The Association of Oxygen Delivery and Transfusion on Cardiopulmonary Bypass with Acute Kidney Injury.

OBJECTIVES: To estimate whether the association of transfusion and acute kidney injury (AKI) has a threshold of oxygen delivery below which transfusion is beneficial but above which it is harmful. DESIGN: Retrospective study SETTING: Cardiovascular operating room and intensive care unit PARTICIPANTS: Patients undergoing cardiac surgery with continuous oxygen delivery monitoring during cardiopulmonary bypass INTERVENTIONS: None MEASUREMENTS AND MAIN RESULTS: Logistic regression was used to estimate the associations between oxygen delivery (mean, cumulative deficit, and bands of oxygen delivery), transfusion, and their interaction and AKI. A subgroup analysis of transfused and nontransfused patients with exact matching on cumulative oxygen deficit and time on bypass with adjustment for propensity to receive a transfusion using logistic regression. Nine hundred ninety-one of 4,203 patients developed AKI within 7 days. After adjustment for confounders, lower mean oxygen delivery (odds ratio [OR], 0.968; 95% confidence interval [CI], 0.949-0.988; p = 0.002) and transfusions (OR, 1.442; 95% CI, 1.077, 1.932; p = 0.014) were associated with increased odds of AKI by 7 days. As oxygen delivery decreased, the risk of AKI increased, with the slope of the OR steeper at <160 mL/m2/min. In the subgroup analysis, matched transfused patients were more likely than matched nontransfused patients to develop AKI (45% [n = 145] v 31% [n = 101]; p < 0.001). However, after propensity score adjustment, the difference was nonsignificant (OR, 1.181; 95% CI, 0.796-1.752; p = 0.406). CONCLUSIONS: We found a nonlinear relationship between oxygen delivery and AKI. We found no level of oxygen delivery at which transfusion was associated with a decreased risk of AKI.

Effect of Changing Estimated Glomerular Filtration Rate Formula on Sugammadex Use and Pulmonary Complications for African American and non-African American Patients.

BACKGROUND: Sugammadex is associated with fewer postoperative pulmonary complications than is neostigmine reversal of neuromuscular blockade. However, the Food and Drug Administration-approved package insert states that its use is "not recommended" in severe renal impairment, separately defined as creatinine clearance <30 mL/min. Recently, the formula for estimating glomerular filtration rate (GFR) was updated to remove the race variable. Compared to the prior formula, the new consensus equation lowers the estimated GFR for African American patients and raises it for everyone else. We sought to determine how this change could differently impact the use of sugammadex, and thus the rate of pulmonary complications, for both African American and non-African American patients. METHODS: We used Monte Carlo simulation models to estimate the difference in pulmonary complications that would be suffered by patients when the change in creatine clearance calculated from the estimated GFR (using the old race-based and new race-neutral Chronic Kidney Disease Epidemiology Collaboration formulas) crossed the 30 mL/min threshold, which would require a change in sugammadex or neostigmine use. RESULTS: We found that 0.22% (95% confidence interval 0.14%-0.36%) of African American patients' creatinine clearance would drop from above to below 30 mL/min making sugammadex not recommended and 0.19% (0.16%-0.22%) of non-African American patients would have creatinine clearance increase to >30 mL/min making sugammadex now recommended. Based on our model, we estimate that African American patients would suffer (count [95% confidence interval]) 3 [0.4-6] more pulmonary complications per 100,000 African American patients who received rocuronium or vecuronium through the change from sugammadex to neostigmine reversal to comply with labeling recommendations. Conversely, the same change in formulas would reduce the number of non-African American patients suffering pulmonary complications by 3 [2-4] per 100,000. CONCLUSIONS: The recent change in GFR formulas may potentially be associated with an increase in postoperative pulmonary complications in African American patients and a decrease in postoperative pulmonary complications in non-African American patients through GFR-driven changes in sugammadex use.

Mortality Associated With Proportionality of Secondary Mitral Regurgitation After Transcatheter Mitral Valve Repair: North American Mitraclip for Functional Mitral Regurgitation Registry.

The association, if any, between the effective regurgitant orifice area (EROA) to left ventricular end-diastolic volume (LVEDV) ratio and 1-year mortality is controversial in patients who undergo mitral transcatheter edge-to-edge repair (m-TEER) with the MitraClip system (Abbott Vascular, Santa Clara, CA). This study's objective was to determine the association between EROA/LVEDV and 1-year mortality in patients who undergo m-TEER with MitraClip. In patients with severe secondary (functional) mitral regurgitation (MR), we analyzed registry data from 11 centers using generalized linear models with the generalized estimating equations approach. We studied 525 patients with secondary MR who underwent m-TEER. Most patients were male (63%) and were New York Heart Association class III (61%) or IV (21%). Mitral regurgitation was caused by ischemic cardiomyopathy in 51% of patients. EROA/LVEDV values varied widely, with median = 0.19 mm2/ml, interquartile range [0.12,0.28] mm2/ml, and 187 patients (36%) had values <0.15 mm2/ml. Postprocedural mitral regurgitation severity was substantially alleviated, being 1+ or less in 74%, 2+ in 20%, 3+ in 4%, and 4+ in 2%; 1-year mortality was 22%. After adjustment for confounders, the logarithmic transformation (Ln) of EROA/LVEDV was associated with 1-year mortality (odds ratio 0.600, 95% confidence interval 0.386 to 0.933, p = 0.023). A higher Society of Thoracic Surgeons risk score was also associated with increased mortality. In conclusion, lower values of Ln(EROA/LVEDV) were associated with increased 1-year mortality in this multicenter registry. The slope of the association is steep at low values but gradually flattens as Ln(EROA/LVEDV) increases.

Characteristics and Outcomes of Obstetric Sepsis by Three Sets of Clinical Diagnostic Criteria: A Retrospective Study.

OBJECTIVE: Pregnancy-related mortality in the United States is the highest of all developed nations with a reported rate of 17 deaths per 100,000 live births in 2014 to 2017. Sepsis-related mortality is a major component of pregnancy-related mortality. Similar to nonpregnancy-related sepsis, the criteria for pregnancy-related sepsis are evolving. The purposes of this study were to compare three criteria for sepsis (Sepsis-2, Sepsis-3, California Maternal Quality Care Collaborative [CMQCC]) with one another and to determine patient outcomes using those three sets of criteria. STUDY DESIGN: Using the electronic medical record, we obtained granular data on all patients at University of Michigan Medical Center from July 10, 2009 to September 4, 2019 with suspected sepsis (blood cultures and administration of antibiotics) during pregnancy until the 42nd postpartum day. Agreement between the three criteria were assessed with kappa and shown by a Venn diagram. Groups were compared using standardized differences and chi square, rank sum, or independent t-tests. RESULTS: Of the 228 patients having sepsis by any criteria, 191 (83%) patients met the criteria for Sepsis-2, 131 (57%) for Sepsis-3, and 62 (27%) met criteria according to CMQCC. Agreement between the three criteria ranged from kappa = 0.13 (95% confidence interval [CI]: 0.09, 0.18) to kappa = 0.31 (95% CI: 0.23, 0.39). Patients who met CMQCC criteria tended to have more comorbidities and higher APACHE II (Acute Physiology And Chronic Health Evaluation) scores. Mortality (by 90 days) among the groups was low with 10 (4%) patients dying. Patients meeting criteria for CMQCC sepsis had higher mortality than the non-CMQCC patients with sepsis (10 vs. 2%, standardized difference = 0.31, p = 0.027). CONCLUSION: The agreement among Sepsis-2, Sepsis-3, and CMQCC diagnostic criteria is weak. CMQCC criteria identifies patients with sepsis at higher risk of death. KEY POINTS: · Agreements (kappa) between the three criteria are poor.. · CMQCC sepsis patients have more comorbidities.. · Endometritis was the most common cause of sepsis.. · CMQCC mortality was 10%; non-CMQCC mortality was 2%..

Postdischarge Survival After Sepsis: A Cohort Study.

BACKGROUND: After hospital discharge, patients who had sepsis have increased mortality. We sought to estimate factors associated with postdischarge mortality and how they vary with time after discharge. METHODS: This was a retrospective study of hospital survivors of sepsis using time-varying Cox proportional hazard models, which produce a baseline hazard ratio (HR) and a second number (δHR) that reflects the amount by which the baseline HR changes with time. RESULTS: Of the 32,244 patients who survived sepsis at hospital discharge, 13,565 patients (42%) died (mean ± standard deviation: 1.41 ± 1.87 years) after discharge from the index hospitalization, while 18,679 patients were still alive at follow-up (4.98 ± 2.86 years). The mortality rate decreased with time after discharge: approximately 8.7% of patients died during the first month after discharge, 1.1% of patients died during the 12th month after discharge, and 0.3%% died during the 60th month; after Kaplan-Meier analysis, survival was 91% (95% confidence interval [CI], 91%-92%) at 1 month, 76% (95% CI, 76%-77%) at 1 year, 57% (95% CI, 56%-58%) at 5 years, and 48% (95% CI, 47%-48%) at 10 years after discharge. Organ dysfunction at discharge was associated with worse survival. In particular, elevated urea nitrogen at discharge (HR, 1.10 per 10 mg/dL, 95% CI, 1.08-1.12, P < .001) was associated with increased mortality, but the HR decreased with time from discharge (δHR, 0.98 per 10 mg/dL per year, 95% CI, 0.98-0.99, P < .001). Higher hemoglobin levels were associated with lower mortality (HR, 0.92 per g/dL, 95% CI, 0.91-0.93, P < .001), but this association increased with increasing time after discharge (δHR, 1.02 per g/dL per year, 95% CI, 1.01-1.02, P < .001). Older age was associated with an increased risk of mortality (HR, 1.29 per decade of age, 95% CI, 1.27-1.31, P < .001) that grew with increasing time after discharge (δHR, 1.01 per year of follow-up per decade of age, 95% CI, 1.00-1.02, P < .001). Compared to private insurances Medicaid as primary insurance was associated with an increased risk of mortality (HR, 1.17, 95% CI, 1.10-1.25, P < .001) that did not change with time after discharge. In contrast, Medicare status was initially associated with a similar risk of mortality as private insurance at discharge (HR, 1), but was associated with greater risk as time after discharge increased (δHR, 1.04 per year of follow-up, 95% CI, 1.03-1.05, P < .001). CONCLUSIONS: Acute physiologic derangements and organ dysfunction were associated with postdischarge mortality with the associations decreasing over time.

Practice makes perfect? Institutional coronary artery bypass case volumes and outcomes.

OBJECTIVES: Older studies of coronary artery bypass grafting (CABG) institutional case volumes and outcomes reported conflicting results. We explored this association in the rapidly changing contemporary practice of American surgeons using the Society of Thoracic Surgeons (STS) Adult Cardiac Surgery Database. METHODS: The 2018-2019 isolated primary CABG experience in the STS Adult Cardiac Surgery Database was analysed (241 902 patients; 1014 hospitals; 2718 surgeons). Generalized Estimating Equations were used to estimate coefficients between CABG institutional case volumes and outcomes. The observed-to-expected ratios based on STS risk models were used to assess risk-adjusted operative mortality (OM), mortality/major morbidity (MM) and deep sternal wound infections (DSWI) as a function of institutional case volumes. RESULTS: The mean (standard deviation) OM, MM and DSWI rates were 2.1% (2.7), 11.1% (9.2) and 0.6% (0.5), respectively. The mean (standard deviation) institutional case volumes per study period was 239 (192); 23% and 9% of institutions performed <100 and >500 cases/study period, respectively. There was a weak negative correlation between expected mortality (R2 -0.0014), OM (R2 -0.0272), MM (R2 -0.1213) and DSWI (R2 -0.003) and institutional case volumes. CONCLUSIONS: CABG outcomes generally improve with increasing institutional case volumes. Given the large number of CABG cases performed nationally, even the documented weak correlation has the potential to appreciably decrease OM, MM and DSWI if cases are performed at higher volume institutions. Studies focusing on additional hospital and surgeon factors are warranted to further define quality improvement opportunities.

Differences between patients in whom physicians agree versus disagree about the preoperative diagnosis of heart failure.

STUDY OBJECTIVE: To quantify preoperative heart failure (HF) diagnostic agreement and identify characteristics of patients in whom physicians agreed versus disagreed about the diagnosis. DESIGN: Observational cohort study. SETTING: Patients undergoing major non-cardiac surgery at an academic center between 2015 and 2019. PATIENTS: 40,659 patients undergoing major non-cardiac surgery, among which a stratified subsample of 1018 patients with and without documented HF was reviewed. INTERVENTIONS: Via a panel of physicians frequently managing patients with HF (cardiologists, cardiac anesthesiologists, intensivists), detailed chart reviews were performed (two per patient; median review time 32 min per reviewer per patient) to render adjudicated HF diagnoses. MEASUREMENTS: Adjudicated diagnostic agreement measures (percent agreement, Krippendorf's alpha) and univariate comparisons (standardized differences) between patients in whom physicians agreed versus disagreed about the preoperative HF diagnosis. MAIN RESULTS: Among patients with documented HF, physicians agreed about the diagnosis in 80.0% of cases (consensus positive), disagreed in 13.8% (disagreement), and refuted the diagnosis in 6.3% (consensus negative). Conversely, among patients without documented HF, physicians agreed about the diagnosis in 88.0% (consensus negative), disagreed in 8.4% (disagreement), and refuted the diagnosis in 3.6% (consensus positive). The estimated agreement for the 40,659 cases was 91.1% (95% CI 88.3%-93.9%); Krippendorff's alpha was 0.77 (0.75-0.80). Compared to patients in whom physicians agreed about a HF diagnosis, patients in whom physicians disagreed exhibited fewer guideline-defined HF diagnostic criteria. CONCLUSIONS: Physicians usually agree about HF diagnoses adjudicated via chart review, although disagreement is not uncommon and may be partly explained by heterogeneous clinical presentations. Our findings inform preoperative screening processes by identifying patients whose characteristics contribute to physician disagreement via chart review. Clinical Trial Number / Registry URL: Not applicable.

Factors Associated With Initiation of Mechanical Ventilation in Patients With Sepsis: Retrospective Observational Study.

BACKGROUND: Patients with sepsis are at risk for mechanical ventilation. This study aimed to identify risk factors for initiation of mechanical ventilation in patients with sepsis and assess whether these factors varied with time. METHODS: Data from the electronic health record were used to model risk factors for initiation of mechanical ventilation after the onset of sepsis. A time-varying Cox model was used to study factors that varied with time. RESULTS: Of 35 020 patients who met sepsis criteria, 28 747 were eligible for inclusion. Mechanical ventilation was initiated within 30 days after sepsis onset in 3891 patients (13.5%). Factors that were independently associated with increased likelihood of receipt of mechanical ventilation were race (White: adjusted hazard ratio [HR], 1.59; 95% CI, 1.39-1.83; other/unknown: adjusted HR, 1.97; 95% CI, 1.54-2.52), systemic inflammatory response syndrome (adjusted HR [per point], 1.23; 95% CI, 1.17-1.28), Sequential Organ Failure Assessment score (adjusted HR [per point], 1.28; 95% CI, 1.26-1.31), and congestive heart failure (adjusted HR, 1.30; 95% CI, 1.17-1.45). Hazard ratios decreased with time for Sequential Organ Failure Assessment score and congestive heart failure and varied with time for 4 comorbidities and 3 culture results. CONCLUSIONS: The risk for mechanical ventilation associated with different factors varied with time after sepsis onset, increasing for some factors and decreasing for others. Through a better understanding of risk factors for initiation of mechanical ventilation in patients with sepsis, targeted interventions may be tailored to high-risk patients.

Outcomes of Sepsis in Patients With and Without HIV Infection: A Retrospective Study.

BACKGROUND: HIV infection is associated with increased infections. OBJECTIVES: To (1) compare patients with sepsis with and without HIV, (2) assess whether HIV is associated with mortality in sepsis, and (3) identify factors associated with mortality in patients with HIV and sepsis. METHODS: Patients who met Sepsis-3 criteria were studied. HIV infection was defined as administration of highly active antiretroviral therapy, a diagnosis of AIDS encoded by the International Classification of Diseases, or a positive HIV blood test result. Propensity scores were used to match patients with HIV to similar patients without HIV, and mortality was compared with χ2 tests. Logistic regression was used to determine factors independently associated with mortality. RESULTS: Sepsis developed in 34 673 patients without HIV and 326 patients with HIV. Of these, 323 (99%) patients with HIV were matched to similar patients without HIV. The 30-60- and 90-day mortality was 11%, 15%, and 17%, respectively, in patients with sepsis and HIV, which was similar to the 11% (P > .99), 15% (P > .99), and 16% (P = .83) in patients without HIV. Logistic regression to adjust for confounders showed that obesity (odds ratio, 0.12; 95% CI, 0.03-0.46; P = .002) and high total protein on admission (odds ratio, 0.71; 95% CI, 0.56-0.91; P = .007) were associated with lower mortality. Mechanical ventilation at sepsis onset, renal replacement therapy, positive blood culture, and platelet transfusion were associated with increased mortality. CONCLUSIONS: HIV infection was not associated with increased mortality in patients with sepsis.

Angiotensin II for the Treatment of Refractory Shock: A Matched Analysis.

OBJECTIVES: To determine if angiotensin II is associated with improved outcomes as measured by 30- and 90-day mortality as well as other secondary outcomes such as organ dysfunction and adverse events. DESIGN: Retrospective, matched analysis of patients receiving angiotensin II compared with both historical and concurrent controls receiving equivalent doses of nonangiotensin II vasopressors. SETTING: Multiple ICUs in a large, university-based hospital. PATIENTS: Eight hundred thirteen adult patients with shock admitted to an ICU and requiring vasopressor support. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Angiotensin II use had no association with the primary outcome of 30-day mortality (60% vs 56%; p = 0.292). The secondary outcome of 90-day mortality was also similar (65% vs 63%; p = 0.440) as were changes in Sequential Organ Failure Assessment scores over a 5-day monitoring period after enrollment. Angiotensin II was not associated with increased rates of kidney replacement therapy (odds ratio [OR], 1.39; 95% CI, 0.88-2.19; p = 0.158) or receipt of mechanical ventilation (OR, 1.50; 95% CI, 0.41-5.51; p = 0.539) after enrollment, and the rate of thrombotic events was similar between angiotensin II and control patients (OR, 1.02; 95% CI, 0.71-1.48; p = 0.912). CONCLUSIONS: In patients with severe shock, angiotensin II was not associated with improved mortality or organ dysfunction and was not associated with an increased rate of adverse events.

Long-term Outcomes and Anticoagulation in Mitral Valve Surgery-A Report From The Society of Thoracic Surgeons Database.

BACKGROUND: Anticoagulation after bioprosthetic mitral valve (MV) replacement (BMVR) and repair (MVrep) is controversial. We explore outcomes among BMVR and MVrep patients in The Society of Thoracic Surgeons Adult Cardiac Surgery Database based on discharge anticoagulation status. METHODS: BMVR and MVrep patients aged ≥65 years in The Society of Thoracic Surgeons Adult Cardiac Surgery Database were linked to the Centers for Medicare and Medicaid Services claims database. Long-term mortality, ischemic stroke, bleeding, and a composite of the primary end points were compared as a function of anticoagulation. Hazard ratios (HRs) were calculated using multivariable Cox regression. RESULTS: A total of 26,199 BMVR and MVrep patients were linked to the Centers for Medicare and Medicaid Services database; of these, 44%, 4%, and 52% were discharged on warfarin, non-vitamin K-dependent anticoagulant (NOAC), and no anticoagulation (no-AC; reference), respectively. Warfarin was associated with increased bleeding in the overall study cohort (HR, 1.38; 95% CI 1.26-1.52) and in the BMVR (HR, 1.32; 95% CI, 1.13-1.55) and MVrep subcohorts (HR, 1.42; 95% CI, 1.26-1.60). Warfarin was associated with decreased mortality only among BMVR patients (HR, 0.87; 95% CI, 0.79-0.96). Stroke and the composite outcome did not differ across cohorts with warfarin. NOAC use was associated with increased mortality (HR, 1.33; 95% CI 1.11-1.59), bleeding (HR, 1.37; 95% CI, 1.07-1.74), and the composite outcome (HR, 1.26; 95% CI, 1.08-1.47). CONCLUSIONS: Anticoagulation was used in fewer than half of mitral valve operations. In MVrep patients, warfarin was associated with increased bleeding and was not protective against stroke or mortality. In BMVR patients, warfarin was associated with a modest survival benefit, increased bleeding, and equivalent stroke risk. NOAC was associated with increased adverse outcomes.

Oxygen Delivery Thresholds During Cardiopulmonary Bypass and Risk for Acute Kidney Injury.

BACKGROUND: Postoperative acute kidney injury (AKI) in cardiac surgery patients is multifactorial and associated with low oxygen delivery (DO2) during cardiopulmonary bypass. METHODS: Cardiac surgical patients undergoing full cardiopulmonary bypass between May 1, 2016 and December 31, 2021 were included, whereas those on preoperative dialysis, undergoing circulatory arrest procedures, or lacking minute-to-minute physiologic data were excluded. A 5-minute running average of indexed DO2 (DO2i, mL/min/m2) was calculated ([pump flow] × [hemoglobin] × 1.36 [hemoglobin saturation] + 0.003 [arterial oxygen tension]/body surface area). AKI was defined using established Kidney Disease: Improving Global Outcomes criteria. The threshold of nadir DO2i on the effect of AKI was estimated using risk-adjusted Constrained Broken-Stick models. RESULTS: Postoperative AKI occurred among 1155 patients (29.4%), with 276 (7.0%) having stage 2 to 3 AKI. The median nadir DO2i was lower for those with (vs without) AKI (197.9 mL/min/m2 [interquartile range {IQR}, 166.3-233.2] vs 217.2 mL/min/m2 [IQR, 184.5-252.2], P < .001) and stage 2 to 3 AKI relative to stage 1 or none (186.9 mL/min/m2 [IQR, 160.1-220.5] vs 213.8 mL/min/m2 [IQR, 180.4-249.4]). In risk-adjusted analyses the estimated threshold for nadir DO2i was 231.2 mL/min/m2 (95% CI, 173.6-288.8) for any AKI and 103.3 (95% CI, 68.4-138.3) for stage 2 to 3 AKI. CONCLUSIONS: Decreasing nadir DO2i was associated with an increased risk of AKI. The identified nadir DO2i thresholds suggest management and treatment of nadir DO2i during cardiopulmonary bypass may decrease a patient's postoperative AKI risk.

Patient-, Clinician-, and Institution-level Variation in Inotrope Use for Cardiac Surgery: A Multicenter Observational Analysis.

BACKGROUND: Conflicting evidence exists regarding the risks and benefits of inotropic therapies during cardiac surgery, and the extent of variation in clinical practice remains understudied. Therefore, the authors sought to quantify patient-, anesthesiologist-, and hospital-related contributions to variation in inotrope use. METHODS: In this observational study, nonemergent adult cardiac surgeries using cardiopulmonary bypass were reviewed across a multicenter cohort of academic and community hospitals from 2014 to 2019. Patients who were moribund, receiving mechanical circulatory support, or receiving preoperative or home inotropes were excluded. The primary outcome was an inotrope infusion (epinephrine, dobutamine, milrinone, dopamine) administered for greater than 60 consecutive min intraoperatively or ongoing upon transport from the operating room. Institution-, clinician-, and patient-level variance components were studied. RESULTS: Among 51,085 cases across 611 attending anesthesiologists and 29 hospitals, 27,033 (52.9%) cases received at least one intraoperative inotrope, including 21,796 (42.7%) epinephrine, 6,360 (12.4%) milrinone, 2,000 (3.9%) dobutamine, and 602 (1.2%) dopamine (non-mutually exclusive). Variation in inotrope use was 22.6% attributable to the institution, 6.8% attributable to the primary attending anesthesiologist, and 70.6% attributable to the patient. The adjusted median odds ratio for the same patient receiving inotropes was 1.73 between 2 randomly selected clinicians and 3.55 between 2 randomly selected institutions. Factors most strongly associated with increased likelihood of inotrope use were institutional medical school affiliation (adjusted odds ratio, 6.2; 95% CI, 1.39 to 27.8), heart failure (adjusted odds ratio, 2.60; 95% CI, 2.46 to 2.76), pulmonary circulation disorder (adjusted odds ratio, 1.72; 95% CI, 1.58 to 1.87), loop diuretic home medication (adjusted odds ratio, 1.55; 95% CI, 1.42 to 1.69), Black race (adjusted odds ratio, 1.49; 95% CI, 1.32 to 1.68), and digoxin home medication (adjusted odds ratio, 1.48; 95% CI, 1.18 to 1.86). CONCLUSIONS: Variation in inotrope use during cardiac surgery is attributable to the institution and to the clinician, in addition to the patient. Variation across institutions and clinicians suggests a need for future quantitative and qualitative research to understand variation in inotrope use affecting outcomes and develop evidence-based, patient-centered inotrope therapies.

Multiarterial Coronary Artery Bypass Grafting Practice Patterns in the United States: Analysis of The Society of Thoracic Surgeons Adult Cardiac Surgery Database.

BACKGROUND: We aimed to elucidate current national multiarterial coronary bypass grafting practice patterns and assess perioperative outcomes. METHODS: Isolated primary nonemergent/nonsalvage coronary artery bypass grafting patients with at least 1 internal thoracic artery and 2 or more grafts in The Society of Thoracic Surgery Adult Cardiac Surgery Database (2018-2019) were divided into 3 cohorts: single-arterial, bilateral internal thoracic artery (BITA), and radial artery multiarterial grafting. Observed-to-expected ratios based on 2017 Society of Thoracic Surgery risk models were derived for 30-day perioperative mortality, composite major morbidity and mortality, and deep sternal wound infections for each grafting group overall and as a function of institutional multiarterial case volumes per study period: low (<10), intermediate (11-30), and high (>30). RESULTS: A total of 281,515 patients (BITA, 15,663 [5.6%]; radial, 23,905 [8.5%]) at 1013 centers showed distinct geographic grafting patterns: BITA and radial multiarterial grafting rates were lowest in the South (4% and 6%, respectively) and highest in the Northeast (9% and 11%, respectively). The median institutional number of BITA and radial cases per study period was 4 and 7, with only 14% and 21% of institutions performing >30 BITA and radial multiarterial cases per study period, respectively. The observed-to-expected mortality for single-arterial bypass grafting was similar to multiarterial: single-arterial, 1.00 (95% CI, 0.98-1.03); BITA, 0.98 (95% CI, 0.84-1.13; P = .711); and radial, 0.96 (95% CI, 0.86-1.07; P = .818). Observed-to-expected mortality and composite major morbidity and mortality were lower at high vs low multiarterial case-volume centers: 0.91 (95% CI, 0.75-1.08) vs 1.30 (95% CI, 0.89-1.79; P = .048) and 1.06 (95% CI, 0.99-1.13) vs 1.51 (95% CI, 1.32-1.71; P < .001), respectively, for BITA, and 0.82 (95% CI, 0.87-1.30) vs 1.67 (95% CI, 1.21-2.21; P < .001) and 0.91 (95% CI, 0.93-1.08) vs 1.42 (95% CI, 1.24-1.61; P < .001), respectively, for radial. CONCLUSIONS: Multiarterial bypass grafting remains underused and limited to select centers. Worse outcomes at low-volume BITA and radial institutions document a case-volume outcomes effect. Additional studies are warranted to improve multiarterial outcomes at low-volume institutions.

Perioperative Anemia and Transfusions and Late Mortality in Coronary Artery Bypass Patients.

BACKGROUND: Perioperative anemia and transfusions are associated with adverse operative outcomes after coronary artery bypass graft surgery (CABG). Their individual association with long-term outcomes is unclear. METHODS: Patients aged 65 years and older who had undergone CABG and were in The Society of Thoracic Surgeons (STS) Adult Cardiac Surgery Database (n = 504,596) from 2011 to 2018 were linked to Centers for Medicare and Medicaid Service data to assess long-term survival. The association of intraoperative anemia defined by intraoperative nadir hematocrit (nHct) and red blood cell (RBC) transfusions, and their interactions, on long-term mortality were assessed with Kaplan-Meier estimates and multivariable Cox regression. Restricted cubic splines were used to explore the association between nHct as a continuous variable and long-term mortality. RESULTS: 258,398 on-pump CABG STS Adult Cardiac Surgery Database patients surviving the perioperative period were linked to Centers for Medicare and Medicaid Service claims files. Per World Health Organization criteria, 41% had preoperative anemia. Mean intraoperative nHct was 24%; RBC transfusion rate was 43.7%. Univariable analysis associated both RBC transfusion and lower nHct with worse survival. Lower nHct was only marginally associated with risk-adjusted mortality: adjusted hazard ratio (AHR) 1.04 (95% CI, 1.01-1.06) and 1.07 (95% CI, 1.00-1.14) at nHct 20% and at nHct 14%, respectively. RBC transfusion was associated with significantly higher adjusted mortality irrespective of timing of transfusion: AHR intraoperative 1.21 (95% CI, 1.18-1.27); AHR postoperative 1.26 (95% CI, 1.22-1.30); AHR both 1.46 (95% CI, 1.40-1.52) and across all levels of nHct. RBC transfusion was not associated with improved survival at any level of nHct. CONCLUSIONS: Among Medicare CABG patients, RBC transfusions were associated with increased risk-adjusted late mortality across all levels of nHct whereas intraoperative anemia was only marginally so. Tolerance of lower intraoperative nHct than currently accepted may be preferable to transfusions.

Comparison of static and rolling logistic regression models on predicting invasive mechanical ventilation or death from COVID-19-A retrospective, multicentre study.

INTRODUCTION: COVID-19 virus has undergone mutations, and the introduction of vaccines and effective treatments have changed its clinical severity. We hypothesized that models that evolve may better predict invasive mechanical ventilation or death than do static models. METHODS: This retrospective study of adult patients with COVID-19 from six Michigan hospitals analysed 20 demographic, comorbid, vital sign and laboratory factors, one derived factor and nine factors representing changes in vital signs or laboratory values with time for their ability to predict death or invasive mechanical ventilation within the next 4, 8 or 24 h. Static logistic regression was constructed on the initial 300 patients and tested on the remaining 6741 patients. Rolling logistic regression was similarly constructed on the initial 300 patients, but then new patients were added, and older patients removed. Each new construction model was subsequently tested on the next patient. Static and rolling models were compared with receiver operator characteristic and precision-recall curves. RESULTS: Of the 7041 patients, 534 (7.6%) required invasive mechanical ventilation or died within 14 days of arrival. Rolling models improved discrimination (0.865 ± 0.010, 0.856 ± 0.007 and 0.843 ± 0.005 for the 4, 8 and 24-h models, respectively; all p < 0.001 compared with the static logistic regressions with 0.827 ± 0.011, 0.794 ± 0.012 and 0.735 ± 0.012, respectively). Similarly, the areas under the precision-recall curves improved from 0.006, 0.010 and 0.021 with the static models to 0.030, 0.045 and 0.076 for the 4-, 8- and 24-h rolling models, respectively, all p < 0.001. CONCLUSION: Rolling models with contemporaneous data maintained better metrics of performance than static models, which used older data.

Delayed Discharge From the Intensive Care Unit Is Associated With Longer Hospital Lengths of Stay.

OBJECTIVE: The study authors sought to determine if delayed discharge from the intensive care unit (ICU) secondary to a lack of floor beds led to longer postoperative hospital length of stay (LOS) or more hospital readmissions. DESIGN: A retrospective study comparing patients with delayed discharge from the ICU to patients without delayed discharge. SETTING: At a cardiovascular ICU in a tertiary care university hospital. PARTICIPANTS: A total of 5,777 patients that were ready for discharge from the ICU after recovering from cardiac surgery. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: The authors used linear regression to measure postoperative hospital LOS and logistic regression to measure hospital readmission in patients whose transfer out of the ICU was delayed at least overnight to patients who were transferred out the same day. There were 3,903 patients transferred to the stepdown unit on the same day as the transfer order and 1,874 patients were transferred on a subsequent day. The postoperative LOS was shorter in the no delay group (9 ± 9 v 11 ± 10 days, standardized difference = 0.162), whereas the stepdown unit stay was similar (6 ± 6 v 5 ± 6 days, standardized difference = 0.076). The readmission rates were 15% in the no delay group versus 14% in the delayed discharge group (standardized difference = 0.032). After adjustment, the authors found by linear regression that delayed discharge was associated with an increase (0.72 [95% CI 0.43-1.01] days, p < 0.001) in postoperative LOS but was not associated with readmission. CONCLUSIONS: The study authors found that patients who had their discharge from the ICU delayed had an increased hospital LOS but a similar rate of hospital readmission.

Factors associated with occurrence and severity of acute kidney injury in patients with Sepsis - A retrospective database study.

PURPOSE: Sepsis remains the most common cause of acute kidney injury (AKI) and is associated with a high mortality. This study aims to identify laboratory, clinical and demographic factors that are associated with the different stages of AKI in sepsis. METHODS: We studied patients >18 years who met Sepsis-3 criteria between July 10, 2009 and September 7, 2019 using ordinal logistic regression to determine the factors associated with different stages of AKI. Sensitivity analyses for development of any stage vs no AKI and, separately, the factors associated with receipt of kidney replacement therapy were also done. RESULTS: Of 31,228 patients meeting Sepsis-3 criteria, 4684 (15%) developed AKI. Of the AKI patients, 53% were KDIGO stage 1, 9% stage 2, and 37% stage 3, with 27% of AKI patients receiving kidney replacement therapy (Stage 3b). Several comorbidities, mechanical ventilation, and pre-sepsis creatinine levels were associated with AKI occurrence and severity. Positive blood culture was associated with a higher risk (OR 1.10 [1.06, 1.15], p < 0.001), while positive respiratory, urine, and wound cultures were associated with lower risks of developing AKI and with lower severity. CONCLUSION: Presepsis creatinine levels, mechanical ventilation, comorbidities, and positive blood cultures were associated with AKI.

Intraoperative blood collection without fluid replacement for cardiac surgery - A retrospective analysis.

Background: Transfusion rates in cardiac surgery are high. Aim: To determine if intraoperative autologous blood removal without volume replacement is associated with fewer homologous blood transfusions without increasing acute kidney injury. Setting and Design: Retrospective, comparative study. Materials and Methods: Adult patients undergoing cardiac surgery, excluding those who underwent ventricular assist device surgery, heart transplants, or cardiac surgery without cardiopulmonary bypass were excluded, who had 1-3 units of intraoperative autologous blood removal were compared to patients without blood removal for determination of volume replacement, vasopressor support, acute kidney injury, and transfusions. Results: Autologous blood removal was associated with fewer patients receiving homologous transfusions: intraoperative red cell transfusions fell from 75% (Control) to 48% (1 unit removed), 40% (2 units), and 30% (3 units), P < 0.001. Total intraoperative and postoperative homologous RBC units transfused were lower in the blood removal groups: median (interquartile range) 3 (1, 6) in Control patients and 0 (0, 2), 0 (0, 2) and 0 (0, 1) in the 1, 2, and 3 units removed groups, P < 0.001. Similarly, plasma, platelet, and cryoprecipitate transfusions decreased. After adjustment for confounders, increased amounts of autologous blood removal were associated with increased intravenous fluids, only when 2 units were removed, and trivially increased vasopressor use. However, it was not associated with acidosis or acute kidney injury. Conclusions: Intraoperative autologous blood removal without volume replacement of 1-3 units for later autologous transfusion is associated with decreased homologous transfusions without acidosis or acute kidney injury.