Definition and overview
A percutaneous transcatheter IV stent treatment is a procedure used to replace a damaged or diseased pulmonary valve with an artificial valve (such as the Melody valve). This is a minimally invasive surgical treatment for a disease that will otherwise require open-heart surgical repair. While a Melody valve procedure does not completely rule out the need for open-heart surgery, it can delay the need for it for as long as possible and reduce the number of surgeries that patients with heart defects have to go through during their lifetime.
A Melody heart valve is a specially designed artificial heart valve made from a cow’s jugular vein. The vein is sewn into a small metal framework to create a pulmonary valve replica. It is produced by a company called Medtronic and comes with the Medtronic Ensemble delivery system that includes a delivery sheath made of polytetrafluoroethylene (covers the valve during delivery) and a balloon-in-balloon (BIB) catheter. The balloon is available in three sizes, namely 18mm, 20mm, and 22mm.
The Melody valve is not the only available artificial valve, but it is the most promising if previous treatment results are to be considered. The main advantage of using a Melody transcatheter pulmonary valve lies in its delivery system, wherein it is delivered to the heart via a catheter. The procedure to deliver the valve does not require open-heart surgery and can be performed even while the heart is beating. Also, the Melody valve is less bulky and comes with a retractable sheath that is very useful in protecting the valve prior to deployment. Perhaps, its only disadvantage is its size limitation as it is only available in a single 22mm size, whereas other types of artificial valves offer other sizes up to 26mm for patients with larger conduits.
Who Should Undergo and Expected Results
A percutaneous transcatheter of IV stent procedure is highly recommended for patients with damaged pulmonary valves and congenital heart defects, including previously untreatable ones such as truncus arteriosus. A similar procedure, called transcatheter mitral valve replacement, uses the same non-invasive delivery technique to replace a damaged mitral valve.
When the pulmonary valve is damaged beyond repair, blood can leak back into the heart’s chamber. This disrupts the normal flow of blood through the heart, and patients will benefit from having the condition treated promptly.
After a transcatheter Melody valve replacement, it is expected that the normal blood flow to the heart will be restored. Other symptoms caused by a damaged heart valve should also be relieved. These may include arrhythmias, regurgitation, and outflow obstruction. Short to medium term outcomes of a pulmonary valve replacement via catheter are quite good, with valves working properly and a low morbidity rating.
How is the Procedure Performed?
A transcatheter of IV stent percutaneous treatment is performed without a large surgical incision. This technique reduces post-surgical pain, recovery time, and risk of complications.
Transcatheter pulmonary valve replacement surgery is performed under general anaesthesia. This means that patients are asleep throughout the entire duration of the procedure, and will not feel any pain.
During the procedure, the artificial Melody valve or TPV valve is compressed inside a thin hollow tube called a catheter. The catheter is then inserted into a vein and guided slowly towards the heart. The entry point for the catheter is usually the leg. Since the catheter is very thin, it only requires a small access site.
Once the catheter is in the right place, the balloon is inflated to deliver the valve to its proper position. Once in place, the Melody valve will expand and begin to facilitate proper blood flow from the right ventricle going to the lungs. Once it takes over the damaged pulmonary valve, the catheter is removed.
After the transcatheter of IV stent for percutaneous delivery of a Melody valve, the doctor will perform certain tests to ensure that the artificial valve is working properly and is taking over all the functions of the pulmonary valve. Once the procedure is deemed successful, the surgeon will close the access site.
Patients are then brought to a recovery room until the effects of anaesthesia wear off. Once the patient is awake, they can safely be transferred to a regular hospital room. Although it is minimally invasive, it is still a sensitive procedure as it involves the heart. For this reason, patients are still often required to stay in the hospital overnight but are usually allowed to go home the day after the procedure.
Due to the less invasive nature of the procedure, patients can return to their normal activities two days after as long as they continue to take the prescribed medications and follow their doctors’ care instructions.
Possible Risks and Complications
A transcatheter pulmonary valve replacement is not without risks, but it does reduce the severe surgical risks of open-heart surgery, such as pain and bleeding. Nevertheless, patients are still at risk of developing an infection related to their artificial heart valve. As such, after the procedure, patients are advised to watch out for an unexplained and prolonged fever. Other potential risks and complications of an artificial pulmonary heart valve include calcification and scar formation. These complications may lead to valve dysfunction, in which case patients may be required to undergo the procedure again.
To prevent potential risks, patients should keep their after-care appointments, which are intended to keep the Melody valve working properly. They should also inform future care providers, such as doctors and dentists, that they have an artificial Melody valve in place.
“Melody Transcatheter Pulmonary Valve (TPV) Therapy.” Medtronic. http://www.medtronic.com/melody/patient/therapy.html
Jones TK, Rome JJ, Armstrong AK, Berger F, Hellenbrand WE, Cabalka AK, Benson LN, et al. “Transcatheter pulmonary valve replacement reduces tricuspid regurgitation in patients with right ventricular volume/pressure overload.” October 2016. Journal of the American College of Cardiology. Volume 68 Issue 14. http://www.onlinejacc.org/content/68/14/1525
Ghawi H, Kenny D, Hijazi ZM. “Transcatheter Pulmonary valve replacement.” Cardiol Ther. 2012 Dec; 1(1): 5. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4107445/