Influence of implant strategy on the transition from temporary left ventricular assist device to durable mechanical circulatory support.

OBJECTIVES: Bridging from a temporary microaxial left ventricular assist device (tLVAD) to a durable left ventricular assist device (dLVAD) is playing an increasing role in the treatment of terminally ill patients with heart failure. Scant data exist about the best implant strategy. The goal of this study was to analyse differences in the dLVAD implant technique and effects on patient outcomes. METHODS: Data from 341 patients (19 European centres) who underwent a bridge-to-bridge implant from tLVAD to dLVAD between January 2017 and October 2022 were retrospectively analysed. The outcomes of the different implant techniques with the patient on cardiopulmonary bypass, extracorporeal life support or tLVAD were compared. RESULTS: A durable LVAD implant was performed employing cardiopulmonary bypass in 70% of cases (n = 238, group 1), extracorporeal life support in 11% (n = 38, group 2) and tLVAD in 19% (n = 65, group 3). Baseline characteristics showed no significant differences in age (P = 0.140), body mass index (P = 0.388), creatinine level (P = 0.659), the Model for End-Stage Liver Disease (MELD) score (P = 0.190) and rate of dialysis (P = 0.110). Group 3 had significantly fewer patients with preoperatively invasive ventilation and cardiopulmonary resuscitation before the tLVAD was implanted (P = 0.009 and P < 0.001 respectively). Concomitant procedures were performed more often in groups 1 and 2 compared to group 3 (24%, 37% and 5%, respectively, P < 0.001). The 30-day mortality data showed significantly better survival after an inverse probability of treatment weighting in group 3, but the 1-year mortality showed no significant differences among the groups (P = 0.012 and 0.581, respectively). Postoperative complications like the rate of right ventricular assist device (RVAD) implants or re-thoracotomy due to bleeding, postoperative respiratory failure and renal replacement therapy showed no significant differences among the groups. Freedom from the first adverse event like stroke, driveline infection or pump thrombosis during follow-up was not significantly different among the groups. Postoperative blood transfusions within 24 h were significantly higher in groups 1 and 2 compared to surgery on tLVAD support (P < 0.001 and P = 0.003, respectively). CONCLUSIONS: In our analysis, the transition from tLVAD to dLVAD without further circulatory support did not show a difference in postoperative long-term survival, but a better 30-day survival was reported. The implant using only tLVAD showed a reduction in postoperative transfusion rates, without increasing the risk of postoperative stroke or pump thrombosis. In this small cohort study, our data support the hypothesis that a dLVAD implant on a tLVAD is a safe and feasible technique in selected patients.

Characteristics and outcomes of COVID-19 in heart transplantation recipients in the Netherlands.

BACKGROUND: Immunocompromised patients are at high risk of complicated severe acute respiratory coronavirus 2 infection. The aim of this retrospective study was to describe the characteristics and outcomes of heart transplantation (HTx) recipients with coronavirus disease 2019 (COVID-19) in the Netherlands. METHODS: HTx patients from one of the three HTx centres in the Netherlands with COVID-19 (proven by positive reverse-transcription polymerase chain reaction or serology test result) between February 2020 and June 2021 were included. The primary endpoint was all-cause mortality and the secondary endpoint was disease severity. RESULTS: COVID-19 was diagnosed in 54/665 HTx patients (8%), with a mean (±â€¯standard deviation (SD)) time after HTx of 11 ± 8 years. Mean (±â€¯SD) age was 53 ± 14 years and 39% were female. Immunosuppressive therapy dosage was reduced in 37% patients (20/54). Hospitalisation was required in 39% patients (21/54), and 13% patients (7/54) had severe COVID-19 (leading to intensive care unit (ICU) admission or death). In-hospital mortality was 14% (3/21), and all-cause mortality was 6%. Compared with patients with moderate COVID-19 (hospitalised without ICU indication), severe COVID-19 patients tended to be transplanted earlier and had a significantly higher mean (±â€¯SD) body mass index (26 ± 3 vs 30 ± 3 kg/m2, p = 0.01). Myocardial infarction, cellular rejection and pulmonary embolism were observed once in three different HTx patients. CONCLUSION: HTx patients were at increased risk of complicated COVID-19 with frequent hospitalisation, but the all-cause mortality was substantially lower than previously described (7-33%).

The frequency of snowline-region planets from four-years of OGLE-MOA-Wise second-generation microlensing.

We present a statistical analysis of the first four seasons from a "second-generation" microlensing survey for extrasolar planets, consisting of near-continuous time coverage of 8 deg2 of the Galactic bulge by the OGLE, MOA, and Wise microlensing surveys. During this period, 224 microlensing events were observed by all three groups. Over 12% of the events showed a deviation from single-lens microlensing, and for ~1/3 of those the anomaly is likely caused by a planetary companion. For each of the 224 events we have performed numerical ray-tracing simulations to calculate the detection efficiency of possible companions as a function of companion-to-host mass ratio and separation. Accounting for the detection efficiency, we find that 55 - 22 + 34 % of microlensed stars host a snowline planet. Moreover, we find that Neptunes-mass planets are ~ 10 times more common than Jupiter-mass planets. The companion-to-host mass ratio distribution shows a deficit at q ~ 10-2, separating the distribution into two companion populations, analogous to the stellar-companion and planet populations, seen in radial-velocity surveys around solar-like stars. Our survey, however, which probes mainly lower-mass stars, suggests a minimum in the distribution in the super-Jupiter mass range, and a relatively high occurrence of brown-dwarf companions.

Extremely metal-poor stars from the cosmic dawn in the bulge of the Milky Way.

The first stars are predicted to have formed within 200 million years after the Big Bang, initiating the cosmic dawn. A true first star has not yet been discovered, although stars with tiny amounts of elements heavier than helium ('metals') have been found in the outer regions ('halo') of the Milky Way. The first stars and their immediate successors should, however, preferentially be found today in the central regions ('bulges') of galaxies, because they formed in the largest over-densities that grew gravitationally with time. The Milky Way bulge underwent a rapid chemical enrichment during the first 1-2 billion years, leading to a dearth of early, metal-poor stars. Here we report observations of extremely metal-poor stars in the Milky Way bulge, including one star with an iron abundance about 10,000 times lower than the solar value without noticeable carbon enhancement. We confirm that most of the metal-poor bulge stars are on tight orbits around the Galactic Centre, rather than being halo stars passing through the bulge, as expected for stars formed at redshifts greater than 15. Their chemical compositions are in general similar to typical halo stars of the same metallicity although intriguing differences exist, including lower abundances of carbon.

Exoplanet detection. A terrestrial planet in a ~1-AU orbit around one member of a ~15-AU binary.

Using gravitational microlensing, we detected a cold terrestrial planet orbiting one member of a binary star system. The planet has low mass (twice Earth's) and lies projected at ~0.8 astronomical units (AU) from its host star, about the distance between Earth and the Sun. However, the planet's temperature is much lower, <60 Kelvin, because the host star is only 0.10 to 0.15 solar masses and therefore more than 400 times less luminous than the Sun. The host itself orbits a slightly more massive companion with projected separation of 10 to 15 AU. This detection is consistent with such systems being very common. Straightforward modification of current microlensing search strategies could increase sensitivity to planets in binary systems. With more detections, such binary-star planetary systems could constrain models of planet formation and evolution.

An eclipsing-binary distance to the Large Magellanic Cloud accurate to two per cent.

In the era of precision cosmology, it is essential to determine the Hubble constant to an accuracy of three per cent or better. At present, its uncertainty is dominated by the uncertainty in the distance to the Large Magellanic Cloud (LMC), which, being our second-closest galaxy, serves as the best anchor point for the cosmic distance scale. Observations of eclipsing binaries offer a unique opportunity to measure stellar parameters and distances precisely and accurately. The eclipsing-binary method was previously applied to the LMC, but the accuracy of the distance results was lessened by the need to model the bright, early-type systems used in those studies. Here we report determinations of the distances to eight long-period, late-type eclipsing systems in the LMC, composed of cool, giant stars. For these systems, we can accurately measure both the linear and the angular sizes of their components and avoid the most important problems related to the hot, early-type systems. The LMC distance that we derive from these systems (49.97 ± 0.19 (statistical) ± 1.11 (systematic) kiloparsecs) is accurate to 2.2 per cent and provides a firm base for a 3-per-cent determination of the Hubble constant, with prospects for improvement to 2 per cent in the future.

Increased cardiovascular risk in rats with primary renal dysfunction; mediating role for vascular endothelial function.

Primary chronic kidney disease is associated with high cardiovascular risk. However, the exact mechanisms behind this cardiorenal interaction remain unclear. We investigated the interaction between heart and kidneys in novel animal model for cardiorenal interaction. Normal Wistar rats and Munich Wistar Fromter rats, spontaneously developing renal dysfunction, were subjected to experimental myocardial infarction to induce cardiac dysfunction (CD) and combined cardiorenal dysfunction (CRD), respectively (N = 5-10). Twelve weeks later, cardiac- and renal parameters were evaluated. Cardiac, but not renal dysfunction was exaggerated in CRD. Accelerated cardiac dysfunction in CRD was indicated by decreased cardiac output (CD 109 ± 10 vs. CRD 79 ± 8 ml/min), diastolic dysfunction (E/e') (CD 26 ± 2 vs. CRD 50 ± 5) and left ventricular overload (LVEDP CD 10.8 ± 2.8 vs. CRD 21.6 ± 1.7 mmHg). Congestion in CRD was confirmed by increased lung and atrial weights, as well as exaggerated right ventricular hypertrophy. Absence of accelerated renal dysfunction, measured by increased proteinuria, was supported by absence of additional focal glomerulosclerosis or further decline of renal blood flow in CRD. Only advanced peripheral endothelial dysfunction, as found in CRD, appeared to correlate with both renal and cardiac dysfunction parameters. Thus, proteinuric rats with myocardial infarction showed accelerated cardiac but not renal dysfunction. As parameters mimic the cardiorenal syndrome, these rats may provide a clinically relevant model to study increased cardiovascular risk due to renal dysfunction. Peripheral endothelial dysfunction was the only parameter that correlated with both renal and cardiac dysfunction, which may indicate a mediating role in cardiorenal interaction.

One or more bound planets per Milky Way star from microlensing observations.

Most known extrasolar planets (exoplanets) have been discovered using the radial velocity or transit methods. Both are biased towards planets that are relatively close to their parent stars, and studies find that around 17-30% (refs 4, 5) of solar-like stars host a planet. Gravitational microlensing, on the other hand, probes planets that are further away from their stars. Recently, a population of planets that are unbound or very far from their stars was discovered by microlensing. These planets are at least as numerous as the stars in the Milky Way. Here we report a statistical analysis of microlensing data (gathered in 2002-07) that reveals the fraction of bound planets 0.5-10 AU (Sun-Earth distance) from their stars. We find that 17(+6)(-9)% of stars host Jupiter-mass planets (0.3-10 M(J), where M(J) = 318 M(⊕) and M(⊕) is Earth's mass). Cool Neptunes (10-30 M(⊕)) and super-Earths (5-10 M(⊕)) are even more common: their respective abundances per star are 52(+22)(-29)% and 62(+35)(-37)%. We conclude that stars are orbited by planets as a rule, rather than the exception.

Discovery of a Jupiter/Saturn analog with gravitational microlensing.

Searches for extrasolar planets have uncovered an astonishing diversity of planetary systems, yet the frequency of solar system analogs remains unknown. The gravitational microlensing planet search method is potentially sensitive to multiple-planet systems containing analogs of all the solar system planets except Mercury. We report the detection of a multiple-planet system with microlensing. We identify two planets with masses of approximately 0.71 and approximately 0.27 times the mass of Jupiter and orbital separations of approximately 2.3 and approximately 4.6 astronomical units orbiting a primary star of mass approximately 0.50 solar mass at a distance of approximately 1.5 kiloparsecs. This system resembles a scaled version of our solar system in that the mass ratio, separation ratio, and equilibrium temperatures of the planets are similar to those of Jupiter and Saturn. These planets could not have been detected with other techniques; their discovery from only six confirmed microlensing planet detections suggests that solar system analogs may be common.

Discovery of a cool planet of 5.5 Earth masses through gravitational microlensing.

In the favoured core-accretion model of formation of planetary systems, solid planetesimals accumulate to build up planetary cores, which then accrete nebular gas if they are sufficiently massive. Around M-dwarf stars (the most common stars in our Galaxy), this model favours the formation of Earth-mass (M(o)) to Neptune-mass planets with orbital radii of 1 to 10 astronomical units (au), which is consistent with the small number of gas giant planets known to orbit M-dwarf host stars. More than 170 extrasolar planets have been discovered with a wide range of masses and orbital periods, but planets of Neptune's mass or less have not hitherto been detected at separations of more than 0.15 au from normal stars. Here we report the discovery of a 5.5(+5.5)(-2.7) M(o) planetary companion at a separation of 2.6+1.5-0.6 au from a 0.22+0.21-0.11 M(o) M-dwarf star, where M(o) refers to a solar mass. (We propose to name it OGLE-2005-BLG-390Lb, indicating a planetary mass companion to the lens star of the microlensing event.) The mass is lower than that of GJ876d (ref. 5), although the error bars overlap. Our detection suggests that such cool, sub-Neptune-mass planets may be more common than gas giant planets, as predicted by the core accretion theory.

Search for low-mass exoplanets by gravitational microlensing at high magnification.

Observations of the gravitational microlensing event MOA 2003-BLG-32/OGLE 2003-BLG-219 are presented, for which the peak magnification was over 500, the highest yet reported. Continuous observations around the peak enabled a sensitive search for planets orbiting the lens star. No planets were detected. Planets 1.3 times heavier than Earth were excluded from more than 50% of the projected annular region from approximately 2.3 to 3.6 astronomical units surrounding the lens star, Uranus-mass planets were excluded from 0.9 to 8.7 astronomical units, and planets 1.3 times heavier than Saturn were excluded from 0.2 to 60 astronomical units. These are the largest regions of sensitivity yet achieved in searches for extrasolar planets orbiting any star.