Risk Assessment of Hemodynamically Significant Arrhythmias after Elective Cardiac Operations with Cardiopulmonary Bypass Using the Modified Nomogram (Retrospective Study)

Aim of the study was to evaluate the feasibility of using a modified nomogram (the M nomogram) to predict the occurrence of new postoperative hemodynamically significant arrhythmias after elective cardiac surgery with cardiopulmonary bypass within 30 days post operation.Materials and methods. This was a retrospective cohort study. The prognostic value of the model using ROC-analysis of the modified nomogram was estimated based on the medical records of 144 patients who underwent elective cardiac surgery with cardiopulmonary bypass.Results. The incidence of new postoperative hemodynamically significant arrhythmias was 13.9% (20 of 144 patients). For the modified nomogram, the AUC was 0.777 [95% CI: 0.661–0.892] (P<0.001); at a cutoff of 12 points, the sensitivity was 60.0% and specificity was 89.52%. The odds ratio was 10.26 (95% CI: 3.63–29.06) (P<0.001). Conclusion. The modified nomogram has an acceptable prognostic value for the occurrence of new hemodynamically significant arrhythmias after elective cardiac operations with cardiopulmonary bypass based on AUC 0.777 [0.661–0.892] (P<0.001), and is currently the best model for predicting the outcome.

Nomogram Models to Predict Postoperative Hyperlactatemia in Patients Undergoing Elective Cardiac Surgery

Objectives: Postoperative hyperlactatemia (POHL) is common in patients undergoing cardiac surgery and is associated with poor outcomes. The purpose of this study was to develop and validate two predictive models for POHL in patients undergoing elective cardiac surgery (ECS).Methods: We conducted a multicenter retrospective study enrolling 13,454 adult patients who underwent ECS. All patients involved in the analysis were randomly assigned to a training set and a validation set. Univariate and multivariate analyses were performed to identify risk factors for POHL in the training cohort. Based on these independent predictors, the nomograms were constructed to predict the probability of POHL and were validated in the validation cohort.Results: A total of 1,430 patients (10.6%) developed POHL after ECS. Age, preoperative left ventricular ejection fraction, renal insufficiency, cardiac surgery history, intraoperative red blood cell transfusion, and cardiopulmonary bypass time were independent predictors and were used to construct a full nomogram. The second nomogram was constructed comprising only the preoperative factors. Both models showed good predictive ability, calibration, and clinical utility. According to the predicted probabilities, four risk groups were defined as very low risk (&lt;0.05), low risk (0.05–0.1), medium risk (0.1–0.3), and high risk groups (&gt;0.3), corresponding to scores of ≤ 180 points, 181–202 points, 203–239 points, and &gt;239 points on the full nomogram, respectively.Conclusions: We developed and validated two nomogram models to predict POHL in patients undergoing ECS. The nomograms may have clinical utility in risk estimation, risk stratification, and targeted interventions.

Clinical Outcomes and Cost of Ventilator Weaning and Endotracheal Extubation Guided by An Established Ventilator Weaning Protocol in Patients Undergoing Elective Cardiac Surgery

Objective: To compare successful early extubation rates, complications, and cost before and after the use of anestablished ventilator weaning protocol in patients undergoing elective cardiac surgery.Materials and Methods: Subjects were adult patients undergoing elective cardiac surgery who were clinically stablewithin 2 hours after surgery. The control group underwent conventional ventilator weaning at the discretion of theirattending staff. The intervention group underwent protocol-guided ventilator weaning. The primary outcome wasa successful early extubation (within 6 hours after surgery). Secondary outcomes were complications from weaningto 24 hours after surgery, and the relevant cost related to respiratory and cardiovascular care within 24 hours afteradmission to the postoperative intensive care unit.Results: The primary outcome occurred in 37 out of 65 patients (56.9%) in the intervention group and in 5 out of65 patients (7.7%) in the control group (adjusted odds ratio 20.6; 95% confidence interval 6.7–62.9, p<0.001). Thecomplication rates were not statistically different between the intervention and control groups (26.2% vs. 20.0%,p=0.41). The relevant cost, approximated by the service charges, related to respiratory and cardiovascular care wassignificantly less in the intervention group than in the control group (median 2,491 vs. 2,711 Thai baht, p<0.001).Conclusion: The use of the established ventilator weaning protocol after elective cardiac surgery was associated witha higher rate of successful early extubation and lower cost related to respiratory and cardiovascular care comparedto the conventional practices of ventilator weaning and extubation. The rates of overall complications were notsignificantly different.

ΔPCO2 and ΔPCO2/C(a−cv)O2 Are Not Predictive of Organ Dysfunction After Cardiopulmonary Bypass

Background: Cardiac surgery is associated with a substantial risk of major adverse events. Although carbon dioxide (CO2)-derived variables such as venous-to-arterial CO2 difference (ΔPCO2), and PCO2 gap to arterial–venous O2 content difference ratio (ΔPCO2/C(a−cv)O2) have been successfully used to predict the prognosis of non-cardiac surgery, their prognostic value after cardiopulmonary bypass (CPB) remains controversial. This hospital-based study explored the relationship between ΔPCO2, ΔPCO2/C(a−cv)O2 and organ dysfunction after CPB.Methods: We prospectively enrolled 114 intensive care unit patients after elective cardiac surgery with CPB. Patients were divided into the organ dysfunction group (OI) and non-organ dysfunction group (n-OI) depending on whether organ dysfunction occurred or not at 48 h after CPB. ΔPCO2 was defined as the difference between central venous and arterial CO2 partial pressure.Results: The OI group has 37 (32.5%) patients, 27 of which (23.7%) had one organ dysfunction and 10 (8.8%) had two or more organ dysfunctions. No statistical significance was found (P = 0.84) for ΔPCO2 in the n-OI group at intensive care unit (ICU) admission (9.0, 7.0–11.0 mmHg), and at 4 (9.0, 7.0–11.0 mmHg), 8 (9.0, 7.0–11.0 mmHg), and 12 h post admission (9.0, 7.0–11.0 mmHg). In the OI group, ΔPCO2 also showed the same trend [ICU admission (9.0, 8.0–12.8 mmHg) and 4 (10.0, 7.0–11.0 mmHg), 8 (10.0, 8.5–12.5 mmHg), and 12 h post admission (9.0, 7.3–11.0 mmHg), P = 0.37]. No statistical difference was found for ΔPCO2/C(a−cv)O2 in the n-OI group (P = 0.46) and OI group (P = 0.39). No difference was detected in ΔPCO2, ΔPCO2/C(a−cv)O2 between groups during the first 12 h after admission (P &gt; 0.05). Subgroup analysis of the patients with two or more failing organs compared to the n-OI group showed that the predictive performance of lactate and Base excess (BE) improved, but not of ΔPCO2 and ΔPCO2/C(a−cv)O2. Regression analysis showed that the BE at 8 h after admission (odds ratio = 1.37, 95%CI: 1.08–1.74, P = 0.009) was a risk factor for organ dysfunction 48 h after CBP.Conclusion : ΔPCO2 and ΔPCO2/C(a−cv)O2 cannot be used as reliable indicators to predict the occurrence of organ dysfunction at 48 h after CBP due to the pathophysiological process that occurs after CBP.

Abstract 14264: National Comparison of Hospital Market Share for Out-of-Hospital Cardiac Arrest and Elective Cardiac Surgery

Introduction: Competition in the healthcare market is a theoretical driver of innovation, cost-savings, and improved quality. When patients are treated for certain emergent conditions, such as out-of-hospital cardiac arrest (OHCA), individuals have less choice in their treating hospital. For patients undergoing elective cardiac valve replacement surgery (EVRS), hospital choice may reflect distinct referral patterns and preferences. Our objective was to compare hospital market share for different cardiac services, thus allowing for better understanding of the care landscape and target interventions to improve outcomes. Methods: Using age-eligible Medicare fee-for-service institutional claims, an emergency department (ED) treated OHCA cohort was identified via ICD-9/10 diagnosis codes and ED charges. EVRS, an inpatient referral procedure, were identified from in-patient summary claims using procedure codes. Market shares were built for each hospital by sequential addition of ZIP-code areas and calculating the hospital’s cumulative market share. Geographic market share areas were defined for each hospital at 90%, 25% and 10% cut-offs if present. Correlation between corresponding market shares and patient counts were assessed using Pearson’s r. Results: Between 1/2013 and 12/2015, we identified 206,162 EVRS claims and 222,018 OHCA claims. Median age was similar (77 vs 78 yrs), as was percent of female patient (43% vs 44%). Very few beneficiaries (0.38%) appeared in both cohorts. Many more hospitals cared for OHCA than EVRS (4482 vs 1170). More OHCA treating hospitals achieved a 25% market share (68% vs 57%) however, EVRS hospital with a 25% market share covered more population (420,294 vs 66,394) and had a greater client radius (21 vs 15 miles). Among the hospitals providing care to both cohorts, the cumulative market share and patient counts were positively correlated (r = 0.49 and 0.46 respectively, p<0.001 for both). Conclusion: Despite many more hospitals providing care for OHCA, the market share for EVRS and OHCA trend together. This market trend, combined with the association of better outcomes with higher OHCA volume suggests that OHCA should be regionalized within markets to facilities that provide elective cardiac surgical procedures.

Effect of ventilation strategy during cardiopulmonary bypass on postoperative pulmonary complications after cardiac surgery: a randomized clinical trial

Background To determine whether maintaining ventilation during cardiopulmonary bypass (CPB) with a different fraction of inspired oxygen (FiO2) had an impact on the occurrence of postoperative pulmonary complications (PPCs). Methods A total of 413 adult patients undergoing elective cardiac surgery with CPB were randomly assigned into three groups: 138 in the NoV group (received no mechanical ventilation during CPB), 138 in the LOV group (received a tidal volume (VT) of 3–4 ml/kg of ideal body weight with the respiratory rate of 10–12 bpm, and the positive end-expiratory pressure of 5–8 cmH2O during CPB; the FiO2 was 30%), and 137 in the HOV group (received the same ventilation parameters settings as the LOV group while the FiO2 was 80%). Results The primary outcomes were the incidence and severity of PPCs during hospitalization. The composite incidence of PPCs did not significantly differ between the NoV (63%), LOV (49%) and HOV (57%) groups (P = 0.069). And there was also no difference regarding the incidence of PPCs between the non-ventilation (NoV) and ventilation (the combination of LOV and HOV) groups. The LOV group was observed a lower proportion of moderate and severe pulmonary complications (grade ≥ 3) than the NoV group (23.1% vs. 44.2%, P = 0.001). Conclusion Maintaining ventilation during CPB did not reduce the incidence of PPCs in patients undergoing cardiac surgery. Trial registration: Chinese Clinical Trial Registry ChiCTR1800015261. Prospectively registered 19 March 2018. http://www.chictr.org.cn/showproj.aspx?proj=25982

Comparison of the resonance sonorheometry based Quantra® system with rotational thromboelastometry ROTEM® sigma in cardiac surgery – a prospective observational study

Background Measures of the sonorheometry based Quantra® viscoelastic hemostatic analyzer (HemoSonics, LCC, Charlottesville, VA, USA) were compared with corresponding results of the ROTEM® sigma device (Instrumentation Laboratory, Bedford, MA, USA). Methods In thirty-eight patients scheduled for elective cardiac surgery between December 2018 and October 2019, blood samples were taken after induction of anesthesia (sample 1) and after heparin neutralization (sample 2) and measured on Quantra (QPlus® Cartridge) and ROTEM sigma (ROTEM® sigma complete + hep Cartridge). Clot times and clot stiffness values were recorded. Clot stiffness values of ROTEM amplitudes (A in mm) were converted to shear modulus (G) in hectoPascal (hPa): G (hPa) = (5 x A)/(100-A). Additionally, time-to-results was recorded. Spearman rank test correlation and Bland Altman analysis were performed. Results Clot stiffness parameters of the Quantra correlated strongly with corresponding measurements of the ROTEM with r = 0.93 and 0.94 for EXTEM A10 vs CS and r = 0.94 and 0.96 for FIBTEM A10 vs FCS for sample 1 and 2, respectively. Quantra clot time correlated strongly with ROTEM INTEM CT with r = 0.71 for sample 1 and r = 0.75 for sample 2. However, Bland Altman analysis showed no agreement in all compared assays of both methods. The median time to delivery of first and complete results was significantly shorter for Quantra (412 and 658 s) compared to ROTEM sigma (839 and 1290 s). Conclusions The Quantra showed a strong correlation with the ROTEM sigma for determining clot times and clot stiffness and the parameters assess similar aspects of clot development. However, these parameters are not directly interchangeable and implicate that separate cut-off values need to be established for users of the Quantra device. Word count: 278. Trial registration The study was retrospectively registered with ClinicalTrials.gov (ID: NCT04210830) at December 20th 2019.

Development and Validation of Nomogram Models for Postoperative Pneumonia in Adult Patients Undergoing Elective Cardiac Surgery

Background: Postoperative pneumonia (POP) is a frequent complication following cardiac surgery, related to increased morbidity, mortality and healthcare costs. The objectives of this study were to investigate the risk factors associated with POP in adults undergoing elective cardiac surgery and to develop and validate nomogram models.Methods: We conducted a multicenter retrospective study in four cardiac centers in China. Adults operated with elective open-heart surgery from 2016 to 2020 were included. Patients were randomly allocated to training and validation sets by 7:3 ratio. Demographics, comorbidities, laboratory data, surgical factors, and postoperative outcomes were collected and analyzed. Risk factors for POP were identified by univariate and multivariate analysis. Nomograms were constructed based on the multivariate logistic regression models and were evaluated with calibration, discrimination and decision curve analysis.Results: A total of 13,380 patients meeting the criteria were included and POP developed in 882 patients (6.6%). The mortality was 2.0%, but it increased significantly in patients with POP (25.1 vs. 0.4%, P &lt; 0.001). Using preoperative and intraoperative variables, we constructed a full nomogram model based on ten independent risk factors and a preoperative nomogram model based on eight preoperative factors. Both nomograms demonstrated good calibration, discrimination, and were well validated. The decision curves indicated significant clinical usefulness. Finally, four risk intervals were defined for better clinical application.Conclusions: We developed and validated two nomogram models for POP following elective cardiac surgery using preoperative and intraoperative factors, which may be helpful for individualized risk evaluation and prevention decisions.