Association between preoperative right heart catheterization parameters and outcomes in patients undergoing isolated coronary artery bypass grafting.

Right ventricular catheterization may capture information that can help define prognosis before coronary artery bypass grafting (CABG). In this study, we evaluate the association between preoperative right heart catheterization parameters and outcomes of patients undergoing isolated CABG. All patients undergoing isolated CABG at our institution from 2013 to 2021 who also underwent preoperative right heart catheterization <14 days prior to isolated CABG were retrospectively queried. A total of 2343 patients underwent isolated CABG of whom 78 patients [20 (25.6%) female] were included in the final analysis. On multivariable regression, central venous pressure was significantly associated with operative mortality (odds ratio 1.14, 95% confidence interval 1.02-1.27, P = 0.024). Preoperative cardiac index was significantly inversely associated with intensive care unit length of stay (odds ratio 0.72, 95% confidence interval 0.62-0.84, P < 0.001) and duration of inotropic support (odds ratio 0.76, 95% confidence interval 0.63-0.92, P < 0.01). Assessment of preoperative cardiac function by right heart catheterization should be considered in high-risk patient populations, particularly those who have significant left ventricular dysfunction on preoperative echocardiography that would make them candidate for percutaneous coronary intervention, left ventricular assist device or heart transplantation. Further, right heart catheterization can help to guide preoperative optimization and intra-/postoperative decision-making.

Bleeding is associated with severely impaired outcomes in surgery for acute type a aortic dissection.

Background. Surgery for acute type A aortic dissection confers a risk for significant bleeding. We analyzed the impact of massive bleeding on complications after surgery for acute type A aortic dissection. Methods. Patients undergoing surgery for acute type A aortic dissection from the retrospective multicenter Nordic Consortium for Acute Type A Aortic Dissection (NORCAAD) database 2005-2014 were eligible. Massive bleeding was defined according to the Universal Definition of Perioperative Bleeding. The primary outcome measure was early mortality and secondary outcome measures were perioperative stroke, mechanical ventilation more than 48 h, new-onset dialysis, and intensive care unit stay. Propensity score matching was performed to adjust for differences in covariates. Results. Nine hundred ninety-seven patients were included, of whom 403 (40.4%) had massive bleeding. In the propensity score-matched cohort (344 pairs), patients with massive bleeding had higher 30-day mortality (17.2 versus 7.6%, p < .001), mechanical ventilation more than 48 h (52.8 versus 22.6%, p < .001), perioperative stroke (24.3 versus 14.8%, p = .002), new-onset dialysis (22.5 versus 4.9%, p < .001), and longer intensive care unit stay (6 versus 3 days, p < .001), compared with patients without massive bleeding. Risk factors for massive bleeding were previous cardiac surgery, preoperative clopidogrel or ticagrelor therapy, DeBakey type I dissection, and localized or generalized malperfusion. Conclusions. Massive bleeding in surgery for acute type A aortic dissection is associated with a markedly increased risk for severe complications as well as early death. Further improvement of surgical technique and pharmacological optimization of coagulation is paramount to possibly improve outcomes in acute type A aortic dissection repair.

Developing Proficiency in Robotic Cardiac Surgery.

The purpose of this manuscript is to provide recommendations for cardiac surgeons interested in adopting a robotic platform into their programs. The recommendations are based on the experience of the authors and cover a diverse array of cardiac surgical procedures that are currently being performed with robotic assistance. The focus, as with any innovative surgical approach, is to ensure patient safety, maximize quality and efficacy, and to set realistic expectations about what is required to achieve proficiency in robotic cardiac surgery.

Mechanical versus biological mitral valve replacement: Insights from propensity score matching on survival and reoperation rates.

OBJECTIVES: Patients with symptomatic mitral valve disease unsuitable for repair can be sufficiently treated with surgical mitral valve replacement. The decision between biological and mechanical mitral valve replacement can be difficult, especially due to the question of the lesser of 2 evils: anticoagulation versus reoperation. METHODS: This single-center, retrospective study included all patients undergoing mitral valve replacement between 2001 and 2020. Thirty-day mortality and periprocedural complications were analyzed. Propensity score matching adjusted for age, gender, weight, height, endocarditis, diabetes, hypertension, peripheral arterial occlusive disease, atrial fibrillation, chronic kidney disease, cancer, and history of neurological disorders was performed. After propensity score matching, survival and cumulative incidence of reoperation at time of follow-up were analyzed. RESULTS: The study included 2027 patients in 2 main groups: 1658 patients with biological mitral valve replacement and 369 patients with mechanical mitral valve replacement; 51.2% were male. Age at surgery was 65.9 ± 12.9 years. Median follow-up time was 6.83 years (interquartile range, 1.11-10.61 years). Concomitant procedures were performed in 1467 cases (72.4%). Propensity score matching yielded comparable groups of 339 pairs. Both groups showed comparable survival (P = .203). Survival after mechanical mitral valve replacement and biological mitral valve replacement was comparable for all analyzed time points over the course of 20 years. Patients with mechanical mitral valve replacement showed a significantly lower cumulative incidence for reoperation (20 years: 15% vs 59%, P < .001). CONCLUSIONS: Follow-up of 20 years at a high-volume center demonstrates comparable survival after mechanical or biological mitral valve replacement, whereas reoperation rates are significantly lower after mechanical mitral valve replacement.

Gender and Sex Differences in the Management, Intervention, and Outcomes of Patients With Severe Primary Mitral Regurgitation.

BACKGROUND: Gender- and sex-based disparities in mitral valve disease exist; however the factors associated with these differences are unknown. Identifying these differences is essential in devising mitigating strategies. We evaluated gender and sex differences among patients with severe primary mitral regurgitation (MR) across treatment phases. METHODS AND RESULTS: We conducted a retrospective cohort study of patients with new diagnoses of severe primary MR between 2016 and 2020. We compared multidisciplinary evaluation incidence and 2-year survival between men and women. We analyzed a subgroup meeting class 1 indications for intervention, which includes severe symptomatic MR or severe asymptomatic MR with ejection fraction <60% or left ventricular end-systolic diameter >40 mm. Logistic regression models identified predictors associated with the likelihood of multidisciplinary evaluation. Among 330 patients meeting class 1 indications, women were older (79 versus 76 years, P=0.01) and had higher Society of Thoracic Surgeons risk scores for mitral valve repair than men (2.5% versus 1.4%, P=0.003). Women were less likely to undergo multidisciplinary evaluation (57% versus 84%, P<0.001) and intervention (47% versus 69%, P<0.001) than men. Median days to intervention for women and men were 77 and 43, respectively. Women had a higher 2-year mortality rate than men (31% versus 21%, P=0.035). On a multivariable model, female sex and older age were associated with lower odds of undergoing multidisciplinary evaluation (odds ratio, 0.26; P<0.001; odds ratio, 0.95; P<0.001, respectively). CONCLUSIONS: Women with severe primary MR with class 1 indication for intervention were less likely to undergo multidisciplinary evaluation and intervention and had a longer interval to intervention than men. Survival was comparable after accounting for age and comorbidity differences.

Functional Mitral Valve Regurgitation: Mitral Valve Repair or Replacement? Our "Road Map" for the Appropriate Strategy.

Objectives: The optimal surgical approach for the treatment of functional mitral regurgitation (FMR) remains controversial. Current guidelines suggest that the surgical approach has to be tailored to the individual patient. The aim of the present study was to clarify further aspects of this tailored treatment. Methods: From 01/2006 to 12/2015, 390 patients underwent mitral valve (MV) surgery for FMR (ischemic n = 241, non-ischemic n = 149) at our institution. A regression analysis was used to determine the effect of MV repair or replacement on survival. The patients were analyzed according to the etiology of the MR (ischemic or non-ischemic), different age groups (<65 years, 65-75 years, and >75 years), LV function, and LV dimensions, as well as the underlying heart rhythm. Results: The overall survival rates for the repair group at 1, 5, and 8 years were 86.1 ± 1.9%, 70.6 ± 2.6%, and 55.1 ± 3.1%, respectively. For the same intervals, the survival rates in patients who underwent MV replacement were 75.9 ± 4.5%, 58.6 ± 5.4%, and 40.9 ± 6.4%, respectively (p = 0.003). Patients younger than 65 years, with an ischemic etiology of FMR, poor ejection fraction (<30%), severe dilatation of left ventricle (LVEDD > 60mm), and presence of atrial fibrillation had significantly higher mortality rates after MV replacement (HR, 3.0; CI, 1.3-6.9; p = 0.007). Patients between 65 and 75 years of age had a higher risk of death when undergoing mitral valve replacement (HR, 1.7; CI, 1.0-2.8; p = 0.04). In patients older than 75 years, the surgical approach (MV repair or replacement) had no effect on postoperative survival (HR, 0.8; CI, 0.4-1.3; p = 0.003). Conclusions: Our data demonstrate that, in patients younger than 65 years, the treatment of choice for FMR should be MV repair. This advantage was even more evident in patients with an ischemic origin of MR, a poor ejection fraction, a severe LV dilatation, and atrial fibrillation.

Transcatheter heart valve explant with infective endocarditis-associated prosthesis failure and outcomes: the EXPLANT-TAVR international registry.

BACKGROUND AND AIMS: Surgical explantation of transcatheter heart valves (THVs) is rapidly increasing, but there are limited data on patients with THV-associated infective endocarditis (IE). This study aims to assess the outcomes of patients undergoing THV explant for IE. METHODS: All patients who underwent THV explant between 2011 and 2022 from 44 sites in the EXPLANT-TAVR registry were identified. Patients with IE as the reason for THV explant were compared to those with other mechanisms of bioprosthetic valve dysfunction (BVD). RESULTS: A total of 372 patients from the EXPLANT-TAVR registry were included. Among them, 184 (49.5%) patients underwent THV explant due to IE and 188 (50.5%) patients due to BVD. At the index transcatheter aortic valve replacement, patients undergoing THV explant for IE were older (74.3 ± 8.6 vs. 71 ± 10.6 years) and had a lower Society of Thoracic Surgeons risk score [2.6% (1.8-5.0) vs. 3.3% (2.1-5.6), P = .029] compared to patients with BVD. Compared to BVD, IE patients had longer intensive care unit and hospital stays (P < .05) and higher stroke rates at 30 days (8.6% vs. 2.9%, P = .032) and 1 year (16.2% vs. 5.2%, P = .010). Adjusted in-hospital, 30-day, and 1-year mortality was 12.1%, 16.1%, and 33.8%, respectively, for the entire cohort, with no significant differences between groups. Although mortality was numerically higher in IE patients 3 years postsurgery (29.6% for BVD vs. 43.9% for IE), Kaplan-Meier analysis showed no significant differences between groups (P = .16). CONCLUSIONS: In the EXPLANT-TAVR registry, patients undergoing THV explant for IE had higher 30-day and 1-year stroke rates and longer intensive care unit and hospital stays. Moreover, patients undergoing THV explant for IE had a higher 3-year mortality rate, which did not reach statistical significance given the relatively small sample size of this unique cohort and the reduced number of events.

The high-risk features among patients undergoing mitral valve operation for ischemic mitral regurgitation: The 3-strike score.

Objective: Ischemic mitral regurgitation is prevalent and associated with high surgical risk. With the less-invasive option of transcatheter edge-to-edge repair, the optimal patient selection for mitral valve operation for ischemic mitral regurgitation remains unclear. We sought to identify high-risk features in this group to guide patient selection. Methods: Using the Cardiothoracic Surgery Trial Network's severe ischemic mitral regurgitation trial data, we identified patient and echocardiographic characteristics associated with an increased risk of 2-year mortality using the support vector classifier and Cox proportional hazards model. We identified 6 high-risk features associated with 2-year survival. Patients were categorized into 3 groups, each having 1 or less, 2, or 3 or more of the 6 identified high-risk features. Results: Among the 251 patients, the median age was 69 (Q1 62, Q3 75) years, and 96 (38%) were female. Two-year mortality was 21% (n = 53). We identified 6 high-risk preoperative features: age 75 years or more (n = 69, 28%), prior sternotomy (n = 49, 20%), renal insufficiency (n = 69, 28%), gastrointestinal bleeding (n = 15, 6%), left ventricular ejection fraction less than 40% (n = 131, 52%), and ventricular end-systolic volume index less than 50 mL/m2 (n = 93, 37%). In patients who had 1 or less, 2, and 3 or more high-risk features, 90-day mortality was 4.2% (n = 5), 9.9% (n = 4), and 20.0% (n = 10), respectively (P = .006), and 2-year mortality was 10% (n = 12), 22% (n = 18), and 46% (n = 23) (P < .001), respectively. Conclusions: We developed the 3-strike score by identifying high-risk preoperative features for mitral valve surgery for ischemic mitral regurgitation. Patients having 3 or more of such high-risk features should undergo careful evaluation for surgical candidacy given the high early and late mortality after mitral valve operations.

Living in disadvantaged neighborhoods linked to less intervention for severe aortic stenosis.

To investigate the association between area deprivation index (ADI) and aortic valve replacement (AVR) in patients with severe aortic stenosis (AS). Patients aged 40-95 years with severe AS confirmed by echocardiography were included. The 9-digit zip code of patient residence address was used to identify the ADI ranking, based on which patients were divided into 5 groups (with Group E being most deprived). The rates of AV intervention were compared among 5 groups using competing risks analysis, with death as a competing event. We included 1751 patients with severe AS from 2013 to 2018 followed for a median 2.8 (interquartile range, 1.5-4.8) years. The more distressed ADI groups tended to be younger (P = 0.002), female (P < 0.001), and of African American race (P < 0.001), have higher presentation of sepsis (P = 0.031), arrhythmia (P = 0.022), less likely to have previous diagnosis of AS (P < 0.001); and were less likely to undergo AVR (52.5% vs 46.9% vs 46.1% vs 48.9% vs 39.7%, P = 0.023). Using competing risk analysis, the highest ADI group (E) were the least and the lowest ADI group (A) the most likely to undergo AVR (Gray's test, P = 0.025). The association between ADI ranking and AVR rates was influenced by sex and race. Within group analysis, there was significant association between race and AVR (Gray's test, P < 0.001), and between sex and AVR (Gray's test, P < 0.001). Patients with severe AS living in more deprived neighborhoods were less likely to undergo aortic valve interventions, which was influenced by female gender, and African American race.

Implementing Formal Mitral Heart Team Improves Multidisciplinary Evaluation Rate and Survival of Patients With Severe Primary Mitral Regurgitation.

BACKGROUND: Multidisciplinary heart team (HT) evaluation is recommended for patients with severe primary mitral regurgitation to optimize treatment decisions. However, its impact on patient outcomes remains unknown. We evaluated the impact of implementing mitral HT on patient survival. METHODS AND RESULTS: We conducted a retrospective cohort study of patients with new diagnoses of severe primary mitral regurgitation in a large healthcare network echocardiogram database between 2016 and 2020. We compared the incidence of multidisciplinary evaluation by structural cardiology and cardiac surgery services and 2-year survival before and after mitral HT implementation. The 1:1 propensity-score matching between pre- and post-mitral HT used Society of Thoracic Surgeons Predicted Risk of Mortality for mitral repair, age, sex, race, heart failure symptoms, inpatient setting, history of MI, and dementia as covariates. Logistic regression identified variables associated with the likelihood of undergoing multidisciplinary evaluation. Among 70 510 echocardiograms performed, 391 patients had severe primary mitral regurgitation (median age, 77 years; 46% women). Multidisciplinary evaluation increased from 29% to 89% (P<0.001), and intervention increased from 24% to 75% following mitral HT implementation (P<0.001). Among 180 propensity-score matched patients, mortality was lower post-mitral HT at 2 years (19% versus 32%, P=0.04). The multivariable model showed that mitral HT implementation and heart failure symptoms were associated with higher odds of undergoing multidisciplinary evaluation (OR [odds ratio], 18.7 and 2.72, respectively), whereas female sex and older age were associated with lower odds (OR, 0.39 and 0.93, respectively). CONCLUSIONS: Implementation of mitral HT was associated with drastic improvement in multidisciplinary evaluation for patients with severe primary mitral regurgitation. This coincided with higher proportions of patients undergoing mechanical correction of MR and improved overall patient survival.

Extremely Long-Term Follow-Up of Dr William Glenn's Original Patient Cohort With Superior Cavopulmonary Anastomosis (1958-1990).

BACKGROUND: Historically, Dr William Glenn performed the first classic superior cavopulmonary anastomosis in a seven-year-old child at Yale in 1958. By 1990, this operation was performed consecutively in over 90 patients. With over 60 years of follow-up, this is the longest survival record of early Glenn patients from the first 30 years. METHODS: We performed a single center, retrospective evaluation of patients undergoing a Glenn operation. A collected list of surviving patients, previously updated in 1988, included demographics, age at procedure, and underlying diagnosis. Follow-up data were obtained in May 2022 using electronic medical records to determine survival, age of survivors, and age of deceased. RESULTS: Ninety-five patients underwent the Glenn operation from 1958 to 1990: 58.9% (n = 56) were male and 41.1% (n = 39) female. Fifteen patients were lost to follow-up, but 12 were alive in 1988. Sixty patients were deceased (68.1%), with an average age of 33.5 ± 18.3(range, 2-78, excluding seven early deaths) years. The oldest patient who passed away was a 78-year-old male with tetralogy of Fallot. Twenty patients remain alive, with an average age of 47.5 (range, 32-66) years. Four patients who are still alive today (20% survivors) are older than 60 years. CONCLUSIONS: Since Dr Glenn's original operation, the technique, timing, and indications have been modified (ie, bidirectional Glenn) to adapt to the current era. By following this initial group of patients, we can approach completion of the survival rates for adult congenital patients who were some of the first pediatric patients to receive this ground-breaking palliative procedure.

Racial/Ethnic Disparities in Aortic Valve Replacement Among Medicare Beneficiaries in the United States, 2012-2019.

PURPOSE: There are concerns that transcatheter or surgical aortic valve replacement (TAVR/SAVR) procedures are preferentially available to White patients. Our objective was to examine differences in utilization of aortic valve replacement and outcomes by race/ethnicity in the US for patients with aortic stenosis. METHODS: We performed a serial cross-sectional cohort study of 299,976 Medicare beneficiaries hospitalized with principal diagnosis of aortic stenosis between 2012 and 2019 stratified by self-reported race/ethnicity (Black, Hispanic, Asian, Native American, and White). Outcomes included aortic valve replacement rates within 6 months of index hospitalization and associated procedural outcomes, including 30-day readmission, 30-day and 1-year mortality. RESULTS: Within 6 months of an index admission for aortic stenosis, 86.8% (122,457 SAVR; 138,026 TAVR) patients underwent aortic valve replacement. Overall, compared with White people, Black (HR 0.87 [0.85-0.89]), Hispanic (0.92 [0.88-0.96]), and Asian (0.95 [0.91-0.99]) people were less likely to receive aortic valve replacement. Among patients who were admitted emergently/urgently, White patients (41.1%, 95% CI, 40.7-41.4) had a significantly higher aortic valve replacement rate compared with Black (29.6%, 95% CI, 28.3-30.9), Hispanic (36.6%, 95% CI, 34.0-39.3), and Asian patients (35.4%, 95% CI, 32.3-38.9). Aortic valve replacement rates increased annually for all race/ethnicities. There were no significant differences in 30-day or 1-year mortality by race/ethnicity. CONCLUSIONS: Aortic valve replacement rates within 6 months of aortic stenosis admission are lower for Black, Hispanic, and Asian people compared to White people. These race-related differences in aortic stenosis treatment reflect complex issues in diagnosis and management, warranting a comprehensive reassessment of the entire care spectrum for disadvantaged populations.

Assessment of online information on robotic cardiac and thoracic surgery.

Online health resources are important for patients seeking perioperative information on robotic cardiac and thoracic surgery. The value of the resources depends on their readability, accuracy, content, quality, and suitability for patient use. We systematically assess current online health information on robotic cardiac and thoracic surgery. Systematic online searches were performed to identify websites discussing robotic cardiac and thoracic surgery. For each website, readability was measured by nine standardized tests, and accuracy and content were assessed by an independent panel of two robotic cardiothoracic surgeons. Quality and suitability of websites were evaluated using the DISCERN and Suitability Assessment of Materials tools, respectively. A total of 220 websites (120 cardiac, and 100 thoracic) were evaluated. Both robotic cardiac and thoracic surgery websites were very difficult to read with mean readability scores of 13.8 and 14.0 (p = 0.97), respectively, requiring at least 13 years of education to be comprehended. Both robotic cardiac and thoracic surgery websites had similar accuracy, amount of content, quality, and suitability (p > 0.05). On multivariable regression, academic websites [Exp (B)], 2.25; 95% confidence interval [CI], 1.60-3.16; P < 0.001), and websites with higher amount of content [Exp (B)],1.73; 95% CI, 1.24-2.41; P < 0.001) were associated with higher accuracy. There was no association between readability of websites and accuracy [Exp (B)], 1.04; 95% CI, 0.90-1.21; P = 0.57). Online information on robotic cardiac and thoracic surgery websites overestimate patients' understanding and require at least 13 years of education to be comprehended. As website accuracy is not associated with ease of reading, the readability of online resources can be improved without compromising accuracy.

Totally endoscopic, robotic-assisted tricuspid valve repair and biatrial CryoMAZE.

We describe in detail our technique for totally endoscopic, robotic-assisted tricuspid valve repair for iatrogenic tricuspid regurgitation and biatrial cryoMAZE.

Robotic Mitral Valve Repair for Degenerative Mitral Regurgitation.

BACKGROUND: Contemporary national utilization and comparative safety data of robotic mitral valve repair for degenerative mitral regurgitation compared with nonrobotic approaches are lacking. The study aimed to characterize national trends of utilization and outcomes of robotic mitral repair of degenerative mitral regurgitation compared with sternotomy and thoracotomy approaches. METHODS: Patients undergoing intended mitral repair of degenerative mitral regurgitation in The Society of Thoracic Surgeons Adult Cardiac Surgery Database between 2015 and 2021 were examined. Mitral repair was performed in 61,322 patients. Descriptive analyses characterized center-level volumes and outcomes. Propensity score matching separately identified 5540 pairs of robotic vs thoracotomy approaches and 6962 pairs of robotic vs sternotomy approaches. Outcomes were operative mortality, composite mortality and major morbidity, postoperative length of stay, and conversion to mitral replacement. RESULTS: Through the 7-year study period, 116 surgeons across 103 hospitals performed mitral repair robotically. The proportion of robotic cases increased from 10.9% (949 of 8712) in 2015 to 14.6% (1274 of 8730) in 2021. In both robotic-thoracotomy and robotic-sternotomy matched pairs, mortality and morbidity were not significantly different, whereas the robotic approach had lower conversion (1.2% vs 3.1% for robotic-thoracotomy and 1.0% vs 3.7% for robotic-sternotomy), shorter length of stay, and fewer 30-day readmissions. Mortality and morbidity were lower at higher-volume centers, crossing the national mean mortality and morbidity at a cumulative robotic mitral repair case of 40. CONCLUSIONS: Robotic mitral repair is a safe and effective approach and is associated with comparable mortality and morbidity, a lower conversion rate, a shorter length of stay, and fewer 30-day readmissions than thoracotomy or sternotomy approaches.

A Retrospective Evaluation of Endo-Aortic Balloon Occlusion Compared to External Clamping in Minimally Invasive Mitral Valve Surgery.

We compare outcomes of endo-aortic balloon occlusion (EABO) vs external aortic clamping (EAC) in patients undergoing minimally invasive mitral valve surgery (MIMVS) in the Society of Thoracic Surgeons (STS) Adult Cardiac Surgery Database. Adults undergoing mitral valve surgery (July 2017-December 2018) were identified within the STS database (N = 60,607). Total 7,978 patients underwent a minimally invasive approach (including robotically assisted). About 1,163 EABO patients were 1:1 propensity-matched to EAC patients using exact matching on age, sex, and type of mitral procedure, and propensity score average matching for 16 other risk indicators. Early outcomes were compared. Categorical variables were compared using logistic regression; hospital and intensive care unit length of stay were compared using negative binomial regression. In the matched cohort, mean age was 62 years; 35.9% were female, and 86% underwent mitral valve repair. Cardiopulmonary bypass time was shorter for EABO vs EAC group (125.0 ± 53.0 vs 134.0 ± 67.0 minutes, P = 0.0009). There was one aortic dissection in the EAC group and none in the EABO group (P value > 0.31), and no statistically significant differences in cross-clamp time, major intraoperative bleeding, perioperative mortality, stroke, new onset of atrial fibrillation, postoperative acute kidney injury, success of repair. Median hospital LOS was shorter for EABO vs EAC procedures (4 vs 5 days, P < 0.0001). In this large, retrospective, STS database propensity-matched analysis ofpatients undergoing MIMVS, we observed similar safety outcomes for EABO and EAC, including no aortic dissections in the EABO group. The EABO group showed slightly shorter CPB times and hospital LOS.