Summary
Notes
Transcript
The most common approach to get access to the heart is to split down the sternum, which is exactly correct. on the top of the heart. There are some other approaches currently that you can approach it from the right thorax. You can make a small incision and you can access from the right. You can also access it from the left.
For some minimally invasive procedures, you can do that. You can do the sternum with partial incision, which is known as hemisternotomy. But if you really need a good access completely, and for most cases, you need to split the sternum from top to down, and
That will get you straight down to the heart.
This is what happens when we open up the sternum, and we open up the sternum, and we put the retractors. Then as you know, the heart takes blood from all the veins and it pumps out to the arterial system where it forms a circulation. One of the biggest attachments in cardiac surgery,
In the last 60, 70 years is the fact that human beings were able to do two things on the heart. One is to keep the heart bloodless in a way they can divert the blood away from the heart. This is done by putting tubes. That will collect the blood coming back to the heart, which is mostly in the right atrium, or in the vena cava, and take it out and put it in a heart pump, a heart-like machine. And that heart-like machine will oxygenate, take out the carbon dioxide.
and put the heat in and out of the heat and can be placed back into the aorta. So, you put a tube in the right atrium. You take it out into the machine and you put it back in here. So, when you do this, the heart becomes bloodless, which is one of the most scariest things in cardiac surgery. You touch the heart, the heart bleeds and the patient is going to die.
So that's one of the most basic things in cardiac surgery, that you can take out the blood, put it in a machine, and bring it back. The second thing we were able to do in the last 70 years, the most important step in cardiac surgery, was that because the heart is a moving organ. It moves and it makes surgery so difficult. So people came with the idea of stopping the heart. This is based on the action potential, basic physiology that you know.
So by putting specially potassium, excess potassium in the extracellular system, that you can stop the action potential. So if you put a delivery system into the coronary arteries, the coronary arteries will take the potassium and the myocardium will stop.
So the other thing you can do is that you put some sort of needle in there and you inject a high potassium solution and that will stop the heart. So if you can get a bloodless heart and if you can stop it, that you can perform cardiac surgery. It has the basic advances in cardiac surgery.
cardiac surgery or mid-cardiac surgery also. As you may know, the most common cardiac surgery globally is coronary artery bypass grafting. This is because of the burden of coronary artery disease, especially in the West. I don't suppose that this is related to the simplest surgery in relative terms.
of cardiac surgery. So coronary artery bypass grafting is the common spot. 60-70% of most cardiac surgeries will perform coronary artery bypass. So, as the name implies, if you have a coronary artery blockage somewhere in the main coronary arteries, which is namely the right coronary artery, the left anterior descending, the left circumflex, or the tributaries of this main artery,
arteries. And if that blockage is going to diminish the blood supply to the myocardium, the myocardium is going to get weak. Sometimes it's going to get infected. So you need to give it a new blood supply so that the heart keeps pumping well and the patient is going to be doing relatively better. For that, if there is a blockage here, you have to somehow find and put another artery, another blood supply here.
So to do this, you have a couple of options. One is to take the internal thoracic artery, which is commonly known as internal mammary artery from its past name. So you take the internal mammary artery, which is a branch of the brachiocephalic artery. on the left side, which is in close proximity to the left anterior descending artery, which supplies most of the blood supply to the anterior part of the left ventricle and the septum of the left ventricle or the heart.
So if you take the left anterior torus, the left internal torus carteri from the back of the sternum, mobilize it, divide the branches that it gets into the intercostal spaces, and at the end before it bifurcates into its two terminal branches, which is the musculofrenic carteri and the superior apigastric carteri, if you divide it,
There you have a direct blood supply from the aorta. So if you can take that one and bring it here, and if you somewhat manage to stick it so that the blood flow can continue, this will supply most of the heart. The other options you have is that you can take the right corner, the right internal to askars-carta as well, and you might be able to put it either on the right side or...
It is a common approach, though. You might be able to take veins from the leg, as you know. The other option is that you can take a saphenous vein and you can put it between the aorta and the other coronary arteries.
So you can take a saphenous vein from the leg. You have a couple of options of doing this. One is open harvesting of the saphenous vein. The saphenous vein is as you see superficial, it's long and because of the deep vein you're not scared of causing significant damage to the patient as long as there is no DVT in the deep venous system, but in that case you shouldn't, but as long as these three factors are fine you can take this vein.
So you can take it either in open fashion or you can endoscopic fashion, which we just make small incision here and subcutaneously we can just take the entire vein if you want to. And the other option we have is the radial artery. The radial artery, as you know, the arm has a dual supply from the radial and the LR. And because of the circular circulation, the parameter aspect, and because the LR artery is more dominant than the right radial artery,
It has been edited to include proper punctuation. While you release the pressure on the radial, but keep the pressure on the ulnar, that means you are trying to mimic there is no blood supply coming from the ulnar artery. If the hand becomes pink again,
Sorry, keeping the pressure on the radial, but you release the pressure from the earner. If the hand becomes pink again, It's like you are occluding the radial artery externally. That means the lateral artery can sustain the hand. This, you can do this in a modified fashion by putting a SAD probe, and you put the SAD probe specially on.
First and second digits because this is a main blood supply is from the radial artery and again the same thing you put the pressure on the radial artery or the radial side of the hand. and the medial aspect of the forearm. And then after a while, you release your pressure from the ulna, but keep the pressure, sustain the pressure on the radial.
and see the tracing on the monitor. And if you have the wave of the pulse oximetry still, that means the blood supply, the collateral blood supply from the LNA is good enough, which means you can safely take out this radial artery. This radial artery can also be taken either in an open fashion or in endoscopic way, which means you make a small incision here and you can cut it with a minimally invasive approach.
For most of the history in the last 70 years, most of the procedures in coronary artery bypass grafting, as in cardiac surgery, was to split the sterum open and get access to the entirety of the Most of the anterior lateral heart but nowadays people are coming, people have already come with the idea of making a very small incision and
I'm going to show you how to do it. I'm going to show you how to do it off-pump. As I said in the beginning, the pump helps you to drain the heart. In this case, you don't put the pump on. You don't put it on. the blood to come out from the patient, go into the pump, and come back into the aorta. Because the pump, while it is so helpful, it has its own drawback that the fact that blood is coming out of the patient is going into a tubing system and coming back into the patient.
Temperatures changing into contact into different surfaces and at the same time being compressed by a roller pump will cause lots of inflammatory response, platelets, dysfunction, hypothermia, all those things. have some effect on the patient's physiology. And the patients might take some time to completely recover after the PAMP.
So some people came up that especially when with a coronary artery bypass grafting, we don't need to open the heart. The heart is not going to bleed. So why do we need to do that? Why if there is a way we can do the second part of the surgery, which is make the heart stable.
We can do the surgery because it's going to be very minimal. We are only dealing with the artery. In valve surgeries, you have to open up the heart, which means the whole content is going to come out. So that's what we're going to do. That is going to make it difficult, but for the arteries, which are on only the surface, the heart can keep pumping. We don't need to stop it if we can stabilize it. So they came up with stabilizers. So these are stabilizers.
Stable others, as you can see, you can put them either directly from this port or even through the open sternum or through small holes like this. This will go and will. We suck on, have a suction effect on the top of the heart, somewhat stabilizing the only part of the coronary artery you are interested.
the other part of the heart will keep beating. So, if you do that, that part close to the coronary arteries, that will be relatively stable while the rest of the heart is pumping. And if you cut the artery, that small artery open, you can, in the meantime, either put a small shunt so that you can keep the flow from the distal and the proximal parts of the artery, or you can blow a carbon dioxide and a saline to clear it. You can, you are able to graft that
Which means you can completely avoid the consequence of.
The blood going into a pump and coming back, and all the inflammatory responses that come from the fact that the blood has come out and come back to your body again. So this is, it's called off-pump coronary artery surgery. It has been, it has gained lots and lots of
Reputation, the last 20, 30 years. And now it is becoming even minimally invasive without opening the sternum. You can go through small holes and you can. Put the section caps and you can go ahead with the procedure.
So, now, as in general, in any surgery, things have advanced to robotics. So, these days, You can do it with a robotic system that the surgeon will sit in a console and his movement will be translated by the robotic hands and this is more precise. But it has a chance to be dismissed from a couple of prisons.
One is simply old age, lots of shear effects, shearing effects through time. So it might degenerate, sometimes might be rheumatic heart disease. Sometimes it might be a bicuspid aortic valve instead of a tricuspid aortic valve. So these things in general will give you an abnormal state. Like you can see this is how it's supposed to open. It opens up, lets the blood come from the left ventricle into the entirety of the aorta and circulates.
When it closes, it effectively closes. Blood will, these valves will And when it closes, it doesn't close well, which means it's going to regress it back to the left ventricle. The left ventricle has to accommodate that one. Next time it has to pump more. It's going to come back. So the left ventricle is going to...
have either a deletive adaptation or a hypertrophic adaptation.
So this is what a normal valve looks like and this is what a diseased aortic valve looks like. You can see there is, because of the shearing effect, too much trauma. There is a calcium that deposits. around those valves, and the valves have lost their symmetry. You can see this is bigger, this is smaller, and there's too much calcium. This doesn't open, or even if it looks, it does close well, it doesn't open well.
So patients suffer with this. So what do we do when we have such a valve? When we have such a valve, we have basically two options. One is to open it up and put another synthetic valve or to Currently, we can do an approach. We can go through the femoral artery, go up into the aorta, and we can implant an expanding valve.
Whichever way you like to call it. So we have these two outputs. The TAVI is relatively new. The R2Valve replacement has been there for a long period of time. So what kind of valves you have? You have basically two types of prosthetic valves. These are, one is a mechanical valve and the other is a synthetic valve. These three are synthetic valves.
The mechanical valve, the reason we call it the mechanical valve is that it is, there is nothing of a natural tissue in here. So it's made of basically of a carbon and some When the left ventricle pressure is high and the right ventricle pressure is low and the right ventricle pressure is high, it closes, it reflects and it flattens and closes.
So this goes on and on. The advantage of the mechanical valve is that, in theory, this is going to last the rest of the patient's life. It's not going to break easily and unless something else happens, if you have it, you have it for the rest of your life.
What can happen that this thing might fail? Very occasionally, there might be some clot forming around here, and that doesn't let the valves to open and close. And the biggest fear we have is that this might get infected because it's a foreign material and you might have a prosthetic valve-infecting endocarditis, which is a very scary but realistic thing that happens a lot.
The other thing is that very rarely these things might fail, but this is very rarely there is a structural failure. So in general, for all practical purposes, once you have a mechanical valve, the patient has it for the rest of his life. So in a young patient...
This is a preferred type of valve. So you have it once, one surgery, this is the rest of your life. The only problem is that because this is a prosthetic, a synthetic material, a clot is going to form. When a cloth is going to form it's going to be a problem because it's going to block it anyways. So for that you need to have anti-coagulation. So if you have a mechanical valve you are going to be bound to have
a bulletiner for the rest of your life. So that's the drawback with that one. So some patients
Oh, sorry. I don't know what happened to my present.
Sorry, I don't know what just happened.
What is the problem that you're trying to fix? Stop sharing, just give me a second. Because we can still see your screen. You can see my screen? Yeah. Oh, it's still on the aortic valve surgery page with the four different valves. Yeah, that's correct.
Let me see. Sure.
Okay. Can you see now?
We can see it, yes, and we can see your mouse moving. Okay, good. Okay, I'm going to continue. So, the other options we have is that prosthetic parts that are made of This is a voice memo. It has been edited to include proper punctuation. It has been edited to include proper punctuation.
Since they are of natural organic material that come from other organisms, even if they are xenografts, they don't form clots. So if you have these things, there's no need for you to take a blood thinner naturally. Probably the maximum for three months and I've been trying to push it. But other than that, there's no need to take a break, you know, just like this for the rest of your life. The problem is that since these things tend to go into a tear and wear effect and they are.
Or a patient is old when we assume that the patient might die before there is a need to do the valve.
So for optic valve surgery, the same thing, we put the blood into a pump, we make the heart still with a solution known as cardioplegia, and then we put the valve in an open surgical fashion, or as I said, you come from the femoral artery, you go all the way from the aorta, and you can implant without any surgical intervention.
This is a transcatheter of the pulmonary implantation, or TABI. This has become more and more dominant these days. Because of the ease, it's fast. You can do it in an hour or so, and patients go home. And you can put it in a second valve after a while, depending on the size of the valve, the previous valve. The other valve we are going to discuss will be the mitral valve.
My travel was in latitrium and latventricle. It has partitions, which is callopsy, which is... the left ventricle. So, it is close to the aortic valve and sometimes there might be this extension from the mitral valve to the aortic valve through the aorto-mitral valve continuity.
So, the mitral valve, as you can see, one of the pathologies it can have is that it has a papillary muscle and there are cortex that actually anchors the mitral valve and reflates to the cortex. left ventricle. So sometimes there might be a disease in the fibroelastic mechanism of this chordae that this chordae might rupture.
When this ruptures or comes too loose in some fibroblastic disease state, the two valves of the mitral valve do not come together and they don't co-act. So in this case, there might be a recurrent defect. So as you can see, some of the fibers, the cord is microtracture, and this doesn't close properly, or so redundant, or so lox, it doesn't close. This is called fibroelastic disease. The word was formed, it's called.
bar loss disease. So even for that, people have come up with a transcatheter placement of a mitral valve coming from. This is not a mainstay. This is more of a... Anecdotal practice. The trans-catheter-optic valve placement is the mainstay currently. But the trans-catheter-mitral valve is not a common practice.
The other disease we are going to discuss will be the aorta. The aorta has, you know, have descending parts, including the ascending head arch, which gives the major branches to the head and the arm. and the descending aorta, which causes the rest of the body. So because of the pressure in the aorta, sometimes the pressure might split the intimate surface of the aorta, which is the intima, which comes close in contact with the blood, might shear and open and the blood might go in between the layers of the aorta.
This state is known as aortic dissection. So, if the breast starts to go, shearing the intima into the aorta, creating a new pathway, a new channel, There is going to be an insufficient blood supply for the rest of the body. So this is going to cause malperfusion of some of the organs, including the heart, the brain, the guts, the kidneys, everything, because instead of flowing to the normal channel, it will go into a blind area.
and that will make the malprofusion to happen. So this is an emergency with a very high rate of case, around 2%. But now, if the dissection happens in the ascending end, the RCC is so critical because the cerebral vein, the cerebral blood supply is going to be affected.
So, in a situation where the dissection happens and ascending in the arch, this is classified as type A. If the dissection happens after the lipsoid cleavage, this is called type B dissection. Type A dissection in general are critical and you have to intervene with surgery immediately. Type B dissections on the other hand can be managed with lowering the blood pressure.
and with a subsequent endovascular intervention. So they are not related to emergencies, but that's the thing. And the Arthritis type 1 is... What can happen without a doubt is that the blood can go and just create a hematoma, or we call it intramural hematoma, or it just can't go.
All these 3D are treated the same way.
So there is a shear in the intima and the blade goes into a wrong channel. So this is going to cause a malperfusion. So if it happens here, this is type 1 or type A. And if it happens after the arch, this is type B. This is what it looks like. So the blood has come out from the aorta and it sweats just about to rupture. Sometimes this thing ruptures.
at the emergency and patients die but so this is a common feature we can we see we can see blood has come out this discussion is going into the media and adventure of the author this is What you see, and this is about ruptures, so unless we intervene, patients are going to die. So, what do we do when this happens? We take out...
The voice memo has been edited to include proper punctuation. Implanted as new. And if the shielding goes all the way to the valve, the valve also should have to be replaced. But most of the time what we do is that we replace the ascending outer with a synthetic graft and we keep the quantity of blood flow through one channel to the rest of the body.
That's what auto-dissection is. In type B dissection, where it is below the arch or next to the subclavian artery, As I said, you can temporarily control the blood pressure with blood pressure medications and then you can put a stent. If this thing involves the entirety of the arch and the descending...
This is where I think another frozen trunk can be placed. This is replaced with a synthetic tube and then an expanding mesh. The framework will be extended to the normal Aorta and it will keep it open by sealing the holes. The last thing we are going to be talking about is the rhythm abnormalities. The most common rhythm abnormality in the heart is atrium fibrillation. This is fibrillation as you may know is uncoordinated.
myocardial contraction, in this case in the atrium. So in the myocardium, in the atrium, specially the left atrium is not contracting properly. It just figures like a bag of worms. That means it's not effective to pump blood. If it doesn't pump blood, blood is going to be stagnant, and the brain is going to be stagnant. It's going to clot. If it's going to clot, it might break at some point and will give, will embolize either to the brain or to the heart or to the mesentery, to the liver, to the kidneys.
So, the commonest thing that happens is that the clotted blood is going to go directly to the brain and give a stroke. So, there is a higher risk of stroke and this is because of this. and interest of dealing with atrial fibrillation. Commonly the atrial fibrillation arises from around the pulmonary veins. That's where it comes from.
When this takes over, they mapped it, and if you divide this thing, you can divide this way, this pathway, you can stop a traffic collision. This is the old Cox-Smith procedure. But there's a lot of things to do. You have to contain, you have to sue. So people came up with another way of dealing with this.
These are basically liquid nitrogen-based cryotherapy methods where you can freeze or ablate dust pathways around. The atrium is the primary vein or the intra-atrial right or left atrium with cryo-technic. So this is a nitrogen which is a liquid nitrogen which is going to freeze it.
different ways to do it. Yeah, that's my presentation for today. Do you have questions? Anything suggestion anything that sounds clear happy to answer the questions
Any questions? Anything that's not clear?