Research methodology and practical issues relating to the conduct of a medical device registry.

BACKGROUND The postmarket research goal is to assess "generalizability" or "external validity" to see if the early results of clinical trials with investigational devices are reproducible in everyday practice in the real world and the longer term. Registries have an important but ambivalent role in achieving this goal. METHODS Although registries are common, in practice they follow the regulatory processes that appear designed primarily for pharmaceutical clinical trials and confirmatory studies. We review the literature to assess different definitions and the role of registries in the hierarchy of scientific evidence. We analyze common characteristics affecting registry design, implementation, and governance as well as safety reporting and off-label use while describing the experience of setting up an international, prospective registry for an endovascular device used to treat abdominal aortic aneurysms. RESULTS Key areas in which to distinguish registries from trials are as follows: eligibility, setting (patients and institutions), device configurations and iterations, the use of design and quality "spaces," a focus on systematic quality checks (rather than source data monitoring), open-ended follow-up, flexibility in the definition of end points and sample sizes, data sharing, and publishing commitments. CONCLUSION Both clinical trials and registries are essential and complementary research methods and the strengths and weaknesses of each need to be recognized. The specific characteristics of registry research deserve to be acknowledged and safeguarded in the regulations governing clinical investigations with medical devices

ZILVERPASS Study: ZILVER PTX Stent vs. Bypass Surgery in Femoropopliteal Lesions, 3 year results and economic analysis.

BACKGROUND To report the 3-year safety and effectiveness results of a multicenter, prospective, randomized controlled trial comparing the ZILVER PTX paclitaxel-eluting stent to surgical bypass and to conduct a health economic analysis up to 3-year follow-up of the two treatment modalities. METHODS This is a study in symptomatic TransAtlantic Inter-Society Consensus (TASC) C and D femoropopliteal lesions comparing endovascular ZILVER PTX stenting vs. surgical bypass surgery using a prosthetic graft (ClinicalTrials.gov identifier NCT01952457). Between October 2013 and July 2017, 220 patients (mean age 68.6±10.5 years; 159 men) were enrolled and randomized to the ZILVER PTX treatment group (113, 51.40%) or the bypass treatment group (107, 48.60%). One of the secondary outcomes was primary patency at 3-year, defined as no evidence of binary restenosis or occlusion within the target lesion or bypass graft based on a duplex ultrasound peak systolic velocity ratio <2.4 and no clinically-driven target lesion revascularization (TLR) in endovascular cases or reintervention to restore flow in the bypass. An economic analysis was conducted to analyze the cost differences between ZILVER PTX and bypass, which shows the perspective of the public authority/organization that pays for healthcare in the two countries (payor), Germany and USA. RESULTS The 3-year primary patency rate was 53.30% (95% CI 61.40% to 45.20%) for the ZILVER PTX group vs. 58.20% (95% CI 67.10% to 49.30%) for the bypass arm (P=0.9721). Freedom from TLR at 3-year was 62.80% (95% CI 72.60% to 53%) for the ZILVER PTX group vs. 65.30% (95% CI 75.40% to 55.20%) for the bypass group (P=0.635). There was also no significant difference (P=0.358) in survival rate at 3-year between the ZILVER PTX group 78.50%, (95% CI to 87.70% to 69.30%) and the bypass group 87.40% (95% CI 97.6% to 77.2%). None of the deaths was categorized as related to the procedure or device. The economic analysis, taking into account procedural-, hospitalization- and reintervention costs, showed a clear cost-benefit for Zilver PTX in both investigated countries up to 3-year follow-up: Germany (Bypass €9446 per patient versus ZILVER PTX €5755) and USA (Bypass $26,373 per patient versus ZILVER PTX$19,186). CONCLUSIONS The non-inferior safety and effectiveness results of the ZILVER PTX stent were associated with lower costs for the payer and confirmed that ZILVER PTX stent treatment can be considered as a valid alternative for bypass surgery in long and complex femoropopliteal lesions