May 21, 2009 Through December 3, 2009:
Maren came home from the Rady's Children's Hospital on May 21, 2009. With the stent in her heart providing additional blood to the lungs, we started on the wait and see part of her recovery. The stent procedure is palliative. This means it alleviates the situation temporarily but is not a permanent cure. The purpose of the stent is to allow for (1) the baby to grow and gain some sturdiness, which is necessary for whatever surgeries come next, and (2) the right ventricle, which is too small (hypertrophic) and underdeveloped (hypoplastic) to grow and develop. During this time, the doctors can get a better picture of the attributes of the right ventricle. When the valve is blocked it is difficult to predict what the true characteristics of the right ventricle and the valves around it are. The heart is a muscle. When it is trying its hardest to pump blood out of the ventricle, and is unable to, the walls of the ventricle become thick and muscular. Further, the lack of blood flow impedes development, so that where there should be three parts to the ventricle, there could be just two. So a PAIVS baby will have a thick, small ventricle, which then lacks the ability to pump the volume of blood necessary.
However, with removal of the blockage at the pulmonary valve, the blood starts to flow, and the walls of the right ventricle literally can thin out as they relax. This increases the volume available in the ventricle, and it can heal. Still, there are limitations on how much the right ventricle can heal during this time and there is no way of knowing what the baby's ventricle will be capable of, except by waiting. Of course, in the interim, there is always the chance the flow could be insufficient - even with the stent - and Maren would not get enough oxygen, could turn blue, and we would head back to the NICU. Thankfully, this has not been the case. Maren has been as pink as can be, and has grown and developed beautifully during this time. The stent succeeded in bringing the oxygen levels in her blood to approximately 95% - which is basically normal.
In late June 2009 and again in late August 2009, the cardiologists conducted sedated echocardiograms to obtain information on how Maren's heart was progressing. While there is no way for the doctors to predict with certainty what would happen if the stent were blocked off (i.e. would Maren's heart pump enough blood) the doctors can measure the sizes of Maren's valves, measure the diameters of her arteries and veins, obtain pressure measurements, and eyeball the size of the right ventricle itself. This allows them to categorize and classify babies with PAIVS as either mild, moderate or severe. These classifications ultimately are used to select the heart treatment plan and what type of surgeries will occur in the future for the PAIVS baby, as follows:
Mild = 2 Ventricle repair: This means varying degrees and types of surgeries to augment the size and function of the right ventricle; the plan is to have a baby with 2 fully operating ventricles.
Moderate = 1.5 Ventricle Repair: This heart plan is premised on using the right ventricle to do just half of its job. Thus, half of the blue blood returning to the right ventricle is bi-passed via a shunt (called a Glenn Shunt or a Bi-Directional Cavopulmonary Shunt) such that it is piped directly into the lungs.
Severe = 1 Ventricle Repair: This heart plan occurs where the right ventricle is so atrophied it cannot do even half of its job. This repair requires the Glenn shunt surgery initially, and then later, another surgery called the Fontan operation, at which point all blue blood is bi-passed directly into the lungs.
At her discharge on May 21, 2009, Maren was considered moderate to severe. In late June she was solidly moderate, and in late August she was at the top end of moderate, on the edge of mild. Her improvement has led to some difficult decisions. First, it made it an option to perform a second pulmonary valvuloplasty (ballooning open the pulmonary valve). Since her original surgery on May 7, 2009, by late August, Maren's pulmonary valve was showing some obstruction to flow. It was not clear that another surgery of this type would produce benefits justifying the risks of the surgery. Ultimately however, based on the recommendation of the doctors, we went ahead and had this third surgery on October 23, 2009. Fortunately, it was successful. And again, because this is a catheter surgery (no knives), recovery is swift. We went in at 7am on a Friday and Maren was home around 3pm on a Saturday.
Second, Maren's improvement makes the decision less clear as to whether she is best suited for a 1.5 Ventricle repair or a 2 Ventricle repair. (And there is still an outside chance of a 1 ventricle repair ). There is no medical agreement on exactly where to draw the line between mild and moderate for PAIVS babies. The assessment is very difficult as to what defines mild, moderate and severe, and it is controversial and basically unknown whether better results will come from attempting two ventricle repairs or from performing 1.5 ventricle repairs in babies in Maren's spot. It all goes back to the uniqueness of each PAIVS baby. Under either scenario however, there is likely to be open chest surgery in connection with these repairs.
On December 14, 2009, Maren is scheduled for a sedated echocardiogram. Shortly thereafter, with those test results in hand, a decision likely will have to be made as to what heart plan and surgery is next. Maren's current circulation is not sustainable, as it mixes red and blue blood. Over time, this has other negative effects on the heart. The timetable for Maren's next surgery, to remove the stent and perform whatever other repairs may be required, is roughly anticipated to be January-March 2010.
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