HLHS: Henry's Little Heart Sucks

Hypoplastic Left Heart Syndrome or HLHS is a bounty of bad news. It is one of the gravest heart defects where the structures on the left side of the heart are underdeveloped. There are differing levels to which the underdevelopment can occur but all HLHS children are, upon diagnosis, referred for cardio-thoracic surgery. You simply can’t live long with only part of your heart working.

I often referred to Cincinnati Children’s Hospital’s website (http://www.cincinnatichildrens.org/) to better understand Henry’s HLHS. To varying degrees, HLHS children have hearts that:

• Are missing or have a severely underdeveloped left ventricle. A ventricle is one of the heart’s pumping chambers. A normal heart has four chambers or “rooms:” two upstairs called the left and right atriums and two downstairs, the left and right ventricles. Right ventricles receive oxygen-poor (venous) blood and pump it to the lungs. The job of the left ventricle is to pump oxygen-rich (arterial) blood into the aorta. The aorta is the passageway way that moves this oxygen-rich blood from the left ventricle out to the body. When you look at diagrams of the heart, the blue parts are the ones moving or pumping oxygen- poor blood. The red parts are the ones for oxygen-rich blood.
  
• Both the aortic and mitral valves are underdeveloped, narrowed or completely closed. A heart valve is simply a doorway that allows the blood to flow in only one direction. The aortic valve pushes blood from the left ventricle into the aorta so that it can be sent out to the body. The mitral valve allows blood from the left atrium (upstairs) to be pushed into the left ventricle (downstairs). Then the mitral valve closes so that oxygen-poor blood does not flow back into the atrium. In HLHS cases, the mitral valve does not operate properly and oxygen-rich and oxygen poor blood mix. This means that some blood that needs to be sent to the lungs for more oxygen never arrives because it has flushed back into the atrium. Therefore, HLHS kids are always working doubly hard to get all the oxygenated blood they need. Their right ventricle goes into overdrive trying to compensate for the left by both pushing blood to the lungs and doing its’ “regular job” of receiving oxygen-poor blood from the body.
  
• HLHS kids also have septal defects. A septal defect is simply a “hole in the wall.” This means that blood can seep between the left and right sides for both the atriums and ventricles.

Or, to put it another way, HLHS is the worst highway construction you can ever imagine. Traffic tie-ups, dead-end routes and potholes. Blood simply cannot move the way it needs to bring oxygen to your child’s body. It is exhausting on both the heart and lungs that are desperately trying to compensate.

Henry’s HLHS was graded as “severe.” I find this comical because it’s not like a diagnosis of “mild HLHS” is something to cheer about. Henry’s left ventricle was essentially useless, just excess tissue flapping around in his chest. His aortic valve deteriorated rapidly because it was never normal to begin with and he had septal defects needing repair.

So, how in the hell do you repair all this? Currently, there are two medical routes parents and doctors consider. The first is a heart transplant and newborns and older children are successfully transplanted. But let me add caution to the term “successful.” A successful heart transplant means your child will be on anti-rejection medicines for the rest of their lives. These are also called immunosuppressants and they are the drugs needed so that the body will not reject the new organ. An immunosuppressant simply limits the immune system so that it won’t attack the new organ. Let me be clear: your child must take these every day, absolutely as directed because the body will naturally try to rid itself of what it considers “foreign matter” --- even if it is a heart. Anti-rejection meds bring forth a whole other set of medical issues. Heart transplanted children are more susceptible to hardening of their arteries, infections, drug reactions and certain types of cancer. You have to take precautions with live vaccines, their diets, other medications and use sunscreen obsessively. Finally, these days a “successful” heart transplant means to doctors that your child has a survival rate of 12 to 15 years.

I know that hardly sounds like a success and the first year after transplant is the most critical. Some children simply cannot survive with their new heart and the powerful drugs they must take. There can be some awful complications. But keep in mind that transplant teams do retransplantations because they believe they extend the time and quality of a child’s life. A retransplantation is simply when your child receives a second donated heart. Secondly, each year heart transplantation treatment improves. The surgical procedures are refined, drugs are improved and recovery treatments get better.

HLHS kids can also undergo a series of surgeries to compensate for their underdeveloped hearts. In Henry’s case, as in the case of many HLHS kids, we had this surgical series done and then still needed a transplant. That is because HLHS cannot be cured. Doctors still lack the capacity to rebuild such deformed hearts despite their heroic efforts. They can adjust things in your child’s heart to improve the blood flow but, to be blunt, you can’t build the Taj Mahal when all you have is a shack to start with.

HLHS surgery is usually done in three staged surgeries. In the first surgery, called the Norwood, doctors attempt to make the right ventricle take on the job of the deformed left ventricle: pumping blood back to the body through the aorta. At the same time, surgeons take a segment of the pulmonary artery (which takes blood from the heart to the lungs) and use it to rebuild the underdeveloped aorta. This way the blood flow to the body is increased. Lastly, surgeons build a new route from the right ventricle or directly off of an artery to send oxygen poor blood to the vessels heading to the lungs. The Norwood is considered the most difficult of the HLHS surgeries but it is critical to increasing the overall blood flow to the lungs and the rest of the body. This surgery is often done within weeks or months of birth.

The second surgery, the Glenn, is usually done within the first year of life. For the Fontan, the last HLHS surgery, doctors usually wait until the child is three or older. During the Glenn, the major blood vessels from the upper portions of the body (arms, chest and head) are cut away from the heart and attached directly to the pulmonary artery. This way all the oxygen-poor blood skips sloshing around in the heart and instead goes directly to the lungs for its oxygen. A successful Glenn procedure reduces some of the pumping stress on that right ventricle. The Fontan, is essentially the same surgery but for the lower half of the body.

Many HLHS children do great with these surgeries, coming out of the OR with oxygen rates (O2 sats) in the 90’s instead of the 75% they went in with. Nonetheless, your child still has a deformed heart. They may be much more active and need less meds but doctors will always want to poke around in there and see if anything else is deteriorating.

This is exactly what happened with Henry. We came out of the Fontan astonished to see Henry had O2 sats of 94%. Within two months, those were falling off. Within a year, Henry was back down in the 70’s with our cardiology team telling us that his deformed aorta was getting worse. “Successful” HLHS surgeries mean your child is functioning at the best level possible given that they only have one ventricle.

That being said, doctors estimate that some HLHS patients who have undergone these repairs will survive until middle adulthood. I know that, as a mother, that is still not enough time. But think how much heart surgery has improved in just our lifetime. Thirty years ago, HLHS was a death sentence for most babies and pediatric heart transplants were not faring well either. By the time our kids reach adolescence, there could be better surgical methods, better drugs and longer lives.

Again, I credit Cincinnati Children’s Hospital’s website in helping me better understand HLHS. It is a very complicated diagnosis and I don’t think anyone is expected to understand all that has gone wrong the first time they hear about it. Find a reputable website (or book or medical professional) and return to it often, learning about HLHS in steps.

HLHS is not kind. It requires multiple surgeries, long hospitalizations and powerful medicines that thin the blood, regulate heart beats and open up lung’s air sacs, amongst others. It is not a condition that can be cured but surgeons can do their best to compensate for your child’s birth defect. Some kids have the HLHS surgeries and improve greatly, others make it through long enough to go on the transplant list. Either way, it sucks.