Aligning US Agency Policies for Cardiovascular Devices Through the Breakthrough Devices Program.

Importance: The US Food and Drug Administration (FDA) and Centers for Medicare & Medicaid Services (CMS) have different statutory authorities; FDA evaluates safety and effectiveness for market authorization of medical devices while CMS determines whether coverage is "reasonable and necessary" for its beneficiaries. CMS has recently enacted policies automatically providing supplemental reimbursement for new, costly devices authorized after designation in FDA's Breakthrough Devices Program (BDP) and in June 2023 issued notice for a new Transitional Coverage for Emerging Technologies pathway, accelerating coverage for Breakthrough devices. Observations: Aiming to incentivize innovation, FDA awards Breakthrough designations early in device development to expedite market authorization and can accept greater uncertainty in benefit and risk, contingent on postmarket evidence generation. Since 2020, Breakthrough designation has effectively automatically qualified devices to receive supplemental Medicare reimbursement after CMS waived a long-standing requirement that devices demonstrate "substantial clinical improvement" for beneficiaries. Using publicly available information, 3 examples of cardiovascular devices illustrate that the BDP may allow for FDA authorization based on less rigorous evidence, such as single-arm trials focused on surrogate end points with short-term follow-up whose participants are often not representative of Medicare beneficiaries. In 1 case, Breakthrough designation allowed a 30% decrease in enrollment of a trial used to support approval. Initial positive findings for some devices have remained unverified, and in 1 case even partially nullified, by postmarket studies. Manufacturers have also used Breakthrough designations to set the price of devices to facilitate additional pass-through payments, leading to higher short-term and long-term costs to CMS and health care systems. Conclusions and Relevance: The BDP may qualify new, costly devices for higher and automatic Medicare reimbursement despite evidence not being representative of CMS beneficiaries and persistent uncertainty of benefit and risk. To ensure the best evidence is generated to inform clinical care, FDA could apply more selectivity to BDP eligibility, specify objective criteria for revoking Breakthrough designation when appropriate, and ensure timely postmarket evidence generation, whereas CMS could independently review clinical evidence, advise manufacturers about standards for coverage review, and make supplemental payments and long-term device reimbursement contingent on clinical outcome benefit and postmarket evidence generation.

US Food and Drug Administration Approval of Drugs Not Meeting Pivotal Trial Primary End Points, 2018-2021.

This cross-sectional study determines the frequency of and rationale for US Food and Drug Administration (FDA) approval of drugs not meeting pivotal trial primary efficacy end points.

Registration, publication, and outcome reporting among pivotal clinical trials that supported FDA approval of high-risk cardiovascular devices before and after FDAAA.

BACKGROUND: Selective registration, publication, and outcome reporting of clinical trials distort the primary clinical evidence that is available to patients and clinicians regarding the safety and efficacy of US Food and Drug Administration (FDA)-approved medical devices. The purpose of this study is to compare registration, publication, and outcome reporting among pivotal clinical trials that supported FDA approval of high-risk (class III) cardiovascular devices before and after the FDA Amendment Act (FDAAA) was enacted in 2007. METHODS: Using publicly available data from ClinicalTrials.gov , FDA summaries, and PubMed, we determined registration, publication, and reporting of findings for all pivotal clinical studies supporting FDA approval of new high-risk cardiovascular devices between 2005 and 2020, before and after FDAAA. For published studies, we compared both the primary efficacy outcome with the FDA's Premarket Approval (PMA) primary efficacy outcome and the published interpretation of findings with the FDA reviewer's interpretation (positive, equivocal, or negative). RESULTS: Between 2005 and 2020, the FDA approved 156 high-risk cardiovascular devices on the basis of 165 pivotal trials, 48 (29%) of which were categorized as pre-FDAAA and 117 (71%) as post-FDAAA. Post-FDAAA, pivotal clinical trials were more likely to be registered (115 of 117 (98%) vs 24 of 48 (50%); p < 0.001), to report results (98 of 117 (87%) vs 7 of 48 (15%); p < 0.001) on ClinicalTrials.gov , and to be published (100 or 117 (85%) vs 28 of 48 (58%); p < 0.001) in peer-reviewed literature when compared to pre-FDAAA. Among published trials, rates of concordant primary efficacy outcome reporting were not significantly different between pre-FDAAA trials and post-FDAAA trials (24 of 28 (86%) vs 96 of 100 (96%); p = 0.07), nor were rates of concordant trial interpretation (27 of 28 (96%) vs 93 of 100 (93%); p = 0.44). CONCLUSIONS: FDAAA was associated with increased registration, result reporting, and publication for trials supporting FDA approval of high-risk medical devices. Among published trials, rates of accurate primary efficacy outcome reporting and trial interpretation were high and no different post-FDAAA.

Cardiovascular function and structure are preserved despite induced ablation of BMP1-related proteinases.

INTRODUCTION: Bone morphogenetic protein 1 (BMP1) is part of an extracellular metalloproteinase family that biosynthetically processes procollagen molecules. BMP1- and tolloid-like (TLL1) proteinases mediate the cleavage of carboxyl peptides from procollagen molecules, which is a crucial step in fibrillar collagen synthesis. Ablating the genes that encode BMP1-related proteinases (Bmp1 and Tll1) post-natally results in brittle bones, periodontal defects, and thin skin in conditional knockout (BTKO) mice. Despite the importance of collagen to cardiovascular tissues and the adverse effects of Bmp1 and Tll1 ablation in other tissues, the impact of Bmp1 and Tll1 ablation on cardiovascular performance is unknown. Here, we investigated the role of Bmp1- and Tll1-ablation in cardiovascular tissues by examining ventricular and vascular structure and function in BTKO mice. METHODS: Ventricular and vascular structure and function were comprehensively quantified in BTKO mice (n=9) and in age- and sex-matched controls (n=9). Echocardiography, cardiac catheterization, and biaxial ex vivo arterial mechanical testing were performed to assess tissue function, and histological staining was used to measure collagen protein content. RESULTS: Bmp1- and Tll1-ablation resulted in maintained hemodynamics and cardiovascular function, preserved biaxial arterial compliance, and comparable ventricular and vascular collagen protein content. CONCLUSIONS: Maintained ventricular and vascular structure and function despite post-natal ablation of Bmp1 and Tll1 suggests that there is an as-yet unidentified compensatory mechanism in cardiovascular tissues. In addition, these findings suggest that proteinases derived from Bmp1 and Tll1 post-natally have less of an impact on cardiovascular tissues compared to skeletal, periodontal, and dermal tissues.

The pPSU Plasmids for Generating DNA Molecular Weight Markers.

Visualizing nucleic acids by gel electrophoresis is one of the most common techniques in molecular biology, and reference molecular weight markers or ladders are commonly used for size estimation. We have created the pPSU1 & pPSU2 pair of molecular weight marker plasmids which produce both 100 bp and 1 kb DNA ladders when digested with two common restriction enzymes. The 100 bp ladder fragments have been optimized to migrate appropriately on both agarose and native polyacrylamide, unlike many currently available DNA ladders. Sufficient plasmid DNA can be isolated from 100 ml E. coli cultures for the two plasmids to produce 100 bp or 1 kb ladders for 1000 gels. As such, the pPSU1 and pPSU2 plasmids provide reference fragments from 50 to 10000 bp at a fraction of the cost of commercial DNA ladders. The pPSU1 and pPSU2 plasmids are available without licensing restrictions to nonprofit academic users, affording freely available high-quality, low-cost molecular weight standards for molecular biology applications.

Pulmonary arterial strain- and remodeling-induced stiffening are differentiated in a chronic model of pulmonary hypertension.

Pulmonary hypertension (PH) is a debilitating vascular disease that leads to pulmonary artery (PA) stiffening, which is a predictor of patient mortality. During PH development, PA stiffening adversely affects right ventricular function. PA stiffening has been investigated through the arterial nonlinear elastic response during mechanical testing using a canine PH model. However, only circumferential properties were reported and in the absence of chronic PH-induced PA remodeling. Remodeling can alter arterial nonlinear elastic properties via chronic changes in extracellular matrix (ECM) content and geometry. Here, we used an established constitutive model to demonstrate and differentiate between strain-stiffening, which is due to nonlinear elasticity, and remodeling-induced stiffening, which is due to ECM and geometric changes, in a canine model of chronic thromboembolic PH (CTEPH). To do this, circumferential and axial tissue strips of large extralobar PAs from control and CTEPH tissues were tested in uniaxial tension, and data were fit to a phenomenological constitutive model. Strain-induced stiffening was evident from mechanical testing as nonlinear elasticity in both directions and computationally by a high correlation coefficient between the mechanical data and model (R2=0.89). Remodeling-induced stiffening was evident from a significant increase in the constitutive model stress parameter, which correlated with increased PA collagen content and decreased PA elastin content as measured histologically. The ability to differentiate between strain- and remodeling-induced stiffening in vivo may lead to tailored clinical treatments for PA stiffening in PH patients.

Perioperative Complications in Posterior Pharyngeal Flap Surgery: Review of the National Surgical Quality Improvement Program Pediatric (NSQIP-PEDS) Database.

BACKGROUND: Posterior pharyngeal flap (PPF) surgery is effective for treating velopharyngeal insufficiency but has historically been associated with risk of airway compromise. This study aims to identify risk factors for complications from and readmission after PPF using a national database. METHODS: Patients who underwent PPF surgery were selected from the 2012 American College of Surgeons National Surgical Quality Improvement Program Pediatric (NSQIP-PEDS) database. Patient characteristics, comorbidities, and complication/readmission data were analyzed. RESULTS: Among 225 study patients, 12 (5.3%) suffered perioperative complications. The most common complications were pulmonary in nature (5 patients, 2.2%), including prolonged postoperative mechanical ventilation (3 patients, 1.3%). Underlying asthma (P = .024) or any cardiac risk factor (P = .047) conveyed significant complication risk. Further, severe cardiac risk factors were associated with postoperative bleeding (P = .024). Readmission (4 patients, 1.7%) and reoperation (3 patients, 1.3%) occurred at mean intervals of 9 and 10 days after the original procedure. Seventy-nine patients (35%) were discharged postoperatively on an outpatient basis, and this subgroup included only one patient (1.2%) with a complication (P = .038). CONCLUSIONS: The overall perioperative complication rate for PPF surgery is low at 5.3%. Patients with underlying cardiac risk factors, severe American Society of Anesthesiologists Physical Status class, and asthma should prompt greater attention given their heightened risk profiles.