Project Objective:

This protocol aims to determine whether data capture of device utilization in a Pediatric Cardiac Catheterization Laboratory is possible across multiple different institutions. The device of interest is the range of Cook Formula 418® Pre-Mounted Stents. While searching for the devise of interest, we will characterize all stent devise use at participating sites. This pilot study is designed to begin to devise a global approach which will ultimately be applied across institutions and networks.

Project Abstract:

This proposal aims to determine if National Evaluation System for health Technology Coordinating Center (NESTcc) could adequately capture a specific stent implantation in pulmonary arteries and systemic veins during congenital heart disease therapy. The medical device of interest is the range of Cook Formula 418® Pre-Mounted Stents, which are currently used “off-label” in this population. These stents are of particular interest in the pediatric age as they are pre-mounted, have low profile, excellent radial strength and expandability. Successful implantation and use surveillance could provide the impetus for more robust outcome assessment, and subsequent possible label expansion. In addition, we will characterize the range of pediatric stent use at participating PEDSnet sites and develop a scalable approach to investigating pediatric device use in PCORnet networks.

Specific Aims and Significance:

Formal regulatory (United States Food and Drug Administration -USFDA) approval for devices used in congenital heart disease is rare, and the majority are used “off-label” after adult approval. The lack of formal regulatory authorization, and the potential cost of separate pediatric studies has undermined industry development, and constrained therapies in the pediatric space. Other than single center and limited registry adverse event data, actual implant prevalence and subsequent long-term surveillance has been rare. Stent therapy for the primary or secondary treatment of vascular stenosis in pediatric age patients provides an illuminating example. While much work has been accomplished in obtaining USFDA approval for covered stent use in the treatment of aortic coarctation, no such work has been performed for stent utilization in pulmonary arteries and large systemic veins. The available devices used in this space are approved for peripheral vascular, renal or biliary indications in adults, and come from multiple different vendors. Each has different properties (such as metallic constitution, radial strength, fracturability (with over distension), etc.), and are either hand-mounted or pre-loaded on balloons. 

Only recently has a new range of pre-mounted stents, more suitable for pediatric-aged patients, and with the ability to dilate up to nominal adult size been introduced in the US. The suitability of this range of stents (Cook Formula 418® Renal Balloon Expandable Stent (Cook Medical, Bloomington, In.)) results from their low profile (thus able to pass through small vessel sheath size), excellent radial strength, and in the larger available sizes, ability to dilate up to adult dimension when necessary. The pre-mounted packaged presentation of the stent / balloon complex also adds significantly to the ease and presumed safety of use. Apart from occasional single center publications, the widespread use of this device in the pediatric and congenital heart disease population is uncertain, and thus adequate follow up from a post-market perspective is uncertain. This proposal would allow prevalence information (how many stents are implanted in pulmonary arteries and systemic veins to treat congenital heart disease) to be collected across a consortium of multiple institutions. If shown to be successful in accurately capturing the prevalence of these implantations, subsequent study iterations could address the development and necessity of consistent cross-institutional follow-up protocols, and accumulation of robust clinical outcomes data. This could in time serve as the basis for a label expansion application. System protocols and conventions already established by NESTcc would serve as an ideal framework in the initial real-time phase of this project.

Aims:

a. Determine the total number of implantations of Cook Formula 418® stents during congenital and pediatric cardiac catheterization procedures during a one year period (with quarterly data analysis).

b. Characterize the range of types of pediatric stent types used by a sample of pediatric hospitals

c. Compile a data set that would comprising device specific attributes (device length / diameter) and relevant patient demographic information.

d. Associate specific implantation location with cross-reference of the Unique Device Identifier (UDI) and procedure specific Current Procedural Terminology (CPT) codes. The UDI is a device specific code created under direction of the FDA Amendments Act of 2007 and FDA Safety and Innovation Act of 2012. 

e. Compile patient demographics to include age, weight, height, body surface area and diagnosis.

Significance:

Percutaneous stent therapy for vascular stenosis is an established cornerstone in congenital heart disease. Since stent therapy was first reported in 1986 in adult coronary arteries by Peul and Sigwart, and in pulmonary arteries in children in 1991 by O’Laughlin and colleagues, much progress has been made in this field. However, the majority of the work has been in the adult arena, with pediatric applications receiving “orphan” status, or in some cases, none at all. The major regulatory authorities have focused primarily on adult outcomes, and owing to the almost universal application of stents for coronary artery disease, little work has been completed in a systematic manner in the pulmonary arteries and systemic veins. In addition, commercial entities and device manufacturers have focused their attention on major sources of income, again assigning the pediatric population to a secondary status. The pathophysiology of adult vascular stenosis is mostly related to coronary artery disease, while in pediatrics, congenital stenosis or post-surgical vascular compromise is more frequent. 

Of much greater importance though, is the reality that after adult stent implantation, required redilation is infrequent (since subsequent restenosis is likely from progression of in-stent stenosis and progression of underlying coronary artery disease), while in children, growth and development have to be taken into account when placing intra-vascular stents. It is obvious to pediatric practitioners that any stent placed should be able to be expanded ultimately to an adult size (during subsequent cardiac catheterization), thus obviating the need for further surgical intervention in many cases. That same pre-requisite (ability to dilate to adult size and maintain radial integrity), also drives many of the fundamental structural features of implantable stents in children. That being said, the shaft size should be as small as possible (to incur little if any vascular damage), the intrinsic materials used should be non-leachable, the expanded radial strength should be maximized, and endothelial vascular reactions should be minimal. It is in following patients after such vascular implantations that the impact on pathology and chronic stent outcomes (over multiple years) is not clearly understood. Hence the significance of this pilot. If successful in demonstrating that “automated device tracking” across multiple institutions using the Electronic Medical Record (EMR) is possible and accurate, this study could in turn lay the groundwork for substantial and extensive long-term follow up of this group of patients. Needless to say, cumulative outcome data in regard to “off-label” use of an USFDA approved device could ultimately be of use for a label expansion application.