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January
1997
Review of Effect of Atenolol on Mortality and Cardiovascular
Morbidity After Noncardiac Surgery
Mangano et al.
NEJM 1996, 335:23: 1713.
Commentary by David
Lubarsky,
[ no abstract available ]
This is an extremely important study as it should directly influence the
anesthesiologist's approach to the care of the patient at risk for coronary
artery disease undergoing noncardiac surgery. Mangano's group had been instrumental
in defining the importance of using beta blockers to reduce perioperative
ischemia and associated myocardial infarctions. However, those earlier studies
left uanswered the question as to whether the use of beta blockers was simply
postponing a perioperative MI to a later time, rather than truly preventing
the MI.
This study shows that the benefits of aggressive perioperative administration
of atenolol significantly reduces perioperative mortality due to early cardiac
events (MI, dysrhythmia, congestive heart failure), and that that beneficial
effect is sustained for at least two years after surgery. The cardiac causes
of death are not being postponed by perioperative beta blocker therapy,
they are being truly prevented. 90% of patients treated with atenolol in
the hospital survived for two years, versus only 79% of those receiving
placebo.
As a result of this article, I expect that many of us will begin to use
atenolol 10 mg IV in 2 divided doses before surgery and then q 12 hours
until taking po, followed by doses of 50 -100 mg po throughout the course
of the at risk patient's hospitlization. It is important to note the limitations
on atenolol's use: . No p.o. or IV dose for HR < 55 or systolic BP < 100mmHg;
lowered dose of 50 mg po for heart rate 55-65. As a practitioner, one should
read the article in its entirety, paying attention to the exclusion criteria
and limitations on dosing before considering this therapy for any patient.
Only 60% of eligible patients tolerated full doses, and, as expected, hemodynamic
consequences were frequent, although, reportedly, no patient had a systolic
lower than 90 mmHg, or a HR < 40.
>From an economic standpoint, generic perioperative atenolol use appears
to be one of the most cost-effective therapies available to us. Mangano
computes the cost to be $500-$2500/.year of life saved. This compares well
to other standard low cost health care expenditures - eg. CABG for left
main disease costs $6000/year of life saved. An unreasonable expense is
usually considered >$50,000/year of life saved.
It is gratifying, for a change, to read something in the medical literature
that has such a great potential impact on patient care and that is so easily
implemented.
Reducing Cardiovascular Risk in Patients Undergoing Noncardiac
Surgery (editorial)
Eagle and Froelich NEJM 1996,
335:23: 1761.
[ no abstract available ]
The editorial makes some salient points and strikes some cautionary notes.
First, the authors note that there was a very low incidence of perioperative
cardiac events and deaths in Mangano's study, most likely as a result of
improved care in the intra- and postoperative period. This reinforces the
position that routine cardiac testing preoperatively to "get patients through
surgery" cannot be justified, especially for those in stable clinical condition.
Second, rather than limiting our in hospital treatment to administration
of perioperative beta blockers for patients at risk of coronary disease,
we should strive during the patients hospitalization to maximize patients'
treatment for cardiac disease by instituting long term therapy such as lipid
lowering drugs/dietary advice, smoking cessation programs, optimal anti-hypertensive
treatment, low dose aspirin and long term beta blocker therapy as indicated.
Finally, the editorial's authors advise that given the small study size
(200 patients) and the slight differences in patient might have combined
to affect the results. The implication is that a study with thousands of
patients is still necessary to confirm the results of Mangano et al. before
we give all patients with coronary risk factors, but no evident coronary
disease, perioperative beata blockers. However, they do endorse the use
of perioperative beta blocker therapy in patients with "clear or likely
evidence of coronary disease."
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