I do have the following disclosures, none really particularly relevant to this talk. Really the history of surgery for PE is the history of cardiac surgery. John Gibbon, who was the first developer of the heart-lung machine, made it his life mission to make the heart-lung machine because of a young patient he saw die of a PE. And so his whole goal was, how could I in the future save that young woman's life? And so with that, he invented the heart-lung machine, which allows us to do cardiac surgery today because of the heart-lung machine. It took about 25 years before it was put into clinical practice, but clearly was very, very successful with the work that he did. Unfortunately, surgery in PE has very limited data. We know it occurs, but it is very limited. As you saw, a lot of the treatment for PE is based on minimal data. Most that you see reported is single center studies. The biggest review I found was 50 years of data with 1,600 operations. That's not very many over 50 years. We do know in the ELSO registry, for example, there's about 3,000 patients that have been treated with ECMO for PE in comparison, and those have about a 50% survival. We don't know some of the other details, do they have surgery and then get ECMO? But it is good to know that that's how many are in the ELSO registry right now. So what are currently the indications for surgical embolectomy, or what have they been in the past? Typically, it's failure of some other treatment of a massive PE, so whether that was thrombolytics that failed or catheter-directed removal of the clot that has failed with ongoing hemodynamic instability or right ventricular failure. One of the indications has always been the inability to receive thrombolytics, for instance, bleeding risk. However, I'm not sure that's always a good indication for an operation that requires tens of thousands of units of heparin, potentially cooling, and a long operation. But that is still kind of an asterisk indication for surgery versus the catheter-based options. And then if you have a clot that's especially straddling a PFO in a patient, because of the risk of left-sided embolization. Although even in the OR, it can be difficult to remove that thrombus without having thrombus enter into the left-sided circulation. So for instance, in the OR, we have to be very careful not to manipulate the heart if we know that that exists, so that we don't cause it to embolize just as we're getting on bypass. How the surgery is performed. We go on bypass. I do cool when I do these. I don't cool as much as I would for a chronic emboloptomy, but I still do cool because that allows me to drop flow on bypass to see better when I'm doing the operation. And my first incision I make is in the main PA out into the left main PA. And if it's a big saddle embolus, it'll be sitting right in front of you, and you can typically just use forceps and pull the majority of the clot out directly. It's usually very satisfying to see, kind of like the pictures you showed. You can hold up the clot, and everybody takes a picture of it. You can put it in the chart now with that fancy epic photo thing, so everybody can see the clot that you removed from the patient. So the central clots typically are relatively easy to remove. What's more difficult is if they become more distal. So you can try with instruments to reach further down into the PA, but you may actually cause them to embolize more distal into the lung versus actually pulling them out. The other risk is of injuring the arterial wall when you're doing that, and causing life-threatening bleeding into the lung parenchyma. Next, we can open the right main PA separately. So we actually dissect the SVC and the aorta, and we'll open between the two. And then you can reach down into the right-sided PA structures to remove any thrombus. And then you can repair these either with a patch or with primary repair of the PA, just depending on the quality of the tissue. If you feel like you have a lot of distal clot that you've not been able to reach, we can open the left atrium. And like we do for a lung transplant, where we retrograde flush the donor lungs, so give flush into the pulmonary veins, and it comes out the PAs, which, by the way, is my favorite physiology of the whole body, the fact that there's no valves in the lungs, and blood can go either direction. So you can actually flush each pulmonary vein, and then have the clot come out of the pulmonary artery if you feel like you have a lot of distal clot that you've not been able to flush out otherwise, or grab out with your forceps. And then when you do these operations, it's usually a pretty dramatic specimen. You can see how large and how dense the clot is. And when I see these every time, I think, how would thrombolytics ever have made this go away? It's hard. It's dense. I can't imagine that you'd get a lot of bang for your buck with trying thrombolytics. Sometimes these are done just because you don't have availability of, say, some of the other devices. And some of these are a little bit of older cases where we didn't have as many devices then to be able to do the embolectomies. Another time where really surgery is the right answer is tumor thrombus. So this was a renal cell cancer. It was a patient in the OR getting their renal cell removed. They appeared, they thought they'd be able to get the whole tumor out without having to open the chest and go on bypass. But as soon as they removed the kidney, the patient arrested, and they were able to see on TE there was a large clot burden in the PA. So we opened the chest emergently, went on bypass, and were able to remove a lot of clot from the lungs this way. The outcomes from surgery for PE, the reported in-hospital mortality varies a lot, 6 to 29 percent, and some case series even higher. More recent but small studies say it's more in the 6 to 12 percent range of people that die after surgery. It's relatively equivalent in survival to medical management, such as thrombolytics or catheter-directed removal of the clot. But long-term, we may have more patients that don't survive, it's unclear. And also, the long-term outcome is typically affected by their underlying conditions, you know, especially if they have an advanced malignancy, and that's what led to them having the PE in the first place. This operation is very different than the chronic embolectomy. So for chronic thromboembolic pulmonary hypertension, that's a pulmonary thromboendarterectomy. So it's actually removing the intima of the pulmonary artery in addition to the thrombus. So much more involved, complicated operation. It needs to be done under deep hypothermic arrest, typically 16, maybe 20 degrees centigrade is how you cool the patient. And you actually have complete circulatory arrest. Typically you can go 30 minutes, and then have to rewarm the patient, give perfusion back, or not rewarm the patient, give perfusion back. You can arrest the heart again, empty the blood out of the patient, and keep working when you're that cold. And you sometimes will have an hour to an hour and a half of no circulatory time while you're doing these embolectomies. And it does remove, as you can see in this specimen, the intima as well as a lot of the thrombus material. It is a very meticulous operation, removing each branch of the PA to remove any material that may be present. There are very few expert centers in the country that do these. Probably the most well-known is the University of California in San Diego, where Stuart Jamison was that did these operations. And they have 1% to 2% mortality from these operations, which is truly incredible to get that kind of result for such a difficult disease to manage. And about 4% of patients that have a PE may go on to develop CTEP. So it's a relatively small patient population, but an important patient population as well. So really, in summary, I think with it now, we have the availability of the catheter devices to remove PE. Surgery has become a last resort when nothing else is working for that patient, or, for example, on the patient that was already in the operating room and had an arrest from the tumor PE. And so hopefully, with the availability of these devices, we'll be able to have better access to care for patients and not limited to a few centers that can do a surgical embolectomy, as well as better outcomes for those patients as well. Thank you.

pulmonary embolism

surgical embolectomy

heart-lung machine

catheter devices

thrombolytics