BCIS-1 Trial: "Bailout" Intra-Aortic Balloon Pump Beats Elective Use in Low EF/High-Risk Patients

Shelley Wood

September 30, 2009

September 30, 2009 (San Francisco, California) Elective use of an intra-aortic balloon pump (IABP) in patients with low ejection fraction undergoing high-risk angioplasty procedures is no better than "bailout" IABP use in preventing major cardiac and cerebrovascular events (MACCE), results from the Balloon-Pump Assisted Coronary Intervention Study (BCIS)-1 trial show.

Presenting the results last week at the TCT 2009 meeting, Dr Simon Redwood (King's College, London, UK) emphasized that while the trial clearly supports the important role of IABPs in hypotensive patients, the results should serve as a wake-up call to physicians already convinced that IABPs are necessary in all patients with low EF facing complex procedures. For example, benchmark registry data from 2001 suggests that elective balloon-pump use during high-risk angioplasty accounts for roughly 20% of IABP use in the US, Redwood commented during a press conference.

"When we were designing the trial and trying to recruit centers, the centers that refused said they already knew the answer, and roughly half of those said all of these patients need balloon pumps, and the other half said they didn't," Redwood told heartwire . "The message is not that we do not need balloon pumps. The message is that we probably do not need them electively in all patients, but we need to have them available for bailout situations very early."

As Redwood explained, IABP works by increasing coronary flow and reducing oxygen demand of the heart. As such, they've been shown to be beneficial in situations like cardiogenic shock, where there is low blood pressure and poor heart function. While a number of small, mostly registry studies have suggested IABPs may also be useful in high-risk angioplasty in the setting of poor left ventricular function, no properly designed, randomized controlled trials have ever been performed to specifically address this issue, he said.

Ballooning Interest

For the BCIS-1 trial, Redwood and colleagues randomized 300 patients to either elective IABP use or "no planned" IABP use, with bailout IABP permitted. To be enrolled in the study, all patients had to have an ejection fraction of <30% and extensive myocardium at risk. The latter was defined by either a coronary occlusion of a vessel supplying at least 40% of the myocardium or by a myocardial jeopardy score >8.The primary end point for the study was MACCE at the time of hospital discharge, with a cutoff of 28 days.

According to Redwood, MACCE rates as well as individual components of the end point were not statistically different between the two groups. Major secondary outcomes, such as mortality, complications, and length of stay, were also no different between the elective and no-planned IABP groups, with the exception of procedural complications (lower in the elective group), and minor bleeds (higher in the elective group).

Investigators also looked at the 18 patients (12%) who ended up receiving an IABP in the no-planned group; hypotension was the primary reason for IABP bailout, Redwood noted. Mean EF in these patients was 24%, and mean jeopardy score was 11.2, with 13 out of 18 patients having the maximum jeopardy score of 12 (72% of bailout patients). By way of comparison, just 45% of patients in the overall trial had a jeopardy score of 12. The 12% bailout rate supports "the important role of provisional IABP use," Redwood observed.

He also underscored the "acceptable" mortality among patients in the trial, despite their low EF and high jeopardy scores: just 1.3% in hospital and 6% at three months. Of note, while not statistically different, mortality curves out to six months numerically favored the elective-IABP group, Redwood noted.

IABP Support Right for the Right Patient

Commenting on the study, Dr Roxana Mehran (Columbia University, New York, NY) highlighted the mortality curves. The trial wasn't powered for mortality, she acknowledged, "but the fact is, the elective IABP is in the lower curve, and there's some separation of the curves as you go down the line beyond 30 days. That tells me that there is something that needs to be verified in a larger trial" and that "having those supportive devices available for the right patient [is] extremely important."

Redwood also emphasized that the jeopardy score speaks to the myocardial "territory" at risk but doesn't take into account lesion morphology or other factors that drive up procedural risk. "The point is, if you are going to deal with a very complex lesion, one that's calcified, that’s left main, etc, that perhaps you'd have a much lower threshold for using a balloon pump." The trial did not specifically take these issues into account, he noted, and it is hoped that future research will identify better ways for identifying patients who would benefit from elective IABP support.

Still, the trial does address the belief, held by some, that low ejection fraction per se means IABP support is beneficial during high-risk procedures. According to Dr Divaka Perera (St Thomas' Hospital, London, UK), a coinvestigator for BCIS-1, this trial offers some clear answers. "There are a lot of people who use [IABP] at the moment--the kinds of interventionalists who treat this kind of complex disease. They swear by it, so for them, I think this could have a major impact on practice."