I frequently get asked this question and so I will
answer it. How do you know that myocardial ischemia is not just
a marker for patients with higher risk? We know that patients
with risk factors have increased risk of myocardial ischemia.
We know that myocardial ischemia is associated with increased
incidence of perioperative cardiac events. We know that perioperative
myocardial ischemia is associated with an increase in 2 year mortality.
This graph demonstrates that patients with an episode of myocardial
ischemia have a higher cardiac morbidity and mortality than those
without myocardial ischemia. We also know that prophylactic perioperative
atenolol reduces the risk of myocardial ischemia. We also know
that discontinuing beta blockers in the perioperative period is
associated with an increase in the risk of myocardial ischemia,
myocardial infarction, and death.
We do not have definitive proof that episodes of
myocardial ischemia are bad for patients in the perioperative
period. However, the only way to determine the answer to this
question would be to randomize patients to elective perioperative
myocardial ischemia. No, one would do such an experiment and it
would be unethical. Despite the limitations in this last logical
connection, it very clear that myocardial ischemia is BAD for
patients, it leads to an increase in risk of MI and DEATH. Perioperative
beta blockers reduce the risk of MYOCARDIAL ISCHEMIA AND DEATH.
