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AMSTERDAM -- One year out, intra-aortic balloon pump (IABP) support still did not reduce mortality among patients with acute myocardial infarction complicated by cardiogenic shock, extended follow-up of the IABP-SHOCK II trial showed.

Confirming the primary 30-day results, the percentage of patients who had died through 1 year was no different between the IABP and control groups (52% versus 51%; RR 1.01, 95% CI 0.86-1.18), according to Holger Thiele, MD, of the University of Leipzig-Heart Center in Germany.

Patients who survived had moderate-to-good quality of life, but there was no difference between the two study arms, he reported at the European Society of Cardiology meeting here. The results were published simultaneously online in .

"Unfortunately the intra-aortic balloon pump that has been used for so many decades does not alter the natural course and it does not reduce mortality," Jan Piek, MD, PhD, of the Academic Medical Center in Amsterdam, commented after Thiele's presentation. "So I think in this respect that this trial is endorsing the recent downgrading of the recommendations from class I to class II."

Although IABP support has been used for several decades for patients with acute myocardial infarction (MI) complicated by cardiogenic shock, registry data suggesting that it does not work prompted the downgrading of recommendations in both and guidelines from class I to class IIb and IIa, respectively.

The IABP-SHOCK II trial -- conducted at 37 German centers -- explored the usefulness of IABP support in 600 patients (median age 70) with acute MI complicated by cardiogenic shock, defined as the presence of systemic hypotension, pulmonary congestion, and signs of impaired organ perfusion. All of the patients were on optimal medical therapy and were scheduled to undergo early revascularization, preferably with percutaneous coronary intervention.

The median duration of IABP support was 3 days in the trial, which failed to show a significant difference between the IABP and control groups in all-cause mortality at 30 days.

The extended follow-up presented by Thiele confirmed the lack of a mortality benefit and failed to show differences on any other endpoint, including reinfarction (9% versus 3%; RR 2.60, 95% CI 0.95-7.10), recurrent revascularization (20% versus 22%; RR 0.91, 95% CI 0.58-1.41), or stroke (2% versus 1%; RR 1.50, 95% CI 0.25-8.84).

In a multivariate analysis, the researchers identified some characteristics that predicted mortality, including older age, history of stroke, baseline serum lactate, creatinine concentration, oliguria, altered mental status, pH lower than 7.36, and left bundle branch block at admission.

That information possibly could be used to assess the mortality risk in these patients, Thiele said.

Although there have been some reductions in the mortality rates among patients with acute MI and cardiogenic shock in recent years, they remain high, meaning that researchers need to continue looking for ways to improve outcomes, Piek said.

He noted that Thiele is currently participating in the , which is comparing PCI of the culprit lesion only (with staged revascularization of other arteries) with immediate PCI of multiple vessels.

Another potential option for improving outcomes, he said, is the use of more powerful assist devices.

"One of the crucial factors is that you would like to reduce inotropic agent and the vasodilator dose because that's a part of the so-called vicious circle in cardiogenic shock," Piek said. "And maybe these more potent assist devices may be helpful in that respect."

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