CATIS: Corticosteroids for Atrial Fibrillation after Cardiac Surgery (2007)

“In patients undergoing cardiac surgery, a short course of perioperative corticosteroids did not result in a lower incidence of postoperative atrial fibrillation.”

  • The CATIS Investigators

1. Publication Details

  • Trial Title: Corticosteroid Therapy for the Prevention of Atrial Fibrillation After Cardiac Surgery: A Randomized Controlled Trial
  • Citation: Halonen J, Halonen P, Järvinen O, et al. Corticosteroid therapy for the prevention of atrial fibrillation after cardiac surgery: a randomized controlled trial. JAMA. 2007;297(14):1562-1567. DOI: 10.1001/jama.297.14.1562
  • Published: April 11, 2007, in The Journal of the American Medical Association (JAMA)
  • Author: Jari Halonen, M.D.
  • Funding: The Finnish Foundation for Cardiovascular Research and others.

2. Keywords

  • Postoperative Atrial Fibrillation (POAF), Cardiac Surgery, Corticosteroids, Hydrocortisone, Randomized Controlled Trial

3. The Clinical Question

  • In adult patients undergoing cardiac surgery with cardiopulmonary bypass (Population), does perioperative treatment with intravenous hydrocortisone (Intervention) compared to placebo (Comparison) reduce the incidence of postoperative atrial fibrillation (POAF) (Outcome)?

4. Background and Rationale

  • Existing Knowledge: Postoperative atrial fibrillation (POAF) is a very common complication after cardiac surgery, leading to increased risks of stroke, longer hospital stays, and higher costs. The inflammatory response to surgery and cardiopulmonary bypass was believed to be a key trigger for POAF.
  • Knowledge Gap: Corticosteroids, with their potent anti-inflammatory effects, were a logical potential therapy to prevent POAF. However, evidence from previous small, underpowered trials was conflicting, and there was no definitive evidence from a large randomized controlled trial to guide practice.
  • Proposed Hypothesis: The authors hypothesized that perioperative hydrocortisone would be superior to placebo in reducing the incidence of POAF after cardiac surgery.

5. Study Design and Methods

  • Design: A single-center, prospective, randomized, double-blind, placebo-controlled trial (used to test the effectiveness of interventions).
  • Setting: A single university hospital in Finland.
  • Trial Period: Enrollment ran from October 2003 to December 2005.
  • Population:
    • Inclusion Criteria: Adult patients (≥18 years) scheduled for elective or urgent cardiac surgery requiring cardiopulmonary bypass.
    • Exclusion Criteria: Included pre-existing atrial fibrillation, recent myocardial infarction, severe heart failure (LVEF < 30%), and contraindications to corticosteroids.
  • Intervention: Patients received intravenous hydrocortisone (100 mg) before surgery, followed by 100 mg every 8 hours for 3 days.
  • Control: Patients received a matching intravenous placebo (0.9% saline) on the same schedule.
  • Management Common to Both Groups: All patients received standard anesthetic and surgical care, including routine beta-blocker therapy unless contraindicated.
  • Power and Sample Size: The authors calculated that a sample size of 240 patients would be required to have 80% power to detect a 20% absolute risk reduction in the incidence of POAF. (Power is a study’s ability to find a real difference between treatments if one truly exists; 80% is the standard accepted level for clinical trials).
  • Outcomes:
    • Primary Outcome: The incidence of postoperative atrial fibrillation during the hospital stay.
    • Secondary Outcomes: Included the time to onset of AF, length of hospital stay, and rates of postoperative complications.

6. Key Results

  • Enrollment and Baseline: 241 patients were randomized (121 to hydrocortisone and 120 to placebo). The groups were well-matched at baseline.
  • Trial Status: The trial was completed as planned.
  • Primary Outcome: There was no significant difference in the incidence of postoperative atrial fibrillation. POAF occurred in 39 of 121 patients (32.2%) in the hydrocortisone group and in 40 of 120 patients (33.3%) in the placebo group (p=0.86).
  • Secondary Outcomes: There were no significant differences between the groups in any of the secondary outcomes, including time to onset of AF or length of hospital stay.
  • Adverse Events: The study monitored for postoperative complications. There were no significant differences in the rates of major adverse events such as stroke, deep sternal wound infection, or gastrointestinal bleeding between the hydrocortisone and placebo groups.

7. Medical Statistics

  • Analysis Principle: The trial was analyzed using an intention-to-treat principle.
  • Statistical Tests Used: The primary outcome was analyzed using a chi-square test.
  • Primary Outcome Analysis: The primary outcome was a comparison of the proportions of patients who developed POAF between the two groups.
  • Key Statistic(s) Reported: The key statistics were the absolute incidence rates and the associated P-value.
  • Interpretation of Key Statistic(s):
    • P-value: The p-value of 0.86 is much higher than the 0.05 threshold, indicating that the very small difference in the incidence of POAF between the groups was not statistically significant and was very likely due to chance (a result is conventionally considered statistically significant if the p-value is less than 0.05).
  • Clinical Impact Measures: As the trial was neutral (showed no difference), ARR and NNT are not applicable.
  • Subgroup Analyses: No significant differences were found in any of the pre-specified subgroups.

8. Strengths of the Study

  • Study Design and Conduct: The randomized, double-blind, placebo-controlled design is the gold standard for minimizing selection and performance bias.
  • Statistical Power: The study was adequately powered for its primary outcome.
  • Patient-Centered Outcomes: The primary outcome of POAF is a clinically important and relevant endpoint.

9. Limitations and Weaknesses

  • Internal Validity (Bias):: The study was well-conducted with a low risk of bias.
  • External Validity (Generalizability): The single-center design is a significant limitation, as the results may not be applicable to other centers with different patient populations or surgical practices.
  • Other: The study tested only one specific corticosteroid (hydrocortisone) and one specific dosing regimen.

10. Conclusion of the Authors

  • In patients undergoing cardiac surgery, a short perioperative course of hydrocortisone did not reduce the incidence of postoperative atrial fibrillation.

11. To Summarize

  • Impact on Current Practice: This high-quality trial provided strong evidence that refuted the hypothesis that a simple, short course of corticosteroids could prevent POAF. It discouraged the routine use of this strategy.
  • Specific Recommendations:
    • Patient Selection: For adult patients undergoing routine cardiac surgery.
    • Actionable Intervention: The results do not support the use of perioperative hydrocortisone for the sole purpose of preventing POAF.
  • What This Trial Does NOT Mean: This trial does NOT mean that inflammation plays no role in POAF, nor that other anti-inflammatory strategies might not be effective.
  • Implementation Caveats: The findings of this trial should discourage the use of this specific hydrocortisone protocol for POAF prophylaxis.

12. Context and Related Studies

  • Building on Previous Evidence: The CATIS trial (2007) was designed to provide a more definitive answer to a question that had been explored in many smaller, less conclusive studies.
  • Influence on Subsequent Research: The definitive neutral finding of this trial, along with others, has led to a shift in research towards other prophylactic strategies for POAF, such as amiodarone, colchicine, and different pacing strategies.

13. Unresolved Questions & Future Directions

  • Unresolved Questions: This trial did not address whether other corticosteroid regimens or other anti-inflammatory agents might be effective.
  • Future Directions: Future research continues to explore the complex pathophysiology of POAF and to test other novel preventative strategies.

14. External Links

15. Framework for Critical Appraisal

  • Clinical Question: The research question was highly relevant, addressing a very common and clinically important postoperative complication.
  • Methods: The study design was robust (double-blind RCT), which is a key strength. The main methodological weakness is the single-center design, which limits the generalizability of the findings.
  • Results: The study reported a clear neutral finding for its primary outcome, with no statistically significant difference between the groups.
  • Conclusions and Applicability: The authors’ conclusion is a direct and fair reflection of the data. While the single-center design is a limitation, this trial provided strong evidence against the use of this specific steroid protocol and has been influential in guiding practice away from this ineffective therapy.

16. Disclaimer and Contact

  • This summary is provided by the Academic Committee of ESBICM (ACE) to facilitate the understanding of this study; readers are advised to refer to the original trial document for a deeper understanding. If you find any information incorrect, or missing, or it needs an update or have a request for a specific critical care trial summary, kindly write to us at academics[at]esbicm.org.
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