Transcription
I want to describe today a simple technique for difficult right heart cath, difficult because of a femoral access or because the patient has severe RV enlargement. In general, IG access is preferred to advance a swan catheter, whether in simple or difficult cases. However, IG access may not be possible in some cases, such as a patient with a short and large neck, or if you're performing a cath for MI and the patient goes into shock and you want to put a quick right heart cath, or some cath labs are not well set up to perform IG access. So you need to be familiar with all the techniques, and in order to do femoral right heart cath, there are traditionally three techniques. I will describe those; then I will describe my preferred technique, which has become my go-to technique whenever I suspect I will have any difficulty from a femoral access or even from an axis.
So the first technique from femoral access is to advance the catheter and try to hook the tip at the lateral RA wall. Then, as it hooks the lateral RA wall, you keep pushing it until it loops and goes into the PA. You may alternatively try to hook the catheter tip with the balloon inflated in one of the hepatic veins. And after it hooks a hepatic vein, you keep pushing the catheter until it creates a loop. Then you release the balloon to free the tip. Then you reinflate the balloon and keep pushing it to have eventually a shape similar to that one aiming into the PA. Hooking it in the hepatic vein would not work in somebody with severe heart failure and dilated hepatic veins, as when the catheter gets into a hepatic vein. If you keep pushing it, it will keep diving deeper into those hepatic veins rather than getting stuck and loop up. So this is the first technique. Hooking the lateral RA wall works in less than half the cases. In my experience, the swan catheter is flimsy and not torquable. So sometimes it goes wherever it wants to go, and that's the main limitation of that swan catheter.
The second technique is to advance the catheter at the base of the cardiac silhouette with a balloon inflated. Then do multiple 360° clockwise turns with back and forth push and pull until the catheter tip points superiorly and falls into the PA. Again, the catheter is difficult to torque. So we have to do multiple torques with a lot of push and pull, brief push and pulls, to transmit that torque. Alternatively, as an extension of that same technique, you can torque the catheter, try to make it point up and advance a swan wire, which is a 0.025 in wire or a 0.08 in wire, and use the catheter to direct the wire into the PA. Then, once the wire is deep in the PA, you try to track the catheter over it. This wire technique is helpful. One, it helps you get into the PA with the catheter. Two, it helps the catheter get deep in the PA without prolapsing out into the RV, cuz remember the catheter is too soft and may prolapse out in the RV and may create bends in the RA as you are trying to push it into the PA, especially in patients with dilated RV or tricuspid regurgitation. So, I like to use the wire, one to get me quicker into that PA, two to help me track deep into that PA. And I particularly like to use a stiff, or 18 in wire, and I give it a J tip at the end. And as I'm advancing the catheter into the PA, I pull on the wire. This will help the catheter track deeper. That pull while you're pushing the catheter. Also, the balloon may be kept inflated or deflated while tracking over the wire. I find that deflating it makes it easier in case of severe TR, in which case the flow of that TR may make the catheter sail backward if the balloon is inflated.
So those were the three techniques: hooking the lateral RA or hepatic vein, doing a clockwise torque, and especially doing clockwise torque with a wire, which used to be my preferred technique. And throughout all those techniques, remember that deep breathing increases flow in the PA and may make that catheter sail easier into the PA, especially deep breathing after valsalva or after cough, and keep in mind that in patients with a dilated right heart, it's not only difficult to get the catheter in the PA and prevent it from prolapsing out, it's more difficult to get it deep in the PA in order to wedge it, particularly that those patients tend to have dilated PA, and you need to get the catheter very distally into a distal PA branch in order to be able to wedge the catheter. So the wire is very handy in those cases, not just to get into the PA but to get deep into the PA, into a distal PA branch, to be able to wedge the catheter. And keep in mind another problem with the swan catheter is that it can only accommodate up to a 0.025 in wire. It cannot accommodate a heavily supportive wire.
So here's the fourth and my preferred technique for right cath from a femoral access. Whenever I expect difficulty or even a moderate degree of difficulty, that same technique may be applied for difficult swan advancement from an IG access, such as in patients with dilated right heart and severe TR or patients with multiple ICD leads or patients with a tricuspid annular ring. The most difficult right cath is always in patients with tricuspid annuloplasty. So anyway, that technique consists of advancing a five or a six French IM sharply bent catheter, and through it I advance a point or 35 in J-tip wire. Any standard J-tip wire may be used. So I advance the IM, then I make it point toward the RV. I advance the wire to the RV. Then I advance the catheter and I give it a clockwise torque, and it will point up. Unlike the swan catheter, this six French IM catheter transmits torque easily. So I torque it up. Then, as it's pointing up, I advance the 0.035 J wire deep into the PA and I track over it the IM catheter. Even if you have a dilated right heart and severe TR, that 0.035 inch deep wire usually provides enough support for tracking the catheter deeply into the PA without prolapse. And you want to position deeply in order to eventually get a wedge pressure. So after I get the catheter in deeply, I exchange the 0.035 in wire for a supportive 0.08 in wire with a J tip. You may also use a supportive 0.014 in wire, such as a grand slam or an iron man wire with a J tip. You position it deeply and over it you track the swan-ganz catheter. Afterward, I pull out the wire. I deflate the balloon. I flush the catheter. I obtain the PA pressure and the wedge pressure in this deep position. I obtain the PA oximetry, the thermodilution cardiac output. Then I obtain pullback pressures and oximetry if needed. And this technique is very straightforward even in difficult cases. It's actually a technique I use also when I'm trying to do thrombectomy for PE, uh, except instead of the IM catheter, I tend to use an angled pigtail catheter and I advance it into the RV and I clock it and make it point up, and through it I advance the wire. The reason I like to use a pigtail catheter when I'm trying to do thrombectomy is that a pigtail catheter is less likely to get stuck into the chordae, which would be a problem if you eventually try to advance a large sheath and large thrombectomy catheter. You don't want to disrupt those chordae.
And I want to describe a fifth technique that we should not forget about. Instead of doing a difficult femoral right heart cath, just try to do a brachial right heart cath through a brachial access; the swan-ganz catheter will eventually embrace a similar shape as an IG axis and it will aim toward the PA more easily than a femoral axis. Brachial vein access and placing a seven French slender sheath into a brachial vein is more readily possible in patients with dilated veins, such as those with severe heart failure. It's not possible in routine cases who don't have high right atrial pressure because those veins will be small. It will be difficult to access them and certainly difficult to place a large sheath in them without rupturing them. So in heart failure with high right atrial pressure, access for swan-ganz placement is a great technique, and it's best to access the basilic vein. So this is the brachial artery. It is surrounded by small deep brachial veins, but it's best to access the superficial medial basilic vein. This here is the basilic vein above the fascia. Compare it in size to those small brachial veins which are deep and small in size. So aim for that basilic vein. I do the access under ultrasound guidance and I choose the biggest vein, which is usually the basilic vein. Some operators have said that you know, ask the nurse to put an IV and over that IV exchange a 7 French sheath. I disagree with that because the nurse frequently puts the IV in a tributary of one of those superficial veins. If you try to put a seven French sheath in it, you will rupture it. Also, I like ultrasound guidance because I know to pick the largest vein, and I also know whether there is a large enough vein in those patients with high venous pressure that would allow me to place a seven French sheath. And when I advance this swan through the basilic vein, I usually advance it under fluoroscopy with a balloon deflated initially because the vein is not large enough to accommodate an inflated balloon. And once I reach the axillary vein, this is when I inflate the balloon. And regarding the prep, it's actually very easy. We usually use the same prep and the same drape as the right radial access. And we cut an additional square at the elbow level. You can stick in this position with the arm juxtaposed to the body. But since we stick very medially the basilic vein, sometimes it's hard to stick it in this position. So you may start with the arm abducted away from the body. Stick under ultrasound with the elbow covered by some sterile towels. Then, after the sheath is placed in, then we move the arm in to juxtapose it to the body and we place the radial drape with a cut at the elbow level.