IABP SHOCK II trial: Randomized comparison of intraaortic balloon counterpulsation versus optimal medical therapy in addition to early revascularization in acute myocardial infarction complicated by cardiogenic shock Discussant Uta C. Hoppe, MD, FESC Dep. of Internal Medicine II Paracelsus University Salzburg Austria
No disclosures related to the trial
Current Recommendations STEMI complicated by Cardiogenic Shock ACC/AHA STEMI-Guidelines, Circulation 2009;110:588-636 Class I 1. Intra-aortic balloon counterpulsation is recommended for STEMI patients when cardiogenic shock is not quickly reversed with pharmacological therapy. The IABP is a stabilizing measure for angiography and prompt revascularization. (Level of Evidence: B) ESC STEMI-Guidelines, Eur Heart J 2008;29:2909 Treatment of shock (Killip class IV) Intra-aortic balloon pump Class I Level of Evidence C NSTEMI complicated by Cardiogenic Shock ACC/AHA UA/NSTEMI-Guidelines, Circulation 2007;116;e148 The placement of an IABP could be useful in patients. with hemodynamic instability until coronary angiography and revascularization can be completed.
Guideline recommendations based on Hemodynamic considerations - IABP improves peak diastolic pressure and coronary blood flow - IABP reduces endsystolic pressure, afterload and myocardial oxygen consumption TACTICS trial - 57 patients - MI complicated by sustained hypotension/ cardiogenic shock - randomized to fibrinolysis + IABP or fibrinolysis alone Killip class III or IV trend toward greater benefit from IABP (6-month mortality 39% vs. 80%; P = 0.05) Ohman et al. J Thromb Thrombolysis 2005;19:33
30-day Mortality (%) Thrombolytic therapy vs. primary angioplasty +/- IABP in MI with cardiogenic shock In-hospital Mortality (%) GUSTO 1 subgroup analysis National Registry of Myocardial Infarction 2 64 62 66.9 47 44 48.7 42 46.5 Anderson et al. JACC 1997;30:708 Barron et al. Am Heart J 2001;141:933
IABP SHOCK II: Selection of Patients First large randomized trial (600 pts) in MI with CS +/- IABP with robust clinical endpoint IABP Control STEMI/LBBB 66.7% 71.1% NSTEMI 32.0% 27.2% Patients were in cardiogenic shock Signs of impaired organ perfusion - Altered mental status 71.7% 77.6% - Cold, clammy skin and extremities 85.7% 81.9% - Oliguria 30.0% 33.1% - Serum lactate >2.0 mmol/l 75.3% 73.2% Primary PCI 95.3% 96.3% Stenting 90.7% 89.0%
IABP SHOCK II failed to reach 1 ary /2 ary endpoints IABP had no impact on - 30-day mortality (39.7% IABP vs. 41.3% control, p=0.92) independent of STEMI/NSTEMI. - renal function, serum lactate (marker for microcirculation), and CRP increase (parameter of inflammatory reactions). Importantly, IABP therapy was safe.
Limitations & open Questions - Congratulations on a well designed, randomized study in the setting of cardiogenic shock. - Cross-over of 10% to IABP therapy might have influenced the results. - More frequent use of LAVDs in control patients (7.4% vs. 3.7%) might have influenced the results. Further analysis of interest: - Timing of IABP implantation - Time until reperfusion - Mortality after 6 and 12 months (predefined secondary endpoint) (given that the SHOCK trial was also negative at 30 days and only became positive after 6 months)
Implications IABP in myocardial infarction complicated by cardiogenic shock - Improved hemodynamic status alone no surrogate marker for survival - Outcome after PCI/ stenting does not seem to rely on coronary perfusion pressure - Remaining high mortality in cardiogenic shock unlikely caused by an underuse of IABP therapy - IABP not for allcomers with MI and CS - Guidelines might need to be reconsidered, particularly, if 6- and 12-month data will confirm the neutral effect of IABP treatment