Conversations in Cardiology – Does Every Primary PCI Lab Need an Impella* (or Its Equivalent)?

In this “Conversation in Cardiology”, Dr. Ted Feldman from Evanston Hospital, Evanston, Illinois, asks, “Is the availability of Impella a requirement for every STEMI [ST-elevation myocardial infarction] program (even in lower volume programs or in smaller institutions)?”

This seemingly simple question was discussed among our expert cath lab colleagues. It should be no surprise that the answers were varied and covered some very critical aspects of small percutaneous coronary intervention (PCI) programs, transfer of the critically ill, and the data supporting (or not supporting) the use of higher levels of hemodynamic support for the STEMI patient in shock. Here’s what they said. 

Mort Kern, Long Beach, Calif.:  Ted, great question. My short view (and as I learned from my colleagues, a minority report) is “yes”, since you won’t know which patient will need hemodynamic support or go into shock. I believe the hemodynamic data favors Impella over an intra-aortic balloon pump (IABP) and although the clinical outcomes of hemodynamic support are not different, I believe more support is better than less. Regarding requirement for Impella, I’d say if the lab was fully staffed and comfortable with TandemHeart (CardiacAssist) or cardiopulmonary support (CPS) (surgically), one could forgo the Impella, but these seem a cumbersome and much more involved way to support the patient. For the record, we are a low-volume center at the VA-Long Beach (100-200 PCI/year) and infrequently use Impella (2-3/year), but when we need it, we really need it. Also, we are a PCI program with off-site surgical backup, so this aspect of our program makes availability of Impella of added importance.

Jeffrey Moses, New York City, NY.: I don’t agree, but with a different rationale. An organized transfer process should be in place for availability. I think extracorporeal membrane oxygenation (ECMO) is more a priority for a total crash. As for randomized data…good luck [with that]. We can’t use that [randomized data as it is now (–MK)] as a standard since randomized clinical trials (RCTs) are very difficult to complete. Sometimes we don’t have level “A” evidence, but need to take the best data available to make decisions.  

Mort Kern, Long Beach, Calif.:  SHOCK II said IABP was not very effective. But, like Jeff Moses, I don’t think we must wait for randomized data to support the shock patient even with a mildly ineffective support device like IABP. The infrequency and complexity of trying to sort these patients into randomized trials will be near impossible.  

Bonnie Weiner, Worchester, Mass.:  I agree with “no” [to requiring Impella]. The transfer process is key. My concerns with this [Impella] being used infrequently at small programs are several. One concern is, should these programs exist at all? Most are within “spitting distance” of a full-service, experienced facility, and transfer or “level 1” myocardial infarction (MI) centers would likely provide better care. It isn’t just about the PCI, it is about the entire care environment. Staff both in the lab and coronary care unit (CCU) will not be experienced in taking care of these patients, transfer with an Impella in place is more complicated, and all of the support options available for appropriate patients will not always be considered.

Ajay Kirtane, New York City, NY.: Personally, I don’t think it is an absolute requirement, but when we do quality assurance (QA) reviews for outside hospitals (not part of our network) that do not have any form of hemodynamic support other than IABP, we do see acute MI/shock cases that are either too high risk to survive PCI or are transferred out from these hospitals to tertiary centers. In many of these cases, the delays in transfer, etc., are so great that the patient literally has no chance of making it and the outcomes are universally dismal in these cases.

In most of our reviews of these cases, we end up concluding that having some form of advanced hemodynamic support might have allowed these sites to either reperfuse more safely on-site and/or help to facilitate the safer transfer of these patients. In my mind, Impella is easier to use for this purpose, but we do work with some sites that are very facile in rapid initiation of portable ECMO systems, too.

Jim Blankenship, Hershey, Penn.: Many small programs do 100-200 PCIs/year. It is unlikely that their doctors or staff will be facile with Impella or ECMO. Furthermore, patients who are sick enough to need Impella or ECMO should probably be cared for at larger institutions. Transfer to a larger institution AFTER initiation of Impella or ECMO has its own set of problems, including displacement of the Impella.  When a shock patient rolls into the emergency department (ED) at a low-volume center, it often takes half an hour for the cath team to assemble. If that same half hour can be used to transfer the patient while a team assembles at a larger, full-service institution, I believe that transfer would be preferable. This requires efficient transfer systems, which small programs should have in place anyway. A low-volume, small program that held onto critically ill patients for non-patient care reasons would not be serving their patients well.

Jeffrey Moses, New York City, NY.: It would be great if transfers were that swift. But, in the balance, as much as I like Impella, I think training a small-volume staff on the Cardiohelp (Maquet) is a more robust solution with simpler implant and less issues of displacement.

Steve Bailey, San Antonio, Tex.: The plan for care and support is the critical issue, not simply the device. The impact for many shock patients extends beyond the cath lab procedure. Many small-volume centers may not have CCU staff that is experienced in Impella/TandemHeart management or ECMO, which may also be required. Many of these patients may also be candidates [with return of spontaneous circulation (ROSC)] for hypothermic protocols.  

This is the patient population where rapid transfer to a center with devices and experience should be accomplished. Some regional programs, such as ours, are developing “Shock Centers” much like trauma centers so that this is part of the early triage strategy to provide dedicated access for these patients.

David Kandzari, Atlanta, Ga.: I also do not believe [Impella] should be a requirement for STEMI programs. But rather than worry about which type of device, the greatest barrier to the [care of the] shock patient remains whether the interventionalist will even treat the patient. If only one technology was available, ECMO — despite its limitations — may also represent in the short term, a more complete modality for support that would cover other indications than acute MI shock. But it is labor-intensive (perfusionists, interventionalists). Some programs are exploring the concept of a travel team to fly to centers, cannulate on site, and bring the patient to a tertiary center. Overall, the controversy speaks to having effective systems in place for such instances. 

[To the debate of randomized trial evidence and support devices regarding Impella, please see the editorial debate between Rick Page (who chaired one of our FDA Panel sessions related to Impella and other devices) and a group of Yale cardiologists, recently published in JAMA Cardiology.^1,2]

Gurpreet S. Sandhu, Rochester, Minn.: I don’t think anyone can or should mandate one commercial device over another for a STEMI program. Our group has Impella, ECMO, IABP, and TandemHeart available. When you truly need support in an emergency, TandemHeart is too cumbersome and IABP barely helps. Percutaneous ECMO is my first choice in a younger/viable patient, but requires dedicated perfusionist support that may not be available at a site without surgery. However, these patients would transfer to a higher level of care and ECMO would provide more durable cardiopulmonary support during transfer. Impella is also good choice for ease of use and support.  

Lloyd Klein, Chicago, Ill.: There are both scientific and policy grounds NOT to require these devices. Scientifically, there really isn’t good enough data to say that these devices save lives, or are cost effective, or make a difference in shock patients. Yes, we have all seen great anecdotal cases. No, that isn’t sufficient to make this a standard of care.

From the policy perspective, this would absolutely close hundreds of programs in poor urban, rural, and community locations, which is exactly antithetical to the whole point of STEMI care. I think this is a roundabout away to go back to 20 years ago when some hoped to keep PCI among the select few academic programs. It is not right for patients.

Ajay Kirtane, New York, NY.:  Lloyd, I think that what is being asked is not whether these programs shouldn’t exist but whether they should in fact just get these types of devices (like all labs now have IABP)...

Chris White, New Orleans, La.:  I concur with Lloyd and agree that we must resist anecdotal evidence for newer and more expensive to dictate our practices… which can lead to increasing costs, with little benefit over conventional therapies. If there are niches where these devices excel, the manufacturer should be asked to provide comparative data to justify the additional cost. 

Moreover, the misaligned incentives for small, less well-equipped, and relatively low-volume hospitals and physicians to attempt PCI in these very ill patients, rather than to expeditiously transfer them, will likely change as we progress from “volume-based” to “value-based” programs.

Aaron Kaplan, Dartmouth, NH.: Sorting through how to integrate Impella into the treatment of our shock patients has been a challenging at a moderate-size academic institution. It has been less than straightforward, requiring us to balance the issues that have been highlighted in this dialogue. A bit reassuring to know that this is issue is a dilemma for many others as well.  

Gregg Stone, New York City, NY.: While the clinical need is great and the potential for advanced hemodynamic support intuitive, these devices are expensive and associated with a high rate of complications. There is no credible evidence from either randomized trials or registries that they improve outcomes (although they may — we just don’t know). Thus, I believe advanced centers should certainly have these devices available, and use them in shock and cardiac arrest patients, but while the evidence base is being developed, I do not believe they should be mandatory for all primary PCI STEMI programs.

Ajay Kirtane, New York, NY.: There are randomized data that show that specific devices (e.g., Impella, TandemHeart) provide greater levels of hemodynamic support compared with IABP (these trials were done in shock patients). While unproven in a randomized trial, it is a reasonable hypothesis that greater levels of hemodynamic support can forestall and/or prevent end-organ dysfunction and can allow institution of definitive or salvage therapies (e.g., reperfusion or transfer for recovery, bridging to destination therapy, or transplantation). This is why we don’t conclude that a support device specifically would have helped, but do feel that if some of these sites had an option for support, then perhaps this could have helped these patients survive.

In my mind, there are 3 options for hospitals performing STEMI and who don’t have advanced support (functionally Impella or ECMO):

1. Transfer shock patients out immediately. But this is difficult because shock evolves (and the immediate presentation may be very misleading).
2. Try to reperfuse patients using IABP alone (the current standard)…recognizing that there are going to be patients who are too sick to survive PCI or will get very sick after, and try to transfer them this way.
3. Pick an advanced support device/technology and use selectively for shock cases and/or transfer.

While there aren’t proven data that #2 would be any different with a more advanced device, having done these cases at our center with these devices, I wouldn’t want to do these cases without them. I recognize that may be a cop-out answer without substantiating randomized data. But that’s why I wanted to hear from OUS [outside the U.S.] colleagues who might not have these options.

The 4th option (not doing STEMIs without having advanced support for backup) is just not realistic and would deprive many patients of opportunities for reperfusion; I agree entirely with Lloyd.

Navin K. Kapur, Boston, Mass.: My bottom line is that we need an updated consensus around a STEMI/shock algorithm for primary reperfusion centers in the U.S. At this stage in the field of acute mechanical circulatory support, I agree with the view that all primary reperfusion centers should have an IABP at minimum and Impella is ideal, but cannot be mandated at this time.

Of course, the FDA labeling around Impella for shock may drive use over IABP in these centers — whether you agree with the dataset or not. Major resistance from community STEMI programs has been around reimbursement for Impella implantation, which was recently resolved, and we are now seeing more centers implanting Impella over IABP for STEMI/shock.

For smaller centers without Impella, IABP insertion needs to be followed by one device we haven’t discussed yet, which is a pulmonary artery catheter (PAC). If the PAC data shows minimal to no effect of the IABP within 1 hour in terms of resolving shock hemodynamics, this patient should either receive a cardiac unloading device — Impella/TandemHeart — on site or be transferred for Impella/TandemHeart implantation. Part of the problem here is a lack of education around how to best manage shock using hemodynamic data as a decision-making tool, especially as it pertains to mechanical support. The frustrating cases are the IABP transfers 6 hours after STEMI/shock revascularization with a lactate above 5, overt congestion, and kidneys that don’t work anymore — all of which might have been averted. 

I do not favor the use of VA-ECMO (ECMO with ventilation) in STEMI and shock in primary reperfusion hospitals. Aside from the resource allocation issue, VA-ECMO is a circulatory and pulmonary support pump [increases mean arterial pressure (MAP) and oxygenation], but does not provide cardiac unloading. For this reason, VA-ECMO in fact may worsen both cardiac and lung injury in the setting of STEMI, and further is associated with risk of cannula bleeding and limb ischemia given the mandate for larger bore arterial cannulas greater than 15 French in size. In my opinion, VA-ECMO without concomitant use of an IABP or Impella [as a left ventricular (LV) vent] should be reserved for cardiac arrest or profound biventricular failure.

As more device options emerge, we must have a growing educational program around shock hemodynamics and the timing of hemodynamic support devices in STEMI/shock.

Bonnie Weiner, Worchester, Mass.:  Navin, you make an important point. It has almost become “illegal” to put in a right heart catheter in the CCU setting. Not only do many of our more junior colleagues not understand acute physiology, but it is nearly impossible to teach it to our fellows anymore.

Lloyd Klein, Chicago, Ill.: Navin, although your algorithm seems to make sense hemodynamically, without a randomized, controlled trial it cannot be made the standard therapy. You and your center are welcome to follow something that seems rational, but the cost of what you are advocating is huge. We (I mean the USA) can’t afford something like this unless we have evidence that shows following it saves lives. And moreover, that it saves more lives than closing the programs that can’t do it will cost us. I think the days are long gone when policy is made on the basis of “sounds good”.

Jeffrey Moses, New York City, NY.: I agree with Navin that VA-ECMO is for the true crash and burn, and should be reserved for such. If that is not available, then these patients will simply die at these centers. I am equally concerned about the complexities of Impella, etc., in these smaller centers and would rather advocate for a rapid transfer policy for those patients since the decision algorithm needs a robust back end [receiving center] anyway.

Peter Berger, New Hyde Park, NY.: Ajay, I agree, it is an entirely reasonable hypothesis. But it has been disproven, no? IABPs provide a small amount of hemodynamic support and have been shown (so far) not to reduce mortality in shock. Impella provides more support than an IABP and (so far) has not reduced mortality. And TandemHeart provides even more support, and (so far) has not reduced mortality. True, every one of these trials has limitations, and some were very small, but I would argue that the current data suggest that hemodynamic support is not an adequate — is a disproven — surrogate endpoint for value in shock. 

Ajay Kirtane, New York, NY.: No. I wouldn’t say it has been disproven… rather, I’d say it is an open question in need of a current and adequately powered study. The limitations of IABP SHOCK II (device used, when it was used in relation to reperfusion, the varied patient population, not to mention the logistics of enrolling these patients) are substantial enough that I personally think it would be factually incorrect to conclude that “everything is disproved so use nothing at all”. The studies of Impella, TandemHeart, and ECMO are simply not adequately sized to even begin to look at mortality.

George Vetrovec, Richmond, Va.: No one has mentioned that Impella use for acute MI/shock has a very recent FDA premarket approval that adds significant credibility to the data supporting Impella deployment in the acute MI/shock setting. Thus, I am surprised at some of the negative responses to Impella use given the lack of IABP efficacy and the high risk these patients exhibit. As stated by Ajay and Mort, “doing nothing” is not an option. Furthermore, registry data reported by Bill O’Neill demonstrated a clear benefit for earlier Impella hemodynamic support in acute MI/shock.3

Where appropriate management is provided is not the issue, but if hemodynamic support is not available, acute MI/shock patients should be urgently transferred to an institution with the appropriate experience and tools, and with an Impella in place, if feasible.

Conceptually, Navin provides a cogent argument for MI/cardiogenic shock management. Cardiogenic shock remains the main cause of acute MI morbidity and mortality. Understanding hemodynamics as a basis for selecting advanced mechanical support is a first step and should be reinvigorated for short-term decision making in shock. Prior complications and lack of efficacy associated with right heart cath occurred when use focused more on improving outcomes for sub-acutely decompensated, chronic heart failure. A quick, diagnostic right heart cath in skilled hands is low risk for the information derived.

Thus, the issue isn’t expecting every center to provide complex care potentially beyond the capability of their setting; the issue is to encourage early transfers when local expertise and/or equipment is lacking to manage an acute MI/shock patient. Likewise, receiving centers need to become more focused on earlier, but appropriately based, mechanical support in their approach to acute MI/shock, with a goal of improving the outcome for this continuing challenge in acute MI management.

Mort Kern, Long Beach, Calif.:  Colleagues, I truly appreciate the exchange of views on this seemingly straightforward but ultimately complex issue. From the view of one of the smaller centers, similar to one that might be in the community away from the advanced centers of which most on this list are a member, the dilemma is quite acute. Transfer of the critically ill is not straightforward and to risk the patient dying in transit is among the perceived greatest sins suggesting poor care or poor judgment. However, we do believe in transport of the critically ill in the timeliest manner possible with hemodynamic support with either IABP or preferably Impella. Should we expect less from other “small” centers? A requirement of any kind “requires” strong data, and I understand we lack this.  

While it’s easy to say “no” [to Impella for small centers] from the high level, fully capable Mayo Clinic/Columbia/Duke-like centers, the translation of best practices and ability to implement them to the community practitioners is where our duty lies to help them do the right thing for the patient. Randomized data has its important role, but as Jeff Moses and others stated above, we do not and may not have enough data, and must decide on usage based on what the surrogate hemodynamic support strength as an end point suggests. An arguable position, of course, but that’s my quick overview.

The bottom line

Ted Feldman, Evanston, Ill.:  Having posed the question at the beginning of this discussion, thanks to all for an animated exchange! We have a 4-hospital system with a spectrum of practices and experience, and this is the discussion we are having internally. In addition to the considerations of therapeutic benefit, there are safety, cost, and logistical considerations that are all substantial. 

Mort Kern, Long Beach, Calif.: While there is certainly no clear answer to this question, I believe we have learned quite a bit about where the important issues lie and what each center has to consider in their STEMI and high-risk PCI program.

References

1. Page RL. The US Food and Drug Administration Premarket Approval Process and the 515 Program Initiative: View From a Panel Chair. JAMA Cardiol. 2016; 1(2): 119-120. doi:10.1001/jamacardio.2016.0007.
2. Rathi VK, Kesselheim AS, Ross JS. The US Food and Drug Administration 515 Program Initiative: Addressing the Evidence Gap for Widely Used, High-Risk Cardiovascular Devices?. JAMA Cardiol. 2016;1(2):117-118. doi:10.1001/jamacardio.2016.0002.
3. Cohen MG, Matthews R, Maini B, Dixon S, Vetrovec G, Wohns D, Palacios I, Popma J, Ohman EM, Schreiber T, O’Neill WW. Percutaneous left ventricular assist device for high-risk percutaneous coronary interventions: Real-world versus clinical trial experience. Am Heart J. 2015 Nov;170(5):872-9. doi: 10.1016/j.ahj.2015.08.009.