References: Dr. med. Gregor J. Krings MD Pediatric Cardiology UMSC Utrecht / Netherlands
Innovations on a newly developed Cobalt Chromium XL Stent PTFE covered and non-covered.
In the daily practise of an interventional paediatric cardiologist we often miss adequate material to treat complex lesions in vessel stenosis. There is a need for stents capable of large diameters and still being low-profile to treat our patients in childhood with the option to redilate at adult age. The number of patients with congenital heart disease is relatively low compared to the patient population of coronary or peripheral disease. The industry is focussed on the market of adult cardiology rather than on the small paediatric and congenital market. However treating sick children with congenital heart disease is an important field in paediatrics. The major goal is to achieve a higher quality of life for each individual.
The development of special diagnostic catheters, wires, balloons, all kinds of implantable devices and most of all stents is a cumbersome and very expensive venture for a company and is not paid off well under pure economical aspects. AndraTec Germany however has decided to develop dedicated stents for the paediatric cardiologists. We are very happy to see a company – despite of all these difficulties – listening to our needs. They decided to walk this cumbersome road and developed new types of stent devices that can be used in the paediatric interventional field with a huge range of diameters achievable by re-dilatation up to adult size.
In a technology outline we want to report on the newly developed Optimus PTFE covered and Optimus non-covered Cobalt Chromium stent with hybrid cell design (AndraTec Germany).
A dedicated team of pediatric cardiologists and a masterpiece in stent engineering of AndraTec engineers has managed to build these types of devices. This new and highly innovative company has put their focus on our needs integrating the development of these stent devices into their portfolio – being aware of the small-scale market for a small group of patients.
One of our main substrates in pediatric and adult congenital cardiology is the optimal treatment of vessel stenosis. Implanting stents in small children does demand small delivery sheath to take the femoral vessel dimensions into account. During growth the implanted low-profile stents need to be re- dilated. The ideal range of a stent diameter for pulmonary artery trunk, side branches or aortic stenosis starts at 8 or 10 mm when implanted in early childhood and ends at around 18 to 28 mm and more when being re-dilated at adult age. High radial strength without being to rigid, little shortening, a hybrid-cell design and especially a trustable PTFE covering are the major characteristics for our ideal stent. Different stents as Palmaz or Genesis, Jo-Stent, Valeo, ev3 Mega / Max LD, Formula and the large CP stent were developed and each was a milestone offering a wider range of treatment.
However up to now a low-profile stent with hybrid-cell design, a maximum diameter above 20mm and a covered version with a truly sealing surface and acceptable shortening did not exist. So far the treatment of stenosis by stentimplantation in the pulmonary arteries, the aorta, the upper caval vein or conduits is challenging and not always sufficient. Typical indications for covered and non-covered stents capable of large diameters are: I. the native or post operative aortic coarctation (Fig. 1), II. prestenting of the right ventricular outflow tract in PPVI procedures (Fig. 2/3) III. pulmonary artery stenosis (Fig. 4)
(Fig. 1-4)
In adult patients however large balloon expanding stents are used mainly in the Aorta or to assist in the treatment of type I endoleaks after AAA stent graft implantation as well as in oncology patients with vena cava superior syndrome / vena cava inferior syndrome.
The technical requirements for these type of stents very high.
Ideally these stents should be designed :
– with a hybrid cell structure that can provide little shortening and high radial force but also remain some flexibility to conform to the anatomy;
– to enable large expanding diameters that can cover a brad range of the large vessel are needed and
– with a trustable, well fixed and non-perforating PTFE covering to take care of possible dissection or rupture which can occur during aggressive dilatation in these type of lesions.
– and with a low profile to allow initial implantation through small sheath sizes.
The newly developed and highly innovative Optimus Covered and Bare stent (AndraTec Germany) seem to overcome the main issues of the current XL stents when treating these lesions in an optimal manner.
The stent has a hybrid cell design so it anchors ideally in the vessel to provide a secure landingzone for PPVI procedure. Being expandable up to 39mm the Optimus stent has the widest expansion range of all existing stent types. The 3 different stent dimensions / design L/XL/XXL provide an optimal high radial force with little shortening < 20% for the main diameters.
The covered version does extent the indication and use of the Optimus stent. It offers the security we need when treating high-risk stenosis in the great arteries. The double-sided PTFE covering (Optimus CVS) (Fig. 5) does follow the huge achievable diameters without rupturing. Aneurysm can be sealed safely. Calcified homograft’s, severe great artery stenosis being known to potentially rupture can be treated adequately.
Cobalt Chromium as a stent material will provide an additional element for radial force but with minimizing the amount of implanted material.
(Fig. 5) (Fig. 6-8)
With Regards to Dr. Stephen Brown & Dr. Ebrahim Hoosen from South Africa we have received this great case where the Optimus Covered stent and Optimus Bare Stent have been successfully implanted in the main pulmonary artery to create the optimal landingzone for pulmonary valve implantation. (Fig. 6-8)
Resume:
The new and highly innovative Optimus Stent & Optimus CVS from AndraTec Germany have the ability to change the interventional pediatric treatment options.
Conflict of Interests
The authors declare they have no potential conflict of interests or any financial relations.
© AndraTec International • June 2015
