Increased glucose variability is associated with atrial fibrillation after coronary artery bypass.

BACKGROUND: Elevated preoperative hemoglobin A1c (HbA1c) is a predictor of poor outcomes following coronary artery bypass grafting (CABG), but the role of increased postoperative glucose variability (GV) is unknown. We hypothesized that short-term postoperative GV is associated with an increased risk of postoperative atrial fibrillation following isolated CABG. METHODS: Multicenter retrospective study of 2073 patients who underwent isolated CABG from January 2012 to March 2018. Postoperative GV in the first 24 hours was measured by standard deviation, coefficient of variation, and mean amplitude of glycemic excursions. Multivariate logistic regression assessed the independent association of GV with postoperative atrial fibrillation. RESULTS: A total of 2073 patients met the study criteria, and 446 patients (21.5%) developed postoperative atrial fibrillation. Using multivariate logistic regression to adjust for covariates, postoperative atrial fibrillation was associated with increased 24-hour GV (odds ratio [OR] = 1.16, 95% confidence interval [CI], 1.05-1.27, P < 0.01) and increased 24-hour mean glucose (OR = 1.14, 95% CI, 1.08-1.21, P < 0.01). Thus, for every 10% increase in 24-hour GV or 10 mg/dL increase in mean glucose, there was a 16% or 14% increased risk of postoperative atrial fibrillation respectively. CONCLUSIONS: Increased 24-hour GV and mean glucose are predictors of atrial fibrillation after CABG. Preoperative HbA1c is not a risk factor for postoperative atrial fibrillation after adjusting for postoperative mean glucose and GV. Further investigation is needed to determine the relationship between adherence to strict glucose control and adverse events following CABG.

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.

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.

Increased Glucose Variability Is Associated With Major Adverse Events After Coronary Artery Bypass.

BACKGROUND: Elevated preoperative hemoglobin A1c (HbA1c) is a predictor of poor outcomes after coronary artery bypass grafting (CABG), but the role of postoperative glucose variability (GV) is unknown. We hypothesized that short-term postoperative GV is associated with major adverse events (MAEs) after isolated CABG. METHODS: This retrospective study evaluated 2215 patients who underwent isolated CABG from January 2012 to March 2018 at 2 medical centers. Postoperative GV in the first 12 hours and 24 hours was measured by the SD, coefficient of variation, and mean amplitude of glycemic excursions. The primary outcome (MAEs) was the composite of postoperative cardiac arrest, pneumonia, renal failure, stroke, sepsis, reoperation, and 30-day mortality. Multivariate logistic regression assessed the independent association of GV with MAE. RESULTS: A total of 2215 patients met the study criteria, and an MAE developed in 260 patients (11.7%). High 12-hour and 24-hour postoperative GV were associated with elevated HbA1c, insulin-dependent diabetes, renal failure, and nonelective operation. Multivariate logistic regression analysis showed MAEs were associated with increased mean postoperative glucose in the first 12 hours (odds ratio [OR], 1.013; 95% confidence interval [CI], 1.008-1.018; P < .001), the first 24 hours (OR, 1.017; 95% CI, 1.010-1.024; P < .001), and 24-hour postoperative GV (OR, 1.22; 95% CI, 1.09-1.37; P < .001). MAEs were not associated with preoperative HbA1c or 12-hour postoperative GV. CONCLUSIONS: Increased 24-hour but not 12-hour postoperative GV after CABG is a predictor of poor outcomes. Preoperative HbA1c is not associated with MAEs after adjusting for postoperative mean glucose and GV.

Warm, beating heart aortic valve replacement in a sickle cell patient.

Patients with sickle cell abnormalities undergoing surgery are generally considered to be at greater risk for perioperative complications. We present a 25-year-old woman with sickle cell disease (SCD) and severe aortic insufficiency. A minimally invasive, warm, beating heart approach was adopted to try and minimize the risk of sickling due to cardiopulmonary bypass (CPB), low-flow states, cold cardioplegia and aortic cross-clamping. Compared to classical methods, we believe our technique further reduces the risk of systemic and organ hypothermia and thus, sickling.