|Pre-Op Risk Assessment - pg 2
Treatment - BB, Statins, Nitrates, ACE-I, CCB
During the perioperative period, there is a catecholamine surge, resulting in an increased heart rate and
myocardial contractility and subsequent increased myocardial oxygen consumption. The main rationale
for perioperative b-blocker use is to decrease myocardial oxygen consumption by reducing heart rate,
resulting in a lengthening of the diastolic filling period, and decreased myocardial contractility. Additional
cardioprotective factors are redistribution of coronary blood flow to the subendocardium, plaque
stabilization, and an increase in the threshold for ventricular fibrillation
-The most recent meta-analysis concluded that b-blockers result in 16 fewer non-fatal MIs per 1000 patients
treated, but at the expense of three non-fatal disabling strokes and (possibly) three fatal cardiac or non-cardiac
-However, it should be acknowledged that the recent POISE trial had the greatest weight in all of the above
analyses. Indeed, 80% of the deaths, MIs, and strokes in this meta-analysis are derived from POISE. That
different effect of treatment seems to result from the high mortality in POISE patients who are given b-blockers
(3.1% vs. 1.9% in non-POISE trials). Hypotension can be related to the use of a high dose of metoprolol
(200mg) without dose titration in POISE.
-Extensive ischaemia by stress testing are at particularly high risk of perioperative cardiac complications,
despite perioperative b-blockers.
-Low-risk patients: perioperative b-blockade does not decrease the risk of cardiac complications in patients
without clinical risk factors. The possibility of a harmful effect on mortality has been suggested by a
retrospective cohort and the POISE trial.
-Atherosclerosis: Bradycardia and hypotension may be harmful in patients with atherosclerosis, and possibly
favour stroke. This does not justify exposing low-risk patients to potential side effects in the absence of proven
-Intermediate-risk patients, i.e. those with one or two clinical risk factors. Results of the DECREASE IV trial
suggest that b-blockers should also be used in patients undergoing intermediate-risk surgery.88 Patients
randomized to bisoprolol (n ¼ 533) had a lower incidence of the primary efficacy endpoint than those
randomized to bisoprolol-control therapy (2.1% vs. 6.0% events, HR 0.34, 95% CI 0.17–0.67).
-Withdrawal: An increased mortality following pre-operative b-blocker withdrawal has been reported in
observational studies. b-Blockers should be continued when prescribed for IHD or arrhythmias.
-CHF: b-Blockers should not be withdrawn in patients treated for stable heart failure due to LV systolic
dysfunction. In decompensated heart failure, b-blocker therapy may need to be reduced, or temporarily
omitted. If possible, non-cardiac surgery should be deferred so that it can be performed under optimal medical
therapy in a stable condition.
-Contra-indications to b-blockers (asthma, severe conduction disorders, symptomatic bradycardia, and
symptomatic hypotension) should be respected.
-Claudication: b-Blockers are not contra-indicated in patients with intermittent claudication, as in randomized
trials, worsening of symptoms has not been shown to occur more frequently.
-COPD: a recent study showed that cardioselective b-blockers were associated with reduced mortality in
patients with chronic obstructive pulmonary disease (COPD) undergoing vascular surgery.
In the absence of contra-indications, b-blocker dose should be titrated to achieve a heart rate between
60 and 70 beats/min. b1-Selective blockers without intrinsic sympathomimetic activity are favoured.
The dose of b-blockers should be titrated,
which requires that treatment be initiated
optimally between 30 days and at least 1 week
before surgery. It is recommended that
treatment start with a daily dose of 2.5 mg of
bisoprolol or 50 mg of metoprolol succinate to
achieve a resting heart rate of between 60 and
70 beats/min with systolic blood pressure >100
for secondary prevention, independently of noncardiac surgery.
Statins also induce coronary plaque stabilization by decreasing lipid oxidation, inflammation, matrix -A
meta-analysis of 223 010 patients from12 retrospective and three prospective trials showed that statins
reduced mortality significantly by 44% in non-cardiac surgery and by 59% in vascular surgery.
-The most recent randomized controlled trial was the DECREASE III study. A total of 497 vascular surgery
patients were allocated to either fluvastatin ER 80 mg or placebo, starting 37 days prior to surgery. The
incidence of MI in patients allocated to fluvastatin or placebo was 10.8% vs. 19.0%, respectively. The incidence
of cardiac death or MI in the two study groups was 4.8% vs. 10.2%.
-No studies have been published that support the concern of increased rhabdomyolysis, except for some case
rhabdomyolysis, significantly higher CK level, or increased incidence of myopathy were observed in statin users
-Statins with a long half-life or ER formulations such as rosuvastatin, atorvastatin& fluvastatin ER are
recommended, to bridge the period immediately after surgery when oral intake is not feasible.
One small but controlled study has demonstrated
decreased perioperative MI in patients with stable
angina given i.v. nitroglycerin during non-cardiac
surgery. However, no effect was observed on the
incidence of MI or cardiac death.
ACE-I preserve organ function. This effect is
interference with atherogenesis.
The QUO VADIS study compared the effect of the
ACE inhibitors quinapril with that of placebo in
patients undergoing cardiac surgery. Quinapril
treatment was started 4 weeks before elective sx
and was continued up to 1 year after surgery.
Post-operative cardiovascular events were
significantly reduced (HR 0.23, 95% CI 0.06–0.87)
in patients treated with quinapril. The beneficial
effect could be the result of the post-op trt.
Risk of severe hypoT under anaesthesia
ACE inhibitor withdrawal may be considered 24 h
before surgery when they are prescribed for HTN.
It is necessary to distinguish between
dihydropyridines that do not act directly on HR
and diltiazem or verapamil that lower HR.
A meta-analysis showed only statistical
significance when endpoints of death and/or MI
Studies favored Diltiazem.Nifedipine/Verapamil
associated with increased mortality