A Minimally Invasive, Mechanical Cardiovascular Support System

What is the Impella® Recover® LP 2.5 System? The Impella Recover LP 2.5 device is a percutaneous ventricular unloading catheter. This is a 12-French catheter, placed in the left ventricle, which utilizes a transaxial flow pump to transfer blood from the left ventricle into the ascending aorta. The pump can deliver as much as 2.5 liters of blood per minute. Essentially, the Recover LP 2.5 System increases cardiac output, thereby increasing end-organ perfusion. In addition, by unloading the left ventricle, it reduces myocardial workload and oxygen consumption. We suspect that this device would be useful for treating patients in cardiogenic shock, because it unloads the ventricle and may allow for more complete ventricular recovery. However, there is a variety of other patients that are also likely to benefit from this technology. It’s still in the early stages, so it’s difficult to know exactly which subsets will benefit the most. Most likely it will be patients who: 1. Have acute significant left ventricular (LV) dysfunction; 2. Are at high risk for the development of LV dysfunction during PCI. What kind of patient improvement can we expect from using the Recover LP 2.5 device? Since it’s not only unloading the ventricle but also improving cardiac output, we should see improvements in many end organs, resulting in increased coronary perfusion, cerebral perfusion, and renal perfusion. How do you determine the necessary blood flow rate? Determining optimal flow for each patient is a trial and error process. In terms of peak flow, we are limited to 2.5 liters with the percutaneous device. The operator would adjust the console and would evaluate the results by simultaneously assessing wedge pressure, cardiac output and urine output and blood pressure. What would we see if the flow rate was too strong? We probably would notice a rapid drop in the left ventricular filling pressures and perhaps even a slight fall in overall systemic pressures. However, since the pump can only produce a maximum of 2.5 liters of blood flow per minute, this is less likely to occur. Does use of the device affect the administration of any agents? No. It doesn’t seem to be incompatible with any of the drugs or other technologies that we use in the cath lab. Does it ever need to be used in conjunction with a balloon pump? It could be used independently, or in addition to a IABP. There are trials now which are in the process of comparing the two methods of support. How is the ventricular wall affected by the pump? The distal end of the pump is connected to pigtail catheter to prevent trauma to the LV wall. Blood is aspirated through the tip at the end of the catheter through the pump assembly, and out into the aorta. None of the animal models have demonstrated any damage to the heart muscle itself, even despite the very high flow rates in the larger systems. How long can the patient be supported by the Recover LP 2.5 System? The clinical data on this is up to five days. It could be a possible bridge for transplant, but there’s not enough data to know the long term sequelae. The original concern was that significant flow through the pump could result in hemolysis. Fortunately, that doesn’t seem to be a problem. The Recover LP 2.5 System appears to be a relatively safe device; its only limitation is that it requires delivery through a 13 French peel-away sheath, which may be large for some patients with peripheral vascular disease. Would patients typically need to be supported for up to 5 days? It depends on the cause of their LV dysfunction. We’re hoping that the Recover LP 2.5 System, in addition to other procedures including revascularization, results in the unloading of the ventricle, and a more rapid recovery and removal of the device. What types of cath lab patients will benefit most from use of the device? The device success will ultimately be determined by the outcomes of other interventions. For example, in a patient that has a fairly large myocardial infarction, we know that early reperfusion can potentially salvage myocardium. Despite successful reperfusion, there is a period of time during which there is significant LV dysfunction that potentially would benefit from unloading therapy. We believe that the Recover LP 2.5, by unloading the ventricle more effectively than a balloon pump, may allow for more rapid recovery. The SHOCK Trial evaluated patients in cardiogenic shock; even with successful revascularization, there was still a 50% mortality. We’re optimistic that devices like the Impella Recover LP 2.5, which may unload the ventricle and allow for a faster recovery after the initial insult, will improve outcomes substantially. Another potentially large application for the device will be the high-risk patient undergoing PCI. We have been using the IABP for years, but there are times when the support is inadequate. Having an alternative support option would be a welcome addition to the cath lab. The larger percutaneous Impella Recover LP 5.0 unloading catheter can generate 5 liters of blood flow per minute. Since the catheter is 21 French, it’s not a percutaneous system; it requires a cut down. The larger system would certainly offer more support in a patient that’s even more hemodynamically compromised. How quickly can the Recover LP 2.5 device be deployed? The limitation is really only on how quickly you can place the pigtail catheter across the left ventricle. The actual flow pump is connected to a very short pigtail that can be placed percutaneously from the groin, like a balloon pump. The only difference is the final position of the devices; the IABP is placed in the descending aorta while the Recover LP 2.5 is placed across the aortic valve. What is the status of the U.S. feasibility trial? The current U.S. feasibility trial is actually evaluating the larger platform (the Recover LP 5.0), which requires a cut down but can deliver up to 5 liters per minute. This trial is currently assessing the outcomes of 20 patients with cardiogenic shock in about half a dozen U.S. centers. The trial has been very slow to enroll, mostly because the time window for enrollment is very tight; you have to enroll the patient within 6 hours of the onset of cardiogenic shock, which can be difficult. The enrollment time window was recently increased to 24 hours, which should increase enrollment. In addition to the current clinical trial, there is another trial design under review for the smaller percutaneous system. It will assess the Recover LP 2.5 System in high-risk PCI patients. What about the European experience with the Recover technology? I know that they have European approval for the Recover LP 2.5 and 5.0 Systems, and the Recover LD (surgical placement into the LV) and RD (surgical placement to support the RV) Systems. The majority of the European patients have been treated with the Recover LD or LP 5.0 Systems, with promising outcomes. Also, there has been encouraging use with the Recover LP 2.5 percutaneous system. A recent live case demonstration with this device at this year’s CRT and EuroPCR demonstrated its simplicity. What are your thoughts on the Impella Recover LP 2.5’s ability to reduce infarction size by increasing cardiac output? It’s not only increasing the cardiac output but unloading the ventricle that is important. The major reason for the reduction in infarction size is the ability to reduce myocardial demand by decreasing the size of the heart. You cannot obtain as much unloading with the balloon pump as you can with the Recover LP 2.5 device. Preliminary observations indicate that the chamber size is much smaller when the Recover LP 2.5 System is running. Any intervention that reduces the chamber size decreases the amount of pressure and wall stress, thereby reducing myocardial oxygen consumption and likely allowing more efficient recovery of function. If it proves safe and effective, what do you see happening in the U.S. with this technology? I believe that it will be widely adopted, particularly in the sickest patient group. The major limitation will be its size. We’re hoping that future generations will even be smaller to allow for use in patients with more extensive vascular disease. If it is superior to a balloon pump in the trials, then it will become a device of choice. If it’s equal to the balloon pump, then we will need to review select subsets to better identify its other strengths.

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