7.2 / IAGS 2019
Session 7: Hemodynamics Session 1
Hemodynamic Support for High Risk PCI: In Whom and How to Integrate the Skills Necessary for Best Outcomes
Problem Presenter: Sundeep Mishra, MD
Statement of the problem or issue
Over the past 3+ decades we have developed a multitude of devices, from the IABP to ECMO, all designed to support cardiac function. Despite the available options, ventricular support devices are not all the same, with some designed to more indirectly improve cardiac function (IABP) and others designed to primarily impact LV mechanics (Impella), while others support the entire circulation (ECMO). One must understand the differences in order to make an informed decision on the appropriate device for a particular patient. An additional issue with appropriate selection is the data set on which the decision must be based. The need for companies that make the devices to gain expanded approval of their device has driven some of this problem: in the United States, approval can be obtained without rigorous data to support their expanded use (510K process). This has led to expanded approval based on inadequate data on which to make informed clinical decisions. Layered onto all of this are the financial issues with payors (expensive devices), particularly in the United States, with reluctance to reimburse a procedure when there is a lack of firm evidence to support its use in specific populations.
Gaps in knowledge
The evidence base on which to make the decision to support someone undergoing high-risk PCI is incomplete. This is primarily due to the heterogenous patient population that might require support (from MI with cardiogenic shock to unprotected left main), the types of support available, and variable inclusion criteria used to define the population that might benefit from a given technology. Most sites actively involved in intervention in this complex patient group have developed their own algorithms such that the definition of an appropriate patient has been a bit like the definition of pornography: “I know it when I see it,” rather than basing the assessment on more rigorous and consistent criteria for high risk intervention.
Possible solutions and future directions
While one can almost always state that we need more data, this area is ripe for more data to inform our practice. But before we ask for such, a very strict, universal definition of high-risk intervention is needed, too. With that, not only are randomized trials designed better, subsequent meta-analysis will be simpler to perform as well, realizing that large trials in this space are difficult. A universal definition would also allow well-designed registries to be used to inform our practice. The cVAD registry is a start, but the ideal registry doesn’t include just one device, it should include all devices used in patients who meet the registry definition of high-risk PCI. It is unlikely that industry will have an interest in supporting such a registry, but perhaps governments or professional societies could lead that charge and financially support the effort. We must also deal with the question of where these procedures are best performed, since some devices, e.g. Impella, are relatively easy to place. That fact, however, doesn’t argue for these procedures to be performed without adequately trained staff who have frequent exposure to their use and the infrastructure to care for these complex patients.
We must also be willing to randomize patients into trials and treat them as the protocol arm indicates. Despite a number of trials in this space, we clearly still have clinical equipoise in many patients, so we must be willing to submit patients to well-designed trials and not fall into the trap of innately knowing “what is best for my patient” and then refusing to randomize them. These devices, in their current state, have significant potential complications and expense which also begs the question of which device for which patient, or importantly, perhaps no support due to futility. This becomes all the more important in a world of ever-increasing surgical turndowns due to high surgical risk. We must know which device to use and who will benefit from this technology before we apply it. To quote a past surgical mentor of mine “just because you have a technology doesn’t mean you need to apply it.” Sage words that continue to resonate all these years later.