ObstetricalProcedures Under Ultrasound Guidance - HD

Introduction to Ultrasound-Guided Fetal Interventions

Thank you.

I'm gonna be talking about how we use ultrasound to guide interventions in the fetus.

And here you can see we're guiding a needle into the fetal abdomen where there's some ascites.

We do interventional procedures for diagnostic reasons and also to treat the fetus to try to improve the outcome.

There are two different kinds of situations where we would do an interventional procedure.

We might do a procedure to make a better diagnosis, such as amniocentesis to determine the karyotype of the fetus or chorionic villus sampling percutaneous umbilical blood sampling to diagnose chromosomes or to look for fetal anemia.

And we do it to drain some fetal fluid collections, such as the bladder to assess renal function.

But we also do procedures to try and improve the outcome for the procedure.

These include some situations where reduction amniocentesis will help improve the outcome.

Percutaneous umbilical vein cannulation for transfusion of the an anemic fetus, draining fluid collections in the fetus, and even shunting fluid to drain from the fetus, draining the urinary bladder or shunting the urinary bladder.

We'll also talk about the exit procedure.

We can talk a little bit about a cardiac twin ablation and then cardiac interventions.

Amniocentesis

Amniocentesis, this is when we put a needle into the amniotic cavity to drain fluid.

It's typically done after 15 weeks gestation, and from the fluid cells can be cultured to determine the karyotype of the fetus and also to look closely at the chromosomes for micro array analysis and specific gene identification.

Later in pregnancy, we would do amniocentesis to assess fetal lung maturity to look for chorioamnioitis to see if there's an infection or to relieve polyhydramnios.

These procedures are done under ultrasound guidance.

Here you can see two different amniocentesis being performed where a needle is passed through the maternal abdomen through the uterus into the amniotic cavity so that aspiration of fluid can be performed.

Here's a case where we did amnioinfusion.

This is bilateral renal agenesis with severe oligohydramnios.

The hope here was to try to put fluid around the fetus to allow it to develop and take the pressure off the fetal thorax.

So here we put a needle into the amniotic cavity, but instead of taking fluid out, we've now put fluid in.

So here you can see the needle tip is between the placenta and the fetus, and we are injecting fluid around this fetus.

Here we're injecting more fluid around this fetus to allow for enough fluid around the fetus.

And if we do this in this fetus, the hope is to allow, give this fetus enough of a buffer to allow for adequate pulmonary development until delivery.

Chorionic Villus Sampling

Chorionic villus sampling is done where we place a catheter into the placenta and try to, with a, with suction, remove chorionic villi.

This is done for genetic analysis of the fetus and can be done before amniocentesis at 10 to 14 weeks gestation.

And here they can culture the cells and get karyotype or microarray analysis or specific gene identification.

So here's a fetus who has a thickened nuchal translucency at 12 weeks gestation.

It measures 4.4 millimeters, which is abnormally thick, putting the fetus at high risk for chromosomal abnormality.

Under ultrasound guidance, we've performed chorionic villus sampling.

You can see that we've aligned the transducer.

So the needle is brought in at the fundus of the uterus.

This is a sagittal scan and passed into the placenta and the catheter.

Now it's a soft catheter coming out of the trocar that's taking pieces of the placenta, and those villi will be used to culture.

Percutaneous Umbilical Blood Sampling

To assess the fetal genetic material, we do sampling of the fetal blood, the blood, by doing percutaneous umbilical blood sampling.

The nice thing about this is we can put a needle into the umbilical vein so we don't have to puncture the fetus itself.

The reasons we do this is to obtain a sample of the fetal blood to measure the hematocrit and look for anemia or to do some specific lab tests such as liver function or thyroid function tests.

We also cannulate the umbilical vein in order to inject the fetus.

And we've done this, we do this to transfuse a fetus who is anemic, and you can also do this to inject medication into the fetus.

So here we have a pregnancy where the mom is RH sensitized.

The fetus was presumed to be anemic based on the middle cerebral artery, peak systolic velocity.

And so we're doing a percutaneous umbilical blood sampling for diagnosis.

And here we can see we've guided the needle through the maternal abdomen, the uterus, the placenta into the umbilical cord, right at the umbilical cord insertion into the placenta.

This is a very safe place because we haven't punctured the wall of the umbilical cord, so we won't have any seepage of blood into the amniotic fluid.

Here's another fetus who has iso immunization and fetal anemia.

You can see on the middle cerebral artery measurement that the peak systolic velocity is 77 centimeters per second, which is markedly elevated.

Fortunately in this case, this patient also had an anterior placenta with the umbilical cord insertion into the placenta right on the anterior wall.

So here we are passing the needle through that placenta into the umbilical cord here, and we are now transfusing this fetus with packed red blood cells because of the fetal anemia.

It's fun to do these because you can watch your success by watching along the umbilical vein and see the infusion of the red blood cells all along the umbilical vein.

And here you can see after the procedure, the peak systolic velocity has now returned in the normal range at 37 centimeters per second.

Draining Fluid Collections from the Fetus

There are some situations where we aspirate fluid collections from the fetus.

We might do this if the fetus has pleural effusions to improve the lung expansion.

We might do this if there's cystic lung masses to decompress the mass so that the lungs can expand.

And we might do this if there's a lot of ascites that's pressing up on the diaphragm that will then compress the lungs and prevent development or prevent breathing at birth.

Now, when a fetus has pleural effusions, overall the prognosis depends on the degree of pulmonary hypoplasia.

So if the fetus has had large pleural effusions for a long time during pregnancy, the lungs will not have a chance to develop properly.

But it also depends on the underlying cause of the pleural effusions and whether or not the pleural effusions are a component of hydrops or isolated.

If you look at all pleural effusions, over 10% will have aneuploidy.

So this is an important thing when counseling the patients and overall the outcome is somewhat poor.

50% will ultimately be normal, about 10% will die in utero, and 20% will have perinatal death or death after birth from the underlying problem that led to the pleural effusions.

And 30% will survive, but have other morbidities.

So there are treatments for these fetuses that can help improve the outcome.

We can do a thoracentesis to drain the fluid and sometimes that reverses the hydrops that we see.

But in all cases, it does allow for the lungs to expand if the fluid reaccumulates.

We can also do a thoraco amniotic shunt to allow for continued drainage of the fluid during pregnancy.

So here we have a fetus who has bilateral pleural effusions that ultimately became hydrops.

You can see very large pleural effusions on the right side.

The left side, the lungs are collapsed into the mediastinum.

This fetus also now has ascites.

And so we did drainages.

Here we can see we've got a needle passed into the amniotic fluid and then into the right thorax of the fetus.

And we're going to drain the fluid here.

And then the fetus rolled over a little bit and now we could drain the fluid from the left side.

And in this case, you can see we did a pretty good job.

This is right as we're taking the needle out, and you can see that we'd left a very small rim of fluid on the right side, small rim of fluid on the left side.

But look at this.

Three weeks later, now that ascites is all gone and we still only have trace pleural effusion.

So this was a successful thoracentesis bilateral that resolved, helped improve the hydrops.

But if the fluid reaccumulates, we sometimes have to put in a shunt, the shunts that we put in, put in a catheter with a pig tail.

So that one end is in the pleural space and the other end is in the amniotic cavity.

And this allows for continuous drainage of the pleural fluid permitting the lungs to continue to expand and grow as pregnancy progresses.

The other thing this does is it takes the pressure out of the thorax allowing for improved return of blood to the heart.

And this decreases the any hydrops that might develop.

These shunts have also been used to drain very large cystic masses in the chest, such as a macrocystic congenital pulmonary airway malformation.

So here's a fetus at 24 weeks gestation, where with a huge pleural effusion, displacing the heart over.

This is a left side displacing the heart over to the right side and compressing the lung of both sides.

So we did a thoracentesis notice, we're passing a needle into that left thorax.

The other thing I wanna point out to you is the inversion of the diaphragm.

So this clearly, this fluid has put a lot of pressure into that left thorax because it's inverting the diaphragm and pushed the heart way over to the right, we drained virtually all the fluid from the left chest.

You can see now the lungs, the chest is quite small because the lungs are so small, but you can see there's very little fluid left in the chest.

But unfortunately for this poor fetus, the fluid reaccumulated fairly quickly and even more than before.

Now we have a huge left pleural effusion here.

We see it filling the chest, there's barely room for the heart and the little nubbin of lung there.

And we now have a lot of ascites in the abdomen.

So it was decided to put a thoraco amniotic shunt into the fetus at that 27 week exam.

And here we are bringing a big trocar into that fluid inside the left chest.

This trocar has to be big enough that we can then pass the pigtail catheter.

Once it's in place, we take out the center of that sharp trocar and we pass then the pigtail catheter, one end of it here into the fluid space in the chest.

And then we pull back into the chest wall and then eventually into the amniotic space where we leave the other end of the pigtail catheter.

And here you can see the coil inside the left chest.

And here you can see the entire catheter now crossing the chest wall.

This was put in at 27 weeks gestation.

Here you can see it's in place with one end in the chest, one end in the amniotic cavity.

When we first put it in, we thought, oh my goodness, it's not working.

But as we watched in the next 20 to 30 minutes after this, the fluid began to decrease from inside the chest into the amniotic space.

It just took a while.

So here, eventually after the procedure, you can see that now there's much less fluid on the left side.

What was interesting to us is that there was actually some fluid also on the right side.

So this is a while after the procedure, but it was working.

Here it is, its 33 weeks gestation.

Now we don't see, we see almost no fluid in the left chest, but our catheter has held in place.

The lungs have had time to grow and expand.

And here's the baby at birth, you can see that there's almost no fluid inside that chest.

The lungs are expanded.

This baby was breathing on its own and our cute little catheter was still in place.

Abdominal Interventions

Sometimes we've had to put things into the fetal abdomen, such as a fetus who has anemia where we can't reach the umbilical vein, and so we can put red blood cells into the peritoneal cavity.

Fortunately, we don't have to do this very often.

Here's a fetus with twins who have immune hydrops.

So both fetuses are hydro because mom is RH sensitized.

So both fetuses are anemic.

And in this case, we transfuse the fetus directly into the peritoneal cavity.

So here you can see the catheter placed here where we can inject the red blood cells for twin one.

And here we are now in twin two injecting red blood cells and this fetuses, when you've injected these cells can resorb them and it can resolve their anemia.

Shunting for Posterior Urethral Valves

With posterior urethral valves, there's obstruction of urine outlet from the bladder, which leads to backup of the urine into the kidneys and ultimately can lead to renal dysplasia.

And then loss of renal function intervention should be considered after we've already assessed the residual renal function in the fetus.

And if the fetus still has adequate renal function, then putting a catheter in the bladder can maintain that renal function.

So what we do is we drain the bladder and then we wait 24 hours and 24 hours later we drain the bladder again to see if the fetus is able to concentrate electrolytes in the urine.

If that works, we may drain the bladder one more time to make sure the fetal kidneys are really working, and if they are, then it's worth considering putting a shunt in place.

So here's a fetus with posterior urethral valves.

You can see there's oligohydramnios around the fluid, just a little bit of fluid, very large urinary bladder.

And you can see the markedly dilated kidneys and the kidneys have echogenic cortices on both sides.

So that does suggest that there's renal dysplasia.

We're gonna make sure, so we're gonna test the urine in this fetus.

Initially we will stick a needle in the fetal bladder and drain it and just throw that urine away because we don't know when it was made.

But then the next day we can come back and drain it again to assess the function of the fetal kidneys.

And if there is adequate residual renal function, then we would put in a shunt to decompress the bladder and allow those kidneys to continue to grow and work because this will now decompress the kidneys and prevent further renal dysplasia.

There's a secondary benefit to putting in the catheter, and that is if you have a vesico amniotic shunt, you will replenish the amniotic fluid around the fetus, which permits growth of the fetal lungs to prevent pulmonary hypoplasia.

So here we have a fetus where we did put in a shunt from the bladder to the amniotic cavity.

You can see there's oligohydramnios around this fetus.

You can see that we've to improve our access, we've put fluid into the amniotic space so we can see what we're doing and increase the space.

So this is just saline into the amniotic cavity.

And here we are now passing the catheter through the maternal abdomen, uterine wall, placenta, amniotic cavity into the bladder of the fetus.

And once that's in place, we can then take out the center trocar and pass the catheter into the urinary bladder.

We then pull back the catheter into the amniotic space once the catheter is positioned in the bladder, and then we pull it back and leave that catheter in the amniotic cavity.

And this allows for continuous drainage.

EXIT Procedure

Now the next procedure I wanna talk about is a procedure that's not exactly an intrauterine procedure because it's a procedure that takes place during the course of delivery, and that's called an exit procedure.

And I didn't craft the name, but it's a great name and it means treatment on the way out or ex utero intrapartum treatment.

And so therefore, exit, and this is done in cases where there are hypoplastic lungs where the fetus may not be able to support respiration right at birth.

And so the exit procedure can be performed to put the fetus or the neonate onto ECMO directly from the uterus.

It's also done when there's an obstructed airway to allow for time for the surgeons to create an airway while the fetus is still connected to the placenta and then deliver the baby the rest of the way.

So this can be done with large diaphragmatic hernias.

Here's a large left diaphragmatic hernia.

These are the prenatal images.

You can see on a transverse view of the fetal thorax that the heart is pressed way over to the right side and the left chest is completely filled with abdominal contents.

So much so that the stomach has even crossed over the midline towards the right side, leaving a very small amount of right lung.

This is liver here, as you can see by the vessels in the chest.

So this fetus, it was determined that with such a low lung volume, this fetus would benefit from exit to ECMO, which is where the fetus is hooked up to catheters that take the blood from the fetal circulation oxygenate and return it to the baby.

So this is during the procedure and during the procedure, ultrasound plays a key role to make sure the umbilical vein doesn't get compressed because the fetus is still connected to the placenta.

So how does it work?

The cesarean delivery has begun.

The fetal chest and neck are delivered partway and the catheters are placed into the internal carotid artery and into the jugular vein.

And we monitor very closely with ultrasound.

Here you can see I got very upset during the course of this procedure because you can see that the fetus neonate, it was kind of halfway in between what the heart rate dropped to 39.

And I said to the guys, come on, hurry up, hurry up, hurry up.

So they did hurry up and here we are now with the baby out, just barely out.

And now the heart rate has returned to normal and the catheters are in place.

Using exit to ECMO has markedly improved the outcome of fetuses with diaphragmatic hernias as have the surgical techniques for these children.

And so the overall survival of these fetuses has improved greatly.

We also use the exit procedure for those with obstructed airways.

I'm gonna show you an example of a large neck teratoma that obstructed the airway.

But by delivering this fetus by exit, we were able to give the surgeons time to make a tracheotomy.

So here we are in utero.

This large neck teratoma was actually growing up from the mediastinum into the baby's mouth, can see the tongue is pushed out by this large tumor, completely obstructing the airway.

Here we are at delivery.

This is the fetus has only been delivered to the upper chest.

You can see the tumor blocking the airway with the tongue pushed out and the surgeons are trying to put in a tracheostomy.

What they didn't, they couldn't find the trachea though.

So I put my transducer on the neck and showed it was pushed way over to one side by the mass.

And then they put in the tracheostomy tube and then they had to resuscitate the baby because its baby had had obstructed lungs for so long.

There was a lot of fluid buildup in the lungs.

So while the fetus was still connected to the placenta, they had very vigorous resuscitation.

Here you can see they're starting to see a little air in the lung.

Here's a little more.

And eventually the lungs were aerated, as you can see here and here, and now the baby's breathing on its own.

And here it is.

The next day after the mass has been taken out, still has the tube inside the trachea.

Cardiac Interventions

So in the last little bit of time, I'm gonna talk about cardiac interventions.

These are interventions that we do on fetuses who have cardiac abnormalities that would benefit from in utero intervention.

Examples include a fetus with severe aortic stenosis developing hypoplastic left heart where we try to prevent the development of hypoplastic left heart.

Other times that we might do it is with hypoplastic left heart syndrome and a restricted atrial septum, or when there's pulmonic stenosis or atresia developing into hypoplastic right heart.

So our goal in fetuses with severe aortic stenosis is to try to open up the valve so that we can prevent hypoplastic left heart or even if it started to develop, to reverse it, to allow that left side of the heart to grow again and expand and minimize the degree of compromise of the left heart of the left ventricle.

With critical aortic stenosis, there's obstruction of flow through the heart that leads to damage of the left ventricular myocardium and poor growth of the left ventricle.

And if we can return the blood flow through the heart, we might be able to prevent hypoplastic left heart syndrome.

We position the fetus, we paralyze the fetus, and then we put a needle into the heart and then a wire across the valve and then a balloon across the valve and we blow it up.

Piece of cake.

So here we are, here is the fetus being anesthetized.

You can see we're passing a needle into the fetal buttocks and we're injecting an anesthetic agent for the fetus as well as a paralytic agent because we don't want the fetus to move and we don't wanna hurt the fetus while we're doing the procedure.

These are diagrams drawn by my husband Peter Dubay, showing how we do these procedures.

We use continuous ultrasound guidance to pass a catheter directly into the heart, and then through that catheter we pass the wire and then the balloon across the valve and blow it up.

So this of course is done under continuous ultrasound guidance because you have to keep changing your position and direction of the needle and you don't wanna miss.

So here you can see a 26 week fetus where we're guiding the needle into the amniotic cavity and then to the chest wall.

And this is the left ventricle we're trying to get into.

Notice that we can see the aorta, the aortic valve at all times.

And that's because it's not opening, it's closed, it has a teeny little hole in it.

And so that's critical aortic stenosis.

Here we are now partway into the chest and then into that left ventricle.

You can also see on this view how the left ventricle is not pumping as well as the right ventricle.

It's already got compromised contractility.

We then pull out the center of the needle.

Here's another one where we've gone into the left ventricle.

You can see the echogenic walls of that left ventricle.

So once we take the middle part of the needle out, now we can advance the wire.

So here you see we've got the trocar in place and we're advancing the wire.

We place it right beneath the valve and then we pass our wire across the valve.

These fetuses typically have a very small hole in the valve and we've figured out which wires work best to be carried through that small hole.

And then we position the balloon across the valve and we blow it up and then we get out of there as fast as we can.

So here's another case.

We've got the needle now placed inside the left ventricle.

Notice the echogenic walls of the left ventricle.

This is called endocardial fibroelastosis.

And it's a sign that there's already endocardial damage here, but these are ventricles we can save.

So we have the needle inside the left ventricle pointing towards the valve.

Here we are now angling it slightly more towards the valve to pass the needle across the aorta.

And here we have the balloon in place and the balloon being inflated across the valve.

And this is a 21 week fetus.

So this heart is the size of a small grape.

It's quite small.

As soon as we've taken that needle out, we take a look and see how we did.

Here's one that we did a good job here.

You can see there's nice flow coming out of that left ventricle.

And now we have antegrade flow in the arch.

So here's a diagram of what we're looking at.

Now when we do these procedures, one of the requirements is we only do these on fetuses where there's retrograde flow in the arch to start the procedure.

That's one of the indications.

So here we see a fetus, a comparison of the pre and the post-op findings.

You can see in the pre-op findings there's a small jet of flow across the aortic valve, but the whole valve is not open.

We can see reversed flow in the aortic arch when you see that double arch view here we have it immediately post-op.

We have a good jet of flow across the valve filling the width of the valve, which we did not do here.

And now we have antegrade flow in the arch already just after the procedure.

So these can be quite successful.

Atrial Septostomy for Hypoplastic Left Heart

Another indication for this procedure is when you have a hypoplastic left heart and the atrial septum closes.

As you know, normally there's a hole across the atrial septum called the foramen ovale.

But due to pressure changes with hypoplastic left heart, this can close.

This is a situation with very high perinatal mortality.

We can improve the situation for these neonates if we create channels across that septum so that the blood in utero can flow from the lungs and not back up into the lungs.

But also when the baby's born, there's a place for the oxygenated blood to go.

So here's a fetus with a hypoplastic left heart and restricted atrial septum.

Notice that the atrial septum is bulging here as we can see.

So this is because there is high pressure inside the left atrium, but no blood can get from the left atrium to the right atrium.

When we look at flow in the pulmonary veins in this fetus, it's to and fro.

There's no way for the blood flow to go.

Here's a different case, but the same findings, there's the atrial septum is completely closed and fibrotic.

This is a hypoplastic left heart.

This is how we do the procedure.

So we bring the needle into the right atrium in this case, and here we have the needle now in the right atrium.

And then in these cases we take the needle all the way across the atrial septum because we need to get across that atrial septum before we can begin to make holes in the septum which we do after we pull back.

So here now we've passed the needle in the trocar all the way across the septum.

Here's another one where we're gonna come in here, we're gonna pass the needle all the way across that septum, and then we leave the wire across and the balloon across and blow up the balloon across the septum to leave a hole across the atrial septum.

And we do this so that we can have in utero flow between the left atrium and the right atrium.

So blood now coming back from the lungs has a place to go because it's a hypoplastic left heart, it can't get out of the left side.

So we need this continuous flow from left to right.

We've even placed a stent across the septum to try to keep it open and bigger.

We do it the same way.

We bring the needle in across that closed off atrial septum.

We place the catheter and then the balloon with the stent on it across the septum and then we blow up the balloon that leaves the stent in place.

Here you can see the stent in position here you can see continuous flow across that stent from the left to the right.

And this does improve the outcome for these fetuses.

Overall, we've done over 200 procedures at the time that I submitted my syllabus here.

Most of what we've done have been aortic valve dilations, but we've also done atrial septostomies including some stents, pulmonary valve dilations, mitral valve dilations, and a few other cardiac procedures.

There is a learning curve here.

You can see that in the beginning about a quarter of our fetuses ended up in children with two ventricles.

And now about a half of our fetuses now are children that have a two ventricular circulation, which is our goal.

So this took improved expertise with the procedures as well as better entry criteria.

Thank you for your attention.