May 11 Cardio Appt

Tyson went to Sick Kids yesterday for his regular cardiologist appointment, as well as an ECG, bloodwork, and chest x-rays. He has been fighting a cold for over a week, but his colour has remained good so I haven't been too concerned. His O2 sats yesterday were 82-84, about 1o percentage points lower than they were when he left the hospital after his stay there in March. I wasn't entirely surprised to see lower sats because he's had this cold. But Dr. McCrindle was not happy with that number at all, and he is proceeding with the next step of heart catheterization to close the fenestration (the "hole" created in his heart to relieve some of the pressure in his lungs) and MRI to assess the status of his left pulmonary veins. The cath will be an interventional heart procedure where they insert a catheter into the artery through either his groin or his neck, then threaded through the artery to his heart. They will place a tube or disk-like device into the fenestration to plug up the hole, so there will no longer be any mixing of blue and red blood. The MRI will give a good picture of his pulmonary veins and will be able to tell us how well the surgery in December worked and how it's holding up. For more on fenestration closure, see link below.

http://www.aboutkidshealth.ca/En/HealthAZ/TestsAndTreatments/Procedures/Pages/Fenestration-Closure-After-a-Fontan-Operation-in-the-Heart-Catheterization-Lab.aspx
The MRI will give a good picture of his pulmonary veins and will be able to tell us how well the sutureless repair worked and how it's holding up, or if the stenosis has reoccurred.

So we should be receiving a phone call sometime in the next few days (hopefully) with a date for his heart procedure. Dr M wants the cath done in the next 6 weeks. We are a little shocked to hear of this happening so soon, since most fenestration closures occur 6-12 months post-Fontan. Tyson is just 5 months post-op, so we really weren't thinking it would be pushed this quickly. But at the same time, we are eagerly anticipating news on the progression of the pulmonary vein stenosis.

Pulmonary vein stenosis is a very rare and serious condition in which there is an obstruction in the blood vessels that bring oxygen-rich blood from the lungs back to the heart. The stenosis occurs due to an abnormal thickening, and thus narrowing of the walls of the pulmonary veins. Since Tyson's pulmonary artery is also very small, his entire left lung is not doing very well at all. So currently Tyson has half of a functioning heart and only one good lung. The surgery in December included a Coles procedure, which is a sutureless repair of these veins, but we know from Dr VanArsdell his cardiovascular surgeon, that he didn't get the veins as wide open as he would have liked due to swelling in the heart.

I asked Dr McCrindle if they could just balloon or dilate the veins during his upcoming cath procedure. Dr M feels that this wouldn't be very effective because the stenosis will likely just reoccur. He figures that we should wait and see what we find on the cath before deciding what to do next.

I mentioned a study being done in Children's Hospital Boston on infants and children with pvs taking chemotherapy drugs to treat pvs. PVS mimics cancer, because unwanted cells continue to grow inside the veins. The study involves 2 chemo drugs with low side effects, that are well-tolerated by infants and children. One drug (Gleevac) is administered orally every day, the other (Avastin) is administered by IV bi-weekly. The chemo drugs would not reverse the already damaged effects of the PVS, but has been known to control the unwanted growth of cells, thus prolonging the child's life expectancy and quality of life. I asked Dr M if Tysonwould be a good candidate for this study. Dr M had never heard of it before and wanted to know more about it, so he gave me his email address, and I emailed him the link to the Boston hospital and the study being done. (see link below.)

http://www.childrenshospital.org/clinicalservices/Site683/mainpageS683P5.html

Yesterday I emailed Dr M the info and he already responded to me. He feels that Tyson may not be a good candidate for this study; his response is copied below:

The answer as to whether or not this applies to Tyson is very complex. This study assumes that pulmonary vein stenosis is caused by a build-up of cells lining the veins. In some patients, that is true. However, for patients with complicated heart disease, such as Tyson’s, there are other mechanisms which are more likely.

1. The lung arteries are small and underdeveloped, and hence the reduced flow into the lung and out of the lung means that the pulmonary veins are also small and underdeveloped (not likely to be helped by these meds).

2. The pulmonary veins are stretched by other structures or scarred from surgery (again, not likely to be helped by these meds).

I have had patients with the pulmonary vein “disease” which they are interested in, but I think it unlikely that Tyson has this kind of problem and would be unlikely to benefit from these meds (but would have all of the risks). I think we should wait and see what we find on the cath and MRI first, and then decide. I do know these people from Boston.

Dr. Brian McCrindle.

Anyway, Brian and I are both happy to hear that the cause of Tyson's pvs isn't 100% necessarily from an unwanted build-up of cells. We went down to the records department on Wednesday and received copies of ALL Tyson's reports from echos, ecgs, heart catheterizations, MRIs, chest x-rays, etc. I just really want to understand what exactly we're dealing with here. We learned that both his left pulmonary artery and his left pulmonary veins are about 1/3 of the size of his right artery and veins, and he has only 18% blood flow from this left lung. (This was as of his pre-Fontan cath report.) This is substantial. I know that the cardiologist is concerned about this, as he writes in his clinic reports to our family doctor. We also have copies of all those letters too, so we know exactly what we're having to deal with. Now we just have to wait and see what is going to be done about it.

Prayer Request: Please pray that Tyson's pulmonary veins are ok, that the surgery done to repair them was sufficient for him, that the function of his left lung will improve, and that there is no further re-stenosis in the veins. Please also pray for patience for Brian and me as we await his upcoming cath date. Here we go again :(