Perioperative β-blockers

Earlier perioperative trials of β-blockers involved small numbers of patients undergoing a wide range of surgical procedures. In addition, different β-blockers were used without titration to a desired effect (target heart rate). This high degree of heterogeneity resulted in variable opinion regarding the use of β-blockers in the perioperative phase. Published meta-analyses included these small and relatively heterogeonus trials resulted in similar variable conclusions. Timing, location, and route of administration also complicate the desicion regarding the use of β-blockers perioperatively.

Areas of agreement

β-blockers should be continued in patients undergoing surgery who are already receiving β-blockers for any ACC/AHA class 1 recommendation. Interruption of therapy in these patients may lead to recurrent angina, arrhythmias, rebound hypertension, or other CV complications that may increase perioperative morbidity. The use of β-blockers is considered class 1 and class IIa in patients undergoing high risk vascular surgery with known coronary heart disease or have one or more clinical CV risk factors, respectively (Level of evidence= B, LOE B). This includes patients who were found to have myocardial ischemia on perioperative testing.

Barriers to effective use of perioperative β-blockers

• The titration of β-blockers dosage to achieve target resting heart rate of less 65 beats/min can pose logestical problems.
  • Many patients present to the preoperative medical clinic just one or few days prior to their scheduled procedure.
  • Titration of β-blockers dosage can results in hypotension, bradycardia, and other side effects.
  • The variable metabolic effects produced by β-blockers during their first pass through the hepatic venous circulation after absorption result in variable serum levels (and clinical effects) depending on the individual patient.

Recommendations

• The use of perioperative β-blockers should be limited to class 1 or class IIa recommendations (see baove).
• Patients should be seen earlier during the preoperative period for carefull titration of β-blockers.
• Clinicians should pay attention in regards to the use of concurrent medications that result in bradycardia and/or hypotension.

Johnfanisrour 02:03, 12 January 2009 (UTC) john fani srourJohnfanisrour 02:03, 12 January 2009 (UTC)