Heybati, Kiyan

Purpose: Despite the 2022 American Heart Association/American College of Cardiology guidelines recommending cardiac rehabilitation (CR) after aortic dissection repair, both patient participation in CR and the associated clinical outcomes remain poorly understood. Methods: Adults (≥18 years of age) discharged alive following thoracic aortic dissection surgery across the Mayo Clinic Enterprise (January 2012 to November 2022), with follow-up until May 2024, were included (IRB #24-001141). Data were presented using summary statistics and logistic regression modeling. Results: A total of 186 patients were referred; 37% were female, and the median age was 64 (51, 73) years. Dissections were classified as type A (43%), type B (18%), or a combination, and 55% had residual dissection. Over half (53%) did not start CR, with older age (aOR = 0.97: 95% CI, 0.94 - 0.99; P = .003), family history of aortic dissections and/or aneurysms (aOR = 0.17: 95% CI, 0.04 - 0.54; P = .005), and tobacco use (aOR = 0.35: 95% CI, 0.13 - 0.91; P = .037) being associated with lower odds of enrollment. Of the 87 who enrolled, 34 did so at a Mayo Clinic facility. There were no complications, with no difference in adverse outcomes. Among those with evaluations at graduation from CR (n = 21), quality of life (Dartmouth index 16 [14, 19] vs 25 [22, 30]; P = .002) and 6-minute walk distance (488 [375, 531] vs 302 [235, 398] m; P = .001) improved. Conclusions: Following thoracic aortic dissection repair, CR significantly improved quality of life and functional capacity without adverse events. Further work is needed to improve enrollment and establish data-driven safety margins for exercise.

Background: Propofol is a first-line sedative for critically ill adults receiving invasive mechanical ventilation (IMV). However, it can contribute to hemodynamic instability, especially in the setting of intubation. The magnitude, timing, risk factors, and variability of sedation-associated mean arterial pressure (MAP) changes remain poorly characterized in ICU settings. Objectives: To quantify MAP changes following propofol sedation, identify risk factors for hemodynamic instability, and characterize associated interventions. Methods: We included adults (≥18 years old) across 11 ICUs in the Mayo Clinic Enterprise who required IMV and received ≥6 consecutive hours of propofol infusion between 05/05/2018 and 07/31/2024. The primary outcome was MAP change within 2-hours following sedation. Secondary outcomes included vasopressor use and hypotension (MAP ≤60 mmHg). Mixed-effects modeling was utilized to account for individual patient differences. The main model used a “neutral” adjustment, estimating a 5 mmHg MAP increase per 0.05 mcg/kg/min of norepinephrine equivalents, reduced to 3 mmHg per 0.05 mcg/kg/min after reaching a dose of 0.20 mcg/kg/min. Those on any vasopressors prior to propofol sedation initiation were analyzed separately. Results: Across 16,418 patients, 25.2% were on vasopressors before sedation initiation. Among the remaining 12,281 patients, 40.3% required vasopressors and 7.7% experienced hypotension within 2 hours of sedation ( Image 1 ). Post-intubation sedation was associated with a MAP reduction within the first 30 minutes (-6.58 mmHg; 95% CI: -6.85 to -6.32; P<0.001; Images 2 and 3 ). There was substantial inter-patient variability in both baseline MAP (9.5% variation attributable to between-patient differences) and MAP decline after sedation (40.9% between-patient differences). Higher SOFA scores (-0.31 mmHg per point), older age (-0.04 mmHg per year), and male sex (-0.47 mmHg) were associated with lower MAP. Patients with higher illness severity experienced progressively greater MAP changes over time (-0.20 mmHg per hour per increasing SOFA point; P<0.001). Conclusions: Propofol sedation is associated with clinically significant hemodynamic effects requiring intervention in the early post-intubation period. The marked inter-patient variability in hemodynamic responses highlights the importance of personalized management approaches. Risk stratification may help identify patients who could benefit from preemptive hemodynamic optimization.

OBJECTIVE: To identify distinct phenotypes of acute respiratory distress syndrome (ARDS) developing after hematopoietic cell transplantation (HCT), using routinely available clinical data at ICU admission. DESIGN: Multicenter retrospective cohort study using latent class analysis. SETTING: ICUs across three Mayo Clinic campuses (Minnesota, Florida, and Arizona). PATIENTS: A total of 166 adult patients who developed ARDS within 120 days following HCT (96 allogeneic, 70 autologous). INTERVENTION: None. MEASUREMENTS AND MAIN RESULTS: Model selection was based on multiple metrics including Bayesian information criteria, entropy, and Vuong-Lo-Mendell-Rubin Likelihood Ratio testing. A two-class model optimally described the cohort. Class 1 (n = 81) was characterized by worse hypoxemia (P/F ratio 157 vs. 210, p = 0.002), higher Pco 2 (41 vs. 36 mm Hg, p < 0.001), and higher bilirubin (1.4 vs. 0.9 mg/dL, p < 0.001) compared with class 2 (n = 85). Both classes included a mix of transplant types, transcending a simple autologous/allogeneic dichotomy, although class 1 had more allogeneic recipients (70.4% vs. 45.9%, p = 0.001). Although time-from-transplant was not a class-defining variable, class 1 occurred later after transplant (30.0 vs. 11.9 d, p < 0.001) with higher frequency of idiopathic pneumonia syndrome (14.8% vs. 2.4%, p = 0.004). Class 2 had more frequent neutropenia (leukocytes 0.4 vs. 5.9 × 109, p < 0.001) and higher frequency of peri-engraftment respiratory distress syndrome (29.4% vs. 9.9%, p = 0.005). Outcomes were significantly worse for class 1 (90-d mortality: 72.8% vs. 48.2%, p = 0.001). An exploratory parsimonious model had good classification accuracy (0.90) using just six variables: leukocyte count, platelet count, bilirubin, Pco 2, body mass index, and temperature. CONCLUSIONS: ARDS after HCT comprises two distinct phenotypes with distinct clinical characteristics and outcomes. These phenotypes align with recognized post-HCT lung injury syndromes and may reflect different underlying biological processes. This framework provides a foundation for investigating targeted therapeutic approaches.

IMPORTANCE: Propofol is a first-line sedative for adults receiving invasive mechanical ventilation (IMV). However, it can contribute to hemodynamic instability, especially during intubation. The magnitude, timing, risk factors, and variability of sedation-associated mean arterial pressure (MAP) changes remain poorly characterized in ICU settings. OBJECTIVES: To quantify MAP changes following propofol sedation, identify risk factors for hemodynamic instability, and characterize associated interventions. DESIGN: Retrospective cohort study. The primary outcome was MAP change within 2 hours following sedation. Secondary outcomes included vasopressor use and hypotension (MAP ≤ 60 mm Hg). Mixed-effects modeling was used to account for individual patient differences. SETTING AND PARTICIPANTS: Adults (≥ 18 yrs old) who required IMV and received greater than or equal to 6 consecutive hours of propofol infusion, between May 5th, 2018, and July 31st, 2024, in 11 ICUs across the Mayo Clinic, spanning 5 hospitals in 4 states. MAIN OUTCOMES AND MEASURES: The primary outcome was the change in MAP within 2 hours following the initiation of propofol-based sedation. RESULTS: Across 16,418 patients, 25.2% were on vasopressors before sedation initiation. Among the remaining 12,281 patients, 40.3% required vasopressors and 7.7% experienced hypotension within 2 hours of sedation. Propofol-based sedation was associated with a MAP reduction within the first 30 minutes (–6.58 mm Hg; 95% CI, –6.85 to –6.32; p < 0.001). There was substantial interpatient variability in both baseline MAP, and MAP decline after sedation (9.5 and 40.9% between-patient differences, respectively). Higher Sequential Organ Failure Assessment (SOFA) scores (–0.31 mm Hg/point), older age (–0.04 mm Hg/yr), and male sex (–0.47 mm Hg) were associated with lower MAP. Patients with higher illness severity experienced progressively greater MAP decline over time (–0.20 mm Hg/hr/SOFA point; p < 0.001). CONCLUSIONS AND RELEVANCE: Propofol-based sedation was associated with clinically significant hemodynamic effects requiring intervention in the early post-intubation period. The marked interpatient variability in hemodynamic responses highlights the importance of personalized management approaches, including risk stratification based on age, sex, and illness severity.

Machine-learning (ML) models have the potential to transform health care by enabling more personalized and data-driven clinical decision making. However, their successful implementation in clinical practice requires careful consideration of factors beyond predictive accuracy. We provide an overview of essential considerations for developing clinically applicable ML models, including methods for assessing and improving calibration, selecting appropriate decision thresholds, enhancing model explainability, identifying and mitigating bias, as well as methods for robust validation. We also discuss strategies for improving accessibility to ML models and performing real-world testing. Highlights This tutorial provides clinicians with a comprehensive guide to implementing machine-learning classification models in clinical practice. Key areas covered include model calibration, threshold selection, explainability, bias mitigation, validation, and real-world testing, all of which are essential for the clinical deployment of machine-learning models. Following these guidance can help clinicians bridge the gap between machine-learning model development and real-world application and enhance patient care outcomes.

Purpose: To develop and validate an explainable machine learning (ML) tool to help clinicians predict the risk of propofol-associated hypertriglyceridemia in critically ill patients receiving propofol sedation. Methods: Patients from 11 intensive care units (ICUs) across five Mayo Clinic hospitals were included if they met the following criteria: a) ≥ 18 years of age, b) received propofol infusion while on invasive mechanical ventilation for ≥24 h, and c) had a triglyceride level measured. The primary outcome was hypertriglyceridemia (triglyceride >400 mg/dL) onset within 10 days of propofol initiation. Both COVID-inclusive and COVID-independent modeling pipelines were developed to ensure applicability post-pandemic. Decision thresholds were chosen to maintain model sensitivity >80%. Nested leave-one-site-out cross-validation (LOSO-CV) was used to externally evaluate pipeline performance. Model explainability was assessed using permutation importance and SHapley Additive exPlanations (SHAP). Results: Among 3922 included patients, 769 (19.6%) developed propofol-associated hypertriglyceridemia, and 879 (22.4%) had COVID-19 at ICU admission. During nested LOSO-CV, the COVID-inclusive pipeline achieved an average AUC-ROC of 0.71 (95% confidence interval [CI] 0.70–0.72), while the COVID-independent pipeline achieved an average AUC-ROC of 0.69 (95% CI 0.68–0.70). Age, initial propofol dose, and BMI were the top three most important features in both models. Conclusion: We developed an explainable ML-based tool with acceptable predictive performance for assessing the risk of propofol-associated hypertriglyceridemia in ICU patients. This tool can aid clinicians in identifying at-risk patients to guide triglyceride monitoring and optimize sedative selection.

Abstract Rationale: Propofol can increase the risk of hypertriglyceridemia and subsequent pancreatitis in critically ill patients. It is unclear whether modifying or continuing sedation regimens in patients experiencing hypertriglyceridemia while on propofol infusion influences the development of adverse events such as acute pancreatitis. This study compared the clinical outcomes of patients receiving invasive mechanical ventilation (IMV) who had their propofol regimen modified versus continued following the detection of hypertriglyceridemia. Methods: A targeted trial emulation was conducted using retrospective data from 5 Mayo Clinic hospitals between 05/05/2018 and 06/30/2023. Inclusion criteria included: 1) receiving IMV and continuous propofol infusion for &gt;24 hours, 2) experiencing triglyceride level &gt;400 mg/dL while on propofol, and 3) still requiring IMV at 24-hours after hypertriglyceridemia onset. Patients were then categorized based on whether they had their propofol regimen modified (i.e., dose reduction by ≥50% or any reduction with alternative sedatives started) versus continued (no reduction or &lt;50% reduction without alternative sedative initiation). Outcomes included 30-day ventilator-free days, successful extubation, acute pancreatitis (determined by chart review, in-duplicate), ICU and hospital length of stay, 30- and 90-days alive and at home, as well as all-cause mortality. Analyses were conducted using stabilized inverse probability of treatment weights with adjustments for covariates selected a priori. Sensitivity analyses, where only benzodiazepines or benzodiazepines and ketamine were considered to be eligible alternative sedatives, were done. Results: During the study period, 728 patients were included, of whom 422 had their propofol regimen modified (Image). The two groups had similar demographics, comorbidities, and illness severity. We identified 14 cases of acute pancreatitis possibly attributable to propofol, with 9 cases in the modified and 5 cases in the continued regimen group (2.1% versus 1.6%; P=0.63). Following adjustment for covariates, there were no significant differences in any outcomes of interest. After censoring for mortality, there was no significant difference in the 30-day cumulative incidence of successful extubation when comparing those with their regimen modified versus continued (Hazard ratio [HR] 0.95; 95% confidence intervals [CI] 0.77 to 1.18; P=0.70). There was also no significant difference in the 90-day survival rate between the two groups (HR 0.89; 95% CI 0.71 to 1.11; P=0.34). These findings remained consistent upon sensitivity analyses. Conclusion: There were no differences in outcomes among patients who had their propofol regimens modified versus continued following the detection of hypertriglyceridemia. Further prospective investigations are needed to identify the optimal strategy for managing sedative regimens in this patient population.

Abstract RATIONALE Propofol is the first-line sedative for critically-ill, mechanically-ventilated patients, but it can increase serum triglyceride levels. Machine-learning (ML) offers a promising approach for individualized risk stratification of propofol-associated hypertriglyceridemia, enabling proactive triglyceride monitoring and sedation optimization. This study aims to develop and validate ML models to predict hypertriglyceridemia risks in critically-ill patients receiving propofol. METHODS We analyzed retrospective data from adult ICU patients on mechanical ventilation receiving continuous propofol infusion for ≥24 hours across four Mayo Clinic sites from May 2018 to June 2023. The primary outcome was hypertriglyceridemia, defined as serum triglycerides &gt;400 mg/dL within 10 days of starting propofol. Ten-fold cross-validation and leave-one-site-out nested cross-validation (LOSO-CV) were used for model tuning and external validation of our modeling process, respectively. Feature selection was conducted through a union of Boruta and least absolute shrinkage and selection operator (LASSO). While COVID status was a strong predictor of hypertriglyceridemia, we concurrently developed non-COVID models to ensure future relevance in non-pandemic settings. Six ML algorithms (logistic regression, support vector machines, random forests, LightGBM, XGBoost, and multilayer perceptrons) were tuned using Bayesian optimization to minimize cross-entropy loss. Classification thresholds were set to target sensitivity ≥80%. Model performance was evaluated using AUC-ROC, Brier score, sensitivity, and specificity. Models with the highest Youden's Index were designated the best-performing model. Model explainability was assessed using permutation importance and SHapley Additive exPlanations (SHAP). RESULTS We included 3922 eligible patients with triglyceride measurements. Of these, 3042 patients were COVID-negative and used for non-COVID modeling. The best-performing non-COVID models achieved an average AUC-ROC of 0.69 (95% confidence interval [CI] 0.68-0.70), Brier score of 0.12 (95% CI 0.09-0.14), sensitivity of 0.79 (95% CI 0.75-0.83), and specificity of 0.48 (95% CI 0.44-0.52) during LOSO-CV. The best-performing models that included COVID status achieved an average AUC-ROC of 0.71 (95% CI 0.70-0.72), Brier score of 0.13 (95% CI 0.10-0.16), sensitivity of 0.78 (95% CI 0.71-0.84), and specificity of 0.51 (95% CI 0.45 to 0.56) during LOSO-CV. The permutation importance results of the final non-COVID model are shown in the figure. CONCLUSION We have developed sensitive ML models for predicting hypertriglyceridemia risks in critically-ill patients receiving propofol. Although developed during the COVID-19 pandemic, the non-COVID models are more likely to have future relevance, and they have similar performance as models including COVID status. These models will be integrated into a web-based clinical calculator and undergo further validation in prospective studies.

Objectives: To determine associations between physician sex and use of postoperative healthcare resources among patients undergoing common surgeries in Ontario, Canada. Background: Prior studies have shown that patients of female physicians experience better outcomes and have lower healthcare costs compared with patients of male physicians. Understanding differences in resource utilization may offer insights into the care pathways and practice patterns contributing to these differences. Methods: We conducted a population-based, retrospective cohort study of adults (≥18 years of age) undergoing 1 of 25 common surgeries, between January 1, 2007, and December 31, 2019, in Ontario, Canada. The primary outcome was the utilization of one of the following: intensive care unit admission, other medical interventions (eg, tracheostomy, new dialysis starts, and home oxygen), and discharge care needs (eg inpatient rehab, long-term care, and home care use) within 30 days. The data were summarized using descriptive statistics and adjusted using multivariable generalized estimating equations. Results: This population-based study included 1,100,193 patients (61.8% female). Patients treated by male surgeons had higher use of postoperative resources versus those with female surgeons within 30 days (adjusted rate 33.1; 95% confidence interval [CI]: 28.0–39.2 versus 31.2; 95% CI: 25.8–37.7), 90 days, and 1 year. Consistent with these findings, following adjustment for patient, surgeon, procedural, and hospital characteristics, patients treated by male surgeons were significantly more likely to utilize postoperative resources within 30 days (adjusted odds ratio: 1.14; 95% CI: 1.03–1.27; P = 0.010) and at other time points. This difference was primarily driven by the higher use of home care among patients with a male versus female surgeon at all time points (30 days: adjusted odds ratio, 1.13; 95% CI: 1.05–1.21; P = 0.002). Conclusions: Patients with male surgeons had higher postoperative resource utilization when compared with those treated by female surgeons, which was almost entirely driven by the higher use of home care. Further mixed-methods investigation is needed to better understand other potentially relevant factors including surgical outcomes, individual patient preferences, and surgical team decision-making.

ABSTRACT Ventricular arrhythmias (VA), including ventricular tachycardia and fibrillation, are critical cardiac conditions that are often managed by catheter ablation among those unresponsive to pharmacologic therapy. The choice of anesthesia and sedation regimens for VA ablations may impact arrhythmia inducibility and hemodynamic stability, which can affect procedural success and complication rates. This systematic review and meta-analysis aimed to compare the efficacy and safety of sedation versus general anesthesia (GA) among patients undergoing VA ablation. The review was prospectively registered on PROSPERO (CRD42023441553). Database searches were conducted across five major databases from inception to March 9, 2024 to identify randomized trials or observational studies including adult patients undergoing ablations for VA. Screening and data extraction were completed in duplicate. Risk-of-bias assessments were conducted using ROBINS-I as all included studies were observational, and the quality of evidence was evaluated using the GRADE framework. Six observational studies (N = 16,435) were included. No significant differences were found between sedation and GA for total procedure time (MD: −14.16 minutes; 95%CI: −38.61 to 10.29 minutes), arrhythmia non-inducibility (RR: 0.73; 95% CI: 0.33–1.58), acute ablation success (RR: 1.06; 95% CI: 0.65–1.71), or procedural complications (RR: 0.72; 95% CI: 0.28–1.85). However, sedation was associated with significantly lower intraprocedural hemodynamic instability (RR: 0.28; 95% CI: 0.12–0.70). These findings indicate that while sedation and GA have comparable outcomes, sedation may be associated with less hemodynamic instability during VA ablation. However, more high-quality studies are needed to confirm these results.