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Comparison of Prophylactic Agents


There are no trials which compare the efficacy of any of the prophylactic modalities. Tables 2 and 3 compare results obtained from the series of meta-analyses. The efficacy of the sympatholytic agents (beta-blockers, alpha-2 agonists and thoracic epidurals) in preventing myocardial infarction and death are remarkably similar.

The side effect profiles are seen in Table 3. Significant hypotension is seen with epidural use but is associated with less transfusion requirements. Similarly, low dose aspirin therapy in over 6000 patients did not cause a significant rise in the need for transfusion. Bradycardia and hypotension requiring treatment is seen with beta blockers. In the POISE trial, hypotension was linked to more deaths and strokes. Although there is a suggestion from this data that congestive heart failure is most frequent with beta-blockers, the majority of the data comes from studies where metoprolol was administered acutely in the postoperative period.

Table 2: Comparison of the efficacy of single agent medical therapies.

Death (Incidence)

Myocardial Infarction (Incidence)

Study

Trials

Treatment

Control

Effect
(95% CI)*

Treatment

Control

Effect
(95% CI)*

β-blockers

Ban galore et al

10

160/5647

127/5467

OR 1.2(.95-1.51)

179/6040

268 /5775

RR 0.65
(.54-0.79)

Calcium channel blockers

Wijeysundera et al.(39)

7

5/358

12/334

RR 0.40 (.14-1.16)

0/252

5/234

RR 0.25
(.05-1.12)

α-2 agonists

Wijeysundera et al.(40) (updated Wallace et al.)(41)

9

30/1514

45/1337

RR 0.61 (.39-0.96)

83/1486

93/1313

RR 0.84
(.64-1.12)

Nitrates

Bender et al.

2

0/31

0/29

NA

0/53

1/52

OR 0.33
(.01-8.63)

Thoracic Epidural

Beattie et al

9

29/937

41/933

RR 0.69 (.42-1.12)

29/815

52/820

RR 0.53
(.35-0.88)

Low dose aspirin

Unpublished

4

547/12575

577/12552

RR 0.94 (.84-1.05)

93/10529

114/10511

RR 0.79
(.60-1.05)

Table 3: Side effect profiles of the proposed perioperative risk reduction therapies.

Hypotension OR (95% CI)

Bradycardia OR (95% CI)

Congestive Heart Failure OR (95% CI)

Bronchospasm OR (95% CI)

Bleeding Complications Requiring Transfusion OR (95% CI)

Beta-Blocker

1.62
(111.44-1.82)

2.74
(2.29-3.29)

1.20
(0.95-1.52)

0.98
(0.5-1.7)

NA

Alpha-2 Agonist

1.04
(0.9-1.21)

1.05
(.82-1.36)

0.82
(0.5-1.4)

NA

NA

Calcium Channel Blocker

3.32
(0.7-15.6)

1.05
(0.2-5.3)

0.6
(0.01-4.8)

NA

BLOOD LOSS -47 ML P=0.1

Nitrates

0.84
(0.25-2.3)

NA

NA

NA

NA

Aspirin

NA

NA

NA

NA

1.48
(0.85-2.57)

Thoracic Epidural

7.0
(4.0-10.0)

NA

0.5
(0.01-3.0)

na

0.43
(0.28-0.66)



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