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Saying good-bye to the IABP? Farewell, old friendAug 27, 2012 06:40 EDT
Dr Holger Theile from the University of Leipzig presented on behalf of the IAPB-SHOCK II trial this morning at the ESC 2012 meeting in Munich. During the presentation, it dawned on me just how much the treatment milieu for ACS has changed in our part of the world. "So did PCI kill the balloon pump?" asked one of the chairpersons at today's press conference. That question mirrored my thoughts exactly.
The randomized controlled trial of 600 patients studied the role of an IABP in cardiogenic shock, defined as a systolic blood pressure lower than 90 mm systolic or requiring inotropic support. Patients either received "optimal medical therapy" or a device. Surprisingly at first, there was no reduction in 30-day mortality. The only comfort in the results was the lack of statistically significant adverse effects of placing a balloon into the descending aorta to improve diastolic flow to the coronaries.
Prior to this presentation, the mere suggestion an IABP would be relegated to the boneyard where other less worthy devices sit languishing was incendiary. I was an angiographer who performed coronary catheterization "without a net" for around 14 years, where neither PCI nor surgical backup were available. We had a busy lab where patients in cardiogenic shock would limp into home plate cold and wet, death swirling about them. We would rush those patients to the cath lab, gain vascular access, and "pump them" until we could define their coronaries. Before we could transport them to a PCI-capable center, we stabilized most of them as best we could with pressors, pacers, and prayer. Sometimes we still needed extra help, and for that, we turned to our friend the balloon pump. Although we didn't require an IABP often, the presence of the IABP waiting patiently in the corner of our cath lab was a comfort. We required it to be available before proceeding with any angiography and rarely were forced to cancel or delay cases if the transport helicopter took ours because it was not equipped with its own. Now that PCI has been diffused throughout many communities in America, including places that do not have on-site surgical backup, the need for mechanical support is waning.
I'm not an interventionalist, but I've assisted with many PCI procedures in my career as an angiographer. There are still some patients who will require IABP support. Instead of trying ride out and wire the vessel of a fibrillating patient like a bucking bronco between V-fib arrests and shocks, a quick IABP insertion to stabilize the hemodynamics and perhaps quiet an electrical storm is sometimes a welcome respite. It might make for a shorter door-to-balloon time in the long run for some patients as well. Surgeons will not be so quick to ditch the IABP, as some patients will continue to require post-CABG support. There are still a few labs in the US that do not have PCI capability but have a cardiologist angiographer who might still save a dying patient presenting deeply in cardiogenic shock. The Impella device, though, a smaller, less cumbersome cousin of the IABP, is up and coming in some communities and may all but finish the balloon-pump era as we know it.
According to heartwire reporter Michael O'Riordan's piece in 2008 at the time of death of the IABP inventor, Dr Adrian Kantrowitz, over three million patients had been mechanically supported with the device. At the time of its invention in the 1960s, almost 80% of patients presenting in cardiogenic shock had no other recourse but a fatal outcome, as therapies were limited. The first successful implant occurred in 1967 in a 48-year-old woman who was successfully discharged. Our gratitude should be extended to Dr Kantrowitz (the first US surgeon to perform a heart transplant) and his brother Arthur, an engineer who was instrumental in the IAPB and the LVAD, among other devices.
I have mostly fond memories of my infrequent but necessary dalliances with the balloon pump. I guess this is farewell, old friend, at least for me.