JAMA: Intra-aortic pump during PCI shows little difference
High-risk patients undergoing PCI who electively received an intra-aortic balloon pump (IABP) prior to the procedure did not experience a significantly lower overall rate of events such as MI, revascularization or death compared with those who did not receive a pump. While researchers don't advocate for prophylactic IABPs, they suggested that improved PCI techniques and drug therapies could have helped reduced the complication rate, according to the BCIS-1 study in the Aug. 25 issue of the Journal of the American Medical Association.

PCI in patients with impaired left ventricular function (ejection fraction less than 30) can be associated with a significant increased risk of illness or death, and these same patients with extensive coronary artery disease may have a diminished reserve to withstand the consequences of ischemia or arrhythmias that may occur during PCI.

"In these circumstances, vital hemodynamic support can be provided by an intra-aortic balloon pump, which simultaneously augments coronary blood flow and decreases myocardial oxygen demand," the authors wrote. "Observational studies have previously reported that elective IABP insertion may improve outcomes following high-risk PCI. To date, this assertion has not been tested in a randomized trial."

Divaka Perera, MD, of King's College London, and colleagues evaluated 301 patients in the BCIS-1 (Balloon Pump-Assisted Coronary Intervention Study) randomized trial from 17 tertiary referral cardiac centers in the U.K. between December 2005 and January 2009.

The primary outcome measure in the randomized controlled trial was major adverse cardiac and cardiovascular events (MACCE: defined as death, MI, cerebrovascular event or further revascularization at hospital discharge [up to 28 days]).

Interventional cardiologists placed a stent in 94 and 92 percent of lesions treated in the elective IABP and the no-planned IABP groups, respectively. Each group had a comparable success rate (93 percent) and a comparable number of stents deployed per patient (2.56 vs. 2.31, respectively), and 67 percent of stents were drug-eluting.

The primary endpoint of MACCE at hospital discharge occurred in 15.2 percent of the elective IABP group and 16 percent of the no-planned IABP group, and all-cause mortality at six months was 4.6 percent and 7.4 percent, respectively.

Predefined procedural complications occurred more often in the no-planned IABP group (10.7 percent) than in the group undergoing elective IABP insertion (1.3 percent). The most common component of these complications was prolonged procedural hypotension, which occurred in 13 patients in the group with no-planned IABP insertion and two patients in the group with elective IABP insertion.

Major or minor bleeding occurred in 19.2 percent of the elective IABP group and 11.3 percent of the no-planned IABP group. There was no difference between the groups in the incidence of major bleeding, but there was more minor bleeding in the elective IABP group (15.9 percent vs. 7.3 percent).

"The study did not demonstrate a difference in MACCE at hospital discharge and therefore does not support routine elective IABP insertion before high-risk PCI. However, 12 percent of patients who underwent PCI without elective IABP insertion required rescue IABP support, which highlights the importance of adopting a standby IABP strategy when undertaking high-risk PCI," the authors concluded.

Researchers noted an absolute 2.8 percent difference in mortality at six months favoring the elective IABP group, but it was not statistically significant and the study was not powered to detect a difference in mortality at six months.

They also found that patients receiving rescue IABP required longer IABP support and had a longer hospital stay than those who prophylactically received IABP support.

"In the absence of clear markers that would allow prospective identification of patients who will require rescue IABP insertion, a standby IABP approach is advisable when undertaking PCI in the presence of severe left ventricular impairment and extensive coronary disease," the authors wrote.

Researchers noted that their results contrast with data from previous registries and suggested the current patient population could have been more at risk.

They further suggested that the improved PCI techniques could have led to fewer complications in the no-IABP group. In addition, the centers in the trial were high-volume centers with experienced cardiologists performing the procedures, which could have reduced the complication rates in the non-elective pump group.

Asked via email how the Impella (Abiomed) cardiac assist device might have fared in this study, senior author Simon Redwood, MD, replied: "The Impella is a great support device, but should probably be reserved for higher risk patients (e.g., cardiogenic shock). I think this group of patients, as a routine, can safely undergo PCI (by selected operators!!) safely without hemodynamic support. Thus, if the Impella was used in the same group, I suspect the results would be negative."