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Pulmonary Valvar Stenosis (PVS)
In PVS, we have an obstruction crusted by stenosis at one or more points from the R) ventricle to the pulmonary artery. These may be used by thickened muscle below the luminary valve, stenosis of the valve leaflets in the open position, or stenosis of the pulmonary artery above the valve, however the most common form of pulmonary stenosis is obstruction caused by the valve itself, called PVS.
Due to this obstruction, the R) ventricle is forced to work harder to pump blood through it, and thus will hypertrophic (ventricular muscle thickens) due to increased workload.
Signs & Symptoms
These children are often symptom free and in good health. Heart murmurs are the most common symptom detected in mild-to moderate degrees of stenosis that suggests a defect may be present.
However where the pulmonary valve is severely obstructed, we have impaired pulmonary flow to oxygenate blood and thus cyanotic babies, with blood shunting through the foramen ovale to allow blood mixing.
Older children with PVS will tire easily and become short of breath with activity.
Severe PVS can (but rarely) result in R) ventricular failure and sudden death.
Diagnosis
Heart murmurs are investigated, and along with this sound, there is often an associated click when the thickened valve snaps into an open position.
ECGs will often appear normal in mild pulmonary stenosis (PS), and in severe PS, the ECG may show R) ventricle enlargement and hypertrophy.
Echocardiograms evaluate PVS and diagnose specific location of the obstruction, with doppler studies to determine the degree of blockage.
Cardiac catheterisation may also be used to measure the degree of PS, however echocardiography is more commonly undertaken and rarely required.
It is important to note that diagnosis also involves excluding other issues that could be potentially associated with the PS, including an atrial and/or ventricular septal defect (see ASD or VSD for more info).
Treatment
mild PVS do not require treatment and can be healthy with normal lives. Mild PVS may develop into severe, and newborns that are critically ill with severe PS require emergency treatment via balloon dilation of the valve or surgical intervention.
Treatment involves first determining the type and value of the defect, followed by invasive intervention.
Balloon dilation valvuloplasty is undertaken through a catheter through the femoral artery up into the heart and does not require open heart surgery. However this can be very challenging in newborns and these babies can be very ill and unstable.
Open-heart surgery is undertaken for more complex valves where balloon dilation does not work.
Results & Outcomes
Results for balloon dilation and valvuloplasty for PS are very good, and hilt dilation cannot make an abnormal value become 'normal,' they are often still very successful.
Newborns and infants usually have a very good response to balloon dilation, however if the valve is underdeveloped, this is not the case.
5-10% of patients will have a reluctance of PS within 10 years of treatments and these patients may require a second dilation procedure.
Surgical treatment is also very good should they make it through the unstable period of time. However all children will require regular and long-term cardiology follow up to monitor for problems that may develop over time.
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