Regulatory strategies for early device development and approval.

The development of new technology to treat unmet clinical needs is an important component of modern cardiovascular disease. The need for this has been emphasized in the past several years beginning with the Food and Drug Administration (FDA) guidance document on Early Feasibility Studies in 2012 and then the 21st Century Cures legislation. A number of steps need to be considered in this process by the stakeholders involved including physician innovators and scientists, professional societies such as Society for Cardiovascular Angiography & Interventions, regulatory agencies, and medical device companies. This article focuses on the early iterative steps required to optimize the process and achieve the goal of timely efficient innovation and device development in cardiovascular disease.

Conformal Left Atrial Appendage Seal Device for Left Atrial Appendage Closure: First Clinical Use.

OBJECTIVES: The authors report the first clinical experience with the Conformal Left Atrial Appendage Seal (CLAAS) device. BACKGROUND: The CLAAS device was designed to address the limitations of first-generation left atrial appendage closure (LAAC) devices by providing an implant that is minimally traumatic, can be deployed in a noncoaxial fashion, and does not require postprocedural oral anticoagulation. METHODS: Patients with atrial fibrillation at high stroke risk (CHA2DS2-VASc score ≥2) were recruited using standard selection criteria. The LAAC procedure was guided by transesophageal echocardiography with patients under general anesthesia. The CLAAS device is composed of a foam cup, with a Nitinol endoskeleton with an expanded polytetrafluoroethylene cover, delivered with a standard delivery system using a tether for full recapture. All patients received dual-antiplatelet therapy for 6 months, followed by aspirin alone. Transesophageal echocardiographic follow-up was scheduled for 45 days and 1 year. RESULTS: Twenty-two patients (63.7% with CHA2DS2-VASc scores ≥3, 76.2% with HAS-BLED scores ≥3) were enrolled. The device was successfully implanted in 18 patients and unsuccessfully in 4 patients. There were no serious procedural complications. On transesophageal echocardiography performed at 45 days, 1 significant leak (≥5 mm) was seen, which was due to a large posterior lobe not appreciated at the time of implantation, and 1 device-related thrombus was noted, which resolved on oral anticoagulation. There were no periprocedural strokes, major pericardial effusions, or systemic or device embolization. CONCLUSIONS: This first-in-human study demonstrates the clinical feasibility of the CLAAS device for LAAC.

Preclinical Assessment of a Novel Conformable Foam-Based Left Atrial Appendage Closure Device.

BACKGROUND: Left atrial appendage (LAA) occlusion has been established as an alternative to systemic anticoagulation for stroke prevention in patients with atrial fibrillation; however, limitations of current devices have slowed adoption. We present preclinical evaluations of a novel device, the Conformal Left Atrial Appendage Seal (CLAAS). METHODS: An in vitro assessment of conformability was conducted to evaluate the two CLAAS devices (regular 27 mm and large 35 mm) and a Watchman 2.5 (27 mm). Devices were placed within silicone tubes and compressed in a vise submerged in a water bath at 37°C. Changes in device diameter and visual seal were noted. Acute (n = 1) and chronic 60-day (n = 6) canine studies with gross and histologic assessment were performed. RESULTS: Conformability bench tests demonstrated that the regular CLAAS implant was able to seal oval orifices from 20 × 30 mm to 15 × 33 mm and the large from 30 × 35 mm to 20 × 40 mm. As the CLAAS implant was compressed in the minor diameter, it increased in the major diameter, thereby filling the oval space, whereas the Watchman 2.5 showed gaps and maintained its round configuration when compressed in one direction. Seven devices were successfully implanted in the canine model with complete seal without thrombus. Histologic examination showed complete neointima covering with minimal inflammation at 60 days. CONCLUSIONS: Preclinical testing demonstrated the conformability of the CLAAS implant and its ability to seal the LAA. Clinical studies are ongoing to characterize the utility of the CLAAS implant in the treatment of patients with atrial fibrillation.

Funding of Studies Supporting IA Guideline Recommendations in Cardiovascular Medicine-A Systematic Review.

Each guideline recommendation from the American Heart Association and the American College of Cardiology includes an indication of the level of supporting evidence and the associated strength of recommendation with "IA" recommendations representing those with the highest quality supporting evidence and the least amount of uncertainty for benefit. In this analysis, study type and funding sources were systematically tabulated across these IA guideline recommendations over the past 5 years. Nearly half of studies supporting IA guideline recommendations were randomized controlled trials (45%). Overall, about one third of studies supporting IA recommendations were publicly funded (34.9%) with slightly more funded through industry sources (43.5%). Funding sources varied based on the type of intervention being studied with randomized controlled trials of device, diagnostic, and pharmacological interventions reflecting predominantly industry-funded studies. Over time, studies supporting IA cardiology guideline are funded by industry about twice as often as public sources. Thus, data of adequate quality to support cardiovascular guideline recommendations come from a variety of sources.

Early Feasibility Studies for Cardiovascular Devices in the United States: JACC State-of-the-Art Review.

The development of technology to treat unmet clinical patient needs in the United States has been an important focus for the U.S. Food and Drug Administration and the 2016 Congressional 21st Century Cures Act. In response, a program of early feasibility studies (EFS) has been developed. One of the important issues has been the outmigration of the development and testing of medical devices from the United States. The EFS committee has developed and implemented processes to address issues to develop strategies for early treatment of these patient groups. Initial implementation of the U.S. Food and Drug Administration EFS program has been successful, but residual significant problems have hindered the opportunity to take full advantage of the program. These include delays in gaining Institutional Review Board approval, timeliness of budget and contractual negotiations, and lack of access to and enrollment of study subjects. This paper reviews improvements that have been made to the U.S. EFS ecosystem and outlines potential approaches to address remaining impediments to program success.

Redefining the Prognostic Value of High-Sensitivity Troponin in COVID-19 Patients: The Importance of Concomitant Coronary Artery Disease.

BACKGROUND: Although studies assessing cardiovascular comorbidities and myocardial injury in Coronavirus disease 2019 (COVID-19) patients have been published, no reports focused on clinical outcomes of myocardial injury in patients with and without chronic coronary syndromes (CCS) are currently available. METHODS: In this study, consecutive COVID-19 patients admitted to four different institutions were screened for enrolment. Patients were divided into two groups (CCS vs. no-CCS). Association with in-hospital mortality and related predictors represented the main study outcome; myocardial injury and its predictors were deemed secondary outcomes. RESULTS: A total of 674 COVID-19 patients were enrolled, 112 (16.6%) with an established history of CCS. Myocardial injury occurred in 43.8% patients with CCS vs. 14.4% patients without CCS, as confirmed by high-sensitivity cardiac troponin (hs-cTn) elevation on admission or during hospitalization. The mortality rate in the CCS cohort was nearly three-fold higher. After adjusting for disease severity, myocardial injury resulted significantly associated with in-hospital mortality in the no-CCS group but not in CCS patients. CONCLUSIONS: Patients with CCS and COVID-19 showed high mortality rate. Myocardial injury may be a bystander in CCS patients and COVID-19, while in patients without known history of CCS, myocardial injury has a significant role in predicting poor outcomes.

Dofetilide-Associated QT Prolongation: Total Body Weight Versus Adjusted or Ideal Body Weight for Dosing.

Dofetilide is an antiarrhythmic drug with dosing based on the Cockcroft-Gault formula using total body weight (TBW). We investigated the impact of calculating dofetilide dose using adjusted body weight (ABW) or ideal body weight (IBW) on subsequent dose reduction or discontinuation. We conducted a retrospective review of 265 patients admitted to an academic medical center for initiation of dofetilide using TBW. Dosing was recalculated using ABW or IBW. Patients who would have received a reduced dose using ABW or IBW (reduced dose group) were compared with patients whose dose would not have changed (same dose group). Manual measurement of QT intervals was performed. We found that Forty-one of 265 patients (15%) would have received a lower initial dose of dofetilide based on ABW. Patients in this reduced dose group had 2.95 times greater odds of drug discontinuations or dose reductions due to QTc prolongation (95% confidence interval, 1.47-5.90; P < 0.01) compared with the same dose group. Seventy-seven of 265 patients (29%) would have received a lower initial dose of dofetilide based on IBW. Patients in this reduced dose group had 1.78 times greater odds of drug discontinuations or dose reductions due to QTc prolongation (95% confidence interval, 0.98-3.21; P = 0.056) compared with the same dose group. These data suggest that caution should be used when dosing dofetilide using TBW, as it may lead to a greater frequency of dose reduction or discontinuation compared with dosing using ABW or IBW.

Spontaneous Closure of a Secundum Atrial Septal Defect.

Spontaneous closure of an atrial septal defect (ASD) is well described in pediatric cardiology but may be less familiar to adult internists and cardiologists. We report a moderately sized 6-mm ASD that closed spontaneously without intervention. A literature review found that a smaller defect size and an early age of diagnosis are the most important predictors of closure. Possible mechanisms of a spontaneous ASD closure include adaptive endothelial migration, limited myocardial proliferation, and fibroblast migration with extracellular matrix deposition.

Visual estimation versus different quantitative coronary angiography methods to assess lesion severity in bifurcation lesions.

OBJECTIVES: To compare visual estimation with different quantitative coronary angiography (QCA) methods (single-vessel versus bifurcation software) to assess coronary bifurcation lesions. BACKGROUND: QCA has been developed to overcome the limitations of visual estimation. Conventional QCA however, developed in "straight vessels," has proved to be inaccurate in bifurcation lesions. Therefore, bifurcation QCA was developed. However, the impact of these different modalities on bifurcation lesion severity classification is yet unknown METHODS: From a randomized controlled trial investigating a novel bifurcation stent (Clinicaltrials.gov NCT01258972), patients with baseline assessment of lesion severity by means of visual estimation, single-vessel QCA, 2D bifurcation QCA and 3D bifurcation QCA were included. We included 113 bifurcations lesions in which all 5 modalities were assessed. The primary end-point was to evaluate how the different modalities affected the classification of bifurcation lesion severity and extent of disease. RESULTS: On visual estimation, 100% of lesions had side-branch diameter stenosis (%DS) >50%, whereas in 83% with single-vessel QCA, 27% with 2D bifurcation QCA and 26% with 3D bifurcation QCA a side-branch %DS >50% was found (P < 0.0001). With regard to the percentage of "true" bifurcation lesions, there was a significant difference between visual estimate (100%), single-vessel QCA (75%) and bifurcation QCA (17% with 2D bifurcation software and 13% with 3D bifurcation software, P < 0.0001). CONCLUSIONS: Our study showed that bifurcation lesion complexity was significantly affected when more advanced bifurcation QCA software were used. "True" bifurcation lesion rate was 100% on visual estimation, but as low as 13% when analyzed with dedicated bifurcation QCA software.

Atrial Fibrillation and Stent Selection (Bare Metal vs Drug Eluting) (from Medicare Claims).

In treating coronary artery disease, many factors influence the choice of bare metal stent (BMS) or drug-eluting stent (DES), including bleed risk and suitability for prolonged dual antiplatelet therapy. Atrial fibrillation (AF) further complicates this choice, due to common use of anticoagulation. We examined stent selection in the United States by AF status and across academic medical centers (AMCs) to explore how cardiologists are managing this complex choice. Using a 100% Medicare denominator file and associated claims (2008 to 2012), we identified patients over age 65 receiving inpatient coronary artery stents. We measured BMS and DES use in patients with AF and in patients without AF and assessed variation in stent choice across AMCs, adjusting for differences in age, gender, and race. We identified 898,788 stent episodes among elderly Medicare beneficiaries. BMS, as a percentage of total inpatient stent episodes, decreased from 2008 to 2012, in patients with AF (42% to 34%) and in patients without AF (32% to 23%). Across AMCs, adjusted stent choice varied substantially, but more so for patients with AF (2008 to 2012 median BMS 44% to 39%, annual interquartile ratios range 1.8 to 2.3) than patients without AF (2008 to 2012 median BMS 33% to 25%, annual interquartile ratios range 2.0 to 1.8). In conclusion, among stent recipients, patients with AF are more likely to receive BMS than patients without AF but treatment varies across systems, suggesting a lack of consensus. Studies of stent choice and outcomes among patients with AF are needed to guide care decisions and optimize outcomes.

HS3ST1 genotype regulates antithrombin's inflammomodulatory tone and associates with atherosclerosis.

The HS3ST1 gene controls endothelial cell production of HSAT+ - a form of heparan sulfate containing a specific pentasaccharide motif that binds the anticoagulant protein antithrombin (AT). HSAT+ has long been thought to act as an endogenous anticoagulant; however, coagulation was normal in Hs3st1-/- mice that have greatly reduced HSAT+ (HajMohammadi et al., 2003). This finding indicates that HSAT+ is not essential for AT's anticoagulant activity. To determine if HSAT+ is involved in AT's poorly understood inflammomodulatory activities, Hs3st1-/- and Hs3st1+/+ mice were subjected to a model of acute septic shock. Compared with Hs3st1+/+ mice, Hs3st1-/- mice were more susceptible to LPS-induced death due to an increased sensitivity to TNF. For Hs3st1+/+ mice, AT treatment reduced LPS-lethality, reduced leukocyte firm adhesion to endothelial cells, and dilated isolated coronary arterioles. Conversely, for Hs3st1-/- mice, AT induced the opposite effects. Thus, in the context of acute inflammation, HSAT+ selectively mediates AT's anti-inflammatory activity; in the absence of HSAT+, AT's pro-inflammatory effects predominate. To explore if the anti-inflammatory action of HSAT+ also protects against a chronic vascular-inflammatory disease, atherosclerosis, we conducted a human candidate-gene association study on >2000 coronary catheterization patients. Bioinformatic analysis of the HS3ST1 gene identified an intronic SNP, rs16881446, in a putative transcriptional regulatory region. The rs16881446G/G genotype independently associated with the severity of coronary artery disease and atherosclerotic cardiovascular events. In primary endothelial cells, the rs16881446G allele associated with reduced HS3ST1 expression. Together with the mouse data, this leads us to conclude that the HS3ST1 gene is required for AT's anti-inflammatory activity that appears to protect against acute and chronic inflammatory disorders.

Segmental comparison between a dedicated bifurcation stent and balloon angioplasty using intravascular ultrasound and three-dimensional quantitative coronary angiography: A subgroup analysis of the Tryton IDE randomized trial.

OBJECTIVE: Randomized comparison between the Tryton Side Branch Stent (Tryton Medical, Durham, NC), used in combination with a main branch drug-eluting stent (DES), and side branch balloon angioplasty (SBBA, in combination with a main branch DES) using intravascular ultrasound (IVUS), and three-dimensional quantitative coronary angiography (3D-QCA). BACKGROUND: The Tryton stent has been developed to improve clinical outcomes after percutaneous coronary intervention (PCI) of bifurcation lesions. METHODS: We present the pre-specified IVUS (n = 159) and 3D-QCA (n = 190) sub-group analyses of the Tryton coronary bifurcation trial (randomizing Tryton vs. SBBA). RESULTS: There were no differences in the main branch with regard to minimal lumen area (MLA) (5.33 ± 1.37 in Tryton vs. 5.69 ± 1.72 mm2 in SBBA, P = 0.235) with low neo-intima area in both groups. In the side branch, there were also no statistical significant differences between both groups (3.04 ± 1.02 in Tryton vs. 3.46 ± 1.15 mm2 in SBBA, P = 0.072). On 3D-QCA, no differences in minimal lumen diameter (MLD) and percentage diameter stenosis (%DS) were observed in the proximal and distal main branches. In the side branch, there were also no differences found in %DS and MLD (MLD: 1.34 ± 0.043 mm [Tryton] vs. 1.45 ± 0.31 mm [SBBA], P = 0.090). CONCLUSIONS: There were no differences in 9-month luminal dimensions of the side branch between the Tryton Stent and Side Branch Balloon Angioplasty, as assessed with IVUS (MLA) and 3D QCA (MLD). Angiographic and ultrasound results of the main branch were not negatively influenced by the Tryton stent. © 2016 Wiley Periodicals, Inc.

Dedicated Bifurcation Stent for the Treatment of Bifurcation Lesions Involving Large Side Branches: Outcomes From the Tryton Confirmatory Study.

OBJECTIVES: The aim of this study was to prospectively study and confirm the safety and efficacy of the Tryton Side Branch Stent in the treatment of coronary artery bifurcations involving large side branches (SBs). BACKGROUND: The TRYTON Pivotal randomized controlled trial (RCT) was designed to compare the Tryton stent with standard provisional SB stenting in large vessels. The trial inadvertently enrolled patients with too small SBs (<2.25 mm). The overall trial did not meet its primary endpoint, because of an increased rate of periprocedural myocardial infarction in the Tryton stent arm. A post hoc analysis restricted to the intended population showed that the trial would have met its endpoint if only patients with SBs ≥2.25 mm in diameter (by core laboratory quantitative coronary angiography) had been enrolled. METHODS: The Tryton Confirmatory Study was a prospective, single-arm extension of the TRYTON Pivotal RCT that enrolled an additional 133 patients treated with the Tryton Side Branch Stent. It was designed to confirm the results of the post hoc analysis and emphasized the inclusion of appropriately sized SBs. The primary endpoint was noninferiority with regard to periprocedural myocardial infarction (creatine kinase myocardial band 3 times the upper limit of normal) compared with a performance goal based on the TRYTON Pivotal RCT. RESULTS: Among the 133 enrolled patients, 132 (99.2%) had SBs ≥2.25 mm. Baseline clinical and angiographic parameters were similar in this study and the RCT. Periprocedural myocardial infarction occurred in 10.5% of patients, which was numerically lower than the provisional group in the TRYTON Pivotal RCT (11.9%). The 95% confidence bounds did not extend beyond the pre-defined performance goal of 17.9%, meeting the noninferiority primary endpoint. CONCLUSIONS: The Tryton Confirmatory Study, in conjunction with the post hoc analysis of the intended population in the TRYTON Pivotal RCT, supports the safety and efficacy of the Tryton Side Branch Stent for treatment of bifurcation lesions involving large SBs.

Outcomes of a dedicated stent in coronary bifurcations with large side branches: A subanalysis of the randomized TRYTON bifurcation study.

OBJECTIVES: To examine the benefit of the Tryton dedicated side branch (SB) stent compared with provisional stenting in the treatment of complex bifurcation lesions involving large SBs. BACKGROUND: The TRYTON Trial was designed to evaluate the utility of a dedicated SB stent to treat true bifurcation lesions involving large (≥2.5 mm by visual estimation) SBs. Patient enrolled in the trial had smaller SB diameters than intended (59% SB ≤2.25 mm by Core Lab QCA). The TRYTON Trial did not meet its primary endpoint due to an increased rate of peri-procedural myocardial infarctions (MIs). METHODS: The TRYTON Trial randomized 704 patients to the Tryton SB stent with main vessel DES versus provisional SB treatment with main vessel DES. The rates of the primary end point of target vessel failure and the secondary powered end point of angiographic percent diameter stenosis in the SB at 9 months were assessed and compared between the two treatment strategies among patients with a SB ≥2.25 mm diameter at baseline determined by Core Lab QCA. RESULTS: Among the 704 patients enrolled in the TRYTON Trial, 289 patients (143 provisional and 146 Tryton stent; 41% of entire cohort) had a SB ≥2.25 mm. The primary end point of TVF was numerically lower in the Tryton group compared with the provisional group (11.3% vs. 15.6%, P = 0.38), and was within the non-inferiority margin. No difference among the rates of clinically driven target vessel revascularization (3.5% vs. 4.3% P = 0.77) or cardiac death (0% both groups) were seen. In-segment percent diameter stenosis of the SB was significantly lower in the Tryton group compared with the provisional group (30.4% vs. 40.6%, P = 0.004). CONCLUSIONS: Analysis of the TRYTON Trial cohort of SB ≥2.25 mm supports the safety and efficacy of the Tryton SB stent compared with a provisional stenting strategy in the treatment of bifurcation lesions involving large SBs. © 2015 Wiley Periodicals, Inc.

A randomized trial of a dedicated bifurcation stent versus provisional stenting in the treatment of coronary bifurcation lesions.

BACKGROUND: Bifurcation lesions are frequent among patients with symptomatic coronary disease treated by percutaneous coronary intervention. Current evidence recommends a conservative (provisional) approach when treating the side branch (SB). OBJECTIVES: The TRYTON (Prospective, Single Blind, Randomized Controlled Study to Evaluate the Safety & Effectiveness of the Tryton Side Branch Stent Used With DES in Treatment of de Novo Bifurcation Lesions in the Main Branch & Side Branch in Native Coronaries) bifurcation trial sought to compare treatment of de novo true bifurcation lesions using a dedicated bifurcation stent or SB balloon angioplasty. METHODS: We randomly assigned patients with true bifurcation lesions to a main vessel stent plus provisional stenting or the bifurcation stent. The primary endpoint (powered for noninferiority) was target vessel failure (TVF) (cardiac death, target vessel myocardial infarction, and target vessel revascularization). The secondary angiographic endpoint (powered for superiority) was in-segment percent diameter stenosis of the SB at 9 months. RESULTS: We randomized 704 patients with bifurcation coronary lesions at 58 centers (30 from Europe and 28 from the United States). At 9 months, TVF was 17.4% in the bifurcation stent group compared with 12.8% in the provisional group (p=0.11), mainly because of a higher periprocedural myocardial infarction rate (13.6% vs. 10.1%, p=0.19). The TVF difference of +4.6% (2-sided 95% confidence interval: -1.0 to 10.3; upper limit of the 1-sided 95% confidence interval: 10.3) was not within the pre-specified noninferiority margin of 5.5% (p=0.42 for noninferiority). The SB in-segment diameter stenosis among the angiographic cohort was lower in the bifurcation stent group compared with the provisional group (31.6% vs. 38.6%, p=0.002 for superiority), with no difference in binary restenosis rates (diameter stenosis≥50%) at 9 months follow-up (22.6% vs. 26.8%, p=0.44). CONCLUSIONS: Provisional stenting should remain the preferred strategy for treatment of non-left main true coronary bifurcation lesions. (Prospective, Single Blind, Randomized Controlled Study to Evaluate the Safety & Effectiveness of the Tryton Side Branch Stent Used With DES in Treatment of de Novo Bifurcation Lesions in the Main Branch & Side Branch in Native Coronaries [TRYTON]; NCT01258972).