Steroids In caRdiac Surgery Trial (SIRS Trial)

• MI or Mortality at 30 days [ Time Frame: 30 days ] [ Designated as safety issue: No ]
• Mortality at 6 months [ Time Frame: 6 months ] [ Designated as safety issue: No ]

• New Onset Atrial Fibrillation
• Length of ICU Stay
• Length of Hospital Stay
• Bleeding/Transfusion Requirements
• Renal Failure
• Infection
• Wound Complications
• Gastrointestinal Complications

SIRS trial is a large simple study in which high-risk patients undergoing cardiac surgery requiring the use of cardiopulmonary bypass (CPB) are randomly allocated to receive a pulse dose of Methylprednisolone or a matching placebo. Cardiopulmonary bypass initiates a systemic inflammatory response that facilitates development of post-operative complications. SIRS will confirm or deny the potential clinical benefits of suppressing this response through the use of systemic steroids. Specifically, does 250 mg of intravenous Methylprednisolone given twice, once on anesthetic induction and again on CPB initiation, result in improved early survival and less myocardial infarction in high-risk cardiac surgery patients requiring CPB?

Cardiopulmonary bypass (CPB) is a commonly performed surgical procedure with over 500,000 per year in North America. CPB initiates a systemic inflammatory response characterized by both cell and protein activation. Platelets, neutrophils, monocytes, macrophages, coagulation, fibrinolytic, and kallikrein cascades all take part in what results in increased endothelial permeability, vascular, and parenchymal damage. These inflammatory pathways facilitate development of post-operative complications including thrombosis, myocardial injury and infarction, respiratory failure, renal and neurological dysfunction, bleeding disorders, altered liver function and ultimately, multiple organ failure.

In an attempt to minimize the deleterious effects of CPB, investigators have tested a variety of strategies in cardiac surgery ranging from the complete avoidance of CPB, to the use of biocompatible circuits and pharmacologic agents to abrogate the systemic response. Investigators have consistently demonstrated the efficacy of steroids as the most potent anti-inflammatory agent for use during CPB. In fact, from the available evidence, the 2004 AHA guidelines for coronary artery bypass grafting (CABG) "support liberal prophylactic use in patients undergoing extracorporeal circulation". However, the trials that do exist within this literature are focused on biochemical endpoints and are insufficiently powered to make conclusions on hard clinical endpoints. Our pilot RCT, SIRS I, demonstrated the efficacy of a low dose steroid protocol in the suppression of this inflammatory cascade. We hypothesize that this low dose protocol will yield clinical benefit while avoiding the potential adverse effects of steroids which are known to be dose dependent.

The primary aim of the SIRS trial is to determine if perioperative pulse dose Methylprednisolone results in improved early survival and less myocardial infarction in cardiac surgery requiring CPB. Additional secondary aims of the SIRS trial are to determine the effect of steroids on other clinical outcomes including length of stay, new onset atrial fibrillation, transfusion requirements, infectious, wound, and gastrointestinal complications.

The design of the SIRS trial is a prospective multicentre international double-blind placebo controlled randomized clinical trial. The sample size of 7500 patients will have 80% to 90% power to detect a 20-30% RRR for the primary outcome with an α=0.05 (two-sided), anticipating a 6% rate of death in the control arm. Our aim is to have 40 international centers participate which, recruiting at 5 patients per month, would complete recruitment in 36 months. This will be a large trial with a simple design and objective outcomes.

• Cardiac Surgical Procedures
• Cardiopulmonary Bypass
• Systemic Inflammatory Response Syndrome

• Drug: Methylprednisolone
  Given by IV in 2 doses (250 mg each dose for a total of 500 mg)
• Other: Placebo
  Given in 2 IV doses (approximately 4 ml of 0.9% normal saline solution in each dose)

• Experimental: Treatment
  500 mg of methylprednisolone divided into two intravenous doses of 250 mg each, one during anesthetic induction and the other on CPB initiation
  Intervention: Drug: Methylprednisolone
• Placebo Comparator: Placebo
  500 mg of matching placebo (normal saline solution) divided into two intravenous doses of 250 mg each, one during anesthetic induction and the other on CPB initiation
  Intervention: Other: Placebo

• Whitlock RP, Young E, Noora J, Farrokhyar F, Blackall M, Teoh KH. Pulse low dose steroids attenuate post-cardiopulmonary bypass SIRS; SIRS I. J Surg Res. 2006 May 15;132(2):188-94. Epub 2006 Mar 29.
• Whitlock RP, Rubens FD, Young E, Teoh KH. Pro: Steroids should be used for cardiopulmonary bypass. J Cardiothorac Vasc Anesth. 2005 Apr;19(2):250-4. Review. No abstract available.

Inclusion Criteria:

• Age ≥ 18 years
• Able to give informed consent
• Cardiopulmonary bypass for cardiac surgical procedure
• EuroSCORE ≥ 6

Exclusion Criteria:

• Use of systemic corticosteroids
• History of bacterial or fungal infection in last 30 days
• Allergy/intolerance to corticosteroids
• Will receive Aprotinin
• Previous participation in study