Preservation versus replacement of the aortic root for acute type A aortic dissection

OBJECTIVE

To determine the impact of aortic root preservation versus aortic root replacement (ARR) after acute type A aortic dissection (ATAAD) repair.

METHODS

In this observational study of consecutive aortic surgeries between 2007 and 2021, patients with ATAAD were identified via a prospectively maintained institutional database and were stratified by root preservation versus ARR (including valve-sparing and complete ARR). Kaplan-Meier survival estimation and multivariable Cox regression analysis were performed.

RESULTS

Among the 601 patients underwent aortic arch reconstruction for ATAAD, 370 (61.6%) underwent root preservation and the other 231 (38.4%) underwent ARR, with a median follow-up of 6.3 years (interquartile range, 3.8-9.6 years). Cardiopulmonary bypass and ischemic times were longer in the ARR group, but intraoperative variables were otherwise similar between the groups, including cannulation strategy and extent of distal repair. There were no between-group differences in postoperative outcomes, including operative mortality, stroke, mechanical ventilation time, renal failure, reexploration for bleeding, and total length of stay. At a 1-year follow-up, the incidence of aortic regurgitation (moderate or greater) was similar in the 2 groups. On multivariable Cox regression, ARR was not associated with improved long-term survival compared with root preservation (hazard ratio, 1.13; 95% confidence interval, 0.82-1.56; P = .44). Late reinterventions on the aortic root or valve were similar in the 2 groups and was 2.0% for the overall cohort.

CONCLUSIONS

These findings suggest that aortic root preservation may achieve similar midterm outcomes as ARR after ATAAD repair.

Central versus peripheral cannulation for acute type A aortic dissection

OBJECTIVE

This study sought to evaluate the impact of central aortic versus peripheral cannulation on outcomes after acute type A aortic dissection repair.

METHODS

This was an observational study using an institutional database of acute type A aortic dissection repairs from 2007 to 2021. Patients were stratified according to central, subclavian, or femoral cannulation. Kaplan-Meier survival estimation and multivariable Cox regression were performed.

RESULTS

The study population consisted of 577 patients who underwent acute type A aortic dissection repair. Of these, central cannulation was used in 490 patients (84.9%), subclavian cannulation was used in 54 patients (9.4%), and femoral cannulation was used in 33 patients (5.7%). Rates of peripheral vascular disease, aortic insufficiency moderate or greater, and cerebral malperfusion differed significantly among the groups, but baseline characteristics were otherwise comparable (P > .05). Operative mortality was lowest in the central cannulation group (9.8%), but this did not differ significantly among the groups. Kaplan-Meier survival estimates were similar among the groups. On multivariable Cox regression, cannulation strategy was not significantly associated with long-term survival.

CONCLUSIONS

Acute type A aortic dissection repair can be safely performed through central aortic cannulation, with outcomes comparable to those obtained with subclavian or femoral cannulation.

Transfusion of non-red blood cell blood products does not reduce survival following cardiac surgery

OBJECTIVES

The literature supports the assertion that patients undergoing cardiac surgery who receive perioperative packed red blood cell (pRBC) transfusions have increased associated mortality. The aim of the current study is to assess whether there is an association between non-pRBC blood product transfusions and increased mortality.

METHODS

Data from our center's Society of Thoracic Surgeons database included patients who underwent cardiac surgery from 2010 to 2018. Patients with pRBC transfusions or circulatory arrest were excluded. Propensity matching was performed (1:1; caliper = 0.2 times the standard deviation of logit of propensity score). Kaplan-Meier estimates and Cox regression were used. Cardiac transplant, ventricular assist devices, transcatheter aortic valves, and patients who had experienced circulatory arrest were excluded from this analysis.

RESULTS

A total of 8042 patients met criteria for analysis. Following propensity matching (1:1), 395 patients requiring perioperative non-pRBC blood products (platelets, fresh-frozen plasma, and cryoprecipitate) were matched with 395 nontransfusion patients, yielding equitable patient cohorts. Median follow-up was 4.5 (3.0-6.4) years. Patients received platelets (327 [82.8%]), fresh-frozen plasma (141 [35.7%]), and cryoprecipitate (60 [15.2%]). There was no significant difference in the postoperative mortality (6 [1.5%] vs 4 [1.0%]; P = .52). Reoperation (20 [5.0%] vs 8 [2.0%]; P < .02) and prolonged ventilation (36 [9.1%] vs 19 [4.8%]; P < .02) were greater in the transfusion group. Emergent operation (odds ratio [OR] 2.86 [1.72-4.78]; P < .001), intra-aortic balloon pump (OR 3.24 [1.64-6.39]; P < .001), and multivalve operation (OR 4.34 [2.83-6.67]; P < .001) were significantly associated with blood product use. Blood product transfusion (hazard ratio; 1.15 [0.89-1.48]; P = .3) was not significantly associated with increased mortality risk. There was no significant long-term survival difference between cohorts.

CONCLUSIONS

Patients who undergo cardiac surgery requiring blood products alone, without pRBC transfusion, have similar postoperative and long-term survival compared with patients not requiring blood products. These data are based on a limited patient sample, and future studies will aid in improving the generalizability of these results.

The long-term impact of postoperative atrial fibrillation after cardiac surgery

OBJECTIVE

The literature has reported worse in-hospital outcomes for patients with atrial fibrillation. The objective of the following study is to provide detailed results on the long-term impact of postoperative atrial fibrillation on survival and hospital readmission in cardiac surgery.

METHODS

All patients undergoing open cardiac surgery were reviewed with the exclusion of preoperative atrial fibrillation or patients undergoing ventricular assist device, transplant, or Cox-Maze procedures. Propensity matching (1:1) was performed to ensure similar baseline characteristics. Multivariable analysis identified significant associations with mortality and readmission.

RESULTS

A total of 12,227 patients with cardiac disease were divided into 7927 patients (64.8%) without postoperative atrial fibrillation and 4300 patients (35.2%) with new-onset postoperative atrial fibrillation. Propensity matching (1:1) yielded 4275 risk-adjusted pairs. There was no difference between the nonpostoperative atrial fibrillation versus postoperative atrial fibrillation cohorts regarding operative mortality (4.61% vs 4.12%; P = .26) and stroke (2.32% vs 2.76%; P = .191). Patients with postoperative atrial fibrillation had higher rates of reoperation (12.12% vs 6.83%; P < .001), transfusion (43.42% vs 36.94%; P < .001), sepsis (1.99% vs 0.80%; P < .001), prolonged ventilation (15.88% vs 9.24% vs; P < .001), pneumonia (6.60% vs 2.36%; P < .001), renal failure (6.90% vs 3.37%; P < .001), and dialysis (4.94% vs 2.08%; P < .001). The postoperative atrial fibrillation cohort had a significantly higher incidence of atrial fibrillation on follow-up (11.74% vs 4.75%; P < .001). Postoperative atrial fibrillation was independently associated with mortality (hazard ratio, 1.21; 1.12-1.33; P < .001), all-cause readmissions (hazard ratio, 1.05; 1.01-1.1; P = .010), and heart failure-specific readmission (hazard ratio, 1.14; 1.04-1.26; P = .01).

CONCLUSIONS

Patients in the postoperative atrial fibrillation cohort had worse perioperative morbidity, lower survival, and more readmissions for heart failure on long-term follow-up.

Outcomes of Transcatheter Aortic Valve Replacement in Patients With Concomitant Aortic Regurgitation

BACKGROUND

This study sought to evaluate outcomes of transcatheter aortic valve replacement (TAVR) in patients with moderate or greater aortic regurgitation (AR).

METHODS

This was an observational study using an institutional database of TAVRs from November 2012 to April 2022. The study compared outcomes of TAVR in patients with isolated aortic stenosis (AS) vs patients with AS and concomitant AR (moderate or greater). Those patients with trace or mild AR were excluded. Clinical and echocardiographic outcomes were compared, with end points established by the Valve Academic Research Consortium 3. Kaplan-Meier survival estimation and Cox regression for mortality were performed. Competing-risk cumulative incidence estimates for heart failure readmissions were also compared.

RESULTS

Of 3295 patients, 605 (53.4%) had severe AS with no AR and 529 (46.6%) had severe AS with moderate or severe AR. There were no significant differences in in-hospital mortality, length of stay, stroke, myocardial infarction, permanent pacemaker requirement, transfusion requirement, minor or major vascular complications, or 30-day readmissions between the 2 groups (P > .05). There were also no significant differences in annular dissection or rupture, coronary obstruction, or device embolization. Mean gradient and paravalvular leak rates at 30 days and 1 year were similar between the groups. Survival estimates were comparable, and, on multivariable Cox regression, mixed aortic valvular disease was not associated with an increased hazard of death as compared with isolated AS (hazard ratio, 1.01; 95% CI, 0.81-1.25; P = .962). Cumulative incidence estimates for heart failure readmissions were comparable between groups.

CONCLUSIONS

TAVR can be safely performed in patients with mixed valvular disease, with outcomes comparable to those in isolated AS.

Impact of Hospital Teaching Status in Type A Aortic Dissections: An Analysis of More Than 37 000 Patients

BACKGROUND

The purpose of this study was to assess the effect of a hospital's teaching status on survival and outcomes of patients presenting with type A aortic dissections imperative for enhancing patient care.

METHODS

The National Readmission Database was used to review all type A aortic dissections between 2010 and 2017. Provided sampling weights were used to generate national estimates, and baseline variables were compared with descriptive statistics. Mixed effects and logistic models were created for 30-day and 90-day readmission and inhospital mortality.

RESULTS

In all, 37 396 type A aortic dissections were identified, the majority of which (83%) were operated on at a teaching hospital. Inhospital mortality was higher at nonteaching hospitals A (20.3% vs 14.42%, P < .001). Median hospital charge was higher at teaching hospitals ($59 670 vs $53 220, P < .001). There was a higher rate of 30-day readmission in teaching hospitals (20.95% vs 19.36%, P = .02). On logistic regression for mortality, hospital teaching status was a significant protective factor (odds ratio 0.83, P < .001). On mixed effects logistic regression, hospital teaching status was not significant for readmissions.

CONCLUSIONS

Type A aortic dissections continue to be primarily managed by teaching hospitals, with superior outcomes continuing to come from teaching hospitals. Given the substantial proportion of patients presenting out of state, investigations into optimal patient transfer and postoperative monitoring and referral could improve care.

Nonmonotonous Translocation Time of Polymers across Pores

Polymers confined in corrugated channels, i.e., channels of varying amplitude, display multiple local maxima and minima of the diffusion coefficient upon increasing their degree of polymerization N. We propose a theoretical effective free energy for linear polymers based on a Fick-Jacobs approach. We validate the predictions against numerical data, obtaining quantitative agreement for the effective free energy, the diffusion coefficient, and the mean first passage time. Finally, we employ the effective free energy to compute the polymer lengths N_{min} at which the diffusion coefficient presents a minimum: we find a scaling expression that we rationalize with a blob model. Our results could be useful to design porous adsorbers, that separate polymers of different sizes without the action of an external flow.

Hydrophobic Homopolymer's Coil-Globule Transition and Adsorption onto a Hydrophobic Surface under Different Conditions

Unstructured proteins can modulate cellular responses to environmental conditions by undergoing coil-globule transitions and phase separation. However, the molecular mechanisms of these phenomena still need to be fully understood. Here, we use Monte Carlo calculations of a coarse-grained model incorporating water's effects on the system's free energy. Following previous studies, we modeled an unstructured protein as a polymer chain. Because we are interested in investigating how it responds to thermodynamic changes near a hydrophobic surface under different conditions, we chose an entirely hydrophobic sequence to maximize the interaction with the interface. We show that a slit pore confinement without top-down symmetry enhances the unfolding and adsorption of the chain in both random coil and globular states. Moreover, we demonstrate that the hydration water modulates this behavior depending on the thermodynamic parameters. Our findings provide insights into how homopolymers and possibly unstructured proteins can sense and adjust to external stimuli such as nanointerfaces or stresses.

AI-aided holographic flow cytometry for label-free identification of ovarian cancer cells in the presence of unbalanced datasets

Liquid biopsy is a valuable emerging alternative to tissue biopsy with great potential in the noninvasive early diagnostics of cancer. Liquid biopsy based on single cell analysis can be a powerful approach to identify circulating tumor cells (CTCs) in the bloodstream and could provide new opportunities to be implemented in routine screening programs. Since CTCs are very rare, the accurate classification based on high-throughput and highly informative microscopy methods should minimize the false negative rates. Here, we show that holographic flow cytometry is a valuable instrument to obtain quantitative phase-contrast maps as input data for artificial intelligence (AI)-based classifiers. We tackle the problem of discriminating between A2780 ovarian cancer cells and THP1 monocyte cells based on the phase-contrast images obtained in flow cytometry mode. We compare conventional machine learning analysis and deep learning architectures in the non-ideal case of having a dataset with unbalanced populations for the AI training step. The results show the capacity of AI-aided holographic flow cytometry to discriminate between the two cell lines and highlight the important role played by the phase-contrast signature of the cells to guarantee accurate classification.

Correction: March et al. Protein Unfolding and Aggregation near a Hydrophobic Interface. Polymers 2021, 13, 156

In the original publication [...].

Rheology of Pseudomonas fluorescens biofilms: From experiments to predictive DPD mesoscopic modeling

Bacterial biofilms mechanically behave as viscoelastic media consisting of micron-sized bacteria cross-linked to a self-produced network of extracellular polymeric substances (EPSs) embedded in water. Structural principles for numerical modeling aim at describing mesoscopic viscoelasticity without losing details on the underlying interactions existing in wide regimes of deformation under hydrodynamic stress. Here, we approach the computational challenge to model bacterial biofilms for predictive mechanics in silico under variable stress conditions. Up-to-date models are not entirely satisfactory due to the plethora of parameters required to make them functioning under the effects of stress. As guided by the structural depiction gained in a previous work with Pseudomonas fluorescens [Jara et al., Front. Microbiol. 11, 588884 (2021)], we propose a mechanical modeling by means of Dissipative Particle Dynamics (DPD), which captures the essentials of topological and compositional interactions between bacterial particles and cross-linked EPS-embedding under imposed shear. The P. fluorescens biofilms have been modeled under mechanical stress mimicking shear stresses as undergone in vitro. The predictive capacity for mechanical features in DPD-simulated biofilms has been investigated by varying the externally imposed field of shear strain at variable amplitude and frequency. The parametric map of essential biofilm ingredients has been explored by making the rheological responses to emerge among conservative mesoscopic interactions and frictional dissipation in the underlying microscale. The proposed coarse grained DPD simulation qualitatively catches the rheology of the P. fluorescens biofilm over several decades of dynamic scaling.

The Long-Term Impact of Diastolic Dysfunction After Routine Cardiac Surgery

OBJECTIVE

To determine the impact of diastolic dysfunction (DD) on survival after routine cardiac surgery.

DESIGN

This was an observational study of consecutive cardiac surgeries from 2010 to 2021.

SETTING

At a single institution.

PARTICIPANTS

Patients undergoing isolated coronary, isolated valvular, and concomitant coronary and valvular surgery were included. Patients with a transthoracic echocardiogram (TTE) longer than 6 months prior to their index surgery were excluded from the analysis.

INTERVENTIONS

Patients were categorized via preoperative TTE as having no DD, grade I DD, grade II DD, or grade III DD.

MEASUREMENTS AND MAIN RESULTS

A total of 8,682 patients undergoing a coronary and/or valvular surgery were identified, of whom 4,375 (50.4%) had no DD, 3,034 (34.9%) had grade I DD, 1,066 (12.3%) had grade II DD, and 207 (2.4%) had grade III DD. The median (IQR) time of the TTE prior to the index surgery was 6 (2-29) days. Operative mortality was 5.8% in the grade III DD group v 2.4% for grade II DD, 1.9% for grade I DD, and 2.1% for no DD (p = 0.001). Atrial fibrillation, prolonged mechanical ventilation (>24 hours), acute kidney injury, any packed red blood cell transfusion, reexploration for bleeding, and length of stay were higher in the grade III DD group compared to the rest of the cohort. The median follow-up was 4.0 (IQR: 1.7-6.5) years. Kaplan-Meier survival estimates were lower in the grade III DD group than in the rest of the cohort.

CONCLUSIONS

These findings suggested that DD may be associated with poor short-term and long-term outcomes.

Coronary Artery Bypass With Multiarterial Grafting vs Percutaneous Coronary Intervention

BACKGROUND

Data comparing patients who undergo multiarterial grafting during coronary artery bypass grafting (CABG) vs percutaneous coronary intervention (PCI) in patients with multivessel coronary disease are scarce. This study addresses the relevance of using multiple arterial conduits vs PCI for appropriate patients.

METHODS

This retrospective study included all patients with coronary artery disease who underwent CABG with multiple arterial conduits or PCI. Propensity score matching was performed for baseline characteristics. Kaplan-Meier estimates, cumulative incidence, and freedom from major adverse cardiac and cerebrovascular events (MACCE) curves were performed.

RESULTS

The total patient population consisted of 3648 patients from 2011 to 2018 divided into 902 CABG patients and 2746 PCI patients. Patients were propensity matched (PCI, n = 838; CABG, n = 838). In the CABG cohort the left internal mammary artery was used in 837 patients (99.9%), the right internal mammary artery in 770 patients (92%), and radial arteries in 108 patients (12.9%). Patients in the PCI cohort had significantly higher 30-day mortality (24 [2.9%] vs 7 [0.8%], P < .01). Survival over follow-up (median, 4.9 years; range, 3.3-6.8) was better for the CABG cohort (730 [87.1%] vs 625 [74.6%], P < .01). Patients in the CABG cohort had greater freedom from MACCE (607 [72.4%] vs 339 [40.5%], P < .01). Cox multivariable regression showed that patients who underwent CABG had a significantly reduced risk of mortality (hazard ratio, 0.49; 95% confidence interval, 0.39-0.61; P < .01) and of MACCE (hazard ratio, 0.33; 95% confidence interval, 0.28-0.38; P < .01).

CONCLUSIONS

Patients with coronary artery disease who undergo CABG with multiple arterial conduits have significantly fewer major adverse events, improved survival, and reduced hospital readmissions.

The use of blood and blood products in aortic surgery is associated with adverse outcomes

OBJECTIVE

To report long-term outcomes after deep hypothermic circulatory arrest (DHCA) with or without perioperative blood or blood products.

METHODS

All patients who underwent proximal aortic surgery with DHCA from 2011 to 2018 were propensity matched according to baseline characteristics. Primary outcomes included short- and long-term mortality. Stratified Cox regression analysis was performed for significant associations with survival.

RESULTS

A total of 824 patients underwent aortic replacement requiring circulatory arrest. After matching, there were 224 patients in each arm (transfusion and no transfusion). All baseline characteristics were well matched, with a standardized mean difference (SMD) <0.1. Preoperative hematocrit (41.0 vs 40.6; SMD = 0.05) and ejection fraction (57.5% vs 57.0%; SMD = 0.08) were similar between the no transfusion and blood product transfusion cohorts. Rate of aortic dissection (42.9% vs 45.1%; SMD = 0.05), hemiarch replacement (70.1% vs 70.1%; SMD = 0.00), and total arch replacement (21.9% vs 23.2%; SMD = 0.03) were not statistically different. Cardiopulmonary bypass and cross-clamp time were higher in the blood product transfusion cohort (P < .001). Operative mortality (9.4% vs 2.7%; P = .003), stroke (7.6% vs 1.3%; P = .001), reoperation rate, pneumonia, prolonged ventilation, and dialysis requirements were significantly higher in the transfusion cohort (P < .001). In stratified Cox regression, transfusion was an independent predictor of mortality (hazard ratio, 2.62 [confidence interval, 1.47-4.67]; P = .001). One- and 5-year survival were significantly reduced for the transfusion cohort (P < .001).

CONCLUSIONS

In patients who underwent aortic surgery with DHCA, perioperative transfusions were associated with poor outcomes despite matching for preoperative baseline characteristics.

The impact of prior cardiac surgery on patients undergoing surgical repair for acute type A aortic dissection

OBJECTIVE

To determine the impact of reoperative versus first-time sternotomy for emergent open repair of acute Type A aortic dissection (ATAAD).

METHODS

This was an observational study of consecutive aortic surgeries from 2007 to 2021. Kaplan-Meier survival estimation and multivariable Cox regression analysis were performed to assess the impact of reoperative versus first-time sternotomy upon survival after ATAAD repair.

RESULTS

A total of 601 patients with ATAAD were identified, of which 72 (12%) underwent reoperative sternotomy. The reoperative group had a higher prevalence of baseline comorbidities, including hypertension, diabetes, peripheral vascular disease, atrial fibrillation, and coronary artery disease. Central cannulation of the aorta was achieved at a similar rate across each group (81.9% vs. 81.5%, p = .923), and cardiopulmonary bypass (CPB) time was similar across each group (204 ± 84.8 vs. 203 ± 72.4 min, p = .923). Postoperative outcomes were similar across both groups, including in-hospital mortality, stroke, pulmonary complications, renal failure, and reexploration for excessive bleeding. Five-year survival was 74.5% (70.5, 78.3) for the first-time group and was 71.6% (60.0, 81.9) for the reoperative group. After multivariable Cox regression, reoperative sternotomy was not significantly associated with an increased hazard of death compared to first-time sternotomy (hazards ratio: 0.90, 95% confidence interval: 0.56, 1.43, p = .642).

CONCLUSIONS

These findings suggest that re-sternotomy can be safely performed with similar outcomes as first-time sternotomy. Central initiation of CPB after sternal reentry limits CPB time and may therefore represent a protective strategy that enhances outcomes for patients presenting with ATAAD and prior cardiac surgery.

Sex-based outcomes after surgery for acute type A aortic dissection

BACKGROUND

While prior data have suggested worse outcomes in women after acute type A aortic dissection (ATAAD) repair when compared to men, results have been inconsistent across studies over time. This study sought to evaluate the impact of sex on short- and long-term outcomes after ATAAD repair.

METHODS

This was a retrospective study utilizing an institutional database of ATAAD repairs from 2007 to 2021. Patients were stratified according to sex. Kaplan-Meier survival estimation and multivariable Cox regression were performed. Supplementary analysis using propensity score matching was also performed.

RESULTS

Of the 601 patients who underwent ATAAD repair, 361 were males (60.1%) and 240 (39.9%) were females. Females were significantly older, more likely to have hypertension, and more likely to have chronic lung disease. Females were also significantly more likely than males to undergo hemiarch replacement, while males were significantly more likely than females to undergo total arch replacement and frozen elephant trunk. Operative mortality was 9.4% among males and 13.8% among females, though this was not a statistically significant difference (p = .098). Postoperative complications were comparable between groups. Kaplan-Meier survival estimates were similar for men and women, and, on multivariable Cox regression, sex was not significantly associated with long-term survival (hazard ratio: 1.00, 95% confidence interval: 0.73, 1.37, p = .986). Outcomes remained comparable after supplementary propensity score matched analysis.

CONCLUSION

ATAAD repair can be performed with comparable short-term and long-term outcomes in both men and women.

National trends in thoracic aortic aneurysms and dissections in patients with Marfans and Ehlers Danlos syndrome

INTRODUCTION

Connective tissue disorders predispose patients to earlier aortic dissections and aneurysms. However, there is limited large cohort data given its low incidence.

METHODS

The National Inpatient Sample was searched for all adults with Marfans (MFS) and Ehlers Danlos (EDS) disease between 2010 and 2017. ICD codes were used to select those with a type A aortic dissection or aneurysm.

RESULTS

There was a total of 19,567 cases, giving the estimated incidence of MFS and EDS of 18 and 22.4 per 100k people, respectively. After inclusion criteria, there were 2553 MF and 180 EDS patients. There was no statistical difference in mortality between the MFS and EDS cohorts (4.6% vs. 2.8%, p = .26). EDS patients were more likely to undergo a TEVAR procedure (2.8% vs. 1.0%, p = .03). MF patients were more likely to have a complication of acute kidney injury (p = .02). EDS patients were more likely older (50 vs. 42, p < .001) and female (47% vs. 33%, p < .001). MFS patients were more likely to have a type A aortic dissection (44% vs. 31%, p < .001). The majority (89%) of patients were treated at urban teaching hospitals. On univariable logistic regression, aortic dissection was a predictor for mortality (odds ratio 7.31, p < .001). The type of connective tissue disease was not a significant predictor.

CONCLUSIONS

National level estimates show low mortality for patients with MF or ED presenting to the hospital with aortic dissection or aneurysm. The differences in age and gender can guide surveillance for these patient populations, leading to more elective admissions and reduced hospital mortality.

Key aspects of the past 30 years of protein design

Proteins are the workhorse of life. They are the building infrastructure of living systems; they are the most efficient molecular machines known, and their enzymatic activity is still unmatched in versatility by any artificial system. Perhaps proteins' most remarkable feature is their modularity. The large amount of information required to specify each protein's function is analogically encoded with an alphabet of just ∼20 letters. The protein folding problem is how to encode all such information in a sequence of 20 letters. In this review, we go through the last 30 years of research to summarize the state of the art and highlight some applications related to fundamental problems of protein evolution.

The long-term impact of acute renal failure after aortic arch replacement for acute type A aortic dissection

OBJECTIVE

To determine the long-term impact of developing acute renal failure (ARF) on survival after open aortic arch reconstruction for acute type A aortic dissection (ATAAD).

METHODS

This was an observational study of consecutive aortic surgeries from 2007 to 2021. Patients with ATAAD were identified via a prospectively maintained institutional database and were stratified by the presence or absence of postoperative ARF (by RIFLE criteria). Kaplan-Meier survival estimation and multivariable Cox regression analysis were performed.

RESULTS

A total of 601 patients undergoing open surgery for ATAAD were identified, of which 516 (85.9%) did not develop postoperative ARF, while 85 (14.1%) developed ARF, with a median follow-up time of 4.6 years (1.6, 7.9). Baseline characteristics were similar across each group, except for higher rates of branch vessel malperfusion and lower preoperative ejection fraction in the ARF group. Patients with ARF underwent more total arch replacement and elephant trunk procedures, with longer cardiopulmonary bypass and circulatory arrest times than patients without ARF. ARF was associated with worse short-term outcomes, including increased in-hospital mortality, prolonged mechanical ventilation, higher rates of sepsis, more blood transfusions, and longer length of hospital stay. Unadjusted Kaplan-Meier survival estimates were significantly lower in the ARF group, compared to the group without ARF (p < .001, log-rank test). After multivariable adjustment, the development of postoperative ARF was significantly associated with an increased hazard of death over the study's follow-up time-period (hazard ratio: 2.74, 95% confidence interval: 1.95, 3.86, p < .001).

CONCLUSIONS

ARF is a highly morbid postoperative event that may adversely impact long-term survival after aortic surgery.

A multicentre, open-label, single-arm phase II trial of the efficacy and safety of sclerotherapy using 3% polidocanol foam to treat second-degree haemorrhoids (SCLEROFOAM)

Background

The aim of the present study was to evaluate the efficacy and safety of 3% polidocanol foam for treating 2nd-degree haemorrhoids.

Methods

A multicentre, open-label, single-arm, phase 2 trial involving 10 tertiary referral centres for haemorrhodal disease (HD) was performed. Between January and June 2019, patients with 2nd-degree haemorrhoids were prospectively included in this study. The primary outcome was to establish the success rate after one sclerotherapy session in terms of complete resolution of bleeding episodes one week after the injection. The Hemorrhoidal Disease Symptom Score (HDSS), the Short Health Scale for HD (SHS-HD) score and the Vaizey incontinence score were used to assess symptoms and their impact on quality of life and continence. Pain after the procedure, subjective symptoms and the amount and type of painkillers used were recorded. Patients were followed up for 1 year.

Results

There were 183 patients [111 males; 60.7%, mean age 51.3 ± 13.5 (18–75) years]. Complete resolution of bleeding was reached in 125/183 patients (68.3%) at 1 week and the recurrence rate was 12% (15/125).

Thirteen patients (7.4%) underwent a second sclerotherapy session, while only 1 patient (1.8%) had to undergo a third session. The overall 1-year success rate was 95.6% (175/183). The HDSS and the SHS score significantly improved from a median preoperative value of 11 and 18 to 0 and 0, respectively (p < 0.001). There were 3 episodes of external thrombosis. No serious adverse events occurred.

Conclusions

Sclerotherapy with 3% polidocanol foam is a safe, effective, painless, repeatable and low-cost procedure in patients with bleeding haemorrhoids.

A machine learning approach to model for end-stage liver disease score in cardiac surgery

OBJECTIVE

Model for end-stage liver disease (MELD) likely has nonlinear effects on operative outcomes. We use machine learning to evaluate the nonlinear (dependent variable may not correlate one to one with an increased risk in the outcome) relationship between MELD and outcomes of cardiac surgery.

METHODS

Society of Thoracic Surgery indexed elective cardiac operations between 2011 and 2018 were included. MELD was retrospectively calculated. Logistic regression models and an imbalanced random forest classifier were created on operative mortality. Cox regression models and random forest survival models evaluated survival. Variable importance analysis (VIMP) ranked variables by predictive power. Linear and machine-learned models were compared with receiver operator characteristic (ROC) and Brier score.

RESULTS

We included 3872 patients. Operative mortality was 1.7% and 5-year survival was 82.1%. MELD was the fourth largest positive predictor on VIMP analysis for operative long-term survival and the strongest negative predictor for operative mortality. MELD was not a significant predictor for operative mortality or long-term survival in the logistic or Cox regressions. The logistic model ROC area was 0.762, compared to the random forest classifier ROC of 0.674. The Brier score of the random forest survival model was larger than the Cox regression starting at 2 years and continuing throughout the study period. Bootstrap estimation on linear regression demonstrated machine-learned models were superior.

CONCLUSIONS

MELD and mortality are nonlinear. MELD was insignificant in the Cox multivariable regression but was strongly important in the random forest survival model and when using bootstrapping, the superior utility was demonstrated of the machine-learned models.

Mild hypothermia versus normothermia in patients undergoing cardiac surgery

Objective

Temperature during cardiopulmonary bypass (CPB) for cardiac surgery has been controversial. The aim of the current study is to compare the outcomes for patients with mild hypothermia versus normothermic CPB temperatures.

Methods

All patients who underwent cardiac surgery with CPB and temperatures ≥32°C from 2011 to 2018 were included, which consisted of mild hypothermia (32°C-35°C) and normothermia (>35°C) cohorts. Propensity matching (1:1) was performed for risk adjustment. Primary outcomes included operative and long-term survival. Secondary outcomes included postoperative complications.

Results

A total of 6525 patients comprised 2 cohorts: mild hypothermia (32°C-35°C; n = 3148) versus normothermia (>35°C; n = 3377). Following adjustment for surgeon preference, there were 1601 propensity-matched patients who had similar baseline characteristics (standard mean difference, ≤0.10), including CPB time, crossclamp time, and intra-aortic balloon pump placement. Kaplan-Meier analysis showed no difference in long-term survival (82.6% vs 81.6%; P = .81). Over a median follow-up of 4.4 years, there were no differences in overall mortality (18.1% vs 18.1%; P = 1.1) or readmission (50.3% vs 48.3%; P = .2). Acute renal failure (3.7% vs 2.4%; P = .03) and intensive care unit hours (46.5 vs 45.1; P = .04) were significantly higher with hypothermia. There was no difference between cohorts for postoperative stroke (2.0% vs 2.0%; P = 1.0), reoperation (5.9% vs 6.0%; P = .9), or operative intra-aortic balloon pump placement (1.7% vs 1.8%; P = .9).

Conclusions

Patients with mild hypothermia during CPB had increased postoperative renal failure and length of intensive care unit stay. Although there was no difference in long-term survival, mild hypothermia does not appear to offer patients appreciable benefits, compared with normothermia.

Cardiac surgery in the afternoon is not associated with increased operative morbidity and mortality

BACKGROUND

Time of day for surgical procedures has been a topic of considerable controversy, with some suggesting that later operating times are associated with worse outcomes.

METHODS

All patients who underwent open cardiac surgery from 2011 to 2018 were included. Patients that had ventricular assist devices, heart transplant, transcatheter aortic valves, aortic dissections, and emergent operations were excluded. Primary outcomes included postoperative mortality and survival; secondary outcomes included postoperative complications and readmission.

RESULTS

The initial patient population consisted of 7883 patients who underwent index cardiac surgery. Following propensity matching (3:1), there were 2569 patients in the a.m. cohort (7-11 a.m.) and 860 patients in the p.m. cohort (3-11 p.m.). All baseline characteristics were matched to equivalent proportions. Total intensive care unit time following surgery was longer for the a.m. cohort (46.5 vs. 40.0 h; p<.001). Otherwise, there was no significant difference between cohorts including operative mortality (1.83% vs 2.21%; p= .48). On multivariable analysis, p.m. surgery was not significantly associated with 30 days mortality (hazard ratio [HR]: 0.96 [0.60, 1.53]; p= .86] or mortality over the study follow-up (HR: 0.87 [0.73, 1.03]; p= .10]. For propensity-matched cohorts, Kaplan-Meier survival at 30 days (97.9% vs. 97.4%; p= .44), 1 (93.4% vs  93.9%; p= .51), and 5 years (80.9% vs. 80.2%; p= .84) was not significantly different between cohorts.

CONCLUSION

Short- and long-term mortality, hospital readmission, and postoperative complications were not significantly different between patients that underwent cardiac surgery starting in the a.m. versus patients who had cases that started in the afternoon.

Long-term outcomes of hemiarch replacement with hypothermic circulatory arrest and retrograde cerebral perfusion

OBJECTIVE

This study sought to report outcomes of hemiarch replacement with hypothermic circulatory arrest and retrograde cerebral perfusion, and secondarily, to report outcomes of this operative approach by type of underlying aortic disease.

METHODS

This was an observational study of aortic surgeries from 2010 to 2018. All patients who underwent hemiarch replacement with retrograde cerebral perfusion were included, whereas patients undergoing partial or total arch replacement or concomitant elephant trunk procedures were excluded. Patients were dichotomized into 2 groups by underlying aortic disease; that is, acute aortic dissection (AAD) or aneurysmal degeneration of the aorta. These groups were analyzed for differences in short-term postoperative outcomes, including stroke and operative mortality (Society of Thoracic Surgeons definition). Multivariable Cox analysis was performed to identify variables associated with long-term survival after hemiarch replacement.

RESULTS

A total of 500 patients undergoing hemiarch replacement with hypothermic circulatory arrest plus retrograde cerebral perfusion were identified, of whom 53.0% had aneurysmal disease and 47.0% had AAD. For the entire cohort, operative mortality was 6.4%, whereas stroke occurred in 4.6% of patients. Comparing AAD with aneurysm, operative mortality and stroke rates were similar across each group. Five-year survival was 84.4% ± 0.02% for the entire hemiarch cohort, whereas 5-year survival was 88.0% ± 0.02% for the aneurysm subgroup and was 80.5% ± 0.03% for the AAD subgroup. On multivariable analysis, AAD was not associated with an increased hazard of death, compared with aneurysm (P = .790).

CONCLUSIONS

Morbidity and mortality after hemiarch replacement with hypothermic circulatory arrest plus retrograde cerebral perfusion are acceptably low, and this operative approach may be as advantageous for AAD as it is for aneurysm.

The use of free versus in situ right internal mammary artery in coronary artery bypass grafting

INTRODUCTION

Coronary artery bypass grafting (CABG) continues to be the most commonly performed cardiac surgical procedure in the world. The use of multiarterial grafting may confer a long-term survival benefit over the use of vein grafts. However, there is a paucity of data comparing the use of in situ versus free right internal mammary artery (RIMA) in isolated CABG.

METHODS

Patients that underwent isolated CABG between 2010 and 2018 where RIMA was used in addition to a left internal mammary artery graft. Patients with prior cardiac surgery or percutaneous coronary intervention were excluded. Propensity matching was used for subanalysis. Mortality and major adverse cardiac and cerebrovascular events (MACCE) were analyzed with Kaplan-Meier survival curves and Cox multivariable regression. Heart failure-specific readmissions were assessed with cumulative incidence curves with Fine and Gray competing risk regression.

RESULTS

A total of 667 patients underwent isolated CABG. Of those, 422 had free RIMA and 245 had in situ RIMA utilized. Mortality was similar between cohorts (p = 0.199) with 5-year mortality rates of 6.6% (free) and 4.1% (in situ). MACCE was similar between cohorts, with 5-year event rates of 33.6% and 33.9% (p = 0.99). RIMA style was not a significant predictor of any outcome.

CONCLUSION

There was no difference in long-term mortality, complications, MACCE, or heart failure readmissions when comparing a contemporary cohort of patients undergoing isolated CABG utilizing RIMA as a conduit. These data may allow surgeons to consider using RIMA either as an in situ or a free conduit.

Complete revascularization during coronary artery bypass grafting is associated with reduced major adverse events

OBJECTIVE

Complete revascularization literature is limited by variance in patient cohorts and inconsistent definitions. The objective of the current study was to provide risk-adjusted outcomes for complete revascularization of significant nonmain-branch and main-branch vessel stenoses.

METHODS

All patients that underwent first-time isolated coronary artery bypass grafting procedures were included. Kaplan-Meier survival estimates, cumulative incidence function, and Cox regression were used to analyze outcomes.

RESULTS

The total population consisted of 3356 patients that underwent first-time isolated coronary artery bypass grafting. Eight hundred eighty-nine (26.5%) patients had incomplete and 2467 (73.5%) had complete revascularization. For main-branch vessels, 677 (20.2%) patients had incomplete revascularization and 2679 (79.8%) were completely revascularized. Following risk adjustment with inverse probability treatment weighting, all baseline characteristics were balanced (standardized mean difference, ≤ 0.10). On Kaplan-Meier estimates, survival at 1 year (94.6% vs 92.5%) and 5 years (86.5% vs 82.1%) (P = .05) was significantly better for patients who received complete revascularization. Freedom from major adverse cardiac and cerebrovascular events was significantly higher for the complete revascularization cohort at both 1 year (89.2% vs 84.2%) and 5 years (72.5% vs 66.7%) (P < .001). Complete revascularization (hazard ratio, 0.82; 95% confidence interval, 0.70-0.95; P = .01) was independently associated with a significant reduction in major adverse cardiac and cerebrovascular events. Incomplete revascularization of nonmain-branch vessels was not associated with mortality (hazard ratio, 1.14; 95% confidence interval, 0.74-1.8; P = .55) or major adverse cardiac and cerebrovascular events (hazard ratio, 0.90; 95% confidence interval, 0.66-1.24; P = .52).

CONCLUSIONS

Complete surgical revascularization of all angiographically stenotic vessels in patients with multivessel coronary artery disease is associated with fewer major adverse events. Incomplete revascularization of nonmain-branch vessels is not associated with survival or major adverse cardiac and cerebrovascular events.

Activity-Induced Collapse and Arrest of Active Polymer Rings

We investigate, using numerical simulations, the conformations of isolated active ring polymers. We find that their behavior depends crucially on their size: Short rings (N≲100) swell, whereas longer rings (N≳200) collapse, at sufficiently high activity. By investigating the nonequilibrium process leading to the steady state, we find a universal route driving both outcomes; we highlight the central role of steric interactions, at variance with linear chains, and of topology conservation. We further show that the collapsed rings are arrested by looking at different observables, all underlining the presence of an extremely long timescales at the steady state, associated with the internal dynamics of the collapsed section. Finally, we found that in some circumstances the collapsed state spins about its axis.

Impact of Thoracic Radiation on Patients Undergoing Cardiac Surgery

Prior thoracic radiation has been associated with worse outcomes after cardiac surgery. This study sought to report long-term outcomes in patients undergoing surgery for radiation-associated heart disease. This was an observational study of open cardiac surgeries from 2011 and 2018. Patients with a history of malignancy that required thoracic radiation were identified, and this cohort was matched against a non-irradiated comparison group via Mahalanobis distance matching. Kaplan-Meier survival estimation and multivariable Cox regression analysis was performed to assess the long-term impact of thoracic radiation in patients undergoing cardiac surgery. Of the 15,284 patients receiving cardiac surgery in this time-frame, 269 were identified with a history of thoracic radiation for prior malignancy. Patients with prior radiation had increased 1-year and 5-year mortality (P < 0.001), despite no difference for 30-day mortality (P = 0.719), compared to non-irradiated patients. Mahalanobis distance matching yielded 269 equitably matched pairs. On multivariable analysis, patients with prior radiation demonstrated significantly increased hazard of death, as compared to the non-irradiated group (hazard ratio 1.40, 95% confidence interval: 1.02, 1.94, P = 0.038). Patients with radiation for breast cancer demonstrated a non-significant trend toward reduced hazard of death, as compared to patients with more extensive radiation exposure. There was an increase in long-term mortality in patients with prior radiation undergoing cardiac surgery, however open cardiac surgery can safely be performed in these patients with similar operative mortality. These findings may serve as a useful adjunct in shared decision-making for patients and surgeons alike.

Thirty-day Hospital Readmissions Following Cardiac Surgery are Associated With Mortality and Subsequent Readmission

The aim of the current study was to assess the impact of hospital readmissions within 30-days of discharge, on long-term postoperative outcomes. All patients who underwent cardiac surgery from 2011 - 2018 were included. Patients who had transcatheter procedures, VAD, and transplant were excluded. Inverse probability of treatment weighting (IPTW) propensity scoring was used for population risk adjustment. Multivariable analysis was performed to identify association with long-term mortality and readmission. The total risk adjusted (propensity scoring with IPTW) patient population consisted of 14,538 patients divided into those who were not readmitted in 30-days (nonreadmitted) (n = 12,627) and patients who were readmitted within 30-days (30-day readmitted) (n = 1911). Following IPTW, all baseline characteristics and postoperative complications were equivalent between cohorts (SMD <0.10). Patients who required intraoperative [OR 1.178 (1.05, 1.32); P = 0.006] and postoperative [1.32 (1.18, 1.48); P < 0.001] blood transfusions were at greater risk for 30-day readmission. Median follow-up period was 4.19 years (2.45 - 6.10). The 30-day readmission cohort had a significantly higher mortality risk during early (6 months) follow-up [HR 2.49 (2.01-3.10); P < 0.001] and late (60 months) follow-up [HR 1.30 (1.16-1.47); P < 0.001]. After risk adjustment, the 30-day readmission cohort was significantly associated with increased mortality over the study follow-up period [HR 1.62 (1.48, 1.78); P < 0.001]. 30-day readmissions were an independent predictor of subsequent long-term hospital readmission [HR 1.61 (1.50, 1.73); P < 0.001]. Patients who require 30-day readmissions following cardiac surgery are at increased risk of long-term mortality and repeat readmissions. Early postoperative hospital readmission may be a marker for worse long-term outcomes in cardiac surgery.

The impact of pulmonary artery catheter use in cardiac surgery

OBJECTIVE

Pulmonary artery catheterization provides continuous monitoring of hemodynamic parameters that may aid in the perioperative management of patients undergoing cardiac surgery. However, prior data suggest that pulmonary artery catheterization has limited benefit in intensive care and surgical settings. Thus, this study sought to determine the impact of pulmonary artery catheter insertion on short-term postoperative outcomes in a large, contemporaneous cohort of patients undergoing open cardiac surgery compared with standard central venous pressure monitoring.

METHODS

This was an observational study of open cardiac surgeries from 2010 to 2018. Patients with pulmonary artery catheter insertion were identified and matched against patients without pulmonary artery catheter insertion via 1:1 nearest neighbor propensity matching. Multivariable analysis was performed to assess the impact of pulmonary artery catheterization on operative mortality in the overall cohort, as well as recent heart failure, mitral valve disease, and tricuspid insufficiency subgroups.

RESULTS

Of the 11,820 patients undergoing (Society of Thoracic Surgeons indexed) coronary or valvular surgery, 4605 (39.0%) had pulmonary artery catheter insertion. Propensity score matching yielded 3519 evenly balanced pairs. Compared with central venous pressure monitoring, pulmonary artery catheter use was not associated with improved operative mortality in the overall cohort or in the recent heart failure, mitral valve disease, or tricuspid insufficiency subgroups. Intensive care unit length of stay was longer (P < .001), and there were more packed red blood cell transfusions in the pulmonary artery catheterization group (P < .001); however, postoperative outcomes were otherwise similar, including stroke, sepsis, and new renal failure (P > .05).

CONCLUSIONS

These findings suggest that pulmonary artery catheterization may have limited benefit in cardiac surgery.

Self-Adaptation of Pseudomonas fluorescens Biofilms to Hydrodynamic Stress

In some conditions, bacteria self-organize into biofilms, supracellular structures made of a self-produced embedding matrix, mainly composed of polysaccharides, DNA, proteins, and lipids. It is known that bacteria change their colony/matrix ratio in the presence of external stimuli such as hydrodynamic stress. However, little is still known about the molecular mechanisms driving this self-adaptation. In this work, we monitor structural features of Pseudomonas fluorescens biofilms grown with and without hydrodynamic stress. Our measurements show that the hydrodynamic stress concomitantly increases the cell density population and the matrix production. At short growth timescales, the matrix mediates a weak cell-cell attractive interaction due to the depletion forces originated by the polymer constituents. Using a population dynamics model, we conclude that hydrodynamic stress causes a faster diffusion of nutrients and a higher incorporation of planktonic bacteria to the already formed microcolonies. This results in the formation of more mechanically stable biofilms due to an increase of the number of crosslinks, as shown by computer simulations. The mechanical stability also relies on a change in the chemical compositions of the matrix, which becomes enriched in carbohydrates, known to display adhering properties. Overall, we demonstrate that bacteria are capable of self-adapting to hostile hydrodynamic stress by tailoring the biofilm chemical composition, thus affecting both the mesoscale structure of the matrix and its viscoelastic properties that ultimately regulate the bacteria-polymer interactions.

Anomalous Behavior in the Nucleation of Ice at Negative Pressures

Ice nucleation is a phenomenon that, despite the relevant implications for life, atmospheric sciences, and technological applications, is far from being completely understood, especially under extreme thermodynamic conditions. In this work we present a computational investigation of the homogeneous ice nucleation at negative pressures. By means of the seeding technique we estimate the size of the ice critical nucleus N_{c} for the TIP4P/Ice water model. This is done along the isotherms 230, 240, and 250 K, from positive to negative pressures until reaching the liquid-gas kinetic stability limit (where cavitation cannot be avoided). We find that N_{c} is nonmonotonic upon depressurization, reaching a minimum at negative pressures in the doubly metastable region of water. According to classical nucleation theory we establish the nucleation rate J and the surface tension γ, revealing a retracing behavior of both when the liquid-gas kinetic stability limit is approached. We also predict a reentrant behavior of the homogeneous nucleation line. The reentrance of these properties is related to the reentrance of the coexistence line at negative pressure, revealing new anomalies of water. The results of this work suggest the possibility of having metastable samples of liquid water for long times at negative pressure provided that heterogeneous nucleation is suppressed.

Protein Unfolding and Aggregation near a Hydrophobic Interface

The behavior of proteins near interfaces is relevant for biological and medical purposes. Previous results in bulk show that, when the protein concentration increases, the proteins unfold and, at higher concentrations, aggregate. Here, we study how the presence of a hydrophobic surface affects this course of events. To this goal, we use a coarse-grained model of proteins and study by simulations their folding and aggregation near an ideal hydrophobic surface in an aqueous environment by changing parameters such as temperature and hydrophobic strength, related, e.g., to ions concentration. We show that the hydrophobic surface, as well as the other parameters, affect both the protein unfolding and aggregation. We discuss the interpretation of these results and define future lines for further analysis, with their possible implications in neurodegenerative diseases.

The Impact of the Cox-Maze Technique on Freedom From Atrial Fibrillation

BACKGROUND

Atrial fibrillation (AF) is the most common arrhythmia observed with concomitant cardiac surgery. Surgical options include a cut-and-sew technique Maze (CAS) and a cryoablation/bipolar technique Maze (CB). There are limited data comparing the long-term outcomes of these 2 techniques.

METHODS

All patients who underwent either CAS or CB Maze between 2011 and 2018 were included in the study. Chi-square test and Fisher's exact test or Student's t test were used to compare differences between baseline characteristics. Kaplan-Meier survival curves were generated for each group. Cumulative incidence functions were generated for AF recurrence and Fine-Gray competing-risk regression was used to determine predictors for AF recurrence.

RESULTS

A total of 482 patients underwent open surgical ablation. Of those, 287 had CAS and 198 had CB. All procedures were concomitant with cardiac surgery. There was similar long-term mortality between the CAS and CB cohorts (22.3% vs 17.4%; log-rank P = .91). There was no difference in pacemaker implantation (11.1% vs 11.3%; P = .813) or long-term freedom from AF recurrence (73.3% vs 78.2%; P = .294). On Fine-Gray competing-risk regression, New York Heart Association functional class IV (hazard ratio [HR], 2.07; P = .03), concomitant aortic valve replacement (HR, 3.02; P = .01), and concomitant CABG + valve (HR, 2.36; P = .02) were significant independent predictors for AF recurrence; Maze type was not a predictor.

CONCLUSIONS

These data indicate no difference between the CAS vs CB with respect to freedom from long-term AF. Both techniques may be appropriate based on surgeon experience and patient characteristics.

Outcomes With Heparin-Induced Thrombocytopenia After Cardiac Surgery

BACKGROUND

Heparin-induced thrombocytopenia (HIT) is an immune-mediated reaction to heparin that provokes a prothrombotic state and causes a decline in platelet count. Data describing outcomes of HIT after cardiac surgery are limited. This study sought to determine the impact of HIT on short-term outcomes after cardiac surgery.

METHODS

This was an observational study of cardiac surgeries from 2010 to 2018. Patients with HIT were matched against patients without HIT using 2:1 nearest-neighbor propensity matching. Matching was performed to assess the impact of HIT on operative mortality (The Society of Thoracic Surgeons definition) and thromboembolic events (including deep vein thrombosis, pulmonary embolism, stroke, and/or acute limb ischemia), which were the primary outcomes of interest.

RESULTS

Of 11,820 patients undergoing a Society of Thoracic Surgeons indexed cardiac surgery, 131 (1.1%) developed HIT after their index operation. After matching operative mortality was 21.8% in HIT patients compared with 5.3% in non-HIT patients. Thromboembolic events occurred in 29.1% of HIT patients compared with 2.9% in non-HIT patients. On subanalysis operative mortality was significantly higher for the HIT group without thromboembolic events (16.7%) and the HIT group with thromboembolic events (34.4%) compared with the non-HIT group (5.3%). However operative mortality was not significantly higher in the HIT group with thromboembolic events compared with the HIT group without thromboembolic events, after Bonferroni correction.

CONCLUSIONS

Although uncommon, HIT is a highly morbid and potentially lethal complication, which should reinforce the importance of timely recognition and treatment of this adverse outcome.

Outcomes of Carotid Artery Replacement With Total Arch Reconstruction for Type A Aortic Dissection

BACKGROUND

Cerebral malperfusion and carotid artery dissection in patients with acute type A aortic dissections (TAAD) carry high morbidity and mortality. There are limited data on outcomes of concomitant carotid artery replacement with total arch replacement in the setting of TAAD.

METHODS

All patients with acute TAAD who underwent a total arch replacement between 2007 and 2018 were included. Data were retrospectively collected from a prospectively maintained database. Baselines variables were compared, and Kaplan-Meier estimates were used for long-term survival. Cox multivariable regression analysis was used to identify predictors of mortality.

RESULTS

A total of 161 patients underwent total arch replacement for acute TAAD. Of these, 111 underwent conventional total arch reconstruction, and 50 had a concomitant carotid artery replacement. Baseline characteristics were similar between both cohorts apart from the carotid replacement cohort having a higher rate of preoperative cerebral malperfusion (48% vs 10.81%, P < .01) and preoperative stroke (28% vs 11.71%, P = .02). There was no difference in (operative) 30-day mortality between the carotid replacement and conventional total arch replacement groups (22% vs 18.9%, P = .81), 1-year mortality (28% vs 27.9%, P = .99), or 5-year mortality (32% vs 29.7%, P = .917). Postoperative stroke was 0% vs 4.5% (P = .301) for the carotid vs conventional total arch replacement cohort.

CONCLUSIONS

Concomitant carotid artery replacement is a feasible and safe technique to address perioperative cerebral malperfusion, carotid dissection, and neurologic dysfunction associated with carotid artery dissection, with no difference in long-term survival or postoperative stroke when compared with conventional total arch replacement.