Overview and Clinical Applications of Artificial Intelligence and Machine Learning in Cardiac Anesthesiology.

Artificial intelligence- (AI) and machine learning (ML)-based applications are becoming increasingly pervasive in the healthcare setting. This has in turn challenged clinicians, hospital administrators, and health policymakers to understand such technologies and develop frameworks for safe and sustained clinical implementation. Within cardiac anesthesiology, challenges and opportunities for AI/ML to support patient care are presented by the vast amounts of electronic health data, which are collected rapidly, interpreted, and acted upon within the periprocedural area. To address such challenges and opportunities, in this article, the authors review 3 recent applications relevant to cardiac anesthesiology, including depth of anesthesia monitoring, operating room resource optimization, and transthoracic/transesophageal echocardiography, as conceptual examples to explore strengths and limitations of AI/ML within healthcare, and characterize this evolving landscape. Through reviewing such applications, the authors introduce basic AI/ML concepts and methodologies, as well as practical considerations and ethical concerns for initiating and maintaining safe clinical implementation of AI/ML-based algorithms for cardiac anesthesia patient care.

Impact of minimally invasive lung transplantation on early outcomes and analgesia use: A matched cohort study.

BACKGROUND: Minimally invasive (MI) approaches to lung transplantation (LTx) offer the prospect of faster recovery compared to traditional incisions, however, little data exist describing the impact of surgical technique on early outcomes and analgesia use. METHODS: A prospectively maintained institutional registry identified 170 patients who underwent LTx between January, 2017 and June, 2022. Post-COVID acute respiratory distress syndrome, repeat, and multiorgan transplants were excluded (n = 27) leaving 37 MILTx and 106 traditional LTx patients. Propensity score matching by age, sex, body mass index, diagnosis, lung allocation score, double vs. single lung, hypertension, diabetes, and hospitalization status created 37 pairs. RESULTS: Before matching, MILTx patients were more often male (70% vs 43%) and more likely to receive grafts from younger (31 vs 42 years), circulatory death donors (19% vs 6%) compared with traditional LTx patients (all p < 0.05). After matching, there were no differences in graft warm ischemia or operative duration (both p > 0.05). Postoperatively, MILTx experienced shorter intensive care unit (ICU) (4.3 [IQR 3.1-5.5] vs 8.2 [IQR 3.7-10.8] days) and hospital lengths of stay (LOS) (13 [IQR 11-15] vs 17 [IQR 12-25] days) (both p < 0.05). Among patients surviving to discharge, MILTx patients required fewer opioid prescriptions at discharge (38% vs 66%, p = 0.008) and had improved pulmonary function at 3 months (Forced expiratory volume in 1 second 82 [IQR 72-102] vs 77 [IQR 52-88]% predicted; forced vital capacity 78 [IQR 65-92] vs 70 [IQR 62-80]% predicted] (both p < 0.05). CONCLUSION: Minimally invasive LTx techniques demonstrate potential advantages over traditional approaches, including reduced ICU and hospital LOS, lower opioid use on discharge, and improved early pulmonary function.

Deep learning for transesophageal echocardiography view classification.

Transesophageal echocardiography (TEE) imaging is a vital tool used in the evaluation of complex cardiac pathology and the management of cardiac surgery patients. A key limitation to the application of deep learning strategies to intraoperative and intraprocedural TEE data is the complexity and unstructured nature of these images. In the present study, we developed a deep learning-based, multi-category TEE view classification model that can be used to add structure to intraoperative and intraprocedural TEE imaging data. More specifically, we trained a convolutional neural network (CNN) to predict standardized TEE views using labeled intraoperative and intraprocedural TEE videos from Cedars-Sinai Medical Center (CSMC). We externally validated our model on intraoperative TEE videos from Stanford University Medical Center (SUMC). Accuracy of our model was high across all labeled views. The highest performance was achieved for the Trans-Gastric Left Ventricular Short Axis View (area under the receiver operating curve [AUC] = 0.971 at CSMC, 0.957 at SUMC), the Mid-Esophageal Long Axis View (AUC = 0.954 at CSMC, 0.905 at SUMC), the Mid-Esophageal Aortic Valve Short Axis View (AUC = 0.946 at CSMC, 0.898 at SUMC), and the Mid-Esophageal 4-Chamber View (AUC = 0.939 at CSMC, 0.902 at SUMC). Ultimately, we demonstrate that our deep learning model can accurately classify standardized TEE views, which will facilitate further downstream deep learning analyses for intraoperative and intraprocedural TEE imaging.

Racial Disparities in Failure to Rescue after Pediatric Heart Surgeries in the US.

OBJECTIVE: To identify the trend in failure to rescue (FTR) and risk factors contributing to racial disparities in FTR after pediatric heart surgery using contemporary nationwide data. STUDY DESIGN: We identified 85 267 congenital heart surgeries in patients <18 years of age from 2009 to 2019 using the Kid's Inpatient Database. The primary outcome was FTR. A mixed-effect logistic regression model with hospital random intercept was used to identify independent predictors of FTR. RESULTS: Among 36 753 surgeries with postoperative complications, the FTR was 7.3%. The FTR decreased from 7.4% in 2009 to 6.3% in 2019 (P = .02). FTR was higher among Black than White children for all years. The FTR was higher among girls (7.2%) vs boys (6.6%), children aged <1 (9.6%) vs 12-17 years (2.4%), and those of Black (8.5%) vs White race (5.9%) (all P < .05). Black race was associated with a higher FTR odds (OR, 1.40; 95% CI, 1.20-1.65) after adjusting for demographics, medical complexity, nonelective admission, and hospital surgical volume. Higher hospital volume was associated with a lower odds of FTR for all racial groups, but fewer Black (19.7%) vs White (31%) children underwent surgery at high surgical volume hospitals (P < .001). If Black children were operated on in the same hospitals as White children, the racial differences in FTR would decrease by 47.3%. CONCLUSIONS: Racial disparities exist in FTR after pediatric heart surgery in the US. The racial differences in the location of care may account for almost half the disparities in FTR.

Bicuspid aortic stenosis: National three-year outcomes of transcatheter versus surgical aortic valve replacement among Medicare beneficiaries.

OBJECTIVE: Randomized trials of transcatheter versus surgical aortic valve replacements have excluded bicuspid anatomy. We compared 3-year outcomes of transcatheter aortic valve replacement versus surgical aortic valve replacement in patients aged more than 65 years with bicuspid aortic stenosis. METHODS: The Centers for Medicare and Medicaid data were used to identify 6450 patients undergoing isolated surgical aortic valve replacement (n = 3771) or transcatheter aortic valve replacement (n = 2679) for bicuspid aortic stenosis (2012-2019). Propensity score matching with 21 baseline characteristics including frailty created 797 pairs. RESULTS: Unmatched patients undergoing transcatheter aortic valve replacement were older than patients undergoing surgical aortic valve replacement (78 vs 70 years), with more comorbidities and frailty (all P < .001). After matching, transcatheter aortic valve replacement was associated with a similar mortality risk compared with surgical aortic valve replacement within the first 6 months (hazard ratio [HR], 1.08, 95% CI, 0.67-1.69) but a higher mortality risk between 6 months and 3 years (HR, 2.16, 95% CI, 1.22-3.83). Additionally, transcatheter aortic valve replacement was associated with a lower risk of heart failure readmissions before 6 months (HR, 0.51, 95% CI, 0.31-0.87) but a higher risk between 6 months and 3 years (HR, 4.78, 95% CI, 2.21-10.36). The 3-year risks of aortic valve reintervention (HR, 1.03, 95% CI, 0.30-3.56) and stroke (HR, 1.21, 95% CI, 0.75-1.96) were similar. CONCLUSIONS: Among matched Medicare beneficiaries undergoing transcatheter aortic valve replacement or surgical aortic valve replacement for bicuspid aortic stenosis, 3-year mortality was higher after transcatheter aortic valve replacement. However, transcatheter aortic valve replacement was associated with a similar risk of mortality and a lower risk of heart failure readmissions during the first 6 months after the intervention. Randomized comparative data are needed to best inform treatment choice.

Impact of donor-recipient age-difference in adolescent heart transplantation.

INTRODUCTION: The relationship between donor age and adolescent heart transplant outcomes remains incompletely understood. We aimed to explore the effect of donor-recipient age difference on survival after adolescent heart transplantation. METHODS: The United Network for Organ Sharing database was used to identify 2,855 adolescents aged 10-17 years undergoing isolated primary heart transplantation from 1/1/2000 to 12/31/2022. The primary outcome was 10-year post-transplant survival. Multivariable Cox regression identified predictors of mortality after adjusting for donor and recipient characteristics. A restricted cubic spline assessed the non-linear association between donor-recipient age-difference and the adjusted relative mortality hazard. RESULTS: The median donor-recipient age-difference was +3 (range -13 to +47) years, and 17.7% (n = 504) of recipients had an age- difference > 10 years. Recipients with an age-difference > 10 years had a less favorable pre-transplant profile, including a higher incidence of priority status 1A (81.6%, n = 411 vs. 73.6%, n = 1730; p = .01). The 10-year survival rate was 54.6% (95% confidence interval (CI) 48.8- 60.4) among recipients with a donor-recipient age-difference > 10 years and 66.9% (95% CI: 64.4-69.4) among those with an age-difference ≤10 years. An age-difference > 10 years was an independent predictor of mortality (hazard ratio 1.43, 95% CI: 1.18-1.72, p < .001). Spline analysis demonstrated that the adjusted mortality hazard increased with increasingly positive donor-recipient age-difference and became significantly higher at an age-difference of 11 years. CONCLUSION: A donor-recipient age-difference > 11 years is independently associated with higher long-term mortality after adolescent heart transplantation. This finding may help inform acceptable donor selection practice for adolescent heart transplant candidates.

Repeat pediatric heart transplantation: A united network for organ sharing database analysis.

BACKGROUND: A history of congenital heart disease and previous transplantation are each independently associated with worse survival following pediatric heart transplantation. This study aimed to evaluate the characteristics and outcomes of children undergoing repeat heart transplantation in the United States based on the underlying diagnosis. METHODS: The United Network for Organ Sharing database was used to identify 8111 patients aged <18 years undergoing isolated heart transplantation from 2000 to 2021, including 435 (5.4%) repeat transplants. Restricted cubic spline analysis assessed the non-linear relationship between inter-transplant interval and the primary outcome of all-cause mortality or re-transplantation. Multivariable Cox regression assessed the impact of re-transplantation on the primary outcome. Median follow-up was 5.0 (interquartile range 1.9-9.9) years. RESULTS: Repeat transplant patients were older (median age 12 vs. 4 years; p < .001), and less likely to be in UNOS status 1A (66.0%, n = 287 vs. 81.0% n = 6217; p < .001) than primary transplant patients. Freedom from the primary outcome was 51.4% (95% confidence interval [CI] 45.5-57.2) among repeat transplants and 70.5% (95% CI 69.2-71.8) among primary transplants at 10 years (p < .001). Among repeat transplant patients, the relative hazard of the primary outcome became non-significant when the inter-transplant interval >3.6 years. Congenital heart disease was an independent predictor of mortality among primary (HR 1.8, 95% CI 1.6-1.9) but not repeat transplant (HR 1.1, 95% CI .8-1.6) patients. CONCLUSIONS: Long-term outcomes remain poor for patients undergoing repeat heart transplantation, particularly those with an inter-transplant interval <3.6 years. Underlying diagnosis does not impact outcomes after repeat transplantation, after accounting for other risk factors.

Socioeconomic disparities in midterm outcomes after repair for degenerative mitral regurgitation.

OBJECTIVE: The influence of socioeconomic disparities on survival after mitral repair is poorly defined. We examined the association between socioeconomic disadvantage and midterm outcomes of repair in Medicare beneficiaries with degenerative mitral regurgitation. METHODS: US Centers for Medicare and Medicaid Services data were used to identify 10,322 patients undergoing isolated first-time repair for degenerative mitral regurgitation between 2012 and 2019. Zip code-level socioeconomic disadvantage was dichotomized with the Distressed Communities Index, which incorporates education level, poverty, unemployment, housing security, median income, and business growth; those with Distressed Communities Index score ≥80 were classified as distressed. The primary outcome was survival, censored at 3 years. Secondary outcomes included cumulative incidences of heart failure readmission, mitral reintervention, and stroke. RESULTS: Of the 10,322 patients undergoing degenerative mitral repair, 9.7% (n = 1003) came from distressed communities. Patients from distressed communities underwent surgery at lower volume centers (11 vs 16 cases/year) and traveled further for surgical care (40 vs 17 miles) (both P values < .001). At 3 years, unadjusted survival (85.4%; 95% CI, 82.9%-87.5% vs 89.7%; 95% CI, 89.0%-90.4%) and cumulative incidence of heart failure readmission (11.5%; 95% CI, 9.6%-13.7% vs 7.4%; 95% CI, 6.9%-8.0%) were worse in patients from distressed communities (all P values < .001), whereas mitral reintervention rates were similar (2.7%; 95% CI, 1.8%-4.0% vs 2.8%; 95% CI, 2.5%-3.2%; P = .75). After adjustment, community distress was independently associated with 3-year mortality (hazard ratio, 1.21; 95% CI, 1.01-1.46) and heart failure readmissions (hazard ratio, 1.28; 95% CI, 1.04-1.58). CONCLUSIONS: Community-level socioeconomic distress is associated with worse outcomes in degenerative mitral repair among Medicare beneficiaries.

Left atrial appendage closure during mitral repair in patients without atrial fibrillation.

OBJECTIVE: Routine left atrial appendage closure during mitral repair in patients without atrial fibrillation (AF) is controversial. We aimed to compare the incidence of stroke after mitral repair in patients without recent AF according to left atrial appendage closure. METHODS: An institutional registry identified 764 consecutive patients without recent AF, endocarditis, prior appendage closure, or stroke undergoing isolated robotic mitral repair between 2005 and 2020. Left atrial appendages were closed via left atriotomy using a double-layer continuous suture in 5.3% (15 out of 284) patients before 2014, versus 86.7% (416 out of 480) after 2014. The cumulative incidence of stroke (including transient ischemic attack) was determined using statewide hospital data. Median follow-up was 4.5 years (range, 0-16.6 years). RESULTS: Patients undergoing left atrial appendage closure were older (63 vs 57.5 years, P < .001), with higher prevalence of remote AF requiring cryomaze (9%, n = 40 vs 1%, n = 3, P < .001). After appendage closure there were fewer reoperations for bleeding (0.7% [n = 3] vs 3% [n = 10]; P = .02), and more AF (31.8% [n = 137] vs 25.2% [n = 84]; P = .047). Two-year freedom from >2+ mitral regurgitation was 97%. Six strokes and 1 transient ischemic attack occurred after appendage closure compared with 14 and 5 in patients without (P = .002), associated with a significant difference in 8-year cumulative incidence of stroke/transient ischemic attack (hazard ratio, 0.3; 95% CI, 0.14-0.85; P = .02). This difference persisted in the sensitivity analysis, excluding patients undergoing concomitant cryomaze procedures. CONCLUSIONS: Routine left atrial appendage closure during mitral repair in patients without recent AF appears safe and was associated with a lower risk of subsequent stroke/transient ischemic attack.

Bridging with surgically placed microaxial left ventricular assist devices: a high-volume centre experience.

OBJECTIVES: The Impella 5.0 and 5.5 have largely superseded non-ambulatory temporary mechanical support devices; yet, clinical outcomes are predominantly limited to small series: this study presents the experience of a high-volume centre. METHODS: An institutional clinical registry was used to identify all patients with cardiogenic shock who underwent Impella 5.0 or 5.5 implantation from January 2014 to March 2022. The primary outcome was survival to device explantation. RESULTS: The study cohort comprised 221 patients, including 146 (66.1%) Impella 5.0 and 75 (33.9%) Impella 5.5 patients. The primary aetiology was non-ischaemic cardiomyopathy (50.7%, n = 112), ischaemic cardiomyopathy (23.1%, n = 51) and acute myocardial infarction (26.2%, n = 58). Patients were prospectively classified according to strategy as bridge to transplant (47.5%, n = 105), bridge to durable device (13.6%, n = 30) or bridge to recovery (38.9%, n = 86). Patients were predominantly Interagency Registry for Mechanically Assisted Circulatory Support profile 1 or 2 (95.0%, n = 210). The median bridging duration was 14 (range 0-137) days. Device exchange, Ischaemic stroke and ipsilateral arm ischaemia occurred in 8.1% (n = 18), 2.7% (n = 6) and 1.8% (n = 4) of patients, respectively. Compared to the 75 most recent Impella 5.0 patients, Impella 5.5 patients (n = 75) had lower rates of device exchange (4.0%, n = 3 vs 13.3%, n = 10, P = 0.04). Overall, 70.1% (n = 155) of patients survived to Impella explantation. CONCLUSIONS: The Impella 5.0 and 5.5 provide safe and effective temporary mechanical support in appropriately selected patients with cardiogenic shock. The newer device generation may have a lower requirement for device exchange as compared to its predecessor.

Heart transplantation for COVID-19 myopathy in the United States.

Evidence on characteristics and outcomes of patients undergoing heart transplantation for coronavirus disease 2019 (COVID-19) associated cardiomyopathy is limited to case reports. Of all 6,332 patients aged ≥18 years undergoing heart transplantation from July 2020 through May 2022 in the United Network for Organ Sharing database, 12 (0.2%) patients had COVID-19 myocarditis and 98 (1.6%) patients with the same level of care had non-COVID-19 myocarditis. Their median age was 49 (range 19-74) years. All patients were hospitalized in the intensive care unit and 92.7% (n = 102) were on life support prior to transplantation. No patients with COVID-19 myocarditis required ventilation while waitlisted. Survival free from graft failure was 100% among COVID-19 patients and 88.5% among non-COVID-19 patients at a median of 257 (range 0-427) days post-transplant. These findings indicate that transplantation is rarely performed for COVID-19 related cardiomyopathy in the United States, yet early outcomes appear favorable in select patients.

Isolated Tricuspid Operations: The Society of Thoracic Surgeons Adult Cardiac Surgery Database Analysis.

BACKGROUND: Population-level data are limited regarding contemporary practice and outcomes of isolated tricuspid operations. We evaluated this using The Society of Thoracic Surgeons Adult Cardiac Surgery Database. METHODS: We identified 14,704 isolated tricuspid operations from The Society of Thoracic Surgeons Adult Cardiac Surgery Database from July 1, 2011 to June 30, 2020. After excluding patients with endocarditis, tricuspid stenosis, emergent/emergent salvage status, previous heart transplants, and missing tricuspid operation type, 6507 patients remained. Endpoints were operative mortality and composite major comorbidities (permanent stroke, renal failure, prolonged ventilation > 24 hours, deep sternal wound infection, cardiac reoperations, and new permanent pacemaker implantation). RESULTS: Isolated tricuspid operations increased from 2012 (983 cases) to 2019 (2155 cases, P < .001). Median annual center volume was 2 cases (range, 1-81). In the final cohort (n = 6507; median age, 65 years; 38.5% men), 40% had New York Heart Association class III/IV heart failure and 24% had nonelective operations. The operative mortality was 7.3% (1.7% in patients without these risk factors), and new permanent pacemaker implant rate was 10.8%. In the multivariable analysis, factors associated with operative mortality included New York Heart Association class III/IV heart failure (odds ratio [OR], 1.57), nonelective operations (OR, 1.91), tricuspid replacement (OR, 1.56), annual center volume ≤ 5 cases (OR, 1.37), and higher model for end-stage liver disease scores (all P < .05). Beating heart operation was associated with a lower adjusted risk of pacemaker implant (OR, 0.69), renal failure (OR, 0.75), and blood transfusions (OR, 0.8) compared with full cardioplegic arrest (all P < .05). CONCLUSIONS: Isolated tricuspid repair was associated with lower adjusted mortality and morbidities than replacement. Beating heart operation was associated with lower adjusted major morbidities. The preoperative model for end-stage liver disease scores may identify high-risk patients, and early referral to higher volume centers may help improve outcomes.

Heart transplantation using donation after circulatory death in the United States.

OBJECTIVES: Heart donation after circulatory death was recently reintroduced in the United States with hopes of increasing donor heart availability. We examined its national use and outcomes. METHODS: The United Network for Organ Sharing database was used to identify validated adult patients undergoing heart transplantation using donation after circulatory death donors (n = 266) and donation after brain death donors (n = 5998) between December 1, 2019, and December 31, 2021, after excluding heart-lung transplants. Propensity score matching was used to create more balanced groups for comparison. RESULTS: The monthly percentage of donation after circulatory death heart transplant increased from 2.5% in December 2019 to 6.8% in December 2021 (P < .001). Twenty-two centers performed donation after circulatory death heart transplants, ranging from 1 to 75 transplants per center. Four centers performed 70% of the national volume. Recipients of donation after circulatory death hearts were more likely to be clinically stable (80.4% vs 41.1% in status 3-6, P < .001), to have type O blood (58.3% vs 39.9%, P < .001), and to wait longer after listing (55, interquartile range, 15-180 days vs 32, interquartile range, 9-160 days, P = .003). Six-month survival was 92.1% (95% confidence interval, 91.3-92.8) after donation after brain death heart transplants and 92.6% (95% confidence interval, 88.1-95.4) after donation after circulatory death heart transplants (hazard ratio, 0.94, 95% confidence interval, 0.57-1.54, P = .79). Outcomes in propensity-matched patients were similar except for higher rates of treated acute rejection in donation after circulatory death transplants before discharge (14.4% vs 8.8%, P = .01). In donation after circulatory death heart recipients, outcomes did not differ based on the procurement technique (normothermic regional perfusion vs direct procurement and perfusion). CONCLUSIONS: Heart transplantation with donation after circulatory death donors has short-term survival comparable to donation after brain death transplants. Broader implementation could substantially increase donor organ availability.

Ross Procedure in Children: The Society of Thoracic Surgeons Congenital Heart Surgery Database Analysis.

BACKGROUND: Single-center studies have demonstrated excellent results for the Ross procedure in children. We aimed to evaluate national variation in clinical outcomes using The Society of Thoracic Surgeons Congenital Heart Surgery Database. METHODS: The database was used to identify 2805 children undergoing the Ross procedure from 2000 through 2018, comprising 163 neonates (<30 days, 5.8%), 448 infants (30-365 days, 16.0%), 1444 children (1-12 years, 51.5%), and 750 teenagers (13-17 years, 26.7%). Centers were divided into terciles by procedural volume. Multivariable logistic regression was used to identify predictors of a composite outcome of operative mortality, neurologic deficit, or renal failure requiring dialysis. RESULTS: Neonates and infants were more likely to present with aortic stenosis than children and teenagers (61.7% [n = 377] vs 34.6% [n = 760]; P < .01) and have risk factors including preoperative shock (9.2% [n = 56] vs 0.4% [n = 8]; P < .01). Operative mortality was 24.1% (n = 39) in neonates, 11.2% (n = 50) in infants, 1.5% (n = 21) in children , and 0.8% (n = 6) in teenagers (P < .01). Independent predictors of the composite outcome in children aged <1 year included neonatal age (odds ratio [OR], 3.0; 95% CI, 1.9-4.8), low-volume center (OR, 2.1; 95% CI, 1.1-3.9), and procedure year (OR, 0.7; 95% CI, 0.5-0.9 per 5 years). In children aged ≥1 year, no association was found between center volume, procedure year, and outcome. CONCLUSIONS: The Ross procedure is being performed with low mortality in children aged ≥1 year throughout North America. High-volume centers have improved outcomes in children aged <1 year, who have different anatomic characteristics and risk profiles.

Sex Disparities in Failure to Rescue After Cardiac Surgery in California and New York.

BACKGROUND: Women have a higher risk of mortality than men after cardiac surgery independent of other risk factors. The reason for this may not be limited to patient-specific variables. Failure to rescue (FTR) patients from death after a postoperative complication is a nationally endorsed quality care metric. We aimed to identify whether sex disparities exist in the quality of care after cardiac surgery using FTR rates. METHODS: A retrospective analysis of 30 973 men (70.4%) and 13 033 women (29.6%) aged over 18 years undergoing coronary artery bypass graft or valve surgery in New York (2016-2019) and California (2016-2018) who experienced at least one serious postoperative complication. The primary outcome was the FTR. Multivariable logistic regression was used to identify predictors of death after complication. Propensity matching was used to adjust for baseline differences between sexes and yielded 12 657 pairs. RESULTS: Female patients that experienced complications were older (mean age 67.8 versus 66.7, P<0.001), more frail (median frailty score 0.1 versus 0.07, P<0.001), and had more comorbidities (median Charlson score 2.5 versus 2.3, P<0.001) than male patients. The overall FTR rate was 5.7% (2524), men were less likely to die after a complication than women (4.8% versus 8%, P<0.001). Independent predictors of FTR included female sex (relative risk [RR]: 1.46 [CI, 1.30-1.62]), area-level poverty rate >20% (RR, 1.21 [CI, 1.01-1.59]), higher frailty (RR, 2.83 [CI, 1.35-5.93]), undergoing concomitant coronary artery bypass graft and valve surgeries (RR, 1.69 [CI, 1.49-1.9]), and higher number of postoperative complications (RR, 16.28 [CI, 14-18.89]). In the propensity-matched cohorts, the FTR rate remained significantly lower among men than women (6.0% versus 8.0%, P<0.001). CONCLUSIONS: Women are less likely to be rescued from death following postoperative complications, independent of socioeconomic and clinical characteristics. Further research is warranted to investigate the clinical practices contributing to this disparity in quality of care following cardiac surgery.

Robotic degenerative mitral repair: Factors associated with intraoperative revision and impact of mild residual regurgitation.

OBJECTIVES: National registry data show wide variability in degenerative mitral repair rates and infrequent use of intraoperative repair revision to eliminate residual mitral regurgitation (MR). The consequence of uncorrected mild residual MR is also not clear. We identified factors associated with intraoperative revision of degenerative mitral repair and evaluated long-term effects of intraoperative mild residual MR. METHODS: A prospective institutional registry of 858 patients with degenerative MR undergoing robotic mitral surgery was linked to statewide databases. Univariate logistic regression identified factors associated with intraoperative repair revision. Survival was estimated using the Kaplan-Meier method and adjusted with Cox regression. Late freedom from more-than-moderate MR or reintervention was estimated with death as a competing risk. RESULTS: Repair rate was 99.3%. Repair was revised intraoperatively in 19 patients and was associated with anterior or bileaflet prolapse, adjunctive repair techniques, and annuloplasty band size (all P < .05). Intraoperative repair revision did not result in increased postoperative complications. Intraoperative mild residual MR (n = 111) was independently associated with inferior 8-year survival (hazard ratio, 2.97; 95% CI, 1.33-6.23), worse freedom from more than moderate MR (hazard ratio, 3.35; 95% CI, 1.60-7.00), and worse freedom from mitral reintervention (hazard ratio, 6.40; 95% CI, 2.19-18.72) (all P < .01). CONCLUSIONS: A near 100% repair rate with acceptable durability may be achieved safely with intraoperative revision of postrepair residual MR. Mild residual MR was independently associated with reduced survival, worse freedom from more-than-moderate MR, and worse freedom from mitral reintervention at 8-year follow-up.

Radio-Frequency Manipulation of State Populations in an Entangled Fluorine-Muon-Fluorine System.

Entangled spin states are created by implanting muons into single-crystal LiY_{0.95}Ho_{0.05}F_{4} to form a cluster of correlated, dipole-coupled local magnetic moments. The resulting states have well-defined energy levels allowing experimental manipulation of the state populations by electromagnetic excitation. Experimental control of the evolution of the muon spin polarization is demonstrated through application of continuous, radio-frequency electromagnetic excitation fields. A semiclassical model of quantum, dipole-coupled spins interacting with a classical, oscillating magnetic field accounts for the muon spin evolution. On application of the excitation field, this model shows how changes in the state populations lead to the experimentally observed effects, thus enabling a spectroscopic probe of entangled spin states with muons.

Robotic repair for Barlow mitral regurgitation: Repairability, safety, and durability.

OBJECTIVE: In Barlow disease, increased repair complexity drives decreased repair rates. We evaluated outcomes of a simplified approach to robotic mitral repair in Barlow disease. METHODS: A prospective institutional registry with vital-statistics, statewide admissions and echocardiographic follow-up was used to identify 924 consecutive patients undergoing robotic surgery for degenerative mitral regurgitation (MR) between 2005 and 2020, including 12% (n = 111) with Barlow disease. Freedom from >moderate (>2+) MR was analyzed with death as a competing risk and predictors of failure were analyzed using multivariable Cox regression. Median follow-up was 5.5 years (range, 0-15 years). RESULTS: Patients with Barlow disease were younger (median, age 59 years; interquartile range [IQR], 51-67 vs 62; IQR, 54-70 years, P = .05) than patients without Barlow disease. Replacements were performed in 0.9% (n = 1) of patients with Barlow disease and 0.8% (n = 6) of patients without Barlow disease (P = 1). Repairs comprised simple leaflet resection and annuloplasty band in 73.9% (n = 546) of non-Barlow valves versus 12.7% (n = 14) of patients with Barlow disease who required neochordae (53.6%, n = 59), chordal transfer (20%, n = 22), and commissural sutures (37.3%, n = 41), with longer cardiopulmonary bypass time (median 133; IQR, 117-149 minutes vs 119; IQR, 106-142 minutes, P < .01). Survival free from greater than moderate MR at 5 years was 92.0% (95% confidence interval [CI], 80.2%-98.1%) in patients with Barlow disease versus 96.0% (95% CI, 93.3%-98.0%) in patients without Barlow disease (P = .40). Predictors of late failure included Barlow disease (hazard ratio, 3.9; 95% CI, 1.7-9.0) and non-Barlow isolated anterior leaflet prolapse (hazard ratio, 5.6; 95% CI, 2.3-13.4). CONCLUSIONS: Barlow disease may be reliably and safely repaired with acceptable long-term durability by experienced robotic mitral surgery programs.