Contemporary Training in American Critical Care Cardiology: Minnesota Critical Care Cardiology Education Summit: JACC Scientific Expert Panel.

This consensus statement emerges from collaborative efforts among leading figures in critical care cardiology throughout the United States, who met to share their collective expertise on issues faced by those active in or pursuing contemporary critical care cardiology education. The panel applied fundamentals of adult education and curriculum design, reviewed requisite training necessary to provide high-quality care to critically ill patients with cardiac pathology, and devoted attention to a purposeful approach emphasizing diversity, equity, and inclusion in developing this nascent field. The resulting paper offers a comprehensive guide for current trainees, with insights about the present landscape of critical care cardiology while highlighting issues that need to be addressed for continued advancement. By delineating future directions with careful consideration and intentionality, this Expert Panel aims to facilitate the continued growth and maturation of critical care cardiology education and practice.

Outcomes for Mechanically Ventilated Patients With Acute Myocardial Infarction Admitted to Medical vs Cardiac Intensive Care Units.

Background: Acute myocardial infarction (AMI) remains a common reason for admission to the intensive care unit (ICU). However, there is limited data comparing outcomes for patients with AMI admitted to specific ICUs. Objectives: The purpose of this study was to assess clinical outcomes between patients with AMI requiring invasive mechanical ventilation admitted to the medical ICU (MICU) compared to cardiac (CICU). Methods: We utilized the Vizient Clinical Data Base to identify patients with a primary diagnosis of AMI between October 2015 and December 2019 and requiring invasive mechanical ventilation. Using multivariable logistic regression, we compared clinical outcomes for patients admitted to the MICU vs CICU. Results: We identified 12,639 patients, 25.2% (n = 3,185) of which were admitted to a MICU and 74.8% (n = 9,454) to a CICU. Patients admitted to a CICU were more likely to present with STEMI (57.0% vs 42.8%), cardiogenic shock (46.0% vs 37.4%), and require mechanical circulatory support and vasoactive medications (all, P < 0.001). Median ventilator days were 4 days in both ICUs and not statistically different after multivariable adjustment (P = 0.81). In-hospital mortality was 42.7% compared to 41.3% for MICU vs CICU admissions, respectively (P = 0.15). After multivariable adjustment, CICU admission was associated with lower in-hospital mortality (OR: 0.85, 95% CI: 0.78-0.93, P = 0.001), which persisted when stratified by cardiogenic shock, cardiac arrest, STEMI, largest hospital size (>750 beds), and teaching hospitals (all, P < 0.05). Conclusions: Admission to the CICU, as compared to MICU, was associated with lower in-hospital mortality for patients with AMI. These findings may support optimal triage of critically ill patients with AMI.

Epidemiology of Cardiogenic Shock Using the Shock Academic Research Consortium (SHARC) Consensus Definitions.

BACKGROUND: The Shock Academic Research Consortium (SHARC) recently proposed pragmatic consensus definitions to standardize classification of cardiogenic shock (CS) in registries and clinical trials. We aimed to describe contemporary CS epidemiology using the SHARC definitions in a cardiac intensive care unit (CICU) population. METHODS: The Critical Care Cardiology Trials Network (CCCTN) is a multinational research network of advanced CICUs coordinated by the TIMI Study Group (Boston, MA). CS was defined as a cardiac disorder resulting in SBP<90mmHg for ≥30 minutes (or the need for vasopressors, inotropes, or mechanical circulatory support [MCS] to maintain SBP ≥90mmHg) with evidence of hypoperfusion. Primary etiologic categories included acute myocardial infarction-related CS (AMI-CS), heart failure-related CS (HF-CS), and non-myocardial (secondary) CS. Post-cardiotomy CS was not included. HF-CS was further subcategorized as de novo vs. acute-on-chronic HF-CS. Patients with both cardiogenic and non-cardiogenic components of shock were classified separately as mixed CS. RESULTS: Of 8,974 patients meeting shock criteria (2017-2023), 65% had isolated CS and 17% had mixed shock. Among patients with CS (n=5,869), 27% had AMI-CS (65% STEMI), 59% HF-CS (72% acute-on-chronic, 28% de novo), and 14% secondary CS. Patients with AMI-CS and de novo HF-CS were most likely to have had concomitant cardiac arrest (p<0.001). Patients with AMI-CS and mixed CS were most likely to present in more severe shock stages (SCAI D or E; p<0.001). Temporary MCS use was highest in AMI-CS (59%). In-hospital mortality was highest in mixed CS (48%), followed by AMI-CS (41%), similar in de novo HF-CS (31%) and secondary CS (31%), and lowest in acute-on-chronic HF-CS (25%; p<0.001). CONCLUSIONS: SHARC consensus definitions for CS classification can be pragmatically applied in contemporary registries and reveal discrete subpopulations of CS with distinct phenotypes and outcomes that may be relevant to clinical practice and future research.

Current practices in the management of temporary mechanical circulatory support: A survey of CICU directors in North America.

INTRODUCTION: Despite the growing use of temporary mechanical circulatory support (tMCS), little data exists to inform management and weaning of these devices. METHODS: We performed an online survey among cardiac intensive care unit directors in North America to examine current practices in the management of patients treated with intraaortic balloon pump and Impella. RESULTS: We received responses from 84% of surveyed centers (n=37). Our survey focused on three key aspects of daily management: 1. Hemodynamic monitoring; 2. Hemocompatibility; and 3. Weaning and removal. We found substantial variability surrounding all three areas of care. CONCLUSION: Our findings highlight the need for consensus around practices associated with improved outcomes in patients treated with tMCS.

Arterial hyperoxia and mortality in the cardiac intensive care unit.

BACKGROUND: Arterial hyperoxia (hyperoxemia), defined as a high arterial partial pressure of oxygen (PaO2), has been associated with adverse outcomes in critically ill populations, but has not been examined in the cardiac intensive care unit (CICU). We evaluated the association between exposure to hyperoxia on admission with in-hospital mortality in a mixed CICU cohort. METHODS: We included unique Mayo Clinic CICU patients admitted from 2007 to 2018 with admission PaO2 data (defined as the PaO2 value closest to CICU admission) and no hypoxia (PaO2 < 60mmHg). The admission PaO2 was evaluated as a continuous variable and categorized (60-100 mmHg, 101-150 mmHg, 151-200 mmHg, 201-300 mmHg, >300 mmHg). Logistic regression was used to evaluate predictors of in-hospital mortality before and after multivariable adjustment. RESULTS: We included 3,368 patients with a median age of 70.3 years; 70.3% received positive-pressure ventilation. The median PaO2 was 99 mmHg, with a distribution as follows: 60-100 mmHg, 51.9%; 101-150 mmHg, 28.6%; 151-200 mmHg, 10.6%; 201-300 mmHg, 6.4%; >300 mmHg, 2.5%. A J-shaped association between admission PaO2 and in-hospital mortality was observed, with a nadir around 100 mmHg. A higher PaO2 was associated with increased in-hospital mortality (adjusted OR 1.17 per 100 mmHg higher, 95% CI 1.01-1.34, p = 0.03). Patients with PaO2 >300 mmHg had higher in-hospital mortality versus PaO2 60-100 mmHg (adjusted OR 2.37, 95% CI 1.41-3.94, p < 0.001). CONCLUSIONS: Hyperoxia at the time of CICU admission is associated with higher in-hospital mortality, primarily in those with severely elevated PaO2 >300 mmHg.

Temperature Control Parameters Are Important: Earlier Preinduction Is Associated With Improved Outcomes Following Out-of-Hospital Cardiac Arrest.

STUDY OBJECTIVE: Temperature control trials in cardiac arrest patients have not reliably conferred neuroprotective benefit but have been limited by inconsistent treatment parameters. To evaluate the presence of a time dependent treatment effect, we assessed the association between preinduction time and clinical outcomes. METHODS: In this retrospective, single academic center study between 2014 and 2022, consecutive out-of-hospital cardiac arrest (OHCA) patients treated with temperature control were identified. Preinduction was defined as the time from hospital arrival to initiation of a closed-loop temperature feedback device [door to temperature control initiation time], and early door to temperature control device time was defined a priori as <3 hours. We assessed the association between good neurologic outcome (cerebral performance category 1 to 2) and door to temperature control device time using logistic regression. The proportion of patients who survived to hospital discharge was evaluated as a secondary outcome. A sensitivity analysis using inverse probability treatment weighting, created using a propensity score, was performed to minimize measurable confounding. RESULTS: Three hundred and forty-seven OHCA patients were included; the early door to temperature control device cohort included 75 (21.6%) patients with a median (interquartile range) door to temperature control device time of 2.50 (2.03 to 2.75) hours, whereas the late door to temperature control device cohort included 272 (78.4%) patients with a median (interquartile range) door to temperature control device time of 5.18 (4.19 to 6.41) hours. In the multivariable logistic regression model, early door to temperature control device time was associated with improved good neurologic outcome and survival before [adjusted odds ratio (OR) (95% confidence interval) 2.36 (1.16 to 4.81) and 3.02 (1.54 to 6.02)] and after [adjusted OR (95% confidence interval) 1.95 (1.19 to 3.79) and 2.14 (1.33 to 3.36)] inverse probability of treatment weighting, respectively. CONCLUSION: In our study of OHCA patients, a shorter preinduction time for temperature control was associated with improved good neurologic outcome and survival. This finding may indicate that early initiation in the emergency department will confer benefit. Our findings are hypothesis generating and need to be validated in future prospective trials.

Stress Ulcer Prophylaxis in Mechanically Ventilated Patients With Acute Myocardial Infarction.

Background: Proton pump inhibitors (PPIs) and histamine type 2-receptor blockers (H2Bs) are commonly used for stress ulcer prophylaxis among patients requiring invasive mechanical ventilation (IMV). Recent studies suggest an increased mortality associated with PPIs compared to H2Bs, but these studies poorly represent patients with cardiovascular disease or acute myocardial infarction (AMI). Objectives: The aim of this study was to compare outcomes related to stress ulcer prophylaxis with PPIs compared to H2Bs in patients with AMI requiring IMV. Methods: We queried the Vizient Clinical Data Base for adults aged ≥18 years admitted between October 2015 and December 2019 with a primary diagnosis of AMI and requiring IMV. Using multivariable logistic regression, we assessed for the association between stress ulcer prophylaxis and in-hospital mortality. Results: Including 11,252 patients with AMI requiring IMV, 66.7% (n = 7,504) received PPIs and 33.3% (n = 3,748) received H2Bs. Age, sex, and the proportion of patients presenting with ST-segment elevation myocardial infarction or cardiogenic shock were similar between groups (all, P > 0.05). Compared to PPIs, patients receiving H2Bs had a lower mortality (41.5% vs 43.5%, P = 0.047), which was not statistically significant after multivariate adjustment (odds ratio 0.97; 95% confidence interval: 0.89-1.06, P = 0.49). In unadjusted and adjusted analyses, H2Bs use was associated with fewer ventilator days, less ventilator-associated pneumonia, and lower hospitalization cost but similar Clostridium difficile infections. Conclusions: Among patients with AMI requiring IMV in this observation cohort study, there was no difference in mortality among patients receiving H2Bs vs PPIs for stress ulcer prophylaxis despite fewer ventilator days and lower ventilator-associated pneumonia in those receiving H2Bs.

Tracheostomy in Patients with Acute Myocardial Infarction and Respiratory Failure.

OBJECTIVE: Patients with acute myocardial infarction (AMI) complicated by respiratory failure require antiplatelet regimens which often cannot be stopped and may increase bleeding from tracheostomy. However, there is limited available data on both the proportion of patients undergoing tracheostomy and the impact on antiplatelet regimens on outcomes. METHODS: Utilizing the Vizient® Clinical Data Base, we identified patients ≥18 years admitted from 2015 to 2019 with a primary diagnosis of AMI and requiring invasive mechanical ventilation (IMV). We assessed for the incidence of patients undergoing tracheostomy, outcomes stratified by the timing of tracheostomy (≤10 vs >10 days), and the association between dual antiplatelet therapy (DAPT) use and in-hospital mortality. RESULTS: We identified 26 435 patients presenting with AMI requiring IMV. The mean (SD) age was 66.8 (12.3) years and 33.4% were women. The incidence of tracheostomy was 6.0% (n = 1573), and the median IMV time to tracheostomy was 12 days, 55.6% of which underwent percutaneous and 44.4% underwent open tracheostomy. Over 90% (n = 1424) underwent tracheostomy (>10 days) and had a similar mortality when compared to early (≤10 days) tracheostomy (22.5% vs 22.8%, P = 0.94). On the day of tracheostomy, only 24.7% were given DAPT, which was associated with a lower mortality than those not on DAPT (17.4% vs 23.7%, P = 0.01). After multivariable adjustment, DAPT use on the day of tracheostomy remained associated with lower in-hospital mortality (odds ratio 0.68; 95% confidence interval: 0.49-0.94, P = 0.02). Tracheostomy complications were not different between groups (P > 0.05), but more patients in the DAPT group required post-tracheostomy blood transfusions (5.6% vs 2.7%, P = 0.01). CONCLUSION: Approximately 1 in 20 intubated AMI patients requires tracheostomy. The lack of DAPT interruption on the day of tracheostomy but not the timing of tracheostomy was associated with a lower in-hospital mortality. Our results suggest that DAPT should not be a barrier to tracheostomy for patients with AMI.

Noninvasive Ventilation in the Cardiac Intensive Care Unit.

Over the last several decades, the cardiac intensive care unit (CICU) has seen an increase in the complexity of the patient population and etiologies requiring CICU admission. Currently, respiratory failure is the most common reason for admission to the contemporary CICU. As a result, noninvasive ventilation (NIV), including noninvasive positive-pressure ventilation and high-flow nasal cannula, has been increasingly utilized in the management of patients admitted to the CICU. In this review, we detail the different NIV modalities and summarize the evidence supporting their use in conditions frequently encountered in the CICU. We describe the unique pathophysiologic interactions between positive pressure ventilation and left and/or right ventricular dysfunction. Additionally, we discuss the evidence and strategies for utilization of NIV as a method to reduce extubation failure in patients who required invasive mechanical ventilation. Lastly, we examine unique considerations for managing respiratory failure in certain, high-risk patient populations such as those with right ventricular failure, severe valvular disease, and adult congenital heart disease. Overall, it is critical for clinicians who practice in the CICU to be experts with the application, risks, benefits, and modalities of NIV in cardiac patients with respiratory failure.

Complex Heart-Lung Ventilator Emergencies in the CICU.

This review aims to enhance the comprehension and management of cardiopulmonary interactions in critically ill patients with cardiovascular disease undergoing mechanical ventilation. Highlighting the significance of maintaining a delicate balance, this article emphasizes the crucial role of adjusting ventilation parameters based on both invasive and noninvasive monitoring. It provides recommendations for the induction and liberation from mechanical ventilation. Special attention is given to the identification of auto-PEEP (positive end-expiratory pressure) and other situations that may impact hemodynamics and patients' outcomes.

Early Serial Assessment of Aggregate Vasoactive Support and Mortality in Cardiogenic Shock: Insights From the Critical Care Cardiology Trials Network Registry.

BACKGROUND: Associations of early changes in vasoactive support with cardiogenic shock (CS) mortality remain incompletely defined. METHODS: The Critical Care Cardiology Trials Network is a multicenter registry of cardiac intensive care units. Patients admitted with CS (2018-2023) had vasoactive dosing assessed at 4 and 24 hours from cardiac intensive care unit admission and quantified by the vasoactive-inotropic score (VIS). Prognostic associations of VIS at both time points, as well as change in VIS from 4 to 24 hours, were examined. Interaction testing was performed based on mechanical circulatory support status. RESULTS: Among 3665 patients, 82% had a change in VIS <10, with 7% and 11% having a ≥10-point increase and decrease from 4 to 24 hours, respectively. The 4 and 24-hour VIS were each associated with cardiac intensive care unit mortality (13%-45% and 11%-73% for VIS <10 to ≥40, respectively; Ptrend <0.0001 for each). Stratifying by the 4-hour VIS, changes in VIS from 4 to 24 hours had a graded association with mortality, ranging from a 2- to >4-fold difference in mortality comparing those with a ≥10-point increase to ≥10-point decrease in VIS (Ptrend <0.0001). The change in VIS alone provided good discrimination of cardiac intensive care unit mortality (C-statistic, 0.72 [95% CI, 0.70-0.75]) and improved discrimination of the 24-hour Sequential Organ Failure Assessment score (0.72 [95% CI, 0.69-0.74] to 0.76 [95% CI, 0.74-0.78]) and the clinician-assessed Society for Cardiovascular Angiography and Interventions shock stage (0.72 [95% CI, 0.70-0.74] to 0.77 [95% CI, 0.75-0.79]). Although present in both groups, the mortality risk associated with VIS was attenuated in patients managed with versus without mechanical circulatory support (odds ratio per 10-point higher 24-hour VIS, 1.36 [95% CI, 1.23-1.49] versus 1.84 [95% CI, 1.69-2.01]; Pinteraction <0.0001). CONCLUSIONS: Early changes in the magnitude of vasoactive support in CS are associated with a gradient of risk for mortality. These data suggest that early VIS trajectory may improve CS prognostication, with the potential to be leveraged for clinical decision-making and research applications in CS.

Need for a Cardiogenic Shock Team Collaborative-Promoting a Team-Based Model of Care to Improve Outcomes and Identify Best Practices.

Cardiogenic shock continues to carry a high mortality rate despite contemporary care, with no breakthrough therapies shown to improve survival over the past few decades. It is a time-sensitive condition that commonly results in cardiovascular complications and multisystem organ failure, necessitating multidisciplinary expertise. Managing patients with cardiogenic shock remains challenging even in well-resourced settings, and an important subgroup of patients may require cardiac replacement therapy. As a result, the idea of leveraging the collective cognitive and procedural proficiencies of multiple providers in a collaborative, team-based approach to care (the "shock team") has been advocated by professional societies and implemented at select high-volume clinical centers. A slowly maturing evidence base has suggested that cardiogenic shock teams may improve patient outcomes. Although several registries exist that are beginning to inform care, particularly around therapeutic strategies of pharmacologic and mechanical circulatory support, none of these are currently focused on the shock team approach, multispecialty partnership, education, or process improvement. We propose the creation of a Cardiogenic Shock Team Collaborative-akin to the successful Pulmonary Embolism Response Team Consortium-with a goal to promote sharing of care protocols, education of stakeholders, and discovery of how process and performance may influence patient outcomes, quality, resource consumption, and costs of care.

Propofol vs etomidate for induction prior to invasive mechanical ventilation in patients with acute myocardial infarction.

BACKGROUND: Patients with acute myocardial infarction (AMI) requiring invasive mechanical ventilation (IMV) have a high mortality. However, little is known regarding the impact of induction agents, used prior to IMV, on clinical outcomes in this population. We assessed for the association between induction agent and mortality in patients with AMI requiring IMV. METHODS: We compared clinical outcomes between those receiving propofol compared to etomidate for induction among adults with AMI between October 2015 and December 2019 using the Vizient® Clinical Data Base, a multicenter, US national database. We used inverse probability treatment weighting (IPTW) to assess for the association between induction agent and in-hospital mortality. RESULTS: We identified 5,147 patients, 1,386 (26.9%) of received propofol and 3,761 (73.1%) received etomidate for IMV induction. The mean (SD) age was 66.1 (12.4) years, 33.0% were women, and 51.6% and 39.8% presented with STEMI and cardiogenic shock, respectively. Patients in the propofol group were more likely to require preintubation vasoactive medication and mechanical circulatory support (both, P < .05). Utilization of propofol was associated with lower mortality compared to etomidate (32.3% vs 36.1%, P = .01). After propensity weighting, propofol use remained associated with lower mortality (weighted mean difference -4.7%; 95% confidence interval: -7.6% to -1.8%, P = .002). Total cost, ventilator days, and length of stay were higher in the propofol group (all, P < .001). CONCLUSIONS: Induction with propofol, compared with etomidate, was associated with lower mortality for patients with AMI requiring IMV. Randomized trials are needed to determine the optimal induction agent for this critically ill patient population.

Research Priorities in Critical Care Cardiology: JACC Expert Panel.

Over the last several decades, the cardiac intensive care unit (CICU) has seen a substantial evolution in the patient population, comorbidities, and diagnoses. However, the generation of high-quality evidence to manage these complex and critically ill patients has been slow. Given the scarcity of clinical trials focused on critical care cardiology (CCC), CICU clinicians are often left to extrapolate from studies that either exclude or poorly represent the patient population admitted to CICUs. The lack of high-quality evidence and limited guidance from society guidelines has led to significant variation in practice patterns for many of the most common CICU diagnoses. Several barriers, both common to critical care research and unique to CCC, have impeded progress. In this multinational perspective, we describe key areas of priority for CCC research, current challenges for investigation in the CICU, and essential elements of a path forward for the field.

Development and validation of a novel score to predict brain death after out-of-hospital cardiac arrest.

BACKGROUND AND OBJECTIVES: Brain death (BD) occurs in 9-24% of successfully resuscitated out-of-hospital cardiac arrests (OHCA). To predict BD after OHCA, we developed a novel brain death risk (BDR) score. METHODS: We identified independent predictors of BD after OHCA in a retrospective, single academic center cohort between 2011 and 2021. The BDR score ranges from 0 to 7 points and includes: non-shockable rhythm (1 point), drug overdose as etiology of arrest (1 point), evidence of grey-white differentiation loss or sulcal effacement on head computed tomography (CT) radiology report within 24 hours of arrest (2 points), Full-Outline-Of-UnResponsiveness (FOUR) score of 0 (2 points), FOUR score 1-5 (1 point), and age <45 years (1 point). We internally validated the BDR score using k-fold cross validation (k = 8) and externally validated the score at an independent academic center. The main outcome was BD. RESULTS: The development cohort included 362OHCA patients, of whom 18% (N = 58) experienced BD. Internal validation provided an area under the receiving operator characteristic curve (AUC) (95% CI) of 0.931 (0.905-0.957). In the validation cohort, 19.8% (N = 17) experienced BD. The AUC (95% CI) was 0.849 (0.765-0.933). In both cohorts, a BDR score >4 was the optimal cut off (sensitivity 0.903 and 0.882, specificity 0.830 and 0.652, in the development and validation cohorts respectively). DISCUSSION: The BDR score identifies those at highest risk for BD after OHCA. Our data suggest that a BDR score >4 is the optimal cut off.

Prognostic significance of haemodynamic parameters in patients with cardiogenic shock.

AIMS: Invasive haemodynamic assessment with a pulmonary artery catheter is often used to guide the management of patients with cardiogenic shock (CS) and may provide important prognostic information. We aimed to assess prognostic associations and relationships to end-organ dysfunction of presenting haemodynamic parameters in CS. METHODS AND RESULTS: The Critical Care Cardiology Trials Network is an investigator-initiated multicenter registry of cardiac intensive care units (CICUs) in North America coordinated by the TIMI Study Group. Patients with CS (2018-2022) who underwent invasive haemodynamic assessment within 24 h of CICU admission were included. Associations of haemodynamic parameters with in-hospital mortality were assessed using logistic regression, and associations with presenting serum lactate were assessed using least squares means regression. Sensitivity analyses were performed excluding patients on temporary mechanical circulatory support and adjusted for vasoactive-inotropic score. Among the 3603 admissions with CS, 1473 had haemodynamic data collected within 24 h of CICU admission. The median cardiac index was 1.9 (25th-75th percentile, 1.6-2.4) L/min/m2 and mean arterial pressure (MAP) was 74 (66-86) mmHg. Parameters associated with mortality included low MAP, low systolic blood pressure, low systemic vascular resistance, elevated right atrial pressure (RAP), elevated RAP/pulmonary capillary wedge pressure ratio, and low pulmonary artery pulsatility index. These associations were generally consistent when controlling for the intensity of background pharmacologic and mechanical haemodynamic support. These parameters were also associated with higher presenting serum lactate. CONCLUSION: In a contemporary CS population, presenting haemodynamic parameters reflecting decreased systemic arterial tone and right ventricular dysfunction are associated with adverse outcomes and systemic hypoperfusion.

Pulmonary Artery Catheter Use and Mortality in the Cardiac Intensive Care Unit.

BACKGROUND: The appropriate use of pulmonary artery catheters (PACs) in critically ill cardiac patients remains debated. OBJECTIVES: The authors aimed to characterize the current use of PACs in cardiac intensive care units (CICUs) with attention to patient-level and institutional factors influencing their application and explore the association with in-hospital mortality. METHODS: The Critical Care Cardiology Trials Network is a multicenter network of CICUs in North America. Between 2017 and 2021, participating centers contributed annual 2-month snapshots of consecutive CICU admissions. Admission diagnoses, clinical and demographic data, use of PACs, and in-hospital mortality were captured. RESULTS: Among 13,618 admissions at 34 sites, 3,827 were diagnosed with shock, with 2,583 of cardiogenic etiology. The use of mechanical circulatory support and heart failure were the patient-level factors most strongly associated with a greater likelihood of the use of a PAC (OR: 5.99 [95% CI: 5.15-6.98]; P < 0.001 and OR: 3.33 [95% CI: 2.91-3.81]; P < 0.001, respectively). The proportion of shock admissions with a PAC varied significantly by study center ranging from 8% to 73%. In analyses adjusted for factors associated with their placement, PAC use was associated with lower mortality in all shock patients admitted to a CICU (OR: 0.79 [95% CI: 0.66-0.96]; P = 0.017). CONCLUSIONS: There is wide variation in the use of PACs that is not fully explained by patient level-factors and appears driven in part by institutional tendency. PAC use was associated with higher survival in cardiac patients with shock presenting to CICUs. Randomized trials are needed to guide the appropriate use of PACs in cardiac critical care.