Racial and Ethnic Variations in Patients Undergoing Mitral and Tricuspid Valve Surgery.

INTRODUCTION: Prior investigations assessing the impact of race/ethnicity on outcomes after mitral valve (MV) surgery have reported conflicting findings. This analysis aimed to examine the association between race/ethnicity and operative presentation and outcomes of patients undergoing MV and tricuspid valve (TV) surgery. METHODS: We retrospectively analyzed 5984 patients (2730 female, median age 63 y) who underwent MV (n = 4,534, 76%), TV (n = 474, 8%) or both MV and TV (n = 976, 16%) surgery in a statewide collaborative from 2012 to 2021. The influence of race/ethnicity on preoperative characteristics, MV and TV repair rates, and postoperative outcomes was assessed for White (n = 4,244, 71%), Black (n = 1,271, 21%), Hispanic (n = 144, 2%), Asian (n = 171, 3%), and mixed/other race (n = 154, 3%) patients. RESULTS: Black patients, compared to White patients, had higher Society of Thoracic Surgeons predicted risk of morbidity/mortality (24.5% versus 13.1%; P < 0.001) and more comorbid conditions. Compared to White patients, Black and Hispanic patients were less likely to undergo an elective procedure (White 71%, Black 55%, Hispanic 58%; P < 0.001). Degenerative MV disease was more prevalent in White patients (White 62%, Black 41%, Hispanic 43%, Asian 51%, mixed/other 45%; P < 0.05), while rheumatic disease was more prevalent in non-White patients (Asian 28%, Hispanic 26%, mixed/other 25%, Black 17%, White 10%;P < 0.05). After multivariable adjustment, repair rates and adverse postoperative outcomes, including mortality, did not differ by racial/ethnic group. CONCLUSIONS: Patient race/ethnicity is associated with a higher burden of comorbidities at operative presentation and MV disease etiology. Strategies to improve early detection of valvular heart disease and timely referral for surgery may improve outcomes.

Statewide data on surgical ablation for atrial fibrillation: The data provide a path forward.

OBJECTIVE: Atrial fibrillation (AF), if left untreated, is associated with increased intermediate and long-term morbidity/mortality. Surgical treatment for AF is lacking standardization in patient selection and lesion set, despite clear support from multi-society guidelines. The aim of this study was to analyze a statewide cardiac surgery registry to establish whether or not there is an association between center volume and type of index procedure with performance of surgical ablation (SA) for AF, the lesion set chosen, and ablation technology used. METHODS: Adult, first-time, nonemergency patients with preoperative AF between 2014 and 2022 excluding standalone SA procedures from a statewide registry of Society of Thoracic Surgeons data were included (N = 4320). AF treatment variability by hospital volume (ordered from smallest to largest) and surgery type were examined with χ2 analyses. Hospital-level Spearman correlations compared hospital volume with proportion of AF patients treated with SA. RESULTS: Overall, 37% of patients with AF were ablated at the time of surgery (63% of mitral procedures, 26% of non-mitrals) and 15% had left atrial appendage management only. There was a significant temporal trend of increasing performance of SA for AF over time (Cochran-Armitage = 27.8; P < .001). Hospital cardiac surgery volume did not correlate with the proportion of AF patients treated with SA (rs = 0.19; P = .603) with a rate of SA below the state average for academic centers. Of cases with SA (n = 1582), only 43% had a biatrial lesion set. Procedures that involved mitral surgery were more likely to include a biatrial lesion set (χ2 = 392.3; P < .001) for both paroxysmal and persistent AF. Similarly, ablation technology use was variable by type of concomitant operation (χ2 = 219.0; P < .001) such that radiofrequency energy was more likely to be used in non-mitral procedures. CONCLUSIONS: These results indicate an increase in adoption of SA for AF over time. No association between greater hospital volume or academic status and performance of SA for AF was established. Similar to national data, the type of index procedure remains the most consistent factor in the decision to perform SA with a disconnect between AF pathophysiology and decision making on the type of SA performed. This analysis demonstrates a gap between evidence-based guidelines and real-world practice, highlighting an opportunity to confer the benefits of concomitant SA to more patients.

Unexpected impact of preoperative anemia in low-risk isolated coronary artery bypass grafting or single-valve surgical patients: Do not overlook these patients in anemia management!

OBJECTIVE: Preoperative anemia is prevalent in cardiac surgery and independently associated with increased risk for short-term and long-term mortality. The purpose of this study was to examine the effect of preoperative hematocrit (Hct) on outcomes in cardiac surgical patients and whether the effect is comparable across levels of Society of Thoracic Surgeons Predicted Risk of Mortality (STS PROM). METHODS: The study consisted of adult, isolated coronary artery bypass grafting (CABG) or single-valve surgical patients in a statewide registry from 2011 to 2022 (N = 29,828). Regressions were used to assess effect of preoperative Hct on STS-defined major morbidity/mortality including the interaction of Hct and STS PROM as continuous variables. RESULTS: Median age was 66 years (58-73 years), STS PROM was 1.02% (0.58%-1.99%), and preoperative Hct was 39.5% (35.8%-42.8%). The sample consisted of 78% isolated CABG (n = 23,261), 10% isolated mitral valve repair/replacement (n = 3119), 12% isolated aortic valve replacement (n = 3448), and 29% were female (n = 8646). Multivariable analyses found that greater Hct was associated with reduced risk of STS-defined morbidity/mortality (odds ratio, 0.96; P < .001). These effects for Hct persisted even after adjustment for intraoperative blood transfusion. The interaction of Hct and STS PROM was significant for morbidity/mortality (odds ratio, 1.01; P < .001). There was a stronger association between Hct levels and morbidity/mortality risk in the patients with the lowest STS risk compared with patients with the greatest STS risk. CONCLUSIONS: Patients with lower risk had a greater association between preoperative Hct and major morbidity and mortality compared with patients with greater risk. Preoperative anemia management is essential across all risk groups for improved outcomes.

Impact of intraoperative blood products, fluid administration, and persistent hypothermia on bleeding leading to reexploration after cardiac surgery.

OBJECTIVE: Risk factors for severe postoperative bleeding after cardiac surgery remain multiple and incompletely elucidated. We evaluated the impact of intraoperative blood product transfusions, intravenous fluid administration, and persistently low core body temperature (CBT) at intensive care unit arrival on risk of perioperative bleeding leading to reexploration. METHODS: We retrospectively queried our tertiary care center's Society of Thoracic Surgeons Institutional Database for all index, on-pump, adult cardiac surgery patients between July 2016 and September 2022. Intraoperative fluid (crystalloid and colloid) and blood product administrations, as well as perioperative CBT data, were harvested from electronic medical records. Linear and nonlinear mixed models, treating surgeon as a random effect to account for inter-surgeon practice differences, were used to assess the association between above factors and reexploration for bleeding. RESULTS: Of 4037 patients, 151 (3.7%) underwent reexploration for bleeding. Reexplored patients experienced remarkably greater postoperative morbidity (23% vs 6%, P < .001) and 30-day mortality (14% vs 2%, P < .001). In linear models, progressively increasing IV crystalloid administration (adjusted odds ratio, 1.11, 95% confidence interval, 1.03-1.19) and decreasing CBT on intensive care unit arrival (adjusted odds ratio, 1.20; 95% confidence interval, 1.05-1.37) were associated with greater risk of bleeding leading to reexploration. Nonlinear analysis revealed increasing risk after ∼6 L of crystalloid administration and a U-shaped relationship between CBT and reexploration risk. Intraoperative blood product transfusion of any kind was not associated with reexploration. CONCLUSIONS: We found evidence of both dilution- and hypothermia-related effects associated with perioperative bleeding leading to reexploration in cardiac surgery. Interventions targeting modification of such risk factors may decrease the rate this complication.

Institutional Variability in Red Blood Cell Transfusion With Coronary Bypass in a Statewide Database.

BACKGROUND: The decision to perform transfusion is common but varies among centers and surgeons. This study looked at variables associated with red blood cell (RBC) transfusion in a statewide database. The study aimed to understand discrepancies in transfusion rates among hospitals and to establish whether the hospital itself was a significant variable in transfusion, independent of variables known to affect transfusion in patients undergoing cardiac surgical procedures. METHODS: The Maryland Cardiac Surgery Quality Initiative is a consortium of centers in the state. Patients undergoing isolated coronary artery bypass grafting from January 2018 to June 2020 from 10 centers in Maryland were included. Multivariable logistic regression was used to determine probability of RBC transfusion with covariates, including age, preoperative hemoglobin value, The Society of Thoracic Surgeons predicted risk of mortality, emergency status, preoperative adenosine diphosphate receptor blocker use, sex, body mass index, and off-pump status. RESULTS: A total of 5343 patients were included and had an overall RBC transfusion rate of 30.3% (range, 11.3%-55.8%). There was significant variability in the incidence of RBC transfusion among hospitals (χ2 = 604.7; P < .001). After covariate adjustment, a significant effect of hospital on transfusion remained (Wald = 547.3; P < .001). Hospital variation in RBC transfusion was not correlated with hospital variation in median age (P = .467), hemoglobin (P 0 855), The Society of Thoracic Surgeons predicted risk of mortality (P = .855), or sex (P = .726). CONCLUSIONS: In a statewide analysis, wide variability in transfusion rates was observed, with hospital-specific management strongly associated with RBC transfusion. This study suggests that RBC transfusion may be affected by the culture and practices of an institution independent of clinical and demographic variables.

Contemporary Patterns of Care in Tetralogy of Fallot: Analysis of The Society of Thoracic Surgeons Data.

BACKGROUND: Against the background of earlier studies, recent patterns in surgical management of tetralogy of Fallot (TOF) were assessed. METHODS: A retrospective review of The Society of Thoracic Surgeons (STS) Congenital Database (2010-2020) was performed on patients aged <18 years with TOF or pulmonary stenosis and primary procedure TOF surgical repair or palliation. Procedural frequencies were examined by epoch. Demographics, clinical variables, and outcomes were compared between the initial palliation and primary repair groups. Among those operated on at 0 to 60 days of age, variation in palliation rates across hospitals was assessed. RESULTS: The 12,157 operations included 11,307 repairs (93.0%) and 850 palliations (7.0%); 68.5% of all palliations were modified Blalock-Taussig-Thomas shunts. Of 1105 operations on neonates, 45.4% (502) were palliations. Among neonates, palliations declined from 49.0% (331 of 675) in epoch 1 (2010-2015) to 39.8% (171 of 430) in epoch 2 (2016-2020; P = .0026). Overall, the most prevalent repair technique (5196 of 11,307; 46.0%) was ventriculotomy with transanular patch, which was also used in 520 of 894 (58.2%) of repairs after previous cardiac operations. Patients undergoing initial palliation demonstrated more preoperative STS risk factors (50.1% vs 24.3% respectively; P < .0001) and more major morbidity and mortality than patients undergoing primary repair (21.2% vs 7.46%; P < .0001). In the 0- to 60-day age group, risk factor-adjusted palliation rates across centers varied considerably, with 32 of 99 centers performing significantly more or significantly fewer palliations than predicted on the basis of their case mix. CONCLUSIONS: Surgical palliation rates have decreased across all age groups despite increasing prevalence of risk factors. Ventriculotomy with transanular patch remains the most prevalent repair type. The considerable center-level variation in rates of palliation was not completely explained by case mix.

The impact of a statewide payment reform on transcatheter aortic valve replacement (TAVR) utilization and readmissions.

BACKGROUND: Transcatheter aortic valve replacement (TAVR) is an increasingly used but relatively expensive procedure with substantial associated readmission rates. It is unknown how cost-constrictive payment reform measures, such as Maryland's All Payer Model, impact TAVR utilization given its relative expense. This study investigated the impact of Maryland's All Payer Model on TAVR utilization and readmissions among Maryland Medicare beneficiaries. METHODS: This was a quasi-experimental investigation of Maryland Medicare patients undergoing TAVR between 2012 and 2018. New Jersey data were used for comparison. Longitudinal interrupted time series analyses were used to study TAVR utilization and difference-in-differences analyses were used to investigate post-TAVR readmissions. RESULTS: During the first year of payment reform (2014), TAVR utilization among Maryland Medicare beneficiaries dropped by 8% (95% confidence interval [CI]: -9.2% to -7.1%; p < 0.001), with no concomitant change in TAVR utilization in New Jersey (0.2%, 95% CI: 0%-1%, p = 0.09). Longitudinally, however, the All Payer Model did not impact TAVR utilization in Maryland compared to New Jersey. Difference-in-differences analyses demonstrated that implementation of the All Payer Model was not associated with significantly greater declines in 30-day post-TAVR readmissions in Maryland versus New Jersey (-2.1%; 95% CI: -5.2% to 0.9%; p =0.1). CONCLUSIONS: Maryland's All Payer Model resulted in an immediate decline in TAVR utilization, likely a result of hospitals adjusting to global budgeting. However, beyond this transition period, this cost-constrictive reform measure did not limit Maryland TAVR utilization. In addition, the All Payer Model did not reduce post-TAVR 30-day readmissions. These findings may help inform expansion of globally budgeted healthcare payment structures.

Multiple Arterial Graft Use in Coronary Artery Bypass Surgery: Surgeon Perspective vs Practice.

BACKGROUND: Despite supportive evidence and guidelines, the use of multiple arterial grafts (MAGs) in coronary artery bypass grafting remains low. We sought to determine surgeon perception of personal MAG use and compare this with actual MAG use. METHODS: We conducted a statewide surgeon survey of MAG use, presence of a hospital MAG protocol, and barriers for MAG use, with a response rate of 78% (n = 25). Surgeon survey responses were compared with actual Society of Thoracic Surgeons patient data from January 1, 2017, to December 31, 2020 using χ2 or Fisher's exact tests. RESULTS: Of 5299 patients who had first-time, nonemergent, isolated coronary artery bypass grafting (≥2 grafts) by responding surgeons, 16% received MAG (n = 825). MAG use in patients whose surgeons self-designated as "routine" MAG users was 21% vs 7% for "nonroutine" users. Surgeons with a hospital protocol for MAG use utilized MAG more often (18% vs 14%, P = .001). Surgeons who were unconvinced by the data on the benefits of MAGs used MAGs in 11% vs 22% in surgeons who were convinced. MAG use increased over time, particularly from before to after the survey (13.1% vs 30.5%, P < .001). CONCLUSIONS: Although MAG use increased over time, barriers to routine use remain. In surgeons who reported routine use, only 21% of their patients received MAGs. Hospital protocols, education, and increased awareness may reduce barriers to use and encourage evidence-based clinical practice.

Hospital variability in modifiable factors driving coronary artery bypass charges.

OBJECTIVE: Coronary artery bypass grafting is associated with significant interhospital variability in charges. Drivers of hospital charge variability remain elusive. We identified modifiable factors associated with statewide interhospital variability in hospital charges for coronary artery bypass grafting. METHODS: Charge data were used as a surrogate for cost. Society of Thoracic Surgeons data from Maryland institutions and charge data from the Maryland Health Care Commission were linked to characterize interhospital charge variability for coronary artery bypass grafting. Multivariable linear regression was used to identify perioperative factors independently related to coronary artery bypass grafting charges. Of the factors independently associated with charges, we analyzed which factors varied between hospitals. RESULTS: A total of 10,337 patients underwent isolated coronary artery bypass grafting at 9 Maryland hospitals from 2012 to 2016, of whom 7532 patients were available for analyses. Mean normalized charges for isolated coronary artery bypass grafting varied significantly among hospitals, ranging from $30,000 to $57,000 (P < .001). Longer preoperative length of stay, operating room time, and major postoperative morbidity including stroke, renal failure, prolonged ventilation, reoperation, and deep sternal wound infection were associated with greater hospital charges. Incidence of major postoperative events, except stroke and deep sternal wound infection, was variable between hospitals. In a univariate linear regression model, patient risk profile only accounted for approximately 10% of statistical variance in charges. CONCLUSIONS: There is significant charge variability for coronary artery bypass grafting among hospitals within the same state. By targeting variation in preoperative length of stay, operating room time, postoperative renal failure, prolonged ventilation, and reoperation, cardiac surgery programs can realize cost savings while improving quality of care for this resource-intense patient population.

Impact of Preoperative Hematocrit, Body Mass Index, and Red Cell Mass on Allogeneic Blood Product Usage in Adult Cardiac Surgical Patients: Report From a Statewide Quality Initiative.

OBJECTIVE: The study aims were to evaluate current blood transfusion practice in cardiac surgical patients and to explore associations between preoperative anemia, body mass index (BMI), red blood cell (RBC) mass, and allogeneic transfusion. DESIGN: Multicenter retrospective study. SETTING: Academic and non-academic centers. PARTICIPANTS AND INTERVENTIONS: After Institutional Review Board approval, 26,499 patients who underwent coronary artery bypass grafting ± valve replacement/repair between 2011 and 2019 were included from the Maryland Cardiac Surgery Quality Initiative database. Patients were stratified into BMI categories (<25, 25 to <30, and ≥30 kg/m2), and a multivariable logistic regression model was fit to determine if preoperative hematocrit, BMI, and RBC mass were associated independently with allogeneic transfusion. RESULTS: Preoperative anemia was found in 55.4%, and any transfusion was administered to 49.3% of the entire cohort. Females and older patients had lower BMI and RBC mass. Increased RBC and cryoprecipitate transfusions occurred more frequently after surgery in the lower BMI group. After adjustments, increased transfusion was associated with a BMI <25 relative to a BMI ≥30 at an odds ratio (OR) of 1.26 (95% confidence interval [CI]: 1.08-1.39). For each 1% increase in preoperative hematocrit, transfusion was decreased by 9% (OR: 0.91; 95% CI: 0.90-0.92). For every 500 mL increase in RBC mass, there was a 43% reduction of transfusion (OR: 0.57; 95% CI: 0.55-0.58). CONCLUSIONS: Transfusion probability modeling based on calculated RBC mass eliminated sex differences in transfusion risk based on preoperative hematocrit, and may better delineate which patients may benefit from more rigorous perioperative blood conservation strategy.

Causal determinants of postoperative length of stay in cardiac surgery using causal graphical learning.

OBJECTIVE: We aimed to learn the causal determinants of postoperative length of stay in cardiac surgery patients undergoing isolated coronary artery bypass grafting or aortic valve replacement surgery. METHODS: For patients undergoing isolated coronary artery bypass grafting or isolated aortic valve replacement surgeries between 2011 and 2016, we used causal graphical modeling on electronic health record data. The Fast Causal Inference (FCI) algorithm from the Tetrad software was used on data to estimate a Partial Ancestral Graph (PAG) depicting direct and indirect causes of postoperative length of stay, given background clinical knowledge. Then, we used the latent variable intervention-calculus when the directed acyclic graph is absent (LV-IDA) algorithm to estimate strengths of causal effects of interest. Finally, we ran a linear regression for postoperative length of stay to contrast statistical associations with what was learned by our causal analysis. RESULTS: In our cohort of 2610 patients, the mean postoperative length of stay was 219 hours compared with the Society of Thoracic Surgeons 2016 national mean postoperative length of stay of approximately 168 hours. Most variables that clinicians believe to be predictors of postoperative length of stay were found to be causes, but some were direct (eg, age, diabetes, hematocrit, total operating time, and postoperative complications), and others were indirect (including gender, race, and operating surgeon). The strongest average causal effects on postoperative length of stay were exhibited by preoperative dialysis (209 hours); neuro-, pulmonary-, and infection-related postoperative complications (315 hours, 89 hours, and 131 hours, respectively); reintubation (61 hours); extubation in operating room (-47 hours); and total operating room duration (48 hours). Linear regression coefficients diverged from causal effects in magnitude (eg, dialysis) and direction (eg, crossclamp time). CONCLUSIONS: By using retrospective electronic health record data and background clinical knowledge, causal graphical modeling retrieved direct and indirect causes of postoperative length of stay and their relative strengths. These insights will be useful in designing clinical protocols and targeting improvements in patient management.

Early Reexploration for Bleeding Is Associated With Improved Outcome in Cardiac Surgery.

BACKGROUND: Reexploration after cardiac surgery, most frequently for bleeding, is a quality metric used to assess surgical performance. This may cause surgeons to delay return to the operating room in favor of attempting nonoperative management. This study investigated the impact of the timing of reexploration on morbidity and mortality. METHODS: This study was a single-institution retrospective review of all adult cardiac surgery patients from July 2010 to June 2020. Time to reexploration was assessed, and outcomes were compared across increasing time intervals. Reported bleeding sites were classified into 5 groups, and bleeding rate (chest tube output) was compared across bleeding sites. Univariable analysis was performed using the Fisher exact and Kruskal-Wallis tests. Multivariable logistic regression models were used for risk-adjusted analyses. RESULTS: Of 10 070 eligible patients, 251 (2.5%) required reexploration for postoperative bleeding. The most common site of bleeding was "any suture line" (n = 70; 28%). Interestingly, in 30% of cases (n = 75) "no active bleeding" site was reported. The highest rate of bleeding (mL/h) was observed in the "any mediastinal structure" group (median, 450; interquartile range [IQR], 185, 8878), and the lowest rate was noted in the "no active bleeding" group (median, 151.2; IQR, 102, 270). Both morbidity rates (0-4 hours, 12.3% vs 25-48 hours, 37.5%; P = .001) and mortality rates (0-4 hours, 3.1% vs 25-48 hours, 43.8%; P = .001) escalated significantly with increasing time to reexploration. CONCLUSIONS: Delayed reexploration for bleeding after cardiac surgery is associated with increased risk for morbidity and mortality. Early surgical intervention, particularly within 4 hours, may improve outcomes. Implications from using reoperation as a performance metric may lead to unnecessary delay and patient harm.

Association Between Early Speech-Language Pathology Consultation and Pneumonia After Cardiac Surgery.

PURPOSE: Patients undergoing cardiac surgery are reported to be at higher risk for oropharyngeal dysphagia and aspiration, which may predispose them to respiratory complications such as pneumonia. Speech-language pathology consultation facilitates early identification of swallowing difficulties providing appropriate and timely interventions during the postoperative period. This study explores the association between pneumonia and timing of speech-language pathology order entry and evaluation following cardiac surgery. METHOD: A retrospective study was performed on adults who underwent cardiac surgery in a tertiary care center, from July 2016 through December 2019. Patients with preexisting tracheostomy upon admission for cardiac surgery were excluded. The medical records of patients who had speech-language pathology consultation orders for swallowing concerns were analyzed in order to compare the timing of speech-language pathology order entry, completion of speech-language pathology evaluation, and incidence of pneumonia during hospitalization following cardiac surgery. RESULTS: During the study period, 3,168 patients underwent cardiac surgery, of which 2,864 patients met the inclusion criteria. Speech-language pathology was ordered for 473 cases (16.5%), and clinical swallow evaluation (CSE) was completed by speech-language pathology in 419 patients (88.6%), of which 309 patients were suspected to have dysphagia (73.7%). Among the 2,391 patients without speech-language pathology consultation, pneumonia was reported in 34 patients (1.42%). Pneumonia was reported in 53 patients in the speech-language pathology cohort, of which 43 patients (13.9%) were suspected to have dysphagia. Patients with pneumonia had significantly longer median time (20.0 hr, range: 4.9-26.7) from speech-language pathology orders to completion of CSE, compared to those without pneumonia (13.2 hr, range: 3.2-22.4, p = .025). There was no significant difference in the median time from extubation to speech-language pathology consultation order time in patients with pneumonia versus those without pneumonia. Patients with pneumonia were observed to have prolonged, although not statistically significant, median time from extubation to CSE (70.4 hr, range: 21.2-215) compared to those without pneumonia (42.2 hr, range: 19.5-105.8, p = .066). CONCLUSIONS: Patients without pneumonia in the postoperative period were observed to have shorter median time from extubation to speech-language pathology evaluation. Future studies are needed to further understand the impact of early speech-language pathology consultation and incidence of pneumonia in this population.

Heparin-Induced Thrombocytopenia After Cardiac Surgery-A Statewide Review of Health Care Utilization.

BACKGROUND: Despite its severe consequences, clinical and economic impacts of heparin-induced thrombocytopenia (HIT) after cardiac operations have not been well characterized. This study assessed statewide incidence, outcomes, and resource consumption associated with HIT after cardiac operations. METHODS: This was a retrospective investigation of cardiac surgery patients using the Maryland Health Services Cost Review Commission's database from 2012 to 2020. Health care costs, utilization, and outcomes for those who experienced postoperative HIT were compared with propensity score-matched controls. RESULTS: Of 33 583 cardiac surgery patients, 184 (0.55%) were diagnosed with postoperative HIT. Compared with non-HIT patients, HIT patients were significantly more likely to be in the oldest age group (>80 years; P < .001) and to have greater severity of illness at admission (P < .001). HIT was associated with a longer hospitalization (21 vs 7 days; P < .001), greater mortality (13.6% vs 2.3%; P < .001), and greater hospital charges ($123 160 vs $45 303; P < .001), even after propensity score matching. Readmission rates were not significantly different, however, and readmission hospital charges did not significantly differ between HIT and non-HIT patients. CONCLUSIONS: In addition to worse outcomes, HIT was associated with higher costs during index admissions but not during readmissions of cardiac surgery patients. Strategies to minimize HIT could yield better outcomes and reduced costs, particularly relevant for health care systems seeking improved value-based care while reducing unnecessary hospitalizations.

Number and Type of Blood Products Are Negatively Associated With Outcomes After Cardiac Surgery.

BACKGROUND: The association between blood transfusion and adverse outcome is documented in cardiac surgery. However, the incremental significance of each unit transfused, whether red blood cell (RBC) or non-RBC, is uncertain. This study examined the relationship of patient outcomes with the type and number of blood product units transfused. METHODS: Statewide data from 24 082 adult cardiac surgery patients were included. The relationship with blood transfusion was assessed for morbidity and 30-day mortality using total number of RBC and non-RBC units transfused, specific type of non-RBC units, and different combinations of transfusion (only RBC, only non-RBC, RBC + non-RBC). Multivariable logistic regressions examined these associations. RESULTS: Median age was 66 years (30% female patients), and 51% of patients received a transfusion (31%-66% across hospitals). Risk-adjusted analyses found each blood product unit was associated with 9%, 7%, and 4% greater odds for 30-day mortality, major morbidity, and minor morbidity, respectively (all P < .001). Odds for 30-day mortality were 13% greater with each RBC unit (P < .001) and 6% greater for each non-RBC unit (P < .001). Each unit of fresh frozen plasma (P < .001) and platelets (P < .001) increased the odds for 30-day mortality, but no effect was found for cryoprecipitate (P = .725). Odds for 30-day mortality were lower for non-RBC-only (odds ratio, 0.52; P = .030) and greater for RBC + non-RBC (odds ratio, 2.98; P < .001) compared with RBC-only transfusion. CONCLUSIONS: Independent of center variability on transfusion methods, each additional unit transfused was associated with increased odds for complications, with RBC transfusion carrying greater risk compared with non-RBC. Comprehensive evidence-based clinical approaches and coordination are needed to guide each blood transfusion event after cardiac surgery.

Leveraging Machine Learning to Predict 30-Day Hospital Readmission After Cardiac Surgery.

BACKGROUND: Hospital readmission within 30 days of discharge is a well-studied outcome. Predicting readmission after cardiac surgery, however, is notoriously challenging; the best-performing models in the literature have areas under the curve around .65. A reliable predictive model would enable clinicians to identify patients at risk for readmission and to develop prevention strategies. METHODS: We analyzed The Society of Thoracic Surgeons (STS) Adult Cardiac Surgery Database at our institution, augmented with electronic medical record data. Predictors included demographics, preoperative comorbidities, proxies for intraoperative risk, indicators of postoperative complications, and time series-derived variables. We trained several machine learning models, evaluating each on a held-out test set. RESULTS: Our analysis cohort consisted of 4924 cases from 2011 to 2016. Of those, 723 (14.7%) were readmitted within 30 days of discharge. Our models included 141 STS-derived and 24 electronic medical records-derived variables. A random forest model performed best, with test area under the curve 0.76 (95% confidence interval, 0.73 to 0.79). Using exclusively preoperative variables, as in STS calculated risk scores, degraded the area under the curve, to 0.64 (95% confidence interval, 0.60 to 0.68). Key predictors included length of stay (12.5 times more important than the average variable) and whether the patient was discharged to a rehabilitation facility (11.2 times). CONCLUSIONS: Our approach, augmenting STS variables with electronic medical records data and using flexible machine learning modeling, yielded state-of-the-art performance for predicting 30-day readmission. Separately, the importance of variables not directly related to inpatient care, such as discharge location, amplifies questions about the efficacy of assessing care quality by readmissions.

Trends and three-year outcomes of hepatitis C virus-viremic donor heart transplant for hepatitis C virus-seronegative recipients.

Objective: Heart transplants (HTs) from hepatitis C virus (HCV)-viremic donors to HCV-seronegative recipients (HCV D+/R-) have good 6-month outcomes, but practice uptake and long-term outcomes overall and among candidates on mechanical circulatory support (MCS) have yet to be established. Methods: Using the Scientific Registry of Transplant Recipients, we identified US adult HCV-seronegative HT recipients (R-) from 2015 to 2021. We classified donors as HCV-seronegative (D-) or HCV-viremic (D+). We used multivariable regression to compare post-HT extracorporeal membranous oxygenation, dialysis, pacemaker, acute rejection, and risk of post-HT mortality between HCV D+/R- and HCV D-/R-. Models were adjusted for donor, recipient, and transplant characteristics and center HT volume. We performed subgroup analyses of recipients bridged with MCS. Results: From 2015 to 2021, the number of HCV D+/R- HT increased from 1 to 181 and the number of centers performing HCV D+/R- HT increased from 1 to 60. Compared with HCV D-/R- recipients, HCV D+/R- versus D-/R- recipients overall and among patients bridged with MCS had similar odds of post-HT extracorporeal membranous oxygenation, dialysis, pacemaker, and acute rejection; and mortality risk at 30 days, 1 year, and 3 years (all P > .05). High center HT volume but not HCV D+/R- volume (<5 vs >5 in any year) was associated with lower mortality for HCV D+/R- HT. Conclusions: HCV D+/R- and D-/R- HT have similar outcomes at 3 years' posttransplant. These results underscore the opportunity provided by HCV D+/R- HT, including among the growing population bridged with MCS, and the potential benefit of further expanding use of HCV+ allografts.

Measures to Increase Use of Multiple Arterial Grafts for Isolated Coronary Artery Bypass Grafting.

BACKGROUND: Use of multiple arterial grafts (MAGs) provides superior patency and long-term survival benefit compared with venous grafts during coronary artery bypass grafting (CABG). However, MAGs are used infrequently for CABG. We hypothesized that specific measures introduced at our institution would lead to an increase in the use of MAGs. STUDY DESIGN: Use of MAGs before and after introduction of bundled measures was compared. Measures included increased education in arterial graft harvesting, inclusion as a quality metric, and hiring of surgeon champions. Patients younger than 70 years who underwent first time, isolated CABG using at least 1 arterial graft were included. Number and type of grafts used were compared between time periods using chi-square test. Secondary outcomes included postoperative complications. Complications were compared between time periods, as well as between MAG and non-MAG recipients before and after propensity score matching using Fisher exact test and univariate logistic regression. Multivariable logistic regression was used to determine patient characteristics associated with MAG use. RESULTS: There were 2,169 patients included from 2012 to 2019. MAG use increased significantly after introduction of measures (21.1% to 41.9%; p < 0.001). Radial artery use with an internal mammary artery (0.3% to 16%; p < 0.001) and the use of triple arterial grafts increased significantly (0% to 2.4%; p < 0.001). MAG use in the entire cohort was associated with decreased 30-day mortality and postoperative cardiac arrest that was not significant after propensity matching. CONCLUSIONS: A programmatic emphasis on the use of MAGs for CABG is an effective method to increase its use.

Association of Heparin Dose, Route, Timing, and Duration With Heparin-Induced Thrombocytopenia.

BACKGROUND: The prevalence of heparin-induced thrombocytopenia (HIT) varies by population and the type and duration of heparinoid exposure; however, the association with unfractionated heparin (UFH) dose, route, timing, and duration has not been evaluated in cardiac surgery patients. METHODS: A retrospective case-control study matched HIT-positive adult cardiac surgery patients (positive platelet factor 4 immunoglobulin G and serotonin release assays) 1:1 with HIT-negative controls. Total UFH dose, route, timing, and duration were compared between groups. RESULTS: The study included 124 patients, 92 male (74%), with mean age of 65 ± 11 years. Significantly more HIT-positive patients received intravenous UFH preoperatively or postoperatively compared with patients without HIT (55 [88.7%] vs 23 [37.1%]; P < .001). There were no significant differences regarding intraoperative or subcutaneous UFH dose or duration. When controlling for obesity and cardiopulmonary bypass duration using multivariable conditional logistic regression, the odds of HIT were increased 10-fold in patients who received preoperative or postoperative intravenous UFH continuous infusion (odds ratio 10.2, 95% confidence interval, 3.1 to 33.7; P < .001). Receiver-operating characteristic curves demonstrated that receiving preoperative or postoperative intravenous UFH infusion total dose greater than 32,000 units (sensitivity 82%, specificity 74%, area under the curve 0.78) or longer than 7 hours (sensitivity 87%, specificity 68%, area under the curve 0.77) was associated with HIT. CONCLUSIONS: Odds of HIT were increased 10-fold in adult cardiac surgery patients receiving preoperative or postoperative intravenous UFH infusion. Intraoperative UFH dose and subcutaneous route were not associated with HIT. Future study should evaluate incorporation of intravenous UFH administration, dose, and duration in HIT scoring tools for cardiac surgery patients.

Clinical Practice Variation and Outcomes for Stanford Type A Aortic Dissection Repair Surgery in Maryland: Report from a Statewide Quality Initiative.

BACKGROUND: Stanford Type A aortic dissection repair surgery is associated with high mortality and clinical practice remains variable among hospitals. Few studies have examined statewide practice variation. METHODS: Patients who had Stanford Type A aortic dissection repair surgery in Maryland between July 1, 2014 and June 30, 2018 were identified using the Maryland Cardiac Surgery Quality Initiative (MCSQI) database. Patient demographics, comorbidities, surgery details, and outcomes were compared between hospitals. We also explored the impact of arterial cannulation site and brain protection technique on outcome. RESULTS: A total of 233 patients were included from eight hospitals during the study period. Seventy-six percent of surgeries were done in two high-volume hospitals (≥10 cases per year), while the remaining 24% were done in low-volume hospitals. Operative mortality was 12.0% and varied between 0 and 25.0% depending on the hospital. Variables that differed significantly between hospitals included patient age, the percentage of patients in shock, left ventricular ejection fraction, creatinine level, arterial cannulation site, brain protection technique, tobacco use, and intraoperative blood transfusion. The percentage of patients who underwent aortic valve repair or replacement procedures differed significantly between hospitals (p < 0.001), although the prevalence of moderate-to-severe aortic insufficiency was not significantly different (p = 0.14). There were no significant differences in clinical outcomes including mortality, renal failure, stroke, or gastrointestinal complications between hospitals or based on arterial cannulation site (all p > 0.05). Patients who had aortic cross-clamping or endovascualr repair had more embolic strokes when compared with patients who had hypothermic circulatory arrest (p = 0.03). CONCLUSION: There remains considerable practice variation in Stanford Type A aortic dissection repair surgery within Maryland including some modifiable factors such as intraoperative blood transfusion, arterial cannulation site, and brain protection technique. Continued efforts are needed within MCSQI and nationally to evaluate and employ the best practices for patients having acute aortic dissection repair surgery.