2. INTRAAORTIC BALLOON SUPPORT
FOR MYOCARDIAL INFARCTION
WITH CARDIOGENIC SHOCK
Holger Thiele, Uwe Zeyer, Franz-Josef Neumann,
Miroslaw Ferenc, Hans-Georg Olbrich, Jörg Hausleiter
et al
The NEW ENGLAND JOURNAL of MEDICINE october 4,2012 vol.367 no.14
3. INTRODUCTION
IABP is a mechanical device that increases
myocardial oxygen perfusion while at the same time
increasing cardiac output
Increasing cardiac output increases coronary blood
flow and therefore myocardial oxygen delivery
4. Consists of a cylindrical polythene balloon that
sits in aorta, approximately 2cm from the left
subclavian artery and counter pulsates
Actively deflates in systole, increasing forward
blood flow by reducing after load. It actively
inflates in diastole, increasing blood flow to the
coronary arteries
These actions combine to decrease myocardial
oxygen demand and increase myocardial
oxygen supply
5. NEED OF THIS STUDY
A meta-analysis that included only cohort studies suggested
that the use of an IABP is associated with a reduction by 11%
Inconclusive evidence might be one explanation for the
in the risk of death.
current use of IABP in only 25 to 40% of patients with
In the recent shock, despite the recommendationsonly 45
cardiogenic (IABP-SHOCK) trial, which involved in the
guidelines
patients, no significant difference was observed with
respect to the (APACHE II) score for severity of illness
Thebetween patientstrial was designed to test the hypothesis that
IABP-SHOCK II assigned to IABP and those assigned to a
IABP as compared that received available care, although serial
control group with the best standard medical therapy alone,
results in natriuretic peptide levels were significantly reduced in
brain a reduction in mortality among patients with acute
myocardial infarction complicated by cardiogenic shock for whom
the balloon-pump group.
early revascularization is planned
6. METHODS
TYPE OF STUDY
Randomized, prospective, open-label, multicenter trial,
Randomization
Internet-based program, with stratification
according to center.
PERIOD-june16th,2009-march3,2012
7. ELIGIBLE CRITERIA
Acute myocardial infarction (with or without ST segment elevation) complicated by
cardiogenic shock and if early revascularization (by means of PCI or CABG) was
planned.
CARDIOGENIC SHOCK
Systolic blood pressure <90 mm hg for more than 30 minutes
Catecholamine's to maintain a systolic pressure >90 mm hg
Signs of pulmonary congestion and
Impaired end- organ perfusion.
Altered mental status
Cold, Clammy skin and extremities
Oliguria with urine output of less than 30 ml per hour
Serum lactate level higher than 2.0 mmol per liter
8. EXCLUSION CRITERIA
Resuscitation for more than 30 minutes
Had no intrinsic heart action were in a coma with fixed dilatation of
pupils that was not induced by drugs
Had a mechanical cause of cardiogenic shock (e. g Ventricular
septal defect or papillary muscle rupture)
Had onset of shock more than 12 hours before screening
Older than 90 years of age
Shock as a result of a condition other than acute myocardial
infarction
Had severe concomitant disease associated with a life expectancy
of less than 6 months
9. Had a massive pulmonary embolism
Severe peripheral arterial disease precluding insertion
of an IABP or aortic regurgitation greater than grade II
in severity
14. DISCUSSION
No immediate improvement in blood pressure or
heart rate between two groups.
Although positive effect of IABP on multiorgan
dysfunction at day 2 and 3, as assessed with the use
of the SAPS II, this effect was not evident at day 4.
No significant effects on CRP level or serum lactate
level, which were assessed as measures of
inflammation and tissue oxygenation.
15. Studies showed IABP results in a hemodynamic benefit as a
result of afterload reduction and diastolic augmentation with
improvement in coronary perfusion. However, the effects on
cardiac output are modest and might not be sufficient to
reduce mortality.
In a recent, small, randomized trial, there were no significant
differences in cardiac power output, left ventricular stroke-
work index, or systemic vascular resistance between
patients assigned to IABP and those assigned to a control
group.
16. Use of IABP before coronary revascularization may make the
revascularization procedure safer by improving left ventricular
unloading.
However, in the current trial, there was no mortality benefit
in the subgroup of patients in whom the IABP was inserted
before the start of revascularization, as compared with those
in whom it was inserted after revascularization.
In another recent randomized trial involving patients with large
anterior infarctions but without cardiogenic shock, insertion of
a balloon pump before PCI, as compared with control
treatment did not reduce the infarct size.
17. LIMITATIONS
① Blinding was not possible because of the nature of the intervention..
② Hemodynamic measurements or assess laboratory inflammatory markers
other than blood pressure, heart rate, and c-reactive protein levels, not
done
③ The slightly lower mortality in trial — approximately 40%, as compared
with 42 to 48% in other randomized trials and registries — might suggest
that trial included a higher percentage of patients with mild or moderately
severe cardiogenic shock, a factor that could preclude generalization of the
results to patients with the most severe forms of cardiogenic shock.
18. ④ The negative overall result, cannot definitively rule out a type
II error;
⑤ No information about longer-term outcomes. To minimize bias,
use of a central randomization system, and the members of
the clinical events committee were unaware of the group
assignments.
19. CONCLUSION
CONTROLLED TRIAL OF INTRAAORTIC BALLOON PUMP
S U P P O R T I N PAT I E N T S W I T H C A R D I O G E N I C S H O C K
C O M P L I C AT I N G M Y O C A R D I A L I N F A R C T I O N F O R W H O M
E A R LY R E VA S C U L A R I Z AT I O N A S C O M PA R E D W I T H
C O N V E N T I O N A L T H E R A P Y, D I D N O T R E D U C E 3 0 - D AY
M O R TA L I T Y.
To minimize bias, use of a central randomization system, and the members of the clinical events committee were unaware of the group assignments.4) however, the minor absolute difference in mortality, together with the lack of benefit with respect to second- ary end points, makes any clinically meaningful positive effect unlikely.
