I promised in my last post to get into what a surgeon, Dr. Craig, could detail of Julian’s heart procedure. When he came in and sat down Dr. Craig took on a conversational attitude and prepped us in a matter of fact way. Some things he said made my mind race with worry. For more complicated surgeries like this… Hundreds of stitches… There are several risk factors.
I am a man on a high speed training hurtling along the tracks. I know that most likely this train takes me to somewhere safe and beautiful, but I also know that this train can derail at any moment and destroy everything. In my arms I clutch Julian with his big blue eyes and wide-eyed stare. I look up and see the big red handle of an emergency brake and I imagine wrapping my fingers firmly around it and yanking it down. With a blazing screech of sparks and a momentous jolt forward that nearly throws me to the floor the entire train comes to rest. I look around and breathe a scary exhausted breath and everything is fine. Except I am not doing that. Instead I am holding tightly onto Julian and praying that this train slows to a stop where I can slide open the door with one hand while I clutch Julian in my other and let in the warm brightness of a blue day.
Let’s start with what is physically wrong with Julian’s heart. He has what is called a transitional atrioventricular septal defect(AVSD), a cleft mitral valve, a patent foramen ovale and a perforated foramen. The most serious of these is the AVSD which consists of a large hole between his atria (#1 in pic) and a small hole between his ventricles (#2 in pic.) If you look at the image below the ventricles are the big chambers are on the bottom and the atria are the small chambers on the top. To repair the smaller ventricular part they will rely on stitches, to repair the larger atrial part they will use a piece of tissue from the pericardium (sac that contains the heart) or if there is not enough pericardial tissue they will use a synthetic patch that Julian’s living tissue will grow over. An AVSD allows blood to shunt the wrong direction across the heart. This causes mixing of oxygenated and unoxygenated blood, making Julian’s heart work harder. In fact one side of his heart is already enlarged from this extra work. On average his heart is beating 150,000 times a day and working harder with each beat.
The cleft mitral valve is very typical with AVSD’s. It is found on the left side of the heart and controls blood flow from the atrium to the ventricle. When the valve was forming prenatally, it typically has two pieces that merge together. In Julian’s case they did not complete the merge and the result is a Y-shape. This can result in blood flowing backwards through the heart. To fix this the surgeon uses a few stitches to sew the Y shut. Typically they try and fix the problem 90% as opposed to completely fix the problem. This is because if they go too far it can actually impinge blood flow from the left atria down into the left ventricle. Here is a little graphic to give you an idea.
A patent foramen ovale is a flap that allows blood to openly flow between a fetus’ left and right side of the heart and bypass the lungs. This is because the mother’s lungs are doing the work of oxygenating blood. As the fetus matures this flap seals shut and neatly separates the chambers of the heart. In Julian’s case the flap did not seal completely. The surgeon will stitch it shut. Julian also has a secondary problem which is that the flap has small holes throughout it. These need to be repaired individually with a series of minute stitches. They cannot tell from the heart ultrasound, but if the flap is too thin then stitching these holes shut will not be possible because the tissue could tear. In that case a patch may be used instead.
Now that you know what is wrong and how they will fix it I can get into the details of what the surgery entails. Julian will be sedated via a mask and then prepped for surgery. This includes insertion of a catheter, arm and leg iv’s, and a breathing tube through the nose. His body temperature will be lowered to slow blood flow. Next they make an incision down his sternum and use a bone saw to separate the sternum down the middle. Retractors are used to hold his chest cavity open to access the heart. If Julian’s thalamus is obstructing access to the heart then it will be removed. The thalamus is similar to your thyroid, but is temporary and goes away by adulthood anyways. His thalamus may be used to make medicine for many other people.
Next they will sever his aorta and transfer his blood flow to a heart lung machine. This machine will be responsible for keeping Julian alive until the surgeons can finish the repair of his heart. Next an incision is made in his left atrium through which the surgeons will do all their stitch work. Dr. Craig said that they expect to use hundreds of needles and make hundreds of stitches during the course of the surgery. Once the stitches are complete they will begin to warm Julian’s body back up and test the effectiveness of the repairs. If anything does not work quite correctly they will make the fixes now. Next Julian will be taken off the heart lung machine. Finally his breastbone will be wired together (no MRI’s for Julian) and his chest closed up.
There are three major dangers Julian faces from the operation. The first is infection. Typically 1-2% of patients will have some type of infection. Hopefully these are infections of the skin or subcutaneous fat layer as opposed to an infection in the heart.
The next major danger is stroke. The clamping of the aorta can release tissue into the bloodstream which can travel to the brain. Strokes can be anywhere from minor to terminal. Because Julian is so young and should not have built up material in his arteries, this should be of minimal risk.
The greatest problem that Julian faces is conduction problems which occurs in about 5% of surgeries. The heart’s beating is controlled by an electrical system that flows around Julian’s AVSD (the holes in his heart). As Dr. Emani seals these holes he must be careful not to pierce the conduction system while still creating an effective stitch. The electrical system is completely unidentifiable from surrounding tissue, so Dr. Emani will need to rely on his experience and skill to effectively place each stitch.