Postoperative high-sensitivity troponin T as a predictor of sudden cardiac arrest in patients undergoing cardiac surgery

Background: The usefulness of high-sensitivity troponin T (hs-TnT) as a predictor of sudden cardiacarrest (SCA) in patients undergoing valve surgery is currently unknown.Methods: A prospective study was conducted on a group of 815 consecutive patients with significantvalvular heart disease that underwent elective valve surgery. The primary end-point was postoperative SCA.Results: The postoperative SCA occurred in 26 patients. At multivariate analysis of hs-TnT measuredimmediately after surgery (hs-TnT I) and age remained independent predictors of the primary end-point.Conclusions: Elevated postoperative hs-TnT was associated with a higher risk of postoperative SCA

Anisocytosis predicts postoperative renal replacement therapy in patients undergoing heart valve surgery

Background: Acute kidney injury (AKI) is one of the serious postoperative complications in patients undergoing heart valve surgery. The aim of the present study was to identify selected biomarkers to predict AKI requiring renal replacement.Methods: A prospective study was conducted on a group of 751 patients undergoing heart valve surgery. The data on risk factors, preoperative complete blood count, course of operations and postoperative period was assessed. The primary endpoint at the 30-day follow-up was postoperative AKI requiring renal replacement therapy. The secondary end-point was death from all causes in patients with postoperative AKI requiring renal replacement.Results: The primary endpoint occurred in 46 patients. At multivariate analysis: age, red cell distribution width (RDW) and C-reactive protein remained independent predictors of the primary endpoint. Hemoglobin and RDW were associated with an increased risk of death.Conclusions: Elevated RDW is associated with a higher risk of postoperative AKI and death in patients with AKI

The usefulness of selected biomarkers in aortic regurgitation

Background: The aim of the study was to investigate the prognostic value of selected biomarkers inpatients with aortic regurgitation undergoing valve surgery. Methods: A prospective study was conducted on a group of consecutive patients with hemodynamically significant aortic regurgitation that underwent elective aortic valve surgery. The primary endpoint was 30-day mortality and any major adverse event within 30 days. Results: The study group included 205 consecutive patients who underwent replacement or repair of the aortic valve. The primary endpoint occurred in 72 patients. At multivariate analysis red cell distribution width (RDW; p = 0.03) and high-sensitivity troponin T (hs-TnT; p = 0.02) remained independent predictors of the major complications including death. Conclusions: Elevated preoperative RDW and hs-TnT were associated with a poorer outcome followingaortic valve surgery

Prior specification via prior predictive matching: Poisson matrix factorization and beyond

Hyperparameter optimization for machine learning models is typically carried out by some sort of cross-validation procedure or global optimization, both of which require running the learning algorithm numerous times. We show that for Bayesian hierarchical models there is an appealing alternative that allows selecting good hyperparameters without learning the model parameters during the process at all, facilitated by the prior predictive distribution that marginalizes out the model parameters. We propose an approach that matches suitable statistics of the prior predictive distribution with ones provided by an expert and apply the general concept for matrix factorization models. For some Poisson matrix factorization models we can analytically obtain exact hyperparameters, including the number of factors, and for more complex models we propose a model-independent optimization procedure

Literature-based considerations regarding organizing and performing cardiac surgery against the backdrop of the coronavirus pandemic

Background: The ongoing coronavirus disease 2019 (Covid-19) pandemic presents challenges for surgeons of all disciplines, including cardiologists. The volume of cardiac surgery cases has to comply with the mandatory constraints of healthcare capacities. The treatment of Covid-19-positive patients must also be considered. Unfortunately, no scientific evidence is available on this issue. Therefore, this study aimed to offer some consensus-based considerations, derived from available scientific papers, regarding the organization and performance of cardiac surgery against the backdrop of the Covid-19 pandemic. Methods Key recommendations were extracted from recent literature concerning cardiac surgery. RESULTS: Reducing elective cardiac procedures should be based on frequent clinical assessment of patients on the waiting list (every one or two weeks) and the current local status of the Covid-19 pandemic. Screening tests at admission for every patient are broadly recommended. Where appropriate, alternative treatment methods can be considered, including percutaneous techniques and minimally invasive surgery, if performed by experienced cardiac surgery teams. Conclusions There is little evidence on the strategies to organize cardiac surgery in the Covid-19 pandemic. Most authors agree on reducing elective operations based on patients' clinical condition and the status of the Covid-19 pandemic. Admission screenings and the use of percutaneous or minimally invasive approaches should be preferred to reduce in-hospital stays

Hypernetwork approach to Bayesian MAML

The main goal of Few-Shot learning algorithms is to enable learning from small amounts of data. One of the most popular and elegant Few-Shot learning approaches is Model-Agnostic Meta-Learning (MAML). The main idea behind this method is to learn the shared universal weights of a meta-model, which are then adapted for specific tasks. However, the method suffers from over-fitting and poorly quantifies uncertainty due to limited data size. Bayesian approaches could, in principle, alleviate these shortcomings by learning weight distributions in place of point-wise weights. Unfortunately, previous modifications of MAML are limited due to the simplicity of Gaussian posteriors, MAML-like gradient-based weight updates, or by the same structure enforced for universal and adapted weights. In this paper, we propose a novel framework for Bayesian MAML called BayesianHMAML, which employs Hypernetworks for weight updates. It learns the universal weights point-wise, but a probabilistic structure is added when adapted for specific tasks. In such a framework, we can use simple Gaussian distributions or more complicated posteriors induced by Continuous Normalizing Flows.Comment: arXiv admin note: text overlap with arXiv:2205.1574

Raised red cell distribution width as a prognostic marker in aortic valve replacement surgery

Background and aim: Several studies have reported that elevated red cell distribution width (RDW) is associated with poor outcomes in patients with coronary artery disease, chronic heart failure and aortic stenosis following transcatheter aortic valve replacement. Their prognostic utility in patients undergoing aortic valve replacement (AVR) surgery is unknown. Methods: We prospectively evaluated the prognostic value of RDW in a group of 191 consecutive patients with severe symptomatic aortic stenosis undergoing AVR. The pre-defined primary endpoint at the 30-day follow-up was composed of: all cause mortality, perioperative myocardial infarction, perioperative renal failure, prolonged mechanical ventilation, stroke, heart failure, successfully resuscitated cardiac arrest, the occurrence of multiple-organ failure, and the need for additional surgery for any reason. The secondary endpoint was total mortality. Results: The composite endpoint occurred in 54 patients. In univariate analysis RDW (p < 0.0001), haemoglobin level (p = 0.005), haematocrit (p = 0.01), red blood cell count (RBC; p = 0.002), glomerular filtration rate (p = 0.003), New York Heart Association classification (p = 0.02), atrial fibrillation (p = 0.0044), and pulmonary blood pressure (p = 0.004) were associated with the occurrence of the composite endpoint. RDW (p = 0.0005), haemoglobin level (p = 0.004), haematocrit (p = 0.004), RBC (p = 0.0009) and mean corpuscular volume (p = 0.01) were associated with an increased risk of death. In multivariate analysis, RDW (OR 3.274; 95% CI 1.285–8.344; p = 0.0003) and RBC (OR 0.373; 95% CI 0.176–0.787; p = 0.0097) remained independent predictors of the composite endpoint. Receiver operating characteristic analysis determined a cut-off value of RDW for the prediction of the occurrence of the combined endpoint at 14.1%. Conclusions: Elevated RDW is associated with a worse outcome following AVR, independent of RBC.  Wstęp: W dotychczasowych badaniach wykazano, że podwyższone wartości rozkładu objętości erytrocytów (RDW) są związane z gorszym rokowaniem u osób z chorobą wieńcową, niewydolnością serca czy ciężką stenozą aortalną leczoną przezcewnikowym wszczepieniem zastawki aortalnej. Znaczenie RDW u pacjentów poddawanych operacji chirurgicznej wymiany zastawki aortalnej jest nieznane. Cel: Celem niniejszej pracy była ocena wartości prognostycznej RDW u chorych poddawanych operacyjnemu leczeniu ciężkiej stenozy aortalnej. Metody: Prospektywne badanie przeprowadzono w grupie kolejnych 191 pacjentów z ciężką objawową stenozą aortalną poddawanych operacyjnemu leczeniu wymiany zastawki aortalnej. Na z góry zdefiniowany pierwszorzędowy złożony punkt końcowy w obserwacji 30-dniowej składało się wystąpienie następujących powikłań: zgonu z wszystkich przyczyn, okołozabiegowego zawału serca, okołooperacyjnej niewydolności nerek, przedłużonej wentylacji mechanicznej, udaru ośrodkowego układu nerwowego, skutecznie resuscytowanego zatrzymania akcji serca, niewydolności wielonarządowej i konieczności reoperacji z jakiejkolwiek przyczyny. Drugorzędowym punktem końcowym była śmiertelność. Wyniki: Pierwszorzędowy złożony punkt końcowy w obserwacji 30-dniowej zaobserwowano u 54 pacjentów. W analizie jednoczynnikowej predyktorami wystąpienia pierwszorzędowego punktu końcowego były: RDW (p < 0,0001), hemoglobina (p = 0,005), hematokryt (p = 0,01), liczba erytrocytów (p = 0,002), wskaźnik przesączania kłębuszkowego (p = 0,003), stopień niewydolności serca wg klasyfikacji NYHA (p = 0,02), migotanie przedsionków (p = 0,0044) i ciśnienie w tętnicy płucnej (p = 0,004). Wartości RDW (p = 0,0005), hemoglobiny (p = 0,004), hematokrytu (p = 0,004), liczba erytrocytów (p = 0,0009) i średnia objętość erytrocytów (p = 0.01) wiązały się ze zwiększonym ryzykiem wystąpienia zgonu. Analiza wieloczynnikowa potwierdziła znaczenie RDW (OR 3.274; 95% Cl 1,285–8,344; p = 0,0003) jako niezależnego predyktora wystąpienia pierwszorzędowego złożonego punktu końcowego. Przy użyciu statystyki krzywej ROC wyznaczono punkt odcięcia RDW dla wystąpienia złożonego punktu końcowego na poziomie 14,1% (pole pod krzywą 0,07; p = 0,008). Wnioski: Wyższe wartości RDW są związane z gorszym rokowaniem u pacjentów poddawanych operacji wymiany zastawki aortalnej, niezależnie od liczby erytrocytów.

Prevalence and management of driveline infections in mechanical circulatory support - a single center analysis

Background: Driveline infections in continuous-flow left ventricular assist devices (cf-LVAD) remain the most common adverse event. This single-center retrospective study investigated the risk factors, prevalence and management of driveline infections. :Methods Patients treated after cf-LVAD implantation from December 2014 to January 2020 were enrolled. Baseline data were collected and potential risk factors were elaborated. The multi-modal treatment was based on antibiotic therapy, daily wound care, surgical driveline reposition, and heart transplantation. Time of infection development, freedom of reinfection, freedom of heart transplantation, and death in the follow-up time were investigated. Results: Of 75 observed patients, 26 (34.7%) developed a driveline infection. The mean time from implantation to infection diagnosis was 463 (+/- 399; range, 35-1400) days. The most common pathogen was Staphylococcus aureus (n = 15, 60%). First-line therapy was based on antibiotics, with a primary success rate of 27%. The majority of patients (n = 19; 73.1%) were treated with surgical reposition after initial antibiotic therapy. During the follow-up time of 569 (+/- 506; range 32-2093) days, the reinfection freedom after surgical transposition was 57.9%. Heart transplantation was performed in eight patients due to resistant infection. The overall mortality for driveline infection was 11.5%. Conclusions: Driveline infections are frequent in patients with implanted cf-LVAD, and treatment does not efficiently avoid reinfection, leading to moderate mortality rates. Only about a quarter of the infected patients were cured with antibiotics alone. Surgical driveline reposition is a reasonable treatment option and does not preclude subsequent heart transplantation due to limited reinfection freedom