Changes and prognostic value of cardiopulmonary exercise testing parameters in elderly patients undergoing cardiac rehabilitation: The EU-CaRE observational study

Objective We aimed 1) to test the applicability of the previously suggested prognostic value of CPET to elderly cardiac rehabilitation patients and 2) to explore the underlying mechanism of the greater improvement in exercise capacity (peak oxygen consumption, VO2) after CR in surgical compared to non-surgical cardiac patients. Methods Elderly patients (?65 years) commencing CR after coronary artery bypass grafting, surgical valve replacement (surgery-group), percutaneous coronary intervention, percutaneous valve replacement or without revascularisation (non-surgery group) were included in the prospective multi-center EU-CaRE study. CPETs were performed at start of CR, end of CR and 1-year-follow-up. Logistic models and receiver operating characteristics were used to determine prognostic values of CPET parameters for major adverse cardiac events (MACE). Linear models were performed for change in peak VO2 (start to follow-up) and parameters accounting for the difference between surgery and non-surgery patients were sought. Results 1421 out of 1633 EU-CaRE patients performed a valid CPET at start of CR (age 73±5.4, 81% male). No CPET parameter further improved the receiver operation characteristics significantly beyond the model with only clinical parameters. The higher improvement in peak VO2 (25% vs. 7%) in the surgical group disappeared when adjusted for changes in peak tidal volume and haemoglobin. Conclusion CPET did not improve the prediction of MACE in elderly CR patients. The higher improvement of exercise capacity in surgery patients was mainly driven by restoration of haemoglobin levels and improvement in respiratory function after sternotomy

Hydrodynamic behavior analysis of a rotating disc contactor for aromatics extraction with 4-methyl-butyl-pyridinium-BF4 by CFD

An experimental and numerical simulation analysis of the hydrodynamic behavior for aromatics extraction with 4-methyl-N-butyl-pyridinium tetrafluoroborate is presented. Room temperature ionic liquids (RTILs) have proven to be promising solvents for the extraction of aromatic hydrocarbons, because of their non-volatile nature and their tailoring properties. The RTIL 4-methyl-N-butyl-pyridinium tetrafluoroborate ([4-mebupy]BF4) was therefore tested as a solvent for the extraction of toluene from toluene/n-heptane in a rotating disc contactor (RDC). Hydrodynamic characteristics, like Sauter mean diameter and hold-up, were measured for different total fluxes and stirrer speeds. Unexpected behavior for the hold-up was observed in experiments when the RTIL was applied as solvent. At lower fluxes, the hold-up decreases with increasing rotor speed, when an increase of hold-up was expected. This behavior, however, can very well be explained by the existence of three operating regimes in the used RDC.Computational fluid dynamics simulations of the two-phase flow in the RDC extractor have been performed to investigate the unexpected hold-up behavior. The numerical simulations were done using the commercial CFD software fluent, whereas an Euler–Euler model was applied together with the realizable k– turbulence model for the solution of the liquid–liquid problem. The numerical hold-up results are compared to the experimental profiles. Possible reasons for the hold-up anomalies, namely the path of the RTIL droplets as well as the velocity fields in both liquid phases, are presented and discussed. The work shows, that CFD can predict hydrodynamic characteristics even for extreme examples as in the present RTIL extraction

Participation and adherence to cardiac rehabilitation programs. A systematic review

Acute myocardial infarction (AMI) is an important health problem. Cardiac rehabilitation (CR) programs following AMI have shown to be effective in reducing mortality. We aim to systematically review the existing literature that analyzes the factors that affect participation and adherence to cardiac rehabilitation programs. We reviewed Medline, EMBASE and Cochrane databases from 01/01/2004 to June 2016 using predefined inclusion and exclusion criteria. We classified the results into factors affecting participation and factors influencing adherence to CR programs. We included 29 studies, and there was a general agreement in those factors predicting participation and adherence to CR programs. These factors can be classified into person-related factors and aspects related to CR programs. Older participants, women, patients with comorbidities, unemployed and uncoupled persons, less educated people and those with lower income had a lower participation. A similar pattern was observed for CR adherence. Also, those potential participants who live farther from CR facilities, do not have transportation, or do not drive, attended less to CR programs. These factors were very similar when analyzing adherence to CR programs. These aspects were similar in Europe and the USA. These results clearly show that participation in CR programs follows a determined pattern that is very homogeneous in different settings. Health professionals should also be aware of patients reluctant to participate in CR programs and adapt their messages and redesign CR programs, to promote participation and adherence