Pilot - Peri-operative Beta Blockade

Perioperative cardiac adverse events [heart injuries caused by general anesthesia and surgical procedures] are a significant public health issue, with more than 60,000 deaths per annum in patients having surgery for non-heart related issues. There are virtually no evidence-based medical strategies for effective prevention of these events. Preoperative drug treatment with beta blockade drugs used for high blood pressure, perioperative therapy with lipid lowering drugs such as statins, alpha-receptor agonists such as clonidine used for high blood pressure, and aspirin have all been investigated as potential mitigating treatments, but without positive clinical outcomes and, in some cases, creating more hemodynamic instabilities that result in heart injury. In light of this, investigators propose to evaluate the safety and efficacy of using increasing doses of beta blockade drugs immediately after surgery and to assess the value of high-sensitivity cardiac troponin level testing of the blood in predicting those patients who would benefit most from perioperative beta blocker therapy.

Postsurgical: 5mg metoprolol, IV, prior to extubation, every 5 minutes to achieve target heart rate of 65/min, up to 15mg; then 25mg metoprolol, oral, every 8 hours for 72 hours.

Inclusion Criteria: Age >50 years American Society of Anesthesiologists (ASA) risk status III-IV Revised Cardiac Risk Index ≥2 β-blocker naïve (not having received β-blocker within 30 days prior to surgery) Previously diagnosed coronary artery disease (CAD) or at high risk for CAD: History of peripheral vascular disease, or Diabetes and currently on oral anti-diabetic drug or insulin therapy, or Chronic renal failure (eGFR <30 m/min) Major non-cardiac surgery under general anesthesia Exclusion Criteria: History of stroke Heart rate <55bpm Heart failure Second or third degree AV block without pacemaker Active asthma or COPD Anemia [Hb<9g/dL] Allergy to beta-blockade drugs Hemodynamic instability Uncontrolled hemorrhage Unwilling or unable to give consent for participation