Category: Nevin Manimala

J Interv Card Electrophysiol. 2023 Feb 9. doi: 10.1007/s10840-023-01494-z. Online ahead of print.

ABSTRACT

BACKGROUND: To date, few risk models have been validated to predict recurrent atrial fibrillation (AF) >1 year after ablation. The SCALE-CryoAF score was previously derived to predict very late return of AF (VLRAF) >1 year following cryoballoon ablation (CBA), with strong predictive ability. In this study, we aim to validate the SCALE-CryoAF score for VLRAF after CBA in a novel patient cohort.

METHODS: Retrospective analysis of a prospectively maintained single-center database was performed. Inclusion criteria were pulmonary vein isolation using CBA 2017-2020. Exclusion criteria included prior ablation, <1-year follow-up, lack of pre-CBA echocardiogram, additional ablation lesion sets, and documented AF recurrence 90-365 days post-CBA. The area under the curve (AUC) of SCALE-CryoAF was compared to the derivation value and other established risk models.

RESULTS: Among 469 CBA performed, 241 (61% male, 62.8 ±11.7 years old) cases were included in analysis. There were 37 (15.4%) patients who developed VLRAF. Patients with VLRAF had a higher SCALE-CryoAF score (VLRAF 5.4 ± 2.7; no VLRAF 3.1 ± 2.9; p<0.001). SCALE-CryoAF was linearly associated with VLRAF (y=14.35x-11.72, R²=0.99), and a score > 5 had a 32.7% risk of VLRAF. The SCALE-CryoAF risk model predicted VLRAF with an AUC of 0.74, which was similar to the derivation value (AUC_derivation: 0.73) and statistically superior to MB-LATER, CHA2DS2-VASc, and CHADS₂ scores.

CONCLUSIONS: The current analysis validates the ability of SCALE-CryoAF to predict VLRAF after CBA in a novel patient cohort. Patients with a high SCALE-CryoAF score should be monitored closely for recurrent AF >1 year following CBA.

PMID:36754907 | DOI:10.1007/s10840-023-01494-z

Eur Radiol. 2023 Feb 9. doi: 10.1007/s00330-023-09426-1. Online ahead of print.

ABSTRACT

OBJECTIVES: To study the impact of COVID-19 on chest CT practice during the different waves using Dose Archiving and Communication System (DACS).

METHODS: Retrospective study including data from 86,136 chest CT acquisitions from 27 radiology centers (15 private; 12 public) between January 1, 2020, and October 13, 2021, using a centralized DACS. Daily chest CT activity and dosimetry information such as dose length product (DLP), computed tomography dose index (CTDI), and acquisition parameters were collected. Pandemic indicators (daily tests performed, incidence, and hospital admissions) and vaccination rates were collected from a governmental open-data platform. Descriptive statistics and correlation analysis were performed.

RESULTS: For the first two waves, strong positive and significant correlations were found between all pandemic indicators and total chest CT activity, as high as R = 0.7984 between daily chest CT activity and hospital admissions during the second wave (p < 0.0001). We found differences between public hospitals and private imaging centers during the first wave, with private centers demonstrating a negative correlation between daily chest CT activity and hospital admissions (-0.2819, p = 0.0019). Throughout the third wave, simultaneously with the rise of vaccination rates, total chest CT activity decreased with significant negative correlations with pandemic indicators, such as R = -0.7939 between daily chest CTs and daily incidence (p < 0.0001). Finally, less than 5% of all analyzed chest CTs could be considered as low dose.

CONCLUSIONS: During the first waves, COVID-19 had a strong impact on chest CT practice which was lost with the arrival of vaccination. Low-dose protocols remained marginal.

KEY POINTS: • There was a significant correlation between the number of daily chest CTs and pandemic indicators throughout the first two waves. It was lost during the third wave due to vaccination arrival. • Differences were observed between public and private centers, especially during the first wave, less during the second, and were lost during the third. • During the first three waves of COVID-19 pandemic, few CT helical acquisitions could be considered as low dose with only 3.8% of the acquisitions according to CTDIvol and 4.3% according to DLP.

PMID:36754891 | DOI:10.1007/s00330-023-09426-1

Pediatr Cardiol. 2023 Feb 8. doi: 10.1007/s00246-022-03034-4. Online ahead of print.

ABSTRACT

Earlier diagnosis of chylothorax following pediatric cardiac surgery is associated with decreased duration of chylothorax. Pleural fluid testing is used to diagnosis chylothorax which may delay detection in patients who are not enterally fed at time of chylothorax onset. Our aim was to develop and externally validate a prediction model to detect chylothorax earlier than pleural fluid testing in pediatric patients following cardiac surgery. A multivariable logistic regression model was developed to detect chylothorax using a stepwise approach. The model was developed using data from patients < 18 years following cardiac surgery from Primary Children’s Hospital, a tertiary-care academic center, between 2017 and 2020. External validation used a contemporary cohort (n = 171) from Lucille Packard Children’s Hospital. A total of 763 encounters (735 patients) were analyzed, of which 72 had chylothorax. The final variables selected were chest tube output (CTO) the day after sternal closure (dichotomized at 15.6 mL/kg/day, and as a continuous variable) and delayed sternal closure. The highest odds of chylothorax were associated with CTO on post-sternal closure day 1 > 15.6 mL/kg/day (odds ratio 11.3, 95% CI 6,3, 21.3). The c-statistic for the internal and external validation datasets using the dichotomized CTO variable were 0.78 (95% CI 0.73, 0.82) and 0.84 (95% CI, 0.78, 0.9) and performance improved when using CTO as a continuous variable (OR 0.84, CI: 95% CI 0.80, 0.87). Using the models described, chylothorax after pediatric cardiac surgery may be detected earlier and without reliance on enteral feeds.

PMID:36754886 | DOI:10.1007/s00246-022-03034-4

Surg Endosc. 2023 Feb 8. doi: 10.1007/s00464-023-09931-w. Online ahead of print.

ABSTRACT

BACKGROUND: Nissen fundoplication is considered the cornerstone surgical treatment for hiatal hernia repair. Belsey Mark IV (BMIV) transthoracic fundoplication is an alternative approach that is rarely utilized in today’s minimally invasive era. This study aims to summarize the safety and efficacy of BMIV and to compare it with Nissen fundoplication.

METHODS: We searched MEDLINE, Scopus, and Cochrane Library databases for single arm and comparative studies published by March 31st, 2022, according to PRISMA statement. Inverse-variance weights were used to estimate the proportion of patients experiencing the studied outcome and random-effects meta-analyses were performed.

RESULTS: 17 studies were identified, incorporating 2136 and 638 patients that underwent Belsey Mark IV or Nissen fundoplication, respectively. A total of 13.8% (95% CI: 9.6-18.6) of the patients that underwent fundoplication with the BMIV technique had non-resolution of their symptoms and 3.5% (95% CI: 2.0-5.4) required a reoperation. Overall, 14.8% (95% CI: 9.5-20.1) of the BMIV arm patients experienced post-operative complications, 5.0% (95% CI: 2.0-9.0) experienced chronic postoperative pain and 6.9% (95% CI: 3.1-11.9) had a hernia recurrence. No statistically significant difference was observed between Belsey Mark IV and Nissen fundoplication in terms of post-interventional non-resolution of symptoms (odds ratio [OR]: 1.49 [95% Confidence Interval (95%CI):0.6-4.0]; p = 0.42), post-operative complications (OR:0.83, 95%CI: 0.5-1.5, p = 0.54) and in-hospital mortality (OR:0.69, 95%CI: 0.13-3.80, p = 0.67). Belsey Mark IV arm had significantly lower reoperation rates compared to Nissen arm (OR:0.28, 95%CI: 0.1-0.7, p = 0.01).

CONCLUSIONS: BMIV fundoplication is a safe and effective but technically challenging. The BMIV technique may offer benefits to patients compared to the laparoscopic Nissen fundoplication. These benefits, however, are challenged by the increased morbidity of a thoracotomy.

PMID:36754871 | DOI:10.1007/s00464-023-09931-w

Brief Bioinform. 2023 Feb 8:bbad042. doi: 10.1093/bib/bbad042. Online ahead of print.

ABSTRACT

Feature gene selection has significant impact on the performance of cell clustering in single-cell RNA sequencing (scRNA-seq) analysis. A well-rounded feature selection (FS) method should consider relevance, redundancy and complementarity of the features. Yet most existing FS methods focus on gene relevance to the cell types but neglect redundancy and complementarity, which undermines the cell clustering performance. We develop a novel computational method GeneClust to select feature genes for scRNA-seq cell clustering. GeneClust groups genes based on their expression profiles, then selects genes with the aim of maximizing relevance, minimizing redundancy and preserving complementarity. It can work as a plug-in tool for FS with any existing cell clustering method. Extensive benchmark results demonstrate that GeneClust significantly improve the clustering performance. Moreover, GeneClust can group cofunctional genes in biological process and pathway into clusters, thus providing a means of investigating gene interactions and identifying potential genes relevant to biological characteristics of the dataset. GeneClust is freely available at https://github.com/ToryDeng/scGeneClust.

PMID:36754847 | DOI:10.1093/bib/bbad042

J Chem Phys. 2023 Feb 7;158(5):054113. doi: 10.1063/5.0135249.

ABSTRACT

The transport of particles through channels is of paramount importance in physics, chemistry, and surface science due to its broad real world applications. Much insight can be gained by observing the transition paths of a particle through a channel and collecting statistics on the lifetimes in the channel or the escape probabilities from the channel. In this paper, we consider the diffusive transport through a narrow conical channel of a Brownian particle subject to intermittent dynamics, namely, stochastic resetting. As such, resetting brings the particle back to a desired location from where it resumes its diffusive phase. To this end, we extend the Fick-Jacobs theory of channel-facilitated diffusive transport to resetting-induced transport. Exact expressions for the conditional mean first passage times, escape probabilities, and the total average lifetime in the channel are obtained, and their behavior as a function of the resetting rate is highlighted. It is shown that resetting can expedite the transport through the channel-rigorous constraints for such conditions are then illustrated. Furthermore, we observe that a carefully chosen resetting rate can render the average lifetime of the particle inside the channel minimal. Interestingly, the optimal rate undergoes continuous and discontinuous transitions as some relevant system parameters are varied. The validity of our one-dimensional analysis and the corresponding theoretical predictions is supported by three-dimensional Brownian dynamics simulations. We thus believe that resetting can be useful to facilitate particle transport across biological membranes-a phenomenon that can spearhead further theoretical and experimental studies.

PMID:36754825 | DOI:10.1063/5.0135249

J Chem Phys. 2023 Feb 7;158(5):054903. doi: 10.1063/5.0123431.

ABSTRACT

We present a computationally efficient multiscale method for preparing equilibrated, isotropic long-chain model polymer melts. As an application, we generate Kremer-Grest melts of 1000 chains with 200 entanglements and 25 000-2000 beads/chain, which cover the experimentally relevant bending rigidities up to and beyond the limit of the isotropic-nematic transition. In the first step, we employ Monte Carlo simulations of a lattice model to equilibrate the large-scale chain structure above the tube scale while ensuring a spatially homogeneous density distribution. We then use theoretical insight from a constrained mode tube model to introduce the bead degrees of freedom together with random walk conformational statistics all the way down to the Kuhn scale of the chains. This is followed by a sequence of simulations with carefully parameterized force-capped bead-spring models, which slowly introduce the local bead packing while reproducing the larger-scale chain statistics of the target Kremer-Grest system at all levels of force-capping. Finally, we can switch to the full Kremer-Grest model without perturbing the structure. The resulting chain statistics is in excellent agreement with literature results on all length scales accessible in brute-force simulations of shorter chains.

PMID:36754791 | DOI:10.1063/5.0123431

J Chem Theory Comput. 2023 Feb 8. doi: 10.1021/acs.jctc.2c01094. Online ahead of print.

ABSTRACT

Polarizabilities play significant roles in describing dispersive and inductive interactions of the atom and molecular systems. However, an accurate prediction of molecular polarizabilities from first principles is computationally prohibitive. Although physical models or statistical machine learning models have been proposed, either a lack of accurate description of local chemical environments or demanding a large number of samples for training has limited their practical applications. In this study, we combine a physically inspired dipole interaction model and an accurate neural network method for predicting the polarizability tensors of molecules. With the local chemical environment precisely described and the requirement of rotational covariance naturally fulfilled, this hybrid model is proven to give an accurate molecular polarizability prediction, essentially reducing the number of training samples. The atomic polarizabilities are physically interpretable and transferable to larger molecules unseen in the training set. This promising method may find its wide range of applications, such as spectroscopic simulations and the construction of polarizable force fields.

PMID:36753749 | DOI:10.1021/acs.jctc.2c01094

J Cardiovasc Med (Hagerstown). 2023 Mar 1;24(3):191-199. doi: 10.2459/JCM.0000000000001446.

ABSTRACT

AIMS: To assess the characteristics of left atrial appendage (LAA) stump and left atrial (LA) volume after standalone totally thoracoscopic LAA exclusion in 40 patients with nonvalvular atrial fibrillation (NVAF) and contraindications to oral anticoagulation (OAC), using cardiac computed tomography (CCT) and transoesophageal echocardiography (TOE).

METHODS: Using CCT and TOE, we evaluated correct AtriClip Pro II positioning, the presence and characteristics of the LAA stump and the postprocedural LA volume, at 3 months’ follow-up. Stump depth was measured with both CCT and TOE using a new method, based on left circumflex artery (LCX) course.

RESULTS: After placement of AtriClip, all 40 patients discontinued OAC, and no stroke occurred. LAA exclusion was achieved in 40/40 patients at 3 months’ follow-up. LAA stump (depth <10 mm in 12/18 stump, 67%) was observed in 18 patients. The overall (LA + LAA) volume and isolated LA volume were statistically different when comparing cases with and without LAA stump (P < 0.02). LAA ostium dimensions (perimeter and area) and LAA volume correlate with stump depth (P < 0.02). There was a high correlation between CCT and TOE in stump identification and depth measurement (P < 0.02). Compared with the baseline, CCT LA volume increased (P < 0.01) at 3 months’ follow-up.

CONCLUSION: Preprocedural and postprocedural CCT and TOE are useful and comparable in patients undergoing standalone totally thoracoscopic exclusion of LAA, because these imaging methods can identify anatomical LAA and LA characteristics predisposing for a postprocedural residual stump.

PMID:36753726 | DOI:10.2459/JCM.0000000000001446