Elsevier

The Lancet

Volume 382, Issue 9905, 16–22 November 2013, Pages 1638-1645
The Lancet

Articles
Intra-aortic balloon counterpulsation in acute myocardial infarction complicated by cardiogenic shock (IABP-SHOCK II): final 12 month results of a randomised, open-label trial

https://doi.org/10.1016/S0140-6736(13)61783-3Get rights and content

Summary

Background

In current international guidelines the recommendation for intra-aortic balloon pump (IABP) use has been downgraded in cardiogenic shock complicating acute myocardial infarction on the basis of registry data. In the largest randomised trial (IABP-SHOCK II), IABP support did not reduce 30 day mortality compared with control. However, previous trials in cardiogenic shock showed a mortality benefit only at extended follow-up. The present analysis therefore reports 6 and 12 month results.

Methods

The IABP-SHOCK II trial was a randomised, open-label, multicentre trial. Patients with cardiogenic shock complicating acute myocardial infarction who were undergoing early revascularisation and optimum medical therapy were randomly assigned (1:1) to IABP versus control via a central web-based system. The primary efficacy endpoint was 30 day all-cause mortality, but 6 and 12 month follow-up was done in addition to quality-of-life assessment for all survivors with the Euroqol-5D questionnaire. A masked central committee adjudicated clinical outcomes. Patients and investigators were not masked to treatment allocation. Analysis was by intention to treat. This trial is registered at ClinicalTrials.gov, NCT00491036.

Findings

Between June 16, 2009, and March 3, 2012, 600 patients were assigned to IABP (n=301) or control (n=299). Of 595 patients completing 12 month follow-up, 155 (52%) of 299 patients in the IABP group and 152 (51%) of 296 patients in the control group had died (relative risk [RR] 1·01, 95% CI 0·86–1·18, p=0·91). There were no significant differences in reinfarction (RR 2·60, 95% CI 0·95–7·10, p=0·05), recurrent revascularisation (0·91, 0·58–1·41, p=0·77), or stroke (1·50, 0·25–8·84, p=1·00). For survivors, quality-of-life measures including mobility, self-care, usual activities, pain or discomfort, and anxiety or depression did not differ significantly between study groups.

Interpretation

In patients undergoing early revascularisation for myocardial infarction complicated by cardiogenic shock, IABP did not reduce 12 month all-cause mortality.

Funding

German Research Foundation; German Heart Research Foundation; German Cardiac Society; Arbeitsgemeinschaft Leitende Kardiologische Krankenhausärzte; University of Leipzig—Heart Centre; Maquet Cardiopulmonary; Teleflex Medical.

Introduction

Despite advances in treatment, mainly by early revascularisation, mortality in acute myocardial infarction complicated by cardiogenic shock remains high.1, 2, 3, 4 Intra-aortic balloon pump (IABP) counterpulsation has been the most widely used mechanical haemodynamic support device for nearly five decades.5 It improves diastolic blood pressure, thereby improving coronary perfusion, and by its afterload reduction properties myocardial oxygen consumption is reduced leading to an increase in cardiac output.6 However, on the basis of insufficient and conflicting evidence derived only from registry data,7 American and European guidelines recently downgraded IABP use for cardiogenic shock from a class I to a class IIa and IIb recommendation.8, 9, 10

Currently, only one sufficiently large randomised trial of intra-aortic counterpulsation in cardiogenic shock secondary to myocardial infarction (IABP-SHOCK II trial) has been done. Short-term follow-up data at 30 days from this trial showed no survival benefit with IABP support by comparison with control.11 However, long-term follow-up is necessary, especially since a previous trial in cardiogenic shock examining early revascularisation with no difference after 30 days showed a significant mortality benefit at extended follow-up.3, 12, 13 Therefore, the IABP-SHOCK II trial had prespecified intermediate 6 and 12 month follow-up for clinical outcome and quality of life.

Section snippets

Study design

The trial design of the prospective, randomised, open-label, controlled IABP-SHOCK II trial at 37 German centres, and the 30 day results including the primary endpoint, have been previously published.11, 14 The study was investigator-initiated and coordinated by the University of Leipzig—Heart Centre, Leipzig, Germany, and the Institut für Herzinfarktforschung, Ludwigshafen, Germany, acted as the clinical research organisation.

In brief, the main inclusion criterion was cardiogenic shock with

Results

Between June 16, 2009, and March 3, 2012, 600 patients of 790 initially screened were randomly assigned to IABP (n=301) or control (n=299). Figure 1 shows revascularisation, study protocol compliance, and follow-up. 12 month follow-up was complete in 595 (99%) patients. The baseline characteristics were well balanced between treatment groups.11 The median age was 70 years (IQR 58–77) and 413 (69%) were male. 270 (45%) underwent cardiopulmonary resuscitation before randomisation, 463 (77%) had

Discussion

In this prospective, randomised trial of patients with cardiogenic shock complicating acute myocardial infarction, IABP support did not increase 6 and 12 month survival compared with control, supporting the short-term 30 day follow-up data (panel). Despite early revascularisation and optimum medical therapy in both groups, mortality was still slightly higher than 50% at 1 year follow-up. Nevertheless, for survivors, the self-reported quality of life was moderate to good.

There are several

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