Hemodynamics

A Peripheral Fem-to-Fem Bypass With Impella Use

Cath Lab Digest talks with Wissam Gharib, MD, FACC, FSCAI, West Virginia University Heart Institute, West Virginia University Hospitals, Morgantown, West Virginia, about his use of the left ventricular assist Impella device (Abiomed, Danvers, Mass.).

Can you tell us about your cath lab?

The West Virginia University Heart Institute has 3 dedicated cath labs with another lab mainly used for electrophysiology procedures. We do between 1,200 and 1,400 interventions per year, and up to 3,000 caths per year.

How long have you been using the Impella device?

We have been using the Impella for 2 to 3 years, beginning a few months after it received FDA approval. In the beginning, we were using it for very high-risk interventions, usually the last conduit available, and very low ejection fractions (EFs). Over time, as we have become more comfortable, we have been using the Impella on a wider variety of patients. We have used it in cardiogenic shock on multiple occasions, particularly in the setting of an acute myocardial infarction (MI), and have seen very favorable results. We still use it in the traditional setting for high-risk percutaneous coronary intervention (PCI), surgical refusals and such, but we are also using it more in the acute setting.

Initially, there was somewhat of a learning curve, specifically in terms of the pump management, with the cath lab team and our hemodynamic team upstairs. Currently, however, everyone quickly became very comfortable using the Impella in the cath lab, and if we have to leave the device in, the perfusionists in the ICU are able to manage the pump for as long as we need it.

From a procedural standpoint, what does the Impella offer?

While the patient is on the Impella, their stability allows you to take your time and do what is necessary for the patient. You are able to treat more lesions in the same setting as well as more complex lesions including rotational atherectomy. When you are working on an unprotected left main, and want to post-dilate the lesion, and use advanced techniques taking longer inflation times. Before the Impella, when we did unprotected left mains, it would be very quick – balloon up, balloon down, stent up, balloon down, and then get out. Now, we are more comfortable using intravascular ultrasound, pre and post stent. We use more aggressive debulking techniques, and proceed with balloon angioplasty, stent placement, non-compliant balloons, etc. We are able to get a more complete revascularization, and then reassess it after we are done. Basically, we aren’t in a big hurry to get done because we might be worried about the patient’s stability. As a result of the support that the Impella provides, we are able to take our time and do what is necessary.

Can you share a high-risk case where the Impella was used?

Recently, we did a very sick patient, who presented with cardiogenic shock as well as septic shock. The patient had mixed shock, requiring multiple vasopressors, and a very low EF on the echo. We brought the patient to the cath lab, placed a Swan-Ganz catheter, and decided to proceed with an Impella device in order to help with stabilization. Since the patient had so many pressors on board, there was significant vasospasm on the right side around the Impella sheath. On the left side, there was a 90% stenosis in the iliac artery. We placed the Impella, and once we were up to full support, the patient didn’t require as much pressor support. We were able to back off some of the pressors, so we knew that it was very necessary to keep the Impella in. However, the patient’s right leg became mottled, and there was no flow down her right lower extremity. We had to make a decision — do we keep the Impella in and save this person, to the detriment of her extremity? We decided to keep the Impella in. At that point, we ballooned the stenosed left iliac artery, placed a small 4 French (F) sheath on the left, went antegrade into the superficial femoral artery just distal to the Impella on the right and then connected the two 4 F sheaths together, allowing perfusion of the patient’s right leg. Essentially, a peripheral fem-to-fem bypass allowed us to keep the Impella in and continue perfusing the patient’s leg. Whether you are using a balloon pump or Impella, if the device is helping the patient, and if the patient has peripheral vascular disease, significant spasm, or very small arteries, there is a way to continue to perfuse the leg in the cath lab. We sent the patient back to the ICU with this peripheral bypass.

From a technical perspective, how easy is it to do this kind of bypass?

It is somewhat difficult to place a sheath antegrade when a sheath is already retrograde in a patient with no flow down that artery. You have to go blind and try to figure out where the artery is, because there’s no flow. Normally, if you are sticking antegrade, it is not very difficult if you have a pulse. In this particular case, the patient had no pulse down the leg, so it was difficult.

Knowing we can bypass that blockage by performing a peripheral bypass is a very simple concept. In this case, we happened to hear that someone had done it somewhere else, so we just went ahead and gave it a try. We do a lot of peripheral work at our facility as well — we have done very small sheaths and people with very poor flow. If you have not done any antegrade sticks, you would not want this to be your first. An experienced peripheral interventionalist should place the antegrade sheath.

What was the outcome?

The patient was very ill with multiple co-morbidities and unfortunately, did not make it. The patient had septic shock and cardiogenic shock, as well as multiple other problems.

This case is basically just a proof of concept. In very sick people where you want to use an Impella, but other problems preclude it — if you feel that a left ventricular assist device is absolutely necessary, this case shows there is a way. Obviously, it is preferred that the Impella device be used proactively, because the last thing you want is be working on an unprotected left main or a last remaining conduit, and have a dissection.

I have many conversations with other cardiologists who say, “Well, I can do this without support,” and that is true. We have done it without support for years. Stents were approved in 1994 and we have been doing unprotected left mains, last patent arteries, for years. However, we have not been this aggressive during that time period. We have become very aggressive because of the support that the Impella gives us. But here’s the problem. If you are doing an unprotected left main or a last remaining conduit, and you get a dissection, it becomes a much more difficult endeavor to fix these problems without hemodynamic support. It is very difficult to keep the patient stable while you are trying to fix the dissection. If you have the support of an Impella device or some sort of left ventricular assist device, then you are able to deal with the problem without making it an emergency. The patient is stable while you are fixing that dissection, occlusion, or plaque shift you have caused. Being proactive about placing the device in these patients allows for the procedure to be done in an elective fashion rather than in an emergent fashion — and that’s where it helps us.

Dr. Gharib can be contacted at wgharib@hsc.wvu.edu.

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Disclosure: Dr. Gharib reports he has spoken on behalf of Abiomed in the past.