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Original Investigation
July 24, 2019

Demographics, Care Patterns, and Outcomes of Patients Admitted to Cardiac Intensive Care Units: The Critical Care Cardiology Trials Network Prospective North American Multicenter Registry of Cardiac Critical Illness

Author Affiliations
  • 1Levine Cardiac Intensive Care Unit, TIMI Study Group, Cardiovascular Division, Department of Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, Massachusetts
  • 2University of North Carolina at Chapel Hill, Chapel Hill
  • 3Division of Cardiology, Department of Critical Care Medicine, Department of Medicine, University of Alberta, Edmonton, Alberta, Canada
  • 4University of Florida, Gainesville, Florida
  • 5Department of Cardiology, Medstar Washington Hospital Center, Washington, DC
  • 6Mayo Clinic, Rochester, Minnesota
  • 7Lehigh Valley Health Network, Allentown, Pennsylvania
  • 8Cleveland Clinic Foundation, Cleveland, Ohio
  • 9Cooper University Hospital, Camden, New Jersey
  • 10Sulpizio Cardiovascular Center, University of California San Diego, La Jolla
  • 11University of Louisville, Louisville, Kentucky
  • 12Duke University, Durham, North Carolina
  • 13New York University Langone Health, New York
  • 14Virginia Commonwealth University, Richmond, Virginia
  • 15Peter Munk Cardiac Centre, Toronto General Hospital, University of Toronto, Toronto, Ontario, Canada
  • 16Johns Hopkins Hospital, Baltimore, Maryland
  • 17Rush University Medical Center, Chicago, Illinois
  • 18Clinical Center and Cardiology Branch, Critical Care Medicine Department, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland
JAMA Cardiol. Published online July 24, 2019. doi:10.1001/jamacardio.2019.2467
Key Points

Question  The evolving demographics, care patterns, and outcomes in the modern cardiac intensive care unit (CICU) are incompletely characterized.

Findings  In this study of 3049 consecutive admissions in the Critical Care Cardiology Trials Network (CCCTN), an investigator-initiated network of North American tertiary CICUs, while ACS and heart failure were the most common admission diagnoses, the range of acute cardiac conditions was diverse. The most common indications for CICU admission were respiratory insufficiency and shock; resource use was high, and the outcome was poor for many indications.

Meaning  The CCCTN provides a multicenter characterization of contemporary CICU care and could be used as a platform for observational studies and randomized clinical trials.


Importance  Single-center and claims-based studies have described substantial changes in the landscape of care in the cardiac intensive care unit (CICU). Professional societies have recommended research to guide evidence-based CICU redesigns.

Objective  To characterize patients admitted to contemporary, advanced CICUs.

Design, Setting, and Participants  This study established the Critical Care Cardiology Trials Network (CCCTN), an investigator-initiated multicenter network of 16 advanced, tertiary CICUs in the United States and Canada. For 2 months in each CICU, data for consecutive admissions were submitted to the central data coordinating center (TIMI Study Group). The data were collected and analyzed between September 2017 and 2018.

Main Outcomes and Measures  Demographics, diagnoses, management, and outcomes.

Results  Of 3049 participants, 1132 (37.1%) were women, 797 (31.4%) were individuals of color, and the median age was 65 years (25th and 75th percentiles, 55-75 years). Between September 2017 and September 2018, 3310 admissions were included, among which 2557 (77.3%) were for primary cardiac problems, 337 (10.2%) for postprocedural care, 253 (7.7%) for mixed general and cardiac problems, and 163 (4.9%) for overflow from general medical ICUs. When restricted to the initial 2 months of medical CICU admissions for each site, the primary analysis population included 3049 admissions with a high burden of noncardiovascular comorbidities. The top 2 CICU admission diagnoses were acute coronary syndrome (969 [31.8%]) and heart failure (567 [18.6%]); however, the proportion of acute coronary syndrome was highly variable across centers (15%-57%). The primary indications for CICU care included respiratory insufficiency (814 [26.7%]), shock (643 [21.1%]), unstable arrhythmia (521 [17.1%]), and cardiac arrest (265 [8.7%]). Advanced CICU therapies or monitoring were required for 1776 patients (58.2%), including intravenous vasoactive medications (1105 [36.2%]), invasive hemodynamic monitoring (938 [30.8%]), and mechanical ventilation (652 [21.4%]). The overall CICU mortality rate was 8.3% (95% CI, 7.3%-9.3%). The CICU indications that were associated with the highest mortality rates were cardiac arrest (101 [38.1%]), cardiogenic shock (140 [30.6%]), and the need for renal replacement therapy (51 [34.5%]). Notably, patients admitted solely for postprocedural observation or frequent monitoring had a mortality rate of 0.2% to 0.4%.

Conclusions and Relevance  In a contemporary network of tertiary care CICUs, respiratory failure and shock predominated indications for admission and carried a poor prognosis. While patterns of practice varied considerably between centers, a substantial, low-risk population was identified. Multicenter collaborative networks, such as the CCCTN, could be used to help redesign cardiac critical care and to test new therapeutic strategies.