For our other readers, Tetralogy of Fallot (ToF is a combination of four findings in the heart. These include a ventricular septal defect (VSD), an aorta that overrides the VSD, stenosis of the pulmonary valve and/or right ventricular outflow tract, and right ventricular hypertrophy, or thickening of the right ventricle. ToF with absent pulmonary valve is all of that PLUS the fact that the pulmonary valve doesn’t function adequately at all, and this starts in utero. What this means is that the blood flow going out to the lungs, which is flowing against high resistance in utero, typically goes forward and backward, or better described as a to-fro motion. This chronically abnormal blood flow occurring during cardiac development leads to severely dilated pulmonary arteries, with the dilation extending out into the lung tissue as the blood vessels branch. This arterial dilation can compress the airways, leading to airway obstruction that can lead to significant respiratory difficulties for these newborn babies. Apparently your son had a common complication associated with this, pneumothorax, or in his case, multiple pneumothoraces, in which the air pressure in the lungs blow holes in the lungs and they suddenly (or slowly) deflate.
For patients with ToF, long term outcomes after repair include problems with the pulmonary valve and its potential to leak. If it leaks a lot, it can cause a significant volume load on the right ventricle that put it at risk for heart rhythm abnormalities (some potentially lethal) as well as failure of the ability of the heart to squeeze appropriately. In general, there are also risks of general arrhythmias, dilation of the aorta, and neurodevelopmental problems, such as ADHD and abnormalities of executive function. Those patients w/ ToF/absent pulmonary valve are also at risk chronic airway problems to go with that as well as premature failure of the replacement pulmonary valve. As well, there is a higher incidence of a genetic disorder called DiGeorge syndrome, also known as 22q11 deletion (named for the chromosomal abnormality), which is associated with developmental, neurologic, psychiatric, vascular, and immune system abnormalities.
Unfortunately, there is not a lot of literature on long-term outcomes in these patients, as you have found. The only research that addresses this suggests that these patients have a higher likelihood of requiring pulmonary valve reoperation. That said, you also need to take into consideration the fact that medical literature from today report on patients who were operated on at least 1-2 decades ago, which may not have any bearing on more modern techniques used today. As well, I can’t discuss your son’s situation specifically, as I don’t have all the information that I would need to be able to assess prognosis, and there is a somewhat wide range of possibilities that can occur. I would surmise that since your son had a left pulmonary artery arising from the aorta, the increased flow across that artery may put him at risk for pulmonary hypertension (high blood pressure) across that artery. As well, since it had to be reimplanted into the pulmonary artery, it is likely at risk for obstruction at the implantation site, which it sounds like it already has done. This may be able to be managed with cardiac catheterization and balloon angioplasty with or without stent placement. The right pulmonary artery, which was chronically exposed to the abnormal blood flow, will likely be okay, though the large and small airways in the right lung may not be normal. The repeated pneumothoraces also puts his lungs at risk for scar tissue formation. The pulmonary valve probably will need multiple replacements through his lifetime, and each time that there is surgical entry of the chest, the risks significantly increase, due to scar tissue formation after the previous surgery. That said, there are new catheter-delivered bovine jugular valves mounted on stents that can be placed in the pulmonary artery that may reduce the need for one or more surgeries. I don’t know if he has DiGeorge syndrome, which probably shortens his life expectancy. Overall, if he does not have DiGeorge syndrome, if his cardiac issues can be managed with cardiac catheterization and minimal surgeries, and if his lung function is otherwise normal, there is a fair chance that he should get AT LEAST to middle age, if not more. What is most important here is that he have lifelong follow-up and surveillance by a pediatric cardiologist (and, eventually, an adult congenital heart disease specialist) who not only is familiar with these problems and complications, but also will have access to both the monitoring modalities that he will need as well as the facilities and personnel to be able to intervene, as needed.
Dear Dr. Boris,
Thank you so much for your response. It was kind of what I expected to hear. My son is doing very well both cardiac and respiratory. He did have a balloon angioplasty without stenting to the left pulmonary artery 6 months after his repair. It did help a little, but not as much as was hoped. An MRI approx. 2 yrs ago showed that there is moderate narrowing at the insertion site to the main pulmonary artery, his cardiologist feels that no intervention is needed at this time. We are continuing to follow that as well as his yearly echos, EKG's. He does not have DiGeorge syndrome and has had no real issues with his lungs after his inital repair. So, it seems as though he is doing well from a "lung standpoint." I haven't spoke to his current cardiologist about his prognosis....to get his opinion, but I will at his next yearly appointment. Thanks again for taking the time to address my question and explain everything in detail. I appreciate it. Take care.