Physicians and medical boards may have to reconsider decades of cardiogenic shock treatment after the highly anticipated IABP-Shock study found no significant benefit in using intra-aortic balloon pump therapy in heart attack patients.
Intra-aortic balloons are among the earliest medical devices, 1st introduced in 1968, and treatment with the device inserted in the aorta is currently the "most widely used mechanical support device in cardiogenic shock," according to a report released from the 2012 European Society of Cardiology Congress in Munich, Germany.
Despite wide use and clinical acceptance, the procedure failed to produce only minimal clinical benefit in the largest trial ever performed in cardiogenic shock, the 600-patient IABP-Shock study.
Researchers looked at 30-day mortality rates in patients who received IABP therapy and compared outcomes to a group of patients who received standard care alone.
"The IABP showed no improvement in blood pressure, no reduction in treatment time in the intensive care unit, no decrease in the duration or dose of drugs prescribed, and no improvement in organ perfusion," according to the ESC report. "On the other hand, the trial results showed that the IABP did not induce complications, and was shown to be a safe device."
Trial sponsor Maquet Cardiovascular tried to look on the brighter side of the study results. The study did find a mild 30-day benefit among IABP patients, even though it did not meet the 12% improvement mark researchers were aiming for, the company noted in a press release.
"The results of the SHOCK II trial demonstrated unparalleled safety with IABC therapy in this patient population, and I believe it would be premature, without further exploration of the data, to determine which patients are best served with IABC therapy," Beth Israel Medical Center cardiology chief Dr. Marc Cohen said in Maquet’s press release. "Previous clinical trials in other patient populations, including those undergoing high-risk percutaneous coronary intervention [PCI], have shown that the benefits of IABC therapy can be seen beyond 30 days. It is important that we wait and assess the six-month and 12-month mortality data from IABP-SHOCK II before making definitive conclusions about the use of IABC therapy in cardiogenic shock patients."
Although the trial didn’t achieve a statistically significant difference in 30-day mortality between the IABP and control arms, a difference was beginning to emerge at the 20-30 day mark, Maquet noted. After 30 days the mortality rate in the IABP arm was 39.7%, compared with 41.3% in the control group.
Despite Maquet’s perspective that the results aren’t substantial enough to change clinical practice, some ESC attendees predicted that the reaction to the Shock study could be pervasive.
"I think the importance of this trial … is incredible," University of Pennsylvania cardiovascular medicine associate chief Dr. Mariell Jessup told Medpage Today during the conference. "I think this has the potential for changing guidelines and changing clinical practice."