mixture of EPA:DHA. Consequently, individuals carrying the PPARα-V162 allele may demonstrate inferior improvements in their lipid profile due to alterations in gene expression rates in response to omega-3 FA supplementation

Right ventriculoarterial coupling surrogates and long-term survival in LVAD recipients: Results of the ASSIST-ICD multicentric registry

International audienceBackground: Prediction of outcomes remains an unmet need in LVAD candidates. Development of right heart failure portends an excess in mortality but imaging parameters of right ventricular systolic function have failed to demonstrate a prognostic role. By integrating pulmonary pressure, right ventriculoarterial coupling could fill this gap.Methods: The ASSIST-ICD registry was used to test right ventriculoarterial coupling surrogate parameters at implantation for the prediction of all-cause mortality.Results: The ratio of the tricuspid annular plane systolic excursion over the estimated systolic pulmonary pressure (TAPSE/sPAP) was not associated with long-term survival in univariate analysis (p = 0.89), neither was the pulmonary artery pulsatility index (PAPi) (p = 0.13). Conversely, the ratio of the right atrial pressure over the pulmonary capillary wedge pressure (RAP/PCWP) was associated with all-cause mortality (p <0.01). After taking tricuspid regurgitation severity, LVAD indication, LVAD model, age, blood urea nitrogen, and pulmonary vascular resistance into account, RAP/PCWP remained associated with survival (HR 1.35 [1.10 - 1.65], p <0.01).Conclusion: Among pre-implant RVAC surrogates, only RAP/PCWP was associated with long-term all-cause mortality in LVAD recipients. This association was independent of established risk factors