Sources of Variation in Hospital-Level Infection Rates After Coronary Artery Bypass Grafting: An Analysis of The Society of Thoracic Surgeons Adult Heart Surgery Database

Outcomes of nonemergency cardiac surgery after overnight operative workload: A statewide experience

Objective

Cardiac surgeons experience unpredictable overnight operative responsibilities, with variable rest before same-day, first-start scheduled cases. This study evaluated the frequency and associated impact of a surgeon's overnight operative workload on the outcomes of their same-day, first-start operations.

Methods

A statewide cardiac surgery quality database was queried for adult cardiac surgical operations between July 1, 2011, and March 1, 2021. Nonemergency, first-start, Society of Thoracic Surgeons predicted risk of mortality operations were stratified by whether or not the surgeon performed an overnight operation that ended after midnight. A generalized mixed effect model was used to evaluate the effect of overnight operations on a Society of Thoracic Surgeons composite outcome (5 major morbidities or operative mortality) of the first-start operation.

Results

Of all first-start operations, 0.4% (239/56,272) had a preceding operation ending after midnight. The Society of Thoracic Surgeons predicted risk of morbidity and mortality was similar for first-start operations whether preceded by an overnight operation or not (overnight operation: 11.3%; no overnight operation: 11.7%, P = .42). Unadjusted rates of the primary outcome were not significantly different after an overnight operation (overnight operation: 13.4%; no overnight operation: 12.3%, P = .59). After adjustment, overnight operations did not significantly impact the risk of major morbidity or mortality for first-start operations (adjusted odds ratio, 1.1, P = .70).

Conclusions

First-start cardiac operations performed after an overnight operation represent a small subset of all first-start Society of Thoracic Surgeons predicted risk operations. Overnight operations do not significantly influence the risk of major morbidity or mortality of first-start operations, which suggests that surgeons exercise proper judgment in determining appropriate workloads.

Impact of Pulmonary Complications on Outcomes and Resource Use After Elective Cardiac Surgery

OBJECTIVE

To characterize the impact of pulmonary complications (PCs) on mortality, costs, and readmissions after elective cardiac operations in a national cohort and to test for hospital-level variation in PC.

BACKGROUND

PC after cardiac surgery are targets for quality improvement efforts. Contemporary studies evaluating the impact of PC on outcomes are lacking, as is data regarding hospital-level variation in the incidence of PC.

METHODS

Adults undergoing elective coronary artery bypass grafting and/or valve operations were identified in the 2016-2019 Nationwide Readmissions Database. PC was defined as a composite of reintubation, prolonged (>24 hours) ventilation, tracheostomy, or pneumonia. Generalized linear models were fit to evaluate associations between PC and outcomes. Institutional variation in PC was studied using observed-to-expected ratios.

RESULTS

Of 588,480 patients meeting study criteria, 6.7% developed PC. After risk adjustment, PC was associated with increased odds of mortality (14.6, 95% CI, 12.6-14.8), as well as a 7.9-day (95% CI, 7.6-8.2) increase in length of stay and $41,300 (95% CI, 39,600-42,900) in attributable costs. PC was associated with 1.3-fold greater hazard of readmission and greater incident mortality at readmission (6.7% vs 1.9%, P <0.001). Significant hospital-level variation in PC was present, with observed-to-expected ratios ranging from 0.1 to 7.7.

CONCLUSIONS

Pulmonary complications remain common after cardiac surgery and are associated with substantially increased mortality and expenditures. Significant hospital-level variation in PC exists in the United States, suggesting the need for systematic quality improvement efforts to reduce PC and their impact on outcomes.

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.

Digital Holographic Microscopy for Label-Free Detection of Leukocyte Alternations Associated with Perioperative Inflammation after Cardiac Surgery

In a prospective observational pilot study on patients undergoing elective cardiac surgery with cardiopulmonary bypass, we evaluated label-free quantitative phase imaging (QPI) with digital holographic microscopy (DHM) to describe perioperative inflammation by changes in biophysical cell properties of lymphocytes and monocytes. Blood samples from 25 patients were investigated prior to cardiac surgery and postoperatively at day 1, 3 and 6. Biophysical and morphological cell parameters accessible with DHM, such as cell volume, refractive index, dry mass, and cell shape related form factor, were acquired and compared to common flow cytometric blood cell markers of inflammation and selected routine laboratory parameters. In all examined patients, cardiac surgery induced an acute inflammatory response as indicated by changes in routine laboratory parameters and flow cytometric cell markers. DHM results were associated with routine laboratory and flow cytometric data and correlated with complications in the postoperative course. In a subgroup analysis, patients were classified according to the inflammation related C-reactive protein (CRP) level, treatment with epinephrine and the occurrence of postoperative complications. Patients with regular courses, without epinephrine treatment and with low CRP values showed a postoperative lymphocyte volume increase. In contrast, the group of patients with increased CRP levels indicated an even further enlarged lymphocyte volume, while for the groups of epinephrine treated patients and patients with complicative courses, no postoperative lymphocyte volume changes were detected. In summary, the study demonstrates the capability of DHM to describe biophysical cell parameters of perioperative lymphocytes and monocytes changes in cardiac surgery patients. The pattern of correlations between biophysical DHM data and laboratory parameters, flow cytometric cell markers, and the postoperative course exemplify DHM as a promising diagnostic tool for a characterization of inflammatory processes and course of disease.

Impact of preoperative nasopharyngeal cultures on surgical site infection after open heart surgery

Objectives

Despite advances in surgical techniques and management, surgical site infection (SSI) is still important after cardiovascular surgery. We investigated to determine whether or not preoperative nasopharyngeal cultures (NCx) can predict SSI and its microbial spectrum.

Methods

A retrospective review was done in 1226 consecutive patients undergoing NCx and cardiac and thoracic aortic surgery via median sternotomy who were cared for with the standard SSI bundle between 2013 and 2018. Microorganisms isolated from the NCx and SSI pathogens were counted to explore the microbial pattern and associated variables in patients with and without postoperative SSI. Perioperative management was not changed by collection of preoperative NCx.

Results

There were 1281 and 127 microorganisms, including coagulase-negative Staphylococcus as the most prevalent, isolated from 784 nasal and 111 pharyngeal specimens, respectively. Postoperative SSI occurred in 31 patients (2.47%), including chest, groin, and leg SSI. Significant coincidence of the SSI pathogens with the NCx microorganisms was not observed. However, the patients with SSI showed significantly higher positive rates of preoperative NCx than those without SSI. The sensitivity/specificity of NCx for SSI were 81%/37% for nasal and 45%/92% for pharyngeal, respectively. The negative predictive value of NCx for ruling out SSI was 98.6% for nasal and 98.4% for pharyngeal, respectively. Independent risk factors for postoperative SSI included female sex, diabetes mellitus, positive preoperative NCx, and postoperative use of Portex Mini-Trach (Smiths Medical, Minneapolis, Minn) or tracheostomy on multivariate analysis.

Conclusions

Preoperative NCx may be useful to predict SSI after open heart surgery via median sternotomy, as well as screening for methicillin-resistant Staphylococcus aureus.

Prognostic value of SARS-CoV-2 on patients undergoing cardiac surgery

Objective

To analyze Italian Cardiac Surgery experience during the pandemic of severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) identifying risk factors for overall mortality according to coronavirus disease 2019 (COVID‐19) status.

Methods

From February 20 to May 31, 2020, 1354 consecutive adult patients underwent cardiac surgery at 22 Italian Centers; 589 (43.5%), patients came from the red zone. Based on COVID‐19 status, 1306 (96.5%) were negative to SARS‐CoV‐2 (COVID‐N), and 48 (3.5%) were positive to SARS‐CoV‐2 (COVID‐P); among the COVID‐P 11 (22.9%) and 37 (77.1%) become positive, before and after surgery, respectively. Surgical procedures were as follows: 396 (29.2%) isolated coronary artery bypass grafting (CABG), 714 (52.7%) isolated non‐CABG procedures, 207 (15.3%) two associate procedures, and three or more procedures in 37 (2.7%). Heart failure was significantly predominant in group COVID‐N (10.4% vs. 2.5%, p = .01).

Results

Overall in‐hospital mortality was 1.6% (22 cases), being significantly higher in COVID‐P group (10 cases, 20.8% vs. 12, 0.9%, p < .001). Multivariable analysis identified COVID‐P condition as a predictor of in‐hospital mortality together with emergency status. In the COVID‐P subgroup, the multivariable analysis identified increasing age and low oxygen saturation at admission as risk factors for in‐hospital mortality.

Conclusion

As expected, SARS‐CoV‐2 infection, either before or soon after cardiac surgery significantly increases in‐hospital mortality. Moreover, among COVID‐19‐positive patients, older age and poor oxygenation upon admission seem to be associated with worse outcomes.

Plasma and Lung Tissue Pharmacokinetics of Ceftaroline Fosamil in Patients Undergoing Cardiac Surgery with Cardiopulmonary Bypass: an In Vivo Microdialysis Study

Ceftaroline fosamil, a fifth-generation cephalosporin antibiotic with activity against methicillin-resistant Staphylococcus aureus (MRSA), is currently approved for the treatment of pneumonia and complicated skin and soft tissue infections. However, pharmacokinetics data on free lung tissue concentrations in critical patient populations are lacking. The aim of this study was to evaluate the pharmacokinetics of the high-dose regimen of ceftaroline in plasma and lung tissue in cardiac surgery patients during intermittent and continuous administration. Nine patients undergoing elective cardiac surgery on cardiopulmonary bypass were included in this study and randomly assigned to intermittent or continuous administration. Eighteen hundred milligrams of ceftaroline fosamil was administered intravenously as either 600 mg over 2 h every 8 h (q8h) (intermittent group) or 600 mg over 2 h (loading dose) plus 1,200 mg over 22 h (continuous group). Interstitial lung tissue concentrations were measured by in vivo microdialysis. Relevant pharmacokinetics parameters were calculated for each group. Plasma exposure levels during intermittent and continuous administration were comparable to those of previously published studies and did not differ significantly between the two groups. In vivo microdialysis demonstrated reliable and adequate penetration of ceftaroline into lung tissue during intermittent and continuous administration. The steady-state area under the concentration-time curve from 0 to 8 h (AUCss 0-8) and the ratio of AUCSS 0-8 in lung tissue and AUC in plasma (AUClung/plasma) were descriptively higher in the continuous group. Continuous administration of ceftaroline fosamil achieved a significantly higher proportion of time for which the free drug concentration remained above 4 times the minimal inhibitory concentration (MIC) during the dosing interval (% fT>4xMIC) than intermittent administration for pathogens with a MIC of 1 mg/liter. Ceftaroline showed adequate penetration into interstitial lung tissue of critically ill patients undergoing major cardiothoracic surgery, supporting its use for pneumonia caused by susceptible pathogens.

The Economic Implications of Introducing Single-Patient ECG Systems for Cardiac Surgery in Australia

Introduction

Sternal wound infections (SWIs) are severe adverse events of cardiac surgery. This study aimed to estimate the economic burden of SWIs following coronary artery bypass grafts (CABG) in Australia. It also aimed to estimate the national and hospital cost-benefit of adopting single-patient electrocardiograph (spECG) systems for CABG monitoring, a measure that reduces the rate of surgical site infections (SSIs).

Material and Methods

A literature review, which focused on CABG-related SSIs, was conducted to identify data which were then used to adapt a published Markov cost-effectiveness model. The model adopted an Australian hospital perspective.

Results

The average SWI-related cost of care increase per patient was estimated at 1022 Australian dollars (AUD), and the annual burden to the Australian health care system at AUD 9.2 million. SWI burden comprised 360 additional intensive care unit (ICU) days; 1979 additional general ward (GW) days; and 186 readmissions. Implementing spECG resulted in 103 fewer ICU days, 565 fewer GW days, 48 avoided readmissions, and a total national cost saving of AUD 2.5 million, annually. A hospital performing 200 yearly CABGs was estimated to save AUD 54,830.

Conclusion

SWIs cause substantial costs to the Australian health care system. Implementing new technologies shown to reduce the SWI rate is likely to benefit patients and reduce costs.

Interhospital variability in health care-associated infections and payments after durable ventricular assist device implant among Medicare beneficiaries

OBJECTIVE

The objective of this study was to investigate variations across hospitals in infection rates and associated costs, the latter reflected in 90-day Medicare payments. Despite high rates and expenditures of health care--associated infections associated with durable ventricular assist device implantation, few studies have examined interhospital variation and associated costs.

METHODS

Clinical data on 8688 patients who received primary durable ventricular assist devices from July 2008 to July 2017 from the Society of Thoracic Surgeons Interagency Registry for Mechanically Assisted Circulatory Support (Intermacs) hospitals (n = 120) were merged with postimplantation 90-day Medicare claims. Terciles of hospital-specific, risk-adjusted infection rates per 100 patient-months were estimated using Intermacs and associated with Medicare payments (among 5440 Medicare beneficiaries). Primary outcomes included infections within 90 days of implantation and Medicare payments.

RESULTS

There were 3982 infections identified among 27.8% (2417/8688) of patients developing an infection. The median (25th, 75th percentile) adjusted incidence of infections (per 100 patient-months) across hospitals was 14.3 (9.3, 19.5) and varied according to hospital (range, 0.0-35.6). Total Medicare payments from implantation to 90 days were 9.0% (absolute difference: $13,652) greater in high versus low infection tercile hospitals (P < .0001). The period between implantation to discharge accounted for 73.1% of the difference in payments during the implantation to 90-day period across terciles.

CONCLUSIONS

Health care--associated infection rates post durable ventricular assist device implantation varied according to hospital and were associated with increased 90-day Medicare expenditures. Interventions targeting preventing infections could improve the value of durable ventricular assist device support from the societal and hospital perspectives.

Impact of Postoperative Infections on Readmission and Resource Use in Elective Cardiac Surgery

BACKGROUND

Efforts to reduce postoperative infections have garnered national attention, leading to practice guidelines for cardiac surgical perioperative care. The present study characterized the impact of healthcare-acquired infection (HAI) on index hospitalization costs and post-discharge healthcare utilization.

METHODS

Adults undergoing elective coronary artery bypass grafting (CABG) and/or valve operations were identified in the 2016-2018 Nationwide Readmissions Database. Infections were categorized into bloodstream, gastrointestinal, pulmonary, surgical site, or urinary tract infections. Generalized linear or flexible hazard models were used to assess associations between infections and outcomes. Observed-to-expected (O/E) ratios were generated to examine inter-hospital variation in HAI.

RESULTS

Of an estimated 444,165 patients, 8.0% developed HAI. Patients with HAI were older, had a greater burden of chronic diseases, and more commonly underwent CABG/valve or multi-valve operations (all p<0.001). HAI was independently associated with mortality (odds ratio 4.02, 95% CI 3.67-4.40), non-home discharge (3.48, 95% CI 3.21-3.78), and a cost increase of $23,000 (95% CI 20,900-25,200). At 90 days, HAI was associated with greater hazard of readmission (1.29, 95% CI 1.24-1.35). Pulmonary infections had the greatest incremental impact on patient-level ($24,500, 95% CI 23,100-26,00) and annual cohort costs ($121.8 million, 95% CI 102.2-142.9 million). Significant hospital level variation in HAI was evident, with O/E ranging from 0.17 to 4.3 for cases performed in 2018.

CONCLUSIONS

Infections following cardiac surgery remain common and are associated with inferior outcomes and increased resource use. The presence of inter-hospital variation in this contemporary cohort emphasizes the ongoing need for systematic approaches in their prevention and management.

Novel Assessments of Technical and Nontechnical Cardiac Surgery Quality: Protocol for a Mixed Methods Study

BACKGROUND

Of the 150,000 patients annually undergoing coronary artery bypass grafting, 35% develop complications that increase mortality 5 fold and expenditure by 50%. Differences in patient risk and operative approach explain only 2% of hospital variations in some complications. The intraoperative phase remains understudied as a source of variation, despite its complexity and amenability to improvement.

OBJECTIVE

The objectives of this study are to (1) investigate the relationship between peer assessments of intraoperative technical skills and nontechnical practices with risk-adjusted complication rates and (2) evaluate the feasibility of using computer-based metrics to automate the assessment of important intraoperative technical skills and nontechnical practices.

METHODS

This multicenter study will use video recording, established peer assessment tools, electronic health record data, registry data, and a high-dimensional computer vision approach to (1) investigate the relationship between peer assessments of surgeon technical skills and variability in risk-adjusted patient adverse events; (2) investigate the relationship between peer assessments of intraoperative team-based nontechnical practices and variability in risk-adjusted patient adverse events; and (3) use quantitative and qualitative methods to explore the feasibility of using objective, data-driven, computer-based assessments to automate the measurement of important intraoperative determinants of risk-adjusted patient adverse events.

RESULTS

The project has been funded by the National Heart, Lung and Blood Institute in 2019 (R01HL146619). Preliminary Institutional Review Board review has been completed at the University of Michigan by the Institutional Review Boards of the University of Michigan Medical School.

CONCLUSIONS

We anticipate that this project will substantially increase our ability to assess determinants of variation in complication rates by specifically studying a surgeon's technical skills and operating room team member nontechnical practices. These findings may provide effective targets for future trials or quality improvement initiatives to enhance the quality and safety of cardiac surgical patient care.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

PRR1-10.2196/22536.

Determinants of Value in Coronary Artery Bypass Grafting

Background Over 180 000 coronary artery bypass grafting (CABG) procedures are performed annually, accounting for $7 to $10 billion in episode expenditures. Assessing tradeoffs between spending and quality contributing to value during 90-day episodes has not been conducted but is essential for success in bundled reimbursement models. We, therefore, identified determinants of variability in hospital 90-day episode value for CABG. Methods Medicare and private payor admissions for isolated CABG from 2014 to 2016 were retrospectively linked to clinical registry data for 33 nonfederal hospitals in Michigan. Hospital composite risk-adjusted complication rates (≥1 National Quality Forum-endorsed, Society of Thoracic Surgeons measure: deep sternal wound infection, renal failure, prolonged ventilation >24 hours, stroke, re-exploration, and operative mortality) and 90-day risk-adjusted, price-standardized episode payments were used to categorize hospitals by value by defining the intersection between complications and spending. Results Among 2573 total patients, those at low- versus high-value hospitals had a higher percentage of prolonged length of stay >14 days (9.3% versus 2.4%, P=0.006), prolonged ventilation (17.6% versus 4.8%, P<0.001), and operative mortality (4.8% versus 0.6%, P=0.001). Mean total episode payments were $51 509 at low-compared with $45 526 at high-value hospitals (P<0.001), driven by higher readmission ($3675 versus $2177, P=0.005), professional ($7462 versus $6090, P<0.001), postacute care ($7315 versus $5947, P=0.031), and index hospitalization payments ($33 474 versus $30 800, P<0.001). Among patients not experiencing a complication or 30-day readmission (1923/2573, 74.7%), low-value hospitals had higher inpatient evaluation and management payments ($1405 versus $752, P<0.001) and higher utilization of inpatient rehabilitation (7% versus 2%, P<0.001), but lower utilization of home health (66% versus 73%, P=0.016) and emergency department services (13% versus 17%, P=0.034). Conclusions To succeed in emerging bundled reimbursement programs for CABG, hospitals and physicians should identify strategies to minimize complications while optimizing inpatient evaluation and management spending and use of inpatient rehabilitation, home health, and emergency department services.

Evaluating the Impact of Pneumonia Prevention Recommendations After Cardiac Surgery

BACKGROUND

Pneumonia is the most prevalent healthcare-associated infection after coronary artery bypass grafting (CABG), but the relative effectiveness of strategies to reduce its incidence remains unclear. We evaluated the relationship between healthcare-associated infection recommendations and risk of pneumonia after CABG.

METHODS

Pneumonia prevention practice recommendations were developed based on literature review and analysis of semistructured interviews with key health care personnel across centers with low (<5.9%), medium (5.9%-6.1%), and high (>6.1%) rates of pneumonia. These practices were implemented among 2482 patients undergoing CABG from 2016 to 2017 across 18 centers. The independent effect of each practice in reducing pneumonia was assessed using multivariable logistic regression, adjusting for baseline risk and center. A composite (bundle) score was calculated as the number of practices (0 to 4) each patient received.

RESULTS

Recommended pneumonia prevention practices included lung protective ventilation management, early extubation, progressive ambulation, and avoidance of postoperative bronchodilator therapy. Pneumonia occurred in 2.4% of patients. Lung protective ventilation (adjusted odds ratio [ORadj], 0.45; 95% confidence interval [CI], 0.22-0.92), ambulation (ORadj, 0.08; 95% CI, 0.04-0.17), and postoperative ventilation of less than 6 hours (ORadj, 0.47; 95% CI, 0.26-0.87) were significantly associated with lower odds of pneumonia. Postoperative bronchodilator therapy (ORadj, 4.83; 95% CI, 2.20-10.7) was significantly associated with higher odds. Risk-adjusted rates of pneumonia, operative mortality, and intensive care unit length of stay were lower in patients with higher bundle scores (all P-trend < .01).

CONCLUSIONS

These pneumonia prevention recommendations may serve as effective targets for avoiding postoperative healthcare-associated infections.

Hospital Variability Drives Inconsistency in Antiplatelet Use After Coronary Bypass

BACKGROUND

Continuation of dual antiplatelet therapy (DAPT) after coronary artery bypass grafting (CABG) after acute myocardial infarction is recommended by current guidelines. We sought to evaluate guideline adherence over time and factors associated with postoperative DAPT within a regional consortium.

METHODS

Isolated CABG patients from 2011 to 2017 who had a myocardial infarction within 21 days prior to surgery were included. Patients were stratified by DAPT prescription at discharge and by time period, early (2011-2014) vs late (2015-2017). Hierarchical regressions were then performed to evaluate factors influencing DAPT use after CABG.

RESULTS

A total of 7314 patients were included with an overall rate of DAPT utilization of 31.2% that increased from 29.6% in the early to 33.4% in the late era (P < .01). There was considerable variability in hospital rates of DAPT (range 9.5%-92.1%) and hospital level changes over time (26% increased, 11% decreased, and 63% remained stable). After adjustment for clinical factors, era was not associated with DAPT use but treating hospital remained significantly associated with DAPT use. Other clinical factors associated with increased DAPT utilization included off-pump surgery (odds ratio [OR] 4.48, P < .01) and prior percutaneous coronary intervention (OR 2.02, P < .01), and atrial fibrillation (OR 0.39, P < .01) was associated with decreased utilization.

CONCLUSIONS

Dual antiplatelet use has increased between 2011 and 2017, driven primarily by evolving patient demographics. Significant hospital-level variability drives inconsistency in DAPT utilization. Efforts to promote DAPT use for patients treated with CABG after myocardial infarction in concordance with current guidelines should be targeted at the hospital level.

Stage 1 acute kidney injury is independently associated with infection following cardiac surgery

OBJECTIVES

Severe acute kidney injury (AKI) is a known risk factor for infection and mortality. However, whether stage 1 AKI is a risk factor for infection has not been evaluated in adults. We hypothesized that stage 1 AKI following cardiac surgery would independently associate with infection and mortality.

METHODS

In this retrospective propensity score-matched study, we evaluated 1620 adult patients who underwent nonemergent cardiac surgery at the University of Colorado Hospital from 2011 to 2017. Patients who developed stage 1 AKI by Kidney Disease Improving Global Outcomes creatinine criteria within 72 hours of surgery were matched to patients who did not develop AKI. The primary outcome was an infection, defined as a new surgical-site infection, positive blood or urine culture, or development of pneumonia. Secondary outcomes included in-hospital mortality, stroke, and intensive care unit (ICU) and hospital length of stay (LOS).

RESULTS

Stage 1 AKI occurred in 293 patients (18.3%). Infection occurred in 20.9% of patients with stage 1 AKI compared with 8.1% in the no-AKI group (P < .001). In propensity-score matched analysis, stage 1 AKI independently associated with increased infection (odds ratio [OR]; 2.24, 95% confidence interval [CI], 1.37-3.17), ICU LOS (OR, 2.38; 95% CI, 1.71-3.31), and hospital LOS (OR, 1.30; 95% CI, 1.17-1.45).

CONCLUSIONS

Stage 1 AKI is independently associated with postoperative infection, ICU LOS, and hospital LOS. Treatment strategies focused on prevention, early recognition, and optimal medical management of AKI may decrease significant postoperative morbidity.

Collaborative Quality Improvement Reduces Postoperative Pneumonia After Isolated Coronary Artery Bypass Grafting Surgery

BACKGROUND

To date, studies evaluating outcome improvements associated with participation in physician-led collaboratives have been limited by the absence of a contemporaneous control group. We examined post cardiac surgery pneumonia rates associated with participation in a statewide, quality improvement collaborative relative to a national physician reporting program.

METHODS AND RESULTS

We evaluated 911 754 coronary artery bypass operations (July 1, 2011, to June 30, 2017) performed across 1198 hospitals participating in a voluntary national physician reporting program (Society of Thoracic Surgeons [STS]), including 33 that participated in a Michigan-based collaborative (MI-Collaborative). Unlike STS hospitals not participating in the MI-Collaborative (i.e., STSnonMI) that solely received blinded reports, MI-Collaborative hospitals received a multi-faceted intervention starting November 2012 (quarterly in-person meetings showcasing unblinded data, webinars, site visits). Eighteen of the MI-Collaborative hospitals received additional support to implement recommended pneumonia prevention practices ("MI-CollaborativePlus"), whereas 15 did not ("MI-CollaborativeOnly"). We evaluated rates of postoperative pneumonia, adjusting for patient mix and hospital effects. Baseline patient characteristics were qualitatively similar between groups and time. During the preintervention period (Q3/2011 through Q3/2012), there was no statistically significant difference in the adjusted odds of pneumonia for STS hospitals participating in the MI-Collaborative compared to the STS non-MI hospitals. However, during the intervention period (Q4/2012 through Q2/2017), there was a significant 2% reduction per quarter in the adjusted odds of pneumonia for MI-Collaborative hospitals (n=33) relative to the STS-nonMI hospitals. There was a significant 3% per quarter reduction in the adjusted odds of pneumonia for the MI-CollaborativeOnly (n=15) hospitals relative to the STS-nonMI hospitals. Over the course of the overall study period, the STS-nonMI hospitals had a 1.96% reduction in risk-adjusted pneumonia (pre- vs. intervention periods), which was less than the MI-Collaborative (3.23%, P=0.011). Over the same time period, the MI-CollaborativePlus (n=18) reduced adjusted pneumonia rates by 10.29%, P=0.001.

CONCLUSIONS

Participation in a physician-led collaborative was associated with significant reductions in pneumonia relative to a national quality reporting program. Interventions including collaborative learning may yield superior outcomes relative to solely using physician feedback reporting.

CLINICAL TRIAL REGISTRATION

URL: https://www.clinicaltrials.gov . Unique identifier: NCT02068716.

Association Between Postoperative Pneumonia and 90-Day Episode Payments and Outcomes Among Medicare Beneficiaries Undergoing Cardiac Surgery

Background Postoperative pneumonia is the most common healthcare-associated infection in cardiac surgical patients, yet their impact across a 90-day episode of care remains unknown. Our objective was to examine the relationship between pneumonia and 90-day episode payments and outcomes among Medicare beneficiaries undergoing cardiac surgery. Methods and Results Medicare claims were used to identify beneficiaries with episodes of coronary artery bypass grafting (CABG; n=56 728) and valve surgery (n=56 377) across 1045 centers between April 2014 and March 2015. Using a published diagnosis code-based algorithm, we identified pneumonia in 6.4% CABG episodes and 6.6% of valve surgery episodes. We compared price-standardized 90-day episode payments and outcome measures (postoperative length of stay, discharge to postacute care, mortality, and readmission) between beneficiaries with and without pneumonia using hierarchical regression models, adjusting for patient factors and hospital random effects. Pneumonia was associated with 24.5% higher episode payments for CABG ($46 723 versus $37 496; P<0.001) and 26.5% higher episode payments for valve surgery ($61 544 versus $48 549; P<0.001). For both cohorts, pneumonia was significantly associated with longer postoperative length of stay (CABG: +4.1 days, valve: +5.6 days), more frequent discharge to postacute care (CABG: odds ratio [OR]=1.99, valve: OR=2.17), and higher rates of 30-day mortality (CABG: OR=2.42, valve: OR=2.57) and 90-day readmission (CABG: OR=1.20, valve: OR=1.25), all P<0.001. We compared episode payments and outcomes across terciles of pneumonia rates and found that high pneumonia rate hospitals had higher episode payments and poorer outcomes compared with episodes at low pneumonia rate hospitals in both CABG and valve surgery cohorts. Conclusions Postoperative pneumonia was associated with significantly higher 90-day episode payments and inferior outcomes at the patient and hospital level. Future work should examine whether reducing pneumonia after cardiac surgery reduces episode spending and improves outcomes, which could facilitate hospital success in value-based reimbursement programs.

Infections and outcomes after cardiac surgery-The impact of outbreaks traced to transesophageal echocardiography probes

Background

Infections are a frequent complication of cardiac surgery. The intraoperative use of transesophageal echocardiography (TEE) may be an underrecognized risk factor for post‐operative infections. The aim of this study was to investigate infection rates and outcomes after cardiac surgery in a nationwide cohort, especially in relation to periods where surface damaged TEE probes were used.

Methods

This was a retrospective, observational study at Landspitali University Hospital. All consecutive cardiac surgery patients from 1 January 2013 to 31 December 2017 were included. Patients’ charts were reviewed for evidence of infection, post‐operative complications or death.

Results

During the study period, 973 patients underwent cardiac surgery at Landspitali and 198 (20.3%) developed a post‐operative infection. The most common infections were: Pneumonia (9.1%), superficial surgical site (5.7%), bloodstream (2.8%) and deep sternal wound (1.7%). Risk factors for developing an infection included: The duration of procedure, age, insulin‐dependent diabetes, EuroScore II, reoperation for bleeding and an operation in a period with a surface damaged TEE probe in use. Twenty‐two patients were infected with a multidrug resistant strain of Klebsiella oxytoca, 10 patients with Pseudomonas aeruginosa and two patients developed endocarditis with Enterococcus faecalis. All three pathogens were cultured from the TEE probe in use at respective time, after decontamination. The 30‐day mortality rate in the patient cohort was 3.2%.

Conclusions

The intraoperative use of surface damaged TEE probes caused two serious infection outbreaks in patients after cardiac surgery. TEE probes need careful visual inspection during decontamination and probe sheaths are recommended.

Variation between hospitals in outcomes following cardiac surgery in the UK

INTRODUCTION

We examine the influence of variations in provision of cardiac surgery in the UK at hospital level on patient outcomes and also to assess whether there is an inequality of access and delivery of healthcare. Cardiothoracic surgery has pioneered the reporting of surgeon-specific outcomes, which other specialties have followed. We set out to identify factors other than the individual surgeon, which can affect outcomes and enable other surgical specialties to adopt a similar model.

MATERIALS AND METHODS

A retrospective analysis of prospectively collected data of patient and hospital level factors between 2013 and 2016 from 16 cardiac surgical units in the UK were analysed through the Society for Cardiothoracic Surgery of Great Britain and Ireland and the Royal College of Surgeons Research Collaborative. Patient demographic data, risks factors, postoperative complications and in-hospital mortality, as well as hospital-level factors such as number of beds and operating theatres, were collected. Correlation between outcome measures was assessed using Pearson's correlation coefficient. Associations between hospital-level factors and outcomes were assessed using univariable and multivariable regression models.

RESULTS

Of 50,871 patients (60.5% of UK caseload), 25% were older than 75 years and 29% were female. There was considerable variation between units in patient comorbidities, bed distribution and staffing. All hospitals had dedicated cardiothoracic intensive care beds and consultants. Median survival was 97.9% (range 96.3-98.6%). Postoperative complications included re-sternotomy for bleeding (median 4.8%; range 3.5-6.9%) and mediastinitis (0.4%; 0.1-1.0%), transient ischaemic attack/cerebrovascular accident (1.7%; range 0.3-3.0%), haemofiltration (3.7%; range 0.8-6.8%), intra-aortic balloon pump use (3.3%; range 0.4-7.4%), tracheostomy (1.6%; range 1.3-2.6%) and laparotomy (0.3%; range 0.2-0.6%). There was variation in outcomes between hospitals. Univariable analysis showed a small number of positive associations between hospital-level factors and outcomes but none remained significant in multivariable models.

CONCLUSIONS

Variations among hospital level factors exists in both delivery of, and outcomes, following cardiac surgery in the UK. However, there was no clear association between these factors and patient outcomes. This negative finding could be explained by differences in outcome definition, differences in risk factors between centres that are not captured by standard risk stratification scores or individual surgeon/team performance.

Off-Pump Versus On-Pump Impact: Diabetic Patient 5-Year Coronary Artery Bypass Clinical Outcomes

BACKGROUND

For diabetic patients who require coronary artery bypass graft (CABG) operation, controversy persists whether an off-pump or an on-pump approach may be advantageous. This US-based, multicenter, randomized, controlled trial, Department of Veterans Affairs Randomization On versus Off Bypass Follow-up Study, compared diabetic patients' 5-year clinical outcomes for off-pump versus on-pump procedures.

METHODS

From 2002 to 2008, 835 medically treated (ie, oral hypoglycemic agent or insulin) diabetic patients underwent either off-pump (n = 402) or on-pump (n = 433) CABG. Five-year primary end points included all-cause death and major adverse cardiovascular events (MACE; composite included all-cause death, myocardial infarction, or repeat revascularization). Secondary 5-year end points included cardiac death and MACE-related components. With baseline risk factors balanced, outcomes were evaluated by using a p value less than or equal to 0.01; nonsignificant trends were reported for p values greater than 0.01 and less than or equal to 0.15.

RESULTS

Five-year all-cause death rates were 20.2% off pump versus 14.1% on pump (p = 0.0198). No differences were seen in MACE (32.6% off-pump approach versus 28.6% on-pump approach, p = 0.216), repeat revascularization (12.4% off-pump approach versus 11.8% on-pump approach, p = 0.770), and nonfatal myocardial infarction (12.7% off-pump approach versus 10.4% on-pump approach, p = 0.299). Cardiac death trended worse with off-pump CABG (9.0%) than with on-pump CABG (6.25%, p = 0.137). Sensitivity analyses that removed conversions confirmed these findings.

CONCLUSIONS

With a 6.1% absolute difference, a strong trend toward improved 5-year survival was observed with on-pump CABG for medically treated diabetic patients. No off-pump advantage was found for any 5-year end points. A future clinical trial now appears warranted to rigorously compare off-pump versus on-pump longer term outcomes for diabetic patients.

Effect of early percutaneous coronary intervention on one-year risk of pneumonia and pneumonia-related adverse outcomes in patients with acute myocardial infarction

AIMS

The aim of this study was to investigate the association between early percutaneous coronary intervention (PCI) and pneumonia risk in patients with acute myocardial infarction (AMI) by using Taiwan's National Health Insurance Research Database (NHIRD).

METHODS AND RESULTS

In total, 4,732 patients with non-ST-elevation myocardial infarction (NSTEMI) and 5,465 with ST-elevation myocardial infarction (STEMI) who had received PCI during AMI hospitalisation (early PCI) were evaluated. Patients who did not receive PCI during AMI hospitalisation (deferred PCI) were matched through propensity score matching. The incidence rates (per 100 person-months) of pneumonia hospitalisation, pneumonia-related respiratory failure, and pneumonia-related death associated with early PCI in patients with NSTEMI were 0.36 (95% confidence interval [CI]: 0.32-0.42), 0.12 (95% CI: 0.10-0.16), and 0.08 (95% CI: 0.06-0.11), respectively. In patients with STEMI, the incidence rates (per 100 person-months) of the aforementioned adverse events were 0.16 (95% CI: 0.13-0.20), 0.04 (95% CI: 0.03-0.06), and 0.02 (95% CI: 0.01-0.04), respectively. After adjustment for patients' clinical variables, early PCI was associated with reduced risks of pneumonia hospitalisation (adjusted hazard ratio [aHR] 0.54, 95% CI: 0.43-0.68, p<0.001), pneumonia-related respiratory failure (aHR 0.54, 95% CI: 0.35-0.84, p=0.006), and pneumonia-related death (aHR 0.29, 95% CI: 0.17-0.52, p<0.001) in patients with NSTEMI. In patients with STEMI, early PCI was beneficial for pneumonia hospitalisation (aHR 0.62, 95% CI: 0.45- 0.86, p=0.004).

CONCLUSIONS

Early PCI might reduce the risk of pneumonia hospitalisation in patients with AMI.

Determinants of Variation in Pneumonia Rates After Coronary Artery Bypass Grafting

BACKGROUND

Although conventional wisdom suggests that differences in patient risk profiles drive variability in postoperative pneumonia rates after coronary artery bypass grafting (CABG), this teaching has yet to be empirically tested. We determined to what extent patient risk factors account for hospital variation in pneumonia rates.

METHODS

We studied 324,085 patients undergoing CABG between July 1, 2011, and December 31, 2013, across 998 hospitals using The Society of Thoracic Surgeons Adult Cardiac Database. We developed 5 models to estimate our incremental ability to explain hospital variation in pneumonia rates. Model 1 contained patient demographic characteristics and admission status, while Model 2 added patient risk factors. Model 3 added measures of pulmonary function, Model 4 added measures of cardiac anatomy and function and medications, and Model 5 further added measures of intraoperative and postoperative care.

RESULTS

Although 9,175 patients (2.83%) experienced pneumonia, the median estimated distribution of pneumonia rates across hospitals was 2.5% (25th to 75th percentile: 1.5% to 4.0%). Wide variability in pneumonia rates was evident, with some hospitals having rates more than 6 times higher than others (10th to 90th percentile: 1.0% to 6.1%). Among all five models, Model 2 accounted for the most variability at 4.24%. In total, 2.05% of hospital variation in pneumonia rates was explained collectively by traditional patient factors, leaving 97.95% of variation unexplained.

CONCLUSIONS

Our findings suggest that patient risk profiles only account for a fraction of hospital variation in pneumonia rates; enhanced understanding of other contributory factors (eg, processes of care) is required to lessen the likelihood of such nosocomial infections.

Complications of CO2 insufflation during endoscopic vein harvesting

Over the past few decades, the use of endoscopic harvest of the saphenous vein has gained popularity due to a significant reduction in rates of wound infection and improved cosmesis. The widespread adoption of this technique has introduced a set of complications associated with the use CO₂ insufflation which facilitates exposure during the vein harvest. We describe a case of pneumoperitoneum with systemic acidosis and subcutaneous air following endoscopic vein harvest for coronary artery bypass grafting and review the complications that may arise from CO₂ insufflation during endoscopic vein harvesting.

Cardiothoracic Critical Care

High-value CCC is rapidly evolving to meet the demands of increased patient acuity and to incorporate advances in technology. The high-performing CCC system and culture should aim to learn quickly and continuously improve. CCC demands a proactive, interactive, precise, an expert team, and continuity.

Pneumonia after cardiac surgery: Experience of the National Institutes of Health/Canadian Institutes of Health Research Cardiothoracic Surgical Trials Network

RATIONALE

Pneumonia remains the most common major infection after cardiac surgery despite numerous preventive measures.

OBJECTIVES

To prospectively examine the timing, pathogens, and risk factors, including modifiable management practices, for postoperative pneumonia and estimate its impact on clinical outcomes.

METHODS

A total of 5158 adult cardiac surgery patients were enrolled prospectively in a cohort study across 10 centers. All infections were adjudicated by an independent committee. Competing risk models were used to assess the association of patient characteristics and management practices with pneumonia within 65 days of surgery. Mortality was assessed by Cox proportional hazards model and length of stay by a multistate model.

MEASUREMENTS AND MAIN RESULTS

The cumulative incidence of pneumonia was 2.4%, 33% of which occurred after discharge. Older age, lower hemoglobin level, chronic obstructive pulmonary disease, steroid use, operative time, and left ventricular assist device/heart transplant were risk factors. Ventilation time (24-48 vs ≤24 hours; hazard ratio [HR], 2.83; 95% confidence interval [95% CI], 1.72-4.66; >48 hours HR, 4.67; 95% CI, 2.70-8.08), nasogastric tubes (HR, 1.80; 95% CI, 1.10-2.94), and each unit of blood cells transfused (HR, 1.16; 95% CI, 1.08-1.26) increased the risk of pneumonia. Prophylactic use of second-generation cephalosporins (HR, 0.66; 95% CI, 0.45-0.97) and platelet transfusions (HR, 0.49, 95% CI, 0.30-0.79) were protective. Pneumonia was associated with a marked increase in mortality (HR, 8.89; 95% CI, 5.02-15.75) and longer length of stay of 13.55 ± 1.95 days (bootstrap 95% CI, 10.31-16.58).

CONCLUSIONS

Pneumonia continues to impose a major impact on the health of patients after cardiac surgery. After we adjusted for baseline risk, several specific management practices were associated with pneumonia, which offer targets for quality improvement and further research.

A Preoperative Risk Model for Postoperative Pneumonia After Coronary Artery Bypass Grafting

BACKGROUND

Postoperative pneumonia is the most prevalent of all hospital-acquired infections after isolated coronary artery bypass graft surgery (CABG). Accurate prediction of a patient's risk of this morbid complication is hindered by its low relative incidence. In an effort to support clinical decision making and quality improvement, we developed a preoperative prediction model for postoperative pneumonia after CABG.

METHODS

We undertook an observational study of 16,084 patients undergoing CABG between the third quarter of 2011 and the second quarter of 2014 across 33 institutions participating in the Michigan Society of Thoracic and Cardiovascular Surgeons Quality Collaborative. Variables related to patient demographics, medical history, admission status, comorbid disease, cardiac anatomy, and the institution performing the procedure were investigated. Logistic regression through forward stepwise selection (p < 0.05 threshold) was utilized to develop a risk prediction model for estimating the occurrence of pneumonia. Traditional methods were used to assess the model's performance.

RESULTS

Postoperative pneumonia occurred in 3.30% of patients. Multivariable analysis identified 17 preoperative factors, including demographics, laboratory values, comorbid disease, pulmonary and cardiac function, and operative status. The final model significantly predicted the occurrence of pneumonia, and performed well (C-statistic: 0.74). These findings were confirmed through sensitivity analyses by center and clinically important subgroups.

CONCLUSIONS

We identified 17 readily obtainable preoperative variables associated with postoperative pneumonia. This model may be used to provide individualized risk estimation and to identify opportunities to reduce a patient's preoperative risk of pneumonia through prehabilitation.